Refactored Dropbox, WebDAV & OneDrive to HTTPFileProvider

- FileOperationType.source is not optional anymore - critical bugfix: KVO exception crash on task completion
Merge pull request #60 from evilutioner/master
2017-08-19 05:51:25 +04:30 · 2017-08-15 18:53:21 +04:30 · 2017-08-15 18:41:48 +04:30 · 2017-08-15 16:57:50 +03:00 · 2017-08-15 15:08:06 +04:30 · 2017-08-15 14:57:36 +04:30
54 changed files with 9195 additions and 2618 deletions
@@ -1,27 +1,81 @@
 language: objective-c
-osx_image: xcode8
-xcode_project: FileProvider.xcodeproj
+osx_image: xcode8.2
+xcode_project: $PROJECTNAME.xcodeproj
 env:
  global: 
-    - FRAMEWORK_NAME=FileProvider.framework
+  - PROJECT="$PROJECTNAME.xcodeproj"
+  - FRAMEWORK_NAME="$PROJECTNAME.framework"
+  - IOS_FRAMEWORK_SCHEME="$PROJECTNAME iOS"
+  - MACOS_FRAMEWORK_SCHEME="$PROJECTNAME OSX"
+  - TVOS_FRAMEWORK_SCHEME="$PROJECTNAME tvOS"
+  - IOS_SDK=iphonesimulator
+  - MACOS_SDK=macosx
+  - TVOS_SDK=appletvsimulator
+  matrix:
+    - DESTINATION="OS=10.2,name=iPad Air 2"        SCHEME="$IOS_FRAMEWORK_SCHEME"     SDK="$IOS_SDK"     RUN_TESTS="NO" BUILD_EXAMPLE="NO" POD="NO" CARTHAGEDEPLOY="YES"
+    - DESTINATION="OS=9.0,name=iPhone 6"           SCHEME="$IOS_FRAMEWORK_SCHEME"     SDK="$IOS_SDK"     RUN_TESTS="NO" BUILD_EXAMPLE="NO" POD="YES"  CARTHAGEDEPLOY="NO"
+    - DESTINATION="OS=8.1,name=iPhone 4S"          SCHEME="$IOS_FRAMEWORK_SCHEME"     SDK="$IOS_SDK"     RUN_TESTS="NO" BUILD_EXAMPLE="NO" POD="NO"  CARTHAGEDEPLOY="NO"
+
+    - DESTINATION="OS=10.1,name=Apple TV 1080p"    SCHEME="$TVOS_FRAMEWORK_SCHEME"    SDK="$TVOS_SDK"    RUN_TESTS="NO" BUILD_EXAMPLE="NO" POD="NO"  CARTHAGEDEPLOY="NO"
+    # - DESTINATION="OS=10.0,name=Apple TV 1080p"    SCHEME="$TVOS_FRAMEWORK_SCHEME"    SDK="$TVOS_SDK"    RUN_TESTS="NO" BUILD_EXAMPLE="NO" POD="NO"  CARTHAGEDEPLOY="NO"
+
+    - DESTINATION="arch=x86_64"                    SCHEME="$MACOS_FRAMEWORK_SCHEME"   SDK="$MACOS_SDK"   RUN_TESTS="NO" BUILD_EXAMPLE="NO" POD="NO"  CARTHAGEDEPLOY="NO"
 before_install:
  - gem install xcpretty --no-rdoc --no-ri --no-document --quiet
-  - brew update
-  - brew outdated carthage || brew upgrade carthage
+  - gem install cocoapods --no-rdoc --no-ri --no-document --quiet
+  # - gem install xcpretty-travis-formatter
+
 script:
-  - set pipefail
+  - set -o pipefail
  - xcodebuild -version
-  - xcodebuild -project FileProvider.xcodeproj -scheme "FileProvider OSX" -sdk macosx | xcpretty
-  - xcodebuild -project FileProvider.xcodeproj -scheme "FileProvider iOS" -sdk iphonesimulator ONLY_ACTIVE_ARCH=NO | xcpretty
-  - xcodebuild -project FileProvider.xcodeproj -scheme "FileProvider tvOS" -sdk appletvsimulator ONLY_ACTIVE_ARCH=NO | xcpretty
-  - pod lib lint --quick
+
+  # Build Example in Debug if specified
+  - if [ $BUILD_EXAMPLE == "YES" ]; then
+      xcodebuild -project "$WORKSPACE" -scheme "$EXAMPLE_SCHEME" -sdk "$SDK" -destination "$DESTINATION" -configuration Debug ONLY_ACTIVE_ARCH=NO build | xcpretty;
+    fi
+
+  # Build Framework in Debug and Run Tests if specified
+  - if [ $RUN_TESTS == "YES" ]; then
+      xcodebuild -project "$PROJECT" -scheme "$SCHEME" -sdk "$SDK" -destination "$DESTINATION" -configuration Debug ONLY_ACTIVE_ARCH=NO ENABLE_TESTABILITY=YES test | xcpretty;
+    else
+      xcodebuild -project "$PROJECT" -scheme "$SCHEME" -sdk "$SDK" -destination "$DESTINATION" -configuration Debug ONLY_ACTIVE_ARCH=NO build | xcpretty;
+    fi
+
+  # Build Framework in Release and Run Tests if specified
+  - if [ $RUN_TESTS == "YES" ]; then
+      xcodebuild -project "$PROJECT" -scheme "$SCHEME" -sdk "$SDK" -destination "$DESTINATION" -configuration Release ONLY_ACTIVE_ARCH=NO ENABLE_TESTABILITY=YES test | xcpretty;
+    else
+      xcodebuild -project "$PROJECT" -scheme "$SCHEME" -sdk "$SDK" -destination "$DESTINATION" -configuration Release ONLY_ACTIVE_ARCH=NO build | xcpretty;
+    fi
+
+  # Run `pod lib lint` if specified
+  - if [ $POD == "YES" ]; then
+      pod lib lint --quick;
+    fi
+
 after_success:
-  - bash <(curl -s https://codecov.io/bash)
+  # Run `pod trunk push` if specified
+  - if [ $POD == "YES" ] && [ -n "$TRAVIS_TAG" ]; then
+      pod trunk push --allow-warnings;
+    fi
+
+#   - bash <(curl -s https://codecov.io/bash)
 before_deploy:
-  - carthage build --no-skip-current
-  - carthage archive FileProvider
+  - if [ $CARTHAGEDEPLOY == "YES" ] && [ -n "$TRAVIS_TAG" ]; then
+      brew update;
+      brew outdated carthage || brew upgrade carthage;
+      carthage version;
+      carthage build --no-skip-current --verbose;
+      carthage archive $PROJECTNAME;
+    fi
+
 deploy:
-  file: FileProvider.framework.zip
+  provider: releases
+  api_key: "$GITHUBTOKEN"
+  file: $FRAMEWORK_NAME.zip
  skip_cleanup: true
  on:
-    tags: true
+    # repo: amosavian/$PROJECTNAME
+    repo: amosavian/FileProvider
+    tags: true
+    condition: "$CARTHAGEDEPLOY = YES"
@@ -1,5 +1,5 @@
 #
-#  Be sure to run `pod spec lint FileProvider.podspec' to ensure this is a
+#  Be sure to run `pod spec lint FilesProvider.podspec' to ensure this is a
 #  valid spec and to remove all comments including this before submitting the spec.
 #
 #  To learn more about Podspec attributes see http://docs.cocoapods.org/specification.html
@@ -15,9 +15,9 @@ Pod::Spec.new do |s|
  #  summary should be tweet-length, and the description more in depth.
  #

-  s.name         = "FileProvider"
-  s.version      = "0.6.0"
-  s.summary      = "FileManager replacement for Local and Remote (WebDAV/Dropbox/SMB2) files on iOS and MacOS."
+  s.name         = "FilesProvider"
+  s.version      = "0.20.0"
+  s.summary      = "FileManager replacement for Local and Remote (WebDAV/FTP/Dropbox/OneDrive/SMB2) files on iOS and macOS."

  # This description is used to generate tags and improve search results.
  #   * Think: What does it do? Why did you write it? What is the focus?
@@ -26,8 +26,8 @@ Pod::Spec.new do |s|
  #   * Finally, don't worry about the indent, CocoaPods strips it!
  s.description  = <<-DESC
  					This Swift library provide a swifty way to deal with local and remote files 
-  					and directories in same way. For now Local and WebDAV providers are ready to use
-  					and SMB2, Dropbox, FTP and AmazonS3 is planned for future.
+  					and directories in same way. For now Local, WebDAV and Dropbox providers are ready to use.
+  				    SMB2, FTP and AmazonS3 is planned for future.
                   DESC

  s.homepage     = "https://github.com/amosavian/FileProvider"
@@ -10,9 +10,7 @@
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 		7902C0871D61B67100564440 /* RemoteSession.swift in Sources */ = {isa = PBXBuildFile; fileRef = 7902C0851D61B56D00564440 /* RemoteSession.swift */; };
 		7902C0881D61B67100564440 /* RemoteSession.swift in Sources */ = {isa = PBXBuildFile; fileRef = 7902C0851D61B56D00564440 /* RemoteSession.swift */; };
-		7924B1931D89DAE000589DB7 /* AEXML.h in Headers */ = {isa = PBXBuildFile; fileRef = 7924B18C1D89DAE000589DB7 /* AEXML.h */; };
-		7924B1941D89DAE000589DB7 /* AEXML.h in Headers */ = {isa = PBXBuildFile; fileRef = 7924B18C1D89DAE000589DB7 /* AEXML.h */; };
-		7924B1951D89DAE000589DB7 /* AEXML.h in Headers */ = {isa = PBXBuildFile; fileRef = 7924B18C1D89DAE000589DB7 /* AEXML.h */; };
+		791950F51DE58A5400B4426E /* libxml2.tbd in Frameworks */ = {isa = PBXBuildFile; fileRef = 791950F41DE58A5400B4426E /* libxml2.tbd */; };
 		7924B1961D89DAE000589DB7 /* Document.swift in Sources */ = {isa = PBXBuildFile; fileRef = 7924B18D1D89DAE000589DB7 /* Document.swift */; };
 		7924B1971D89DAE000589DB7 /* Document.swift in Sources */ = {isa = PBXBuildFile; fileRef = 7924B18D1D89DAE000589DB7 /* Document.swift */; };
 		7924B1981D89DAE000589DB7 /* Document.swift in Sources */ = {isa = PBXBuildFile; fileRef = 7924B18D1D89DAE000589DB7 /* Document.swift */; };
@@ -22,9 +20,6 @@
 		7924B19C1D89DAE000589DB7 /* Error.swift in Sources */ = {isa = PBXBuildFile; fileRef = 7924B18F1D89DAE000589DB7 /* Error.swift */; };
 		7924B19D1D89DAE000589DB7 /* Error.swift in Sources */ = {isa = PBXBuildFile; fileRef = 7924B18F1D89DAE000589DB7 /* Error.swift */; };
 		7924B19E1D89DAE000589DB7 /* Error.swift in Sources */ = {isa = PBXBuildFile; fileRef = 7924B18F1D89DAE000589DB7 /* Error.swift */; };
-		7924B19F1D89DAE000589DB7 /* Info.plist in Resources */ = {isa = PBXBuildFile; fileRef = 7924B1901D89DAE000589DB7 /* Info.plist */; };
-		7924B1A01D89DAE000589DB7 /* Info.plist in Resources */ = {isa = PBXBuildFile; fileRef = 7924B1901D89DAE000589DB7 /* Info.plist */; };
-		7924B1A11D89DAE000589DB7 /* Info.plist in Resources */ = {isa = PBXBuildFile; fileRef = 7924B1901D89DAE000589DB7 /* Info.plist */; };
 		7924B1A21D89DAE000589DB7 /* Options.swift in Sources */ = {isa = PBXBuildFile; fileRef = 7924B1911D89DAE000589DB7 /* Options.swift */; };
 		7924B1A31D89DAE000589DB7 /* Options.swift in Sources */ = {isa = PBXBuildFile; fileRef = 7924B1911D89DAE000589DB7 /* Options.swift */; };
 		7924B1A41D89DAE000589DB7 /* Options.swift in Sources */ = {isa = PBXBuildFile; fileRef = 7924B1911D89DAE000589DB7 /* Options.swift */; };
@@ -37,6 +32,15 @@
 		7924B1B11D89F7DF00589DB7 /* FPSStreamTask.swift in Sources */ = {isa = PBXBuildFile; fileRef = 7924B1A81D89F79200589DB7 /* FPSStreamTask.swift */; };
 		7924B1B21D89FCDA00589DB7 /* FPSStreamTask.swift in Sources */ = {isa = PBXBuildFile; fileRef = 7924B1A81D89F79200589DB7 /* FPSStreamTask.swift */; };
 		7924B1B31D89FD6400589DB7 /* SMBClient.swift in Sources */ = {isa = PBXBuildFile; fileRef = 799396971D48C02300086753 /* SMBClient.swift */; };
+		792572411DF23BDA006A1526 /* LocalHelper.swift in Sources */ = {isa = PBXBuildFile; fileRef = 792572401DF23BDA006A1526 /* LocalHelper.swift */; };
+		792572421DF23BDA006A1526 /* LocalHelper.swift in Sources */ = {isa = PBXBuildFile; fileRef = 792572401DF23BDA006A1526 /* LocalHelper.swift */; };
+		792572431DF23BDA006A1526 /* LocalHelper.swift in Sources */ = {isa = PBXBuildFile; fileRef = 792572401DF23BDA006A1526 /* LocalHelper.swift */; };
+		7936BC121E880F5700A6C81C /* FTPFileProvider.swift in Sources */ = {isa = PBXBuildFile; fileRef = 7936BC111E880F5700A6C81C /* FTPFileProvider.swift */; };
+		7936BC131E880F5700A6C81C /* FTPFileProvider.swift in Sources */ = {isa = PBXBuildFile; fileRef = 7936BC111E880F5700A6C81C /* FTPFileProvider.swift */; };
+		7936BC141E880F5700A6C81C /* FTPFileProvider.swift in Sources */ = {isa = PBXBuildFile; fileRef = 7936BC111E880F5700A6C81C /* FTPFileProvider.swift */; };
+		79480FF61E3ABDD0007E7275 /* CloudFileProvider.swift in Sources */ = {isa = PBXBuildFile; fileRef = 79480FF51E3ABDD0007E7275 /* CloudFileProvider.swift */; };
+		79480FF71E3ABDD0007E7275 /* CloudFileProvider.swift in Sources */ = {isa = PBXBuildFile; fileRef = 79480FF51E3ABDD0007E7275 /* CloudFileProvider.swift */; };
+		79480FF81E3ABDD0007E7275 /* CloudFileProvider.swift in Sources */ = {isa = PBXBuildFile; fileRef = 79480FF51E3ABDD0007E7275 /* CloudFileProvider.swift */; };
 		794C21FE1D58912A00EC49B8 /* DropboxHelper.swift in Sources */ = {isa = PBXBuildFile; fileRef = 794C21FD1D58912A00EC49B8 /* DropboxHelper.swift */; };
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@@ -46,6 +50,13 @@
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 		794C220F1D591A4B00EC49B8 /* SMB2QueryTypes.swift in Sources */ = {isa = PBXBuildFile; fileRef = 794C220D1D591A4B00EC49B8 /* SMB2QueryTypes.swift */; };
 		794C22101D591A4B00EC49B8 /* SMB2QueryTypes.swift in Sources */ = {isa = PBXBuildFile; fileRef = 794C220D1D591A4B00EC49B8 /* SMB2QueryTypes.swift */; };
+		7958155A1F478ED9003344DD /* HTTPFileProvider.swift in Sources */ = {isa = PBXBuildFile; fileRef = 795815591F478ED9003344DD /* HTTPFileProvider.swift */; };
+		7958155B1F478ED9003344DD /* HTTPFileProvider.swift in Sources */ = {isa = PBXBuildFile; fileRef = 795815591F478ED9003344DD /* HTTPFileProvider.swift */; };
+		7958155C1F478ED9003344DD /* HTTPFileProvider.swift in Sources */ = {isa = PBXBuildFile; fileRef = 795815591F478ED9003344DD /* HTTPFileProvider.swift */; };
+		796807551E7BF17E00BBB87B /* FileProviderExtensions.swift in Sources */ = {isa = PBXBuildFile; fileRef = 796807541E7BF17E00BBB87B /* FileProviderExtensions.swift */; };
+		796807561E7BF17E00BBB87B /* FileProviderExtensions.swift in Sources */ = {isa = PBXBuildFile; fileRef = 796807541E7BF17E00BBB87B /* FileProviderExtensions.swift */; };
+		796807571E7BF17E00BBB87B /* FileProviderExtensions.swift in Sources */ = {isa = PBXBuildFile; fileRef = 796807541E7BF17E00BBB87B /* FileProviderExtensions.swift */; };
+		798654331E8874BC002FA550 /* FTPHelper.swift in Sources */ = {isa = PBXBuildFile; fileRef = 798654321E8874BC002FA550 /* FTPHelper.swift */; };
 		799396AA1D48C02300086753 /* DropboxFileProvider.swift in Sources */ = {isa = PBXBuildFile; fileRef = 799396931D48C02300086753 /* DropboxFileProvider.swift */; };
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@@ -94,24 +105,54 @@
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 /* Begin PBXFrameworksBuildPhase section */
@@ -140,6 +196,10 @@
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+				79BD63AC1E2CC2C20035128C /* ImageIO.framework in Frameworks */,
+				79BD63A81E2CC2940035128C /* CoreGraphics.framework in Frameworks */,
+				791950F51DE58A5400B4426E /* libxml2.tbd in Frameworks */,
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@@ -147,6 +207,10 @@
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+				79BD63B81E2CC38D0035128C /* AVFoundation.framework in Frameworks */,
+				79BD63B61E2CC3860035128C /* CoreFoundation.framework in Frameworks */,
+				79BD63B21E2CC3350035128C /* ImageIO.framework in Frameworks */,
+				79BD63B01E2CC3300035128C /* libxml2.tbd in Frameworks */,
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@@ -154,20 +218,41 @@
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+				79BD63BE1E2CC3C20035128C /* ImageIO.framework in Frameworks */,
+				79BD63BA1E2CC39B0035128C /* libxml2.tbd in Frameworks */,
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 /* End PBXFrameworksBuildPhase section */

 /* Begin PBXGroup section */
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+				79BD63BF1E2CC3CD0035128C /* CoreGraphics.framework */,
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+				79BD63B51E2CC3860035128C /* CoreFoundation.framework */,
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+				79BD63A91E2CC2BB0035128C /* AVFoundation.framework */,
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@@ -177,18 +262,20 @@
 		7993965B1D48B7BF00086753 = {
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 			children = (
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 				799396911D48C02300086753 /* Sources */,
 				7993968A1D48B8C700086753 /* Pod */,
 				799396681D48B7F600086753 /* Products */,
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-				799396751D48B80D00086753 /* FileProvider.framework */,
-				799396821D48B82700086753 /* FileProvider.framework */,
+				799396671D48B7F600086753 /* FilesProvider.framework */,
+				799396751D48B80D00086753 /* FilesProvider.framework */,
+				799396821D48B82700086753 /* FilesProvider.framework */,
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@@ -206,18 +293,28 @@
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-				799396931D48C02300086753 /* DropboxFileProvider.swift */,
 				7924B18B1D89DAE000589DB7 /* AEXML */,
-				794C21FD1D58912A00EC49B8 /* DropboxHelper.swift */,
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 				799396941D48C02300086753 /* FileProvider.h */,
 				799396951D48C02300086753 /* FileProvider.swift */,
+				796807541E7BF17E00BBB87B /* FileProviderExtensions.swift */,
+				79F5745A1DFDB10A00179ABF /* FileObject.swift */,
 				799396961D48C02300086753 /* LocalFileProvider.swift */,
-				7902C0851D61B56D00564440 /* RemoteSession.swift */,
+				792572401DF23BDA006A1526 /* LocalHelper.swift */,
+				79480FF51E3ABDD0007E7275 /* CloudFileProvider.swift */,
+				79BD638B1E2CC2300035128C /* ExtendedLocalFileProvider.swift */,
 				7924B1A81D89F79200589DB7 /* FPSStreamTask.swift */,
+				7902C0851D61B56D00564440 /* RemoteSession.swift */,
+				795815591F478ED9003344DD /* HTTPFileProvider.swift */,
+				799396931D48C02300086753 /* DropboxFileProvider.swift */,
+				794C21FD1D58912A00EC49B8 /* DropboxHelper.swift */,
+				79BD63C31E2D17880035128C /* OneDriveFileProvider.swift */,
+				79BD63C41E2D17880035128C /* OneDriveHelper.swift */,
+				799396A61D48C02300086753 /* WebDAVFileProvider.swift */,
+				7936BC111E880F5700A6C81C /* FTPFileProvider.swift */,
+				798654321E8874BC002FA550 /* FTPHelper.swift */,
 				799396971D48C02300086753 /* SMBClient.swift */,
 				799396981D48C02300086753 /* SMBFileProvider.swift */,
-				799396A61D48C02300086753 /* WebDAVFileProvider.swift */,
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 			path = Sources;
 			sourceTree = "<group>";
@@ -242,6 +339,13 @@
 			path = SMBTypes;
 			sourceTree = "<group>";
 		};
+		79E34A101E2AC6C600E1293B /* Extra */ = {
+			isa = PBXGroup;
+			children = (
+			);
+			name = Extra;
+			sourceTree = "<group>";
+		};
 /* End PBXGroup section */

 /* Begin PBXHeadersBuildPhase section */
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 /* End PBXHeadersBuildPhase section */

 /* Begin PBXNativeTarget section */
-		799396661D48B7F600086753 /* FileProvider iOS */ = {
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-			buildConfigurationList = 7993966F1D48B7F600086753 /* Build configuration list for PBXNativeTarget "FileProvider iOS" */;
+			buildConfigurationList = 7993966F1D48B7F600086753 /* Build configuration list for PBXNativeTarget "FilesProvider iOS" */;
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@@ -285,14 +386,14 @@
 			);
 			dependencies = (
 			);
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+			name = "FilesProvider iOS";
 			productName = "FileProvider iOS";
-			productReference = 799396671D48B7F600086753 /* FileProvider.framework */;
+			productReference = 799396671D48B7F600086753 /* FilesProvider.framework */;
 			productType = "com.apple.product-type.framework";
 		};
-		799396741D48B80D00086753 /* FileProvider OSX */ = {
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 			isa = PBXNativeTarget;
-			buildConfigurationList = 7993967A1D48B80D00086753 /* Build configuration list for PBXNativeTarget "FileProvider OSX" */;
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@@ -303,14 +404,14 @@
 			);
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+			name = "FilesProvider OSX";
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-			productReference = 799396751D48B80D00086753 /* FileProvider.framework */;
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-		799396811D48B82700086753 /* FileProvider tvOS */ = {
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-			buildConfigurationList = 799396871D48B82700086753 /* Build configuration list for PBXNativeTarget "FileProvider tvOS" */;
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@@ -321,9 +422,9 @@
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+			name = "FilesProvider tvOS";
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-			productReference = 799396821D48B82700086753 /* FileProvider.framework */;
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 			attributes = {
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-			buildConfigurationList = 7993965F1D48B7BF00086753 /* Build configuration list for PBXProject "FileProvider" */;
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 			developmentRegion = English;
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-				799396741D48B80D00086753 /* FileProvider OSX */,
-				799396811D48B82700086753 /* FileProvider tvOS */,
+				799396661D48B7F600086753 /* FilesProvider iOS */,
+				799396741D48B80D00086753 /* FilesProvider OSX */,
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 				799396D41D48C02300086753 /* SMB2Tree.swift in Sources */,
 				7924B1A21D89DAE000589DB7 /* Options.swift in Sources */,
+				792572411DF23BDA006A1526 /* LocalHelper.swift in Sources */,
+				7936BC121E880F5700A6C81C /* FTPFileProvider.swift in Sources */,
+				79480FF61E3ABDD0007E7275 /* CloudFileProvider.swift in Sources */,
+				79F5745B1DFDB10B00179ABF /* FileObject.swift in Sources */,
+				79BD63C51E2D17880035128C /* OneDriveFileProvider.swift in Sources */,
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 				799396C81D48C02300086753 /* SMB2IOCtl.swift in Sources */,
 				799396D71D48C02300086753 /* SMB2Types.swift in Sources */,
+				7958155A1F478ED9003344DD /* HTTPFileProvider.swift in Sources */,
+				798654331E8874BC002FA550 /* FTPHelper.swift in Sources */,
 				7924B1B21D89FCDA00589DB7 /* FPSStreamTask.swift in Sources */,
 				799396C51D48C02300086753 /* SMB2FileOperation.swift in Sources */,
+				79BD63C81E2D17880035128C /* OneDriveHelper.swift in Sources */,
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 				799396CB1D48C02300086753 /* SMB2Query.swift in Sources */,
 				799396AA1D48C02300086753 /* DropboxFileProvider.swift in Sources */,
+				79BD638C1E2CC2300035128C /* ExtendedLocalFileProvider.swift in Sources */,
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@@ -431,14 +539,23 @@
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 				799396D51D48C02300086753 /* SMB2Tree.swift in Sources */,
 				7924B1A31D89DAE000589DB7 /* Options.swift in Sources */,
+				792572421DF23BDA006A1526 /* LocalHelper.swift in Sources */,
+				7936BC131E880F5700A6C81C /* FTPFileProvider.swift in Sources */,
+				79480FF71E3ABDD0007E7275 /* CloudFileProvider.swift in Sources */,
+				79F5745C1DFDB10B00179ABF /* FileObject.swift in Sources */,
+				79BD63C61E2D17880035128C /* OneDriveFileProvider.swift in Sources */,
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 				7924B19A1D89DAE000589DB7 /* Element.swift in Sources */,
 				799396C91D48C02300086753 /* SMB2IOCtl.swift in Sources */,
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 				799396D81D48C02300086753 /* SMB2Types.swift in Sources */,
 				799396C61D48C02300086753 /* SMB2FileOperation.swift in Sources */,
+				79BD63C91E2D17880035128C /* OneDriveHelper.swift in Sources */,
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 				794C220F1D591A4B00EC49B8 /* SMB2QueryTypes.swift in Sources */,
@@ -454,6 +571,7 @@
 				799396C31D48C02300086753 /* SMB2FileHandle.swift in Sources */,
 				799396CC1D48C02300086753 /* SMB2Query.swift in Sources */,
 				7924B1AD1D89F7D800589DB7 /* SMBClient.swift in Sources */,
+				79BD638D1E2CC2300035128C /* ExtendedLocalFileProvider.swift in Sources */,
 				799396AB1D48C02300086753 /* DropboxFileProvider.swift in Sources */,
 				7924B1A61D89DAE000589DB7 /* Parser.swift in Sources */,
 				799396B11D48C02300086753 /* FileProvider.swift in Sources */,
@@ -465,14 +583,23 @@
 			isa = PBXSourcesBuildPhase;
 			buildActionMask = 2147483647;
 			files = (
+				796807571E7BF17E00BBB87B /* FileProviderExtensions.swift in Sources */,
 				799396B51D48C02300086753 /* LocalFileProvider.swift in Sources */,
 				799396D61D48C02300086753 /* SMB2Tree.swift in Sources */,
 				7924B1A41D89DAE000589DB7 /* Options.swift in Sources */,
+				792572431DF23BDA006A1526 /* LocalHelper.swift in Sources */,
+				7936BC141E880F5700A6C81C /* FTPFileProvider.swift in Sources */,
+				79480FF81E3ABDD0007E7275 /* CloudFileProvider.swift in Sources */,
+				79F5745D1DFDB10B00179ABF /* FileObject.swift in Sources */,
+				79BD63C71E2D17880035128C /* OneDriveFileProvider.swift in Sources */,
 				7924B1B11D89F7DF00589DB7 /* FPSStreamTask.swift in Sources */,
 				7924B19B1D89DAE000589DB7 /* Element.swift in Sources */,
 				799396CA1D48C02300086753 /* SMB2IOCtl.swift in Sources */,
+				7958155C1F478ED9003344DD /* HTTPFileProvider.swift in Sources */,
+				79F4678C1E8B80F200C91A85 /* FTPHelper.swift in Sources */,
 				799396D91D48C02300086753 /* SMB2Types.swift in Sources */,
 				799396C71D48C02300086753 /* SMB2FileOperation.swift in Sources */,
+				79BD63CA1E2D17880035128C /* OneDriveHelper.swift in Sources */,
 				799396C11D48C02300086753 /* SMB2DataTypes.swift in Sources */,
 				799396BB1D48C02300086753 /* SMBFileProvider.swift in Sources */,
 				794C22101D591A4B00EC49B8 /* SMB2QueryTypes.swift in Sources */,
@@ -488,6 +615,7 @@
 				799396C41D48C02300086753 /* SMB2FileHandle.swift in Sources */,
 				799396CD1D48C02300086753 /* SMB2Query.swift in Sources */,
 				7924B1AE1D89F7D900589DB7 /* SMBClient.swift in Sources */,
+				79BD638E1E2CC2300035128C /* ExtendedLocalFileProvider.swift in Sources */,
 				799396AC1D48C02300086753 /* DropboxFileProvider.swift in Sources */,
 				7924B1A71D89DAE000589DB7 /* Parser.swift in Sources */,
 				799396B21D48C02300086753 /* FileProvider.swift in Sources */,
@@ -501,6 +629,7 @@
 		799396601D48B7BF00086753 /* Debug */ = {
 			isa = XCBuildConfiguration;
 			buildSettings = {
+				BUNDLE_VERSION_STRING = 0.20.0;
 				CLANG_WARN_BOOL_CONVERSION = YES;
 				CLANG_WARN_CONSTANT_CONVERSION = YES;
 				CLANG_WARN_EMPTY_BODY = YES;
@@ -510,9 +639,13 @@
 				CLANG_WARN_SUSPICIOUS_MOVE = YES;
 				CLANG_WARN_UNREACHABLE_CODE = YES;
 				CLANG_WARN__DUPLICATE_METHOD_MATCH = YES;
+				COPY_PHASE_STRIP = NO;
+				DEBUG_INFORMATION_FORMAT = dwarf;
+				ENABLE_BITCODE = YES;
 				ENABLE_STRICT_OBJC_MSGSEND = YES;
 				ENABLE_TESTABILITY = YES;
 				GCC_NO_COMMON_BLOCKS = YES;
+				GCC_OPTIMIZATION_LEVEL = 0;
 				GCC_WARN_64_TO_32_BIT_CONVERSION = YES;
 				GCC_WARN_ABOUT_RETURN_TYPE = YES;
 				GCC_WARN_UNDECLARED_SELECTOR = YES;
@@ -520,6 +653,7 @@
 				GCC_WARN_UNUSED_FUNCTION = YES;
 				GCC_WARN_UNUSED_VARIABLE = YES;
 				ONLY_ACTIVE_ARCH = YES;
+				PRODUCT_NAME = FilesProvider;
 				SWIFT_VERSION = 3.0;
 			};
 			name = Debug;
@@ -527,6 +661,7 @@
 		799396611D48B7BF00086753 /* Release */ = {
 			isa = XCBuildConfiguration;
 			buildSettings = {
+				BUNDLE_VERSION_STRING = 0.20.0;
 				CLANG_WARN_BOOL_CONVERSION = YES;
 				CLANG_WARN_CONSTANT_CONVERSION = YES;
 				CLANG_WARN_EMPTY_BODY = YES;
@@ -536,6 +671,8 @@
 				CLANG_WARN_SUSPICIOUS_MOVE = YES;
 				CLANG_WARN_UNREACHABLE_CODE = YES;
 				CLANG_WARN__DUPLICATE_METHOD_MATCH = YES;
+				DEBUG_INFORMATION_FORMAT = "dwarf-with-dsym";
+				ENABLE_BITCODE = YES;
 				ENABLE_STRICT_OBJC_MSGSEND = YES;
 				GCC_NO_COMMON_BLOCKS = YES;
 				GCC_WARN_64_TO_32_BIT_CONVERSION = YES;
@@ -544,6 +681,7 @@
 				GCC_WARN_UNINITIALIZED_AUTOS = YES;
 				GCC_WARN_UNUSED_FUNCTION = YES;
 				GCC_WARN_UNUSED_VARIABLE = YES;
+				PRODUCT_NAME = FilesProvider;
 				SWIFT_OPTIMIZATION_LEVEL = "-Owholemodule";
 				SWIFT_VERSION = 3.0;
 			};
@@ -555,8 +693,6 @@
 				ALWAYS_SEARCH_USER_PATHS = NO;
 				APPLICATION_EXTENSION_API_ONLY = YES;
 				CLANG_ANALYZER_NONNULL = YES;
-				CLANG_CXX_LANGUAGE_STANDARD = "gnu++0x";
-				CLANG_CXX_LIBRARY = "libc++";
 				CLANG_ENABLE_MODULES = YES;
 				CLANG_ENABLE_OBJC_ARC = YES;
 				CLANG_WARN_BOOL_CONVERSION = YES;
@@ -568,19 +704,15 @@
 				CLANG_WARN_OBJC_ROOT_CLASS = YES_ERROR;
 				CLANG_WARN_UNREACHABLE_CODE = YES;
 				CLANG_WARN__DUPLICATE_METHOD_MATCH = YES;
-				COPY_PHASE_STRIP = NO;
 				CURRENT_PROJECT_VERSION = 1;
-				DEBUG_INFORMATION_FORMAT = dwarf;
 				DEFINES_MODULE = YES;
 				DYLIB_COMPATIBILITY_VERSION = 1;
 				DYLIB_CURRENT_VERSION = 1;
 				DYLIB_INSTALL_NAME_BASE = "@rpath";
 				ENABLE_STRICT_OBJC_MSGSEND = YES;
 				ENABLE_TESTABILITY = YES;
-				GCC_C_LANGUAGE_STANDARD = gnu99;
 				GCC_DYNAMIC_NO_PIC = NO;
 				GCC_NO_COMMON_BLOCKS = YES;
-				GCC_OPTIMIZATION_LEVEL = 0;
 				GCC_PREPROCESSOR_DEFINITIONS = (
 					"DEBUG=1",
 					"$(inherited)",
@@ -596,9 +728,7 @@
 				IPHONEOS_DEPLOYMENT_TARGET = 8.0;
 				LD_RUNPATH_SEARCH_PATHS = "$(inherited) @executable_path/Frameworks @loader_path/Frameworks";
 				MTL_ENABLE_DEBUG_INFO = YES;
-				ONLY_ACTIVE_ARCH = YES;
-				PRODUCT_BUNDLE_IDENTIFIER = "com.mousavian.FileProvider-iOS";
-				PRODUCT_NAME = FileProvider;
+				PRODUCT_BUNDLE_IDENTIFIER = "com.mousavian.FilesProvider-iOS";
 				SDKROOT = iphoneos;
 				SKIP_INSTALL = YES;
 				SWIFT_OPTIMIZATION_LEVEL = "-Onone";
@@ -614,8 +744,6 @@
 				ALWAYS_SEARCH_USER_PATHS = NO;
 				APPLICATION_EXTENSION_API_ONLY = YES;
 				CLANG_ANALYZER_NONNULL = YES;
-				CLANG_CXX_LANGUAGE_STANDARD = "gnu++0x";
-				CLANG_CXX_LIBRARY = "libc++";
 				CLANG_ENABLE_MODULES = YES;
 				CLANG_ENABLE_OBJC_ARC = YES;
 				CLANG_WARN_BOOL_CONVERSION = YES;
@@ -627,16 +755,13 @@
 				CLANG_WARN_OBJC_ROOT_CLASS = YES_ERROR;
 				CLANG_WARN_UNREACHABLE_CODE = YES;
 				CLANG_WARN__DUPLICATE_METHOD_MATCH = YES;
-				COPY_PHASE_STRIP = NO;
 				CURRENT_PROJECT_VERSION = 1;
-				DEBUG_INFORMATION_FORMAT = "dwarf-with-dsym";
 				DEFINES_MODULE = YES;
 				DYLIB_COMPATIBILITY_VERSION = 1;
 				DYLIB_CURRENT_VERSION = 1;
 				DYLIB_INSTALL_NAME_BASE = "@rpath";
 				ENABLE_NS_ASSERTIONS = NO;
 				ENABLE_STRICT_OBJC_MSGSEND = YES;
-				GCC_C_LANGUAGE_STANDARD = gnu99;
 				GCC_NO_COMMON_BLOCKS = YES;
 				GCC_WARN_64_TO_32_BIT_CONVERSION = YES;
 				GCC_WARN_ABOUT_RETURN_TYPE = YES_ERROR;
@@ -649,8 +774,7 @@
 				IPHONEOS_DEPLOYMENT_TARGET = 8.0;
 				LD_RUNPATH_SEARCH_PATHS = "$(inherited) @executable_path/Frameworks @loader_path/Frameworks";
 				MTL_ENABLE_DEBUG_INFO = NO;
-				PRODUCT_BUNDLE_IDENTIFIER = "com.mousavian.FileProvider-iOS";
-				PRODUCT_NAME = FileProvider;
+				PRODUCT_BUNDLE_IDENTIFIER = "com.mousavian.FilesProvider-iOS";
 				SDKROOT = iphoneos;
 				SKIP_INSTALL = YES;
 				TARGETED_DEVICE_FAMILY = "1,2";
@@ -680,20 +804,17 @@
 				CLANG_WARN_UNREACHABLE_CODE = YES;
 				CLANG_WARN__DUPLICATE_METHOD_MATCH = YES;
 				COMBINE_HIDPI_IMAGES = YES;
-				COPY_PHASE_STRIP = NO;
 				CURRENT_PROJECT_VERSION = 1;
-				DEBUG_INFORMATION_FORMAT = dwarf;
 				DEFINES_MODULE = YES;
 				DYLIB_COMPATIBILITY_VERSION = 1;
 				DYLIB_CURRENT_VERSION = 1;
 				DYLIB_INSTALL_NAME_BASE = "@rpath";
+				ENABLE_BITCODE = NO;
 				ENABLE_STRICT_OBJC_MSGSEND = YES;
 				ENABLE_TESTABILITY = YES;
 				FRAMEWORK_VERSION = A;
-				GCC_C_LANGUAGE_STANDARD = gnu99;
 				GCC_DYNAMIC_NO_PIC = NO;
 				GCC_NO_COMMON_BLOCKS = YES;
-				GCC_OPTIMIZATION_LEVEL = 0;
 				GCC_PREPROCESSOR_DEFINITIONS = (
 					"DEBUG=1",
 					"$(inherited)",
@@ -709,9 +830,7 @@
 				LD_RUNPATH_SEARCH_PATHS = "$(inherited) @executable_path/../Frameworks @loader_path/Frameworks";
 				MACOSX_DEPLOYMENT_TARGET = 10.10;
 				MTL_ENABLE_DEBUG_INFO = YES;
-				ONLY_ACTIVE_ARCH = YES;
-				PRODUCT_BUNDLE_IDENTIFIER = "com.mousavian.FileProvider-OSX";
-				PRODUCT_NAME = FileProvider;
+				PRODUCT_BUNDLE_IDENTIFIER = "com.mousavian.FilesProvider-OSX";
 				SDKROOT = macosx;
 				SKIP_INSTALL = YES;
 				SWIFT_OPTIMIZATION_LEVEL = "-Onone";
@@ -740,17 +859,15 @@
 				CLANG_WARN_UNREACHABLE_CODE = YES;
 				CLANG_WARN__DUPLICATE_METHOD_MATCH = YES;
 				COMBINE_HIDPI_IMAGES = YES;
-				COPY_PHASE_STRIP = NO;
 				CURRENT_PROJECT_VERSION = 1;
-				DEBUG_INFORMATION_FORMAT = "dwarf-with-dsym";
 				DEFINES_MODULE = YES;
 				DYLIB_COMPATIBILITY_VERSION = 1;
 				DYLIB_CURRENT_VERSION = 1;
 				DYLIB_INSTALL_NAME_BASE = "@rpath";
+				ENABLE_BITCODE = NO;
 				ENABLE_NS_ASSERTIONS = NO;
 				ENABLE_STRICT_OBJC_MSGSEND = YES;
 				FRAMEWORK_VERSION = A;
-				GCC_C_LANGUAGE_STANDARD = gnu99;
 				GCC_NO_COMMON_BLOCKS = YES;
 				GCC_WARN_64_TO_32_BIT_CONVERSION = YES;
 				GCC_WARN_ABOUT_RETURN_TYPE = YES_ERROR;
@@ -763,8 +880,7 @@
 				LD_RUNPATH_SEARCH_PATHS = "$(inherited) @executable_path/../Frameworks @loader_path/Frameworks";
 				MACOSX_DEPLOYMENT_TARGET = 10.10;
 				MTL_ENABLE_DEBUG_INFO = NO;
-				PRODUCT_BUNDLE_IDENTIFIER = "com.mousavian.FileProvider-OSX";
-				PRODUCT_NAME = FileProvider;
+				PRODUCT_BUNDLE_IDENTIFIER = "com.mousavian.FilesProvider-OSX";
 				SDKROOT = macosx;
 				SKIP_INSTALL = YES;
 				VERSIONING_SYSTEM = "apple-generic";
@@ -791,19 +907,16 @@
 				CLANG_WARN_OBJC_ROOT_CLASS = YES_ERROR;
 				CLANG_WARN_UNREACHABLE_CODE = YES;
 				CLANG_WARN__DUPLICATE_METHOD_MATCH = YES;
-				COPY_PHASE_STRIP = NO;
+				"CODE_SIGN_IDENTITY[sdk=appletvos*]" = "";
 				CURRENT_PROJECT_VERSION = 1;
-				DEBUG_INFORMATION_FORMAT = dwarf;
 				DEFINES_MODULE = YES;
 				DYLIB_COMPATIBILITY_VERSION = 1;
 				DYLIB_CURRENT_VERSION = 1;
 				DYLIB_INSTALL_NAME_BASE = "@rpath";
 				ENABLE_STRICT_OBJC_MSGSEND = YES;
 				ENABLE_TESTABILITY = YES;
-				GCC_C_LANGUAGE_STANDARD = gnu99;
 				GCC_DYNAMIC_NO_PIC = NO;
 				GCC_NO_COMMON_BLOCKS = YES;
-				GCC_OPTIMIZATION_LEVEL = 0;
 				GCC_PREPROCESSOR_DEFINITIONS = (
 					"DEBUG=1",
 					"$(inherited)",
@@ -818,9 +931,7 @@
 				INSTALL_PATH = "$(LOCAL_LIBRARY_DIR)/Frameworks";
 				LD_RUNPATH_SEARCH_PATHS = "$(inherited) @executable_path/Frameworks @loader_path/Frameworks";
 				MTL_ENABLE_DEBUG_INFO = YES;
-				ONLY_ACTIVE_ARCH = YES;
-				PRODUCT_BUNDLE_IDENTIFIER = "com.mousavian.FileProvider-tvOS";
-				PRODUCT_NAME = FileProvider;
+				PRODUCT_BUNDLE_IDENTIFIER = "com.mousavian.FilesProvider-tvOS";
 				SDKROOT = appletvos;
 				SKIP_INSTALL = YES;
 				SWIFT_OPTIMIZATION_LEVEL = "-Onone";
@@ -850,16 +961,14 @@
 				CLANG_WARN_OBJC_ROOT_CLASS = YES_ERROR;
 				CLANG_WARN_UNREACHABLE_CODE = YES;
 				CLANG_WARN__DUPLICATE_METHOD_MATCH = YES;
-				COPY_PHASE_STRIP = NO;
+				"CODE_SIGN_IDENTITY[sdk=appletvos*]" = "";
 				CURRENT_PROJECT_VERSION = 1;
-				DEBUG_INFORMATION_FORMAT = "dwarf-with-dsym";
 				DEFINES_MODULE = YES;
 				DYLIB_COMPATIBILITY_VERSION = 1;
 				DYLIB_CURRENT_VERSION = 1;
 				DYLIB_INSTALL_NAME_BASE = "@rpath";
 				ENABLE_NS_ASSERTIONS = NO;
 				ENABLE_STRICT_OBJC_MSGSEND = YES;
-				GCC_C_LANGUAGE_STANDARD = gnu99;
 				GCC_NO_COMMON_BLOCKS = YES;
 				GCC_WARN_64_TO_32_BIT_CONVERSION = YES;
 				GCC_WARN_ABOUT_RETURN_TYPE = YES_ERROR;
@@ -871,8 +980,7 @@
 				INSTALL_PATH = "$(LOCAL_LIBRARY_DIR)/Frameworks";
 				LD_RUNPATH_SEARCH_PATHS = "$(inherited) @executable_path/Frameworks @loader_path/Frameworks";
 				MTL_ENABLE_DEBUG_INFO = NO;
-				PRODUCT_BUNDLE_IDENTIFIER = "com.mousavian.FileProvider-tvOS";
-				PRODUCT_NAME = FileProvider;
+				PRODUCT_BUNDLE_IDENTIFIER = "com.mousavian.FilesProvider-tvOS";
 				SDKROOT = appletvos;
 				SKIP_INSTALL = YES;
 				TARGETED_DEVICE_FAMILY = 3;
@@ -886,7 +994,7 @@
 /* End XCBuildConfiguration section */

 /* Begin XCConfigurationList section */
-		7993965F1D48B7BF00086753 /* Build configuration list for PBXProject "FileProvider" */ = {
+		7993965F1D48B7BF00086753 /* Build configuration list for PBXProject "FilesProvider" */ = {
 			isa = XCConfigurationList;
 			buildConfigurations = (
 				799396601D48B7BF00086753 /* Debug */,
@@ -895,7 +1003,7 @@
 			defaultConfigurationIsVisible = 0;
 			defaultConfigurationName = Release;
 		};
-		7993966F1D48B7F600086753 /* Build configuration list for PBXNativeTarget "FileProvider iOS" */ = {
+		7993966F1D48B7F600086753 /* Build configuration list for PBXNativeTarget "FilesProvider iOS" */ = {
 			isa = XCConfigurationList;
 			buildConfigurations = (
 				7993966D1D48B7F600086753 /* Debug */,
@@ -904,7 +1012,7 @@
 			defaultConfigurationIsVisible = 0;
 			defaultConfigurationName = Release;
 		};
-		7993967A1D48B80D00086753 /* Build configuration list for PBXNativeTarget "FileProvider OSX" */ = {
+		7993967A1D48B80D00086753 /* Build configuration list for PBXNativeTarget "FilesProvider OSX" */ = {
 			isa = XCConfigurationList;
 			buildConfigurations = (
 				7993967B1D48B80D00086753 /* Debug */,
@@ -913,7 +1021,7 @@
 			defaultConfigurationIsVisible = 0;
 			defaultConfigurationName = Release;
 		};
-		799396871D48B82700086753 /* Build configuration list for PBXNativeTarget "FileProvider tvOS" */ = {
+		799396871D48B82700086753 /* Build configuration list for PBXNativeTarget "FilesProvider tvOS" */ = {
 			isa = XCConfigurationList;
 			buildConfigurations = (
 				799396881D48B82700086753 /* Debug */,
@@ -1,6 +1,6 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <Scheme
-   LastUpgradeVersion = "0800"
+   LastUpgradeVersion = "0820"
   version = "1.3">
   <BuildAction
      parallelizeBuildables = "YES"
@@ -15,9 +15,9 @@
            <BuildableReference
               BuildableIdentifier = "primary"
               BlueprintIdentifier = "799396741D48B80D00086753"
-               BuildableName = "FileProvider.framework"
-               BlueprintName = "FileProvider OSX"
-               ReferencedContainer = "container:FileProvider.xcodeproj">
+               BuildableName = "FilesProvider.framework"
+               BlueprintName = "FilesProvider OSX"
+               ReferencedContainer = "container:FilesProvider.xcodeproj">
            </BuildableReference>
         </BuildActionEntry>
      </BuildActionEntries>
@@ -26,6 +26,7 @@
      buildConfiguration = "Debug"
      selectedDebuggerIdentifier = "Xcode.DebuggerFoundation.Debugger.LLDB"
      selectedLauncherIdentifier = "Xcode.DebuggerFoundation.Launcher.LLDB"
+      language = ""
      shouldUseLaunchSchemeArgsEnv = "YES">
      <Testables>
      </Testables>
@@ -36,6 +37,7 @@
      buildConfiguration = "Debug"
      selectedDebuggerIdentifier = "Xcode.DebuggerFoundation.Debugger.LLDB"
      selectedLauncherIdentifier = "Xcode.DebuggerFoundation.Launcher.LLDB"
+      language = ""
      launchStyle = "0"
      useCustomWorkingDirectory = "NO"
      ignoresPersistentStateOnLaunch = "NO"
@@ -46,9 +48,9 @@
         <BuildableReference
            BuildableIdentifier = "primary"
            BlueprintIdentifier = "799396741D48B80D00086753"
-            BuildableName = "FileProvider.framework"
-            BlueprintName = "FileProvider OSX"
-            ReferencedContainer = "container:FileProvider.xcodeproj">
+            BuildableName = "FilesProvider.framework"
+            BlueprintName = "FilesProvider OSX"
+            ReferencedContainer = "container:FilesProvider.xcodeproj">
         </BuildableReference>
      </MacroExpansion>
      <AdditionalOptions>
@@ -64,9 +66,9 @@
         <BuildableReference
            BuildableIdentifier = "primary"
            BlueprintIdentifier = "799396741D48B80D00086753"
-            BuildableName = "FileProvider.framework"
-            BlueprintName = "FileProvider OSX"
-            ReferencedContainer = "container:FileProvider.xcodeproj">
+            BuildableName = "FilesProvider.framework"
+            BlueprintName = "FilesProvider OSX"
+            ReferencedContainer = "container:FilesProvider.xcodeproj">
         </BuildableReference>
      </MacroExpansion>
   </ProfileAction>
@@ -1,6 +1,6 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <Scheme
-   LastUpgradeVersion = "0800"
+   LastUpgradeVersion = "0820"
   version = "1.3">
   <BuildAction
      parallelizeBuildables = "YES"
@@ -15,9 +15,9 @@
            <BuildableReference
               BuildableIdentifier = "primary"
               BlueprintIdentifier = "799396661D48B7F600086753"
-               BuildableName = "FileProvider.framework"
-               BlueprintName = "FileProvider iOS"
-               ReferencedContainer = "container:FileProvider.xcodeproj">
+               BuildableName = "FilesProvider.framework"
+               BlueprintName = "FilesProvider iOS"
+               ReferencedContainer = "container:FilesProvider.xcodeproj">
            </BuildableReference>
         </BuildActionEntry>
      </BuildActionEntries>
@@ -26,6 +26,7 @@
      buildConfiguration = "Debug"
      selectedDebuggerIdentifier = "Xcode.DebuggerFoundation.Debugger.LLDB"
      selectedLauncherIdentifier = "Xcode.DebuggerFoundation.Launcher.LLDB"
+      language = ""
      shouldUseLaunchSchemeArgsEnv = "YES">
      <Testables>
      </Testables>
@@ -36,6 +37,7 @@
      buildConfiguration = "Debug"
      selectedDebuggerIdentifier = "Xcode.DebuggerFoundation.Debugger.LLDB"
      selectedLauncherIdentifier = "Xcode.DebuggerFoundation.Launcher.LLDB"
+      language = ""
      launchStyle = "0"
      useCustomWorkingDirectory = "NO"
      ignoresPersistentStateOnLaunch = "NO"
@@ -46,9 +48,9 @@
         <BuildableReference
            BuildableIdentifier = "primary"
            BlueprintIdentifier = "799396661D48B7F600086753"
-            BuildableName = "FileProvider.framework"
-            BlueprintName = "FileProvider iOS"
-            ReferencedContainer = "container:FileProvider.xcodeproj">
+            BuildableName = "FilesProvider.framework"
+            BlueprintName = "FilesProvider iOS"
+            ReferencedContainer = "container:FilesProvider.xcodeproj">
         </BuildableReference>
      </MacroExpansion>
      <AdditionalOptions>
@@ -64,9 +66,9 @@
         <BuildableReference
            BuildableIdentifier = "primary"
            BlueprintIdentifier = "799396661D48B7F600086753"
-            BuildableName = "FileProvider.framework"
-            BlueprintName = "FileProvider iOS"
-            ReferencedContainer = "container:FileProvider.xcodeproj">
+            BuildableName = "FilesProvider.framework"
+            BlueprintName = "FilesProvider iOS"
+            ReferencedContainer = "container:FilesProvider.xcodeproj">
         </BuildableReference>
      </MacroExpansion>
   </ProfileAction>
@@ -1,6 +1,6 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <Scheme
-   LastUpgradeVersion = "0800"
+   LastUpgradeVersion = "0810"
   version = "1.3">
   <BuildAction
      parallelizeBuildables = "YES"
@@ -15,9 +15,9 @@
            <BuildableReference
               BuildableIdentifier = "primary"
               BlueprintIdentifier = "799396811D48B82700086753"
-               BuildableName = "FileProvider.framework"
-               BlueprintName = "FileProvider tvOS"
-               ReferencedContainer = "container:FileProvider.xcodeproj">
+               BuildableName = "FilesProvider.framework"
+               BlueprintName = "FilesProvider tvOS"
+               ReferencedContainer = "container:FilesProvider.xcodeproj">
            </BuildableReference>
         </BuildActionEntry>
      </BuildActionEntries>
@@ -26,6 +26,7 @@
      buildConfiguration = "Debug"
      selectedDebuggerIdentifier = "Xcode.DebuggerFoundation.Debugger.LLDB"
      selectedLauncherIdentifier = "Xcode.DebuggerFoundation.Launcher.LLDB"
+      language = ""
      shouldUseLaunchSchemeArgsEnv = "YES">
      <Testables>
      </Testables>
@@ -36,6 +37,7 @@
      buildConfiguration = "Debug"
      selectedDebuggerIdentifier = "Xcode.DebuggerFoundation.Debugger.LLDB"
      selectedLauncherIdentifier = "Xcode.DebuggerFoundation.Launcher.LLDB"
+      language = ""
      launchStyle = "0"
      useCustomWorkingDirectory = "NO"
      ignoresPersistentStateOnLaunch = "NO"
@@ -46,9 +48,9 @@
         <BuildableReference
            BuildableIdentifier = "primary"
            BlueprintIdentifier = "799396811D48B82700086753"
-            BuildableName = "FileProvider.framework"
-            BlueprintName = "FileProvider tvOS"
-            ReferencedContainer = "container:FileProvider.xcodeproj">
+            BuildableName = "FilesProvider.framework"
+            BlueprintName = "FilesProvider tvOS"
+            ReferencedContainer = "container:FilesProvider.xcodeproj">
         </BuildableReference>
      </MacroExpansion>
      <AdditionalOptions>
@@ -64,9 +66,9 @@
         <BuildableReference
            BuildableIdentifier = "primary"
            BlueprintIdentifier = "799396811D48B82700086753"
-            BuildableName = "FileProvider.framework"
-            BlueprintName = "FileProvider tvOS"
-            ReferencedContainer = "container:FileProvider.xcodeproj">
+            BuildableName = "FilesProvider.framework"
+            BlueprintName = "FilesProvider tvOS"
+            ReferencedContainer = "container:FilesProvider.xcodeproj">
         </BuildableReference>
      </MacroExpansion>
   </ProfileAction>
@@ -1,6 +1,6 @@
 The MIT License (MIT)

-Copyright (c) 2016 Amir Abbas Mousavian
+Copyright (c) 2016-17 Amir Abbas Mousavian

 Permission is hereby granted, free of charge, to any person obtaining a copy
 of this software and associated documentation files (the "Software"), to deal
@@ -1,5 +1,5 @@
 import PackageDescription

 let package = Package(
-    name: "FileProvider"
-)
+    name: "FilesProvider"
+)
@@ -15,7 +15,7 @@
 	<key>CFBundlePackageType</key>
 	<string>FMWK</string>
 	<key>CFBundleShortVersionString</key>
-	<string>0.3.0</string>
+	<string>${BUNDLE_VERSION_STRING}</string>
 	<key>CFBundleSignature</key>
 	<string>????</string>
 	<key>CFBundleVersion</key>
@@ -15,7 +15,7 @@
 	<key>CFBundlePackageType</key>
 	<string>FMWK</string>
 	<key>CFBundleShortVersionString</key>
-	<string>0.3.0</string>
+	<string>${BUNDLE_VERSION_STRING}</string>
 	<key>CFBundleSignature</key>
 	<string>????</string>
 	<key>CFBundleVersion</key>
@@ -15,7 +15,7 @@
 	<key>CFBundlePackageType</key>
 	<string>FMWK</string>
 	<key>CFBundleShortVersionString</key>
-	<string>0.3.0</string>
+	<string>${BUNDLE_VERSION_STRING}</string>
 	<key>CFBundleSignature</key>
 	<string>????</string>
 	<key>CFBundleVersion</key>
@@ -1,69 +1,109 @@
-# FileProvider
+![File Provider](fileprovider.png)

 >This Swift library provide a swifty way to deal with local and remote files and directories in a unified way.

-[![Swift Version][swift-image]][swift-url]
-[![License][license-image]][license-url]
-[![Platform](https://img.shields.io/badge/Platform-iOS%2C%20macOS%2C%20tvOS-lightgray.svg)]()
+<center>

+[![Swift Version][swift-image]][swift-url]
+[![Platform][platform-image]](#)
+[![License][license-image]][license-url]
 [![Build Status][travis-image]][travis-url]
-[![CocoaPods Compatible](https://img.shields.io/cocoapods/v/FileProvider.svg)](https://cocoapods.org/pods/FileProvider)
-[![codebeat badge][codebeat-image]][codebeat-url]
+[![Codebeat Badge][codebeat-image]][codebeat-url]
+
+[![Release version][release-image]][release-url]
+[![CocoaPods version](https://img.shields.io/cocoapods/v/FilesProvider.svg)][cocoapods]
+[![Carthage compatible][carthage-image]](https://github.com/Carthage/Carthage)
+[![Cocoapods Downloads][cocoapods-downloads]][cocoapods]
+[![Cocoapods Apps][cocoapods-apps]][cocoapods]
+
+Old Cocoapods repo stats:
+[![Cocoapods Downloads][cocoapods-downloads-old]][cocoapods-old]
+[![Cocoapods Apps][cocoapods-apps-old]][cocoapods-old]
+
+</center>

 <!--- 
-
-[![codecov](https://codecov.io/gh/amosavian/FileProvider/branch/master/graph/badge.svg)](https://codecov.io/gh/amosavian/FileProvider)
-[![Carthage compatible](https://img.shields.io/badge/Carthage-compatible-4BC51D.svg?style=flat)](https://github.com/Carthage/Carthage) 
+[![Cocoapods Doc][docs-image]][docs-url]
+[![codecov](https://codecov.io/gh/amosavian/FileProvider/branch/master/graph/badge.svg)](https://codecov.io/gh/amosavian/FileProvider) 
 ---> 

-This library provides implementaion of WebDav and SMB2 (incomplete) and local files.
+This library provides implementaion of WebDav, FTP, Dropbox, OneDrive and SMB2 (incomplete) and local files.

-All functions are async calls and it wont block your main thread.
-
-Local and WebDAV providers are fully tested and can be used in production environment.
+All functions do async calls and it wont block your main thread.

 ## Features

- [x] **LocalFileProvider** a wrapper around `FileManager` with some additions like searching and reading a portion of file.
- [x] **WebDAVFileProvider** WebDAV protocol is defacto file transmission standard, replaced FTP.
- [x] **DropboxFileProvider** A wrapper around Dropbox Web API. For now it has limitation in uploading files up to 150MB.
- [ ] **SMBFileProvider** SMB2/3 introduced in 2006, which is a file and printer sharing protocol originated from Microsoft Windows and now is replacing AFP protocol on MacOS. I implemented data types and some basic functions but *main interface is not implemented yet!* SMB1/CIFS is depericated and very tricky to be implemented
- [ ] **FTPFileProvider** while deprecated in 1990s, it's still in use on some Web hosts.
- [ ] **AmazonS3FileProvider** 
+- [x] **LocalFileProvider** a wrapper around `FileManager` with some additions like builtin coordinating, searching and reading a portion of file.
+- [x] **CloudFileProvider** A wrapper around app's ubiquitous container API of iCloud Drive.
+- [x] **WebDAVFileProvider** WebDAV protocol is defacto file transmission standard, supported by some cloud services like `ownCloud`, `Box.com` and `Yandex.disk`.
+- [x] **FTPFileProvider** While deprecated in 1990s due to serious security concerns, it's still in use on some Web hosts.
+- [x] **DropboxFileProvider** A wrapper around Dropbox Web API.
+    * For now it has limitation in uploading files up to 150MB.
+- [x] **OneDriveFileProvider** A wrapper around OneDrive REST API, works with `onedrive.com` and compatible (business) servers.
+    * For now it has limitation in uploading files up to 100MB.
+- [ ] **GoogleFileProvider** A wrapper around Goodle Drive REST API.
+- [ ] **AmazonS3FileProvider** Amazon storage backend. Used by many sites.
+- [ ] **SMBFileProvider** SMB2/3 introduced in 2006, which is a file and printer sharing protocol originated from Microsoft Windows and now is replacing AFP protocol on macOS.
+    * Data types and some basic functions are implemented but *main interface is not implemented yet!*.
+    * SMBv1/CIFS is insecure, deprecated and kinda tricky to be implemented due to strict memory allignment in Swift.

 ## Requirements

- **Swift 3**
+- **Swift 3.0 or higher**
 - iOS 8.0 , OSX 10.10
 - XCode 8.0

-Legacy version is available in swift-2 branch
+Legacy version is available in swift-2 branch.

 ## Installation

-### Cocoapods / Carthage / Swift Package Manager
+### Important: this library has been renamed to avoid conflict in iOS 11, macOS 10.13 and Xcode 9.0. Please read issue [#53](https://github.com/amosavian/FileProvider/issues/53) to find more.

-FileProvider supports both CocoaPods. 
+
+### Cocoapods / Carthage / Swift Package Manager

 Add this line to your pods file:

-	pod "FileProvider"
+```ruby
+pod "FilesProvider"
+```
+
+Or add this to Cartfile:
+
+```
+github "amosavian/FileProvider"
+```
+
+Or to use in Swift Package Manager add this line in `Dependencies`:
+
+```swift
+.Package(url: "https://github.com/amosavian/FileProvider.git", majorVersion: 0)
+```
+
+### Manually

-### Git
 To have latest updates with ease, use this command on terminal to get a clone:

-	git clone https://github.com/amosavian/FileProvider FileProvider
-	
+```bash
+git clone https://github.com/amosavian/FileProvider
+```
+
 You can update your library using this command in FileProvider folder:

-	git pull
+```bash
+git pull
+```

 if you have a git based project, use this command in your projects directory to add this project as a submodule to your project:

-	git submodule add https://github.com/amosavian/FileProvider FileProvider
+```bash
+git submodule add https://github.com/amosavian/FileProvider
+```
+Then you can do either:

-### Manually
-Copy Source folder to your project and Voila!
+* Copy Source folder to your project and Voila!
+
+* Drop `FilesProvider.xcodeproj` to you Xcode workspace and add the framework to your Embeded Binaries in target.

 ## Usage

@@ -73,71 +113,100 @@ Each provider has a specific class which conforms to FileProvider protocol and s

 For LocalFileProvider if you want to deal with `Documents` folder

-	let documentsProvider = LocalFileProvider()
+```	swift
+import FilesProvider

-is equal to:
-	    
-	let documentPath = NSSearchPathForDirectoriesInDomains(NSSearchPathDirectory.DocumentDirectory, NSSearchPathDomainMask.UserDomainMask, true);
-	let documentsURL = URL(fileURLWithPath: documentPath);
-	let documentsProvider = LocalFileProvider(baseURL: documentsURL)
+let documentsProvider = LocalFileProvider()
+
+// Equals with:
+let documentsProvider = LocalFileProvider(for: .documentDirectory, in: .userDomainMask)
+
+// Equals with:
+let documentsURL = FileManager.default.urls(for: .documentDirectory, in: .userDomainMask).first!
+let documentsProvider = LocalFileProvider(baseURL: documentsURL)
+```
+
+Also for using group shared container:
+
+```swift
+import FilesProvider
+
+let documentsProvider = LocalFileProvider(sharedContainerId: "group.yourcompany.appContainer")
+// Replace your group identifier
+```

 You can't change the base url later. and all paths are related to this base url by default.

+To initialize an iCloud Container provider look at [here](https://medium.com/ios-os-x-development/icloud-drive-documents-1a46b5706fe1) to see how to update project settings then use below code, This will automatically manager creating Documents folder in container:
+
+```swift
+import FilesProvider
+
+let documentsProvider = CloudFileProvider(containerId: nil)
+```
+
+
 For remote file providers authentication may be necessary:

-	let credential = URLCredential(user: "user", password: "pass", persistence: .permanent)
-	let webdavProvider = WebDAVFileProvider(baseURL: URL(string: "http://www.example.com/dav")!, credential: credential)
+```	swift
+import FilesProvider
+
+let credential = URLCredential(user: "user", password: "pass", persistence: .permanent)
+let webdavProvider = WebDAVFileProvider(baseURL: URL(string: "http://www.example.com/dav")!, credential: credential)
+```

 * In case you want to connect non-secure servers for WebDAV (http) in iOS 9+ / macOS 10.11+ you should disable App Transport Security (ATS) according to [this guide.](https://gist.github.com/mlynch/284699d676fe9ed0abfa)

-* For Dropbox, user is clientID and password is Token which both must be retrieved via [OAuth2 API of Dropbox](https://www.dropbox.com/developers/reference/oauth-guide). There are libraries like [p2/OAuth2](https://github.com/p2/OAuth2) or [OAuthSwift](https://github.com/OAuthSwift/OAuthSwift) which can facilate the procedure to retrieve token.
+* For Dropbox & OneDrive, user is clientID and password is Token which both must be retrieved via [OAuth2 API of Dropbox](https://www.dropbox.com/developers/reference/oauth-guide). There are libraries like [p2/OAuth2](https://github.com/p2/OAuth2) or [OAuthSwift](https://github.com/OAuthSwift/OAuthSwift) which can facilate the procedure to retrieve token. The latter is easier to use and prefered.
 	
 For interaction with UI, set delegate variable of `FileProvider` object

-You can use `absoluteURL()` method if provider to get direct access url (local or remote files) for some file systems which allows to do so (Dropbox doesn't support and returns path simply wrapped in URL)
+You can use `url(of:)` method if provider to get direct access url (local or remote files) for some file systems which allows to do so (Dropbox doesn't support and returns path simply wrapped in URL)

 ### Delegates

 For updating User interface please consider using delegate method instead of completion handlers. Delegate methods are guaranteed to run in main thread to avoid bugs.

-It's simply three method which indicated whether the operation failed, succeed and how much of operation has been done (suitable for uploading and downloading operations).
+There's simply three method which indicated whether the operation failed, succeed and how much of operation has been done (suitable for uploading and downloading operations).

 Your class should conforms `FileProviderDelegate` class:

-	override func viewDidLoad() {
-		documentsProvider.delegate = self as FileProviderDelegate
-	}
+```swift
+override func viewDidLoad() {
+	documentsProvider.delegate = self as FileProviderDelegate
+}
 	
-	func fileproviderSucceed(_ fileProvider: FileProviderOperations, operation: FileOperation) {
-		switch operation {
-		case .copy(source: let source, destination: let dest):
-			print("\(source) copied to \(dest).")
-		case .remove(path: let path):
-			print("\(path) has been deleted.")
-		default:
-			break
-		}
+func fileproviderSucceed(_ fileProvider: FileProviderOperations, operation: FileOperationType) {
+	switch operation {
+	case .copy(source: let source, destination: let dest):
+		print("\(source) copied to \(dest).")
+	case .remove(path: let path):
+		print("\(path) has been deleted.")
+	default:
+		print("\(operation.actionDescription) from \(operation.source!) to \(operation.destination) succeed")
 	}
-	
-    func fileproviderFailed(_ fileProvider: FileProviderOperations, operation: FileOperation) {
-    	switch operation {
-		case .copy(source: let source, destination: let dest):
-			print("copy of \(source) failed.")
-		case .remove(path: let path):
-			print("\(path) can't be deleted.")
-		default:
-			break
-		}
-    }
-	
-    func fileproviderProgress(_ fileProvider: FileProviderOperations, operation: FileOperation, progress: Float) {
-		switch operation {
-		case .copy(source: let source, destination: let dest):
-			print("Copy\(source) to \(dest): \(progress * 100) completed.")
-		default:
-			break
-		}
+}
+
+func fileproviderFailed(_ fileProvider: FileProviderOperations, operation: FileOperationType) {
+    switch operation {
+	case .copy(source: let source, destination: let dest):
+		print("copy of \(source) failed.")
+	case .remove:
+		print("file can't be deleted.")
+	default:
+		print("\(operation.actionDescription) from \(operation.source!) to \(operation.destination) failed")
 	}
+}
+	
+func fileproviderProgress(_ fileProvider: FileProviderOperations, operation: FileOperationType, progress: Float) {
+	switch operation {
+	case .copy(source: let source, destination: let dest):
+		print("Copy\(source) to \(dest): \(progress * 100) completed.")
+	default:
+		break
+	}
+}
+```

 **Note:** `fileproviderProgress()` delegate method is not called by `LocalFileProvider` currently. 

@@ -151,7 +220,7 @@ You can also implement `FileOperationDelegate` protocol to control behaviour of

 `fileProvider(shouldProceedAfterError:, operation:)` will be called if an error occured during file operations. Return `true` if you want to continue operation on next files or `false` if you want stop operation further. Default value is false if you don't implement delegate.

-**Note: these methods will be called for files in a directory and its subfolders recursively.**
+**Note: In `LocalFileProvider`, these methods will be called for files in a directory and its subfolders recursively.**

 ### Directory contents and file attributes

@@ -159,124 +228,252 @@ There is a `FileObject` class which holds file attributes like size and creation

 For a single file:

-	documentsProvider.attributesOfItem(path: "/file.txt", completionHandler: {
-	    (attributes: LocalFileObject?, error: ErrorType?) -> Void in
-		if let attributes = attributes {
-			print("File Size: \(attributes.size)")
-			print("Creation Date: \(attributes.createdDate)")
-			print("Modification Date: \(attributes.modifiedDate)")
-			print("Is Read Only: \(attributes.isReadOnly)")
-		}
-	})
+```swift
+documentsProvider.attributesOfItem(path: "/file.txt", completionHandler: {
+	attributes, error in
+	if let attributes = attributes {
+		print("File Size: \(attributes.size)")
+		print("Creation Date: \(attributes.creationDate)")
+		print("Modification Date: \(attributes.modifiedDate)")
+		print("Is Read Only: \(attributes.isReadOnly)")
+	}
+})
+```

 To get list of files in a directory:

-	documentsProvider.contentsOfDirectory(path: "/", 	completionHandler: {
-	    (contents: [LocalFileObject], error: ErrorType?) -> Void in
-		for file in contents {
-			print("Name: \(attributes.name)")
-			print("Size: \(attributes.size)")
-			print("Creation Date: \(attributes.createdDate)")
-			print("Modification Date: \(attributes.modifiedDate)")
-		}
-	})
+```swift
+documentsProvider.contentsOfDirectory(path: "/", completionHandler: {
+	contents, error in
+	for file in contents {
+		print("Name: \(file.name)")
+		print("Size: \(file.size)")
+		print("Creation Date: \(file.creationDate)")
+		print("Modification Date: \(file.modifiedDate)")
+	}
+})
+```

 To get size of strage and used/free space:

-	func storageProperties(completionHandler: {(total: Int64, used: Int64) -> Void in
-	    print("Total Storage Space: \(total)")
-	    print("Used Space: \(used)")
-	    print("Free Space: \(total - used)")
-	})
+```swift
+func storageProperties(completionHandler: { total, used in
+	print("Total Storage Space: \(total)")
+	print("Used Space: \(used)")
+	print("Free Space: \(total - used)")
+})
+```
 	
 * if this function is unavailable on provider or an error has been occurred, total space will be reported `-1` and used space `0`

-### Change current directory
-
-	documentsProvider.currentPath = "/New Folder"
-	// now path is ~/Documents/New Folder
-	
-You can then pass "" (empty string) to `contentsOfDirectory` method to list files in current directory.
-
 ### Creating File and Folders

 Creating new directory:

-	documentsProvider.create(folder: "new folder", at: "/", completionHandler: nil)
+```swift
+documentsProvider.create(folder: "new folder", at: "/", completionHandler: { error in
+    if let error = error {
+        // Error handling here
+    } else {
+        // The operation succeed
+    }
+})
+```

-Creating new file from data stream:
-
-	let data = "hello world!".data(encoding: String.encoding.utf8)
-	let file = FileObject(name: "old.txt", createdDate: Date(), modifiedDate: Date(), isHidden: false, isReadOnly: true)
-	documentsProvider.create(file: file, at: "/", contents: data, completionHandler: nil)
+To create a file, use `writeContents(path:, content:, atomically:, completionHandler:)` method.

 ### Copy and Move/Rename Files

 Copy file old.txt to new.txt in current path:

-	documentsProvider.copyItem(path: "new folder/old.txt", to: "new.txt", overwrite: false, completionHandler: nil)
+```swift
+documentsProvider.copyItem(path: "new folder/old.txt", to: "new.txt", overwrite: false, completionHandler: nil)
+```

 Move file old.txt to new.txt in current path:

-	documentsProvider.moveItem(path: "new folder/old.txt", to: "new.txt", overwrite: false, completionHandler: nil)
+```swift
+documentsProvider.moveItem(path: "new folder/old.txt", to: "new.txt", overwrite: false, completionHandler: nil)
+```

-**Note:** To have a consistent behaviour, create intermediate directories first if necessary.
+**Note:** To have a consistent behavior, create intermediate directories first if necessary.

 ### Delete Files

-	documentsProvider.removeItem(path: "new.txt", completionHandler: nil)
+```swift
+documentsProvider.removeItem(path: "new.txt", completionHandler: nil)
+```

-***Caution:*** This method will delete directories with all it's content recursively.
+### Fetching Contents of File

-### Retrieve Content of File
+There is two method for this purpose, one of them loads entire file into `Data` and another can load a portion of file.

-There is two method for this purpose, one of them loads entire file into NSData and another can load a portion of file.
-
-	documentsProvider.contents(path: "old.txt", completionHandler: {
-		(contents: Data?, error: ErrorType?) -> Void
-		if let contents = contents {
-			print(String(data: contents, encoding: String.encoding.utf8)) // "hello world!"
-		}
-	})
+```swift
+documentsProvider.contents(path: "old.txt", completionHandler: {
+	contents, error in
+	if let contents = contents {
+		print(String(data: contents, encoding: .utf8)) // "hello world!"
+	}
+})
+```
 	
 If you want to retrieve a portion of file you can use `contents` method with offset and length arguments. Please note first byte of file has offset: 0.

-	documentsProvider.contents(path: "old.txt", offset: 2, length: 5, completionHandler: {
-		(contents: Data?, error: ErrorType?) -> Void
-		if let contents = contents {
-			print(String(data: contents, encoding: String.encoding.utf8)) // "llo w"
-		}
-	})
+```swift
+documentsProvider.contents(path: "old.txt", offset: 2, length: 5, completionHandler: {
+	contents, error in
+	if let contents = contents {
+		print(String(data: contents, encoding: .utf8)) // "llo w"
+	}
+})
+```

 ### Write Data To Files

-	let data = "What's up Newyork!".data(encoding: String.encoding.utf8)
-	documentsProvider.writeContents(path: "old.txt", content: data, atomically: true, completionHandler: nil)
+```swift
+let data = "What's up Newyork!".data(encoding: .utf8)
+documentsProvider.writeContents(path: "old.txt", content: data, atomically: true, completionHandler: nil)
+```

-### Operation Handle
+### Copying Files to and From Local Storage

-Creating/Copying/Deleting functions return a `OperationHandle` for remote operations. It provides progress and a `.cancel()` method which allows you to cancel operation in midst.
+There are two methods to download and upload files between provider's and local storage. These methods use `URLSessionDownloadTask` and `URLSessionUploadTask` classes and allows to use background session and provide progress via delegate.

-It's not supported by native `(NS)FileManager` so `LocalFileProvider`, but this functionality will be added to future `PosixFileProvider` class.
+To upload a file:

-### Monitoring FIle Changes
+```swift
+let fileURL = FileManager.default.urls(for: .documentDirectory, in: .userDomainMask).first!.appendingPathComponent("image.jpg")
+documentsProvider.copyItem(localFile: fileURL, to: "/upload/image.jpg", overwrite: true, completionHandler: nil)
+```
+
+To download a file:
+
+```swift
+let fileURL = FileManager.default.urls(for: .documentDirectory, in: .userDomainMask).first!.appendingPathComponent("image.jpg")
+documentsProvider.copyItem(path: "/download/image.jpg", toLocalURL: fileURL, overwrite: true, completionHandler: nil)
+```
+
+* It's safe only to assume these methods **won't** handle directories to upload/download recursively. If you need, you can list directories, create directories on target and copy files using these methods.
+* FTP provider allows developer to either use apple implemented `URLSessionDownloadTask` or custom implemented method based on stream task via `useAppleImplementation` property. FTP protocol is not supported by background session.
+
+### Operation Progress
+
+Creating/Copying/Deleting/Searching functions return a `(NS)Progress`. It provides operation type, progress and a `.cancel()` method which allows you to cancel operation in midst. You can check `cancellable` property to check either you can cancel operation via this object or not.
+
+- **Note:** Progress reporting is not supported by native `(NS)FileManager` so `LocalFileProvider`.
+
+### Undo Operations
+
+Providers conform to `FileProviderUndoable` can perform undo for **some** operations like moving/renaming, copying and creating (file or folder). **Now, only `LocalFileProvider` supports this feature.** To implement:
+
+```swift
+// To setup a new UndoManager:
+documentsProvider.setupUndoManager()
+// or if you have an UndoManager object already:
+documentsProvider.undoManager = self.undoManager
+
+// e.g.: To undo last operation manually:
+documentsProvider.undoManager?.undo()
+``` 
+
+You can also bind `UndoManager` object with view controller to use shake gesture and builtin undo support in iOS/macOS, add these code to your ViewController class like this sample code:
+
+```swift
+class ViewController: UIViewController
+    override var canBecomeFirstResponder: Bool {
+        return true
+    }
+    
+    override var undoManager: UndoManager? {
+        return (provider as? FileProvideUndoable)?.undoManager
+    }
+    
+    override func viewDidAppear(_ animated: Bool) {
+        super.viewDidAppear(animated)
+        // Your code here
+        UIApplication.shared.applicationSupportsShakeToEdit = true
+        self.becomeFirstResponder()
+    }
+    
+    override func viewWillDisappear(_ animated: Bool) {
+        super.viewWillDisappear(animated)
+        // Your code here
+        UIApplication.shared.applicationSupportsShakeToEdit = false
+        self.resignFirstResponder()
+    }
+    // The rest of your implementation
+}
+```
+
+### File Coordination
+
+`LocalFileProvider` and its descendents has a `isCoordinating` property. By setting this, provider will use `NSFileCoordinating` class to do all file operations. It's mandatory for iCloud, while recommended when using shared container or anywhere that simultaneous operations on a file/folder is common.
+
+### Monitoring File Changes

 You can monitor updates in some file system (Local and SMB2), there is three methods in supporting provider you can use to register a handler, to unregister and to check whether it's being monitored or not. It's useful to find out when new files added or removed from directory and update user interface. The handler will be dispatched to main threads to avoid UI bugs with a 0.25 sec delay.

-	documentsProvider.registerNotifcation(path: provider.currentPath)
-	{
-		// calling functions to update UI 
-	}
+```swift
+// to register a new notification handler
+documentsProvider.registerNotifcation(path: provider.currentPath) {
+	// calling functions to update UI 
+}
 	
-	// To discontinue monitoring folders:
-	documentsProvider.unregisterNotifcation(path: provider.currentPath)
+// To discontinue monitoring folders:
+documentsProvider.unregisterNotifcation(path: provider.currentPath)
+```

 * **Please note** in LocalFileProvider it will also monitor changes in subfolders. This behaviour can varies according to file system specification.

+### Thumbnail and meta-information
+
+Providers which conform `ExtendedFileProvider` are able to generate thumbnail or provide file meta-information for images, media and pdf files.
+
+Local, OneDrive and Dropbox providers support this functionality.
+
+##### Thumbnails
+To check either file thumbnail is supported or not and fetch thumbnail, use (and modify) these example code:
+
+```swift
+let path = "/newImage.jpg"
+let thumbSize = CGSize(width: 64, height: 64) // or nil which renders to default dimension of provider
+if documentsProvider.thumbnailOfFileSupported(path: path {
+    documentsProvider.thumbnailOfFile(path: file.path, dimension: thumbSize, completionHandler: { (image, error) in
+        // Interacting with UI must be placed in main thread
+        DispatchQueue.main.async {
+            self.previewImage.image = image
+        }
+    }
+}
+```
+
+* Please note it won't cache generated images. if you don't do it yourself, it may hit you app's performance.
+
+##### Meta-informations
+
+To get meta-information like image/video taken date, location, dimension, etc., use (and modify) these example code:
+
+```swift
+if documentsProvider..propertiesOfFile(path: file.path, completionHandler: { (propertiesDictionary, keys, error) in
+    for key in keys {
+        print("\(key): \(propertiesDictionary[key])")
+    }
+}
+```
+
+* **Bonus:** You can modify/extend Local provider generator by setting `LocalFileInformationGenerator` static variables and methods
+
 ## Contribute

 We would love for you to contribute to **FileProvider**, check the `LICENSE` file for more info.

+Things you may consider to help us:
+
+- [ ] Implement request/response stack for `SMBClient`
+- [ ] Implement Test-case (`XCTest`)
+- [ ] Add Sample project for iOS
+- [ ] Add Sample project for macOS
+
 ## Projects in use

 * [EDM - Browse and Receive Files](https://itunes.apple.com/us/app/edm-browse-and-receive-files/id948397575?ls=1&mt=8)
@@ -286,17 +483,31 @@ If you used this library in your project, you can open an issue to inform us.

 ## Meta

-Amir-Abbas Mousavian  – [@amosavian](https://twitter.com/amosavian)
+Amir-Abbas Mousavian – [@amosavian](https://twitter.com/amosavian)
+
+Thanks to [Hootan Moradi](https://github.com/hoootan) for designing logo.

 Distributed under the MIT license. See `LICENSE` for more information.

 [https://github.com/amosavian/](https://github.com/amosavian/)

-[swift-image]:https://img.shields.io/badge/swift-3.0-orange.svg
+[cocoapods]: https://cocoapods.org/pods/FilesProvider
+[cocoapods-old]: https://cocoapods.org/pods/FileProvider
+[swift-image]: https://img.shields.io/badge/swift-3.0,%203.1-orange.svg
 [swift-url]: https://swift.org/
-[license-image]: https://img.shields.io/badge/License-MIT-blue.svg
+[platform-image]: https://img.shields.io/cocoapods/p/FilesProvider.svg
+[license-image]: https://img.shields.io/github/license/amosavian/FileProvider.svg
 [license-url]: LICENSE
 [codebeat-image]: https://codebeat.co/badges/7b359f48-78eb-4647-ab22-56262a827517
 [codebeat-url]: https://codebeat.co/projects/github-com-amosavian-fileprovider
 [travis-image]: https://img.shields.io/travis/amosavian/FileProvider/master.svg
-[travis-url]: https://travis-ci.org/amosavian/FileProvider
+[travis-url]: https://travis-ci.org/amosavian/FileProvider
+[release-url]: https://github.com/amosavian/FileProvider/releases
+[release-image]: https://img.shields.io/github/release/amosavian/FileProvider.svg
+[carthage-image]: https://img.shields.io/badge/Carthage-compatible-4BC51D.svg
+[cocoapods-downloads-old]: https://img.shields.io/cocoapods/dt/FileProvider.svg
+[cocoapods-apps-old]: https://img.shields.io/cocoapods/at/FileProvider.svg
+[cocoapods-downloads]: https://img.shields.io/cocoapods/dt/FilesProvider.svg
+[cocoapods-apps]: https://img.shields.io/cocoapods/at/FilesProvider.svg
+[docs-image]: https://img.shields.io/cocoapods/metrics/doc-percent/FilesProvider.svg
+[docs-url]: http://cocoadocs.org/docsets/FilesProvider/
@@ -1,29 +0,0 @@
-//
-// AEXML.h
-//
-// Copyright (c) 2014 Marko Tadić <tadija@me.com> http://tadija.net
-//
-// Permission is hereby granted, free of charge, to any person obtaining a copy
-// of this software and associated documentation files (the "Software"), to deal
-// in the Software without restriction, including without limitation the rights
-// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
-// copies of the Software, and to permit persons to whom the Software is
-// furnished to do so, subject to the following conditions:
-//
-// The above copyright notice and this permission notice shall be included in all
-// copies or substantial portions of the Software.
-//
-// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
-// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
-// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
-// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
-// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
-// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
-// SOFTWARE.
-//
-
-#import <Foundation/Foundation.h>
-
-FOUNDATION_EXPORT double AEXMLVersionNumber;
-FOUNDATION_EXPORT const unsigned char AEXMLVersionString[];
-
@@ -29,7 +29,7 @@ import Foundation

    XML Parsing is also done with this object.
 */
-open class AEXMLDocument: AEXMLElement {
+internal class AEXMLDocument: AEXMLElement {
    
    // MARK: - Properties
    
@@ -30,7 +30,7 @@ import Foundation
    You can access its structure by using subscript like this: `element["foo"]["bar"]` which would
    return `<bar></bar>` element from `<element><foo><bar></bar></foo></element>` XML as an `AEXMLElement` object.
 */
-open class AEXMLElement {
+internal class AEXMLElement {
    
    // MARK: - Properties
    
@@ -86,7 +86,7 @@ open class AEXMLElement {
    /// The first element with given name **(Empty element with error if not exists)**.
    open subscript(key: String) -> AEXMLElement {
        guard let
-            first = children.filter({ $0.name == key }).first
+            first = children.first(where: { $0.name == key })
        else {
            let errorElement = AEXMLElement(name: key)
            errorElement.error = AEXMLError.elementNotFound
@@ -25,7 +25,7 @@
 import Foundation

 /// A type representing error value that can be thrown or inside `error` property of `AEXMLElement`.
-public enum AEXMLError: Error {
+internal enum AEXMLError: Error {
    /// This will be inside `error` property of `AEXMLElement` when subscript is used for not-existing element.
    case elementNotFound
    
@@ -1,26 +0,0 @@
-<?xml version="1.0" encoding="UTF-8"?>
-<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
-<plist version="1.0">
-<dict>
-	<key>CFBundleDevelopmentRegion</key>
-	<string>en</string>
-	<key>CFBundleExecutable</key>
-	<string>$(EXECUTABLE_NAME)</string>
-	<key>CFBundleIdentifier</key>
-	<string>$(PRODUCT_BUNDLE_IDENTIFIER)</string>
-	<key>CFBundleInfoDictionaryVersion</key>
-	<string>6.0</string>
-	<key>CFBundleName</key>
-	<string>$(PRODUCT_NAME)</string>
-	<key>CFBundlePackageType</key>
-	<string>FMWK</string>
-	<key>CFBundleShortVersionString</key>
-	<string>3.0.0</string>
-	<key>CFBundleSignature</key>
-	<string>????</string>
-	<key>CFBundleVersion</key>
-	<string>$(CURRENT_PROJECT_VERSION)</string>
-	<key>NSPrincipalClass</key>
-	<string></string>
-</dict>
-</plist>
@@ -0,0 +1,19 @@
+Copyright (c) 2014-2017 Marko Tadić <tadija@me.com> http://tadija.net
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.
@@ -9,7 +9,7 @@
 import Foundation

 /// Options used in `AEXMLDocument`
-public struct AEXMLOptions {
+internal struct AEXMLOptions {
    
    /// Values used in XML Document header
    public struct DocumentHeader {
@@ -0,0 +1,854 @@
+//
+//  CloudFileProvider.swift
+//  FileProvider
+//
+//  Created by Amir Abbas Mousavian.
+//  Copyright © 2017 Mousavian. Distributed under MIT license.
+//
+
+import Foundation
+
+/**
+ Allows accessing to iCloud Drive stored files. Determine scope when initializing, to either access
+ to public documents folder or files stored as data.
+ 
+ To setup a functional iCloud container, please
+ [read this page](https://medium.com/ios-os-x-development/icloud-drive-documents-1a46b5706fe1).
+ */
+open class CloudFileProvider: LocalFileProvider, FileProviderSharing {
+    /// An string to identify type of provider.
+    open override class var type: String { return "iCloudDrive" }
+    
+    /// Forces file operations to use `NSFileCoordinating`,
+    /// Actually this is readonly, and value is always true.
+    override open var isCoorinating: Bool {
+        get {
+            return true
+        }
+        set {
+            assert(true, "CloudFileProvider.isCoorinating can't be set")
+            return
+        }
+    }
+    
+    /// The fully-qualified container identifier for an iCloud container directory.
+    open fileprivate(set) var containerId: String?
+    
+    /// Scope of container, indicates user can manipulate data/files or not.
+    open fileprivate(set) var scope: UbiquitousScope
+    
+    /// Set this property to ignore initiations asserting to be on secondary thread
+    static open var asserting: Bool = true
+    
+    /**
+     Initializes the provider for the iCloud container associated with the specified identifier and 
+     establishes access to that container.
+     
+     - Important: Do not call this method from your app’s main thread. Because this method might take a nontrivial amount of time to set up iCloud and return the requested URL, you should always call it from a secondary thread.
+     
+     - Parameter containerId: The fully-qualified container identifier for an iCloud container directory. The string you specify must not contain wildcards and must be of the form `<TEAMID>.<CONTAINER>`, where `<TEAMID>` is your development team ID and `<CONTAINER>` is the bundle identifier of the container you want to access.\
+         The container identifiers for your app must be declared in the `com.apple.developer.ubiquity-container-identifiers` array of the `.entitlements` property list file in your Xcode project.\
+         If you specify nil for this parameter, this method uses the first container listed in the `com.apple.developer.ubiquity-container-identifiers` entitlement array.
+     - Parameter scope: Use `.documents` (default) to put documents that the user is allowed to access inside a Documents subdirectory. Otherwise use `.data` to store user-related data files that your app needs to share but that are not files you want the user to manipulate directly.
+    */
+    public init? (containerId: String?, scope: UbiquitousScope = .documents) {
+        assert(!(CloudFileProvider.asserting && Thread.isMainThread), "CloudFileProvider.init(containerId:) is not recommended to be executed on Main Thread.")
+        guard FileManager.default.ubiquityIdentityToken != nil else {
+            return nil
+        }
+        guard let ubiquityURL = FileManager.default.url(forUbiquityContainerIdentifier: containerId) else {
+            return nil
+        }
+        self.containerId = containerId
+        self.scope = scope
+        let baseURL: URL
+        if scope == .documents {
+            baseURL = ubiquityURL.appendingPathComponent("Documents/")
+        } else {
+            baseURL = ubiquityURL
+        }
+        
+        super.init(baseURL: baseURL)
+        self.isCoorinating = true
+        
+        #if swift(>=3.1)
+        let queueLabel = "FileProvider.\(Swift.type(of: self).type)"
+        #else
+        let queueLabel = "FileProvider.\(type(of: self).type)"
+        #endif
+        dispatch_queue = DispatchQueue(label: queueLabel, attributes: .concurrent)
+        operation_queue = OperationQueue()
+        operation_queue.name = "\(queueLabel).Operation"
+        
+        fileManager.url(forUbiquityContainerIdentifier: containerId)
+        opFileManager.url(forUbiquityContainerIdentifier: containerId)
+        
+        try? fileManager.createDirectory(at: baseURL, withIntermediateDirectories: true)
+    }
+    
+    
+    public required convenience init?(coder aDecoder: NSCoder) {
+        guard let containerId = aDecoder.decodeObject(forKey: "containerId") as? String,
+            let scopeString = aDecoder.decodeObject(forKey: "scope") as? String,
+            let scope = UbiquitousScope(rawValue: scopeString) else {
+            return nil
+        }
+        self.init(containerId: containerId, scope: scope)
+        self.currentPath   = aDecoder.decodeObject(forKey: "currentPath") as? String ?? ""
+        self.isCoorinating = aDecoder.decodeBool(forKey: "isCoorinating")
+    }
+    
+    open override func encode(with aCoder: NSCoder) {
+        aCoder.encode(self.containerId, forKey: "containerId")
+        aCoder.encode(self.scope.rawValue, forKey: "scope")
+        aCoder.encode(self.currentPath, forKey: "currentPath")
+        aCoder.encode(self.isCoorinating, forKey: "isCoorinating")
+    }
+    
+    open override func copy(with zone: NSZone? = nil) -> Any {
+        let copy = CloudFileProvider(containerId: self.containerId, scope: self.scope)
+        copy?.currentPath = self.currentPath
+        copy?.delegate = self.delegate
+        copy?.fileOperationDelegate = self.fileOperationDelegate
+        return copy as Any
+    }
+    
+    /**
+     Returns an Array of `FileObject`s identifying the the directory entries via asynchronous completion handler.
+     
+     If the directory contains no entries or an error is occured, this method will return the empty array.
+     
+     - Parameter path: path to target directory. If empty, `currentPath` value will be used.
+     - Parameter completionHandler: a closure with result of directory entries or error.
+         `contents`: An array of `FileObject` identifying the the directory entries.
+         `error`: Error returned by system.
+     */
+    open override func contentsOfDirectory(path: String, completionHandler: @escaping ((_ contents: [FileObject], _ error: Error?) -> Void)) {
+        // FIXME: create runloop for dispatch_queue, start query on it
+        dispatch_queue.async {
+            let pathURL = self.url(of: path)
+            
+            let query = NSMetadataQuery()
+            query.predicate = NSPredicate(format: "%K BEGINSWITH %@", NSMetadataItemPathKey, pathURL.path)
+            query.valueListAttributes = [NSMetadataItemURLKey, NSMetadataItemFSNameKey, NSMetadataItemPathKey, NSMetadataItemFSSizeKey, NSMetadataItemContentTypeTreeKey, NSMetadataItemFSCreationDateKey, NSMetadataItemFSContentChangeDateKey]
+            query.searchScopes = [self.scope.rawValue]
+            var finishObserver: NSObjectProtocol?
+            finishObserver = NotificationCenter.default.addObserver(forName: .NSMetadataQueryDidFinishGathering, object: query, queue: nil, using: { (notification) in
+                defer {
+                    query.stop()
+                    NotificationCenter.default.removeObserver(finishObserver!)
+                }
+                
+                guard let results = query.results as? [NSMetadataItem] else {
+                    return
+                }
+                
+                query.disableUpdates()
+                
+                var contents = [FileObject]()
+                for result in results {
+                    guard let attribs = result.values(forAttributes: [NSMetadataItemURLKey, NSMetadataItemFSNameKey, NSMetadataItemPathKey, NSMetadataItemFSSizeKey, NSMetadataItemContentTypeTreeKey, NSMetadataItemFSCreationDateKey, NSMetadataItemFSContentChangeDateKey]) else {
+                        continue
+                    }
+                    
+                    guard let url = (attribs[NSMetadataItemURLKey] as? URL)?.standardized, url.deletingLastPathComponent().path.trimmingCharacters(in: pathTrimSet) == pathURL.path.trimmingCharacters(in: pathTrimSet) else {
+                        continue
+                    }
+                    
+                    if let file = self.mapFileObject(attributes: attribs) {
+                        contents.append(file)
+                    }
+                }
+                
+                query.stop()
+                self.dispatch_queue.async {
+                    completionHandler(contents, nil)
+                }
+                
+            })
+            DispatchQueue.main.async {
+                if !query.start() {
+                    self.dispatch_queue.async {
+                        completionHandler([], self.throwError(path, code: CocoaError.fileReadNoPermission))
+                    }
+                }
+            }
+        }
+    }
+    
+    /// Please don't rely this function to get iCloud drive total and remaining capacity
+    /// - Important: iCloud Storage size and free space is unavailable, it returns local space
+    open override func storageProperties(completionHandler: (@escaping (_ total: Int64, _ used: Int64) -> Void)) {
+        super.storageProperties(completionHandler: completionHandler)
+    }
+    
+    /**
+     Returns a `FileObject` containing the attributes of the item (file, directory, symlink, etc.) at the path in question via asynchronous completion handler.
+     
+     If the directory contains no entries or an error is occured, this method will return the empty `FileObject`.
+     
+     - Parameter path: path to target directory. If empty, `currentPath` value will be used.
+     - Parameter completionHandler: a closure with result of directory entries or error.
+         `attributes`: A `FileObject` containing the attributes of the item.
+         `error`: Error returned by system.
+     */
+    open override func attributesOfItem(path: String, completionHandler: @escaping ((_ attributes: FileObject?, _ error: Error?) -> Void)) {
+        dispatch_queue.async {
+            let pathURL = self.url(of: path)
+            let query = NSMetadataQuery()
+            query.predicate = NSPredicate(format: "%K LIKE %@", NSMetadataItemPathKey, pathURL.path)
+            query.valueListAttributes = [NSMetadataItemURLKey, NSMetadataItemFSNameKey, NSMetadataItemPathKey, NSMetadataItemFSSizeKey, NSMetadataItemContentTypeTreeKey, NSMetadataItemFSCreationDateKey, NSMetadataItemFSContentChangeDateKey]
+            query.searchScopes = [self.scope.rawValue]
+            var finishObserver: NSObjectProtocol?
+            finishObserver = NotificationCenter.default.addObserver(forName: .NSMetadataQueryDidFinishGathering, object: query, queue: nil, using: { (notification) in
+                defer {
+                    query.stop()
+                    NotificationCenter.default.removeObserver(finishObserver!)
+                }
+                
+                query.disableUpdates()
+                
+                guard let result = (query.results as? [NSMetadataItem])?.first, let attribs = result.values(forAttributes: [NSMetadataItemURLKey, NSMetadataItemFSNameKey, NSMetadataItemPathKey, NSMetadataItemFSSizeKey, NSMetadataItemContentTypeTreeKey, NSMetadataItemFSCreationDateKey, NSMetadataItemFSContentChangeDateKey]) else {
+                    let error = self.throwError(path, code: CocoaError.fileNoSuchFile)
+                    self.dispatch_queue.async {
+                        completionHandler(nil, error)
+                    }
+                    return
+                }
+                
+                if let file = self.mapFileObject(attributes: attribs) {
+                    self.dispatch_queue.async {
+                        completionHandler(file, nil)
+                    }
+                } else {
+                    let noFileError = self.throwError(path, code: CocoaError.fileNoSuchFile)
+                    self.dispatch_queue.async {
+                        completionHandler(nil, noFileError)
+                    }
+                }
+            })
+            DispatchQueue.main.async {
+                if !query.start() {
+                    self.dispatch_queue.async {
+                        completionHandler(nil, self.throwError(path, code: CocoaError.fileReadNoPermission))
+                    }
+                }
+            }
+        }
+    }
+    
+    /**
+     Search files inside directory using query asynchronously.
+     
+     - Note: For now only it's limited to file names. `query` parameter may take `NSPredicate` format in near future.
+     
+     - Parameters:
+         - path: location of directory to start search
+         - recursive: Searching subdirectories of path
+         - query: Simple string of file name to be search (for now).
+         - foundItemHandler: Closure which is called when a file is found
+         - completionHandler: Closure which will be called after finishing search. Returns an arry of `FileObject` or error if occured.
+     */
+    open override func searchFiles(path: String, recursive: Bool, query: NSPredicate, foundItemHandler: ((FileObject) -> Void)?, completionHandler: @escaping ((_ files: [FileObject], _ error: Error?) -> Void)) -> Progress? {
+        
+        let mapDict: [String: String] = ["url": NSMetadataItemURLKey, "name": NSMetadataItemFSNameKey, "path": NSMetadataItemPathKey, "filesize": NSMetadataItemFSSizeKey, "modifiedDate": NSMetadataItemFSContentChangeDateKey, "creationDate": NSMetadataItemFSCreationDateKey, "contentType": NSMetadataItemContentTypeKey]
+        
+        func updateQueryKeys(_ queryComponent: NSPredicate) -> NSPredicate {
+            if let cQuery = queryComponent as? NSCompoundPredicate {
+                let newSub = cQuery.subpredicates.map { updateQueryKeys($0 as! NSPredicate) }
+                switch cQuery.compoundPredicateType {
+                case .and: return NSCompoundPredicate(andPredicateWithSubpredicates: newSub)
+                case .not: return NSCompoundPredicate(notPredicateWithSubpredicate: newSub.first!)
+                case .or:  return NSCompoundPredicate(orPredicateWithSubpredicates: newSub)
+                }
+            } else if let cQuery = queryComponent as? NSComparisonPredicate {
+                var newLeft = cQuery.leftExpression
+                var newRight = cQuery.rightExpression
+                if newLeft.expressionType == .keyPath, let newKey = mapDict[newLeft.keyPath] {
+                    newLeft = NSExpression(forKeyPath: newKey)
+                }
+                if newRight.expressionType == .keyPath, let newKey = mapDict[newRight.keyPath] {
+                    newRight = NSExpression(forKeyPath: newKey)
+                }
+                if newLeft.expressionType == .keyPath, newLeft.keyPath == "type" {
+                    newRight = NSExpression(forConstantValue: newRight.constantValue as? String == "directory" ? "public.directory": "public.data")
+                }
+                if newRight.expressionType == .keyPath, newRight.keyPath == "type" {
+                    newLeft = NSExpression(forConstantValue: newLeft.constantValue as? String == "directory" ? "public.directory": "public.data")
+                }
+                return NSComparisonPredicate(leftExpression: newLeft, rightExpression: newRight, modifier: cQuery.comparisonPredicateModifier, type: cQuery.predicateOperatorType, options: cQuery.options)
+            } else {
+                return queryComponent
+            }
+        }
+        
+        let progress = Progress(parent: nil, userInfo: nil)
+        
+        dispatch_queue.async {
+            let pathURL = self.url(of: path)
+            progress.setUserInfoObject(pathURL, forKey: .fileURLKey)
+            let mdquery = NSMetadataQuery()
+            mdquery.predicate = NSPredicate(format: "(%K BEGINSWITH %@) && (\(updateQueryKeys(query).predicateFormat))", NSMetadataItemPathKey, pathURL.path)
+            mdquery.searchScopes = [self.scope.rawValue]
+            
+            var lastReportedCount = 0
+            
+            progress.cancellationHandler = { [weak mdquery] in
+                mdquery?.stop()
+            }
+            
+            if let foundItemHandler = foundItemHandler {
+                var updateObserver: NSObjectProtocol?
+                
+                // FIXME: Remove this section as it won't work as expected on iCloud
+                updateObserver = NotificationCenter.default.addObserver(forName: .NSMetadataQueryGatheringProgress, object: mdquery, queue: nil, using: { (notification) in
+                    
+                    mdquery.disableUpdates()
+                    
+                    guard mdquery.resultCount > lastReportedCount else { return }
+                    
+                    for index in lastReportedCount..<mdquery.resultCount {
+                        guard let attribs = (mdquery.result(at: index) as? NSMetadataItem)?.values(forAttributes: [NSMetadataItemURLKey, NSMetadataItemFSNameKey, NSMetadataItemPathKey, NSMetadataItemFSSizeKey, NSMetadataItemContentTypeTreeKey, NSMetadataItemFSCreationDateKey, NSMetadataItemFSContentChangeDateKey]) else {
+                            continue
+                        }
+                        
+                        guard let url = (attribs[NSMetadataItemURLKey] as? URL)?.standardized, recursive || url.deletingLastPathComponent().path.trimmingCharacters(in: pathTrimSet) == pathURL.path.trimmingCharacters(in: pathTrimSet) else {
+                            continue
+                        }
+                        
+                        if let file = self.mapFileObject(attributes: attribs) {
+                            foundItemHandler(file)
+                        }
+                    }
+                    lastReportedCount = mdquery.resultCount
+                    progress.totalUnitCount = Int64(lastReportedCount)
+                    
+                    mdquery.enableUpdates()
+                })
+            }
+            
+            var finishObserver: NSObjectProtocol?
+            finishObserver = NotificationCenter.default.addObserver(forName: .NSMetadataQueryDidFinishGathering, object: mdquery, queue: nil, using: { (notification) in
+                defer {
+                    mdquery.stop()
+                    NotificationCenter.default.removeObserver(finishObserver!)
+                }
+                
+                guard let results = mdquery.results as? [NSMetadataItem] else {
+                    return
+                }
+                
+                mdquery.disableUpdates()
+                
+                var contents = [FileObject]()
+                for result in results {
+                    guard let attribs = result.values(forAttributes: [NSMetadataItemURLKey, NSMetadataItemFSNameKey, NSMetadataItemPathKey, NSMetadataItemFSSizeKey, NSMetadataItemContentTypeTreeKey, NSMetadataItemFSCreationDateKey, NSMetadataItemFSContentChangeDateKey]) else {
+                        continue
+                    }
+                    
+                    guard let url = (attribs[NSMetadataItemURLKey] as? URL)?.standardized, recursive || url.deletingLastPathComponent().path.trimmingCharacters(in: pathTrimSet) == pathURL.path.trimmingCharacters(in: pathTrimSet) else {
+                        continue
+                    }
+                    
+                    if let file = self.mapFileObject(attributes: attribs) {
+                        contents.append(file)
+                    }
+                }
+                progress.completedUnitCount = Int64(contents.count)
+                self.dispatch_queue.async {
+                    completionHandler(contents, nil)
+                }
+            })
+            
+            DispatchQueue.main.async {
+                progress.setUserInfoObject(Date(), forKey: .startingTimeKey)
+                if !mdquery.start() {
+                    self.dispatch_queue.async {
+                        completionHandler([], self.throwError(path, code: CocoaError.fileReadNoPermission))
+                    }
+                }
+            }
+        }
+        
+        return progress
+    }
+    
+    open override func isReachable(completionHandler: @escaping (Bool) -> Void) {
+        dispatch_queue.async {
+            completionHandler(self.fileManager.ubiquityIdentityToken != nil)
+        }
+    }
+    
+    /**
+     Creates a new directory at the specified path asynchronously.
+     This will create any necessary intermediate directories.
+     
+     - Parameters:
+       - folder: Directory name.
+       - at: Parent path of new directory.
+       - completionHandler: If an error parameter was provided, a presentable `Error` will be returned.
+     - Returns: A `Progress` object to get progress or cancel progress. Doesn't work on `CloudFileProvider`.
+     */
+    @discardableResult
+    open override func create(folder folderName: String, at atPath: String, completionHandler: SimpleCompletionHandler) -> Progress? {
+        return super.create(folder: folderName, at: atPath, completionHandler: completionHandler)
+    }
+    
+    /**
+     Moves a file or directory from `path` to designated path asynchronously.
+     When you want move a file, destination path should also consists of file name.
+     Either a new name or the old one.
+     
+     - Parameters:
+       - path: original file or directory path.
+       - to: destination path of file or directory, including file/directory name.
+       - overwrite: Destination file should be overwritten if file is already exists. **Default** is `false`.
+       - completionHandler: If an error parameter was provided, a presentable `Error` will be returned.
+     - Returns: A `Progress` object to get progress or cancel progress. Doesn't work on `CloudFileProvider`.
+     */
+    @discardableResult
+    open override func moveItem(path: String, to toPath: String, overwrite: Bool = false, completionHandler: SimpleCompletionHandler) -> Progress? {
+        return super.moveItem(path: path, to: toPath, overwrite: overwrite, completionHandler: completionHandler)
+    }
+    
+    /**
+     Copies a file or directory from `path` to designated path asynchronously.
+     When want copy a file, destination path should also consists of file name.
+     Either a new name or the old one.
+     
+     - Parameters:
+       - path: original file or directory path.
+       - to: destination path of file or directory, including file/directory name.
+       - overwrite: Destination file should be overwritten if file is already exists. **Default** is `false`.
+       - completionHandler: If an error parameter was provided, a presentable `Error` will be returned.
+     - Returns: A `Progress` object to get progress or cancel progress. Doesn't work on `CloudFileProvider`.
+     */
+    @discardableResult
+    open override func copyItem(path: String, to toPath: String, overwrite: Bool = false, completionHandler: SimpleCompletionHandler) -> Progress? {
+        return super.copyItem(path: path, to: toPath, overwrite: overwrite, completionHandler: completionHandler)
+    }
+    
+    /**
+     Removes the file or directory at the specified path.
+     
+     - Important: Due to a bug (race condition?) in Apple API, it takes about 3-5 seconds to update containing folder
+       list and triggering notification registered for directory while completion handler will run almost immediately.
+       It's your responsibility to workaourd this bug/feature and mark file as deleted in your software.
+     
+     - Parameters:
+       - path: file or directory path.
+       - completionHandler: If an error parameter was provided, a presentable `Error` will be returned.
+     - Returns: A `Progress` object to get progress or cancel progress. Doesn't work on `CloudFileProvider`.
+     */
+    @discardableResult
+    open override func removeItem(path: String, completionHandler: SimpleCompletionHandler) -> Progress? {
+        return super.removeItem(path: path, completionHandler: completionHandler)
+    }
+    
+    /**
+     Uploads a file from local file url to designated path asynchronously.
+     Method will fail if source is not a local url with `file://` scheme.
+     
+     - Parameters:
+       - localFile: a file url to file.
+       - to: destination path of file, including file/directory name.
+       - overwrite: Destination file should be overwritten if file is already exists. **Default** is `false`.
+       - completionHandler: If an error parameter was provided, a presentable `Error` will be returned.
+     - Returns: A `Progress` object to get progress or cancel progress.
+     */
+    @discardableResult
+    open override func copyItem(localFile: URL, to toPath: String, overwrite: Bool, completionHandler: SimpleCompletionHandler) -> Progress? {
+        // TODO: Make use of overwrite parameter
+        let opType = FileOperationType.copy(source: localFile.absoluteString, destination: toPath)
+        let progress = Progress(parent: nil, userInfo: nil)
+        progress.setUserInfoObject(opType, forKey: .fileProvderOperationTypeKey)
+        progress.kind = .file
+        progress.isCancellable = false
+        progress.setUserInfoObject(localFile, forKey: .fileURLKey)
+        progress.setUserInfoObject(Progress.FileOperationKind.downloading, forKey: .fileOperationKindKey)
+        monitorFile(path: toPath, opType: opType, progress: progress)
+        operation_queue.addOperation {
+            let tempFolder: URL
+            if #available(iOS 10.0, macOS 10.12, tvOS 10.0, *) {
+                tempFolder = FileManager.default.temporaryDirectory
+            } else {
+                tempFolder = URL(fileURLWithPath: NSTemporaryDirectory())
+            }
+            let tmpFile = tempFolder.appendingPathComponent(UUID().uuidString)
+            
+            do {
+                try self.opFileManager.copyItem(at: localFile, to: tmpFile)
+                let toUrl = self.url(of: toPath)
+                try self.opFileManager.setUbiquitous(true, itemAt: tmpFile, destinationURL: toUrl)
+                completionHandler?(nil)
+                DispatchQueue.main.async(execute: {
+                    self.delegate?.fileproviderSucceed(self, operation: opType)
+                })
+            } catch let e {
+                if self.opFileManager.fileExists(atPath: tmpFile.path) {
+                    try? self.opFileManager.removeItem(at: tmpFile)
+                }
+                completionHandler?(e)
+                DispatchQueue.main.async(execute: {
+                    self.delegate?.fileproviderFailed(self, operation: opType)
+                })
+            }
+        }
+        return progress
+    }
+    
+    /**
+     Download a file from `path` to designated local file url asynchronously.
+     Method will fail if destination is not a local url with `file://` scheme.
+     
+     - Parameters:
+       - path: original file or directory path.
+       - toLocalURL: destination local url of file, including file/directory name.
+       - completionHandler: If an error parameter was provided, a presentable `Error` will be returned.
+     - Returns: A `Progress` object to get progress or cancel progress.
+     */
+    @discardableResult
+    open override func copyItem(path: String, toLocalURL: URL, completionHandler: SimpleCompletionHandler) -> Progress? {
+        let opType = FileOperationType.copy(source: path, destination: toLocalURL.absoluteString)
+        let progress = Progress(parent: nil, userInfo: nil)
+        progress.setUserInfoObject(opType, forKey: .fileProvderOperationTypeKey)
+        progress.kind = .file
+        progress.isCancellable = false
+        progress.setUserInfoObject(self.url(of: path), forKey: .fileURLKey)
+        progress.setUserInfoObject(Progress.FileOperationKind.downloading, forKey: .fileOperationKindKey)
+        monitorFile(path: path, opType: opType, progress: progress)
+        do {
+            try self.opFileManager.startDownloadingUbiquitousItem(at: self.url(of: path))
+        } catch let e {
+            completionHandler?(e)
+            DispatchQueue.main.async(execute: {
+                self.delegate?.fileproviderFailed(self, operation: opType)
+            })
+            return nil
+        }
+        let _ = super.copyItem(path: path, toLocalURL: toLocalURL, completionHandler: completionHandler)
+        return progress
+    }
+    
+    /**
+     Retreives a `Data` object with the contents of the file asynchronously vis contents argument of completion handler.
+     If path specifies a directory, or if some other error occurs, data will be nil.
+     
+     - Parameters:
+       - path: Path of file.
+       - completionHandler: a closure with result of file contents or error.
+         `contents`: contents of file in a `Data` object.
+         `error`: Error returned by system.
+     - Returns: A `Progress` object to get progress or cancel progress.
+     */
+    @discardableResult
+    open override func contents(path: String, completionHandler: @escaping ((_ contents: Data?, _ error: Error?) -> Void)) -> Progress? {
+        let operation = FileOperationType.fetch(path: path)
+        let progress = Progress(parent: nil, userInfo: nil)
+        progress.setUserInfoObject(operation, forKey: .fileProvderOperationTypeKey)
+        progress.kind = .file
+        progress.setUserInfoObject(self.url(of: path), forKey: .fileURLKey)
+        progress.setUserInfoObject(Progress.FileOperationKind.downloading, forKey: .fileOperationKindKey)
+        monitorFile(path: path, opType: operation, progress: progress)
+        _ = super.contents(path: path, completionHandler: completionHandler)
+        return progress
+    }
+    
+    /**
+     Retreives a `Data` object with a portion contents of the file asynchronously vis contents argument of completion handler.
+     If path specifies a directory, or if some other error occurs, data will be nil.
+     
+     - Parameters:
+       - path: Path of file.
+       - offset: First byte index which should be read. **Starts from 0.**
+       - length: Bytes count of data. Pass `-1` to read until the end of file.
+       - completionHandler: a closure with result of file contents or error.
+         `contents`: contents of file in a `Data` object.
+         `error`: Error returned by system.
+     - Returns: A `Progress` object to get progress or cancel progress.
+     */
+    @discardableResult
+    open override func contents(path: String, offset: Int64, length: Int, completionHandler: @escaping ((_ contents: Data?, _ error: Error?) -> Void)) -> Progress? {
+        let operation = FileOperationType.fetch(path: path)
+        let progress = Progress(parent: nil, userInfo: nil)
+        progress.setUserInfoObject(operation, forKey: .fileProvderOperationTypeKey)
+        progress.kind = .file
+        progress.setUserInfoObject(self.url(of: path), forKey: .fileURLKey)
+        progress.setUserInfoObject(Progress.FileOperationKind.downloading, forKey: .fileOperationKindKey)
+        monitorFile(path: path, opType: operation, progress: progress)
+        _ = super.contents(path: path, offset: offset, length: length, completionHandler: completionHandler)
+        return progress
+    }
+    
+    /**
+     Write the contents of the `Data` to a location asynchronously.
+     
+     - Parameters:
+       - path: Path of target file.
+       - contents: Data to be written into file.
+       - overwrite: Destination file should be overwritten if file is already exists. Default is `false`.
+       - atomically: data will be written to a temporary file before writing to final location. Default is `false`.
+       - completionHandler: If an error parameter was provided, a presentable `Error` will be returned.
+     - Returns: A `Progress` object to get progress or cancel progress. Doesn't work on `LocalFileProvider`.
+     */
+    @discardableResult
+    open override func writeContents(path: String, contents data: Data?, atomically: Bool, overwrite: Bool, completionHandler: SimpleCompletionHandler) -> Progress? {
+        let operation = FileOperationType.fetch(path: path)
+        let progress = Progress(parent: nil, userInfo: nil)
+        progress.setUserInfoObject(operation, forKey: .fileProvderOperationTypeKey)
+        progress.kind = .file
+        progress.setUserInfoObject(self.url(of: path), forKey: .fileURLKey)
+        progress.setUserInfoObject(Progress.FileOperationKind.downloading, forKey: .fileOperationKindKey)
+        monitorFile(path: path, opType: operation, progress: progress)
+        _ = super.writeContents(path: path, contents: data, atomically: atomically, overwrite: overwrite, completionHandler: completionHandler)
+        return progress
+    }
+    
+    fileprivate var monitors = [String: (NSMetadataQuery, NSObjectProtocol)]()
+    
+    /**
+     Starts monitoring a path and its subpaths, including files and folders, for any change,
+     including copy, move/rename, content changes, etc.
+     To avoid thread congestion, `evetHandler` will be triggered with 0.2 seconds interval,
+     and has a 0.25 second delay, to ensure it's called after updates.
+     
+     - Note: this functionality is available only in `LocalFileProvider` and `CloudFileProvider`.
+     - Note: `eventHandler` is not called on main thread, for updating UI. dispatch routine to main thread.
+     - Important: `eventHandler` may be called if file is changed in recursive subpaths of registered path.
+     This may cause negative impact on performance if a root path is being monitored.
+     
+     - Parameters:
+       - path: path of directory.
+       - eventHandler: Closure executed after change, on a secondary thread.
+     */
+    open override func registerNotifcation(path: String, eventHandler: @escaping (() -> Void)) {
+        self.unregisterNotifcation(path: path)
+        let pathURL = self.url(of: path)
+        let query = NSMetadataQuery()
+        query.predicate = NSPredicate(format: "(%K BEGINSWITH %@)", NSMetadataItemPathKey, pathURL.path)
+        query.valueListAttributes = []
+        query.searchScopes = [self.scope.rawValue]
+        
+        let updateObserver = NotificationCenter.default.addObserver(forName: .NSMetadataQueryDidUpdate, object: query, queue: nil, using: { (notification) in
+            
+            query.disableUpdates()
+            
+            eventHandler()
+            
+            query.enableUpdates()
+        })
+        
+        DispatchQueue.main.async {
+            if query.start() {
+                self.monitors[path] = (query, updateObserver)
+            }
+        }
+    }
+    
+    /// Stops monitoring the path.
+    ///
+    /// - Parameter path: path of directory.
+    open override func unregisterNotifcation(path: String) {
+        guard let (query, observer) = monitors[path] else {
+            return
+        }
+        query.disableUpdates()
+        query.stop()
+        NotificationCenter.default.removeObserver(observer)
+        monitors.removeValue(forKey: path)
+    }
+    
+    /// Investigate either the path is registered for change notification or not.
+    ///
+    /// - Parameter path: path of directory.
+    /// - Returns: Directory is being monitored or not.
+    open override func isRegisteredForNotification(path: String) -> Bool {
+        return monitors[path] != nil
+    }
+    
+    fileprivate func mapFileObject(attributes attribs: [String: Any]) -> FileObject? {
+        guard let url = (attribs[NSMetadataItemURLKey] as? URL)?.standardizedFileURL, let name = attribs[NSMetadataItemFSNameKey] as? String else {
+            return nil
+        }
+        
+        let path = self.relativePathOf(url: url)
+        let rpath = path.hasPrefix("/") ? path.substring(from: path.index(after: path.startIndex)) : path
+        let relativeUrl = URL(string: rpath.addingPercentEncoding(withAllowedCharacters: .urlPathAllowed) ?? rpath, relativeTo: self.baseURL)
+        let file = FileObject(url: relativeUrl ?? url, name: name, path: path)
+        
+        file.size = (attribs[NSMetadataItemFSSizeKey] as? NSNumber)?.int64Value ?? -1
+        file.creationDate = attribs[NSMetadataItemFSCreationDateKey] as? Date
+        file.modifiedDate = attribs[NSMetadataItemFSContentChangeDateKey] as? Date
+        let isFolder = (attribs[NSMetadataItemContentTypeTreeKey] as? [String])?.contains("public.folder") ?? false
+        let isSymbolic = (attribs[NSMetadataItemContentTypeTreeKey] as? [String])?.contains("public.symlink") ?? false
+        file.type = isFolder ? .directory : (isSymbolic ? .symbolicLink : .regular)
+        
+        return file
+    }
+    
+    fileprivate func monitorFile(path: String, opType: FileOperationType, progress: Progress?) {
+        dispatch_queue.async {
+            let pathURL = self.url(of: path)
+            let size = pathURL.fileSize
+            progress?.totalUnitCount = size > 0 ? size : 0
+            let query = NSMetadataQuery()
+            query.predicate = NSPredicate(format: "%K LIKE %@", NSMetadataItemPathKey, pathURL.path)
+            query.valueListAttributes = [NSMetadataItemURLKey, NSMetadataItemFSNameKey, NSMetadataItemPathKey, NSMetadataUbiquitousItemPercentDownloadedKey, NSMetadataUbiquitousItemPercentUploadedKey, NSMetadataItemFSSizeKey]
+            query.searchScopes = [self.scope.rawValue]
+            var updateObserver: NSObjectProtocol?
+            updateObserver = NotificationCenter.default.addObserver(forName: .NSMetadataQueryDidUpdate, object: query, queue: nil, using: { (notification) in
+                query.disableUpdates()
+                
+                guard let item = (query.results as? [NSMetadataItem])?.first else {
+                    return
+                }
+                
+                if progress?.totalUnitCount == 0, let size = item.value(forAttribute: NSMetadataItemFSSizeKey) as? Int64 {
+                    progress?.totalUnitCount = size
+                }
+                let downloaded = item.value(forAttribute: NSMetadataUbiquitousItemPercentDownloadedKey) as? Double ?? 0
+                let uploaded = item.value(forAttribute: NSMetadataUbiquitousItemPercentUploadedKey) as? Double ?? 0
+                if (downloaded == 0 || downloaded == 100) && (uploaded > 0 && uploaded < 100) {
+                    progress?.completedUnitCount = Int64(uploaded / 100 * Double(progress?.totalUnitCount ?? 0))
+                    DispatchQueue.main.async {
+                        self.delegate?.fileproviderProgress(self, operation: opType, progress: Float(uploaded / 100))
+                    }
+                } else if (uploaded == 0 || uploaded == 100) && (downloaded > 0 && downloaded < 100) {
+                    progress?.completedUnitCount = Int64(downloaded / 100 * Double(progress?.totalUnitCount ?? 0))
+                    DispatchQueue.main.async {
+                        self.delegate?.fileproviderProgress(self, operation: opType, progress: Float(downloaded / 100))
+                    }
+                } else if uploaded == 100 || downloaded == 100 {
+                    progress?.completedUnitCount = progress?.totalUnitCount ?? 0
+                    query.stop()
+                    NotificationCenter.default.removeObserver(updateObserver!)
+                    DispatchQueue.main.async {
+                        self.delegate?.fileproviderSucceed(self, operation: opType)
+                    }
+                }
+                
+                query.enableUpdates()
+            })
+            
+            DispatchQueue.main.async {
+                progress?.setUserInfoObject(Date(), forKey: .startingTimeKey)
+                query.start()
+            }
+        }
+    }
+    
+    open func publicLink(to path: String, completionHandler: @escaping ((_ link: URL?, _ attribute: FileObject?, _ expiration: Date?, _ error: Error?) -> Void)) {
+        operation_queue.addOperation {
+            do {
+                var expiration: NSDate?
+                let url = try self.opFileManager.url(forPublishingUbiquitousItemAt: self.url(of: path), expiration: &expiration)
+                self.dispatch_queue.async {
+                    completionHandler(url, nil, expiration as Date?, nil)
+                }
+            } catch let e {
+                self.dispatch_queue.async {
+                    completionHandler(nil, nil, nil, e)
+                }
+            }
+        }
+    }
+}
+
+extension CloudFileProvider {
+    
+    /// Removes local copy of file, but spares cloud copy.
+    /// - Parameter path: Path of file or directory to be removed from local
+    /// - Parameter completionHandler: If an error parameter was provided, a presentable `Error` will be returned.
+    open func evictItem(path: String, completionHandler: SimpleCompletionHandler) {
+        operation_queue.addOperation {
+            do {
+                try self.opFileManager.evictUbiquitousItem(at: self.url(of: path))
+                completionHandler?(nil)
+            } catch let e {
+                completionHandler?(e)
+            }
+        }
+    }
+    
+    /// Returns current version of file on this device and all versions of files in user devices.
+    /// - Parameter path: Path of file or directory.
+    /// - Parameter completionHandler: Retrieve current version on this device and all versions available. `currentVersion` will be nil if file doesn't exist. If an error parameter was provided, a presentable `Error` will be returned.
+    func versionsOfItem(path: String, completionHandler: @escaping ((_ currentVersion: NSFileVersion?, _ versions: [NSFileVersion], _ error: Error?) -> Void)) {
+        NotImplemented()
+    }
+    
+    /// Resolves conflicts by selecting a version.
+    /// - Parameter path: Path of file or directory.
+    /// - Parameter version: Version than will be choose as main version. `nil` value indicates current version on this device will be selected.
+    /// - Parameter completionHandler: If an error parameter was provided, a presentable `Error` will be returned.
+    func selectVersionOfItem(path: String, version: NSFileVersion? = nil, completionHandler: SimpleCompletionHandler) {
+        NotImplemented()
+    }
+}
+
+/// Scope of iCloud, wrapper for NSMetadataQueryUbiquitous...Scope constants
+public enum UbiquitousScope: RawRepresentable {
+    /// Search all files not in the Documents directories of the app’s iCloud container directories.
+    /// Use this scope to store user-related data files that your app needs to share 
+    /// but that are not files you want the user to manipulate directly.
+    case data
+    /// Search all files in the Documents directories of the app’s iCloud container directories.
+    /// Put documents that the user is allowed to access inside a Documents subdirectory.
+    case documents
+    
+    public typealias RawValue = String
+    
+    public init? (rawValue: String) {
+        switch rawValue {
+        case NSMetadataQueryUbiquitousDataScope:
+            self = .data
+        case NSMetadataQueryUbiquitousDocumentsScope:
+            self = .documents
+        default:
+            return nil
+        }
+    }
+    
+    public var rawValue: String {
+        switch self {
+        case .data:
+            return NSMetadataQueryUbiquitousDataScope
+        case .documents:
+            return NSMetadataQueryUbiquitousDocumentsScope
+        }
+    }
+}
+
+/*
+func getMetadataItem(url: URL) -> NSMetadataItem? {
+    let query = NSMetadataQuery()
+    query.predicate = NSPredicate(format: "(%K LIKE %@)", NSMetadataItemPathKey, url.path)
+    query.searchScopes = [NSMetadataQueryUbiquitousDocumentsScope, NSMetadataQueryUbiquitousDataScope]
+    
+    var item: NSMetadataItem?
+    
+    let group = DispatchGroup()
+    group.enter()
+    var finishObserver: NSObjectProtocol?
+    finishObserver = NotificationCenter.default.addObserver(forName: .NSMetadataQueryDidFinishGathering, object: query, queue: nil, using: { (notification) in
+        defer {
+            query.stop()
+            group.leave()
+            NotificationCenter.default.removeObserver(finishObserver!)
+        }
+        
+        if query.resultCount > 0 {
+            item = query.result(at: 0) as? NSMetadataItem
+        }
+        
+        query.disableUpdates()
+        
+    })
+    
+    DispatchQueue.main.async {
+        query.start()
+    }
+    _ = group.wait(timeout: .now() + 30)
+    return item
+}
+*/
@@ -10,267 +10,227 @@
 import Foundation
 import CoreGraphics

-// Because this class uses NSURLSession, it's necessary to disable App Transport Security
-// in case of using this class with unencrypted HTTP connection.
-
-open class DropboxFileProvider: NSObject,  FileProviderBasic {
-    open static let type: String = "WebDAV"
-    open let isPathRelative: Bool = true
-    open let baseURL: URL?
-    open var currentPath: String = ""
-    open var dispatch_queue: DispatchQueue {
-        willSet {
-            assert(_session == nil, "It's not effective to change dispatch_queue property after session is initialized.")
-        }
-    }
-    open weak var delegate: FileProviderDelegate?
-    open let credential: URLCredential?
+/**
+ Allows accessing to Dropbox stored files. This provider doesn't cache or save files internally, however you can
+ set `useCache` and `cache` properties to use Foundation `NSURLCache` system.
+ 
+ - Note: Uploading files and data are limited to 150MB, for now.
+ */
+open class DropboxFileProvider: HTTPFileProvider {
+    override open class var type: String { return "Dropbox" }
    
-    fileprivate var _session: URLSession?
-    fileprivate var sessionDelegate: SessionDelegate?
-    internal var session: URLSession {
-        if _session == nil {
-            self.sessionDelegate = SessionDelegate(fileProvider: self, credential: credential)
-            let queue = OperationQueue()
-            //queue.underlyingQueue = dispatch_queue
-            _session = URLSession(configuration: URLSessionConfiguration.default, delegate: sessionDelegate as URLSessionDelegate?, delegateQueue: queue)
-        }
-        return _session!
+    /// Dropbox RPC API URL, which is equal with [https://api.dropboxapi.com/2/](https://api.dropboxapi.com/2/)
+    open let apiURL: URL
+    /// Dropbox contents download/upload API URL, which is equal with [https://content.dropboxapi.com/2/](https://content.dropboxapi.com/2/)
+    open let contentURL: URL
+    
+    /**
+     Initializer for Dropbox provider with given client ID and Token.
+     These parameters must be retrieved via [OAuth2 API of Dropbox](https://www.dropbox.com/developers/reference/oauth-guide).
+     
+     There are libraries like [p2/OAuth2](https://github.com/p2/OAuth2) or [OAuthSwift](https://github.com/OAuthSwift/OAuthSwift) which can facilate the procedure to retrieve token. 
+     The latter is easier to use and prefered. Also you can use [auth0/Lock](https://github.com/auth0/Lock.iOS-OSX) which provides graphical user interface.
+     
+     - Parameter credential: a `URLCredential` object with Client ID set as `user` and Token set as `password`.
+     - Parameter cache: A URLCache to cache downloaded files and contents.
+    */
+    public init(credential: URLCredential?, cache: URLCache? = nil) {
+        self.apiURL = URL(string: "https://api.dropboxapi.com/2/")!
+        self.contentURL = URL(string: "https://content.dropboxapi.com/2/")!
+        super.init(baseURL: nil, credential: credential, cache: cache)
    }
    
-    public init? (credential: URLCredential?) {
-        self.baseURL = nil
-        dispatch_queue = DispatchQueue(label: "FileProvider.\(DropboxFileProvider.type)", attributes: DispatchQueue.Attributes.concurrent)
-        //let url = baseURL.uw_absoluteString
-        self.credential = credential
+    public required convenience init?(coder aDecoder: NSCoder) {
+        self.init(credential: aDecoder.decodeObject(forKey: "credential") as? URLCredential)
+        self.currentPath     = aDecoder.decodeObject(forKey: "currentPath") as? String ?? ""
+        self.useCache        = aDecoder.decodeBool(forKey: "useCache")
+        self.validatingCache = aDecoder.decodeBool(forKey: "validatingCache")
    }
    
-    deinit {
-        _session?.invalidateAndCancel()
+    override open func copy(with zone: NSZone? = nil) -> Any {
+        let copy = DropboxFileProvider(credential: self.credential, cache: self.cache)
+        copy.currentPath = self.currentPath
+        copy.delegate = self.delegate
+        copy.fileOperationDelegate = self.fileOperationDelegate
+        copy.useCache = self.useCache
+        copy.validatingCache = self.validatingCache
+        return copy
    }
    
-    open func contentsOfDirectory(path: String, completionHandler: @escaping ((_ contents: [FileObject], _ error: Error?) -> Void)) {
-        list(path) { (contents, cursor, error) in
+    open override func contentsOfDirectory(path: String, completionHandler: @escaping ((_ contents: [FileObject], _ error: Error?) -> Void)) {
+        let progress = Progress(parent: nil, userInfo: nil)
+        list(path, progress: progress) { (contents, cursor, error) in
            completionHandler(contents, error)
        }
    }
    
-    open func attributesOfItem(path: String, completionHandler: @escaping ((_ attributes: FileObject?, _ error: Error?) -> Void)) {
-        let url = URL(string: "https://api.dropboxapi.com/2/files/get_metadata")!
+    open override func attributesOfItem(path: String, completionHandler: @escaping ((_ attributes: FileObject?, _ error: Error?) -> Void)) {
+        let url = URL(string: "files/get_metadata", relativeTo: apiURL)!
        var request = URLRequest(url: url)
        request.httpMethod = "POST"
-        request.setValue("Bearer \(credential?.password ?? "")", forHTTPHeaderField: "Authorization")
-        request.setValue("application/json", forHTTPHeaderField: "Content-Type")
-        let requestDictionary = ["path": correctPath(path)! as NSString]
-        request.httpBody = dictionaryToJSON(requestDictionary)?.data(using: .utf8)
-        let task = session.dataTask(with: request, completionHandler: { (data, response, error) in
-            if let response = response as? HTTPURLResponse {
-                defer {
-                    self.delegateNotify(.create(path: path), error: error)
-                }
-                let code = FileProviderHTTPErrorCode(rawValue: response.statusCode)
-                let dbError: FileProviderDropboxError? = code != nil ? FileProviderDropboxError(code: code!, path: path, errorDescription: String(data: data ?? Data(), encoding: .utf8)) : nil
-                if let data = data, let jsonStr = String(data: data, encoding: .utf8), let json = jsonToDictionary(jsonStr), let file = self.mapToFileObject(json) {
-                    completionHandler(file, dbError)
-                    return
-                }
-                completionHandler(nil, dbError)
-                return
-            }
-            completionHandler(nil, error)
-        }) 
-        task.resume()
-    }
-    
-    open func storageProperties(completionHandler: @escaping ((_ total: Int64, _ used: Int64) -> Void)) {
-        let url = URL(string: "https://api.dropboxapi.com/2/users/get_space_usage")!
-        var request = URLRequest(url: url)
-        request.httpMethod = "POST"
-        request.setValue("Bearer \(credential?.password ?? "")", forHTTPHeaderField: "Authorization")
-        let task = session.dataTask(with: request, completionHandler: { (data, response, error) in
-            if let data = data, let jsonStr = String(data: data, encoding: .utf8), let json = jsonToDictionary(jsonStr) {
-                let totalSize = ((json["allocation"] as? NSDictionary)?["allocated"] as? NSNumber)?.int64Value ?? -1
-                let usedSize = (json["used"] as? NSNumber)?.int64Value ?? 0
-                completionHandler(totalSize, usedSize)
-                return
-            }
-            completionHandler(-1, 0)
-        }) 
-        task.resume()
-    }
-    
-    open weak var fileOperationDelegate: FileOperationDelegate?
-}
-
-extension DropboxFileProvider: FileProviderOperations {
-    
-    
-    public func create(folder folderName: String, at atPath: String, completionHandler: SimpleCompletionHandler) -> OperationHandle? {
-        let path = (atPath as NSString).appendingPathComponent(folderName) + "/"
-        return doOperation(.create(path: path), completionHandler: completionHandler)
-    }
-    
-    public func create(file fileAttribs: FileObject, at path: String, contents data: Data?, completionHandler: SimpleCompletionHandler) -> OperationHandle? {
-        return self.writeContents(path: path, contents: data ?? Data(), completionHandler: completionHandler)
-    }
-    
-    public func moveItem(path: String, to toPath: String, overwrite: Bool = false, completionHandler: SimpleCompletionHandler) -> OperationHandle? {
-        return doOperation(.move(source: path, destination: toPath), completionHandler: completionHandler)
-    }
-    
-    public func copyItem(path: String, to toPath: String, overwrite: Bool = false, completionHandler: SimpleCompletionHandler) -> OperationHandle? {
-        return doOperation(.copy(source: path, destination: toPath), completionHandler: completionHandler)
-    }
-    
-    public func removeItem(path: String, completionHandler: SimpleCompletionHandler) -> OperationHandle? {
-        return doOperation(.remove(path: path), completionHandler: completionHandler)
-    }
-    
-    fileprivate func doOperation(_ operation: FileOperationType, completionHandler: SimpleCompletionHandler) -> OperationHandle? {
-        guard fileOperationDelegate?.fileProvider(self, shouldDoOperation: operation) ?? true == true else {
-            return nil
-        }
-        let url: String
-        var path: String?, fromPath: String?, toPath: String?
-        switch operation {
-        case .create(path: let p):
-            url = "https://api.dropboxapi.com/2/files/create_folder"
-            path = p
-        case .copy(source: let fp, destination: let tp):
-            url = "https://api.dropboxapi.com/2/files/copy"
-            fromPath = fp
-            toPath = tp
-        case .move(source: let fp, destination: let tp):
-            url = "https://api.dropboxapi.com/2/files/move"
-            fromPath = fp
-            toPath = tp
-        case .modify(path: let p):
-            return nil
-        case .remove(path: let p):
-            url = "https://api.dropboxapi.com/2/files/delete"
-            path = p
-        case .link(link: _, target: _):
-            return nil
-        }
-        var request = URLRequest(url: URL(string: url)!)
-        request.httpMethod = "POST"
-        request.setValue("Bearer \(credential?.password ?? "")", forHTTPHeaderField: "Authorization")
-        request.setValue("application/json", forHTTPHeaderField: "Content-Type")
-        var requestDictionary = [String: AnyObject]()
-        requestDictionary["path"] = correctPath(path) as NSString?
-        requestDictionary["from_path"] = correctPath(fromPath) as NSString?
-        requestDictionary["to_path"] = correctPath(toPath) as NSString?
-        request.httpBody = dictionaryToJSON(requestDictionary)?.data(using: .utf8)
+        request.set(httpAuthentication: credential, with: .oAuth2)
+        request.set(contentType: .json)
+        let requestDictionary: [String: AnyObject] = ["path": correctPath(path)! as NSString]
+        request.httpBody = Data(jsonDictionary: requestDictionary)
        let task = session.dataTask(with: request, completionHandler: { (data, response, error) in
+            var serverError: FileProviderDropboxError?
+            var fileObject: DropboxFileObject?
            if let response = response as? HTTPURLResponse {
                let code = FileProviderHTTPErrorCode(rawValue: response.statusCode)
-                let dbError: FileProviderDropboxError? = code != nil ? FileProviderDropboxError(code: code!, path: path ?? fromPath ?? "", errorDescription: String(data: data ?? Data(), encoding: .utf8)) : nil
-                defer {
-                    self.delegateNotify(operation, error: error ?? dbError)
+                serverError = code != nil ? FileProviderDropboxError(code: code!, path: path, errorDescription: String(data: data ?? Data(), encoding: .utf8)) : nil
+                if let json = data?.deserializeJSON(), let file = DropboxFileObject(json: json) {
+                    fileObject = file
                }
-                /*if let data = data, let jsonStr = String(data: data, encoding: NSUTF8StringEncoding) {
-                 let json = self.jsonToDictionary(jsonStr)
-                 }*/
-                completionHandler?(dbError)
-                return
            }
-            completionHandler?(error)
+            completionHandler(fileObject, serverError ?? error)
        }) 
        task.resume()
-        return RemoteOperationHandle(tasks: [task])
    }
    
-    public func copyItem(localFile: URL, to toPath: String, completionHandler: SimpleCompletionHandler) -> OperationHandle? {
-        guard fileOperationDelegate?.fileProvider(self, shouldDoOperation: .copy(source: localFile.absoluteString, destination: toPath)) ?? true == true else {
-            return nil
-        }
-        guard let data = try? Data(contentsOf: localFile) else {
-            let error = throwError(localFile.absoluteString, code: URLError.fileDoesNotExist as FoundationErrorEnum)
-            completionHandler?(error)
-            return nil
-        }
-        return upload_simple(toPath, data: data, overwrite: true, operation: .copy(source: localFile.absoluteString, destination: toPath), completionHandler: completionHandler)
-    }
-    
-    public func copyItem(path: String, toLocalURL destURL: URL, completionHandler: SimpleCompletionHandler) -> OperationHandle? {
-        guard fileOperationDelegate?.fileProvider(self, shouldDoOperation: .copy(source: path, destination: destURL.absoluteString)) ?? true == true else {
-            return nil
-        }
-        let url = URL(string: "https://content.dropboxapi.com/2/files/download")!
+    open override func storageProperties(completionHandler: @escaping ((_ total: Int64, _ used: Int64) -> Void)) {
+        let url = URL(string: "users/get_space_usage", relativeTo: apiURL)!
        var request = URLRequest(url: url)
-        request.httpMethod = "GET"
-        request.setValue("Bearer \(credential?.password ?? "")", forHTTPHeaderField: "Authorization")
-        request.setValue("application/json", forHTTPHeaderField: "Content-Type")
-        let requestDictionary = ["path": path as NSString]
-        request.setValue(dictionaryToJSON(requestDictionary), forHTTPHeaderField: "Dropbox-API-Arg")
-        let task = session.downloadTask(with: request, completionHandler: { (cacheURL, response, error) in
-            guard let cacheURL = cacheURL, let httpResponse = response as? HTTPURLResponse , httpResponse.statusCode < 300 else {
-                let code = FileProviderHTTPErrorCode(rawValue: (response as? HTTPURLResponse)?.statusCode ?? -1)
-                let dbError: FileProviderDropboxError? = code != nil ? FileProviderDropboxError(code: code!, path: path, errorDescription: nil) : nil
-                completionHandler?(dbError ?? error)
-                return
+        request.httpMethod = "POST"
+        request.set(httpAuthentication: credential, with: .oAuth2)
+        let task = session.dataTask(with: request, completionHandler: { (data, response, error) in
+            var totalSize: Int64 = -1
+            var usedSize: Int64 = 0
+            if let json = data?.deserializeJSON() {
+                totalSize = ((json["allocation"] as? NSDictionary)?["allocated"] as? NSNumber)?.int64Value ?? -1
+                usedSize = (json["used"] as? NSNumber)?.int64Value ?? 0
            }
-            do {
-                try FileManager.default.moveItem(at: cacheURL, to: destURL)
-                completionHandler?(nil)
-            } catch let e {
-                completionHandler?(e)
-            }
-        })
-        task.taskDescription = dictionaryToJSON(["type": "Copy" as NSString, "source": path as NSString, "dest": destURL.absoluteString as NSString])
+            completionHandler(totalSize, usedSize)
+        }) 
        task.resume()
-        return RemoteOperationHandle(tasks: [task])
-    }
-}
-
-extension DropboxFileProvider: FileProviderReadWrite {
-    public func contents(path: String, completionHandler: @escaping ((_ contents: Data?, _ error: Error?) -> Void)) -> OperationHandle? {
-        return self.contents(path: path, offset: 0, length: -1, completionHandler: completionHandler)
    }
    
-    public func contents(path: String, offset: Int64, length: Int, completionHandler: @escaping ((_ contents: Data?, _ error: Error?) -> Void)) -> OperationHandle? {
-        let url = URL(string: "https://content.dropboxapi.com/2/files/download")!
-        var request = URLRequest(url: url)
-        request.httpMethod = "GET"
-        request.setValue("Bearer \(credential?.password ?? "")", forHTTPHeaderField: "Authorization")
-        if length > 0 {
-            request.setValue("bytes=\(offset)-\(offset + length)", forHTTPHeaderField: "Range")
-        } else if offset > 0 && length < 0 {
-            request.setValue("bytes=\(offset)-", forHTTPHeaderField: "Range")
-        }
-        let requestDictionary = ["path": path]
-        request.setValue(dictionaryToJSON(requestDictionary as [String : AnyObject]), forHTTPHeaderField: "Dropbox-API-Arg")
-        let task = session.dataTask(with: request, completionHandler: { (datam, response, error) in
-            guard let data = datam, let httpResponse = response as? HTTPURLResponse , httpResponse.statusCode < 300 else {
-                let code = FileProviderHTTPErrorCode(rawValue: (response as? HTTPURLResponse)?.statusCode ?? -1)
-                let dbError: FileProviderDropboxError? = code != nil ? FileProviderDropboxError(code: code!, path: path, errorDescription: String(data: datam ?? Data(), encoding: .utf8)) : nil
-                completionHandler(nil, dbError ?? error)
-                return
-            }
-            completionHandler(data, error)
-        })
-        task.resume()
-        return RemoteOperationHandle(tasks: [task])
-    }
-    
-    public func writeContents(path: String, contents data: Data, atomically: Bool = false, completionHandler: SimpleCompletionHandler) -> OperationHandle? {
-        guard fileOperationDelegate?.fileProvider(self, shouldDoOperation: .modify(path: path)) ?? true == true else {
-            return nil
-        }
-        // FIXME: remove 150MB restriction
-        return upload_simple(path, data: data, overwrite: true, operation: .modify(path: path), completionHandler: completionHandler)
-    }
-    
-    public func searchFiles(path: String, recursive: Bool, query: String, foundItemHandler: ((FileObject) -> Void)?, completionHandler: @escaping ((_ files: [FileObject], _ error: Error?) -> Void)) {
+    open override func searchFiles(path: String, recursive: Bool, query: NSPredicate, foundItemHandler: ((FileObject) -> Void)?, completionHandler: @escaping ((_ files: [FileObject], _ error: Error?) -> Void)) -> Progress? {
+        let progress = Progress(parent: nil, userInfo: nil)
        var foundFiles = [DropboxFileObject]()
-        search(path, query: query, foundItem: { (file) in
-            foundFiles.append(file)
-            foundItemHandler?(file)
+        if let queryStr = query.findValue(forKey: "name", operator: .beginsWith) as? String {
+            // Dropbox only support searching for file names begin with query in non-enterprise accounts.
+            // We will use it if there is a `name BEGINSWITH[c] "query"` in predicate, then filter to form final result.
+            search(path, query: queryStr, progress: progress, foundItem: { (file) in
+                if query.evaluate(with: file.mapPredicate()) {
+                    foundFiles.append(file)
+                    foundItemHandler?(file)
+                }
            }, completionHandler: { (error) in
                completionHandler(foundFiles, error)
-        })
+            })
+        } else {
+            // Dropbox doesn't support searching attributes natively. The workaround is to fallback to listing all files
+            // and filter it locally. It may have a network burden in case there is many files in Dropbox, so please use it concisely.
+            list(path, recursive: true, progress: progress, progressHandler: { (files, _, error) in
+                for file in files where query.evaluate(with: file.mapPredicate()) {
+                    foundItemHandler?(file)
+                }
+            }, completionHandler: { (files, _, error) in
+                let predicatedFiles = files.filter { query.evaluate(with: $0.mapPredicate()) }
+                completionHandler(predicatedFiles, error)
+            })
+        }
+        return progress
    }
    
+    open override func isReachable(completionHandler: @escaping (Bool) -> Void) {
+        self.storageProperties { total, _ in
+            completionHandler(total > 0)
+        }
+    }
+    
+    override func request(for operation: FileOperationType, overwrite: Bool, attributes: [URLResourceKey : Any]) -> URLRequest {
+        // content operations
+        var request: URLRequest
+        switch operation {
+        case .copy(source: let source, destination: let dest) where dest.lowercased().hasPrefix("file://"):
+            let url = URL(string: "files/download", relativeTo: contentURL)!
+            request = URLRequest(url: url)
+            request.set(httpAuthentication: credential, with: .oAuth2)
+            request.set(dropboxArgKey: ["path": correctPath(source)! as NSString])
+        case .fetch(let path):
+            let url = URL(string: "files/download", relativeTo: contentURL)!
+            request = URLRequest(url: url)
+            request.set(httpAuthentication: credential, with: .oAuth2)
+            request.set(dropboxArgKey: ["path": correctPath(path)! as NSString])
+        case .copy(source: let source, destination: let dest) where source.lowercased().hasPrefix("file://"):
+            var requestDictionary = [String: AnyObject]()
+            let url: URL = URL(string: "files/upload", relativeTo: contentURL)!
+            requestDictionary["path"] = correctPath(dest) as NSString?
+            requestDictionary["mode"] = (overwrite ? "overwrite" : "add") as NSString
+            requestDictionary["client_modified"] = (attributes[.contentModificationDateKey] as? Date)?.rfc3339utc() as NSString?
+            request = URLRequest(url: url)
+            request.httpMethod = "POST"
+            request.set(httpAuthentication: credential, with: .oAuth2)
+            request.set(contentType: .stream)
+            request.set(dropboxArgKey: requestDictionary)
+        case .modify(let path):
+            var requestDictionary = [String: AnyObject]()
+            let url: URL = URL(string: "files/upload", relativeTo: contentURL)!
+            requestDictionary["path"] = correctPath(path) as NSString?
+            requestDictionary["mode"] = (overwrite ? "overwrite" : "add") as NSString
+            requestDictionary["client_modified"] = (attributes[.contentModificationDateKey] as? Date)?.rfc3339utc() as NSString?
+            request = URLRequest(url: url)
+            request.httpMethod = "POST"
+            request.set(httpAuthentication: credential, with: .oAuth2)
+            request.set(contentType: .stream)
+            request.set(dropboxArgKey: requestDictionary)
+        default: // modify, link, fetch
+            return self.apiRequest(for: operation)
+        }
+        return request
+    }
+    
+    func apiRequest(for operation: FileOperationType) -> URLRequest {
+        let url: String
+        let sourcePath = operation.source
+        let destPath = operation.destination
+        switch operation {
+        case .create:
+            url = "files/create_folder"
+        case .copy:
+            url = "files/copy"
+        case .move:
+            url = "files/move"
+        case .remove:
+            url = "files/delete"
+        default: // modify, link, fetch
+            fatalError("Unimplemented operation \(operation.description) in \(#file)")
+        }
+        var request = URLRequest(url: URL(string: url, relativeTo: apiURL)!)
+        request.httpMethod = "POST"
+        request.set(httpAuthentication: credential, with: .oAuth2)
+        request.set(contentType: .json)
+        var requestDictionary = [String: AnyObject]()
+        if let dest = correctPath(destPath) as NSString? {
+            requestDictionary["from_path"] = correctPath(sourcePath) as NSString?
+            requestDictionary["to_path"] = dest
+        } else {
+            requestDictionary["path"] = correctPath(sourcePath) as NSString?
+        }
+        request.httpBody = Data(jsonDictionary: requestDictionary)
+        return request
+    }
+    
+    override func serverError(with code: FileProviderHTTPErrorCode, path: String?, data: Data?) -> FileProviderHTTPError {
+        return FileProviderDropboxError(code: code, path: path ?? "", errorDescription: data.flatMap({ String(data: $0, encoding: .utf8) }))
+    }
+    
+    override func upload_simple(_ targetPath: String, request: URLRequest, data: Data?, localFile: URL?, operation: FileOperationType, completionHandler: SimpleCompletionHandler) -> Progress? {
+        let size = data?.count ?? Int((try? localFile?.resourceValues(forKeys: [.fileSizeKey]))??.fileSize ?? -1)
+        if size > 150 * 1024 * 1024 {
+            let error = FileProviderDropboxError(code: .payloadTooLarge, path: targetPath, errorDescription: nil)
+            completionHandler?(error)
+            self.delegateNotify(operation, error: error)
+            return nil
+        }
+        
+        return super.upload_simple(targetPath, request: request, data: data, localFile: localFile, operation: operation, completionHandler: completionHandler)
+    }
+}
+
+extension DropboxFileProvider {
+    /*
    fileprivate func registerNotifcation(path: String, eventHandler: (() -> Void)) {
        /* There is two ways to monitor folders changing in Dropbox. Either using webooks
         * which means you have to implement a server to translate it to push notifications
@@ -283,67 +243,222 @@ extension DropboxFileProvider: FileProviderReadWrite {
    fileprivate func unregisterNotifcation(path: String) {
        NotImplemented()
    }
+    */
+    // TODO: Implement /get_account & /get_current_account
+}
+
+extension DropboxFileProvider: FileProviderSharing {
+    open func publicLink(to path: String, completionHandler: @escaping ((_ link: URL?, _ attribute: FileObject?, _ expiration: Date?, _ error: Error?) -> Void)) {
+        let url = URL(string: "files/get_temporary_link", relativeTo: apiURL)!
+        var request = URLRequest(url: url)
+        request.httpMethod = "POST"
+        request.set(httpAuthentication: credential, with: .oAuth2)
+        request.set(contentType: .json)
+        let requestDictionary: [String: AnyObject] = ["path": correctPath(path)! as NSString]
+        request.httpBody = Data(jsonDictionary: requestDictionary)
+        let task = session.dataTask(with: request, completionHandler: { (data, response, error) in
+            var serverError: FileProviderDropboxError?
+            var link: URL?
+            var fileObject: DropboxFileObject?
+            if let response = response as? HTTPURLResponse {
+                let code = FileProviderHTTPErrorCode(rawValue: response.statusCode)
+                serverError = code != nil ? FileProviderDropboxError(code: code!, path: path, errorDescription: String(data: data ?? Data(), encoding: .utf8)) : nil
+                if let json = data?.deserializeJSON() {
+                    if let linkStr = json["link"] as? String {
+                        link = URL(string: linkStr)
+                    }
+                    if let attribDic = json["metadata"] as? [String: AnyObject] {
+                        fileObject = DropboxFileObject(json: attribDic)
+                    }
+                }
+            }
+            
+            let expiration: Date? = link != nil ? Date(timeIntervalSinceNow: 4 * 60 * 60) : nil
+            completionHandler(link, fileObject, expiration, serverError ?? error)
+        })
+        task.resume()
+    }
    
-    // TODO: Implement /copy_reference, /get_temporary_link, /save_url, /get_account & /get_current_account
+    /**
+     Downloads a file from remote url to designated path asynchronously.
+     
+     - Parameters:
+       - remoteURL: a valid remote url to file.
+       - to: Destination path of file, including file/directory name.
+       - completionHandler: a closure with result of directory entries or error.
+         - `jobId`: Job ID returned by Dropbox to monitor the copy/download progress.
+         - `attribute`: A `FileObject` containing the attributes of the item.
+         - `error`: Error returned by Dropbox.
+     */
+    open func copyItem(remoteURL: URL, to toPath: String, completionHandler: @escaping ((_ jobId: String?, _ attribute: DropboxFileObject?, _ error: Error?) -> Void)) {
+        if remoteURL.isFileURL {
+            completionHandler(nil, nil, self.throwError(remoteURL.path, code: URLError.badURL))
+            return
+        }
+        let url = URL(string: "files/save_url", relativeTo: apiURL)!
+        var request = URLRequest(url: url)
+        request.httpMethod = "POST"
+        request.set(httpAuthentication: credential, with: .oAuth2)
+        request.set(contentType: .json)
+        let requestDictionary: [String: AnyObject] = ["path": correctPath(toPath)! as NSString, "url" : remoteURL.absoluteString as NSString]
+        request.httpBody = Data(jsonDictionary: requestDictionary)
+        let task = session.dataTask(with: request, completionHandler: { (data, response, error) in
+            var serverError: FileProviderDropboxError?
+            var jobId: String?
+            var fileObject: DropboxFileObject?
+            if let response = response as? HTTPURLResponse {
+                let code = FileProviderHTTPErrorCode(rawValue: response.statusCode)
+                serverError = code != nil ? FileProviderDropboxError(code: code!, path: toPath, errorDescription: String(data: data ?? Data(), encoding: .utf8)) : nil
+                if let json = data?.deserializeJSON() {
+                    jobId = json["async_job_id"] as? String
+                    if let attribDic = json["metadata"] as? [String: AnyObject] {
+                        fileObject = DropboxFileObject(json: attribDic)
+                    }
+                }
+            }
+            completionHandler(jobId, fileObject, serverError ?? error)
+        })
+        task.resume()
+    }
+    
+    /**
+     Copys a file from another user Dropbox storage to designated path asynchronously.
+     
+     - Parameters:
+       - reference: a valid reference string from another user via `copy_reference/get` REST method.
+       - to: Destination path of file, including file/directory name.
+       - completionHandler: If an error parameter was provided, a presentable `Error` will be returned.
+     */
+    open func copyItem(reference: String, to toPath: String, completionHandler: SimpleCompletionHandler) {
+        let url = URL(string: "files/copy_reference/save", relativeTo: apiURL)!
+        var request = URLRequest(url: url)
+        request.httpMethod = "POST"
+        request.set(httpAuthentication: credential, with: .oAuth2)
+        request.set(contentType: .json)
+        let requestDictionary: [String: AnyObject] = ["path": correctPath(toPath)! as NSString, "copy_reference" : reference as NSString]
+        request.httpBody = Data(jsonDictionary: requestDictionary)
+        let task = session.dataTask(with: request, completionHandler: { (data, response, error) in
+            var serverError: FileProviderDropboxError?
+            if let response = response as? HTTPURLResponse {
+                let code = FileProviderHTTPErrorCode(rawValue: response.statusCode)
+                serverError = code != nil ? FileProviderDropboxError(code: code!, path: toPath, errorDescription: String(data: data ?? Data(), encoding: .utf8)) : nil
+            }
+            completionHandler?(serverError ?? error)
+        })
+        task.resume()
+    }
 }

 extension DropboxFileProvider: ExtendedFileProvider {
-    public func thumbnailOfFileSupported(path: String) -> Bool {
+    open func thumbnailOfFileSupported(path: String) -> Bool {
        switch (path as NSString).pathExtension.lowercased() {
        case "jpg", "jpeg", "gif", "bmp", "png", "tif", "tiff":
            return true
-        /*case "doc", "docx", "docm", "xls", "xlsx", "xlsm":
+        case "doc", "docx", "docm", "xls", "xlsx", "xlsm":
            return true
        case  "ppt", "pps", "ppsx", "ppsm", "pptx", "pptm":
            return true
        case "rtf":
-            return true*/
+            return true
        default:
            return false
        }
    }
    
-    public func propertiesOfFileSupported(path: String) -> Bool {
-        return false
+    open func propertiesOfFileSupported(path: String) -> Bool {
+        let fileExt = (path as NSString).pathExtension.lowercased()
+        switch fileExt {
+        case "jpg", "jpeg", "bmp", "gif", "png", "tif", "tiff":
+            return true
+        /*case "mp3", "aac", "m4a":
+            return true*/
+        case "mp4", "mpg", "3gp", "mov", "avi":
+            return true
+        default:
+            return false
+        }
    }
-    
-    public func thumbnailOfFile(path: String, dimension: CGSize, completionHandler: @escaping ((_ image: ImageClass?, _ error: Error?) -> Void)) {
+        
+    /// Default value for dimension is 64x64, according to Dropbox documentation
+    open func thumbnailOfFile(path: String, dimension: CGSize?, completionHandler: @escaping ((_ image: ImageClass?, _ error: Error?) -> Void)) {
        let url: URL
+        let thumbAPI: Bool
        switch (path as NSString).pathExtension.lowercased() {
        case "jpg", "jpeg", "gif", "bmp", "png", "tif", "tiff":
-            url = URL(string: "https://content.dropboxapi.com/2/files/get_thumbnail")!
-        /*case "doc", "docx", "docm", "xls", "xlsx", "xlsm":
+            url = URL(string: "files/get_thumbnail", relativeTo: contentURL)!
+            thumbAPI = true
+        case "doc", "docx", "docm", "xls", "xlsx", "xlsm":
            fallthrough
        case  "ppt", "pps", "ppsx", "ppsm", "pptx", "pptm":
            fallthrough
        case "rtf":
-            url = NSURL(string: "https://content.dropboxapi.com/2/files/get_preview")!*/
+            url = URL(string: "files/get_preview", relativeTo: contentURL)!
+            thumbAPI = false
        default:
            return
        }
        var request = URLRequest(url: url)
-        request.setValue("Bearer \(credential?.password ?? "")", forHTTPHeaderField: "Authorization")
-        var requestDictionary = ["path": path as NSString]
-        requestDictionary["format"] = "jpeg" as NSString
-        requestDictionary["size"] = "w\(Int(dimension.width))h\(Int(dimension.height))" as NSString
-        request.setValue(dictionaryToJSON(requestDictionary), forHTTPHeaderField: "Dropbox-API-Arg")
-        self.session.dataTask(with: request, completionHandler: { (data, response, error) in
+        request.set(httpAuthentication: credential, with: .oAuth2)
+        var requestDictionary: [String: AnyObject] = ["path": path as NSString]
+        if thumbAPI {
+            requestDictionary["format"] = "jpeg" as NSString
+            let size: String
+            switch dimension?.height ?? 64 {
+            case 0...32:    size = "w32h32"
+            case 33...64:   size = "w64h64"
+            case 65...128:  size = "w128h128"
+            case 129...480: size = "w640h480"
+            default: size = "w1024h768"
+            }
+            requestDictionary["size"] = size as NSString
+        }
+        request.set(dropboxArgKey: requestDictionary)
+        let task = self.session.dataTask(with: request, completionHandler: { (data, response, error) in
            var image: ImageClass? = nil
-            if let r = response as? HTTPURLResponse, let result = r.allHeaderFields["Dropbox-API-Result"] as? String, let jsonResult = jsonToDictionary(result) {
+            if let r = response as? HTTPURLResponse, let result = r.allHeaderFields["Dropbox-API-Result"] as? String, let jsonResult = result.deserializeJSON() {
                if jsonResult["error"] != nil {
                    completionHandler(nil, self.throwError(path, code: URLError.cannotDecodeRawData as FoundationErrorEnum))
                }
            }
            if let data = data {
-                image = ImageClass(data: data)
+                if data.isPDF, let pageImage = DropboxFileProvider.convertToImage(pdfData: data) {
+                    image = pageImage
+                } else if let contentType = (response as? HTTPURLResponse)?.allHeaderFields["Content-Type"] as? String, contentType.contains("text/html") {
+                     // TODO: Implement converting html returned type of get_preview to image
+                } else if let fetchedimage = ImageClass(data: data){
+                    if let dimension = dimension {
+                        image = DropboxFileProvider.scaleDown(image: fetchedimage, toSize: dimension)
+                    } else {
+                        image = fetchedimage
+                    }
+                }
            }
            completionHandler(image, error)
-        }) 
+        })
+        task.resume()
    }
    
-    public func propertiesOfFile(path: String, completionHandler: @escaping ((_ propertiesDictionary: [String : Any], _ keys: [String], _ error: Error?) -> Void)) {
-        NotImplemented()
+    open func propertiesOfFile(path: String, completionHandler: @escaping ((_ propertiesDictionary: [String : Any], _ keys: [String], _ error: Error?) -> Void)) {
+        let url = URL(string: "files/get_metadata", relativeTo: apiURL)!
+        var request = URLRequest(url: url)
+        request.httpMethod = "POST"
+        request.set(httpAuthentication: credential, with: .oAuth2)
+        request.set(contentType: .json)
+        let requestDictionary: [String: AnyObject] = ["path": correctPath(path)! as NSString, "include_media_info": NSNumber(value: true)]
+        request.httpBody = Data(jsonDictionary: requestDictionary)
+        let task = session.dataTask(with: request, completionHandler: { (data, response, error) in
+            var serverError: FileProviderDropboxError?
+            var dic = [String: Any]()
+            var keys = [String]()
+            if let response = response as? HTTPURLResponse {
+                let code = FileProviderHTTPErrorCode(rawValue: response.statusCode)
+                serverError = code != nil ? FileProviderDropboxError(code: code!, path: path, errorDescription: String(data: data ?? Data(), encoding: .utf8)) : nil
+                if let json = data?.deserializeJSON(), let properties = (json["media_info"] as? [String: Any])?["metadata"] as? [String: Any] {
+                    (dic, keys) = self.mapMediaInfo(properties)
+                }
+            }
+            completionHandler(dic, keys, serverError ?? error)
+        })
+        task.resume()
    }
 }
-
-extension DropboxFileProvider: FileProvider {}
@@ -2,158 +2,160 @@
 //  DropboxHelper.swift
 //  FileProvider
 //
-//  Created by Amir Abbas Mousavian on 5/18/95.
-//
+//  Created by Amir Abbas Mousavian.
+//  Copyright © 2016 Mousavian. Distributed under MIT license.
 //

 import Foundation

-public struct FileProviderDropboxError: Error, CustomStringConvertible {
+/// Error returned by Dropbox server when trying to access or do operations on a file or folder.
+public struct FileProviderDropboxError: FileProviderHTTPError {
    public let code: FileProviderHTTPErrorCode
    public let path: String
    public let errorDescription: String?
-    
-    public var description: String {
-        return code.description
-    }
 }

+/// Containts path, url and attributes of a Dropbox file or resource.
 public final class DropboxFileObject: FileObject {
-    public let serverTime: Date?
-    public let id: String?
-    public let rev: String?
-    
-    // codebeat:disable[ARITY]
-    public init(name: String, path: String, size: Int64 = -1, serverTime: Date? = nil, modifiedDate: Date? = nil, fileType: FileType = .regular, isHidden: Bool = false, isReadOnly: Bool = false, id: String? = nil, rev: String? = nil) {
-        self.serverTime = serverTime
-        self.id = id
-        self.rev = rev
-        super.init(absoluteURL: URL(string: path), name: name, path: path, size: size, createdDate: nil, modifiedDate: modifiedDate, fileType: fileType, isHidden: isHidden, isReadOnly: isReadOnly)
+    internal convenience init? (jsonStr: String) {
+        guard let json = jsonStr.deserializeJSON() else { return nil }
+        self.init(json: json)
+    }
+    
+    internal init? (json: [String: AnyObject]) {
+        guard let name = json["name"] as? String else { return nil }
+        guard let path = json["path_display"] as? String else { return nil }
+        super.init(url: nil, name: name, path: path)
+        self.size = (json["size"] as? NSNumber)?.int64Value ?? -1
+        self.serverTime = Date(rfcString: json["server_modified"] as? String ?? "")
+        self.modifiedDate = Date(rfcString: json["client_modified"] as? String ?? "")
+        self.type = (json[".tag"] as? String) == "folder" ? .directory : .regular
+        self.isReadOnly = (json["sharing_info"]?["read_only"] as? NSNumber)?.boolValue ?? false
+        self.id = json["id"] as? String
+        self.rev = json["rev"] as? String
+    }
+    
+    /// The time contents of file has been modified on server, returns nil if not set
+    open internal(set) var serverTime: Date? {
+        get {
+            return allValues[.serverDateKey] as? Date
+        }
+        set {
+            allValues[.serverDateKey] = newValue
+        }
+    }
+    
+    /// The document identifier is a value assigned by the Dropbox to a file.
+    /// This value is used to identify the document regardless of where it is moved on a volume.
+    /// The identifier persists across system restarts.
+    open internal(set) var id: String? {
+        get {
+            return allValues[.documentIdentifierKey] as? String
+        }
+        set {
+            allValues[.documentIdentifierKey] = newValue
+        }
+    }
+    
+    /// The revision of file, which changes when a file contents are modified.
+    /// Changes to attributes or other file metadata do not change the identifier.
+    open internal(set) var rev: String? {
+        get {
+            return allValues[.generationIdentifierKey] as? String
+        }
+        set {
+            allValues[.generationIdentifierKey] = newValue
+        }
    }
-    // codebeat:enable[ARITY]
 }

 // codebeat:disable[ARITY]
 internal extension DropboxFileProvider {
-    func list(_ path: String, cursor: String? = nil, prevContents: [DropboxFileObject] = [], recursive: Bool = false, completionHandler: @escaping ((_ contents: [FileObject], _ cursor: String?, _ error: Error?) -> Void)) {
+    
+    
+    func list(_ path: String, cursor: String? = nil, prevContents: [DropboxFileObject] = [], recursive: Bool = false, session: URLSession? = nil, progress: Progress, progressHandler: ((_ contents: [FileObject], _ nextCursor: String?, _ error: Error?) -> Void)? = nil, completionHandler: @escaping ((_ contents: [FileObject], _ cursor: String?, _ error: Error?) -> Void)) {
+        if progress.isCancelled { return }
+        
        var requestDictionary = [String: AnyObject]()
        let url: URL
        if let cursor = cursor {
-            url = URL(string: "https://api.dropboxapi.com/2/files/list_folder/continue")!
+            url = URL(string: "files/list_folder/continue", relativeTo: apiURL)!
            requestDictionary["cursor"] = cursor as NSString?
        } else {
-            url = URL(string: "https://api.dropboxapi.com/2/files/list_folder")!
+            url = URL(string: "files/list_folder", relativeTo: apiURL)!
            requestDictionary["path"] = correctPath(path) as NSString?
            requestDictionary["recursive"] = recursive as NSNumber?
        }
        var request = URLRequest(url: url)
        request.httpMethod = "POST"
-        request.setValue("Bearer \(credential?.password ?? "")", forHTTPHeaderField: "Authorization")
-        request.setValue("application/json", forHTTPHeaderField: "Content-Type")
-        request.httpBody = dictionaryToJSON(requestDictionary)?.data(using: .utf8)
-        let task = session.dataTask(with: request, completionHandler: { (data, response, error) in
+        request.set(httpAuthentication: credential, with: .oAuth2)
+        request.set(contentType: .json)
+        request.httpBody = Data(jsonDictionary: requestDictionary)
+        let task = (session ?? self.session).dataTask(with: request, completionHandler: { (data, response, error) in
            var responseError: FileProviderDropboxError?
+            var files = [DropboxFileObject]()
            if let code = (response as? HTTPURLResponse)?.statusCode , code >= 300, let rCode = FileProviderHTTPErrorCode(rawValue: code) {
                responseError = FileProviderDropboxError(code: rCode, path: path, errorDescription: String(data: data ?? Data(), encoding: .utf8))
            }
-            if let data = data, let jsonStr = String(data: data, encoding: .utf8) {
-                let json = jsonToDictionary(jsonStr)
-                if let entries = json?["entries"] as? [AnyObject] , entries.count > 0 {
-                    var files = prevContents
+            if let json = data?.deserializeJSON() {
+                if let entries = json["entries"] as? [AnyObject] , entries.count > 0 {
+                    files.reserveCapacity(entries.count)
                    for entry in entries {
-                        if let entry = entry as? [String: AnyObject], let file = self.mapToFileObject(entry) {
+                        if let entry = entry as? [String: AnyObject], let file = DropboxFileObject(json: entry) {
                            files.append(file)
+                            progress.totalUnitCount = Int64(files.count)
                        }
                    }
-                    let ncursor = json?["cursor"] as? String
-                    let hasmore = (json?["has_more"] as? NSNumber)?.boolValue ?? false
-                    if hasmore {
-                        self.list(path, cursor: ncursor, prevContents: files, completionHandler: completionHandler)
-                    } else {
-                        completionHandler(files, ncursor, responseError ?? error)
+                    let ncursor = json["cursor"] as? String
+                    let hasmore = (json["has_more"] as? NSNumber)?.boolValue ?? false
+                    if hasmore && !progress.isCancelled {
+                        progressHandler?(files, ncursor, responseError ?? error)
+                        self.list(path, cursor: ncursor, prevContents: prevContents + files, progress: progress, completionHandler: completionHandler)
+                        return
                    }
-                    return
                }
            }
-            completionHandler([], nil, responseError ?? error)
-        }) 
-        task.resume()
-    }
-    
-    func upload_simple(_ targetPath: String, data: Data, modifiedDate: Date = Date(), overwrite: Bool, operation: FileOperationType, completionHandler: SimpleCompletionHandler) -> OperationHandle? {
-        assert(data.count < 150*1024*1024, "Maximum size of allowed size to upload is 150MB")
-        var requestDictionary = [String: AnyObject]()
-        let url: URL
-        url = URL(string: "https://content.dropboxapi.com/2/files/upload")!
-        requestDictionary["path"] = correctPath(targetPath) as NSString?
-        requestDictionary["mode"] = (overwrite ? "overwrite" : "add") as NSString
-        let dateFormatter = DateFormatter()
-        dateFormatter.dateFormat = "yyyy'-'MM'-'dd'T'HH':'mm':'ssz"
-        requestDictionary["client_modified"] = dateFormatter.string(from: modifiedDate) as NSString
-        var request = URLRequest(url: url)
-        request.httpMethod = "POST"
-        request.setValue("Bearer \(credential?.password ?? "")", forHTTPHeaderField: "Authorization")
-        request.setValue("application/octet-stream", forHTTPHeaderField: "Content-Type")
-        request.setValue(dictionaryToJSON(requestDictionary), forHTTPHeaderField: "Dropbox-API-Arg")
-        request.httpBody = data
-        let task = session.uploadTask(with: request, from: data, completionHandler: { (data, response, error) in
-            var responseError: FileProviderDropboxError?
-            if let code = (response as? HTTPURLResponse)?.statusCode , code >= 300, let rCode = FileProviderHTTPErrorCode(rawValue: code) {
-                responseError = FileProviderDropboxError(code: rCode, path: targetPath, errorDescription: String(data: data ?? Data(), encoding: .utf8))
-            }
-            defer {
-                self.delegateNotify(.create(path: targetPath), error: responseError ?? error)
-            }
-            completionHandler?(responseError ?? error)
-        }) 
-        var dic: [String: AnyObject] = ["type": operation.description as NSString]
-        switch operation {
-        case .create(path: let s):
-            dic["source"] = s as NSString
-        case .copy(source: let s, destination: let d):
-            dic["source"] = s as NSString
-            dic["dest"] = d as NSString
-        case .modify(path: let s):
-            dic["source"] = s as NSString
-        case .move(source: let s, destination: let d):
-            dic["source"] = s as NSString
-            dic["dest"] = d as NSString
-        default:
-            break
+            progressHandler?(files, nil, responseError ?? error)
+            completionHandler(prevContents + files, nil, responseError ?? error)
+        })
+        progress.cancellationHandler = { [weak task] in
+            task?.cancel()
        }
-        task.taskDescription = dictionaryToJSON(dic)
+        progress.setUserInfoObject(Date(), forKey: .startingTimeKey)
+        task.taskDescription = FileOperationType.fetch(path: path).json
        task.resume()
-        return RemoteOperationHandle(tasks: [task])
    }
    
-    func search(_ startPath: String = "", query: String, start: Int = 0, maxResultPerPage: Int = 25, maxResults: Int = -1, foundItem:@escaping ((_ file: DropboxFileObject) -> Void), completionHandler: @escaping ((_ error: Error?) -> Void)) {
-        let url = URL(string: "https://api.dropboxapi.com/2/files/search")!
+    func search(_ startPath: String = "", query: String, start: Int = 0, maxResultPerPage: Int = 25, maxResults: Int = -1, progress: Progress, foundItem:@escaping ((_ file: DropboxFileObject) -> Void), completionHandler: @escaping ((_ error: Error?) -> Void)) {
+        if progress.isCancelled { return }
+        
+        let url = URL(string: "files/search", relativeTo: apiURL)!
        var request = URLRequest(url: url)
        request.httpMethod = "POST"
-        request.setValue("Bearer \(credential?.password ?? "")", forHTTPHeaderField: "Authorization")
-        request.setValue("application/json", forHTTPHeaderField: "Content-Type")
+        request.set(httpAuthentication: credential, with: .oAuth2)
+        request.set(contentType: .json)
        var requestDictionary: [String: AnyObject] = ["path": startPath as NSString]
        requestDictionary["query"] = query as NSString
        requestDictionary["start"] = start as NSNumber
        requestDictionary["max_results"] = maxResultPerPage as NSNumber
-        request.httpBody = dictionaryToJSON(requestDictionary)?.data(using: .utf8)
+        request.httpBody = Data(jsonDictionary: requestDictionary)
        let task = session.dataTask(with: request, completionHandler: { (data, response, error) in
            var responseError: FileProviderDropboxError?
            if let code = (response as? HTTPURLResponse)?.statusCode , code >= 300, let rCode = FileProviderHTTPErrorCode(rawValue: code) {
                responseError = FileProviderDropboxError(code: rCode, path: startPath, errorDescription: String(data: data ?? Data(), encoding: .utf8))
            }
-            if let data = data, let jsonStr = String(data: data, encoding: .utf8) {
-                let json = jsonToDictionary(jsonStr)
-                if let entries = json?["matches"] as? [AnyObject] , entries.count > 0 {
+            if let json = data?.deserializeJSON() {
+                if let entries = json["matches"] as? [AnyObject] , entries.count > 0 {
                    for entry in entries {
-                        if let entry = entry as? [String: AnyObject], let file = self.mapToFileObject(entry) {
+                        if let entry = entry as? [String: AnyObject], let file = DropboxFileObject(json: entry) {
                            foundItem(file)
+                            progress.completedUnitCount += 1
                        }
                    }
-                    let rstart = json?["start"] as? Int
-                    let hasmore = (json?["more"] as? NSNumber)?.boolValue ?? false
-                    if hasmore, let rstart = rstart {
-                        self.search(startPath, query: query, start: rstart + entries.count, maxResultPerPage: maxResultPerPage, foundItem: foundItem, completionHandler: completionHandler)
+                    let rstart = json["start"] as? Int
+                    let hasmore = (json["more"] as? NSNumber)?.boolValue ?? false
+                    if hasmore && !progress.isCancelled, let rstart = rstart {
+                        self.search(startPath, query: query, start: rstart + entries.count, maxResultPerPage: maxResultPerPage, progress: progress, foundItem: foundItem, completionHandler: completionHandler)
                    } else {
                        completionHandler(responseError ?? error)
                    }
@@ -161,38 +163,45 @@ internal extension DropboxFileProvider {
                }
            }
            completionHandler(responseError ?? error)
-        }) 
+        })
+        progress.cancellationHandler = { [weak task] in
+            task?.cancel()
+        }
+        progress.setUserInfoObject(Date(), forKey: .startingTimeKey)
        task.resume()
    }
 }
 // codebeat:enable[ARITY]

 internal extension DropboxFileProvider {
-    func mapToFileObject(_ jsonStr: String) -> DropboxFileObject? {
-        guard let json = jsonToDictionary(jsonStr) else { return nil }
-        return self.mapToFileObject(json)
-    }
+    static let dateFormatter = DateFormatter()
+    static let decimalFormatter = NumberFormatter()
    
-    func mapToFileObject(_ json: [String: AnyObject]) -> DropboxFileObject? {
-        guard let name = json["name"] as? String else { return nil }
-        guard let path = json["path_display"] as? String else { return nil }
-        let size = (json["size"] as? NSNumber)?.int64Value ?? -1
-        let serverTime = resolve(dateString: json["server_modified"] as? String ?? "")
-        let modifiedDate = resolve(dateString: json["client_modified"] as? String ?? "")
-        let isDirectory = (json[".tag"] as? String) == "folder"
-        let isReadonly = (json["sharing_info"]?["read_only"] as? NSNumber)?.boolValue ?? false
-        let id = json["id"] as? String
-        let rev = json["id"] as? String
-        return DropboxFileObject(name: name, path: path, size: size, serverTime: serverTime, modifiedDate: modifiedDate, fileType: isDirectory ? .directory : .regular, isReadOnly: isReadonly, id: id, rev: rev)
-    }
-    
-    func delegateNotify(_ operation: FileOperationType, error: Error?) {
-        DispatchQueue.main.async(execute: {
-            if error == nil {
-                self.delegate?.fileproviderSucceed(self, operation: operation)
-            } else {
-                self.delegate?.fileproviderFailed(self, operation: operation)
-            }
-        })
+    func mapMediaInfo(_ json: [String: Any]) -> (dictionary: [String: Any], keys: [String]) {
+        var dic = [String: Any]()
+        var keys = [String]()
+        if let dimensions = json["dimensions"] as? [String: Any], let height = dimensions["height"] as? UInt64, let width = dimensions["width"] as? UInt64 {
+            keys.append("Dimensions")
+            dic["Dimensions"] = "\(width)x\(height)"
+        }
+        if let location = json["location"] as? [String: Any], let latitude = location["latitude"] as? Double, let longitude = location["longitude"] as? Double {
+            
+            DropboxFileProvider.decimalFormatter.numberStyle = .decimal
+            DropboxFileProvider.decimalFormatter.maximumFractionDigits = 5
+            keys.append("Location")
+            let latStr = DropboxFileProvider.decimalFormatter.string(from: NSNumber(value: latitude))!
+            let longStr = DropboxFileProvider.decimalFormatter.string(from: NSNumber(value: longitude))!
+            dic["Location"] = "\(latStr), \(longStr)"
+        }
+        if let timeTakenStr = json["time_taken"] as? String, let timeTaken = Date(rfcString: timeTakenStr) {
+            keys.append("Date taken")
+            DropboxFileProvider.dateFormatter.dateFormat = "yyyy-MM-dd HH:mm:ss"
+            dic["Date taken"] = DropboxFileProvider.dateFormatter.string(from: timeTaken)
+        }
+        if let duration = json["duration"] as? UInt64 {
+            keys.append("Duration")
+            dic["Duration"] = TimeInterval(duration).formatshort
+        }
+        return (dic, keys)
    }
 }
@@ -0,0 +1,513 @@
+//
+//  ExtendedLocalFileProvider.swift
+//  FileProvider
+//
+//  Created by Amir Abbas Mousavian.
+//  Copyright © 2017 Mousavian. Distributed under MIT license.
+//
+
+import Foundation
+import ImageIO
+import CoreGraphics
+import AVFoundation
+
+extension LocalFileProvider: ExtendedFileProvider {
+    open func thumbnailOfFileSupported(path: String) -> Bool {
+        switch (path as NSString).pathExtension.lowercased() {
+        case LocalFileInformationGenerator.imageThumbnailExtensions:
+            return true
+        case LocalFileInformationGenerator.audioThumbnailExtensions:
+            return true
+        case LocalFileInformationGenerator.videoThumbnailExtensions:
+            return true
+        case LocalFileInformationGenerator.pdfThumbnailExtensions:
+            return true
+        case LocalFileInformationGenerator.officeThumbnailExtensions:
+            return true
+        case LocalFileInformationGenerator.customThumbnailExtensions:
+            return true
+        default:
+            return false
+        }
+    }
+    
+    open func propertiesOfFileSupported(path: String) -> Bool {
+        let fileExt = (path as NSString).pathExtension.lowercased()
+        switch fileExt {
+        case LocalFileInformationGenerator.imagePropertiesExtensions:
+            return LocalFileInformationGenerator.imageProperties != nil
+        case LocalFileInformationGenerator.audioPropertiesExtensions:
+            return LocalFileInformationGenerator.audioProperties != nil
+        case LocalFileInformationGenerator.videoPropertiesExtensions:
+            return LocalFileInformationGenerator.videoProperties != nil
+        case LocalFileInformationGenerator.pdfPropertiesExtensions:
+            return LocalFileInformationGenerator.pdfProperties != nil
+        case LocalFileInformationGenerator.archivePropertiesExtensions:
+            return LocalFileInformationGenerator.archiveProperties != nil
+        case LocalFileInformationGenerator.officePropertiesExtensions:
+            return LocalFileInformationGenerator.officeProperties != nil
+        case LocalFileInformationGenerator.customPropertiesExtensions:
+            return LocalFileInformationGenerator.customProperties != nil
+
+        default:
+            return false
+        }
+    }
+    
+    open func thumbnailOfFile(path: String, dimension: CGSize? = nil, completionHandler: @escaping ((_ image: ImageClass?, _ error: Error?) -> Void)) {
+        let dimension = dimension ?? CGSize(width: 64, height: 64)
+        (dispatch_queue).async {
+            var thumbnailImage: ImageClass? = nil
+            // Check cache
+            let fileURL = self.url(of: path)
+            // Create Thumbnail and cache
+            switch fileURL.pathExtension.lowercased() {
+            case LocalFileInformationGenerator.videoThumbnailExtensions:
+                thumbnailImage = LocalFileInformationGenerator.videoThumbnail(fileURL)
+            case LocalFileInformationGenerator.audioThumbnailExtensions:
+                thumbnailImage = LocalFileInformationGenerator.audioThumbnail(fileURL)
+            case LocalFileInformationGenerator.imageThumbnailExtensions:
+                thumbnailImage = LocalFileInformationGenerator.imageThumbnail(fileURL)
+            case LocalFileInformationGenerator.pdfThumbnailExtensions:
+                thumbnailImage = LocalFileInformationGenerator.pdfThumbnail(fileURL)
+            case LocalFileInformationGenerator.officeThumbnailExtensions:
+                thumbnailImage = LocalFileInformationGenerator.officeThumbnail(fileURL)
+            case LocalFileInformationGenerator.customThumbnailExtensions:
+                thumbnailImage = LocalFileInformationGenerator.customThumbnail(fileURL)
+            default:
+                completionHandler(nil, nil)
+                return
+            }
+            
+            if let image = thumbnailImage {
+                let scaledImage = LocalFileProvider.scaleDown(image: image, toSize: dimension)
+                completionHandler(scaledImage, nil)
+            }
+        }
+    }
+    
+    open func propertiesOfFile(path: String, completionHandler: @escaping ((_ propertiesDictionary: [String: Any], _ keys: [String], _ error: Error?) -> Void)) {
+        (dispatch_queue).async {
+            let fileExt = (path as NSString).pathExtension.lowercased()
+            var getter: ((_ fileURL: URL) -> (prop: [String: Any], keys: [String]))?
+            switch fileExt {
+            case LocalFileInformationGenerator.imagePropertiesExtensions:
+                getter = LocalFileInformationGenerator.imageProperties
+             case LocalFileInformationGenerator.audioPropertiesExtensions:
+                getter = LocalFileInformationGenerator.audioProperties
+            case LocalFileInformationGenerator.videoPropertiesExtensions:
+                getter = LocalFileInformationGenerator.videoProperties
+            case LocalFileInformationGenerator.pdfPropertiesExtensions:
+                getter = LocalFileInformationGenerator.pdfProperties
+            case LocalFileInformationGenerator.archivePropertiesExtensions:
+                getter = LocalFileInformationGenerator.archiveProperties
+            case LocalFileInformationGenerator.officePropertiesExtensions:
+                getter = LocalFileInformationGenerator.officeProperties
+            case LocalFileInformationGenerator.customPropertiesExtensions:
+                getter = LocalFileInformationGenerator.customProperties
+            default:
+                break
+            }
+            
+            var dic = [String: Any]()
+            var keys = [String]()
+            if let getterMethod = getter {
+                (dic, keys) = getterMethod(self.url(of: path))
+            }
+            
+            completionHandler(dic, keys, nil)
+        }
+    }
+}
+
+/// Holds supported file types and thumbnail/properties generator for specefied type of file
+public struct LocalFileInformationGenerator {
+    /// Image extensions supportes for thumbnail.
+    ///
+    /// Default: `["jpg", "jpeg", "gif", "bmp", "png", "tif", "tiff", "ico"]`
+    static public var imageThumbnailExtensions: [String]  = ["jpg", "jpeg", "gif", "bmp", "png", "tif", "tiff", "ico"]
+    
+    /// Audio and music extensions supportes for thumbnail.
+    ///
+    /// Default: `["mp3", "aac", "m4a"]`
+    static public var audioThumbnailExtensions: [String]  = ["mp3", "aac", "m4a"]
+    
+    /// Video extensions supportes for thumbnail.
+    ///
+    /// Default: `["mov", "mp4", "m4v", "mpg", "mpeg"]`
+    static public var videoThumbnailExtensions: [String]  = ["mov", "mp4", "m4v", "mpg", "mpeg"]
+    
+    /// Portable document file extensions supportes for thumbnail.
+    ///
+    /// Default: `["pdf"]`
+    static public var pdfThumbnailExtensions: [String]    = ["pdf"]
+    
+    /// Office document extensions supportes for thumbnail.
+    ///
+    /// Default: `empty`
+    static public var officeThumbnailExtensions: [String] = []
+    
+    /// Custom document extensions supportes for thumbnail.
+    ///
+    /// Default: `empty`
+    static public var customThumbnailExtensions: [String] = []
+
+    
+    /// Image extensions supportes for properties.
+    ///
+    /// Default: `["jpg", "jpeg", "gif", "bmp", "png", "tif", "tiff"]`
+    static public var imagePropertiesExtensions: [String]   = ["jpg", "jpeg", "bmp", "gif", "png", "tif", "tiff"]
+    
+    /// Audio and music extensions supportes for properties.
+    ///
+    /// Default: `["mp3", "aac", "m4a", "caf"]`
+    static public var audioPropertiesExtensions: [String]   = ["mp3", "aac", "m4a", "caf"]
+    
+    /// Video extensions supportes for properties.
+    ///
+    /// Default: `["mp4", "mpg", "3gp", "mov", "avi"]`
+    static public var videoPropertiesExtensions: [String]   = ["mp4", "mpg", "3gp", "mov", "avi"]
+    
+    /// Portable document file extensions supportes for properties.
+    ///
+    /// Default: `["pdf"]`
+    static public var pdfPropertiesExtensions: [String]     = ["pdf"]
+    
+    /// Archive extensions (like zip) supportes for properties.
+    ///
+    /// Default: `empty`
+    static public var archivePropertiesExtensions: [String] = []
+    
+    /// Office document extensions supportes for properties.
+    ///
+    /// Default: `empty`
+    static public var officePropertiesExtensions: [String]  = []
+    
+    /// Custom document extensions supportes for properties.
+    ///
+    /// Default: `empty`
+    static public var customPropertiesExtensions: [String]  = []
+    
+    /// Thumbnail generator closure for image files.
+    static public var imageThumbnail: (_ fileURL: URL) -> ImageClass? = { fileURL in
+        return ImageClass(contentsOfFile: fileURL.path)
+    }
+    
+    /// Thumbnail generator closure for audio and music files.
+    static public var audioThumbnail: (_ fileURL: URL) -> ImageClass? = { fileURL in
+        let playerItem = AVPlayerItem(url: fileURL)
+        let metadataList = playerItem.asset.commonMetadata
+        #if swift(>=4.0)
+        let commonKeyArtwork = AVMetadataKey.commonKeyArtwork
+        #else
+        let commonKeyArtwork = AVMetadataCommonKeyArtwork
+        #endif
+        for item in metadataList {
+            if item.commonKey == commonKeyArtwork {
+                if let data = item.dataValue {
+                    return ImageClass(data: data)
+                }
+            }
+        }
+        return nil
+    }
+    
+    /// Thumbnail generator closure for video files.
+    static public var videoThumbnail: (_ fileURL: URL) -> ImageClass? = { fileURL in
+        let asset = AVAsset(url: fileURL)
+        let assetImgGenerate = AVAssetImageGenerator(asset: asset)
+        assetImgGenerate.appliesPreferredTrackTransform = true
+        let time = CMTimeMake(asset.duration.value / 3, asset.duration.timescale)
+        if let cgImage = try? assetImgGenerate.copyCGImage(at: time, actualTime: nil) {
+            #if os(macOS)
+            return ImageClass(cgImage: cgImage, size: .zero)
+            #else
+            return ImageClass(cgImage: cgImage)
+            #endif
+        }
+        return nil
+    }
+    
+    /// Thumbnail generator closure for portable document files files.
+    static public var pdfThumbnail: (_ fileURL: URL) -> ImageClass? = { fileURL in
+        return LocalFileProvider.convertToImage(pdfURL: fileURL)
+    }
+    
+    /// Thumbnail generator closure for office document files.
+    /// - Note: No default implementation is avaiable
+    static public var officeThumbnail: (_ fileURL: URL) -> ImageClass? = { fileURL in
+        return nil
+    }
+    
+    /// Thumbnail generator closure for custom type of files.
+    /// - Note: No default implementation is avaiable
+    static public var customThumbnail: (_ fileURL: URL) -> ImageClass? = { fileURL in
+        return nil
+    }
+    
+    /// Properties generator closure for image files.
+    static public var imageProperties: ((_ fileURL: URL) -> (prop: [String: Any], keys: [String]))? = { fileURL in
+        var dic = [String: Any]()
+        var keys = [String]()
+        
+        func add(key: String, value: Any?) {
+            if let value = value, !((value as? String)?.isEmpty ?? false) {
+                keys.append(key)
+                dic[key] = value
+            }
+        }
+        
+        func simplify(_ top:Int64, _ bottom:Int64) -> (newTop:Int, newBottom:Int) {
+            var x = top
+            var y = bottom
+            while (y != 0) {
+                let buffer = y
+                y = x % y
+                x = buffer
+            }
+            let hcfVal = x
+            let newTopVal = top/hcfVal
+            let newBottomVal = bottom/hcfVal
+            return(Int(newTopVal), Int(newBottomVal))
+        }
+        
+        guard let cgDataRef = CGImageSourceCreateWithURL(fileURL as CFURL, nil), let cfImageDict = CGImageSourceCopyPropertiesAtIndex(cgDataRef, 0, nil) else {
+            return (dic, keys)
+        }
+        let imageDict = cfImageDict as NSDictionary
+        let tiffDict = imageDict[kCGImagePropertyTIFFDictionary as String] as? NSDictionary ?? [:]
+        let exifDict = imageDict[kCGImagePropertyExifDictionary as String] as? NSDictionary ?? [:]
+        if let pixelWidth = imageDict.object(forKey: kCGImagePropertyPixelWidth) as? NSNumber, let pixelHeight = imageDict.object(forKey: kCGImagePropertyPixelHeight) as? NSNumber {
+            add(key: "Dimensions", value: "\(pixelWidth)x\(pixelHeight)")
+        }
+        
+        add(key: "DPI", value: imageDict[kCGImagePropertyDPIWidth as String])
+        add(key: "Device make", value: tiffDict[kCGImagePropertyTIFFMake as String])
+        add(key: "Device model", value: tiffDict[kCGImagePropertyTIFFModel as String])
+        add(key: "Lens model", value: exifDict[kCGImagePropertyExifLensModel as String])
+        add(key: "Artist", value: tiffDict[kCGImagePropertyTIFFArtist as String] as? String)
+        add(key: "Copyright", value: tiffDict[kCGImagePropertyTIFFCopyright as String] as? String)
+        add(key: "Date taken", value: tiffDict[kCGImagePropertyTIFFDateTime as String] as? String)
+        
+        if let latitude = tiffDict[kCGImagePropertyGPSLatitude as String] as? NSNumber, let longitude = tiffDict[kCGImagePropertyGPSLongitude as String] as? NSNumber {
+            add(key: "Location", value: "\(latitude), \(longitude)")
+        }
+        add(key: "Altitude", value: tiffDict[kCGImagePropertyGPSAltitude as String] as? NSNumber)
+        add(key: "Area", value: tiffDict[kCGImagePropertyGPSAreaInformation as String])
+        
+        add(key: "Color space", value: imageDict[kCGImagePropertyColorModel as String])
+        add(key: "Focal length", value: exifDict[kCGImagePropertyExifFocalLength as String])
+        add(key: "F number", value: exifDict[kCGImagePropertyExifFNumber as String])
+        add(key: "Exposure program", value: exifDict[kCGImagePropertyExifExposureProgram as String])
+        
+        if let exp = exifDict[kCGImagePropertyExifExposureTime as String] as? NSNumber {
+            let expfrac = simplify(Int64(exp.doubleValue * 1_163_962_800_000), 1_163_962_800_000)
+            add(key: "Exposure time", value: "\(expfrac.newTop)/\(expfrac.newBottom)")
+        }
+        add(key: "ISO speed", value: (exifDict[kCGImagePropertyExifISOSpeedRatings as String] as? [NSNumber])?.first)
+        return (dic, keys)
+    }
+    
+    /// Properties generator closure for audio and music files.
+    static var audioProperties: ((_ fileURL: URL) -> (prop: [String: Any], keys: [String]))? = { fileURL in
+        var dic = [String: Any]()
+        var keys = [String]()
+        
+        func add(key: String, value: Any?) {
+            if let value = value {
+                keys.append(key)
+                dic[key] = value
+            }
+        }
+        
+        func makeDescription(_ key: String?) -> String? {
+            guard let key = key else {
+                return nil
+            }
+            guard let regex = try? NSRegularExpression(pattern: "([a-z])([A-Z])" , options: []) else {
+                return nil
+            }
+            let newKey = regex.stringByReplacingMatches(in: key, options: [], range: NSRange(location: 0, length: (key as NSString).length) , withTemplate: "$1 $2")
+            return newKey.capitalized
+        }
+        
+        guard FileManager.default.fileExists(atPath: fileURL.path) else {
+            return (dic, keys)
+        }
+        let playerItem = AVPlayerItem(url: fileURL)
+        let metadataList = playerItem.asset.commonMetadata
+        for item in metadataList {
+            #if swift(>=4.0)
+                let commonKey = item.commonKey?.rawValue
+            #else
+                let commonKey = item.commonKey
+            #endif
+            if let description = makeDescription(commonKey) {
+                if let value = item.stringValue {
+                    keys.append(description)
+                    dic[description] = value
+                }
+            }
+        }
+        if let ap = try? AVAudioPlayer(contentsOf: fileURL) {
+            add(key: "Duration", value: ap.duration.formatshort)
+            add(key: "Bitrate", value: ap.settings[AVSampleRateKey] as? Int)
+        }
+        return (dic, keys)
+    }
+    
+    /// Properties generator closure for video files.
+    static public var videoProperties: ((_ fileURL: URL) -> (prop: [String: Any], keys: [String]))? = { fileURL in
+        var dic = [String: Any]()
+        var keys = [String]()
+        
+        func add(key: String, value: Any?) {
+            if let value = value {
+                keys.append(key)
+                dic[key] = value
+            }
+        }
+        
+        if let audioprops = LocalFileInformationGenerator.audioProperties?(fileURL) {
+            dic = audioprops.prop
+            keys = audioprops.keys
+            dic.removeValue(forKey: "Duration")
+            if let index = keys.index(of: "Duration") {
+                keys.remove(at: index)
+            }
+        }
+        let asset = AVURLAsset(url: fileURL, options: nil)
+        #if swift(>=4.0)
+        let videoTracks = asset.tracks(withMediaType: AVMediaType.video)
+        #else
+        let videoTracks = asset.tracks(withMediaType: AVMediaTypeVideo)
+        #endif
+        if let videoTrack = videoTracks.first {
+            var bitrate: Float = 0
+            let width = Int(videoTrack.naturalSize.width)
+            let height = Int(videoTrack.naturalSize.height)
+            add(key: "Dimensions", value: "\(width)x\(height)")
+            var duration: Int64 = 0
+            for track in videoTracks {
+                duration += track.timeRange.duration.timescale > 0 ? track.timeRange.duration.value / Int64(track.timeRange.duration.timescale) : 0
+                bitrate += track.estimatedDataRate
+            }
+            add(key: "Duration", value: TimeInterval(duration).formatshort)
+            add(key: "Video Bitrate", value: "\(Int(ceil(bitrate / 1000))) kbps")
+        }
+        #if swift(>=4.0)
+        let audioTracks = asset.tracks(withMediaType: AVMediaType.audio)
+        #else
+        let audioTracks = asset.tracks(withMediaType: AVMediaTypeAudio)
+        #endif
+        // dic["Audio channels"] = audioTracks.count
+        var bitrate: Float = 0
+        for track in audioTracks {
+            bitrate += track.estimatedDataRate
+        }
+        add(key: "Audio Bitrate", value: "\(Int(ceil(bitrate / 1000))) kbps")
+        return (dic, keys)
+    }
+    
+    /// Properties generator closure for protable documents files.
+    static public var pdfProperties: ((_ fileURL: URL) -> (prop: [String: Any], keys: [String]))? = { fileURL in
+        var dic = [String: Any]()
+        var keys = [String]()
+        
+        func add(key: String, value: Any?) {
+            if let value = value, !((value as? String)?.isEmpty ?? false) {
+                keys.append(key)
+                dic[key] = value
+            }
+        }
+        
+        func getKey(_ key: String, from dict: CGPDFDictionaryRef) -> String? {
+            var cfStrValue: CGPDFStringRef?
+            if (CGPDFDictionaryGetString(dict, key, &cfStrValue)), let value = cfStrValue.flatMap({ CGPDFStringCopyTextString($0) }) {
+                return value as String
+            }
+            var cfArrayValue: CGPDFArrayRef?
+            if (CGPDFDictionaryGetArray(dict, key, &cfArrayValue)), let cfArray = cfArrayValue {
+                var array = [String]()
+                for i in 0..<CGPDFArrayGetCount(cfArray) {
+                    var cfItemValue: CGPDFStringRef?
+                    if CGPDFArrayGetString(cfArray, i, &cfItemValue), let item = cfItemValue.flatMap({ CGPDFStringCopyTextString($0) }) {
+                        array.append(item as String)
+                    }
+                }
+                return array.joined(separator: ", ")
+            }
+            return nil
+        }
+        
+        func convertDate(_ date: String?) -> Date? {
+            guard let date = date else { return nil }
+            var dateStr = date.replacingOccurrences(of: "'", with: "")
+            if dateStr.hasPrefix("D:") {
+                dateStr.characters.removeFirst(2)
+            }
+            let dateFormatter = DateFormatter()
+            dateFormatter.dateFormat = "yyyyMMddHHmmssTZ"
+            if let result = dateFormatter.date(from: dateStr) {
+                return result
+            }
+            dateFormatter.dateFormat = "yyyyMMddHHmmssZZZZZ"
+            if let result = dateFormatter.date(from: dateStr) {
+                return result
+            }
+            dateFormatter.dateFormat = "yyyyMMddHHmmssZ"
+            if let result = dateFormatter.date(from: dateStr) {
+                return result
+            }
+            dateFormatter.dateFormat = "yyyyMMddHHmmss"
+            if let result = dateFormatter.date(from: dateStr) {
+                return result
+            }
+            return nil
+        }
+        
+        guard let provider = CGDataProvider(url: fileURL as CFURL), let reference = CGPDFDocument(provider), let dict = reference.info else {
+            return (dic, keys)
+        }
+        add(key: "Title", value: getKey("Title", from: dict))
+        add(key: "Author", value: getKey("Author", from: dict))
+        add(key: "Subject", value: getKey("Subject", from: dict))
+        add(key: "Producer", value: getKey("Producer", from: dict))
+        add(key: "Keywords", value: getKey("Keywords", from: dict))
+        var majorVersion: Int32 = 0
+        var minorVersion: Int32 = 0
+        reference.getVersion(majorVersion: &majorVersion, minorVersion: &minorVersion)
+        if majorVersion > 0 {
+            add(key: "Version", value:  String(majorVersion) + "." + String(minorVersion))
+        }
+        add(key: "Pages", value: reference.numberOfPages)
+        
+        if reference.numberOfPages > 0, let pageRef = reference.page(at: 1) {
+            let size = pageRef.getBoxRect(CGPDFBox.mediaBox).size
+            add(key: "Resolution", value: "\(Int(size.width))x\(Int(size.height))")
+        }
+        add(key: "Content creator", value: getKey("Creator", from: dict))
+        add(key: "Creation date", value: convertDate(getKey("CreationDate", from: dict)))
+        add(key: "Modified date", value: convertDate(getKey("ModDate", from: dict)))
+        add(key: "Security", value: reference.isEncrypted)
+        add(key: "Allows printing", value: reference.allowsPrinting)
+        add(key: "Allows copying", value: reference.allowsCopying)
+        return (dic, keys)
+    }
+    
+    /// Properties generator closure for video files.
+    /// - Note: No default implementation is avaiable
+    static public var archiveProperties: ((_ fileURL: URL) -> (prop: [String: Any], keys: [String]))? = nil
+    
+    /// Properties generator closure for office doument files.
+    /// - Note: No default implementation is avaiable
+    static public var officeProperties: ((_ fileURL: URL) -> (prop: [String: Any], keys: [String]))? = nil
+    
+    /// Properties generator closure for custom type of files.
+    /// - Note: No default implementation is avaiable
+    static public var customProperties: ((_ fileURL: URL) -> (prop: [String: Any], keys: [String]))? = nil
+}
+
+fileprivate func ~=<T : Equatable>(array: [T], value: T) -> Bool {
+    return array.contains(value)
+}
@@ -0,0 +1,887 @@
+//
+//  FTPFileProvider.swift
+//  FileProvider
+//
+//  Created by Amir Abbas Mousavian.
+//  Copyright © 2017 Mousavian. Distributed under MIT license.
+//
+
+import Foundation
+
+/**
+ Allows accessing to FTP files and directories. This provider doesn't cache or save files internally.
+ It's a complete reimplementation and doesn't use CFNetwork deprecated API.
+ */
+open class FTPFileProvider: FileProviderBasicRemote {
+    open class var type: String { return "FTP" }
+    open let baseURL: URL?
+    open var currentPath: String
+    
+    open var dispatch_queue: DispatchQueue
+    open var operation_queue: OperationQueue {
+        willSet {
+            assert(_session == nil, "It's not effective to change dispatch_queue property after session is initialized.")
+        }
+    }
+    
+    open weak var delegate: FileProviderDelegate?
+    open var credential: URLCredential? {
+        didSet {
+            sessionDelegate?.credential = self.credential
+        }
+    }
+    open private(set) var cache: URLCache?
+    public var useCache: Bool
+    public var validatingCache: Bool
+    
+    /// Determine either FTP session is in passive or active mode.
+    public let passiveMode: Bool
+    
+    /// Force to use URLSessionDownloadTask/URLSessionDataTask when possible
+    public var useAppleImplementation = true
+    
+    fileprivate var _session: URLSession?
+    internal var sessionDelegate: SessionDelegate?
+    public var session: URLSession {
+        get {
+            if _session == nil {
+                self.sessionDelegate = SessionDelegate(fileProvider: self)
+                let config = URLSessionConfiguration.default
+                config.urlCache = cache
+                config.requestCachePolicy = .returnCacheDataElseLoad
+                _session = URLSession(configuration: config, delegate: sessionDelegate as URLSessionDelegate?, delegateQueue: self.operation_queue)
+                _session?.sessionDescription = UUID().uuidString
+                initEmptySessionHandler(_session!.sessionDescription!)
+            }
+            return _session!
+        }
+        
+        set {
+            assert(newValue.delegate is SessionDelegate, "session instances should have a SessionDelegate instance as delegate.")
+            _session = newValue
+            if session.sessionDescription?.isEmpty ?? true {
+                _session?.sessionDescription = UUID().uuidString
+            }
+            self.sessionDelegate = newValue.delegate as? SessionDelegate
+            initEmptySessionHandler(_session!.sessionDescription!)
+        }
+    }
+    
+    /**
+     Initializer for FTP provider with given username and password.
+     
+     - Note: `passive` value should be set according to server settings and firewall presence.
+     
+     - Parameter baseURL: a url with `ftp://hostaddress/` format.
+     - Parameter passive: FTP server data connection, `true` means passive connection (data connection created by client)
+         and `false` means active connection (data connection created by server). Default is `true` (passive mode).
+     - Parameter credential: a `URLCredential` object contains user and password.
+     - Parameter cache: A URLCache to cache downloaded files and contents. (unimplemented for FTP and should be nil)
+     */
+    public init? (baseURL: URL, passive: Bool = true, credential: URLCredential? = nil, cache: URLCache? = nil) {
+        guard (baseURL.scheme ?? "ftp").lowercased().hasPrefix("ftp") else { return nil }
+        guard baseURL.host != nil else { return nil }
+        var urlComponents = URLComponents(url: baseURL, resolvingAgainstBaseURL: true)!
+        let defaultPort: Int = baseURL.scheme == "ftps" ? 990 : 21
+        urlComponents.port = urlComponents.port ?? defaultPort
+        urlComponents.scheme = urlComponents.scheme ?? "ftp"
+        
+        self.baseURL =  (urlComponents.url!.path.hasSuffix("/") ? urlComponents.url! : urlComponents.url!.appendingPathComponent("")).absoluteURL
+        self.passiveMode = passive
+        self.currentPath = ""
+        self.useCache = false
+        self.validatingCache = true
+        self.cache = cache
+        self.credential = credential
+        
+        #if swift(>=3.1)
+        let queueLabel = "FileProvider.\(Swift.type(of: self).type)"
+        #else
+        let queueLabel = "FileProvider.\(type(of: self).type)"
+        #endif
+        dispatch_queue = DispatchQueue(label: queueLabel, attributes: .concurrent)
+        operation_queue = OperationQueue()
+        operation_queue.name = "\(queueLabel).Operation"
+    }
+    
+    public required convenience init?(coder aDecoder: NSCoder) {
+        guard let baseURL = aDecoder.decodeObject(forKey: "baseURL") as? URL else { return nil }
+        self.init(baseURL: baseURL, passive: aDecoder.decodeBool(forKey: "passiveMode"), credential: aDecoder.decodeObject(forKey: "credential") as? URLCredential)
+        self.currentPath     = aDecoder.decodeObject(forKey: "currentPath") as? String ?? ""
+        self.useCache        = aDecoder.decodeBool(forKey: "useCache")
+        self.validatingCache = aDecoder.decodeBool(forKey: "validatingCache")
+        self.useAppleImplementation = aDecoder.decodeBool(forKey: "useAppleImplementation")
+    }
+    
+    public func encode(with aCoder: NSCoder) {
+        aCoder.encode(self.baseURL, forKey: "baseURL")
+        aCoder.encode(self.credential, forKey: "credential")
+        aCoder.encode(self.currentPath, forKey: "currentPath")
+        aCoder.encode(self.useCache, forKey: "useCache")
+        aCoder.encode(self.validatingCache, forKey: "validatingCache")
+        aCoder.encode(self.useAppleImplementation, forKey: "useAppleImplementation")
+        aCoder.encode(self.passiveMode, forKey: "passiveMode")
+    }
+    
+    public static var supportsSecureCoding: Bool {
+        return true
+    }
+    
+    open func copy(with zone: NSZone? = nil) -> Any {
+        let copy = FTPFileProvider(baseURL: self.baseURL!, credential: self.credential, cache: self.cache)!
+        copy.currentPath = self.currentPath
+        copy.delegate = self.delegate
+        copy.fileOperationDelegate = self.fileOperationDelegate
+        copy.useCache = self.useCache
+        copy.validatingCache = self.validatingCache
+        copy.useAppleImplementation = self.useAppleImplementation
+        return copy
+    }
+    
+    deinit {
+        if let sessionuuid = _session?.sessionDescription {
+            removeSessionHandler(for: sessionuuid)
+        }
+        
+        if fileProviderCancelTasksOnInvalidating {
+            _session?.invalidateAndCancel()
+        } else {
+            _session?.finishTasksAndInvalidate()
+        }
+    }
+    
+    internal var serverSupportsRFC3659: Bool = true
+    
+    open func contentsOfDirectory(path: String, completionHandler: @escaping (([FileObject], Error?) -> Void)) {
+        self.contentsOfDirectory(path: path, rfc3659enabled: serverSupportsRFC3659, completionHandler: completionHandler)
+    }
+    
+    /**
+     Returns an Array of `FileObject`s identifying the the directory entries via asynchronous completion handler.
+     
+     If the directory contains no entries or an error is occured, this method will return the empty array.
+     
+     - Parameter path: path to target directory. If empty, `currentPath` value will be used.
+     - Parameter rfc3659enabled: uses MLST command instead of old LIST to get files attributes, default is `true`.
+     - Parameter completionHandler: a closure with result of directory entries or error.
+         `contents`: An array of `FileObject` identifying the the directory entries.
+         `error`: Error returned by system.
+     */
+    open func contentsOfDirectory(path apath: String, rfc3659enabled: Bool , completionHandler: @escaping ((_ contents: [FileObject], _ error: Error?) -> Void)) {
+        let path = ftpPath(apath)
+        
+        let task = session.fpstreamTask(withHostName: baseURL!.host!, port: baseURL!.port!)
+        self.ftpLogin(task) { (error) in
+            if let error = error {
+                self.dispatch_queue.async {
+                    completionHandler([], error)
+                }
+                return
+            }
+            
+            self.ftpList(task, of: self.ftpPath(path), useMLST: rfc3659enabled, completionHandler: { (contents, error) in
+                defer {
+                    self.ftpQuit(task)
+                }
+                if let error = error {
+                    if ((error as NSError).domain == URLError.errorDomain && (error as NSError).code == URLError.unsupportedURL.rawValue) {
+                        self.contentsOfDirectory(path: path, rfc3659enabled: false, completionHandler: completionHandler)
+                        return
+                    }
+                    
+                    self.dispatch_queue.async {
+                        completionHandler([], error)
+                    }
+                    return
+                }
+                
+                
+                let files: [FileObject] = contents.flatMap {
+                    rfc3659enabled ? self.parseMLST($0, in: path) : self.parseUnixList($0, in: path)
+                }
+                
+                self.dispatch_queue.async {
+                    completionHandler(files, nil)
+                }
+            })
+        }
+    }
+    
+    open func attributesOfItem(path: String, completionHandler: @escaping ((FileObject?, Error?) -> Void)) {
+        self.attributesOfItem(path: path, rfc3659enabled: serverSupportsRFC3659, completionHandler: completionHandler)
+    }
+    
+    /**
+     Returns a `FileObject` containing the attributes of the item (file, directory, symlink, etc.) at the path in question via asynchronous completion handler.
+     
+     If the directory contains no entries or an error is occured, this method will return the empty `FileObject`.
+     
+     - Parameter path: path to target directory. If empty, `currentPath` value will be used.
+     - Parameter rfc3659enabled: uses MLST command instead of old LIST to get files attributes, default is true.
+     - Parameter completionHandler: a closure with result of directory entries or error.
+         `attributes`: A `FileObject` containing the attributes of the item.
+         `error`: Error returned by system.
+     */
+    open func attributesOfItem(path apath: String, rfc3659enabled: Bool, completionHandler: @escaping ((_ attributes: FileObject?, _ error: Error?) -> Void)) {
+        let path = ftpPath(apath)
+        
+        let task = session.fpstreamTask(withHostName: baseURL!.host!, port: baseURL!.port!)
+        self.ftpLogin(task) { (error) in
+            if let error = error {
+                self.dispatch_queue.async {
+                    completionHandler(nil, error)
+                }
+                return
+            }
+            
+            let command = rfc3659enabled ? "MLST \(path)" : "LIST \(path)"
+            self.execute(command: command, on: task, completionHandler: { (response, error) in
+                defer {
+                    self.ftpQuit(task)
+                }
+                if let error = error {
+                    self.dispatch_queue.async {
+                        completionHandler(nil, error)
+                    }
+                    return
+                }
+                
+                guard let response = response, response.hasPrefix("250") || (response.hasPrefix("50") && rfc3659enabled) else {
+                    self.dispatch_queue.async {
+                        completionHandler(nil, self.throwError(path, code: URLError.badServerResponse))
+                    }
+                    return
+                }
+                
+                if response.hasPrefix("500") {
+                    self.serverSupportsRFC3659 = false
+                    self.attributesOfItem(path: path, rfc3659enabled: false, completionHandler: completionHandler)
+                }
+                
+                let lines = response.components(separatedBy: "\n").flatMap { $0.isEmpty ? nil : $0.trimmingCharacters(in: .whitespacesAndNewlines) }
+                guard lines.count > 2 else {
+                    self.dispatch_queue.async {
+                        completionHandler(nil, self.throwError(path, code: URLError.badServerResponse))
+                    }
+                    return
+                }
+                let file = rfc3659enabled ? self.parseMLST(lines[1], in: path) : self.parseUnixList(lines[1], in: path)
+                self.dispatch_queue.async {
+                    completionHandler(file, nil)
+                }
+            })
+        }
+    }
+    
+    open func storageProperties(completionHandler: @escaping ((_ total: Int64, _ used: Int64) -> Void)) {
+        dispatch_queue.async {
+            completionHandler(-1, 0)
+        }
+    }
+    
+    open func searchFiles(path: String, recursive: Bool, query: NSPredicate, foundItemHandler: ((FileObject) -> Void)?, completionHandler: @escaping ((_ files: [FileObject], _ error: Error?) -> Void)) -> Progress? {
+        let progress = Progress(parent: nil, userInfo: nil)
+        _ = self.recursiveList(path: path, useMLST: true, foundItemsHandler: { items in
+            if let foundItemHandler = foundItemHandler {
+                for item in items where query.evaluate(with: item.mapPredicate()) {
+                    foundItemHandler(item)
+                }
+                progress.totalUnitCount = Int64(items.count)
+            }
+        }, completionHandler: {files, error in
+            if let error = error {
+                completionHandler([], error)
+                return
+            }
+            
+            let foundFiles = files.filter { query.evaluate(with: $0.mapPredicate()) }
+            completionHandler(foundFiles, nil)
+        })
+        return progress
+    }
+    
+    public func url(of path: String?) -> URL {
+        let path = (path ?? self.currentPath).trimmingCharacters(in: CharacterSet(charactersIn: "/ ")).addingPercentEncoding(withAllowedCharacters: .urlPathAllowed) ?? (path ?? self.currentPath)
+        
+        var baseUrlComponent = URLComponents(url: self.baseURL!, resolvingAgainstBaseURL: true)
+        baseUrlComponent?.user = credential?.user
+        baseUrlComponent?.password = credential?.password
+        return URL(string: path, relativeTo: baseUrlComponent?.url ?? baseURL) ?? baseUrlComponent?.url ?? baseURL!
+    }
+    
+    public func relativePathOf(url: URL) -> String {
+        // check if url derieved from current base url
+        let relativePath = url.relativePath
+        if !relativePath.isEmpty, url.baseURL == self.baseURL {
+            return (relativePath.removingPercentEncoding ?? relativePath).replacingOccurrences(of: "/", with: "", options: .anchored)
+        }
+        
+        if !relativePath.isEmpty, self.baseURL == self.url(of: "/") {
+            return (relativePath.removingPercentEncoding ?? relativePath).replacingOccurrences(of: "/", with: "", options: .anchored)
+        }
+        
+        return relativePath.replacingOccurrences(of: "/", with: "", options: .anchored)
+    }
+    
+    open func isReachable(completionHandler: @escaping (Bool) -> Void) {
+        self.attributesOfItem(path: "/") { (file, error) in
+            completionHandler(file != nil)
+        }
+    }
+    
+    open weak var fileOperationDelegate: FileOperationDelegate?
+}
+
+extension FTPFileProvider: FileProviderOperations {
+    open func create(folder folderName: String, at atPath: String, completionHandler: SimpleCompletionHandler) -> Progress? {
+        let path = (atPath as NSString).appendingPathComponent(folderName) + "/"
+        return doOperation(.create(path: path), completionHandler: completionHandler)
+    }
+    
+    open func moveItem(path: String, to toPath: String, overwrite: Bool, completionHandler: SimpleCompletionHandler) -> Progress? {
+        return doOperation(.move(source: path, destination: toPath), completionHandler: completionHandler)
+    }
+    
+    open func copyItem(path: String, to toPath: String, overwrite: Bool, completionHandler: SimpleCompletionHandler) -> Progress? {
+        return doOperation(.copy(source: path, destination: toPath), completionHandler: completionHandler)
+    }
+    
+    open func removeItem(path: String, completionHandler: SimpleCompletionHandler) -> Progress? {
+        return doOperation(.remove(path: path), completionHandler: completionHandler)
+    }
+    
+    fileprivate func doOperation(_ opType: FileOperationType, completionHandler: SimpleCompletionHandler) -> Progress? {
+        guard fileOperationDelegate?.fileProvider(self, shouldDoOperation: opType) ?? true == true else {
+            return nil
+        }
+        let sourcePath = opType.source
+        let destPath = opType.destination
+        
+        let command: String
+        switch opType {
+        case .create:
+            command = "MKD \(ftpPath(sourcePath))"
+        case .copy:
+            command = "SITE CPFR \(ftpPath(sourcePath))\r\nSITE CPTO \(ftpPath(destPath!))"
+        case .move:
+            command = "RNFR \(ftpPath(sourcePath))\r\nRNTO \(ftpPath(destPath!))"
+        case .remove:
+            command = "DELE \(ftpPath(sourcePath))"
+        case .link:
+            command = "SITE SYMLINK \(ftpPath(sourcePath)) \(ftpPath(destPath!))"
+        default: // modify, fetch
+            return nil
+        }
+        let progress = Progress(totalUnitCount: 1)
+        progress.setUserInfoObject(opType, forKey: .fileProvderOperationTypeKey)
+        progress.kind = .file
+        progress.setUserInfoObject(Progress.FileOperationKind.downloading, forKey: .fileOperationKindKey)
+        
+        let task = session.fpstreamTask(withHostName: baseURL!.host!, port: baseURL!.port!)
+        self.ftpLogin(task) { (error) in
+            if let error = error {
+                self.dispatch_queue.async {
+                    completionHandler?(error)
+                    self.delegateNotify(opType, error: error)
+                }
+                return
+            }
+            
+            self.execute(command: command, on: task, completionHandler: { (response, error) in
+                if let error = error {
+                    self.dispatch_queue.async {
+                        completionHandler?(error)
+                        self.delegateNotify(opType, error: error)
+                    }
+                    return
+                }
+                
+                guard let response = response else {
+                    self.dispatch_queue.async {
+                        completionHandler?(error)
+                        self.delegateNotify(opType, error: self.throwError(sourcePath, code: URLError.badServerResponse))
+                    }
+                    return
+                }
+                
+                let codes: [Int] = response.components(separatedBy: .newlines).flatMap({ $0.isEmpty ? nil : $0})
+                .flatMap {
+                    let code = $0.components(separatedBy: .whitespaces).flatMap({ $0.isEmpty ? nil : $0}).first
+                    return code != nil ? Int(code!) : nil
+                }
+                
+                if codes.filter({ (450..<560).contains($0) }).count > 0 {
+                    let errorCode: URLError.Code
+                    switch opType {
+                    case .create:
+                        errorCode = URLError.cannotCreateFile
+                    case .modify:
+                        errorCode = URLError.cannotWriteToFile
+                    case .copy:
+                        self.fallbackCopy(opType, progress: progress, completionHandler: completionHandler)
+                        return
+                    case .move:
+                        errorCode = URLError.cannotMoveFile
+                    case .remove:
+                        self.fallbackRemove(opType, progress: progress, on: task, completionHandler: completionHandler)
+                        return
+                    case .link:
+                        errorCode = URLError.cannotWriteToFile
+                    default:
+                        errorCode = URLError.cannotOpenFile
+                    }
+                    let error = self.throwError(sourcePath, code: errorCode)
+                    progress.cancel()
+                    self.dispatch_queue.async {
+                        completionHandler?(error)
+                    }
+                    self.delegateNotify(opType, error: error)
+                    return
+                }
+                
+                progress.completedUnitCount = progress.totalUnitCount
+                self.dispatch_queue.async {
+                    completionHandler?(nil)
+                }
+                self.delegateNotify(opType, error: nil)
+            })
+        }
+        
+        progress.cancellationHandler = { [weak task] in
+            task?.cancel()
+        }
+        progress.setUserInfoObject(Date(), forKey: .startingTimeKey)
+        return progress
+    }
+    
+    private func fallbackCopy(_ opType: FileOperationType, progress: Progress, completionHandler: SimpleCompletionHandler) {
+        let sourcePath = opType.source
+        guard let destPath = opType.destination else { return }
+        
+        let localURL = URL(fileURLWithPath: NSTemporaryDirectory()).appendingPathComponent(UUID().uuidString).appendingPathExtension("tmp")
+        
+        progress.becomeCurrent(withPendingUnitCount: 1)
+        _ = self.copyItem(path: sourcePath, toLocalURL: localURL) { (error) in
+            if let error = error {
+                self.dispatch_queue.async {
+                    completionHandler?(error)
+                    self.delegateNotify(opType, error: error)
+                }
+                return
+            }
+            
+            progress.becomeCurrent(withPendingUnitCount: 1)
+            _ = self.copyItem(localFile: localURL, to: destPath) { error in
+                completionHandler?(nil)
+                self.delegateNotify(opType, error: nil)
+            }
+            progress.resignCurrent()
+        }
+        progress.resignCurrent()
+        return
+    }
+    
+    private func fallbackRemove(_ opType: FileOperationType, progress: Progress, on task: FileProviderStreamTask, completionHandler: SimpleCompletionHandler) {
+        let sourcePath = opType.source
+        
+        self.execute(command: "SITE RMDIR \(ftpPath(sourcePath))", on: task) { (response, error) in
+            if let error = error {
+                progress.cancel()
+                self.dispatch_queue.async {
+                    completionHandler?(error)
+                }
+                self.delegateNotify(opType, error: error)
+                return
+            }
+            
+            guard let response = response else {
+                progress.cancel()
+                let error = self.throwError(sourcePath, code: URLError.badServerResponse)
+                self.dispatch_queue.async {
+                    completionHandler?(error)
+                }
+                self.delegateNotify(opType, error: error)
+                return
+            }
+            
+            if response.hasPrefix("50") {
+                self.fallbackRecursiveRemove(opType, progress: progress, on: task, completionHandler: completionHandler)
+                return
+            }
+            
+            var error: Error?
+            if !response.hasPrefix("2") {
+                error = self.throwError(sourcePath, code: URLError.cannotRemoveFile)
+            }
+            self.dispatch_queue.async {
+                completionHandler?(error)
+            }
+            self.delegateNotify(opType, error: error)
+        }
+    }
+    
+    private func fallbackRecursiveRemove(_ opType: FileOperationType, progress: Progress, on task: FileProviderStreamTask, completionHandler: SimpleCompletionHandler) {
+        let sourcePath = opType.source
+        
+        _ = self.recursiveList(path: sourcePath, useMLST: true, completionHandler: { (contents, error) in
+            if let error = error {
+                self.dispatch_queue.async {
+                    completionHandler?(error)
+                    self.delegateNotify(opType, error: error)
+                }
+                return
+            }
+            
+            let recursiveProgress = Progress(parent: progress, userInfo: nil)
+            recursiveProgress.totalUnitCount = Int64(contents.count)
+            let sortedContents = contents.sorted(by: {
+                $0.path.localizedStandardCompare($1.path) == .orderedDescending
+            })
+            var command = ""
+            for file in sortedContents {
+                command += (file.isDirectory ? "RMD \(self.ftpPath(file.path))" : "DELE \(self.ftpPath(file.path))") + "\r\n"
+            }
+            command += "RMD \(self.ftpPath(sourcePath))"
+            
+            self.execute(command: command, on: task, completionHandler: { (response, error) in
+                recursiveProgress.completedUnitCount += 1
+                self.dispatch_queue.async {
+                    completionHandler?(error)
+                    self.delegateNotify(opType, error: error)
+                }
+                // TODO: Digest response
+            })
+        })
+    }
+    
+    open func copyItem(localFile: URL, to toPath: String, overwrite: Bool, completionHandler: SimpleCompletionHandler) -> Progress? {
+        // check file is not a folder
+        guard (try? localFile.resourceValues(forKeys: [.fileResourceTypeKey]))?.fileResourceType ?? .unknown == .regular else {
+            dispatch_queue.async {
+                completionHandler?(self.throwError(localFile.path, code: URLError.fileIsDirectory))
+            }
+            return nil
+        }
+        
+        let opType = FileOperationType.copy(source: localFile.absoluteString, destination: toPath)
+        guard fileOperationDelegate?.fileProvider(self, shouldDoOperation: opType) ?? true == true else {
+            return nil
+        }
+        
+        let progress = Progress(totalUnitCount: 0)
+        progress.setUserInfoObject(opType, forKey: .fileProvderOperationTypeKey)
+        progress.kind = .file
+        progress.setUserInfoObject(Progress.FileOperationKind.downloading, forKey: .fileOperationKindKey)
+        
+        let task = session.fpstreamTask(withHostName: baseURL!.host!, port: baseURL!.port!)
+        self.ftpLogin(task) { (error) in
+            if let error = error {
+                self.dispatch_queue.async {
+                    completionHandler?(error)
+                    self.delegateNotify(opType, error: error)
+                }
+                return
+            }
+            
+            self.ftpStore(task, filePath: self.ftpPath(toPath), fromData: nil, fromFile: localFile, onTask: { task in
+                weak var weakTask = task
+                progress.cancellationHandler = {
+                    weakTask?.cancel()
+                }
+                progress.setUserInfoObject(Date(), forKey: .startingTimeKey)
+            }, onProgress: { bytesSent, totalSent, expectedBytes in
+                progress.completedUnitCount = totalSent
+                DispatchQueue.main.async {
+                    self.delegate?.fileproviderProgress(self, operation: opType, progress: Float(progress.fractionCompleted))
+                }
+            }, completionHandler: { (error) in
+                if error != nil {
+                    progress.cancel()
+                }
+                self.ftpQuit(task)
+                self.dispatch_queue.async {
+                    completionHandler?(error)
+                    self.delegateNotify(opType, error: error)
+                }
+            })
+        }
+        
+        return progress
+    }
+    
+    open func copyItem(path: String, toLocalURL destURL: URL, completionHandler: SimpleCompletionHandler) -> Progress? {
+        let opType = FileOperationType.copy(source: path, destination: destURL.absoluteString)
+        guard fileOperationDelegate?.fileProvider(self, shouldDoOperation: opType) ?? true == true else {
+            return nil
+        }
+        var progress = Progress(totalUnitCount: 0)
+        progress.setUserInfoObject(opType, forKey: .fileProvderOperationTypeKey)
+        progress.kind = .file
+        progress.setUserInfoObject(Progress.FileOperationKind.downloading, forKey: .fileOperationKindKey)
+        
+        if self.useAppleImplementation {
+            self.attributesOfItem(path: path, completionHandler: { (file, error) in
+                if let error = error {
+                    self.dispatch_queue.async {
+                        completionHandler?(error)
+                        self.delegateNotify(opType, error: error)
+                    }
+                    return
+                }
+                
+                if file?.isDirectory ?? false {
+                    self.dispatch_queue.async {
+                        let error = self.throwError(path, code: URLError.fileIsDirectory)
+                        completionHandler?(error)
+                        self.delegateNotify(opType, error: error)
+                    }
+                    return
+                }
+                
+                progress.totalUnitCount = file?.size ?? 0
+                
+                let task = self.session.downloadTask(with: self.url(of: path))
+                completionHandlersForTasks[self.session.sessionDescription!]?[task.taskIdentifier] = completionHandler
+                downloadCompletionHandlersForTasks[self.session.sessionDescription!]?[task.taskIdentifier] = { tempURL in
+                    do {
+                        try FileManager.default.moveItem(at: tempURL, to: destURL)
+                        completionHandler?(nil)
+                    } catch let e {
+                        completionHandler?(e)
+                    }
+                }
+                task.taskDescription = opType.json
+                task.addObserver(self.sessionDelegate!, forKeyPath: #keyPath(URLSessionTask.countOfBytesReceived), options: .new, context: &progress)
+                task.addObserver(self.sessionDelegate!, forKeyPath: #keyPath(URLSessionTask.countOfBytesExpectedToReceive), options: .new, context: &progress)
+                progress.cancellationHandler = { [weak task] in
+                    task?.cancel()
+                }
+                progress.setUserInfoObject(Date(), forKey: .startingTimeKey)
+                task.resume()
+            })
+        } else {
+            let task = session.fpstreamTask(withHostName: baseURL!.host!, port: baseURL!.port!)
+            self.ftpLogin(task) { (error) in
+                if let error = error {
+                    self.dispatch_queue.async {
+                        completionHandler?(error)
+                    }
+                    return
+                }
+                
+                self.ftpRetrieveFile(task, filePath: self.ftpPath(path), onTask: { task in
+                    weak var weakTask = task
+                    progress.cancellationHandler = {
+                        weakTask?.cancel()
+                    }
+                    progress.setUserInfoObject(Date(), forKey: .startingTimeKey)
+                }, onProgress: { recevied, totalReceived, totalSize in
+                    progress.totalUnitCount = totalSize
+                    progress.completedUnitCount = totalReceived
+                    DispatchQueue.main.async {
+                        self.delegate?.fileproviderProgress(self, operation: opType, progress: Float(progress.fractionCompleted))
+                    }
+                }) { (tmpurl, error) in
+                    if let error = error {
+                        progress.cancel()
+                        self.dispatch_queue.async {
+                            completionHandler?(error)
+                            self.delegateNotify(opType, error: error)
+                        }
+                        return
+                    }
+                    
+                    if let tmpurl = tmpurl {
+                        try? FileManager.default.moveItem(at: tmpurl, to: destURL)
+                        self.dispatch_queue.async {
+                            completionHandler?(nil)
+                            self.delegateNotify(opType, error: nil)
+                        }
+                    }
+                }
+            }
+        }
+        return progress
+    }
+}
+
+extension FTPFileProvider: FileProviderReadWrite {
+    open func contents(path: String, completionHandler: @escaping ((Data?, Error?) -> Void)) -> Progress? {
+        let opType = FileOperationType.fetch(path: path)
+        guard fileOperationDelegate?.fileProvider(self, shouldDoOperation: opType) ?? true == true else {
+            return nil
+        }
+        
+        if self.useAppleImplementation {
+            var progress = Progress(totalUnitCount: 0)
+            progress.setUserInfoObject(opType, forKey: .fileProvderOperationTypeKey)
+            progress.kind = .file
+            progress.setUserInfoObject(Progress.FileOperationKind.downloading, forKey: .fileOperationKindKey)
+            
+            let task = session.downloadTask(with: url(of: path))
+            completionHandlersForTasks[session.sessionDescription!]?[task.taskIdentifier] = { error in
+                if error != nil {
+                    progress.cancel()
+                }
+                completionHandler(nil, error)
+            }
+            downloadCompletionHandlersForTasks[session.sessionDescription!]?[task.taskIdentifier] = { tempURL in
+                do {
+                    let data = try Data(contentsOf: tempURL)
+                    completionHandler(data, nil)
+                } catch let e {
+                    completionHandler(nil, e)
+                }
+            }
+            task.taskDescription = opType.json
+            task.addObserver(sessionDelegate!, forKeyPath: #keyPath(URLSessionTask.countOfBytesReceived), options: .new, context: &progress)
+            task.addObserver(sessionDelegate!, forKeyPath: #keyPath(URLSessionTask.countOfBytesExpectedToReceive), options: .new, context: &progress)
+            progress.cancellationHandler = { [weak task] in
+                task?.cancel()
+            }
+            progress.setUserInfoObject(Date(), forKey: .startingTimeKey)
+            task.resume()
+            return progress
+        } else {
+            return self.contents(path: path, offset: 0, length: -1, completionHandler: completionHandler)
+        }
+    }
+    
+    open func contents(path: String, offset: Int64, length: Int, completionHandler: @escaping ((_ contents: Data?, _ error: Error?) -> Void)) -> Progress? {
+        let opType = FileOperationType.fetch(path: path)
+        if length == 0 || offset < 0 {
+            dispatch_queue.async {
+                completionHandler(Data(), nil)
+                self.delegateNotify(opType, error: nil)
+            }
+            return nil
+        }
+        let progress = Progress(totalUnitCount: 0)
+        progress.setUserInfoObject(opType, forKey: .fileProvderOperationTypeKey)
+        progress.kind = .file
+        progress.setUserInfoObject(Progress.FileOperationKind.downloading, forKey: .fileOperationKindKey)
+        
+        let task = session.fpstreamTask(withHostName: baseURL!.host!, port: baseURL!.port!)
+        self.ftpLogin(task) { (error) in
+            if let error = error {
+                self.dispatch_queue.async {
+                    completionHandler(nil, error)
+                }
+                return
+            }
+            
+            self.ftpRetrieveData(task, filePath: self.ftpPath(path), from: offset, length: length, onTask: { task in
+                weak var weakTask = task
+                progress.cancellationHandler = {
+                    weakTask?.cancel()
+                }
+                progress.setUserInfoObject(Date(), forKey: .startingTimeKey)
+            }, onProgress: { recevied, totalReceived, totalSize in
+                progress.totalUnitCount = totalSize
+                progress.completedUnitCount = totalReceived
+                DispatchQueue.main.async {
+                    self.delegate?.fileproviderProgress(self, operation: opType, progress: Float(progress.fractionCompleted))
+                }
+            }) { (data, error) in
+                if let error = error {
+                    progress.cancel()
+                    self.dispatch_queue.async {
+                        completionHandler(nil, error)
+                        self.delegateNotify(opType, error: error)
+                    }
+                    return
+                }
+                
+                if let data = data {
+                    self.dispatch_queue.async {
+                        completionHandler(data, nil)
+                        self.delegateNotify(opType, error: nil)
+                    }
+                }
+            }
+        }
+        
+        return progress
+    }
+    
+    open func writeContents(path: String, contents data: Data?, atomically: Bool, overwrite: Bool, completionHandler: SimpleCompletionHandler) -> Progress? {
+        let opType = FileOperationType.modify(path: path)
+        guard fileOperationDelegate?.fileProvider(self, shouldDoOperation: opType) ?? true == true else {
+            return nil
+        }
+        
+        let progress = Progress(totalUnitCount: Int64(data?.count ?? 0))
+        progress.setUserInfoObject(opType, forKey: .fileProvderOperationTypeKey)
+        progress.kind = .file
+        progress.setUserInfoObject(Progress.FileOperationKind.downloading, forKey: .fileOperationKindKey)
+        
+        let task = session.fpstreamTask(withHostName: baseURL!.host!, port: baseURL!.port!)
+        self.ftpLogin(task) { (error) in
+            if let error = error {
+                self.dispatch_queue.async {
+                    completionHandler?(error)
+                    self.delegateNotify(opType, error: error)
+                }
+                return
+            }
+            
+            let storeHandler = {
+                self.ftpStore(task, filePath: self.ftpPath(path), fromData: data ?? Data(), fromFile: nil, onTask: { task in
+                    weak var weakTask = task
+                    progress.cancellationHandler = {
+                        weakTask?.cancel()
+                    }
+                    progress.setUserInfoObject(Date(), forKey: .startingTimeKey)
+                }, onProgress: { bytesSent, totalSent, expectedBytes in
+                    progress.completedUnitCount = totalSent
+                    DispatchQueue.main.async {
+                        self.delegate?.fileproviderProgress(self, operation: opType, progress: Float(progress.fractionCompleted))
+                    }
+                }, completionHandler: { (error) in
+                    if error != nil {
+                        progress.cancel()
+                    }
+                    self.ftpQuit(task)
+                    self.dispatch_queue.async {
+                        completionHandler?(error)
+                        self.delegateNotify(opType, error: error)
+                    }
+                })
+            }
+            
+            if overwrite {
+                storeHandler()
+            } else {
+                self.attributesOfItem(path: path, completionHandler: { (file, erroe) in
+                    if file == nil {
+                        storeHandler()
+                    }
+                })
+            }
+        }
+        
+        return progress
+    }
+}
+
+public extension FTPFileProvider {
+    /**
+     Creates a symbolic link at the specified path that points to an item at the given path.
+     This method does not traverse symbolic links contained in destination path, making it possible
+     to create symbolic links to locations that do not yet exist.
+     Also, if the final path component is a symbolic link, that link is not followed.
+     
+     - Note: Many servers does't support this functionality.
+     
+     - Parameters:
+       - symbolicLink: The file path at which to create the new symbolic link. The last component of the path issued as the name of the link.
+       - withDestinationPath: The path that contains the item to be pointed to by the link. In other words, this is the destination of the link.
+       - completionHandler: If an error parameter was provided, a presentable `Error` will be returned.
+     */
+    public func create(symbolicLink path: String, withDestinationPath destPath: String, completionHandler: SimpleCompletionHandler) {
+        let opType = FileOperationType.link(link: path, target: destPath)
+        _=self.doOperation(opType, completionHandler: completionHandler)
+    }
+}
+
+extension FTPFileProvider: FileProvider { }
@@ -0,0 +1,965 @@
+//
+//  FTPHelper.swift
+//  FileProvider
+//
+//  Created by Amir Abbas Mousavian.
+//  Copyright © 2017 Mousavian. Distributed under MIT license.
+//
+
+import Foundation
+
+internal extension FTPFileProvider {
+    func delegateNotify(_ operation: FileOperationType, error: Error?) {
+        DispatchQueue.main.async(execute: {
+            if error == nil {
+                self.delegate?.fileproviderSucceed(self, operation: operation)
+            } else {
+                self.delegate?.fileproviderFailed(self, operation: operation)
+            }
+        })
+    }
+    
+    func readDataUntilEOF(of task: FileProviderStreamTask, minLength: Int, receivedData: Data? = nil, timeout: TimeInterval, completionHandler: @escaping (_ data: Data?, _ errror:Error?) -> Void) {
+        task.readData(ofMinLength: minLength, maxLength: 65535, timeout: timeout) { (data, eof, error) in
+            if let error = error {
+                completionHandler(nil, error)
+                return
+            }
+            
+            var receivedData = receivedData
+            if let data = data {
+                if receivedData != nil {
+                    receivedData!.append(data)
+                } else {
+                    receivedData = data
+                }
+            }
+            
+            if eof {
+                completionHandler(receivedData, nil)
+            } else {
+                self.readDataUntilEOF(of: task, minLength: 0, receivedData: receivedData, timeout: timeout, completionHandler: completionHandler)
+            }
+            
+        }
+    }
+    
+    func execute(command: String, on task: FileProviderStreamTask, minLength: Int = 4, afterSend: ((_ error: Error?) -> Void)? = nil, completionHandler: @escaping (_ response: String?, _ error: Error?) -> Void) {
+        let timeout = session.configuration.timeoutIntervalForRequest
+        let terminalcommand = command + "\r\n"
+        task.write(terminalcommand.data(using: .utf8)!, timeout: timeout) { (error) in
+            if let error = error {
+                completionHandler(nil, error)
+                return
+            }
+            afterSend?(error)
+            
+            if task.state == .suspended {
+                task.resume()
+            }
+            
+            task.readData(ofMinLength: minLength, maxLength: 1024, timeout: timeout) { (data, eof, error) in
+                if let error = error {
+                    completionHandler(nil, error)
+                    return
+                }
+                
+                if let data = data, let response = String(data: data, encoding: .utf8) {
+                    completionHandler(response.trimmingCharacters(in: .whitespacesAndNewlines), nil)
+                } else {
+                    completionHandler(nil, self.throwError("", code: URLError.cannotParseResponse))
+                    return
+                }
+            }
+        }
+    }
+    
+    func ftpLogin(_ task: FileProviderStreamTask, completionHandler: @escaping (_ error: Error?) -> Void) {
+        let timeout = session.configuration.timeoutIntervalForRequest
+        if task.state == .suspended {
+            task.resume()
+        }
+        
+        var isSecure = false
+        // Implicit FTP Connection
+        if self.baseURL?.port == 990 || self.baseURL?.scheme == "ftps" {
+            task.startSecureConnection()
+            isSecure = true
+        }
+        
+        let credential = self.credential
+        
+        task.readData(ofMinLength: 4, maxLength: 2048, timeout: timeout) { (data, eof, error) in
+            if let error = error {
+                completionHandler(error)
+                return
+            }
+            
+            guard let data = data, let response = String(data: data, encoding: .utf8) else {
+                completionHandler(self.throwError("", code: URLError.cannotParseResponse))
+                return
+            }
+            
+            guard response.hasPrefix("22") else {
+                let error = FileProviderFTPError(message: response)
+                completionHandler(error)
+                return
+            }
+            
+            let loginHandle: () -> Void = {
+                self.execute(command: "USER \(credential?.user ?? "anonymous")", on: task) { (response, error) in
+                    if let error = error {
+                        completionHandler(error)
+                        return
+                    }
+                    
+                    guard let response = response else {
+                        completionHandler(self.throwError("", code: URLError.badServerResponse))
+                        return
+                    }
+                    
+                    // successfully logged in
+                    if response.hasPrefix("23") {
+                        completionHandler(nil)
+                        return
+                    }
+                    
+                    // needs password
+                    if FileProviderFTPError(message: response).code == 331 {
+                        self.execute(command: "PASS \(credential?.password ?? "fileprovider@")", on: task) { (response, error) in
+                            if response?.hasPrefix("23") ?? false {
+                                completionHandler(nil)
+                            } else {
+                                completionHandler(self.throwError("", code: URLError.userAuthenticationRequired))
+                            }
+                        }
+                        return
+                    }
+                    
+                    let error = FileProviderFTPError(message: response)
+                    completionHandler(error)
+                    return
+                }
+            }
+            
+            if !isSecure && self.baseURL?.scheme == "ftpes" {
+                // Explicit FTP Connection, by upgrading connection to FTP/SSL
+                self.execute(command: "AUTH TLS", on: task, minLength: 0, completionHandler: { (response, error) in
+                    if let error = error {
+                        completionHandler(error)
+                        return
+                    }
+                    
+                    if let response = response, response.hasPrefix("23") {
+                        task.startSecureConnection()
+                        isSecure = true
+                        self.execute(command: "PBSZ 0\r\nPROT P", on: task, completionHandler: { (response, error) in
+                            if let error = error {
+                                completionHandler(error)
+                                return
+                            }
+                            
+                            loginHandle()
+                        })
+                    }
+                })
+            } else if isSecure {
+                self.execute(command: "PBSZ 0\r\nPROT P", on: task, completionHandler: { (response, error) in
+                    if let error = error {
+                        completionHandler(error)
+                        return
+                    }
+                    
+                    loginHandle()
+                })
+            } else {
+                loginHandle()
+            }
+        }
+    }
+    
+    func ftpCwd(_ task: FileProviderStreamTask, to path: String, completionHandler: @escaping (_ error: Error?) -> Void) {
+        self.execute(command: "CWD \(path)", on: task) { (response, error) in
+            if let error = error {
+                completionHandler(error)
+                return
+            }
+            
+            guard let response = response else {
+                completionHandler(self.throwError(path, code: URLError.badServerResponse))
+                return
+            }
+            
+            // successfully logged in
+            if response.hasPrefix("25") {
+                completionHandler(nil)
+            }
+            // not logged in
+            else if response.hasPrefix("55") {
+                let error = FileProviderFTPError(message: response)
+                completionHandler(error)
+                return
+            }
+        }
+    }
+    
+    func ftpPassive(_ task: FileProviderStreamTask, completionHandler: @escaping (_ dataTask: FileProviderStreamTask?, _ error: Error?) -> Void) {
+        func trimmedNumber(_ s : String) -> String {
+            let characterSet = Set("+*#0123456789".characters)
+            return String(s.characters.lazy.filter(characterSet.contains))
+        }
+        
+        self.execute(command: "PASV", on: task) { (response, error) in
+            if let error = error {
+                completionHandler(nil, error)
+                return
+            }
+            
+            guard let response = response, let destString = response.components(separatedBy: " ").flatMap({ $0 }).last.flatMap({ String($0) }) else {
+                completionHandler(nil, self.throwError("", code: URLError.badServerResponse))
+                return
+            }
+            
+            let destArray = destString.components(separatedBy: ",").flatMap({ UInt32(trimmedNumber($0)) })
+            guard destArray.count == 6 else {
+                completionHandler(nil, self.throwError("", code: URLError.badServerResponse))
+                return
+            }
+            
+            // first 4 elements are ip, 2 next are port, as byte
+            var host = destArray.prefix(4).flatMap({ String($0) }).joined(separator: ".")
+            let port = Int(destArray[4] << 8 + destArray[5])
+            // IPv6 workaround
+            if host == "127.555.555.555" {
+                host = self.baseURL!.host!
+            }
+            
+            let passiveTask = self.session.fpstreamTask(withHostName: host, port: port)
+            passiveTask.resume()
+            if self.baseURL?.scheme == "ftps" || self.baseURL?.scheme == "ftpes" || self.baseURL?.port == 990 {
+                passiveTask.startSecureConnection()
+            }
+            completionHandler(passiveTask, nil)
+        }
+    }
+    
+    func ftpActive(_ task: FileProviderStreamTask, completionHandler: @escaping (_ dataTask: FileProviderStreamTask?, _ error: Error?) -> Void) {
+        let service = NetService(domain: "", type: "_tcp.", name: "", port: 0)
+        service.publish(options: .listenForConnections)
+        let startTime = Date()
+        while service.port < 1 && startTime.timeIntervalSinceNow > -self.session.configuration.timeoutIntervalForRequest {
+            usleep(100_000)
+        }
+        let activeTask = self.session.fpstreamTask(withNetService: service)
+        activeTask.resume()
+        if self.baseURL?.scheme == "ftps" || self.baseURL?.port == 990 {
+            activeTask.startSecureConnection()
+        }
+        
+        self.execute(command: "PORT \(service.port)", on: task) { (response, error) in
+            if let error = error {
+                activeTask.cancel()
+                completionHandler(nil, error)
+                return
+            }
+            
+            guard let response = response else {
+                activeTask.cancel()
+                completionHandler(nil, self.throwError("", code: URLError.badServerResponse))
+                return
+            }
+            
+            guard !response.hasPrefix("5") else {
+                activeTask.cancel()
+                completionHandler(nil, self.throwError("", code: URLError.cannotConnectToHost))
+                return
+            }
+            
+            completionHandler(activeTask, nil)
+        }
+    }
+    
+    func ftpDataConnect(_ task: FileProviderStreamTask, completionHandler: @escaping (_ dataTask: FileProviderStreamTask?, _ error: Error?) -> Void) {
+        if self.passiveMode {
+            self.ftpPassive(task, completionHandler: completionHandler)
+        } else {
+            dispatch_queue.async {
+                self.ftpActive(task, completionHandler: completionHandler)
+            }
+        }
+    }
+    
+    func ftpRest(_ task: FileProviderStreamTask, startPosition: Int64, completionHandler: @escaping (_ error: Error?) -> Void) {
+        self.execute(command: "REST \(startPosition)", on: task) { (response, error) in
+            if let error = error {
+                completionHandler(error)
+                return
+            }
+            
+            // Successful
+            guard let response = response else {
+                completionHandler(self.throwError("", code: URLError.badServerResponse))
+                return
+            }
+            
+            if response.hasPrefix("35") {
+                completionHandler(nil)
+            } else {
+                let error = FileProviderFTPError(message: response, path: "")
+                completionHandler(error)
+                return
+            }
+        }
+    }
+    
+    func ftpList(_ task: FileProviderStreamTask, of path: String, useMLST: Bool, completionHandler: @escaping (_ contents: [String], _ error: Error?) -> Void) {
+        self.ftpDataConnect(task) { (dataTask, error) in
+            if let error = error {
+                completionHandler([], error)
+                return
+            }
+            
+            guard let dataTask = dataTask else {
+                completionHandler([], self.throwError(path, code: URLError.badServerResponse))
+                return
+            }
+            
+            var success = false
+            let command = useMLST ? "MLSD \(path)" : "LIST \(path)"
+            self.execute(command: command, on: task, minLength: 20, afterSend: { error in
+                // starting passive task
+                let timeout = self.session.configuration.timeoutIntervalForRequest
+                
+                DispatchQueue.global().async {
+                    var finalData = Data()
+                    var eof = false
+                    var error: Error?
+                    while !eof {
+                        let group = DispatchGroup()
+                        group.enter()
+                        dataTask.readData(ofMinLength: 1, maxLength: 65535, timeout: timeout, completionHandler: { (data, seof, serror) in
+                            if let data = data {
+                                finalData.append(data)
+                            }
+                            eof = seof
+                            error = serror
+                            group.leave()
+                        })
+                        let waitResult = group.wait(timeout: .now() + timeout)
+                        
+                        if let error = error {
+                            if !((error as NSError).domain == URLError.errorDomain && (error as NSError).code == URLError.cancelled.rawValue) {
+                                completionHandler([], error)
+                            }
+                            return
+                        }
+                        
+                        if waitResult == .timedOut {
+                            completionHandler([], self.throwError(path, code: URLError.timedOut))
+                            return
+                        }
+                    }
+                    
+                    guard let response = String(data: finalData, encoding: .utf8) else {
+                        completionHandler([], self.throwError(path, code: URLError.badServerResponse))
+                        return
+                    }
+                    
+                    let contents: [String] = response.components(separatedBy: "\n").flatMap({ $0.trimmingCharacters(in: .whitespacesAndNewlines) })
+                    success = true
+                    completionHandler(contents, nil)
+                    return
+                }
+            }) { (response, error) in
+                if let error = error {
+                    completionHandler([], error)
+                    return
+                }
+                
+                guard let response = response else {
+                    completionHandler([], self.throwError(path, code: URLError.cannotParseResponse))
+                    return
+                }
+                
+                if response.hasPrefix("500") && useMLST {
+                    dataTask.cancel()
+                    self.serverSupportsRFC3659 = false
+                    completionHandler([], self.throwError(path, code: URLError.unsupportedURL))
+                    return
+                }
+                
+                if !success && !(response.hasPrefix("25") || response.hasPrefix("15")) {
+                    let error = FileProviderFTPError(message: response, path: path)
+                    self.dispatch_queue.async {
+                        completionHandler([], error)
+                    }
+                    return
+                }
+            }
+        }
+    }
+    
+    func recursiveList(path: String, useMLST: Bool, foundItemsHandler: ((_ contents: [FileObject]) -> Void)? = nil, completionHandler: @escaping (_ contents: [FileObject], _ error: Error?) -> Void) -> Progress? {
+        let progress = Progress(totalUnitCount: 0)
+        let queue = DispatchQueue(label: "\(self.type).recursiveList")
+        queue.async {
+            let group = DispatchGroup()
+            var result = [FileObject]()
+            var success = true
+            group.enter()
+            self.contentsOfDirectory(path: path, completionHandler: { (files, error) in
+                success = success && (error == nil)
+                if let error = error {
+                    completionHandler([], error)
+                    group.leave()
+                    return
+                }
+                
+                result.append(contentsOf: files)
+                progress.completedUnitCount = Int64(files.count)
+                foundItemsHandler?(files)
+                
+                let directories: [FileObject] = files.filter { $0.isDirectory }
+                progress.becomeCurrent(withPendingUnitCount: Int64(directories.count))
+                for dir in directories {
+                    group.enter()
+                    _=self.recursiveList(path: dir.path, useMLST: useMLST, foundItemsHandler: foundItemsHandler, completionHandler: { (contents, error) in
+                        success = success && (error == nil)
+                        if let error = error {
+                            completionHandler([], error)
+                            group.leave()
+                            return
+                        }
+                        
+                        foundItemsHandler?(files)
+                        result.append(contentsOf: contents)
+                        
+                        group.leave()
+                    })
+                }
+                progress.resignCurrent()
+                group.leave()
+            })
+            group.wait()
+            
+            if success {
+                self.dispatch_queue.async {
+                    completionHandler(result, nil)
+                }
+            }
+        }
+        return progress
+    }
+    
+    func ftpRetrieveData(_ task: FileProviderStreamTask, filePath: String, from position: Int64 = 0, length: Int = -1, onTask: ((_ task: FileProviderStreamTask) -> Void)?, onProgress: ((_ bytesReceived: Int64, _ totalReceived: Int64, _ expectedBytes: Int64) -> Void)?, completionHandler: @escaping (_ data: Data?, _ error: Error?) -> Void) {
+        
+        // Check cache
+        if useCache, let url = URL(string: filePath.addingPercentEncoding(withAllowedCharacters: .urlPathAllowed) ?? filePath, relativeTo: self.baseURL!)?.absoluteURL, let cachedResponse = self.cache?.cachedResponse(for: URLRequest(url: url)), cachedResponse.data.count > 0 {
+            dispatch_queue.async {
+                completionHandler(cachedResponse.data, nil)
+            }
+            return
+        }
+        
+        self.attributesOfItem(path: filePath) { (file, error) in
+            let totalSize = file?.size ?? -1
+            // Retreive data from server
+            self.ftpDataConnect(task) { (dataTask, error) in
+                if let error = error {
+                    completionHandler(nil, error)
+                    return
+                }
+                
+                guard let dataTask = dataTask else {
+                    completionHandler(nil, self.throwError(filePath, code: URLError.badServerResponse))
+                    return
+                }
+                
+                // Send retreive command
+                let len = 19 /* TYPE response */ + 65 + String(position).characters.count /* REST Response */ + 53 + filePath.characters.count + String(totalSize).characters.count /* RETR open response */ + 26 /* RETR Transfer complete message. */
+                self.execute(command: "TYPE I" + "\r\n" + "REST \(position)" + "\r\n" + "RETR \(filePath)", on: task, minLength: len, afterSend: { error in
+                    // starting passive task
+                    onTask?(dataTask)
+                    
+                    let timeout = self.session.configuration.timeoutIntervalForRequest
+                    DispatchQueue.global().async {
+                        var finalData = Data()
+                        var eof = false
+                        var error: Error?
+                        while !eof {
+                            let group = DispatchGroup()
+                            group.enter()
+                            dataTask.readData(ofMinLength: 0, maxLength: 65535, timeout: timeout, completionHandler: { (data, seof, serror) in
+                                if let data = data {
+                                    finalData.append(data)
+                                    onProgress?(Int64(data.count), Int64(finalData.count), totalSize)
+                                }
+                                eof = seof || (length > 0 && finalData.count >= length)
+                                if length > 0 && finalData.count > length {
+                                    finalData.count = length
+                                }
+                                error = serror
+                                group.leave()
+                            })
+                            let waitResult = group.wait(timeout: .now() + timeout)
+                            
+                            if let error = error {
+                                completionHandler(nil, error)
+                                return
+                            }
+                            
+                            if waitResult == .timedOut {
+                                completionHandler(nil, self.throwError(filePath, code: URLError.timedOut))
+                                return
+                            }
+                        }
+                        
+                        if let url = URL(string: filePath.addingPercentEncoding(withAllowedCharacters: .urlPathAllowed) ?? filePath, relativeTo: self.baseURL!)?.absoluteURL {
+                            let urlresponse = URLResponse(url: url, mimeType: nil, expectedContentLength: finalData.count, textEncodingName: nil)
+                            let cachedResponse = CachedURLResponse(response: urlresponse, data: finalData)
+                            let request = URLRequest(url: url)
+                            self.cache?.storeCachedResponse(cachedResponse, for: request)
+                        }
+                        
+                        completionHandler(finalData, nil)
+                        return
+                    }
+                }) { (response, error) in
+                    if let error = error {
+                        completionHandler(nil, error)
+                        return
+                    }
+                    
+                    guard let response = response else {
+                        completionHandler(nil, self.throwError(filePath, code: URLError.cannotParseResponse))
+                        return
+                    }
+                    
+                    if !(response.hasPrefix("1") || !response.hasPrefix("2")) {
+                        let error = FileProviderFTPError(message: response)
+                        
+                        self.dispatch_queue.async {
+                            completionHandler(nil, error)
+                        }
+                        return
+                    }
+                }
+            }
+        }
+    }
+    
+    func ftpRetrieveFile(_ task: FileProviderStreamTask, filePath: String, from position: Int64 = 0, length: Int = -1, onTask: ((_ task: FileProviderStreamTask) -> Void)?, onProgress: ((_ bytesReceived: Int64, _ totalReceived: Int64, _ expectedBytes: Int64) -> Void)?, completionHandler: @escaping (_ file: URL?, _ error: Error?) -> Void) {
+        let tempURL = URL(fileURLWithPath: NSTemporaryDirectory()).appendingPathComponent(UUID().uuidString).appendingPathExtension("tmp")
+        
+        // Check cache
+        if useCache, let url = URL(string: filePath.addingPercentEncoding(withAllowedCharacters: .urlPathAllowed) ?? filePath, relativeTo: self.baseURL!)?.absoluteURL, let cachedResponse = self.cache?.cachedResponse(for: URLRequest(url: url)), cachedResponse.data.count > 0 {
+            dispatch_queue.async {
+                do {
+                    try cachedResponse.data.write(to: tempURL)
+                    completionHandler(tempURL, nil)
+                } catch {
+                    completionHandler(nil, error)
+                }
+                try? FileManager.default.removeItem(at: tempURL)
+            }
+            return
+        }
+        
+        self.attributesOfItem(path: filePath) { (file, error) in
+            let totalSize = file?.size ?? -1
+            // Retreive data from server
+            self.ftpDataConnect(task) { (dataTask, error) in
+                if let error = error {
+                    completionHandler(nil, error)
+                    return
+                }
+                
+                guard let dataTask = dataTask else {
+                    completionHandler(nil, self.throwError(filePath, code: URLError.badServerResponse))
+                    return
+                }
+                
+                // Send retreive command
+                let len = 19 /* TYPE response */ + 65 + String(position).characters.count /* REST Response */ + 53 + filePath.characters.count + String(totalSize).characters.count /* RETR open response */ + 26 /* RETR Transfer complete message. */
+                self.execute(command: "TYPE I"  + "\r\n" + "REST \(position)" + "\r\n" + "RETR \(filePath)", on: task, minLength: len, afterSend: { error in
+                    // starting passive task
+                    onTask?(dataTask)
+                    
+                    let timeout = self.session.configuration.timeoutIntervalForRequest
+                    DispatchQueue.global().async {
+                        var finalData = Data()
+                        var eof = false
+                        var error: Error?
+                        while !eof {
+                            let group = DispatchGroup()
+                            group.enter()
+                            dataTask.readData(ofMinLength: 0, maxLength: 65535, timeout: timeout, completionHandler: { (data, seof, serror) in
+                                if let data = data {
+                                    finalData.append(data)
+                                    onProgress?(Int64(data.count), Int64(finalData.count), totalSize)
+                                }
+                                eof = seof || (length > 0 && finalData.count >= length)
+                                if length > 0 && finalData.count > length {
+                                    finalData.count = length
+                                }
+                                error = serror
+                                group.leave()
+                            })
+                            let waitResult = group.wait(timeout: .now() + timeout)
+                            
+                            if let error = error {
+                                completionHandler(nil, error)
+                                return
+                            }
+                            
+                            if waitResult == .timedOut {
+                                error = self.throwError("", code: URLError.timedOut)
+                                completionHandler(nil, error)
+                                return
+                            }
+                        }
+                        
+                        if let url = URL(string: filePath.addingPercentEncoding(withAllowedCharacters: .urlPathAllowed) ?? filePath, relativeTo: self.baseURL!)?.absoluteURL {
+                            let urlresponse = URLResponse(url: url, mimeType: nil, expectedContentLength: finalData.count, textEncodingName: nil)
+                            let cachedResponse = CachedURLResponse(response: urlresponse, data: finalData)
+                            let request = URLRequest(url: url)
+                            self.cache?.storeCachedResponse(cachedResponse, for: request)
+                        }
+                        
+                        self.dispatch_queue.async {
+                            do {
+                                try finalData.write(to: tempURL)
+                                completionHandler(tempURL, nil)
+                            } catch {
+                                completionHandler(nil, error)
+                            }
+                            try? FileManager.default.removeItem(at: tempURL)
+                        }
+                        return
+                    }
+                }) { (response, error) in
+                    if let error = error {
+                        completionHandler(nil, error)
+                        return
+                    }
+                    
+                    guard let response = response else {
+                        completionHandler(nil, self.throwError(filePath, code: URLError.cannotParseResponse))
+                        return
+                    }
+                    
+                    if !(response.hasPrefix("1") || response.hasPrefix("2")) {
+                        let error = FileProviderFTPError(message: response)
+                        
+                        self.dispatch_queue.async {
+                            completionHandler(nil, error)
+                        }
+                        return
+                    }
+                }
+            }
+        }
+    }
+    
+    func ftpStore(_ task: FileProviderStreamTask, filePath: String, fromData: Data?, fromFile: URL?, onTask: ((_ task: FileProviderStreamTask) -> Void)?,  onProgress: ((_ bytesSent: Int64, _ totalSent: Int64, _ expectedBytes: Int64) -> Void)?, completionHandler: @escaping (_ error: Error?) -> Void) {
+        let timeout = self.session.configuration.timeoutIntervalForRequest
+        operation_queue.addOperation {
+            guard let size: Int64 = (fromData != nil ? Int64(fromData!.count) : nil) ?? fromFile?.fileSize else { return }
+            
+            var error: Error?
+            let chunkSize: Int
+            switch size {
+            case 0..<262_144: chunkSize = 32_768 // 0KB To 256KB, page size is 32KB
+            case 262_144..<1_048_576: chunkSize = 65_536 // 256KB To 1MB, page size is 64KB
+            case 1_048_576..<10_485_760: chunkSize = 131_072 // 1MB To 10MB, page size is 128KB
+            case 10_048_576..<33_554_432: chunkSize = 262_144 // 1MB To 10MB, page size is 256KB
+            default: chunkSize = 524_288 // Larger than 32MB, page size is 512KB
+            }
+            
+            var fileHandle: FileHandle?
+            if let file = fromFile {
+                fileHandle = FileHandle(forReadingAtPath: file.path)
+            }
+            defer {
+                fileHandle?.closeFile()
+            }
+            
+            var eof = false
+            var sent: Int64 = 0
+            
+            while !eof {
+                let subdata: Data
+                if let data = fromData {
+                    let endIndex = min(data.count, Int(sent) + chunkSize)
+                    eof = endIndex == data.count
+                    subdata = data.subdata(in: Int(sent)..<endIndex)
+                }else if let fileHandle = fileHandle {
+                    subdata = fileHandle.readData(ofLength: chunkSize)
+                    eof = Int64(fileHandle.offsetInFile) == size
+                } else {
+                    return
+                }
+                if subdata.count == 0 { continue }
+                
+                let group = DispatchGroup()
+                group.enter()
+                self.ftpStore(task, data: subdata, to: filePath, from: sent, onTask: onTask, completionHandler: { (serror) in
+                    error = serror
+                    sent += Int64(subdata.count)
+                    group.leave()
+                    onProgress?(Int64(subdata.count), sent, size)
+                })
+                let waitResult = group.wait(timeout: .now() + timeout)
+                
+                if waitResult == .timedOut {
+                    error = self.throwError(filePath, code: URLError.timedOut)
+                    completionHandler(error)
+                    return
+                }
+                if let error = error {
+                    completionHandler(error)
+                    return
+                }
+            }
+            completionHandler(nil)
+        }
+    }
+    
+    func ftpStore(_ task: FileProviderStreamTask, data: Data, to filePath: String, from position: Int64, onTask: ((_ task: FileProviderStreamTask) -> Void)?, completionHandler: @escaping (_ error: Error?) -> Void) {
+        self.ftpDataConnect(task) { (dataTask, error) in
+            if let error = error {
+                completionHandler(error)
+                return
+            }
+            
+            guard let dataTask = dataTask else {
+                completionHandler(self.throwError(filePath, code: URLError.badServerResponse))
+                return
+            }
+            
+            // Send retreive command
+            var success = false
+            let len = 19 /* TYPE response */ + 65 + String(position).characters.count /* REST Response */ + 44 + filePath.characters.count /* STOR open response */ + 10 /* RETR Transfer complete message. */
+            self.execute(command: "TYPE I"  + "\r\n" + "REST \(position)"  + "\r\n" + "STOR \(filePath)", on: task, minLength: len, afterSend: { error in
+                // starting passive task
+                let timeout = self.session.configuration.timeoutIntervalForRequest
+                if self.baseURL?.scheme == "ftps" || self.baseURL?.port == 990 {
+                    task.startSecureConnection()
+                }
+                onTask?(dataTask)
+                
+                if data.count == 0 { return }
+                
+                dataTask.write(data, timeout: timeout, completionHandler: { (error) in
+                    if let error = error {
+                        completionHandler(error)
+                        return
+                    }
+                    success = true
+                    
+                    dataTask.closeRead()
+                    dataTask.closeWrite()
+                })
+            }) { (response, error) in
+                guard success else { return }
+                
+                if let error = error {
+                    completionHandler(error)
+                    return
+                }
+                
+                guard let response = response else {
+                    completionHandler(self.throwError(filePath, code: URLError.cannotParseResponse))
+                    return
+                }
+                
+                if !(response.hasPrefix("1") || response.hasPrefix("2")) {
+                    let error = FileProviderFTPError(message: response)
+                    
+                    self.dispatch_queue.async {
+                        completionHandler(error)
+                    }
+                    return
+                }
+                
+                completionHandler(nil)
+            }
+        }
+    }
+    
+    func ftpQuit(_ task: FileProviderStreamTask) {
+        self.execute(command: "QUIT", on: task) { (_, _) in
+            //task.closeRead()
+            //task.closeWrite()
+        }
+    }
+    
+    func ftpPath(_ apath: String) -> String {
+        var path = apath.isEmpty ? self.currentPath : apath
+        
+        // path of base url should be concreted into file path!
+        path = baseURL!.appendingPathComponent(path).path
+        
+        // Fixing slashes
+        if !path.hasPrefix("/") {
+            path = "/" + path
+        }
+        if path.hasSuffix("/"){
+            path.characters.removeLast()
+        }
+        
+        if path.isEmpty {
+            path = "/"
+        }
+        
+        return path
+    }
+    
+    func parseUnixList(_ text: String, in path: String) -> FileObject? {
+        let gregorian = Calendar(identifier: .gregorian)
+        let nearDateFormatter = DateFormatter()
+        nearDateFormatter.calendar = gregorian
+        nearDateFormatter.locale = Locale(identifier: "en_US_POSIX")
+        nearDateFormatter.dateFormat = "MMM dd hh:ss yyyy"
+        let farDateFormatter = DateFormatter()
+        farDateFormatter.calendar = gregorian
+        farDateFormatter.locale = Locale(identifier: "en_US_POSIX")
+        farDateFormatter.dateFormat = "MMM dd yyyy"
+        let thisYear = gregorian.component(.year, from: Date())
+        
+        let components = text.components(separatedBy: " ").flatMap { $0.isEmpty ? nil : $0 }
+        guard components.count >= 9 else { return nil }
+        let posixPermission = components[0]
+        let linksCount = Int(components[1]) ?? 0
+        //let owner = components[2]
+        //let groupOwner = components[3]
+        let size = Int64(components[4]) ?? -1
+        let date = components[5..<8].joined(separator: " ")
+        let name = components[8..<components.count].joined(separator: " ")
+        
+        guard name != "." && name != ".." else { return nil }
+        var path = (path as NSString).appendingPathComponent(name)
+        if path.hasPrefix("/") {
+            path.characters.removeFirst()
+        }
+        
+        let file = FileObject(url: url(of: path), name: name, path: path)
+        switch String(posixPermission.characters.first!) {
+        case "d": file.type = .directory
+        case "l": file.type = .symbolicLink
+        default:  file.type = .regular
+        }
+        file.isReadOnly = !posixPermission.contains("w")
+        file.size = file.isDirectory ? -1 : size
+        file.allValues[.linkCountKey] = linksCount
+        
+        if let parsedDate = nearDateFormatter.date(from: date + " " + String(thisYear)) {
+            if parsedDate > Date() {
+                file.modifiedDate = gregorian.date(byAdding: .year, value: -1, to: parsedDate)
+            } else {
+                file.modifiedDate = parsedDate
+            }
+        } else if let parsedDate = farDateFormatter.date(from: date) {
+            file.modifiedDate = parsedDate
+        }
+        
+        return file
+    }
+    
+    func parseMLST(_ text: String, in path: String) -> FileObject? {
+        var components = text.components(separatedBy: ";").flatMap { $0.isEmpty ? nil : $0 }
+        guard components.count > 1 else { return nil }
+        
+        let nameOrPath = components.removeLast().trimmingCharacters(in: .whitespacesAndNewlines)
+        var correctedPath: String
+        let name: String
+        if nameOrPath.hasPrefix("/") {
+            correctedPath = nameOrPath.replacingOccurrences(of: baseURL!.path, with: "", options: .anchored)
+            name = (nameOrPath as NSString).lastPathComponent
+        } else {
+            name = nameOrPath
+            correctedPath = (path as NSString).appendingPathComponent(nameOrPath)
+        }
+        if correctedPath.hasPrefix("/") {
+            correctedPath.characters.removeFirst()
+        }
+        
+        var attributes = [String: String]()
+        for component in components {
+            let keyValue = component.components(separatedBy: "=") .flatMap { $0.isEmpty ? nil : $0 }
+            guard keyValue.count >= 2, !keyValue[0].isEmpty else { continue }
+            attributes[keyValue[0].lowercased()] = keyValue.dropFirst().joined(separator: "=")
+        }
+        
+        let file = FileObject(url: url(of: correctedPath), name: name, path: correctedPath)
+        let dateFormatter = DateFormatter()
+        dateFormatter.calendar = Calendar(identifier: .gregorian)
+        dateFormatter.locale = Locale(identifier: "en_US_POSIX")
+        dateFormatter.dateFormat = "yyyyMMddhhmmss"
+        for (key, attribute) in attributes {
+            switch key {
+            case "type":
+                switch attribute.lowercased() {
+                case "file": file.type = .regular
+                case "dir": file.type = .directory
+                case "link": file.type = .symbolicLink
+                case "os.unix=block": file.type = .blockSpecial
+                case "cdir", "pdir": return nil // . and .. files are redundant in listing
+                default: file.type = .unknown
+                }
+                
+            case "unique":
+                file.allValues[.fileResourceIdentifierKey] = attribute
+                
+            case "modify":
+                file.modifiedDate = dateFormatter.date(from: attribute)
+            
+            case "create":
+                file.creationDate = dateFormatter.date(from: attribute)
+                
+            case "perm":
+                file.allValues[.isReadableKey] = attribute.contains("r") || attribute.contains("l")
+                file.allValues[.isWritableKey] = attribute.contains("w") || attribute.contains("a")
+                
+            case "size":
+                file.size = Int64(attribute) ?? -1
+                
+            case "media-type":
+                file.allValues[.mimeTypeKey] = attribute
+                
+            default:
+                break
+            }
+        }
+        
+        return file
+    }
+}
+
+/// Contains error code and description returned by FTP/S provider.
+public struct FileProviderFTPError: Error {
+    /// HTTP status code returned for error by server.
+    public let code: Int
+    /// Path of file/folder casued that error
+    public let path: String
+    /// Contents returned by server as error description
+    public let errorDescription: String?
+    
+    init(code: Int, path: String, errorDescription: String?) {
+        self.code = code
+        self.path = path
+        self.errorDescription = errorDescription
+    }
+    
+    init(message response: String, path: String = "") {
+        let message = response.components(separatedBy: .newlines).last ?? "No Response"
+        let spaceIndex = message.characters.index(of: "-") ?? message.characters.index(of: " ") ?? message.startIndex
+        self.code = Int(message.substring(to: spaceIndex).trimmingCharacters(in: .whitespacesAndNewlines)) ?? -1
+        self.path = path
+        if code > 0 {
+            self.errorDescription = message.substring(from: spaceIndex).trimmingCharacters(in: .whitespacesAndNewlines)
+        } else {
+            self.errorDescription = message
+        }
+    }
+}
@@ -0,0 +1,301 @@
+//
+//  FileProvider.swift
+//  FileProvider
+//
+//  Created by Amir Abbas Mousavian.
+//  Copyright © 2016 Mousavian. Distributed under MIT license.
+//
+
+import Foundation
+
+/// Containts path, url and attributes of a file or resource.
+open class FileObject: Equatable {
+    /// A `Dictionary` contains file information,  using `URLResourceKey` keys.
+    open internal(set) var allValues: [URLResourceKey: Any]
+    
+    public init(allValues: [URLResourceKey: Any]) {
+        self.allValues = allValues
+    }
+    
+    internal init(url: URL?, name: String, path: String) {
+        self.allValues = [URLResourceKey: Any]()
+        if let url = url {
+            self.url = url
+        }
+        self.name = name
+        self.path = path
+    }
+    
+    /// URL to access the resource, can be a relative URL against base URL.
+    /// not supported by Dropbox provider.
+    open internal(set) var url: URL {
+        get {
+            if let url = allValues[.fileURLKey] as? URL {
+                return url
+            } else {
+                let path = self.path.addingPercentEncoding(withAllowedCharacters: .urlPathAllowed) ?? self.path
+                return URL(string: path) ?? URL(string: "/")!
+            }
+        }
+        set {
+            allValues[.fileURLKey] = newValue
+        }
+    }
+    
+    /// Name of the file, usually equals with the last path component
+    open internal(set) var name: String {
+        get {
+            return allValues[.nameKey] as! String
+        }
+        set {
+            allValues[.nameKey] = newValue
+        }
+    }
+    
+    /// Relative path of file object
+    open internal(set) var path: String {
+        get {
+            return allValues[.pathKey] as! String
+        }
+        set {
+            allValues[.pathKey] = newValue
+        }
+    }
+    
+    /// Size of file on disk, return -1 for directories.
+    open internal(set) var size: Int64 {
+        get {
+            return allValues[.fileSizeKey] as? Int64 ?? -1
+        }
+        set {
+            allValues[.fileSizeKey] = newValue
+        }
+    }
+    
+    /// The time contents of file has been created, returns nil if not set
+    open internal(set) var creationDate: Date? {
+        get {
+            return allValues[.creationDateKey] as? Date
+        }
+        set {
+            allValues[.creationDateKey] = newValue
+        }
+    }
+    
+    /// The time contents of file has been modified, returns nil if not set
+    open internal(set) var modifiedDate: Date? {
+        get {
+            return allValues[.contentModificationDateKey] as? Date
+        }
+        set {
+            allValues[.contentModificationDateKey] = newValue
+        }
+    }
+    
+    /// return resource type of file, usually directory, regular or symLink
+    open internal(set) var type: URLFileResourceType? {
+        get {
+            return allValues[.fileResourceTypeKey] as? URLFileResourceType
+        }
+        set {
+            allValues[.fileResourceTypeKey] = newValue
+        }
+    }
+    
+    /// File is hidden either because begining with dot or filesystem flags
+    /// Setting this value on a file begining with dot has no effect
+    open internal(set) var isHidden: Bool {
+        get {
+            return allValues[.isHiddenKey] as? Bool ?? false
+        }
+        set {
+            allValues[.isHiddenKey] = newValue
+        }
+    }
+    
+    /// File can not be written
+    open internal(set) var isReadOnly: Bool {
+        get {
+            return !(allValues[.isWritableKey] as? Bool ?? true)
+        }
+        set {
+            allValues[.isWritableKey] = !newValue
+        }
+    }
+    
+    /// File is a Directory
+    open var isDirectory: Bool {
+        return self.type == .directory
+    }
+    
+    /// File is a normal file
+    open var isRegularFile: Bool {
+        return self.type == .regular
+    }
+    
+    /// File is a Symbolic link
+    open var isSymLink: Bool {
+        return self.type == .symbolicLink
+    }
+    
+    /// Check `FileObject` equality
+    public static func ==(lhs: FileObject, rhs: FileObject) -> Bool {
+        if rhs === lhs  {
+            return true
+        }
+        #if swift(>=3.1)
+        if Swift.type(of: lhs) != Swift.type(of: rhs) {
+            return false
+        }
+        #else
+        if type(of: lhs) != type(of: rhs) {
+            return false
+        }
+        #endif
+        
+        if let rurl = rhs.allValues[.fileURLKey] as? URL, let lurl = lhs.allValues[.fileURLKey] as? URL {
+            return rurl == lurl
+        }
+        return rhs.path == lhs.path && rhs.size == lhs.size && rhs.modifiedDate == lhs.modifiedDate
+    }
+    
+    internal func mapPredicate() -> [String: Any] {
+        let mapDict: [URLResourceKey: String] = [.fileURLKey: "url", .nameKey: "name", .pathKey: "path", .fileSizeKey: "filesize", .creationDateKey: "creationDate",
+                                                 .contentModificationDateKey: "modifiedDate", .isHiddenKey: "isHidden", .isWritableKey: "isWritable", .serverDateKey: "serverDate", .entryTagKey: "entryTag", .mimeTypeKey: "mimeType"]
+        let typeDict: [URLFileResourceType: String] = [.directory: "directory", .regular: "regular", .symbolicLink: "symbolicLink", .unknown: "unknown"]
+        var result = [String: Any]()
+        for (key, value) in allValues {
+            if let convertkey = mapDict[key] {
+                result[convertkey] = value
+            }
+        }
+        result["eTag"] = result["entryTag"]
+        result["isReadOnly"] = self.isReadOnly
+        result["isDirectory"] = self.isDirectory
+        result["isRegularFile"] = self.isRegularFile
+        result["isSymLink"] = self.isSymLink
+        result["type"] = typeDict[self.type ?? .unknown] ?? "unknown"
+        return result
+    }
+    
+    /// Converts macOS spotlight query for searching files to a query that can be used for `searchFiles()` method
+    static public func convertPredicate(fromSpotlight query: NSPredicate) -> NSPredicate {
+        let mapDict: [String: URLResourceKey] = [NSMetadataItemURLKey: .fileURLKey, NSMetadataItemFSNameKey: .nameKey, NSMetadataItemPathKey: .pathKey,
+                                                 NSMetadataItemFSSizeKey: .fileSizeKey, NSMetadataItemFSCreationDateKey: .creationDateKey,
+                                                 NSMetadataItemFSContentChangeDateKey: .contentModificationDateKey, "kMDItemFSInvisible": .isHiddenKey, "kMDItemFSIsWriteable": .isWritableKey, "kMDItemKind": .mimeTypeKey]
+        
+        if let cQuery = query as? NSCompoundPredicate {
+            let newSub = cQuery.subpredicates.map { convertPredicate(fromSpotlight: $0 as! NSPredicate) }
+            switch cQuery.compoundPredicateType {
+            case .and: return NSCompoundPredicate(andPredicateWithSubpredicates: newSub)
+            case .not: return NSCompoundPredicate(notPredicateWithSubpredicate: newSub[0])
+            case .or:  return NSCompoundPredicate(orPredicateWithSubpredicates: newSub)
+            }
+        } else if let cQuery = query as? NSComparisonPredicate {
+            var newLeft = cQuery.leftExpression
+            var newRight = cQuery.rightExpression
+            if newLeft.expressionType == .keyPath, let newKey = mapDict[newLeft.keyPath] {
+                newLeft = NSExpression(forKeyPath: newKey.rawValue)
+            }
+            if newRight.expressionType == .keyPath, let newKey = mapDict[newRight.keyPath] {
+                newRight = NSExpression(forKeyPath: newKey.rawValue)
+            }
+            return NSComparisonPredicate(leftExpression: newLeft, rightExpression: newRight, modifier: cQuery.comparisonPredicateModifier, type: cQuery.predicateOperatorType, options: cQuery.options)
+        } else {
+            return query
+        }
+    }
+}
+
+/// Sorting FileObject array by given criteria, **not thread-safe**
+public struct FileObjectSorting {
+    
+    /// Determines sort kind by which item of File object
+    public enum SortType {
+        /// Sorting by default Finder (case-insensitive) behavior
+        case name
+        /// Sorting by case-sensitive form of file name
+        case nameCaseSensitive
+        /// Sorting by case-in sensitive form of file name
+        case nameCaseInsensitive
+        /// Sorting by file type
+        case `extension`
+        /// Sorting by file modified date
+        case modifiedDate
+        /// Sorting by file creation date
+        case creationDate
+        /// Sorting by file modified date
+        case size
+        
+        /// all sort types
+        static var allItems: [SortType] {
+            return [.name, .nameCaseSensitive, .nameCaseInsensitive, .extension,
+                    .modifiedDate,.creationDate, .size]
+        }
+    }
+    
+    public let sortType: SortType
+    /// puts A before Z, default is true
+    public let ascending: Bool
+    /// puts directories on top, regardless of other attributes, default is false
+    public let isDirectoriesFirst: Bool
+    
+    public static let nameAscending = FileObjectSorting(type: .name, ascending: true)
+    public static let nameDesceding = FileObjectSorting(type: .name, ascending: false)
+    public static let sizeAscending = FileObjectSorting(type: .size, ascending: true)
+    public static let sizeDesceding = FileObjectSorting(type: .size, ascending: false)
+    public static let extensionAscending = FileObjectSorting(type: .extension, ascending: true)
+    public static let extensionDesceding = FileObjectSorting(type: .extension, ascending: false)
+    public static let modifiedAscending = FileObjectSorting(type: .modifiedDate, ascending: true)
+    public static let modifiedDesceding = FileObjectSorting(type: .modifiedDate, ascending: false)
+    public static let createdAscending = FileObjectSorting(type: .creationDate, ascending: true)
+    public static let createdDesceding = FileObjectSorting(type: .creationDate, ascending: false)
+    
+    /// Initializes a `FileObjectSorting` allows to sort an `Array` of `FileObject`.
+    ///
+    /// - Parameters:
+    ///   - type: Determines to sort based on which file property.
+    ///   - ascending: `true` of resulting `Array` is ascending
+    ///   - isDirectoriesFirst: Puts directoris on the top of resulting `Array`.
+    public init (type: SortType, ascending: Bool = true, isDirectoriesFirst: Bool = false) {
+        self.sortType = type
+        self.ascending = ascending
+        self.isDirectoriesFirst = isDirectoriesFirst
+    }
+    
+    /// Sorts array of `FileObject`s by criterias set in attributes.
+    public func sort(_ files: [FileObject]) -> [FileObject] {
+        return files.sorted {
+            if isDirectoriesFirst {
+                if ($0.isDirectory) && !($1.isDirectory) {
+                    return true
+                }
+                if !($0.isDirectory) && ($1.isDirectory) {
+                    return false
+                }
+            }
+            switch sortType {
+            case .name:
+                return ($0.name).localizedStandardCompare($1.name) == (ascending ? .orderedAscending : .orderedDescending)
+            case .nameCaseSensitive:
+                return ($0.name).localizedCompare($1.name) == (ascending ? .orderedAscending : .orderedDescending)
+            case .nameCaseInsensitive:
+                return ($0.name).localizedCaseInsensitiveCompare($1.name) == (ascending ? .orderedAscending : .orderedDescending)
+            case .extension:
+                let kind1 = $0.isDirectory ? "folder" : ($0.path as NSString).pathExtension
+                let kind2 = $1.isDirectory ? "folder" : ($1.path as NSString).pathExtension
+                return kind1.localizedCaseInsensitiveCompare(kind2) == (ascending ? .orderedAscending : .orderedDescending)
+            case .modifiedDate:
+                let fileMod1 = $0.modifiedDate ?? Date.distantPast
+                let fileMod2 = $1.modifiedDate ?? Date.distantPast
+                return ascending ? fileMod1 < fileMod2 : fileMod1 > fileMod2
+            case .creationDate:
+                let fileCreation1 = $0.creationDate ?? Date.distantPast
+                let fileCreation2 = $1.creationDate ?? Date.distantPast
+                return ascending ? fileCreation1 < fileCreation2 : fileCreation1 > fileCreation2
+            case .size:
+                return ascending ? $0.size < $1.size : $0.size > $1.size
+            }
+        }
+    }
+}
@@ -5,6 +5,9 @@
 //  Created by Amir Abbas Mousavian on 5/6/95.
 //
 //
+
+#import <TargetConditionals.h>
+
 #if TARGET_OS_IPHONE || TARGET_IPHONE_SIMULATOR
 #import <UIKit/UIKit.h>
 //! Project version number for FileProvider iOS.
@@ -0,0 +1,302 @@
+//
+//  FileProviderExtensions.swift
+//  FileProvider
+//
+//  Created by Amir Abbas on 12/27/1395 AP.
+//
+//
+
+import Foundation
+
+public extension Array where Element: FileObject {
+    /// Returns a sorted array of `FileObject`s by criterias set in attributes.
+    public func sort(by type: FileObjectSorting.SortType, ascending: Bool = true, isDirectoriesFirst: Bool = false) -> [Element] {
+        let sorting = FileObjectSorting(type: type, ascending: ascending, isDirectoriesFirst: isDirectoriesFirst)
+        return sorting.sort(self) as! [Element]
+    }
+    
+    /// Sorts array of `FileObject`s by criterias set in attributes.
+    public mutating func sorted(by type: FileObjectSorting.SortType, ascending: Bool = true, isDirectoriesFirst: Bool = false) {
+        self = self.sort(by: type, ascending: ascending, isDirectoriesFirst: isDirectoriesFirst)
+    }
+}
+
+public extension URLFileResourceType {
+    /// **FileProvider** returns corresponding `URLFileResourceType` of a `FileAttributeType` value
+    public init(fileTypeValue: FileAttributeType) {
+        switch fileTypeValue {
+        case FileAttributeType.typeCharacterSpecial: self = .characterSpecial
+        case FileAttributeType.typeDirectory: self = .directory
+        case FileAttributeType.typeBlockSpecial: self = .blockSpecial
+        case FileAttributeType.typeRegular: self = .regular
+        case FileAttributeType.typeSymbolicLink: self = .symbolicLink
+        case FileAttributeType.typeSocket: self = .socket
+        case FileAttributeType.typeUnknown: self = .unknown
+        default: self = .unknown
+        }
+    }
+}
+
+public extension URLResourceKey {
+    /// **FileProvider** returns url of file object.
+    public static let fileURLKey = URLResourceKey(rawValue: "NSURLFileURLKey")
+    /// **FileProvider** returns modification date of file in server
+    public static let serverDateKey = URLResourceKey(rawValue: "NSURLServerDateKey")
+    /// **FileProvider** returns HTTP ETag string of remote resource
+    public static let entryTagKey = URLResourceKey(rawValue: "NSURLEntryTagKey")
+    /// **FileProvider** returns MIME type of file, if returned by server
+    public static let mimeTypeKey = URLResourceKey(rawValue: "NSURLMIMETypeIdentifierKey")
+    /// **FileProvider** returns either file is encrypted or not
+    public static let isEncryptedKey = URLResourceKey(rawValue: "NSURLIsEncryptedKey")
+}
+
+public extension ProgressUserInfoKey {
+    /// **FileProvider** returns associated `FileProviderOperationType`
+    public static let fileProvderOperationTypeKey = ProgressUserInfoKey("FilesProviderOperationTypeKey")
+    /// **FileProvider** returns start date/time of operation
+    public static let startingTimeKey = ProgressUserInfoKey("NSProgressStartingTimeKey")
+}
+
+internal extension URL {
+    var uw_scheme: String {
+        return self.scheme ?? ""
+    }
+    
+    var fileIsDirectory: Bool {
+        return (try? self.resourceValues(forKeys: [.isDirectoryKey]))?.isDirectory ?? false
+    }
+    
+    var fileSize: Int64 {
+        return Int64((try? self.resourceValues(forKeys: [.fileSizeKey]))?.fileSize ?? -1)
+    }
+    
+    var fileExists: Bool {
+        return self.isFileURL && FileManager.default.fileExists(atPath: self.path)
+    }
+}
+
+internal extension URLRequest {
+    mutating func set(httpAuthentication credential: URLCredential?, with type: HTTPAuthenticationType) {
+        func base64(_ str: String) -> String {
+            let plainData = str.data(using: .utf8)
+            let base64String = plainData!.base64EncodedString(options: [])
+            return base64String
+        }
+        
+        guard let credential = credential else { return }
+        switch type {
+        case .basic:
+            let authStr = "\(credential.user ?? ""):\(credential.password ?? "")"
+            self.setValue("Basic \(authStr)", forHTTPHeaderField: "Authorization")
+        case .digest:
+            // handled by RemoteSessionDelegate
+            break
+        case .oAuth1:
+            if let oauth = credential.password {
+                self.setValue("OAuth \(oauth)", forHTTPHeaderField: "Authorization")
+            }
+        case .oAuth2:
+            if let bearer = credential.password {
+                self.setValue("Bearer \(bearer)", forHTTPHeaderField: "Authorization")
+            }
+        }
+    }
+    
+    mutating func set(rangeWithOffset offset: Int64, length: Int) {
+        if length > 0 {
+            self.setValue("bytes=\(offset)-\(offset + Int64(length) - 1)", forHTTPHeaderField: "Range")
+        } else if offset > 0 && length < 0 {
+            self.setValue("bytes=\(offset)-", forHTTPHeaderField: "Range")
+        }
+    }
+    
+    enum ContentType: String {
+        case json = "application/json"
+        case stream = "application/octet-stream"
+        case xml = "text/xml; charset=\"utf-8\""
+    }
+    
+    mutating func set(contentType: ContentType) {
+        self.setValue(contentType.rawValue, forHTTPHeaderField: "Content-Type")
+    }
+    
+    private func asciiEscape(string:String) -> String {
+        var res = ""
+        for char in string.unicodeScalars {
+            let substring = String(char)
+            if substring.canBeConverted(to: .ascii) {
+                res.append(substring)
+            } else {
+                res = res.appendingFormat("\\u%04x", char.value)
+            }
+        }
+        return res
+    }
+    
+    mutating func set(dropboxArgKey requestDictionary: [String: AnyObject]) {
+        guard let jsonData = try? JSONSerialization.data(withJSONObject: requestDictionary, options: []) else {
+            return
+        }
+        guard var jsonString = String(data: jsonData, encoding: .utf8) else { return }
+        jsonString = self.asciiEscape(string: jsonString)
+        jsonString = jsonString.replacingOccurrences(of: "\\/", with: "/")
+        
+        self.setValue(jsonString, forHTTPHeaderField: "Dropbox-API-Arg")
+    }
+}
+
+internal extension Data {
+    internal var isPDF: Bool {
+        return self.count > 4 && self.scanString(length: 4, using: .ascii) == "%PDF"
+    }
+    
+    init? (jsonDictionary dictionary: [String: AnyObject]) {
+        guard let data = try? JSONSerialization.data(withJSONObject: dictionary, options: []) else {
+            return nil
+        }
+        self = data
+    }
+    
+    func deserializeJSON() -> [String: AnyObject]? {
+        if let dic = try? JSONSerialization.jsonObject(with: self, options: []) as? [String: AnyObject] {
+            return dic
+        }
+        return nil
+    }
+    
+    init<T>(value: T) {
+        var value = value
+        self = Data(buffer: UnsafeBufferPointer(start: &value, count: 1))
+    }
+    
+    func scanValue<T>() -> T? {
+        guard MemoryLayout<T>.size <= self.count else { return nil }
+        return self.withUnsafeBytes { $0.pointee }
+    }
+    
+    func scanValue<T>(start: Int) -> T? {
+        let length = MemoryLayout<T>.size
+        guard self.count >= start + length else { return nil }
+        return self.subdata(in: start..<start+length).withUnsafeBytes { $0.pointee }
+    }
+    
+    func scanString(start: Int = 0, length: Int, using encoding: String.Encoding = .utf8) -> String? {
+        guard self.count >= start + length else { return nil }
+        return String(data: self.subdata(in: start..<start+length), encoding: encoding)
+    }
+    
+    static func mapMemory<T, U>(from: T) -> U? {
+        guard MemoryLayout<T>.size >= MemoryLayout<U>.size else { return nil }
+        let data = Data(value: from)
+        return data.scanValue()
+    }
+}
+
+internal extension String {
+    init? (jsonDictionary: [String: AnyObject]) {
+        guard let data = Data(jsonDictionary: jsonDictionary) else {
+            return nil
+        }
+        self.init(data: data, encoding: .utf8)
+    }
+    
+    func deserializeJSON(using encoding: String.Encoding = .utf8) -> [String: AnyObject]? {
+        guard let data = self.data(using: encoding) else {
+            return nil
+        }
+        return data.deserializeJSON()
+    }
+}
+
+internal extension TimeInterval {
+    internal var formatshort: String {
+        var result = "0:00"
+        if self < TimeInterval(Int32.max) {
+            result = ""
+            var time = DateComponents()
+            time.hour   = Int(self / 3600)
+            time.minute = Int((self.truncatingRemainder(dividingBy: 3600)) / 60)
+            time.second = Int(self.truncatingRemainder(dividingBy: 60))
+            let formatter = NumberFormatter()
+            formatter.paddingCharacter = "0"
+            formatter.minimumIntegerDigits = 2
+            formatter.maximumFractionDigits = 0
+            let formatterFirst = NumberFormatter()
+            formatterFirst.maximumFractionDigits = 0
+            if time.hour! > 0 {
+                result = "\(formatterFirst.string(from: NSNumber(value: time.hour!))!):\(formatter.string(from: NSNumber(value: time.minute!))!):\(formatter.string(from: NSNumber(value: time.second!))!)"
+            } else {
+                result = "\(formatterFirst.string(from: NSNumber(value: time.minute!))!):\(formatter.string(from: NSNumber(value: time.second!))!)"
+            }
+        }
+        result = result.trimmingCharacters(in: CharacterSet(charactersIn: ": "))
+        return result
+    }
+}
+
+internal extension Date {
+   init?(rfcString: String) {
+        let dateFor: DateFormatter = DateFormatter()
+        dateFor.locale = Locale(identifier: "en_US")
+        dateFor.dateFormat = "yyyy'-'MM'-'dd'T'HH':'mm':'ssZ"
+        if let rfc3339 = dateFor.date(from: rfcString) {
+            self = rfc3339
+            return
+        }
+        dateFor.dateFormat = "EEE',' dd' 'MMM' 'yyyy HH':'mm':'ss z"
+        if let rfc1123 = dateFor.date(from: rfcString) {
+            self = rfc1123
+             return
+        }
+        dateFor.dateFormat = "EEEE',' dd'-'MMM'-'yy HH':'mm':'ss z"
+        if let rfc850 = dateFor.date(from: rfcString) {
+            self = rfc850
+             return
+        }
+        dateFor.dateFormat = "EEE MMM d HH':'mm':'ss yyyy"
+        if let asctime = dateFor.date(from: rfcString) {
+            self = asctime
+             return
+        }
+        
+        return nil
+    }
+    
+    internal func rfc3339utc() -> String {
+        let fm = DateFormatter()
+        fm.dateFormat = "yyyy'-'MM'-'dd'T'HH':'mm':'ss'Z'"
+        fm.timeZone = TimeZone(identifier: "UTC")
+        fm.locale = Locale(identifier: "en_US_POSIX")
+        return fm.string(from: self)
+    }
+}
+
+internal extension NSPredicate {
+    func findValue(forKey key: String?, operator op: NSComparisonPredicate.Operator? = nil) -> Any? {
+        let val = findAllValues(forKey: key).lazy.filter { (op == nil || $0.operator == op!) && !$0.not }
+        return val.first?.value
+    }
+    
+    func findAllValues(forKey key: String?) -> [(value: Any, operator: NSComparisonPredicate.Operator, not: Bool)] {
+        if let cQuery = self as? NSCompoundPredicate {
+            let find = cQuery.subpredicates.flatMap { ($0 as! NSPredicate).findAllValues(forKey: key) }
+            if cQuery.compoundPredicateType == .not {
+                return find.map { return ($0.value, $0.operator, !$0.not) }
+            }
+            return find
+        } else if let cQuery = self as? NSComparisonPredicate {
+            if cQuery.leftExpression.expressionType == .keyPath, key == nil || cQuery.leftExpression.keyPath == key!, let const = cQuery.rightExpression.constantValue {
+                return [(value: const, operator: cQuery.predicateOperatorType, false)]
+            }
+            if cQuery.rightExpression.expressionType == .keyPath, key == nil || cQuery.rightExpression.keyPath == key!, let const = cQuery.leftExpression.constantValue {
+                return [(value: const, operator: cQuery.predicateOperatorType, false)]
+            }
+            return []
+        } else {
+            return []
+        }
+    }
+}
+
+extension URLError.Code: FoundationErrorEnum {}
+extension CocoaError.Code: FoundationErrorEnum {}
@@ -0,0 +1,393 @@
+//
+//  HTTPFileProvider.swift
+//  FilesProvider
+//
+//  Created by Amir Abbas Mousavian.
+//  Copyright © 2017 Mousavian. Distributed under MIT license.
+//
+
+import Foundation
+
+/**
+ Allows accessing to Dropbox stored files. This provider doesn't cache or save files internally, however you can
+ set `useCache` and `cache` properties to use Foundation `NSURLCache` system.
+ 
+ - Note: Uploading files and data are limited to 150MB, for now.
+ */
+open class HTTPFileProvider: FileProviderBasicRemote, FileProviderOperations, FileProviderReadWrite {
+    open class var type: String { fatalError("HTTPFileProvider is an abstract class. Please implement \(#function) in subclass.") }
+    open let baseURL: URL?
+    open var currentPath: String
+    
+    open var dispatch_queue: DispatchQueue
+    open var operation_queue: OperationQueue {
+        willSet {
+            assert(_session == nil, "It's not effective to change dispatch_queue property after session is initialized.")
+        }
+    }
+    
+    open weak var delegate: FileProviderDelegate?
+    open var credential: URLCredential? {
+        didSet {
+            sessionDelegate?.credential = self.credential
+        }
+    }
+    open private(set) var cache: URLCache?
+    public var useCache: Bool
+    public var validatingCache: Bool
+    
+    fileprivate var _session: URLSession?
+    internal fileprivate(set) var sessionDelegate: SessionDelegate?
+    public var session: URLSession {
+        get {
+            if _session == nil {
+                self.sessionDelegate = SessionDelegate(fileProvider: self)
+                let config = URLSessionConfiguration.default
+                config.urlCache = cache
+                config.requestCachePolicy = .returnCacheDataElseLoad
+                _session = URLSession(configuration: config, delegate: sessionDelegate as URLSessionDelegate?, delegateQueue: self.operation_queue)
+                _session!.sessionDescription = UUID().uuidString
+                initEmptySessionHandler(_session!.sessionDescription!)
+            }
+            return _session!
+        }
+        
+        set {
+            assert(newValue.delegate is SessionDelegate, "session instances should have a SessionDelegate instance as delegate.")
+            _session = newValue
+            if session.sessionDescription?.isEmpty ?? true {
+                _session?.sessionDescription = UUID().uuidString
+            }
+            self.sessionDelegate = newValue.delegate as? SessionDelegate
+            initEmptySessionHandler(_session!.sessionDescription!)
+        }
+    }
+    
+    fileprivate var _longpollSession: URLSession?
+    internal var longpollSession: URLSession {
+        if _longpollSession == nil {
+            let config = URLSessionConfiguration.default
+            config.timeoutIntervalForRequest = 600
+            _longpollSession = URLSession(configuration: config, delegate: nil, delegateQueue: nil)
+        }
+        return _longpollSession!
+    }
+    
+    public init(baseURL: URL?, credential: URLCredential?, cache: URLCache?) {
+        self.baseURL = baseURL
+        self.currentPath = ""
+        self.useCache = false
+        self.validatingCache = true
+        self.cache = cache
+        self.credential = credential
+        
+        #if swift(>=3.1)
+            let queueLabel = "FileProvider.\(Swift.type(of: self).type)"
+        #else
+            let queueLabel = "FileProvider.\(type(of: self).type)"
+        #endif
+        dispatch_queue = DispatchQueue(label: queueLabel, attributes: .concurrent)
+        operation_queue = OperationQueue()
+        operation_queue.name = "\(queueLabel).Operation"
+    }
+    
+    public required convenience init?(coder aDecoder: NSCoder) {
+        fatalError("HTTPFileProvider is an abstract class. Please implement \(#function) in subclass.")
+    }
+    
+    public func encode(with aCoder: NSCoder) {
+        aCoder.encode(self.baseURL, forKey: "baseURL")
+        aCoder.encode(self.credential, forKey: "credential")
+        aCoder.encode(self.currentPath, forKey: "currentPath")
+        aCoder.encode(self.useCache, forKey: "useCache")
+        aCoder.encode(self.validatingCache, forKey: "validatingCache")
+    }
+    
+    public static var supportsSecureCoding: Bool {
+        return true
+    }
+    
+    open func copy(with zone: NSZone? = nil) -> Any {
+        fatalError("HTTPFileProvider is an abstract class. Please implement \(#function) in subclass.")
+    }
+    
+    deinit {
+        if let sessionuuid = _session?.sessionDescription {
+            removeSessionHandler(for: sessionuuid)
+        }
+        
+        if fileProviderCancelTasksOnInvalidating {
+            _session?.invalidateAndCancel()
+        } else {
+            _session?.finishTasksAndInvalidate()
+        }
+    }
+    
+    open func contentsOfDirectory(path: String, completionHandler: @escaping ((_ contents: [FileObject], _ error: Error?) -> Void)) {
+        fatalError("HTTPFileProvider is an abstract class. Please implement \(#function) in subclass.")
+    }
+    
+    open func attributesOfItem(path: String, completionHandler: @escaping ((_ attributes: FileObject?, _ error: Error?) -> Void)) {
+        fatalError("HTTPFileProvider is an abstract class. Please implement \(#function) in subclass.")
+    }
+    
+    open func storageProperties(completionHandler: @escaping ((_ total: Int64, _ used: Int64) -> Void)) {
+        fatalError("HTTPFileProvider is an abstract class. Please implement \(#function) in subclass.")
+    }
+    
+    open func searchFiles(path: String, recursive: Bool, query: NSPredicate, foundItemHandler: ((FileObject) -> Void)?, completionHandler: @escaping ((_ files: [FileObject], _ error: Error?) -> Void)) -> Progress? {
+        fatalError("HTTPFileProvider is an abstract class. Please implement \(#function) in subclass.")
+    }
+    
+    open func isReachable(completionHandler: @escaping (Bool) -> Void) {
+        self.storageProperties { total, _ in
+            completionHandler(total > 0)
+        }
+    }
+    
+    open weak var fileOperationDelegate: FileOperationDelegate?
+    
+    open func create(folder folderName: String, at atPath: String, completionHandler: SimpleCompletionHandler) -> Progress? {
+        let path = (atPath as NSString).appendingPathComponent(folderName) + "/"
+        return doOperation(.create(path: path), completionHandler: completionHandler)
+    }
+    
+    open func moveItem(path: String, to toPath: String, overwrite: Bool, completionHandler: SimpleCompletionHandler) -> Progress? {
+        return doOperation(.move(source: path, destination: toPath), completionHandler: completionHandler)
+    }
+    
+    open func copyItem(path: String, to toPath: String, overwrite: Bool, completionHandler: SimpleCompletionHandler) -> Progress? {
+        return doOperation(.copy(source: path, destination: toPath), completionHandler: completionHandler)
+    }
+    
+    open func removeItem(path: String, completionHandler: SimpleCompletionHandler) -> Progress? {
+        return doOperation(.remove(path: path), completionHandler: completionHandler)
+    }
+    
+    internal func request(for operation: FileOperationType, overwrite: Bool = false, attributes: [URLResourceKey: Any] = [:]) -> URLRequest {
+        fatalError("HTTPFileProvider is an abstract class. Please implement \(#function) in subclass.")
+    }
+    
+    internal func serverError(with code: FileProviderHTTPErrorCode, path: String?, data: Data?) -> FileProviderHTTPError {
+        fatalError("HTTPFileProvider is an abstract class. Please implement \(#function) in subclass.")
+    }
+    
+    internal func multiStatusHandler(source: String, data: Data, completionHandler: SimpleCompletionHandler) -> Void {
+        // WebDAV will override this function
+    }
+    
+    fileprivate func doOperation(_ operation: FileOperationType, completionHandler: SimpleCompletionHandler) -> Progress? {
+        guard fileOperationDelegate?.fileProvider(self, shouldDoOperation: operation) ?? true == true else {
+            return nil
+        }
+        
+        let progress = Progress(totalUnitCount: 1)
+        progress.setUserInfoObject(operation, forKey: .fileProvderOperationTypeKey)
+        progress.kind = .file
+        progress.setUserInfoObject(Progress.FileOperationKind.downloading, forKey: .fileOperationKindKey)
+        
+        let request = self.request(for: operation)
+        
+        let task = session.dataTask(with: request, completionHandler: { (data, response, error) in
+            var serverError: FileProviderHTTPError?
+            if let response = response as? HTTPURLResponse, response.statusCode >= 300, let code = FileProviderHTTPErrorCode(rawValue: response.statusCode) {
+                serverError = self.serverError(with: code, path: operation.source, data: data)
+            }
+            
+            if let response = response as? HTTPURLResponse, FileProviderHTTPErrorCode(rawValue: response.statusCode) == .multiStatus, let data = data {
+                self.multiStatusHandler(source: operation.source, data: data, completionHandler: completionHandler)
+            }
+            
+            if serverError == nil && error == nil {
+                progress.completedUnitCount = 1
+            } else {
+                progress.cancel()
+            }
+            completionHandler?(serverError ?? error)
+            self.delegateNotify(operation, error: serverError ?? error)
+        })
+        task.taskDescription = operation.json
+        progress.cancellationHandler = { [weak task] in
+            task?.cancel()
+        }
+        progress.setUserInfoObject(Date(), forKey: .startingTimeKey)
+        task.resume()
+        return progress
+    }
+    
+    open func copyItem(localFile: URL, to toPath: String, overwrite: Bool, completionHandler: SimpleCompletionHandler) -> Progress? {
+        // check file is not a folder
+        guard (try? localFile.resourceValues(forKeys: [.fileResourceTypeKey]))?.fileResourceType ?? .unknown == .regular else {
+            dispatch_queue.async {
+                completionHandler?(self.throwError(localFile.path, code: URLError.fileIsDirectory))
+            }
+            return nil
+        }
+        
+        let operation = FileOperationType.copy(source: localFile.absoluteString, destination: toPath)
+        guard fileOperationDelegate?.fileProvider(self, shouldDoOperation: operation) ?? true == true else {
+            return nil
+        }
+        let request = self.request(for: operation, overwrite: overwrite)
+        return upload_simple(toPath, request: request, localFile: localFile, operation: operation, completionHandler: completionHandler)
+    }
+    
+    open func copyItem(path: String, toLocalURL destURL: URL, completionHandler: SimpleCompletionHandler) -> Progress? {
+        let operation = FileOperationType.copy(source: path, destination: destURL.absoluteString)
+        let request = self.request(for: operation)
+        return self.download_simple(path: path, request: request, operation: operation, completionHandler: { [weak self] (tempURL, error) in
+            if let error = error {
+                completionHandler?(error)
+                self?.delegateNotify(operation, error: error)
+                return
+            }
+            
+            guard let tempURL = tempURL else {
+                completionHandler?(error)
+                self?.delegateNotify(operation, error: error)
+                return
+            }
+            
+            do {
+                try FileManager.default.moveItem(at: tempURL, to: destURL)
+                completionHandler?(nil)
+                self?.delegateNotify(operation, error: nil)
+            } catch let e {
+                completionHandler?(e)
+                self?.delegateNotify(operation, error: e)
+            }
+        })
+    }
+    
+    open func contents(path: String, offset: Int64, length: Int, completionHandler: @escaping ((_ contents: Data?, _ error: Error?) -> Void)) -> Progress? {
+        if length == 0 || offset < 0 {
+            dispatch_queue.async {
+                completionHandler(Data(), nil)
+            }
+            return nil
+        }
+        
+        let operation = FileOperationType.fetch(path: path)
+        var request = self.request(for: operation)
+        request.set(rangeWithOffset: offset, length: length)
+        return self.download_simple(path: path, request: request, operation: operation, completionHandler: { (tempURL, error) in
+            if let error = error {
+                completionHandler(nil, error)
+                return
+            }
+            
+            guard let tempURL = tempURL else {
+                completionHandler(nil, error)
+                return
+            }
+            
+            do {
+                let data = try Data(contentsOf: tempURL)
+                completionHandler(data, nil)
+            } catch let e {
+                completionHandler(nil, e)
+            }
+        })
+    }
+    
+    public func writeContents(path: String, contents data: Data?, atomically: Bool, overwrite: Bool, completionHandler: SimpleCompletionHandler) -> Progress? {
+        let operation = FileOperationType.modify(path: path)
+        guard fileOperationDelegate?.fileProvider(self, shouldDoOperation: operation) ?? true == true else {
+            return nil
+        }
+        let request = self.request(for: operation, overwrite: overwrite, attributes: [.contentModificationDateKey: Date()])
+        return upload_simple(path, request: request, data: data ?? Data(), operation: operation, completionHandler: completionHandler)
+    }
+
+    internal func upload_simple(_ targetPath: String, request: URLRequest, data: Data? = nil, localFile: URL? = nil, operation: FileOperationType, completionHandler: SimpleCompletionHandler) -> Progress? {
+        let size = data?.count ?? Int((try? localFile?.resourceValues(forKeys: [.fileSizeKey]))??.fileSize ?? -1)
+        
+        var progress = Progress(parent: nil, userInfo: nil)
+        progress.setUserInfoObject(operation, forKey: .fileProvderOperationTypeKey)
+        progress.kind = .file
+        progress.setUserInfoObject(Progress.FileOperationKind.downloading, forKey: .fileOperationKindKey)
+        progress.totalUnitCount = Int64(size)
+        
+        let task: URLSessionUploadTask
+        if let data = data {
+            task = session.uploadTask(with: request, from: data)
+        } else if let localFile = localFile {
+            task = session.uploadTask(with: request, fromFile: localFile)
+        } else {
+            return nil
+        }
+        
+        completionHandlersForTasks[session.sessionDescription!]?[task.taskIdentifier] = { [weak self] error in
+            var responseError: FileProviderHTTPError?
+            if let code = (task.response as? HTTPURLResponse)?.statusCode , code >= 300, let rCode = FileProviderHTTPErrorCode(rawValue: code) {
+                // We can't fetch server result from delegate!
+                responseError = self?.serverError(with: rCode, path: targetPath, data: nil)
+            }
+            if !(responseError == nil && error == nil) {
+                progress.cancel()
+            }
+            completionHandler?(responseError ?? error)
+            self?.delegateNotify(operation, error: responseError ?? error)
+        }
+        task.taskDescription = operation.json
+        task.addObserver(sessionDelegate!, forKeyPath: #keyPath(URLSessionTask.countOfBytesSent), options: .new, context: &progress)
+        progress.cancellationHandler = { [weak task] in
+            task?.cancel()
+        }
+        progress.setUserInfoObject(Date(), forKey: .startingTimeKey)
+        task.resume()
+        return progress
+    }
+    
+    internal func download_simple(path: String, request: URLRequest, operation: FileOperationType, completionHandler: @escaping ((_ tempURL: URL?, _ error: Error?) -> Void)) -> Progress? {
+        var progress = Progress(parent: nil, userInfo: nil)
+        progress.setUserInfoObject(operation, forKey: .fileProvderOperationTypeKey)
+        progress.kind = .file
+        progress.setUserInfoObject(Progress.FileOperationKind.downloading, forKey: .fileOperationKindKey)
+        
+        let task = session.downloadTask(with: request)
+        completionHandlersForTasks[session.sessionDescription!]?[task.taskIdentifier] = { error in
+            if error != nil {
+                progress.cancel()
+            }
+            completionHandler(nil, error)
+        }
+        downloadCompletionHandlersForTasks[session.sessionDescription!]?[task.taskIdentifier] = { tempURL in
+            guard let httpResponse = task.response as? HTTPURLResponse , httpResponse.statusCode < 300 else {
+                let code = FileProviderHTTPErrorCode(rawValue: (task.response as? HTTPURLResponse)?.statusCode ?? -1)
+                let errorData : Data? = nil //Data(contentsOf:cacheURL) // TODO: Figure out how to get error response data for the error description
+                let serverError : FileProviderHTTPError? = code != nil ? self.serverError(with: code!, path: path, data: errorData) : nil
+                if serverError != nil {
+                    progress.cancel()
+                }
+                completionHandler(nil, serverError)
+                return
+            }
+            
+            completionHandler(tempURL, nil)
+        }
+        task.taskDescription = operation.json
+        task.addObserver(sessionDelegate!, forKeyPath: #keyPath(URLSessionTask.countOfBytesReceived), options: .new, context: &progress)
+        task.addObserver(sessionDelegate!, forKeyPath: #keyPath(URLSessionTask.countOfBytesExpectedToReceive), options: .new, context: &progress)
+        progress.cancellationHandler = { [weak task] in
+            task?.cancel()
+        }
+        progress.setUserInfoObject(Date(), forKey: .startingTimeKey)
+        task.resume()
+        return progress
+    }
+}
+
+extension HTTPFileProvider {
+    internal func delegateNotify(_ operation: FileOperationType, error: Error?) {
+        DispatchQueue.main.async(execute: {
+            if error == nil {
+                self.delegate?.fileproviderSucceed(self, operation: operation)
+            } else {
+                self.delegate?.fileproviderFailed(self, operation: operation)
+            }
+        })
+    }
+}
+
+extension HTTPFileProvider: FileProvider { }
@@ -0,0 +1,230 @@
+//
+//  LocalFileProvider.swift
+//  FileProvider
+//
+//  Created by Amir Abbas Mousavian.
+//  Copyright © 2016 Mousavian. Distributed under MIT license.
+//
+
+import Foundation
+
+/// Containts path, url and attributes of a local file or resource.
+public final class LocalFileObject: FileObject {
+    internal override init(url: URL?, name: String, path: String) {
+        super.init(url: url, name: name, path: path)
+    }
+    
+    /// Initiates a `LocalFileObject` with attributes of file in path.
+    public convenience init? (fileWithPath path: String, relativeTo relativeURL: URL?) {
+        var fileURL: URL?
+        var rpath = path.replacingOccurrences(of: relativeURL?.path ?? "", with: "", options: .anchored)
+        if relativeURL != nil && rpath.hasPrefix("/") {
+            _=rpath.characters.removeFirst()
+        }
+        if #available(iOS 9.0, macOS 10.11, tvOS 9.0, *) {
+            fileURL = URL(fileURLWithPath: rpath, relativeTo: relativeURL)
+        } else {
+            rpath = rpath.addingPercentEncoding(withAllowedCharacters: .urlPathAllowed) ?? rpath
+            fileURL = URL(string: rpath, relativeTo: relativeURL) ?? relativeURL
+        }
+        
+        if let fileURL = fileURL {
+            self.init(fileWithURL: fileURL)
+        } else {
+            return nil
+        }
+    }
+    
+    /// Initiates a `LocalFileObject` with attributes of file in url.
+    public convenience init?(fileWithURL fileURL: URL) {
+        do {
+            let values = try fileURL.resourceValues(forKeys: [.nameKey, .fileSizeKey, .totalFileSizeKey, .fileAllocatedSizeKey, .totalFileAllocatedSizeKey, .creationDateKey, .contentModificationDateKey, .fileResourceTypeKey, .isHiddenKey, .isWritableKey, .typeIdentifierKey, .generationIdentifierKey, .documentIdentifierKey])
+            let path = fileURL.relativePath.hasPrefix("/") ? fileURL.relativePath : "/" + fileURL.relativePath
+            
+            self.init(url: fileURL, name: values.name ?? fileURL.lastPathComponent, path: path)
+            for (key, value) in values.allValues {
+                self.allValues[key] = value
+            }
+        } catch {
+            return nil
+        }
+    }
+    
+    /// The total size allocated on disk for the file
+    open internal(set) var allocatedSize: Int64 {
+        get {
+            return allValues[.fileAllocatedSizeKey] as? Int64 ?? 0
+        }
+        set {
+            allValues[.fileAllocatedSizeKey] = Int(exactly: newValue) ?? Int.max
+        }
+    }
+    
+    /// The document identifier is a value assigned by the kernel/system to a file or directory. 
+    /// This value is used to identify the document regardless of where it is moved on a volume. 
+    /// The identifier persists across system restarts.
+    open internal(set) var id: Int? {
+        get {
+            return allValues[.documentIdentifierKey] as? Int
+        }
+        set {
+            allValues[.documentIdentifierKey] = newValue
+        }
+    }
+    
+    /// The revision of file, which changes when a file contents are modified. 
+    /// Changes to attributes or other file metadata do not change the identifier.
+    open var rev: String? {
+        get {
+            let data = allValues[.generationIdentifierKey] as? Data
+            return data?.map { String(format: "%02hhx", $0) }.joined()
+        }
+    }
+}
+
+internal final class LocalFolderMonitor {
+    fileprivate let source: DispatchSourceFileSystemObject
+    fileprivate let descriptor: CInt
+    fileprivate let qq: DispatchQueue = DispatchQueue.global(qos: .default)
+    fileprivate var state: Bool = false
+    fileprivate var monitoredTime: TimeInterval = Date().timeIntervalSinceReferenceDate
+    var url: URL
+    
+    /// Creates a folder monitor object with monitoring enabled.
+    init(url: URL, handler: @escaping ()->Void) {
+        self.url = url
+        descriptor = open((url as NSURL).fileSystemRepresentation, O_EVTONLY)
+        source = DispatchSource.makeFileSystemObjectSource(fileDescriptor: descriptor, eventMask: .write, queue: qq)
+        // Folder monitoring is recursive and deep. Monitoring a root folder may be very costly
+        // We have a 0.2 second delay to ensure we wont call handler 1000s times when there is
+        // a huge file operation. This ensures app will work smoothly while this 250 milisec won't
+        // affect user experince much
+        let main_handler: ()->Void = { [weak self] in
+            guard let `self` = self else { return }
+            if Date().timeIntervalSinceReferenceDate < self.monitoredTime + 0.2 {
+                return
+            }
+            self.monitoredTime = Date().timeIntervalSinceReferenceDate
+            self.source.suspend()
+            DispatchQueue.main.asyncAfter(deadline: .now() + 0.25, execute: {
+                handler()
+                self.source.resume()
+            })
+        }
+        source.setEventHandler(handler: main_handler)
+        source.setCancelHandler {
+            close(self.descriptor)
+        }
+        start()
+    }
+    
+    /// Starts sending notifications if currently stopped
+    func start() {
+        if !state {
+            state = true
+            source.resume()
+        }
+    }
+    
+    /// Stops sending notifications if currently enabled
+    func stop() {
+        if state {
+            state = false
+            source.suspend()
+        }
+    }
+    
+    deinit {
+        source.cancel()
+    }
+}
+
+internal class LocalFileProviderManagerDelegate: NSObject, FileManagerDelegate {
+    weak var provider: LocalFileProvider?
+    
+    init(provider: LocalFileProvider) {
+        self.provider = provider
+    }
+    
+    func fileManager(_ fileManager: FileManager, shouldCopyItemAt srcURL: URL, to dstURL: URL) -> Bool {
+        guard let provider = self.provider, let delegate = provider.fileOperationDelegate else {
+            return true
+        }
+        let srcPath = provider.relativePathOf(url: srcURL)
+        let dstPath = provider.relativePathOf(url: dstURL)
+        return delegate.fileProvider(provider, shouldDoOperation: .copy(source: srcPath, destination: dstPath))
+    }
+    
+    func fileManager(_ fileManager: FileManager, shouldMoveItemAt srcURL: URL, to dstURL: URL) -> Bool {
+        guard let provider = self.provider, let delegate = provider.fileOperationDelegate else {
+            return true
+        }
+        let srcPath = provider.relativePathOf(url: srcURL)
+        let dstPath = provider.relativePathOf(url: dstURL)
+        return delegate.fileProvider(provider, shouldDoOperation: .move(source: srcPath, destination: dstPath))
+    }
+    
+    func fileManager(_ fileManager: FileManager, shouldRemoveItemAt URL: URL) -> Bool {
+        guard let provider = self.provider, let delegate = provider.fileOperationDelegate else {
+            return true
+        }
+        let path = provider.relativePathOf(url: URL)
+        return delegate.fileProvider(provider, shouldDoOperation: .remove(path: path))
+    }
+    
+    func fileManager(_ fileManager: FileManager, shouldLinkItemAt srcURL: URL, to dstURL: URL) -> Bool {
+        guard let provider = self.provider, let delegate = provider.fileOperationDelegate else {
+            return true
+        }
+        let srcPath = provider.relativePathOf(url: srcURL)
+        let dstPath = provider.relativePathOf(url: dstURL)
+        return delegate.fileProvider(provider, shouldDoOperation: .link(link: srcPath, target: dstPath))
+    }
+    
+    func fileManager(_ fileManager: FileManager, shouldProceedAfterError error: Error, copyingItemAt srcURL: URL, to dstURL: URL) -> Bool {
+        guard let provider = self.provider, let delegate = provider.fileOperationDelegate else {
+            return false
+        }
+        let srcPath = provider.relativePathOf(url: srcURL)
+        let dstPath = provider.relativePathOf(url: dstURL)
+        return delegate.fileProvider(provider, shouldProceedAfterError: error, operation: .copy(source: srcPath, destination: dstPath))
+    }
+    
+    func fileManager(_ fileManager: FileManager, shouldProceedAfterError error: Error, movingItemAt srcURL: URL, to dstURL: URL) -> Bool {
+        guard let provider = self.provider, let delegate = provider.fileOperationDelegate else {
+            return false
+        }
+        let srcPath = provider.relativePathOf(url: srcURL)
+        let dstPath = provider.relativePathOf(url: dstURL)
+        return delegate.fileProvider(provider, shouldProceedAfterError: error, operation: .move(source: srcPath, destination: dstPath))
+    }
+    
+    func fileManager(_ fileManager: FileManager, shouldProceedAfterError error: Error, removingItemAt URL: URL) -> Bool {
+        guard let provider = self.provider, let delegate = provider.fileOperationDelegate else {
+            return false
+        }
+        let path = provider.relativePathOf(url: URL)
+        return delegate.fileProvider(provider, shouldProceedAfterError: error, operation: .remove(path: path))
+    }
+    
+    func fileManager(_ fileManager: FileManager, shouldProceedAfterError error: Error, linkingItemAt srcURL: URL, to dstURL: URL) -> Bool {
+        guard let provider = self.provider, let delegate = provider.fileOperationDelegate else {
+            return false
+        }
+        let srcPath = provider.relativePathOf(url: srcURL)
+        let dstPath = provider.relativePathOf(url: dstURL)
+        return delegate.fileProvider(provider, shouldProceedAfterError: error, operation: .link(link: srcPath, target: dstPath))
+    }
+}
+
+class UndoBox: NSObject {
+    weak var provider: FileProvideUndoable?
+    let operation: FileOperationType
+    let undoOperation: FileOperationType
+    
+    init(provider: FileProvideUndoable, operation: FileOperationType, undoOperation: FileOperationType) {
+        self.provider = provider
+        self.operation = operation
+        self.undoOperation = undoOperation
+    }
+}
@@ -0,0 +1,336 @@
+
+//
+//  OneDriveFileProvider.swift
+//  FileProvider
+//
+//  Created by Amir Abbas Mousavian.
+//  Copyright © 2017 Mousavian. Distributed under MIT license.
+//
+
+import Foundation
+import CoreGraphics
+
+/**
+ Allows accessing to OneDrive stored files, either hosted on Microsoft servers or business coprporate one.
+ This provider doesn't cache or save files internally, however you can set `useCache` and `cache` properties
+ to use Foundation `NSURLCache` system.
+ 
+ - Note: Uploading files and data are limited to 100MB, for now.
+ */
+open class OneDriveFileProvider: HTTPFileProvider {
+    override open class var type: String { return "OneDrive" }
+    /// Drive name for user, default is `root`. Changing its value will effect on new operations.
+    open var drive: String
+    
+    /**
+     Initializer for Onedrive provider with given client ID and Token.
+     These parameters must be retrieved via [Authentication for the OneDrive API](https://dev.onedrive.com/auth/readme.htm).
+     
+     There are libraries like [p2/OAuth2](https://github.com/p2/OAuth2) or [OAuthSwift](https://github.com/OAuthSwift/OAuthSwift) which can facilate the procedure to retrieve token.
+     The latter is easier to use and prefered. Also you can use [auth0/Lock](https://github.com/auth0/Lock.iOS-OSX) which provides graphical user interface.
+     
+     - Parameters:
+       - credential: a `URLCredential` object with Client ID set as `user` and Token set as `password`.
+       - serverURL: server url, Set it if you are trying to connect OneDrive Business server, otherwise leave it
+         `nil` to connect to OneDrive Personal uses.
+       - drive: drive name for user on server, default value is `root`.
+       - cache: A URLCache to cache downloaded files and contents.
+     */
+    public init(credential: URLCredential?, serverURL: URL? = nil, drive: String = "root", cache: URLCache? = nil) {
+        let baseURL = serverURL?.absoluteURL ?? URL(string: "https://api.onedrive.com/")!
+        let refinedBaseURL = baseURL.absoluteString.hasSuffix("/") ? baseURL : baseURL.appendingPathComponent("")
+        self.drive = drive
+        super.init(baseURL: refinedBaseURL, credential: credential, cache: cache)
+    }
+    
+    public required convenience init?(coder aDecoder: NSCoder) {
+        self.init(credential: aDecoder.decodeObject(forKey: "credential") as? URLCredential,
+                  serverURL: aDecoder.decodeObject(forKey: "baseURL") as? URL,
+                  drive: aDecoder.decodeObject(forKey: "drive") as? String ?? "root")
+        self.currentPath   = aDecoder.decodeObject(forKey: "currentPath") as? String ?? ""
+        self.useCache = aDecoder.decodeBool(forKey: "useCache")
+        self.validatingCache = aDecoder.decodeBool(forKey: "validatingCache")
+    }
+    
+    open override func encode(with aCoder: NSCoder) {
+        super.encode(with: aCoder)
+        aCoder.encode(self.drive, forKey: "drive")
+    }
+    
+    open override func copy(with zone: NSZone? = nil) -> Any {
+        let copy = OneDriveFileProvider(credential: self.credential, serverURL: self.baseURL, drive: self.drive, cache: self.cache)
+        copy.currentPath = self.currentPath
+        copy.delegate = self.delegate
+        copy.fileOperationDelegate = self.fileOperationDelegate
+        copy.useCache = self.useCache
+        copy.validatingCache = self.validatingCache
+        return copy
+    }
+    
+    open override func contentsOfDirectory(path: String, completionHandler: @escaping ((_ contents: [FileObject], _ error: Error?) -> Void)) {
+        list(path) { (contents, cursor, error) in
+            completionHandler(contents, error)
+        }
+    }
+    
+    open override func attributesOfItem(path: String, completionHandler: @escaping ((_ attributes: FileObject?, _ error: Error?) -> Void)) {
+        var request = URLRequest(url: url(of: path))
+        request.httpMethod = "GET"
+        request.set(httpAuthentication: credential, with: .oAuth2)
+        let task = session.dataTask(with: request, completionHandler: { (data, response, error) in
+            var serverError: FileProviderOneDriveError?
+            var fileObject: OneDriveFileObject?
+            if let response = response as? HTTPURLResponse {
+                let code = FileProviderHTTPErrorCode(rawValue: response.statusCode)
+                serverError = code != nil ? FileProviderOneDriveError(code: code!, path: path, errorDescription: String(data: data ?? Data(), encoding: .utf8)) : nil
+                if let json = data?.deserializeJSON(), let file = OneDriveFileObject(baseURL: self.baseURL, drive: self.drive, json: json) {
+                    fileObject = file
+                }
+            }
+            completionHandler(fileObject, serverError ?? error)
+        }) 
+        task.resume()
+    }
+    
+    open override func storageProperties(completionHandler: @escaping ((_ total: Int64, _ used: Int64) -> Void)) {
+        var request = URLRequest(url: url())
+        request.httpMethod = "GET"
+        request.set(httpAuthentication: credential, with: .oAuth2)
+        let task = session.dataTask(with: request, completionHandler: { (data, response, error) in
+            var totalSize: Int64 = -1
+            var usedSize: Int64 = 0
+            if let json = data?.deserializeJSON() {
+                totalSize = (json["total"] as? NSNumber)?.int64Value ?? -1
+                usedSize = (json["used"] as? NSNumber)?.int64Value ?? 0
+            }
+            completionHandler(totalSize, usedSize)
+        }) 
+        task.resume()
+    }
+    
+    open override func searchFiles(path: String, recursive: Bool, query: NSPredicate, foundItemHandler: ((FileObject) -> Void)?, completionHandler: @escaping ((_ files: [FileObject], _ error: Error?) -> Void)) -> Progress? {
+        var foundFiles = [OneDriveFileObject]()
+        var queryStr: String?
+        queryStr = query.findValue(forKey: "name") as? String ?? query.findAllValues(forKey: nil).flatMap { $0.value as? String }.first
+        guard let finalQueryStr = queryStr else { return nil }
+        let progress = Progress(parent: nil, userInfo: nil)
+        progress.setUserInfoObject(url(of: path), forKey: .fileURLKey)
+        search(path, query: finalQueryStr, progress: progress, foundItem: { (file) in
+            if query.evaluate(with: file.mapPredicate()) {
+                foundFiles.append(file)
+                foundItemHandler?(file)
+            }
+        }, completionHandler: { (error) in
+            completionHandler(foundFiles, error)
+        })
+        return progress
+    }
+    
+    open func url(of path: String? = nil, modifier: String? = nil) -> URL {
+        var rpath: String
+        if let path = path {
+            rpath = path
+        } else {
+            rpath = self.currentPath
+        }
+        
+        let driveURL = baseURL!.appendingPathComponent("drive/\(drive):/")
+        
+        if rpath.hasPrefix("/") {
+            _=rpath.characters.removeFirst()
+        }
+        if rpath.isEmpty {
+            if let modifier = modifier {
+                return driveURL.appendingPathComponent(modifier)
+            }
+            return driveURL
+        }
+        
+        rpath = rpath.trimmingCharacters(in: pathTrimSet)
+        if let modifier = modifier {
+            rpath = rpath + ":/" + modifier
+        }
+        
+        return  driveURL.appendingPathComponent(rpath)
+    }
+    
+    open override func isReachable(completionHandler: @escaping (Bool) -> Void) {
+        var request = URLRequest(url: url())
+        request.httpMethod = "HEAD"
+        request.set(httpAuthentication: credential, with: .oAuth2)
+        let task = session.dataTask(with: request, completionHandler: { (data, response, error) in
+            let status = (response as? HTTPURLResponse)?.statusCode ?? 400
+            completionHandler(status == 200)
+        })
+        task.resume()
+    }
+    
+    override func request(for operation: FileOperationType, overwrite: Bool = false, attributes: [URLResourceKey : Any] = [:]) -> URLRequest {
+        let method: String
+        let url: URL
+        switch operation {
+        case .fetch(path: let path):
+            method = "GET"
+            url = self.url(of: path, modifier: "content")
+        case .modify(path: let path):
+            method = "PUT"
+            let queryStr = overwrite ? "" : "?@name.conflictBehavior=fail"
+            url = self.url(of: path, modifier: "content\(queryStr)")
+        case .create(path: let path):
+            method = "CREATE"
+            url = self.url(of: path)
+        case .copy(let source, let dest) where !source.hasPrefix("file://") && !dest.hasPrefix("file://"):
+            method = "POST"
+            url = self.url(of: source)
+        case .copy(let source, let dest) where source.hasPrefix("file://"):
+            method = "PUT"
+            let queryStr = overwrite ? "" : "?@name.conflictBehavior=fail"
+            url = self.url(of: dest, modifier: "content\(queryStr)")
+        case .copy(let source, let dest) where dest.hasPrefix("file://"):
+            method = "GET"
+            url = self.url(of: source, modifier: "content")
+        case .move(source: let source, destination: _):
+            method = "PATCH"
+            url = self.url(of: source)
+        case .remove(path: let path):
+            method = "DELETE"
+            url = self.url(of: path)
+        default: // link
+            fatalError("Unimplemented operation \(operation.description) in \(#file)")
+        }
+        var request = URLRequest(url: url)
+        request.httpMethod = method
+        request.set(httpAuthentication: credential, with: .oAuth2)
+        if let dest = correctPath(operation.destination) as NSString?, !dest.hasPrefix("file://") {
+            request.set(contentType: .json)
+            var requestDictionary = [String: AnyObject]()
+            requestDictionary["parentReference"] = ("/drive/\(drive):" + dest.deletingLastPathComponent) as NSString
+            requestDictionary["name"] = dest.lastPathComponent as NSString
+            request.httpBody = Data(jsonDictionary: requestDictionary)
+        }
+        
+        return request
+    }
+    
+    override func serverError(with code: FileProviderHTTPErrorCode, path: String?, data: Data?) -> FileProviderHTTPError {
+        return FileProviderOneDriveError(code: code, path: path ?? "", errorDescription:  data.flatMap({ String(data: $0, encoding: .utf8) }))
+    }
+    
+    override func upload_simple(_ targetPath: String, request: URLRequest, data: Data?, localFile: URL?, operation: FileOperationType, completionHandler: SimpleCompletionHandler) -> Progress? {
+        let size = data?.count ?? Int((try? localFile?.resourceValues(forKeys: [.fileSizeKey]))??.fileSize ?? -1)
+        if size > 100 * 1024 * 1024 {
+            let error = FileProviderOneDriveError(code: .payloadTooLarge, path: targetPath, errorDescription: nil)
+            completionHandler?(error)
+            self.delegateNotify(operation, error: error)
+            return nil
+        }
+        
+        return super.upload_simple(targetPath, request: request, data: data, localFile: localFile, operation: operation, completionHandler: completionHandler)
+    }
+}
+
+extension OneDriveFileProvider {
+    fileprivate func registerNotifcation(path: String, eventHandler: (() -> Void)) {
+        /* There is two ways to monitor folders changing in OneDrive. Either using webooks
+         * which means you have to implement a server to translate it to push notifications
+         * or using apiv2 list_folder/longpoll method. The second one is implemeted here.
+         * Tough webhooks are much more efficient, longpoll is much simpler to implement!
+         * You can implemnt your own webhook service and replace this method accordingly.
+         */
+        NotImplemented()
+    }
+    fileprivate func unregisterNotifcation(path: String) {
+        NotImplemented()
+    }
+}
+
+extension OneDriveFileProvider: FileProviderSharing {
+    open func publicLink(to path: String, completionHandler: @escaping ((_ link: URL?, _ attribute: FileObject?, _ expiration: Date?, _ error: Error?) -> Void)) {
+        var request = URLRequest(url: self.url(of: path, modifier: "action.createLink"))
+        request.httpMethod = "POST"
+        let requestDictionary: [String: AnyObject] = ["type": "view" as NSString]
+        request.httpBody = Data(jsonDictionary: requestDictionary)
+        let task = session.dataTask(with: request, completionHandler: { (data, response, error) in
+            var serverError: FileProviderOneDriveError?
+            var link: URL?
+            if let response = response as? HTTPURLResponse {
+                let code = FileProviderHTTPErrorCode(rawValue: response.statusCode)
+                serverError = code != nil ? FileProviderOneDriveError(code: code!, path: path, errorDescription: String(data: data ?? Data(), encoding: .utf8)) : nil
+                if let json = data?.deserializeJSON() {
+                    if let linkDic = json["link"] as? NSDictionary, let linkStr = linkDic["webUrl"] as? String {
+                        link = URL(string: linkStr)
+                    }
+                }
+            }
+            
+            completionHandler(link, nil, nil, serverError ?? error)
+        })
+        task.resume()
+    }
+}
+
+
+extension OneDriveFileProvider: ExtendedFileProvider {
+    open func thumbnailOfFileSupported(path: String) -> Bool {
+        return true
+    }
+    
+    open func propertiesOfFileSupported(path: String) -> Bool {
+        let fileExt = (path as NSString).pathExtension.lowercased()
+        switch fileExt {
+        case "jpg", "jpeg", "bmp", "gif", "png", "tif", "tiff":
+            return true
+        case "mp3", "aac", "m4a", "wma":
+            return true
+        case "mp4", "mpg", "3gp", "mov", "avi", "wmv":
+            return true
+        default:
+            return false
+        }
+    }
+    
+    open func thumbnailOfFile(path: String, dimension: CGSize?, completionHandler: @escaping ((_ image: ImageClass?, _ error: Error?) -> Void)) {
+        let url: URL
+        if let dimension = dimension {
+            url = self.url(of: path, modifier: "thumbnails/0/=c\(dimension.width)x\(dimension.height)/content")
+        } else {
+            url =  self.url(of: path, modifier: "thumbnails/0/small/content")
+        }
+        
+        var request = URLRequest(url: url)
+        request.set(httpAuthentication: credential, with: .oAuth2)
+        let task = self.session.dataTask(with: request, completionHandler: { (data, response, error) in
+            var image: ImageClass? = nil
+            if let code = (response as? HTTPURLResponse)?.statusCode , code >= 300, let rCode = FileProviderHTTPErrorCode(rawValue: code) {
+                let responseError = FileProviderOneDriveError(code: rCode, path: path, errorDescription: String(data: data ?? Data(), encoding: .utf8))
+                completionHandler(nil, responseError)
+                return
+            }
+            if let data = data {
+                image = ImageClass(data: data)
+            }
+            completionHandler(image, error)
+        })
+        task.resume()
+    }
+    
+    open func propertiesOfFile(path: String, completionHandler: @escaping ((_ propertiesDictionary: [String : Any], _ keys: [String], _ error: Error?) -> Void)) {
+        var request = URLRequest(url: url(of: path))
+        request.httpMethod = "GET"
+        request.set(httpAuthentication: credential, with: .oAuth2)
+        let task = session.dataTask(with: request, completionHandler: { (data, response, error) in
+            var serverError: FileProviderOneDriveError?
+            var dic = [String: Any]()
+            var keys = [String]()
+            if let response = response as? HTTPURLResponse {
+                let code = FileProviderHTTPErrorCode(rawValue: response.statusCode)
+                serverError = code != nil ? FileProviderOneDriveError(code: code!, path: path, errorDescription: String(data: data ?? Data(), encoding: .utf8)) : nil
+                if let json = data?.deserializeJSON() {
+                    (dic, keys) = self.mapMediaInfo(json)
+                }
+            }
+            completionHandler(dic, keys, serverError ?? error)
+        })
+        task.resume()
+    }
+}
@@ -0,0 +1,233 @@
+//
+//  OneDriveHelper.swift
+//  FileProvider
+//
+//  Created by Amir Abbas Mousavian.
+//  Copyright © 2017 Mousavian. Distributed under MIT license.
+//
+
+import Foundation
+
+/// Error returned by OneDrive server when trying to access or do operations on a file or folder.
+public struct FileProviderOneDriveError: FileProviderHTTPError {
+    public let code: FileProviderHTTPErrorCode
+    public let path: String
+    public let errorDescription: String?
+}
+
+/// Containts path, url and attributes of a OneDrive file or resource.
+public final class OneDriveFileObject: FileObject {
+    internal init(baseURL: URL?, name: String, path: String) {
+        var rpath = (URL(string:path)?.appendingPathComponent(name).absoluteString)!
+        if rpath.hasPrefix("/") {
+            _=rpath.characters.removeFirst()
+        }
+        let url = URL(string: rpath, relativeTo: baseURL) ?? URL(string: rpath)!
+        
+        super.init(url: url, name: name, path: rpath.removingPercentEncoding ?? path)
+    }
+    
+    internal convenience init? (baseURL: URL?, drive: String, jsonStr: String) {
+        guard let json = jsonStr.deserializeJSON() else { return nil }
+        self.init(baseURL: baseURL, drive: drive, json: json)
+    }
+    
+    internal convenience init? (baseURL: URL?, drive: String, json: [String: AnyObject]) {
+        guard let name = json["name"] as? String else { return nil }
+        guard let path = (json["parentReference"] as? NSDictionary)?["path"] as? String else { return nil }
+        var lPath = path.replacingOccurrences(of: "/drive/\(drive):", with: "/", options: .anchored, range: nil)
+        lPath = lPath.replacingOccurrences(of: "/:", with: "", options: .anchored)
+        lPath = lPath.replacingOccurrences(of: "//", with: "", options: .anchored)
+        self.init(baseURL: baseURL, name: name, path: lPath)
+        self.size = (json["size"] as? NSNumber)?.int64Value ?? -1
+        self.modifiedDate = Date(rfcString: json["lastModifiedDateTime"] as? String ?? "")
+        self.creationDate = Date(rfcString: json["createdDateTime"] as? String ?? "")
+        self.type = json["folder"] != nil ? .directory : .regular
+        self.id = json["id"] as? String
+        self.entryTag = json["eTag"] as? String
+    }
+    
+    /// The document identifier is a value assigned by the OneDrive to a file.
+    /// This value is used to identify the document regardless of where it is moved on a volume.
+    /// The identifier persists across system restarts.
+    open internal(set) var id: String? {
+        get {
+            return allValues[.documentIdentifierKey] as? String
+        }
+        set {
+            allValues[.documentIdentifierKey] = newValue
+        }
+    }
+    
+    /// MIME type of file contents returned by OneDrive server.
+    open internal(set) var contentType: String {
+        get {
+            return allValues[.mimeTypeKey] as? String ?? ""
+        }
+        set {
+            allValues[.mimeTypeKey] = newValue
+        }
+    }
+    
+    /// HTTP E-Tag, can be used to mark changed files.
+    open internal(set) var entryTag: String? {
+        get {
+            return allValues[.entryTagKey] as? String
+        }
+        set {
+            allValues[.entryTagKey] = newValue
+        }
+    }
+}
+
+// codebeat:disable[ARITY]
+internal extension OneDriveFileProvider {
+    func list(_ path: String, cursor: URL? = nil, prevContents: [OneDriveFileObject] = [], completionHandler: @escaping ((_ contents: [FileObject], _ cursor: String?, _ error: Error?) -> Void)) {
+        let url = cursor ?? self.url(of: path, modifier: "children")
+        var request = URLRequest(url: url)
+        request.httpMethod = "GET"
+        request.set(httpAuthentication: credential, with: .oAuth2)
+        let task = session.dataTask(with: request, completionHandler: { (data, response, error) in
+            var responseError: FileProviderOneDriveError?
+            var files = prevContents
+            if let code = (response as? HTTPURLResponse)?.statusCode , code >= 300, let rCode = FileProviderHTTPErrorCode(rawValue: code) {
+                responseError = FileProviderOneDriveError(code: rCode, path: path, errorDescription: String(data: data ?? Data(), encoding: .utf8))
+            }
+            if let json = data?.deserializeJSON() {
+                if let entries = json["value"] as? [AnyObject] , entries.count > 0 {
+                    for entry in entries {
+                        if let entry = entry as? [String: AnyObject], let file = OneDriveFileObject(baseURL: self.baseURL, drive: self.drive, json: entry) {
+                            files.append(file)
+                        }
+                    }
+                    let ncursor: URL? = (json["@odata.nextLink"] as? String).flatMap { URL(string: $0) }
+                    let hasmore = ncursor != nil
+                    if hasmore {
+                        self.list(path, cursor: ncursor, prevContents: files, completionHandler: completionHandler)
+                        return
+                    }
+                }
+            }
+            completionHandler(files, nil, responseError ?? error)
+        })
+        task.taskDescription = FileOperationType.fetch(path: path).json
+        task.resume()
+    }
+    
+    func search(_ startPath: String = "", query: String, next: URL? = nil, progress: Progress, foundItem: @escaping ((_ file: OneDriveFileObject) -> Void), completionHandler: @escaping ((_ error: Error?) -> Void)) {
+        if progress.isCancelled {
+            return
+        }
+        
+        let url: URL
+        let q = query.addingPercentEncoding(withAllowedCharacters: .urlQueryAllowed)!
+        url = next ?? self.url(of: startPath, modifier: "view.search?q=\(q)")
+        var request = URLRequest(url: url)
+        request.httpMethod = "GET"
+        request.set(httpAuthentication: credential, with: .oAuth2)
+        
+        let task = session.dataTask(with: request, completionHandler: { (data, response, error) in
+            var responseError: FileProviderOneDriveError?
+            if let code = (response as? HTTPURLResponse)?.statusCode , code >= 300, let rCode = FileProviderHTTPErrorCode(rawValue: code) {
+                responseError = FileProviderOneDriveError(code: rCode, path: startPath, errorDescription: String(data: data ?? Data(), encoding: .utf8))
+            }
+            if let json = data?.deserializeJSON() {
+                if let entries = json["value"] as? [AnyObject] , entries.count > 0 {
+                    for entry in entries {
+                        if let entry = entry as? [String: AnyObject], let file = OneDriveFileObject(baseURL: self.baseURL, drive: self.drive, json: entry) {
+                            foundItem(file)
+                        }
+                    }
+                    let next: URL? = (json["@odata.nextLink"] as? String).flatMap { URL(string: $0) }
+                    if !progress.isCancelled, let next = next {
+                        self.search(startPath, query: query, next: next, progress: progress, foundItem: foundItem, completionHandler: completionHandler)
+                    } else {
+                        completionHandler(responseError ?? error)
+                    }
+                    return
+                }
+            }
+            completionHandler(responseError ?? error)
+        })
+        progress.cancellationHandler = { [weak task] in
+            task?.cancel()
+        }
+        progress.setUserInfoObject(Date(), forKey: .startingTimeKey)
+        task.resume()
+    }
+}
+// codebeat:enable[ARITY]
+
+internal extension OneDriveFileProvider {
+    static let dateFormatter = DateFormatter()
+    static let decimalFormatter = NumberFormatter()
+    
+    func mapMediaInfo(_ json: [String: Any]) -> (dictionary: [String: Any], keys: [String]) {
+        
+        func spaceCamelCase(_ text: String) -> String {
+            var newString: String = ""
+            
+            let upperCase = CharacterSet.uppercaseLetters
+            for scalar in text.unicodeScalars {
+                if upperCase.contains(scalar) {
+                    newString.append(" ")
+                }
+                let character = Character(scalar)
+                newString.append(character)
+            }
+            
+            return newString.capitalized
+        }
+        
+        var dic = [String: Any]()
+        var keys = [String]()
+        
+        func add(key: String, value: Any?) {
+            if let value = value {
+                keys.append(key)
+                dic[key] = value
+            }
+        }
+        
+        if let parent = json["image"] as? [String: Any] ?? json["video"] as? [String: Any], let height = parent["height"] as? UInt64, let width = parent["width"] as? UInt64 {
+            add(key: "Dimensions", value: "\(width)x\(height)")
+        }
+        if let location = json["location"] as? [String: Any], let latitude = location["latitude"] as? Double, let longitude = location["longitude"] as? Double {
+            OneDriveFileProvider.decimalFormatter.numberStyle = .decimal
+            OneDriveFileProvider.decimalFormatter.maximumFractionDigits = 5
+            let latStr = OneDriveFileProvider.decimalFormatter.string(from: NSNumber(value: latitude))!
+            let longStr = OneDriveFileProvider.decimalFormatter.string(from: NSNumber(value: longitude))!
+            add(key: "Location", value: "\(latStr), \(longStr)")
+        }
+        if let parent = json["image"] as? [String: Any] ?? json["video"] as? [String: Any], let duration = parent["duration"] as? UInt64 {
+            add(key: "Duration", value: (TimeInterval(duration) / 1000).formatshort)
+        }
+        if let timeTakenStr = json["takenDateTime"] as? String, let timeTaken = Date(rfcString: timeTakenStr) {
+            OneDriveFileProvider.dateFormatter.dateFormat = "yyyy-MM-dd HH:mm:ss"
+            add(key: "Date taken", value:  OneDriveFileProvider.dateFormatter.string(from: timeTaken))
+        }
+        
+        if let photo = json["photo"] as? [String: Any] {
+            add(key: "Device make", value: photo["cameraMake"] as? String)
+            add(key: "Device model", value: photo["cameraModel"] as? String)
+            add(key: "focalLength", value: photo["focalLength"] as? Double)
+            add(key: "fNumber", value: photo["fNumber"] as? Double)
+            if let expNom = photo["exposureNumerator"] as? Double, let expDen = photo["exposureDenominator"] as? Double {
+                add(key: "Exposure time", value: "\(Int(expNom))/\(Int(expDen))")
+            }
+            add(key: "ISO speed", value: photo["iso"] as? Int64)
+        }
+        
+        if let audio = json["audio"] as? [String: Any] {
+            for (key, value) in audio {
+                if key == "bitrate" || key == "isVariableBitrate" { continue }
+                let casedKey = spaceCamelCase(key)
+                add(key: casedKey, value: value)
+            }
+        }
+        
+        add(key: "Bitrate", value: (json["video"] as? NSDictionary)?["bitrate"] as? Int)
+        
+        return (dic, keys)
+    }
+}
@@ -8,207 +8,363 @@

 import Foundation

-open class RemoteOperationHandle: OperationHandle {
-    
-    internal var tasks: [Weak<URLSessionTask>]
-    
-    private var _inProgress = false
-    open var inProgress: Bool {
-        return _inProgress
+/// A protocol defines properties for errors returned by HTTP/S based providers.
+/// Including Dropbox, OneDrive and WebDAV.
+public protocol FileProviderHTTPError: Error, CustomStringConvertible {
+    /// HTTP status codes as an enum.
+    typealias Code = FileProviderHTTPErrorCode
+    /// HTTP status code returned for error by server.
+    var code: FileProviderHTTPErrorCode { get }
+    /// Path of file/folder casued that error
+    var path: String { get }
+    /// Contents returned by server as error description
+    var errorDescription: String? { get }
+}
+
+extension FileProviderHTTPError {
+    public var description: String {
+        return code.description
    }
    
-    init(tasks: [URLSessionTask]) {
-        self.tasks = tasks.map { Weak<URLSessionTask>($0) }
-        _inProgress = true
-    }
-    
-    internal func add(task: URLSessionTask) {
-        tasks.append(Weak<URLSessionTask>(task))
-    }
-    
-    private func reape() {
-        self.tasks = tasks.filter { $0.value != nil }
-    }
-    
-    open var progress: Float {
-        let bytesSoFar = self.bytesSoFar
-        let totalBytes = self.totalBytes
-        return totalBytes > 0 ? Float(Double(bytesSoFar) / Double(totalBytes)) : Float.nan
-    }
-    
-    open var bytesSoFar: Int64 {
-        return tasks.reduce(0) {
-            if let task = $1.value as? URLSessionUploadTask {
-                return $0 + task.countOfBytesSent
-            } else {
-                return $0 + ($1.value?.countOfBytesReceived ?? 0)
-            }
-        }
-    }
-    
-    open var totalBytes: Int64 {
-        return tasks.reduce(0) {
-            if let task = $1.value as? URLSessionUploadTask {
-                return $0 + task.countOfBytesExpectedToSend
-            } else {
-                return $0 + ($1.value?.countOfBytesExpectedToSend ?? 0)
-            }
-        }
-    }
-    
-    open func cancel() {
-        for taskbox in tasks {
-            taskbox.value?.cancel()
-        }
-        _inProgress = false
+    public var localizedDescription: String {
+        return description
    }
 }

-class SessionDelegate: NSObject, URLSessionDataDelegate, URLSessionDownloadDelegate {
+/// Defines HTTP Authentication method required to access
+public enum HTTPAuthenticationType {
+    /// Basic method for authentication
+    case basic
+    /// Digest method for authentication
+    case digest
+    /// OAuth 1.0 method for authentication (OAuth)
+    case oAuth1
+    /// OAuth 2.0 method for authentication (Bearer)
+    case oAuth2
+}
+
+internal var completionHandlersForTasks = [String: [Int: SimpleCompletionHandler]]()
+internal var downloadCompletionHandlersForTasks = [String: [Int: (URL) -> Void]]()
+internal var dataCompletionHandlersForTasks = [String: [Int: (Data) -> Void]]()
+
+internal func initEmptySessionHandler(_ uuid: String) {
+    completionHandlersForTasks[uuid] = [:]
+    downloadCompletionHandlersForTasks[uuid] = [:]
+    dataCompletionHandlersForTasks[uuid] = [:]
+}
+
+internal func removeSessionHandler(for uuid: String) {
+    _ = completionHandlersForTasks.removeValue(forKey: uuid)
+    _ = downloadCompletionHandlersForTasks.removeValue(forKey: uuid)
+    _ = dataCompletionHandlersForTasks.removeValue(forKey: uuid)
+}
+
+/// All objects set to `FileProviderRemote.session` must be an instance of this class
+final public class SessionDelegate: NSObject, URLSessionDataDelegate, URLSessionDownloadDelegate, URLSessionStreamDelegate {
    
-    weak var fileProvider: FileProvider?
+    weak var fileProvider: (FileProviderBasicRemote & FileProviderOperations)?
    var credential: URLCredential?
    
-    var finishDownloadHandler: ((_ session: Foundation.URLSession, _ downloadTask: URLSessionDownloadTask, _ didFinishDownloadingToURL: URL) -> Void)?
-    var didSendDataHandler: ((_ session: Foundation.URLSession, _ task: URLSessionTask, _ bytesSent: Int64, _ totalBytesSent: Int64, _ totalBytesExpectedToSend: Int64) -> Void)?
-    var didReceivedData: ((_ session: Foundation.URLSession, _ downloadTask: URLSessionDownloadTask, _ bytesWritten: Int64, _ totalBytesWritten: Int64, _ totalBytesExpectedToWrite: Int64) -> Void)?
+    /// Forwardng URLSessionDownloadTaskDelegate call
+    public var finishDownloadHandler: ((_ session: URLSession, _ downloadTask: URLSessionDownloadTask, _ didFinishDownloadingToURL: URL) -> Void)?
+    /// Forwardng URLSessionTaskDelegate call
+    public var didSendDataHandler: ((_ session: URLSession, _ task: URLSessionTask, _ bytesSent: Int64, _ totalBytesSent: Int64, _ totalBytesExpectedToSend: Int64) -> Void)?
+    /// Forwardng URLSessionDownloadTaskDelegate call
+    public var didReceivedData: ((_ session: URLSession, _ downloadTask: URLSessionDownloadTask, _ bytesWritten: Int64, _ totalBytesWritten: Int64, _ totalBytesExpectedToWrite: Int64) -> Void)?
+    /// Forwardng URLSessionStreamTaskDelegate call
+    public var didBecomeStream :((_ session: URLSession, _ taskId: Int, _ didBecome: InputStream, _ outputStream: OutputStream) -> Void)?
    
-    init(fileProvider: FileProvider, credential: URLCredential?) {
+    public init(fileProvider: FileProviderBasicRemote & FileProviderOperations) {
        self.fileProvider = fileProvider
-        self.credential = credential
+        self.credential = fileProvider.credential
+    }
+    
+    open override func observeValue(forKeyPath keyPath: String?, of object: Any?, change: [NSKeyValueChangeKey : Any]?, context: UnsafeMutableRawPointer?) {
+        if let progress = context?.load(as: Progress.self), let newVal = change?[.newKey] as? Int64 {
+            switch keyPath ?? "" {
+            case #keyPath(URLSessionTask.countOfBytesReceived):
+                progress.completedUnitCount = newVal
+                if let startTime = progress.userInfo[ProgressUserInfoKey.startingTimeKey] as? Date, let task = object as? URLSessionTask {
+                    let elapsed = Date().timeIntervalSince(startTime)
+                    let throughput = Double(newVal) / elapsed
+                    progress.setUserInfoObject(NSNumber(value: throughput), forKey: .throughputKey)
+                    if task.countOfBytesExpectedToReceive > 0 {
+                        let remain = task.countOfBytesExpectedToReceive - task.countOfBytesReceived
+                        let estimatedTimeRemaining = Double(remain) / elapsed
+                        progress.setUserInfoObject(NSNumber(value: estimatedTimeRemaining), forKey: .estimatedTimeRemainingKey)
+                    }
+                }
+            case #keyPath(URLSessionTask.countOfBytesSent):
+                progress.completedUnitCount = newVal
+                if let startTime = progress.userInfo[ProgressUserInfoKey.startingTimeKey] as? Date, let task = object as? URLSessionTask {
+                    let elapsed = Date().timeIntervalSince(startTime)
+                    let throughput = Double(newVal) / elapsed
+                    progress.setUserInfoObject(NSNumber(value: throughput), forKey: .throughputKey)
+                    if task.countOfBytesExpectedToSend > 0 {
+                        let remain = task.countOfBytesExpectedToSend - task.countOfBytesSent
+                        let estimatedTimeRemaining = Double(remain) / elapsed
+                        progress.setUserInfoObject(NSNumber(value: estimatedTimeRemaining), forKey: .estimatedTimeRemainingKey)
+                    }
+                }
+            case #keyPath(URLSessionTask.countOfBytesExpectedToReceive), #keyPath(URLSessionTask.countOfBytesExpectedToSend):
+                progress.totalUnitCount = newVal
+            default:
+                super.observeValue(forKeyPath: keyPath, of: object, change: change, context: context)
+            }
+        }
    }
    
    // codebeat:disable[ARITY]
-    func urlSession(_ session: URLSession, downloadTask: URLSessionDownloadTask, didFinishDownloadingTo location: URL) {
-        self.finishDownloadHandler?(session, downloadTask, location)
-        return
+    public func urlSession(_ session: URLSession, task: URLSessionTask, didCompleteWithError error: Error?) {
+        if task is URLSessionDownloadTask {
+            task.removeObserver(self, forKeyPath: #keyPath(URLSessionTask.countOfBytesReceived))
+            task.removeObserver(self, forKeyPath: #keyPath(URLSessionTask.countOfBytesExpectedToReceive))
+        }
+        if task is URLSessionUploadTask {
+            task.removeObserver(self, forKeyPath: #keyPath(URLSessionTask.countOfBytesSent))
+            //task.removeObserver(self, forKeyPath: #keyPath(URLSessionTask.countOfBytesExpectedToSend))
+        }
+        if !(error == nil && task is URLSessionDownloadTask) {
+            let completionHandler = completionHandlersForTasks[session.sessionDescription!]?[task.taskIdentifier] ?? nil
+            completionHandler?(error)
+            _ = completionHandlersForTasks[session.sessionDescription!]?.removeValue(forKey: task.taskIdentifier)
+        }
+        
+        guard let json = task.taskDescription?.deserializeJSON(),
+            let op = FileOperationType(json: json), let fileProvider = fileProvider else {
+                return
+        }
+        
+        if !(task is URLSessionDownloadTask), case FileOperationType.fetch = op {
+            return
+        }
+        if #available(iOS 9.0, macOS 10.11, *) {
+            if task is URLSessionStreamTask {
+                return
+            }
+        }
+        
+        DispatchQueue.main.async {
+            if error != nil {
+                fileProvider.delegate?.fileproviderFailed(fileProvider, operation: op)
+            } else {
+                fileProvider.delegate?.fileproviderSucceed(fileProvider, operation: op)
+            }
+        }
    }
    
-    func urlSession(_ session: URLSession, task: URLSessionTask, didSendBodyData bytesSent: Int64, totalBytesSent: Int64, totalBytesExpectedToSend: Int64) {
+    public func urlSession(_ session: URLSession, dataTask: URLSessionDataTask, didReceive data: Data) {
+        let completionHandler = dataCompletionHandlersForTasks[session.sessionDescription!]?[dataTask.taskIdentifier] ?? nil
+        completionHandler?(data)
+        _ = dataCompletionHandlersForTasks[session.sessionDescription!]?.removeValue(forKey: dataTask.taskIdentifier)
+    }
+    
+    public func urlSession(_ session: URLSession, downloadTask: URLSessionDownloadTask, didFinishDownloadingTo location: URL) {
+        self.finishDownloadHandler?(session, downloadTask, location)
+        
+        let dcompletionHandler = downloadCompletionHandlersForTasks[session.sessionDescription!]?[downloadTask.taskIdentifier]
+        dcompletionHandler?(location)
+        _ = downloadCompletionHandlersForTasks[session.sessionDescription!]?.removeValue(forKey: downloadTask.taskIdentifier)
+        _ = completionHandlersForTasks[session.sessionDescription!]?.removeValue(forKey: downloadTask.taskIdentifier)
+    }
+    
+    public func urlSession(_ session: URLSession, task: URLSessionTask, didSendBodyData bytesSent: Int64, totalBytesSent: Int64, totalBytesExpectedToSend: Int64) {
        self.didSendDataHandler?(session, task, bytesSent, totalBytesSent, totalBytesExpectedToSend)
        
-        guard let desc = task.taskDescription, let json = jsonToDictionary(desc) else {
+        guard let json = task.taskDescription?.deserializeJSON(),
+              let op = FileOperationType(json: json), let fileProvider = fileProvider else {
            return
        }
-        guard let type = json["type"] as? String, let source = json["source"] as? String else {
-            return
-        }
-        let dest = json["dest"] as? String
-        let op : FileOperationType
-        switch type {
-        case "Create":
-            op = .create(path: source)
-        case "Copy":
-            guard let dest = dest else { return }
-            op = .copy(source: source, destination: dest)
-        case "Move":
-            guard let dest = dest else { return }
-            op = .move(source: source, destination: dest)
-        case "Modify":
-            op = .modify(path: source)
-        case "Remove":
-            op = .remove(path: source)
-        case "Link":
-            guard let dest = dest else { return }
-            op = .link(link: source, target: dest)
+        
+        switch op {
+        case .create(path: let path):
+            if path.hasSuffix("/") { return }
+            break
+        case .modify:
+            break
+        case .copy(source: let source, destination: _) where source.hasPrefix("file://"):
+            break
        default:
            return
        }
        
        let progress = Float(totalBytesSent) / Float(totalBytesExpectedToSend)
        
-        fileProvider?.delegate?.fileproviderProgress(fileProvider!, operation: op, progress: progress)
+        DispatchQueue.main.async {
+            fileProvider.delegate?.fileproviderProgress(fileProvider, operation: op, progress: progress)
+        }
    }
    
-    func urlSession(_ session: URLSession, downloadTask: URLSessionDownloadTask, didWriteData bytesWritten: Int64, totalBytesWritten: Int64, totalBytesExpectedToWrite: Int64) {
+    public func urlSession(_ session: URLSession, downloadTask: URLSessionDownloadTask, didWriteData bytesWritten: Int64, totalBytesWritten: Int64, totalBytesExpectedToWrite: Int64) {
        self.didReceivedData?(session, downloadTask, bytesWritten, totalBytesWritten, totalBytesExpectedToWrite)
        
-        guard let desc = downloadTask.taskDescription, let json = jsonToDictionary(desc), let source = json["source"] as? String, let dest = json["dest"] as? String else {
+        if totalBytesExpectedToWrite == NSURLSessionTransferSizeUnknown { return }
+        
+        guard let json = downloadTask.taskDescription?.deserializeJSON(),
+              let op = FileOperationType(json: json), let fileProvider = fileProvider else {
            return
        }
        
-        fileProvider?.delegate?.fileproviderProgress(fileProvider!, operation: .copy(source: source, destination: dest), progress: Float(totalBytesWritten) / Float(totalBytesExpectedToWrite))
+        DispatchQueue.main.async {
+            fileProvider.delegate?.fileproviderProgress(fileProvider, operation: op, progress: Float(totalBytesWritten) / Float(totalBytesExpectedToWrite))
+        }
    }
    
-    func urlSession(_ session: URLSession, task: URLSessionTask, didReceive challenge: URLAuthenticationChallenge, completionHandler: @escaping (URLSession.AuthChallengeDisposition, URLCredential?) -> Void) {
-        let deposition: Foundation.URLSession.AuthChallengeDisposition = credential != nil ? .useCredential : .performDefaultHandling
-        completionHandler(deposition, credential)
+    public func urlSession(_ session: URLSession, task: URLSessionTask, didReceive challenge: URLAuthenticationChallenge, completionHandler: @escaping (URLSession.AuthChallengeDisposition, URLCredential?) -> Void) {
+        authenticate(didReceive: challenge, completionHandler: completionHandler)
    }
    
-    func urlSession(_ session: URLSession, didReceive challenge: URLAuthenticationChallenge, completionHandler: @escaping (URLSession.AuthChallengeDisposition, URLCredential?) -> Void) {
-        let deposition: Foundation.URLSession.AuthChallengeDisposition = credential != nil ? .useCredential : .performDefaultHandling
-        completionHandler(deposition, credential)
+    public func urlSession(_ session: URLSession, didReceive challenge: URLAuthenticationChallenge, completionHandler: @escaping (URLSession.AuthChallengeDisposition, URLCredential?) -> Void) {
+        authenticate(didReceive: challenge, completionHandler: completionHandler)
+    }
+    
+    func authenticate(didReceive challenge: URLAuthenticationChallenge, completionHandler: @escaping (URLSession.AuthChallengeDisposition, URLCredential?) -> Void) {
+        switch (challenge.previousFailureCount, credential != nil) {
+        case (0...1, true):
+            completionHandler(.useCredential, credential)
+        case (0, false):
+            completionHandler(.useCredential, challenge.proposedCredential)
+        default:
+            completionHandler(.performDefaultHandling, nil)
+        }
+    }
+    
+    @available(iOS 9.0, macOS 10.11, *)
+    public func urlSession(_ session: URLSession, streamTask: URLSessionStreamTask, didBecome inputStream: InputStream, outputStream: OutputStream) {
+        self.didBecomeStream?(session, streamTask.taskIdentifier, inputStream, outputStream)
    }
 }

-public enum FileProviderHTTPErrorCode: Int {
+/// HTTP status codes as an enum.
+public enum FileProviderHTTPErrorCode: Int, CustomStringConvertible {
+    /// `Continue` informational status with HTTP code 100
    case `continue` = 100
+    /// `Switching Protocols` informational status with HTTP code 101
    case switchingProtocols = 101
+    /// `Processing` informational status with HTTP code 102
    case processing = 102
+    /// `OK` success status with HTTP code 200
    case ok = 200
+    /// `Created` success status with HTTP code 201
    case created = 201
+    /// `Accepted` success status with HTTP code 202
    case accepted = 202
+    /// `Non Authoritative Information` success status with HTTP code 203
    case nonAuthoritativeInformation = 203
+    /// `No Content` success status with HTTP code 204
    case noContent = 204
+    /// `ResetcContent` success status with HTTP code 205
    case resetContent = 205
+    /// `Partial Content` success status with HTTP code 206
    case partialContent = 206
+    /// `Multi Status` success status with HTTP code 207
    case multiStatus = 207
+    /// `Already Reported` success status with HTTP code 208
    case alreadyReported = 208
+    /// `IM Used` success status with HTTP code 226
    case imUsed = 226
+    /// `Multiple Choices` redirection status with HTTP code 300
    case multipleChoices = 300
+    /// `Moved Permanently` redirection status with HTTP code 301
    case movedPermanently = 301
+    /// `Found` redirection status with HTTP code 302
    case found = 302
+    /// `See Other` redirection status with HTTP code 303
    case seeOther = 303
+    /// `Not Modified` redirection status with HTTP code 304
    case notModified = 304
+    /// `Use Proxy` redirection status with HTTP code 305
    case useProxy = 305
+    /// `Switch Proxy` redirection status with HTTP code 306
    case switchProxy = 306
+    /// `Temporary Redirect` redirection status with HTTP code 307
    case temporaryRedirect = 307
+    /// `Permanent Redirect` redirection status with HTTP code 308
    case permanentRedirect = 308
+    /// `Bad Request` client error status with HTTP code 400
    case badRequest = 400
+    /// `Unauthorized` client error status with HTTP code 401
    case unauthorized = 401
+    /// `Payment Required` client error status with HTTP code 402
    case paymentRequired = 402
+    /// `Forbidden` client error status with HTTP code 403
    case forbidden = 403
+    /// `Not Found` client error status with HTTP code 404
    case notFound = 404
+    /// `Method Not Allowed` client error status with HTTP code 405
    case methodNotAllowed = 405
+    /// `Not Acceptable` client error status with HTTP code 406
    case notAcceptable = 406
+    /// `Proxy Authentication Required` client error status with HTTP code 407
    case proxyAuthenticationRequired = 407
+    /// `Request Timeout` client error status with HTTP code 408
    case requestTimeout = 408
+    /// `Conflict` client error status with HTTP code 409
    case conflict = 409
+    /// `Gone` client error status with HTTP code 410
    case gone = 410
+    /// `Length Required` client error status with HTTP code 411
    case lengthRequired = 411
+    /// `Precondition Failed` client error status with HTTP code 412
    case preconditionFailed = 412
+    /// `Payload Too Large` client error status with HTTP code 413
    case payloadTooLarge = 413
+    /// `URI Too Long` client error status with HTTP code 414
    case uriTooLong = 414
+    /// `Unsupported Media Type` status with HTTP code 415
    case unsupportedMediaType = 415
+    /// `Range Not Satisfiable` client error status with HTTP code 416
    case rangeNotSatisfiable = 416
+    /// `Expectation Failed` client error status with HTTP code 417
    case expectationFailed = 417
+    /// `Misdirected Request` client error status with HTTP code 421
    case misdirectedRequest = 421
+    /// `Unprocessable Entity` client error status with HTTP code 422
    case unprocessableEntity = 422
+    /// `Locked` client error status with HTTP code 423
    case locked = 423
+    /// `Failed Dependency` client error status with HTTP code 424
    case failedDependency = 424
+    /// `Unordered Collection` client error status with HTTP code 425
    case unorderedCollection = 425
+    /// `Upgrade Required` client error status with HTTP code 426
    case upgradeRequired = 426
+    /// `Precondition Required` client error status with HTTP code 428
    case preconditionRequired = 428
+    /// `Too Many Requests` client error status with HTTP code 429
    case tooManyRequests = 429
+    /// `Request Header Fields Too Large` client error status with HTTP code 431
    case requestHeaderFieldsTooLarge = 431
+    /// `Unavailable For Legal Reasons` client error status with HTTP code 451
    case unavailableForLegalReasons = 451
+    /// `Internal Server Error` server error status with HTTP code 500
    case internalServerError = 500
+    /// `Bad Gateway` server error status with HTTP code 502
    case badGateway = 502
+    /// `Service Unavailable` server error status with HTTP code 503
    case serviceUnavailable = 503
+    /// `Gateway Timeout` server error status with HTTP code 504
    case gatewayTimeout = 504
+    /// `HTTP Version Not Supported` server error status with HTTP code 505
    case httpVersionNotSupported = 505
-    case variantlsoNegotiates = 506
+    /// `Variant Also Negotiates` server error status with HTTP code 506
+    case variantAlsoNegotiates = 506
+    /// `Insufficient Storage` server error status with HTTP code 507
    case insufficientStorage = 507
+    /// `Loop Detected` server error status with HTTP code 508
    case loopDetected = 508
+    /// `Bandwidth Limit Exceeded` server error status with HTTP code 509
    case bandwidthLimitExceeded = 509
+    /// `Not Extended` server error status with HTTP code 510
    case notExtended = 510
+    /// `Network Authentication Required` server error status with HTTP code 511
    case networkAuthenticationRequired = 511
    
-    fileprivate static let status1xx = [100: "Continue", 101: "Switching Protocols", 102: "Processing"]
-    fileprivate static let status2xx = [200: "OK", 201: "Created", 202: "Accepted", 203: "Non-Authoritative Information", 204: "No Content", 205: "Reset Content", 206: "Partial Content", 207: "Multi-Status", 208: "Already Reported", 226: "IM Used"]
-    fileprivate static let status3xx = [300: "Multiple Choices", 301: "Moved Permanently", 302: "Found", 303: "See Other", 304: "Not Modified", 305: "Use Proxy", 306: "Switch Proxy", 307: "Temporary Redirect", 308: "Permanent Redirect"]
-    fileprivate static let status4xx = [400: "Bad Request", 401: "Unauthorized/Expired Session", 402: "Payment Required", 403: "Forbidden", 404: "Not Found", 405: "Method Not Allowed", 406: "Not Acceptable", 407: "Proxy Authentication Required", 408: "Request Timeout", 409: "Conflict", 410: "Gone", 411: "Length Required", 412: "Precondition Failed", 413: "Payload Too Large", 414: "URI Too Long", 415: "Unsupported Media Type", 416: "Range Not Satisfiable", 417: "Expectation Failed", 421: "Misdirected Request", 422: "Unprocessable Entity", 423: "Locked", 424: "Failed Dependency", 425: "Unordered Collection", 426: "Upgrade Required", 428: "Precondition Required", 429: "Too Many Requests", 431: "Request Header Fields Too Large", 451: "Unavailable For Legal Reasons"]
-    fileprivate static let status5xx = [500: "Internal Server Error", 501: "Not Implemented", 502: "Bad Gateway", 503: "Service Unavailable", 504: "Gateway Timeout", 505: "HTTP Version Not Supported", 506: "Variant Also Negotiates", 507: "Insufficient Storage", 508: "Loop Detected", 509: "Bandwidth Limit Exceeded", 510: "Not Extended", 511: "Network Authentication Required"]
+    fileprivate static let status1xx: [Int: String] = [100: "Continue", 101: "Switching Protocols", 102: "Processing"]
+    fileprivate static let status2xx: [Int: String] = [200: "OK", 201: "Created", 202: "Accepted", 203: "Non-Authoritative Information", 204: "No Content", 205: "Reset Content", 206: "Partial Content", 207: "Multi-Status", 208: "Already Reported", 226: "IM Used"]
+    fileprivate static let status3xx: [Int: String] = [300: "Multiple Choices", 301: "Moved Permanently", 302: "Found", 303: "See Other", 304: "Not Modified", 305: "Use Proxy", 306: "Switch Proxy", 307: "Temporary Redirect", 308: "Permanent Redirect"]
+    fileprivate static let status4xx: [Int: String] = [400: "Bad Request", 401: "Unauthorized/Expired Session", 402: "Payment Required", 403: "Forbidden", 404: "Not Found", 405: "Method Not Allowed", 406: "Not Acceptable", 407: "Proxy Authentication Required", 408: "Request Timeout", 409: "Conflict", 410: "Gone", 411: "Length Required", 412: "Precondition Failed", 413: "Payload Too Large", 414: "URI Too Long", 415: "Unsupported Media Type", 416: "Range Not Satisfiable", 417: "Expectation Failed", 421: "Misdirected Request", 422: "Unprocessable Entity", 423: "Locked", 424: "Failed Dependency", 425: "Unordered Collection", 426: "Upgrade Required", 428: "Precondition Required", 429: "Too Many Requests", 431: "Request Header Fields Too Large", 451: "Unavailable For Legal Reasons"]
+    fileprivate static let status5xx: [Int: String] = [500: "Internal Server Error", 501: "Not Implemented", 502: "Bad Gateway", 503: "Service Unavailable", 504: "Gateway Timeout", 505: "HTTP Version Not Supported", 506: "Variant Also Negotiates", 507: "Insufficient Storage", 508: "Loop Detected", 509: "Bandwidth Limit Exceeded", 510: "Not Extended", 511: "Network Authentication Required"]
    
    public var description: String {
        switch self.rawValue {
@@ -222,6 +378,7 @@ public enum FileProviderHTTPErrorCode: Int {
        }
    }
    
+    /// Description of status based on first digit which indicated fail or success.
    public var typeDescription: String {
        switch self.rawValue {
        case 100...199: return "Informational"
@@ -229,7 +386,7 @@ public enum FileProviderHTTPErrorCode: Int {
        case 300...399: return "Redirection"
        case 400...499: return "Client Error"
        case 500...599: return "Server Error"
-        default: return "Server Error"
+        default: return "Unknown Error"
        }
    }
 }
@@ -11,22 +11,34 @@ import Foundation
 // This client implementation is for little-endian platform, namely x86, x64 & arm
 // For big-endian platforms like PowerPC, there must be a huge overhaul

-protocol SMBProtocolClientDelegate: class {
-    func receivedSMB2Response(_ header: SMB2.Header, response: SMBResponse)
+protocol FileProviderSMBTaskDelegate: class {
+    func receivedResponse(client: FileProviderSMBTask, response: SMBResponse, for: SMBRequest)
 }

-class SMB2ProtocolClient: FPSStreamTask {
-    var currentMessageID: UInt64 = 0
-    var sessionId: UInt64 = 0
+class FileProviderSMBTask: FileProviderStreamTask {
+    var timeout: TimeInterval = 30
    
-    weak var delegate: SMBProtocolClientDelegate?
+    private(set) var lastMessageID: UInt64 = 0
+    private(set) var sessionId: UInt64 = 0
+    private func messageId() -> UInt64 {
+        defer {
+            lastMessageID += 1
+        }
+        return lastMessageID
+    }
+    
+    private(set) var establishedTrees = Array<SMB2.TreeConnectResponse>()
+    private(set) var requestStack = [Int: SMBRequest]()
+    private(set) var responseStack = [Int: SMBResponse]()
+    
+    weak var delegate: FileProviderSMBTaskDelegate?
    
    func sendNegotiate(completionHandler: SimpleCompletionHandler) -> UInt64 {
        let mId = messageId()
        let smbHeader = SMB2.Header(command: .NEGOTIATE, creditRequestResponse: UInt16(126), messageId: mId, treeId: UInt32(0), sessionId: UInt64(0))
        let msg = SMB2.NegotiateRequest()
        let data = createSMB2Message(header: smbHeader, message: msg)
-        self.writeData(data, timeout: 0, completionHandler: { (e) in
+        self.write(data, timeout: timeout, completionHandler: { (e) in
            completionHandler?(e)
        })
        return mId
@@ -38,9 +50,9 @@ class SMB2ProtocolClient: FPSStreamTask {
        let smbHeader = SMB2.Header(command: SMB2.Command.SESSION_SETUP, creditRequestResponse: credit, messageId: mId, treeId: UInt32(0), sessionId: sessionId)
        let msg = SMB2.SessionSetupRequest(singing: [])
        let data = createSMB2Message(header: smbHeader, message: msg)
-        self.writeData(data, timeout: 0, completionHandler: { (e) in
+        self.write(data, timeout: timeout, completionHandler: { (e) in
            if self.sessionId == 0 {
-                self.readData(OfMinLength: 64, maxLength: 65536, timeout: 30, completionHandler: { (data, eof, e2) in
+                self.readData(ofMinLength: 64, maxLength: 65536, timeout: self.timeout, completionHandler: { (data, eof, e2) in
                    // TODO: set session id
                    completionHandler?(e2 ?? e)
                })
@@ -56,26 +68,24 @@ class SMB2ProtocolClient: FPSStreamTask {
        }
        let mId = messageId()
        let smbHeader = SMB2.Header(command: .TREE_CONNECT, creditRequestResponse: 123, messageId: mId, treeId: 0, sessionId: sessionId)
-        var share = ""
        let cmp = url.pathComponents
-        if cmp.count > 0 {
-            share = cmp[0]
-        }
+        let share = cmp.first ?? ""
        let tcHeader = SMB2.TreeConnectRequest.Header(flags: [])
        let msg = SMB2.TreeConnectRequest(header: tcHeader, host: host, share: share)
        let data = createSMB2Message(header: smbHeader, message: msg!)
-        self.writeData(data, timeout: 0, completionHandler: { (e) in
+        self.write(data, timeout: timeout, completionHandler: { (e) in
            completionHandler?(e)
            
        })
        return mId
    }
+    
    func sendTreeDisconnect(id treeId: UInt32, completionHandler: SimpleCompletionHandler) -> UInt64 {
        let mId = messageId()
        let smbHeader = SMB2.Header(command: .TREE_DISCONNECT, creditRequestResponse: 111, messageId: mId, treeId: treeId, sessionId: sessionId)
        let msg = SMB2.TreeDisconnect()
        let data = createSMB2Message(header: smbHeader, message: msg)
-        self.writeData(data, timeout: 0, completionHandler: { (e) in
+        self.write(data, timeout: timeout, completionHandler: { (e) in
            completionHandler?(e)
        })
        return mId
@@ -86,21 +96,19 @@ class SMB2ProtocolClient: FPSStreamTask {
        let smbHeader = SMB2.Header(command: .LOGOFF, creditRequestResponse: 0, messageId: mId, treeId: 0, sessionId: sessionId)
        let msg = SMB2.LogOff()
        let data = createSMB2Message(header: smbHeader, message: msg)
-        self.writeData(data, timeout: 0, completionHandler: { (e) in
+        self.write(data, timeout: timeout, completionHandler: { (e) in
            completionHandler?(e)
        })
        return mId
    }
    
-    func messageId() -> UInt64 {
-        defer {
-            currentMessageID += 1
-        }
-        return currentMessageID
+    func reset() {
+        
    }
-    
-    // MARK: create and analyse messages
-    
+}
+
+// MARK: create and analyse messages
+extension FileProviderSMBTask {
    func determineSMBVersion(_ data: Data) -> Float {
        let smbverChar: Int8 = Int8(bitPattern: data.first ?? 0)
        let version = 0 - smbverChar
@@ -116,7 +124,7 @@ class SMB2ProtocolClient: FPSStreamTask {
            throw SMBFileProviderError.incompatibleHeader
        }
        let headersize = MemoryLayout<SMB1.Header>.size
-        let header: SMB1.Header = decode(data)
+        let header: SMB1.Header = data.scanValue()!
        var blocks = [(params: [UInt16], message: Data?)]()
        var offset = headersize
        while offset < data.count {
@@ -128,7 +136,7 @@ class SMB2ProtocolClient: FPSStreamTask {
            offset += MemoryLayout<UInt8>.size
            var rawParamWords = [UInt8](buffer[offset..<(offset + paramWordsCount * 2)])
            let paramData = Data(bytesNoCopy: UnsafeMutablePointer<UInt8>(&rawParamWords), count: rawParamWords.count, deallocator: .free)
-            paramWords = decode(paramData)
+            paramWords = paramData.scanValue()!
            offset += paramWordsCount * 2
            let messageBytesCount = Int(UInt16(buffer[0]) + UInt16(buffer[1]) << 8)
            offset += MemoryLayout<UInt16>.size
@@ -143,7 +151,7 @@ class SMB2ProtocolClient: FPSStreamTask {
        return (header, blocks)
    }
    
-    func digestSMB2Message(_ data: Data) throws -> (header: SMB2.Header, message: SMBResponse?)? {
+    func digestSMB2Message(_ data: Data) throws -> SMBResponse? {
        guard data.count > 65 else {
            throw URLError(.badServerResponse)
        }
@@ -154,7 +162,7 @@ class SMB2ProtocolClient: FPSStreamTask {
        let headerData = data.subdata(in: 0..<headersize)
        let messageSize = data.count - headersize
        let messageData = data.subdata(in: headersize..<(headersize + messageSize))
-        let header: SMB2.Header = decode(headerData)
+        let header: SMB2.Header = headerData.scanValue()!
        switch header.command {
        case .NEGOTIATE:
            return (header, SMB2.NegotiateResponse(data: messageData))
@@ -200,8 +208,7 @@ class SMB2ProtocolClient: FPSStreamTask {
    }
    
    func createSMBMessage(header: SMB1.Header, blocks: [(params: Data?, message: Data?)]) -> Data {
-        var headerv = header
-        var result = encode(&headerv)
+        var result = Data(value: header)
        for block in blocks {
            var paramWordsCount = UInt8(block.params?.count ?? 0)
            result.append(&paramWordsCount, count: MemoryLayout.size(ofValue: paramWordsCount))
@@ -218,9 +225,8 @@ class SMB2ProtocolClient: FPSStreamTask {
        return result
    }
    
-    func createSMB2Message(header: SMB2.Header, message: SMBRequest) -> Data {
-        var headerv = header
-        var result = encode(&headerv)
+    func createSMB2Message(header: SMB2.Header, message: SMBRequestBody) -> Data {
+        var result = Data(value: header)
        result.append(message.data())
        return result
    }
@@ -8,27 +8,54 @@

 import Foundation

-open class SMBFileProvider: FileProvider, FileProviderMonitor {
-    open static var type: String = "Samba"
-    open var isPathRelative: Bool = true
+class SMBFileProvider: FileProvider, FileProviderMonitor {
+    open class var type: String { return "SMB" }
    open var baseURL: URL?
    open var currentPath: String = ""
    open var dispatch_queue: DispatchQueue
+    open var operation_queue: OperationQueue
    open weak var delegate: FileProviderDelegate?
-    open let credential: URLCredential?
+    open var credential: URLCredential?
    
    public typealias FileObjectClass = FileObject
    
-    public init? (baseURL: URL, credential: URLCredential, afterInitialized: SimpleCompletionHandler) {
+    public init? (baseURL: URL, credential: URLCredential?) {
        guard baseURL.uw_scheme.lowercased() == "smb" else {
            return nil
        }
-        self.baseURL = baseURL
-        dispatch_queue = DispatchQueue(label: "FileProvider.\(SMBFileProvider.type)", attributes: DispatchQueue.Attributes.concurrent)
-        //let url = baseURL.uw_absoluteString
+        self.baseURL = baseURL.appendingPathComponent("")
+        
+        #if swift(>=3.1)
+        let queueLabel = "FileProvider.\(Swift.type(of: self).type)"
+        #else
+        let queueLabel = "FileProvider.\(type(of: self).type)"
+        #endif
+        dispatch_queue = DispatchQueue(label: queueLabel, attributes: .concurrent)
+        operation_queue = OperationQueue()
+        operation_queue.name = "\(queueLabel).Operation"
+        
        self.credential = credential
    }
-        
+    
+    public required convenience init?(coder aDecoder: NSCoder) {
+        guard let baseURL = aDecoder.decodeObject(forKey: "baseURL") as? URL else {
+            return nil
+        }
+        self.init(baseURL: baseURL,
+                  credential: aDecoder.decodeObject(forKey: "credential") as? URLCredential)
+        self.currentPath   = aDecoder.decodeObject(forKey: "currentPath") as? String ?? ""
+    }
+    
+    open func encode(with aCoder: NSCoder) {
+        aCoder.encode(self.baseURL, forKey: "baseURL")
+        aCoder.encode(self.credential, forKey: "credential")
+        aCoder.encode(self.currentPath, forKey: "currentPath")
+    }
+    
+    public static var supportsSecureCoding: Bool {
+        return true
+    }
+    
    open func contentsOfDirectory(path: String, completionHandler: @escaping ((_ contents: [FileObjectClass], _ error: Error?) -> Void)) {
        NotImplemented()
    }
@@ -41,62 +68,62 @@ open class SMBFileProvider: FileProvider, FileProviderMonitor {
        NotImplemented()
    }
    
+    func isReachable(completionHandler: @escaping (Bool) -> Void) {
+        NotImplemented()
+    }
+    
    open weak var fileOperationDelegate: FileOperationDelegate?
    
-    open func create(folder folderName: String, at atPath: String, completionHandler: SimpleCompletionHandler) -> OperationHandle? {
+    open func create(folder folderName: String, at atPath: String, completionHandler: SimpleCompletionHandler) -> Progress? {
        NotImplemented()
        return nil
    }
    
-    open func create(file fileAttribs: FileObject, at atPath: String, contents data: Data?, completionHandler: SimpleCompletionHandler) -> OperationHandle? {
+    open func moveItem(path: String, to toPath: String, overwrite: Bool = false, completionHandler: SimpleCompletionHandler) -> Progress? {
        NotImplemented()
        return nil
    }
    
-    open func moveItem(path: String, to toPath: String, overwrite: Bool = false, completionHandler: SimpleCompletionHandler) -> OperationHandle? {
+    open func copyItem(path: String, to toPath: String, overwrite: Bool = false, completionHandler: SimpleCompletionHandler) -> Progress? {
        NotImplemented()
        return nil
    }
    
-    open func copyItem(path: String, to toPath: String, overwrite: Bool = false, completionHandler: SimpleCompletionHandler) -> OperationHandle? {
+    open func removeItem(path: String, completionHandler: SimpleCompletionHandler) -> Progress? {
        NotImplemented()
        return nil
    }
    
-    open func removeItem(path: String, completionHandler: SimpleCompletionHandler) -> OperationHandle? {
+    open func copyItem(localFile: URL, to toPath: String, overwrite: Bool, completionHandler: SimpleCompletionHandler) -> Progress? {
        NotImplemented()
        return nil
    }
    
-    open func copyItem(localFile: URL, to toPath: String, completionHandler: SimpleCompletionHandler) -> OperationHandle? {
+    open func copyItem(path: String, toLocalURL: URL, completionHandler: SimpleCompletionHandler) -> Progress? {
        NotImplemented()
        return nil
    }
    
-    open func copyItem(path: String, toLocalURL: URL, completionHandler: SimpleCompletionHandler) -> OperationHandle? {
+    open func contents(path: String, completionHandler: @escaping ((_ contents: Data?, _ error: Error?) -> Void)) -> Progress? {
        NotImplemented()
        return nil
    }
    
-    open func contents(path: String, completionHandler: @escaping ((_ contents: Data?, _ error: Error?) -> Void)) -> OperationHandle? {
+    open func contents(path: String, offset: Int64, length: Int, completionHandler: @escaping ((_ contents: Data?, _ error: Error?) -> Void)) -> Progress? {
        NotImplemented()
        return nil
    }
    
-    open func contents(path: String, offset: Int64, length: Int, completionHandler: @escaping ((_ contents: Data?, _ error: Error?) -> Void)) -> OperationHandle? {
+    open func writeContents(path: String, contents data: Data?, atomically: Bool, overwrite: Bool, completionHandler: SimpleCompletionHandler) -> Progress? {
        NotImplemented()
        return nil
    }
    
-    open func writeContents(path: String, contents data: Data, atomically: Bool, completionHandler: SimpleCompletionHandler) -> OperationHandle? {
+    open func searchFiles(path: String, recursive: Bool, query: NSPredicate, foundItemHandler:((FileObjectClass) -> Void)?, completionHandler: @escaping ((_ files: [FileObjectClass], _ error: Error?) -> Void)) -> Progress? {
        NotImplemented()
        return nil
    }
    
-    open func searchFiles(path: String, recursive: Bool, query: String, foundItemHandler:((FileObjectClass) -> Void)?, completionHandler: @escaping ((_ files: [FileObjectClass], _ error: Error?) -> Void)) {
-        NotImplemented()
-    }
-    
    open func registerNotifcation(path: String, eventHandler: @escaping (() -> Void)) {
        NotImplemented()
    }
@@ -108,10 +135,18 @@ open class SMBFileProvider: FileProvider, FileProviderMonitor {
    open func isRegisteredForNotification(path: String) -> Bool {
        return false
    }
+    
+    open func copy(with zone: NSZone? = nil) -> Any {
+        let copy = SMBFileProvider(baseURL: self.baseURL!, credential: self.credential!)!
+        copy.currentPath = self.currentPath
+        copy.delegate = self.delegate
+        copy.fileOperationDelegate = self.fileOperationDelegate
+        return copy
+    }
 }

 // MARK: basic CIFS interactivity
-public enum SMBFileProviderError: Int, Error, CustomStringConvertible {
+enum SMBFileProviderError: Int, Error, CustomStringConvertible {
    case badHeader
    case incompatibleHeader
    case incorrectParamsLength
@@ -8,17 +8,35 @@

 import Foundation

-protocol SMBRequest {
+protocol SMBRequestBody {
    func data() -> Data
 }

-protocol SMBResponse {
+extension SMBRequestBody {
+    func data() -> Data {
+        return Data(value: self)
+    }
+}
+
+protocol SMBResponseBody {
    init? (data: Data)
 }

+extension SMBResponseBody {
+    init? (data: Data) {
+        if let v: Self = data.scanValue() {
+            self = v
+        } else {
+            return nil
+        }
+    }
+}

-protocol IOCtlRequestProtocol: SMBRequest {}
-protocol IOCtlResponseProtocol: SMBResponse {}
+typealias SMBRequest = (header: SMB2.Header, body: SMBRequestBody?)
+typealias SMBResponse = (header: SMB2.Header, body: SMBResponseBody?)
+
+protocol IOCtlRequestProtocol: SMBRequestBody {}
+protocol IOCtlResponseProtocol: SMBResponseBody {}


 struct SMBTime {
@@ -11,7 +11,7 @@ import Foundation
 extension SMB2 {
    // MARK: SMB2 Create
    
-    struct CreateRequest: SMBRequest {
+    struct CreateRequest: SMBRequestBody {
        let header: CreateRequest.Header
        let name: String?
        let contexts: [CreateContext]
@@ -40,7 +40,7 @@ extension SMB2 {
                header.contextLength = 0
                //result.appendData(nameData)
            }
-            var result = encode(&header)
+            var result = Data(value: header)
            result.append(body)
            return result
        }
@@ -158,7 +158,7 @@ extension SMB2 {
        }
    }
    
-    struct CreateResponse: SMBResponse {
+    struct CreateResponse: SMBResponseBody {
        struct Header {
            let size: UInt16
            fileprivate let _oplockLevel: UInt8
@@ -186,7 +186,7 @@ extension SMB2 {
            guard data.count >= MemoryLayout<CreateResponse.Header>.size else {
                return nil
            }
-            self.header = decode(data)
+            self.header = data.scanValue()!
            if self.header.contextsOffset > 0 {
                var contexts = [CreateContext]()
                var contextOffset = Int(self.header.contextsOffset) - MemoryLayout<SMB2.Header>.size
@@ -195,14 +195,9 @@ extension SMB2 {
                        self.contexts = contexts
                        return
                    }
-                    let contextDataHeader = data.subdata(in: contextOffset..<(contextOffset + MemoryLayout<CreateContext.Header>.size))
-                    if let lastContextHeader = CreateContext(data: contextDataHeader) {
-                        let lastContextLen = Int(lastContextHeader.header.dataOffset) + Int(lastContextHeader.header.dataLength) - contextOffset
-                        let lastContextData = data.subdata(in: contextOffset..<(contextOffset + lastContextLen))
-                        if let newContext = CreateContext(data: lastContextData) {
-                            contexts.append(newContext)
-                        }
-                        contextOffset = Int(lastContextHeader.header.next) - MemoryLayout<SMB2.Header>.size
+                    while contextOffset > 0, let context: CreateContext = data.scanValue(start: contextOffset) {
+                        contexts.append(context)
+                        contextOffset = Int(context.header.next) - MemoryLayout<SMB2.Header>.size
                    }
                }
                self.contexts = contexts
@@ -232,9 +227,8 @@ extension SMB2 {
        }
        
        init(name: UUID, data: Data) {
-            var uuid = uuid_t(0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0)
-            (name as NSUUID).getBytes(&uuid.0)
-            var nameData = Data(bytes: &uuid.0, count: 16)
+            let uuid = name.uuid
+            var nameData = Data(value: uuid)
            self.header = CreateContext.Header(next: 0, nameOffset: 32, nameLength: UInt16(nameData.count), reserved: 0, dataOffset: UInt16(nameData.count), dataLength: UInt32(data.count))
            self.buffer = data
        }
@@ -244,12 +238,12 @@ extension SMB2 {
            guard data.count > headersize else {
                return nil
            }
-            self.header = decode(data)
+            self.header = data.scanValue()!
            self.buffer = data.subdata(in: headersize..<data.count)
        }
        
        func data() -> Data {
-            var result = encode(header)
+            var result = Data(value: header)
            result.append(buffer)
            return result
        }
@@ -363,7 +357,7 @@ extension SMB2 {
    
    // MARK: SMB2 Close
    
-    struct CloseRequest: SMBRequest {
+    struct CloseRequest: SMBRequestBody {
        let size: UInt16
        let flags: CloseFlags
        fileprivate let reserved2: UInt32
@@ -377,13 +371,9 @@ extension SMB2 {
            self.flags = []
            self.reserved2 = 0
        }
-        
-        func data() -> Data {
-            return encode(self)
-        }
    }
    
-    struct CloseResponse: SMBResponse {
+    struct CloseResponse: SMBResponseBody {
        let size: UInt16
        let flags: CloseFlags
        fileprivate let reserved: UInt32
@@ -394,10 +384,6 @@ extension SMB2 {
        let allocationSize: UInt64
        let endOfFile: UInt64
        let fileAttributes: FileAttributes
-        
-        init? (data: Data) {
-            self = decode(data)
-        }
    }
    
    struct CloseFlags: OptionSet {
@@ -412,7 +398,7 @@ extension SMB2 {
    
    // MARK: SMB2 Flush
    
-    struct FlushRequest: SMBRequest {
+    struct FlushRequest: SMBRequestBody {
        let size: UInt16
        fileprivate let reserved: UInt16
        fileprivate let reserved2: UInt32
@@ -426,13 +412,9 @@ extension SMB2 {
            self.reserved = 0
            self.reserved2 = 0
        }
-        
-        func data() -> Data {
-            return encode(self)
-        }
    }
    
-    struct FlushResponse: SMBResponse {
+    struct FlushResponse: SMBResponseBody {
        let size: UInt16
        let reserved: UInt16
        
@@ -440,9 +422,5 @@ extension SMB2 {
            self.size = 4
            self.reserved = 0
        }
-        
-        init? (data: Data) {
-            self = decode(data)
-        }
    }
 }
@@ -11,7 +11,7 @@ import Foundation
 extension SMB2 {
    // MARK: SMB2 Read
    
-    struct ReadRequest: SMBRequest {
+    struct ReadRequest: SMBRequestBody {
        let size: UInt16
        fileprivate let padding: UInt8
        let flags: ReadRequest.Flags
@@ -43,10 +43,6 @@ extension SMB2 {
            self.channelBuffer = 0
        }
        
-        func data() -> Data {
-            return encode(read)
-        }
-        
        struct Flags: OptionSet {
            let rawValue: UInt8
            
@@ -58,7 +54,7 @@ extension SMB2 {
        }
    }
    
-    struct ReadRespone: SMBResponse {
+    struct ReadRespone: SMBResponseBody {
        struct Header {
            let size: UInt16
            let offset: UInt8
@@ -75,7 +71,7 @@ extension SMB2 {
            guard data.count > 16 else {
                return nil
            }
-            self.header = decode(data)
+            self.header = data.scanValue()!
            let headersize = MemoryLayout<Header>.size
            self.buffer = data.subdata(in: headersize..<data.count)
        }
@@ -89,7 +85,7 @@ extension SMB2 {
    
    // MARK: SMB2 Write
    
-    struct WriteRequest: SMBRequest {
+    struct WriteRequest: SMBRequestBody {
        let header: WriteRequest.Header
        let channelInfo: ChannelInfo?
        let fileData: Data
@@ -110,6 +106,7 @@ extension SMB2 {
            let flags: WriteRequest.Flags
        }
        
+        // codebeat:disable[ARITY]
        init(fileId: FileId, offset: UInt64, remainingBytes: UInt32 = 0, data: Data, channel: Channel = .NONE, channelInfo: ChannelInfo? = nil, flags: WriteRequest.Flags = []) {
            var channelInfoOffset: UInt16 = 0
            var channelInfoLength: UInt16 = 0
@@ -122,9 +119,10 @@ extension SMB2 {
            self.channelInfo = channelInfo
            self.fileData = data
        }
+        // codebeat:enable[ARITY]
        
        func data() -> Data {
-            var result = encode(self.header)
+            var result = Data(value: self.header)
            if let channelInfo = channelInfo {
                result.append(channelInfo.data())
            }
@@ -144,41 +142,29 @@ extension SMB2 {
        }
    }
    
-    struct WriteResponse: SMBResponse {
+    struct WriteResponse: SMBResponseBody {
        let size: UInt16
        fileprivate let reserved: UInt16
        let writtenBytes: UInt32
        fileprivate let remaining: UInt32
        fileprivate let channelInfoOffset: UInt16
        fileprivate let channelInfoLength: UInt16
-        
-        init?(data: Data) {
-            self = decode(data)
-        }
    }
    
-    struct ChannelInfo: SMBRequest {
+    struct ChannelInfo: SMBRequestBody {
        let offset: UInt64
        let token: UInt32
        let length: UInt32
-        
-        func data() -> Data {
-            return encode(data)
-        }
    }
    
    // MARK: SMB2 Lock
    
-    struct LockElement: SMBRequest {
+    struct LockElement: SMBRequestBody {
        let offset: UInt64
        let length: UInt64
        let flags: LockElement.Flags
        fileprivate let reserved: UInt32
        
-        func data() -> Data {
-            return encode(self)
-        }
-        
        struct Flags: OptionSet {
            let rawValue: UInt32
            
@@ -193,7 +179,7 @@ extension SMB2 {
        }
    }
    
-    struct LockRequest: SMBRequest {
+    struct LockRequest: SMBRequestBody {
        let header: LockRequest.Header
        let locks: [LockElement]
        
@@ -203,9 +189,9 @@ extension SMB2 {
        }
        
        func data() -> Data {
-            var result = encode(header)
+            var result = Data(value: header)
            for lock in locks {
-                result.append(encode(lock))
+                result.append(Data(value: lock))
            }
            return result
        }
@@ -218,7 +204,7 @@ extension SMB2 {
        }
    }
    
-    struct LockResponse: SMBResponse {
+    struct LockResponse: SMBResponseBody {
        let size: UInt16
        let reserved: UInt16
        
@@ -226,15 +212,11 @@ extension SMB2 {
            self.size = 4
            self.reserved = 0
        }
-        
-        init? (data: Data) {
-            self = decode(data)
-        }
    }
    
    // MARK: SMB2 Cancel
    
-    struct CancelRequest: SMBRequest {
+    struct CancelRequest: SMBRequestBody {
        let size: UInt16
        let reserved: UInt16
        
@@ -242,9 +224,5 @@ extension SMB2 {
            self.size = 4
            self.reserved = 0
        }
-        
-        func data() -> Data {
-            return encode(self)
-        }
    }
 }
@@ -15,7 +15,7 @@ extension SMB2 {
     * IOCtl usage is usually limited in SMB to pipe requests and duplicating file inside server
     */
    
-    struct IOCtlRequest: SMBRequest {
+    struct IOCtlRequest: SMBRequestBody {
        let header: Header
        let requestData:  IOCtlRequestProtocol?
        
@@ -26,7 +26,7 @@ extension SMB2 {
        }
        
        func data() -> Data {
-            var result = encode(self.header)
+            var result = Data(value: self.header)
            if let reqData = requestData?.data() {
                result.append(reqData)
            }
@@ -63,12 +63,12 @@ extension SMB2 {
        }
    }
    
-    struct IOCtlResponse: SMBResponse {
+    struct IOCtlResponse: SMBResponseBody {
        let header: Header
        let responseData:  IOCtlResponseProtocol?
        
        init?(data: Data) {
-            self.header = decode(data)
+            self.header = data.scanValue()!
            let endRange = Int(self.header.outputOffset - 64) + Int(self.header.outputCount)
            let response = data.subdata(in: Int(self.header.outputOffset - 64)..<endRange)
            switch self.header.ctlCode {
@@ -140,10 +140,10 @@ extension SMB2 {
            let chunks: [Chunk]
            
            func data() -> Data {
-                var result = encode(sourceKey)
-                result.append(encode(chunkCount))
-                var reserved: UInt32 = 0
-                result.append(encode(&reserved))
+                var result = Data(value: sourceKey)
+                result.append(Data(value: chunkCount))
+                let reserved: UInt32 = 0
+                result.append(Data(value: reserved))
                return Data()
            }
            
@@ -152,10 +152,6 @@ extension SMB2 {
                let targetOffset: UInt64
                let length: UInt32
                fileprivate let reserved: UInt32
-                
-                func data() -> Data {
-                    return encode(self)
-                }
            }
        }
        
@@ -182,10 +178,6 @@ extension SMB2 {
                self.length = length
                self.offset = offset
            }
-            
-            func data() -> Data {
-                return encode(self)
-            }
        }
        
        struct ResilencyRequest: IOCtlRequestProtocol {
@@ -197,10 +189,6 @@ extension SMB2 {
                self.timeout = timeout
                self.reserved = 0
            }
-            
-            func data() -> Data {
-                return encode(self)
-            }
        }
        
        struct ValidateNegotiateInfo: IOCtlRequestProtocol {
@@ -213,8 +201,8 @@ extension SMB2 {
            }
            
            func data() -> Data {
-                var result = encode(self.header)
-                dialects.forEach { result.append(encode($0)) }
+                var result = Data(value: self.header)
+                dialects.forEach { result.append(Data(value: $0)) }
                return result
            }
            
@@ -234,10 +222,6 @@ extension SMB2 {
            let chunksCount: UInt32
            let chunksBytesWritten: UInt32
            let totalBytesWriiten: UInt32
-            
-            init?(data: Data) {
-                self = decode(data)
-            }
        }
        
        // SRV_ENUMERATE_SNAPSHOTS
@@ -247,8 +231,9 @@ extension SMB2 {
            let snapshots: [SMBTime]
            
            init?(data: Data) {
-                self.count = decode(data)
-                self.returnedCount = decode(data.subdata(in: 4..<8))
+                guard data.count > 8 else { return nil }
+                self.count = data.scanValue()!
+                self.returnedCount = data.scanValue(start: 4)!
                //let size: UInt32 = decode(data.subdataWithRange(NSRange(location: 8, length: 4)))
                var snapshots = [SMBTime]()
                let dateFormatter = DateFormatter()
@@ -258,7 +243,7 @@ extension SMB2 {
                    if data.count < offset + 48 {
                        return nil
                    }
-                    let datestring = String(data: data.subdata(in: offset..<(offset + 48)), encoding: .utf16)
+                    let datestring = data.scanString(start: offset, length: 48, using: .utf16)
                    if let datestring = datestring, let date = dateFormatter.date(from: datestring) {
                        snapshots.append(SMBTime(date: date))
                    }
@@ -271,32 +256,21 @@ extension SMB2 {
            let key: (UInt64, UInt64, UInt64)
            fileprivate let contextLength: UInt32
            fileprivate let context: UInt32
-            
-            init?(data: Data) {
-                self = decode(data)
-            }
        }
        
        struct ReadHash: IOCtlResponseProtocol {
            // TODO: Implement IOCTL READ_HASH
-            
-            init?(data: Data) {
-                self = decode(data)
-            }
        }
        
        struct NetworkInterfaceInfo: IOCtlResponseProtocol {
            let items: [NetworkInterfaceInfo.Item]
            
            init?(data: Data) {
-                let count = data.count / MemoryLayout<Item>.size
-                guard count > 0 else {
-                    return nil
-                }
                var items = [Item]()
-                for i in 0..<count {
-                    let itemdata = data.subdata(in: (i * MemoryLayout<Item>.size)..<((i + 1) * MemoryLayout<Item>.size))
-                    items.append(decode(itemdata))
+                var offset = 0
+                while let item: Item = data.scanValue(start: offset) {
+                    items.append(item)
+                    offset += MemoryLayout<Item>.size
                }
                self.items = items
            }
@@ -335,15 +309,11 @@ extension SMB2 {
                static let ipv6: sa_family_t = 0x17
                
                var sockaddr: sockaddr_in {
-                    var sockaddrStorage = self.sockaddrStorage
-                    let data = Data(bytes: &sockaddrStorage, count: 16)
-                    return decode(data)
+                    return Data.mapMemory(from: self.sockaddrStorage)!
                }
                
                var sockaddr6: sockaddr_in6 {
-                    var sockaddrStorage = self.sockaddrStorage
-                    let data = Data(bytes: &sockaddrStorage, count: 28)
-                    return decode(data)
+                     return Data.mapMemory(from: self.sockaddrStorage)!
                }
            }
        }
@@ -356,10 +326,6 @@ extension SMB2 {
            var dialect: (major: Int, minor: Int) {
                return (major: Int(_dialect & 0xFF), minor: Int(_dialect >> 8))
            }
-            
-            init?(data: Data) {
-                self = decode(data)
-            }
        }
    }
    
@@ -11,7 +11,7 @@ import Foundation
 extension SMB2 {
    // MARK: SMB2 Change Notify
    
-    struct ChangeNotifyRequest: SMBRequest {
+    struct ChangeNotifyRequest: SMBRequestBody {
        let size: UInt16
        let flags: ChangeNotifyRequest.Flags
        let outputBufferLength: UInt32
@@ -28,10 +28,6 @@ extension SMB2 {
            self.reserved = 0
        }
        
-        func data() -> Data {
-            return encode(self)
-        }
-        
        struct Flags: OptionSet {
            let rawValue: UInt16
            
@@ -79,7 +75,7 @@ extension SMB2 {
        }
    }
    
-    struct ChangeNotifyResponse: SMBResponse {
+    struct ChangeNotifyResponse: SMBResponseBody {
        let notifications: [(action: FileNotifyAction, fileName: String)]
        
        init?(data: Data) {
@@ -89,19 +85,14 @@ extension SMB2 {
            
            var offset = 0
            while i < maxLoop {
-                let nextOffsetData = data.subdata(in: offset..<(offset + 4))
-                let nextOffset: UInt32 = decode(nextOffsetData)
-                
-                let actionData = data.subdata(in: (offset + 4)..<(offset + 8))
-                let actionValue: UInt32 = decode(actionData)
+                let nextOffset: UInt32 = data.scanValue(start: offset) ?? 0
+                let actionValue: UInt32 = data.scanValue(start: offset + 4) ?? 0
                guard let action = FileNotifyAction(rawValue: actionValue) else {
                    continue
                }
                
-                let fileLenData = data.subdata(in: (offset + 8)..<(offset + 12))
-                let fileNameLen = Int(decode(fileLenData) as UInt32)
-                let fileNameData = data.subdata(in: (offset + 12)..<(offset + 12 + fileNameLen))
-                let fileName = String(data: fileNameData, encoding: .utf16) ?? ""
+                let fileNameLen = Int(data.scanValue(start: offset + 8) as UInt32? ?? 0)
+                let fileName = data.scanString(start: offset + 12, length: fileNameLen, using: .utf16) ?? ""
                result.append((action: action, fileName: fileName))
                
                offset += Int(nextOffset)
@@ -11,7 +11,7 @@ import Foundation
 extension SMB2 {
    // MARK: SMB2 Query Directory
    
-    struct QueryDirectoryRequest: SMBRequest {
+    struct QueryDirectoryRequest: SMBRequestBody {
        let header: QueryDirectoryRequest.Header
        let searchPattern: String?
        
@@ -28,7 +28,7 @@ extension SMB2 {
        }
        
        func data() -> Data {
-            var result = encode(header)
+            var result = Data(value: header)
            if let patternData = searchPattern?.data(using: .utf16) {
                result.append(patternData)
            }
@@ -60,7 +60,7 @@ extension SMB2 {
        }
    }
    
-    struct QueryDirectoryResponse: SMBResponse {
+    struct QueryDirectoryResponse: SMBResponseBody {
        let buffer: Data
        
        func parseAs(type: FileInformationEnum) -> [(header: SMB2FilesInformationHeader, fileName: String)] {
@@ -68,43 +68,24 @@ extension SMB2 {
            var result = [(header: SMB2FilesInformationHeader, fileName: String)]()
            while true {
                let header: SMB2FilesInformationHeader
-                let headersize: Int
                switch type {
                case .fileDirectoryInformation:
-                    headersize = MemoryLayout<FileDirectoryInformationHeader>.size
-                    let headerData = buffer.subdata(in: offset..<(offset + headersize))
-                    let h: FileDirectoryInformationHeader = decode(headerData)
-                    header = h
+                    header = buffer.scanValue(start: offset) as FileDirectoryInformationHeader!
                case .fileFullDirectoryInformation:
-                    headersize = MemoryLayout<FileFullDirectoryInformationHeader>.size
-                    let headerData = buffer.subdata(in: offset..<(offset + headersize))
-                    let h: FileFullDirectoryInformationHeader = decode(headerData)
-                    header = h
+                    header = buffer.scanValue(start: offset) as FileFullDirectoryInformationHeader!
                case .fileIdFullDirectoryInformation:
-                    headersize = MemoryLayout<FileIdFullDirectoryInformationHeader>.size
-                    let headerData = buffer.subdata(in: offset..<(offset + headersize))
-                    let h: FileIdFullDirectoryInformationHeader = decode(headerData)
-                    header = h
+                    header = buffer.scanValue(start: offset) as FileIdFullDirectoryInformationHeader!
                case .fileBothDirectoryInformation:
-                    headersize = MemoryLayout<FileBothDirectoryInformationHeader>.size
-                    let headerData = buffer.subdata(in: offset..<(offset + headersize))
-                    let h: FileBothDirectoryInformationHeader = decode(headerData)
-                    header = h
+                    header = buffer.scanValue(start: offset) as FileBothDirectoryInformationHeader!
                case .fileIdBothDirectoryInformation:
-                    headersize = MemoryLayout<FileIdBothDirectoryInformationHeader>.size
-                    let headerData = buffer.subdata(in: offset..<(offset + headersize))
-                    let h: FileIdBothDirectoryInformationHeader = decode(headerData)
-                    header = h
+                    header = buffer.scanValue(start: offset) as FileIdBothDirectoryInformationHeader!
                case .fileNamesInformation:
-                    headersize = MemoryLayout<FileNamesInformationHeader>.size
-                    let headerData = buffer.subdata(in: offset..<(offset + headersize))
-                    let h: FileNamesInformationHeader = decode(headerData)
-                    header = h
+                    header = buffer.scanValue(start: offset) as FileNamesInformationHeader!
                default:
                    return []
                }
-                let fnData = buffer.subdata(in: (offset + headersize)..<(offset + headersize + Int(header.fileNameLength)))
-                let fileName = String(data: fnData, encoding: .utf16) ?? ""
+                let headersize = MemoryLayout.size(ofValue: header)
+                let fileName = buffer.scanString(start: headersize, length: Int(header.fileNameLength), using: .utf16) ?? ""
                result.append((header: header, fileName: fileName))
                if header.nextEntryOffset == 0 {
                    break
@@ -115,8 +96,8 @@ extension SMB2 {
        }
        
        init? (data: Data) {
-            let offset = Int(decode(data.subdata(in: 2..<4)) as UInt16)
-            let length = Int(decode(data.subdata(in: 4..<8)) as UInt32)
+            let offset = Int(data.scanValue(start: 2) as UInt16!)
+            let length = Int(data.scanValue(start: 4) as UInt32!)
            guard data.count > offset + length else {
                return nil
            }
@@ -126,7 +107,7 @@ extension SMB2 {
    
    // MARK: SMB2 Query Info
    
-    struct QueryInfoRequest: SMBRequest {
+    struct QueryInfoRequest: SMBRequestBody {
        let header: Header
        let buffer: Data?
        
@@ -143,8 +124,8 @@ extension SMB2 {
                }
                let strLength = UInt8(strData.count)
                let nextOffset = UInt32(4 + 1 + strData.count)
-                var data = encode(nextOffset)
-                data.append(encode(strLength))
+                var data = Data(value: nextOffset)
+                data.append(Data(value: strLength))
                data.append(strData)
                data.count += 1
                let padSize = (data.count) % 4
@@ -170,8 +151,7 @@ extension SMB2 {
        // TODO: Implement QUOTA_INFO init
        
        func data() -> Data {
-            let headerData = encode(header)
-            var result = headerData
+            var result = Data(value: header)
            if let buffer = buffer {
                result.append(buffer)
            }
@@ -204,12 +184,11 @@ extension SMB2 {
        }
    }
    
-    struct QueryInfoResponse: SMBResponse {
+    struct QueryInfoResponse: SMBResponseBody {
        let buffer: Data
        
        init?(data: Data) {
-            let structSizeData = data.subdata(in: 0..<2)
-            let structSize: UInt16 = decode(structSizeData)
+            let structSize: UInt16 = data.scanValue()!
            guard structSize == 9 else {
                return nil
            }
@@ -217,10 +196,9 @@ extension SMB2 {
            /*let offsetData = data.subdataWithRange(NSRange(location: 2, length: 2))
            let offset: UInt16 = decode(offsetData)*/
            
-            let lengthData = data.subdata(in: 4..<8)
-            let length = Int(decode(lengthData) as UInt32)
+            let length = Int(data.scanValue(start: 4) as UInt32!)
            
-            guard data.count >= 8 + Int(length) else {
+            guard data.count >= 8 + length else {
                return nil
            }
            
@@ -228,40 +206,38 @@ extension SMB2 {
        }
        
        var asAccessInformation: FileAccessInformation {
-            return decode(buffer)
+            return buffer.scanValue()!
        }
        
        var asAlignmentInformation: FileAlignmentInformation {
-            return decode(buffer)
+            return buffer.scanValue()!
        }
        
        var asAllInformation: (header: FileAllInformationHeader, name: String) {
-            let header: FileAllInformationHeader = decode(buffer)
+            let header: FileAllInformationHeader = buffer.scanValue()!
            let headersize = MemoryLayout<FileAllInformationHeader>.size
-            let nameData = buffer.subdata(in: headersize..<(headersize + Int(header.nameLength)))
-            let name = String(data: nameData, encoding: .utf16) ?? ""
+            let name = buffer.scanString(start: headersize, length: Int(header.nameLength), using: .utf16) ?? ""
            return (header, name)
        }
        
        var asAlternateNameInformation: String {
-            let b = (buffer as NSData).bytes.bindMemory(to: CChar.self, capacity: buffer.count)
-            return String(cString: b, encoding: .utf16) ?? ""
+            return buffer.scanString(start: 0, length: buffer.count, using: .utf16) ?? ""
        }
        
        var asAttributeTagInformation: FileAttributeTagInformation {
-            return decode(buffer)
+            return buffer.scanValue()!
        }
        
        var asBasicInformation: FileBasicInformation {
-            return decode(buffer)
+            return buffer.scanValue()!
        }
        
        var asCompressionInformation: FileCompressionInformation {
-            return decode(buffer)
+            return buffer.scanValue()!
        }
        
        var asEaInformation: FileEaInformation {
-            return decode(buffer)
+            return buffer.scanValue()!
        }
        
        var asFullEaInformation: FileFullEaInformation {
@@ -270,83 +246,80 @@ extension SMB2 {
        }
        
        var asInternalInformation: FileInternalInformation {
-            return decode(buffer)
+            return buffer.scanValue()!
        }
        
        var asModeInformation: FileModeInformation {
-            return decode(buffer)
+            return buffer.scanValue()!
        }
        
        var asNetworkOpenInformation: FileNetworkOpenInformation {
-            return decode(buffer)
+            return buffer.scanValue()!
        }
        
        var asPipeInformation: FilePipeInformation {
-            return decode(buffer)
+            return buffer.scanValue()!
        }
        
        var asPipeLocalInformation: FilePipeLocalInformation {
-            return decode(buffer)
+            return buffer.scanValue()!
        }
        
        var asPipeRemoteInformation: FilePipeRemoteInformation {
-            return decode(buffer)
+            return buffer.scanValue()!
        }
        
        var asPositionInformation: FilePositionInformation {
-            return decode(buffer)
+            return buffer.scanValue()!
        }
        
        var asStandardInformation: FileStandardInformation {
-            return decode(buffer)
+            return buffer.scanValue()!
        }
        
        var asStreamInformation: (header: FileStreamInformationHeader, name: String) {
-            let header: FileStreamInformationHeader = decode(buffer)
+            let header: FileStreamInformationHeader = buffer.scanValue()!
            let headersize = MemoryLayout<FileStreamInformationHeader>.size
-            let nameData = buffer.subdata(in: headersize..<(headersize + Int(header.streamNameLength)))
-            let name = String(data: nameData, encoding: .utf16) ?? ""
+            let name = buffer.scanString(start: headersize, length: Int(header.streamNameLength), using: .utf16) ?? ""
            return (header, name)
        }
        
        var asFsVolumeInformation: (header: FileFsVolumeInformationHeader, name: String) {
-            let header: FileFsVolumeInformationHeader = decode(buffer)
+            let header: FileFsVolumeInformationHeader = buffer.scanValue()!
            let headersize = MemoryLayout<FileFsVolumeInformationHeader>.size
-            let nameData = buffer.subdata(in: headersize..<(headersize + Int(header.labelLength)))
-            let name = String(data: nameData, encoding: .utf16) ?? ""
+            let name = buffer.scanString(start: headersize, length: Int(header.labelLength), using: .utf16) ?? ""
            return (header, name)
        }
        
        var asFsSizeInformation: FileFsSizeInformation {
-            return decode(buffer)
+            return buffer.scanValue()!
        }
        
        var asFsDeviceInformation: FileFsDeviceInformation {
-            return decode(buffer)
+            return buffer.scanValue()!
        }
        
        var asFsAttributeInformation: (header: FileFsAttributeInformationHeader, name: String) {
-            let header: FileFsAttributeInformationHeader = decode(buffer)
+            let header: FileFsAttributeInformationHeader = buffer.scanValue()!
            let headersize = MemoryLayout<FileFsAttributeInformationHeader>.size
-            let nameData = buffer.subdata(in: headersize..<(headersize + Int(header.nameLength)))
-            let name = String(data: nameData, encoding: .utf16) ?? ""
+            let name = buffer.scanString(start: headersize, length: Int(header.nameLength), using: .utf16) ?? ""
            return (header, name)
        }
        
        var asFsControlInformation: FileFsControlInformation {
-            return decode(buffer)
+            return buffer.scanValue()!
        }
        
        var asFsFullSizeInformation: FileFsFullSizeInformation {
-            return decode(buffer)
+            return buffer.scanValue()!
        }
        
        var asFsObjectIdInformation: FileFsObjectIdInformation {
-            return decode(buffer)
+            return buffer.scanValue()!
        }
        
        var asFsSectorSizeInformation: FileFsSectorSizeInformation {
-            return decode(buffer)
+            return buffer.scanValue()!
        }
    }
 }
@@ -8,7 +8,7 @@

 import Foundation

-protocol SMB2FilesInformationHeader: SMBResponse {
+protocol SMB2FilesInformationHeader: SMBResponseBody {
    var nextEntryOffset: UInt32 { get }
    var fileIndex: UInt32 { get }
    var fileNameLength : UInt32 { get }
@@ -127,10 +127,6 @@ extension SMB2 {
        let allocationSize: UInt64
        let fileAttributes: FileAttributes
        let fileNameLength : UInt32
-        
-        init?(data: Data) {
-            self = decode(data)
-        }
    }
    
    struct FileFullDirectoryInformationHeader: SMB2FilesInformationHeader {
@@ -145,10 +141,6 @@ extension SMB2 {
        let fileAttributes: FileAttributes
        let fileNameLength : UInt32
        let extendedAttributesSize: UInt32
-        
-        init?(data: Data) {
-            self = decode(data)
-        }
    }
    
    struct FileIdFullDirectoryInformationHeader: SMB2FilesInformationHeader {
@@ -165,10 +157,6 @@ extension SMB2 {
        let extendedAttributesSize: UInt32
        fileprivate let reserved: UInt32
        let fileId: FileId
-        
-        init?(data: Data) {
-            self = decode(data)
-        }
    }
    
    struct FileBothDirectoryInformationHeader: SMB2FilesInformationHeader {
@@ -187,14 +175,9 @@ extension SMB2 {
        fileprivate let reserved: UInt8
        fileprivate let _shortName: FileShortNameType
        var shortName: String? {
-            let s = encode(_shortName)
-            var d = s
-            d.count = Int(shortNameLen)
-            return String(data: d, encoding: .utf16)
-        }
-        
-        init?(data: Data) {
-            self = decode(data)
+            var data = Data(value: _shortName)
+            data.count = Int(shortNameLen)
+            return String(data: data, encoding: .utf16)
        }
    }
    
@@ -214,27 +197,18 @@ extension SMB2 {
        fileprivate let reserved: UInt8
        fileprivate let _shortName: FileShortNameType
        var shortName: String? {
-            let s = encode(_shortName)
-            var d = s
-            d.count = Int(shortNameLen)
-            return String(data: d, encoding: .utf16)
+            var data = Data(value: _shortName)
+            data.count = Int(shortNameLen)
+            return String(data: data, encoding: .utf16)
        }
        fileprivate let reserved2: UInt16
        let fileId : FileId
-        
-        init?(data: Data) {
-            self = decode(data)
-        }
    }
    
    struct FileNamesInformationHeader: SMB2FilesInformationHeader {
        let nextEntryOffset: UInt32
        let fileIndex: UInt32
        let fileNameLength : UInt32
-        
-        init?(data: Data) {
-            self = decode(data)
-        }
    }
    
    typealias FileShortNameType = (UInt8, UInt8, UInt8, UInt8, UInt8, UInt8, UInt8, UInt8,
@@ -11,7 +11,7 @@ import Foundation
 extension SMB2 {
    // MARK: SMB2 Negotiating
    
-    struct NegotiateRequest: SMBRequest {
+    struct NegotiateRequest: SMBRequestBody {
        let header: NegotiateRequest.Header
        let dialects: [UInt16]
        let contexts: [(type: NegotiateContextType, data: Data)]
@@ -43,13 +43,11 @@ extension SMB2 {
            
            var contextData = Data()
            for context in contexts {
-                var contextType = context.type.rawValue
-                contextData.append(UnsafeBufferPointer(start: &contextType, count: 2))
-                var dataLen = UInt16(context.data.count)
+                contextData.append(Data(value: context.type.rawValue))
                contextData.count += 4
-                contextData.append(UnsafeBufferPointer(start: &dataLen, count: 2))
+                contextData.append(Data(value: UInt16(context.data.count)))
            }
-            var result = encode(&header)
+            var result = Data(value: header)
            result.append(dialectData as Data)
            result.append(contextData as Data)
            return result
@@ -91,16 +89,16 @@ extension SMB2 {
        }
    }
    
-    struct NegotiateResponse: SMBResponse {
+    struct NegotiateResponse: SMBResponseBody {
        let header: NegotiateResponse.Header
        let buffer: Data?
        let contexts: [(type: NegotiateContextType, data: Data)]
        
        init? (data: Data) {
-            if data.count < 64 {
+            guard data.count >= 64 else {
                return nil
            }
-            self.header = decode(data)
+            self.header = data.scanValue()!
            if Int(header.size) != 65 {
                return nil
            }
@@ -176,7 +174,7 @@ extension SMB2 {
    
    // MARK: SMB2 Session Setup
    
-    struct SessionSetupRequest: SMBRequest {
+    struct SessionSetupRequest: SMBRequestBody {
        let header: SessionSetupRequest.Header
        let buffer: Data?
        
@@ -194,7 +192,7 @@ extension SMB2 {
            var header = self.header
            header.bufferOffset = UInt16(MemoryLayout<SMB2.Header>.size + MemoryLayout<SessionSetupRequest.Header>.size)
            header.bufferLength = UInt16(buffer?.count ?? 0)
-            var result = encode(&header)
+            var result = Data(value: header)
            if let buffer = self.buffer {
                result.append(buffer)
            }
@@ -235,15 +233,15 @@ extension SMB2 {
        }
    }
    
-    struct SessionSetupResponse: SMBResponse {
+    struct SessionSetupResponse: SMBResponseBody {
        let header: SessionSetupResponse.Header
        let buffer: Data?
        
        init? (data: Data) {
-            if data.count < 64 {
+            guard data.count >= 64 else {
                return nil
            }
-            self.header = decode(data)
+            self.header = data.scanValue()!
            if Int(header.size) != 9 {
                return nil
            }
@@ -289,7 +287,7 @@ extension SMB2 {
    
    // MARK: SMB2 Log off
    
-    struct LogOff: SMBRequest, SMBResponse {
+    struct LogOff: SMBRequestBody, SMBResponseBody {
        let size: UInt16
        let reserved: UInt16
        
@@ -297,19 +295,11 @@ extension SMB2 {
            self.size = 4
            self.reserved = 0
        }
-        
-        init? (data: Data) {
-            self = decode(data)
-        }
-        
-        func data() -> Data {
-            return encode(self)
-        }
    }
    
    // MARK: SMB2 Echo
    
-    struct Echo: SMBRequest, SMBResponse {
+    struct Echo: SMBRequestBody, SMBResponseBody {
        let size: UInt16
        let reserved: UInt16
        
@@ -317,13 +307,5 @@ extension SMB2 {
            self.size = 4
            self.reserved = 0
        }
-        
-        init? (data: Data) {
-            self = decode(data)
-        }
-        
-        func data() -> Data {
-            return encode(self)
-        }
    }
 }
@@ -10,14 +10,14 @@ import Foundation

 extension SMB2 {
    // MARK: SMB2 Set Info
-    struct SetInfoRequest: SMBRequest {
+    struct SetInfoRequest: SMBRequestBody {
        let header: Header
        let buffer: Data?
        
-        
-        
        func data() -> Data {
-            return Data()
+            var result = Data(value: header)
+            result.append(buffer ?? Data())
+            return result 
        }
        
        struct Header {
@@ -32,15 +32,11 @@ extension SMB2 {
        }
    }
    
-    struct SetInfoResponse: SMBResponse {
+    struct SetInfoResponse: SMBResponseBody {
        let size: UInt16
        
        init() {
            self.size = 2
        }
-        
-        init? (data: Data) {
-            self = decode(data)
-        }
    }
 }
@@ -11,7 +11,7 @@ import Foundation
 extension SMB2 {
    // MARK: SMB2 Tree Connect
    
-    struct TreeConnectRequest: SMBRequest {
+    struct TreeConnectRequest: SMBRequestBody {
        let header: TreeConnectRequest.Header
        let buffer: Data?
        var path: String {
@@ -34,7 +34,7 @@ extension SMB2 {
            var header = self.header
            header.pathOffset = UInt16(MemoryLayout<SMB2.Header>.size + MemoryLayout<TreeConnectRequest.Header>.size)
            header.pathLength = UInt16(buffer?.count ?? 0)
-            var result = encode(&header)
+            var result = Data(value: header)
            if let buffer = self.buffer {
                result.append(buffer)
            }
@@ -66,7 +66,7 @@ extension SMB2 {
        }
    }
    
-    struct TreeConnectResponse: SMBResponse {
+    struct TreeConnectResponse: SMBResponseBody {
        let size: UInt16  // = 16
        fileprivate let _type: UInt8
        var type: ShareType {
@@ -77,13 +77,6 @@ extension SMB2 {
        let capabilities: TreeConnectResponse.Capabilities
        let maximalAccess: FileAccessMask
        
-        init? (data: Data) {
-            if data.count != 16 {
-                return nil
-            }
-            self = decode(data)
-        }
-        
        enum ShareType: UInt8 {
            case UNKNOWN  = 0x00
            case DISK     = 0x01
@@ -131,7 +124,7 @@ extension SMB2 {
    
    // MARK: SMB2 Tree Disconnect
    
-    struct TreeDisconnect: SMBRequest, SMBResponse {
+    struct TreeDisconnect: SMBRequestBody, SMBResponseBody {
        let size: UInt16
        let reserved: UInt16
        
@@ -139,13 +132,5 @@ extension SMB2 {
            self.size = 4
            self.reserved = 0
        }
-        
-        init? (data: Data) {
-            self = decode(data)
-        }
-        
-        func data() -> Data {
-            return encode(self)
-        }
    }
 }
@@ -8,24 +8,6 @@

 import Foundation

-internal func encode<T>(_ value: inout T) -> Data {
-    return withUnsafePointer(to: &value) { p in
-        Data(bytes: p, count: MemoryLayout.size(ofValue: value))
-    }
-}
-
-internal func encode<T>(_ value: T) -> Data {
-    var value = value
-    return encode(&value)
-}
-
-internal func decode<T>(_ data: Data) -> T {
-    let pointer = UnsafeMutablePointer<T>.allocate(capacity: MemoryLayout<T.Type>.size)
-    (data as NSData).getBytes(pointer, length: MemoryLayout<T.Type>.size)
-    
-    return pointer.move()
-}
-
 protocol FileProviderSMBHeader {
    var protocolID: UInt32 { get }
    static var protocolConst: UInt32 { get }
@@ -10,7 +10,7 @@ import Foundation

 /// Error Types and Description

-public enum NTStatus: UInt32, Error, CustomStringConvertible {
+enum NTStatus: UInt32, Error, CustomStringConvertible {
    case SUCCESS                        = 0x00000000
    case NOT_IMPLEMENTED                = 0xC0000002
    case INVALID_DEVICE_REQUEST         = 0xC0000010
@@ -7,118 +7,145 @@
 //

 import Foundation
+import CoreGraphics

-public final class WebDavFileObject: FileObject {
-    public let contentType: String
-    public let entryTag: String?
+/**
+ Allows accessing to WebDAV server files. This provider doesn't cache or save files internally, however you can
+ set `useCache` and `cache` properties to use Foundation `NSURLCache` system.
+ 
+ WebDAV system supported by many cloud services including [Box.com](https://www.box.com/home) 
+ and [Yandex disk](https://disk.yandex.com) and [ownCloud](https://owncloud.org).
+ 
+ - Important: Because this class uses `URLSession`, it's necessary to disable App Transport Security
+     in case of using this class with unencrypted HTTP connection.
+     [Read this to know how](http://iosdevtips.co/post/121756573323/ios-9-xcode-7-http-connect-server-error).
+*/
+open class WebDAVFileProvider: HTTPFileProvider {
+    override open class var type: String { return "WebDAV" }
+    public var credentialType: HTTPAuthenticationType = .digest
    
-    // codebeat:disable[ARITY]
-    public init(absoluteURL: URL, name: String, path: String, size: Int64 = -1, contentType: String = "", createdDate: Date? = nil, modifiedDate: Date? = nil, fileType: FileType = .regular, isHidden: Bool = false, isReadOnly: Bool = false, entryTag: String? = nil) {
-        self.contentType = contentType
-        self.entryTag = entryTag
-        super.init(absoluteURL: absoluteURL, name: name, path: path, size: size, createdDate: createdDate, modifiedDate: modifiedDate, fileType: fileType, isHidden: isHidden, isReadOnly: isReadOnly)
-    }
-    // codebeat:enable[ARITY]
-}
-
-// Because this class uses NSURLSession, it's necessary to disable App Transport Security
-// in case of using this class with unencrypted HTTP connection.
-
-open class WebDAVFileProvider: NSObject,  FileProviderBasic {
-    open static let type: String = "WebDAV"
-    open let isPathRelative: Bool = true
-    open let baseURL: URL?
-    open var currentPath: String = ""
-    open var dispatch_queue: DispatchQueue {
-        willSet {
-            assert(_session == nil, "It's not effective to change dispatch_queue property after session is initialized.")
-        }
-    }
-    open weak var delegate: FileProviderDelegate?
-    open let credential: URLCredential?
-    
-    fileprivate var _session: URLSession?
-    fileprivate var sessionDelegate: SessionDelegate?
-    fileprivate var session: URLSession {
-        if _session == nil {
-            self.sessionDelegate = SessionDelegate(fileProvider: self, credential: credential)
-            let queue = OperationQueue()
-            //queue.underlyingQueue = dispatch_queue
-            _session = URLSession(configuration: URLSessionConfiguration.default, delegate: sessionDelegate as URLSessionDownloadDelegate?, delegateQueue: queue)
-        }
-        return _session!
-    }
-    
-    public init? (baseURL: URL, credential: URLCredential?) {
+    /**
+     Initializes WebDAV provider.
+     
+     - Parameters:
+       - baseURL: Location of WebDAV server.
+       - credential: An `URLCredential` object with `user` and `password`.
+       - cache: A URLCache to cache downloaded files and contents.
+    */
+    public init? (baseURL: URL, credential: URLCredential?, cache: URLCache? = nil) {
        if  !["http", "https"].contains(baseURL.uw_scheme.lowercased()) {
            return nil
        }
-        self.baseURL = baseURL
-        dispatch_queue = DispatchQueue(label: "FileProvider.\(WebDAVFileProvider.type)", attributes: DispatchQueue.Attributes.concurrent)
-        //let url = baseURL.uw_absoluteString
-        self.credential = credential
+        let refinedBaseURL = (baseURL.absoluteString.hasSuffix("/") ? baseURL : baseURL.appendingPathComponent("")).absoluteURL
+        super.init(baseURL: refinedBaseURL, credential: credential, cache: cache)
    }
    
-    deinit {
-        _session?.invalidateAndCancel()
+    public required convenience init?(coder aDecoder: NSCoder) {
+        guard let baseURL = aDecoder.decodeObject(forKey: "baseURL") as? URL else {
+            return nil
+        }
+        self.init(baseURL: baseURL,
+                  credential: aDecoder.decodeObject(forKey: "credential") as? URLCredential)
+        self.currentPath   = aDecoder.decodeObject(forKey: "currentPath") as? String ?? ""
+        self.useCache        = aDecoder.decodeBool(forKey: "useCache")
+        self.validatingCache = aDecoder.decodeBool(forKey: "validatingCache")
    }
    
-    open func contentsOfDirectory(path: String, completionHandler: @escaping ((_ contents: [FileObject], _ error: Error?) -> Void)) {
-        let url = absoluteURL(path)
+    override open func copy(with zone: NSZone? = nil) -> Any {
+        let copy = WebDAVFileProvider(baseURL: self.baseURL!, credential: self.credential, cache: self.cache)!
+        copy.currentPath = self.currentPath
+        copy.delegate = self.delegate
+        copy.fileOperationDelegate = self.fileOperationDelegate
+        copy.useCache = self.useCache
+        copy.validatingCache = self.validatingCache
+        return copy
+    }
+    
+    override open func contentsOfDirectory(path: String, completionHandler: @escaping (([FileObject], Error?) -> Void)) {
+        self.contentsOfDirectory(path: path, including: [], completionHandler: completionHandler)
+    }
+    
+    /**
+     Returns an Array of `FileObject`s identifying the the directory entries via asynchronous completion handler.
+     
+     If the directory contains no entries or an error is occured, this method will return the empty array.
+     
+     - Parameter path: path to target directory. If empty, `currentPath` value will be used.
+     - Parameter including: An array which determines which file properties should be considered to fetch.
+     - Parameter completionHandler: a closure with result of directory entries or error.
+         - `contents`: An array of `FileObject` identifying the the directory entries.
+         - `error`: Error returned by system.
+     */
+    open func contentsOfDirectory(path: String, including: [URLResourceKey], completionHandler: @escaping ((_ contents: [FileObject], _ error: Error?) -> Void)) {
+        let opType = FileOperationType.fetch(path: path)
+        let url = self.url(of: path).appendingPathComponent("")
        var request = URLRequest(url: url)
        request.httpMethod = "PROPFIND"
        request.setValue("1", forHTTPHeaderField: "Depth")
-        request.setValue("text/xml; charset=\"utf-8\"", forHTTPHeaderField: "Content-Type")
-        request.httpBody = "<?xml version=\"1.0\" encoding=\"utf-8\" ?>\n<D:propfind xmlns:D=\"DAV:\">\n<D:allprop/></D:propfind>".data(using: .utf8)
+        request.set(httpAuthentication: credential, with: credentialType)
+        request.set(contentType: .xml)
+        request.httpBody = "<?xml version=\"1.0\" encoding=\"utf-8\" ?>\n<D:propfind xmlns:D=\"DAV:\">\n\(WebDavFileObject.propString(including))\n</D:propfind>".data(using: .utf8)
        request.setValue(String(request.httpBody!.count), forHTTPHeaderField: "Content-Length")
-        let task = session.dataTask(with: request, completionHandler: { (data, response, error) in
+        runDataTask(with: request, operation: opType, completionHandler: { (data, response, error) in
            var responseError: FileProviderWebDavError?
            if let code = (response as? HTTPURLResponse)?.statusCode , code >= 300, let rCode = FileProviderHTTPErrorCode(rawValue: code) {
-                responseError = FileProviderWebDavError(code: rCode, url: url)
+                responseError = FileProviderWebDavError(code: rCode, path: path, errorDescription: String(data: data ?? Data(), encoding: .utf8), url: url)
            }
+            var fileObjects = [WebDavFileObject]()
            if let data = data {
-                let xresponse = self.parseXMLResponse(data)
-                var fileObjects = [WebDavFileObject]()
-                for attr in xresponse {
+                let xresponse = DavResponse.parse(xmlResponse: data, baseURL: self.baseURL)
+                for attr in xresponse where attr.href != url {
                    if attr.href.path == url.path {
                        continue
                    }
-                    fileObjects.append(self.mapToFileObject(attr))
+                    fileObjects.append(WebDavFileObject(attr))
                }
-                completionHandler(fileObjects, responseError ?? error)
-                return
            }
-            completionHandler([], responseError ?? error)
-        }) 
-        task.resume()
+            completionHandler(fileObjects, responseError ?? error)
+        })
    }
    
-    open func attributesOfItem(path: String, completionHandler: @escaping ((_ attributes: FileObject?, _ error: Error?) -> Void)) {
-        let url = absoluteURL(path)
+    override open func attributesOfItem(path: String, completionHandler: @escaping ((_ attributes: FileObject?, _ error: Error?) -> Void)) {
+        self.attributesOfItem(path: path, including: [], completionHandler: completionHandler)
+    }
+    
+    /**
+     Returns a `FileObject` containing the attributes of the item (file, directory, symlink, etc.) at the path in question via asynchronous completion handler.
+     
+     If the directory contains no entries or an error is occured, this method will return the empty `FileObject`.
+     
+     - Parameter path: path to target directory. If empty, `currentPath` value will be used.
+     - Parameter including: An array which determines which file properties should be considered to fetch.
+     - Parameter completionHandler: a closure with result of directory entries or error.
+         - `attributes`: A `FileObject` containing the attributes of the item.
+         - `error`: Error returned by system.
+     */
+    open func attributesOfItem(path: String, including: [URLResourceKey], completionHandler: @escaping ((_ attributes: FileObject?, _ error: Error?) -> Void)) {
+        let url = self.url(of: path)
        var request = URLRequest(url: url)
        request.httpMethod = "PROPFIND"
        request.setValue("1", forHTTPHeaderField: "Depth")
-        request.setValue("text/xml; charset=\"utf-8\"", forHTTPHeaderField: "Content-Type")
-        request.httpBody = "<?xml version=\"1.0\" encoding=\"utf-8\" ?>\n<D:propfind xmlns:D=\"DAV:\">\n<D:allprop/></D:propfind>".data(using: .utf8)
+        request.set(httpAuthentication: credential, with: credentialType)
+        request.set(contentType: .xml)
+        request.httpBody = "<?xml version=\"1.0\" encoding=\"utf-8\" ?>\n<D:propfind xmlns:D=\"DAV:\">\n\(WebDavFileObject.propString(including))\n</D:propfind>".data(using: .utf8)
        request.setValue(String(request.httpBody!.count), forHTTPHeaderField: "Content-Length")
-        let task = session.dataTask(with: request, completionHandler: { (data, response, error) in
+        runDataTask(with: request, completionHandler: { (data, response, error) in
            var responseError: FileProviderWebDavError?
            if let code = (response as? HTTPURLResponse)?.statusCode, code >= 300, let rCode = FileProviderHTTPErrorCode(rawValue: code) {
-                responseError = FileProviderWebDavError(code: rCode, url: url)
+                responseError = FileProviderWebDavError(code: rCode, path: path, errorDescription: String(data: data ?? Data(), encoding: .utf8), url: url)
            }
            if let data = data {
-                let xresponse = self.parseXMLResponse(data)
+                let xresponse = DavResponse.parse(xmlResponse: data, baseURL: self.baseURL)
                if let attr = xresponse.first {
-                    completionHandler(self.mapToFileObject(attr), responseError ?? error)
+                    completionHandler(WebDavFileObject(attr), responseError ?? error)
                    return
                }
            }
            completionHandler(nil, responseError ?? error)
        })
-        task.resume()
    }
    
-    open func storageProperties(completionHandler: @escaping ((_ total: Int64, _ used: Int64) -> Void)) {
+    override open func storageProperties(completionHandler: @escaping ((_ total: Int64, _ used: Int64) -> Void)) {
        // Not all WebDAV clients implements RFC2518 which allows geting storage quota.
        // In this case you won't get error. totalSize is NSURLSessionTransferSizeUnknown
        // and used space is zero.
@@ -128,292 +155,148 @@ open class WebDAVFileProvider: NSObject,  FileProviderBasic {
        var request = URLRequest(url: baseURL)
        request.httpMethod = "PROPFIND"
        request.setValue("0", forHTTPHeaderField: "Depth")
-        request.setValue("text/xml; charset=\"utf-8\"", forHTTPHeaderField: "Content-Type")
+        request.set(httpAuthentication: credential, with: credentialType)
+        request.set(contentType: .xml)
        request.httpBody = "<?xml version=\"1.0\" encoding=\"utf-8\" ?>\n<D:propfind xmlns:D=\"DAV:\">\n<D:prop><D:quota-available-bytes/><D:quota-used-bytes/></D:prop>\n</D:propfind>".data(using: .utf8)
        request.setValue(String(request.httpBody!.count), forHTTPHeaderField: "Content-Length")
-        let task = session.dataTask(with: request, completionHandler: { (data, response, error) in
+        runDataTask(with: request, completionHandler: { (data, response, error) in
+            var totalSize: Int64 = -1
+            var usedSize: Int64 = 0
            if let data = data {
-                let xresponse = self.parseXMLResponse(data)
+                let xresponse = DavResponse.parse(xmlResponse: data, baseURL: self.baseURL)
                if let attr = xresponse.first {
-                    let totalSize = Int64(attr.prop["quota-available-bytes"] ?? "")
-                    let usedSize = Int64(attr.prop["quota-used-bytes"] ?? "")
-                    completionHandler(totalSize ?? -1, usedSize ?? 0)
-                    return
+                    totalSize = Int64(attr.prop["quota-available-bytes"] ?? "") ?? -1
+                    usedSize = Int64(attr.prop["quota-used-bytes"] ?? "") ?? 0
                }
            }
-            completionHandler(-1, 0)
-        }) 
-        task.resume()
+            completionHandler(totalSize, usedSize)
+        })
    }
    
-    open weak var fileOperationDelegate: FileOperationDelegate?
-}
-
-extension WebDAVFileProvider: FileProviderOperations {
-    @discardableResult
-    public func create(folder folderName: String, at atPath: String, completionHandler: SimpleCompletionHandler) -> OperationHandle? {
-        guard fileOperationDelegate?.fileProvider(self, shouldDoOperation: .create(path: (atPath as NSString).appendingPathComponent(folderName) + "/")) ?? true == true else {
-            return nil
-        }
-        let url = absoluteURL((atPath as NSString).appendingPathComponent(folderName) + "/")
-        var request = URLRequest(url: url)
-        request.httpMethod = "MKCOL"
-        let task = session.dataTask(with: request, completionHandler: { (data, response, error) in
-            var responseError: FileProviderWebDavError?
-            if let code = (response as? HTTPURLResponse)?.statusCode , code >= 300, let rCode = FileProviderHTTPErrorCode(rawValue: code) {
-                responseError = FileProviderWebDavError(code: rCode, url: url)
-            }
-            if let response = response as? HTTPURLResponse, let code = FileProviderHTTPErrorCode(rawValue: response.statusCode) , code != .ok {
-                completionHandler?(FileProviderWebDavError(code: code, url: url))
-                return
-            }
-            completionHandler?(responseError ?? error)
-            self.delegateNotify(.create(path: (atPath as NSString).appendingPathComponent(folderName) + "/"), error: responseError ?? error)
-        }) 
-        task.resume()
-        return RemoteOperationHandle(tasks: [task])
-    }
-    
-    @discardableResult
-    public func create(file fileAttribs: FileObject, at path: String, contents data: Data?, completionHandler: SimpleCompletionHandler) -> OperationHandle? {
-        guard fileOperationDelegate?.fileProvider(self, shouldDoOperation: .create(path: path)) ?? true == true else {
-            return nil
-        }
-        let url = absoluteURL(path)
-        var request = URLRequest(url: url)
-        request.httpMethod = "PUT"
-        let task = session.uploadTask(with: request, from: data, completionHandler: { (data, response, error) in
-            var responseError: FileProviderWebDavError?
-            if let code = (response as? HTTPURLResponse)?.statusCode , code >= 300, let rCode = FileProviderHTTPErrorCode(rawValue: code) {
-                responseError = FileProviderWebDavError(code: rCode, url: url)
-            }
-            completionHandler?(responseError ?? error)
-            self.delegateNotify(.create(path: (path as NSString).appendingPathComponent(fileAttribs.name)), error: responseError ?? error)
-        }) 
-        task.taskDescription = dictionaryToJSON(["type": "Create" as NSString, "source": (path as NSString).appendingPathComponent(fileAttribs.name) as NSString])
-        task.resume()
-        return RemoteOperationHandle(tasks: [task])
-    }
-    
-    @discardableResult
-    public func moveItem(path: String, to toPath: String, overwrite: Bool = false, completionHandler: SimpleCompletionHandler) -> OperationHandle? {
-        guard fileOperationDelegate?.fileProvider(self, shouldDoOperation: .move(source: path, destination: toPath)) ?? true == true else {
-            return nil
-        }
-        return self.copyMoveItem(move: true, path: path, toPath: toPath, overwrite: overwrite, completionHandler: completionHandler)
-    }
-    
-    @discardableResult
-    public func copyItem(path: String, to toPath: String, overwrite: Bool = false, completionHandler: SimpleCompletionHandler) -> OperationHandle? {
-        guard fileOperationDelegate?.fileProvider(self, shouldDoOperation: .copy(source: path, destination: toPath)) ?? true == true else {
-            return nil
-        }
-        return self.copyMoveItem(move: false, path: path, toPath: toPath, overwrite: overwrite, completionHandler: completionHandler)
-    }
-    
-    fileprivate func copyMoveItem(move:Bool, path: String, toPath: String, overwrite: Bool, completionHandler: SimpleCompletionHandler) -> OperationHandle? {
-        let url = absoluteURL(path)
-        var request = URLRequest(url: url)
-        if move {
-            request.httpMethod = "MOVE"
-        } else {
-            request.httpMethod = "COPY"
-        }
-        request.setValue(absoluteURL(path).absoluteString, forHTTPHeaderField: "Destination")
-        if !overwrite {
-            request.setValue("F", forHTTPHeaderField: "Overwrite")
-        }
-        let task = session.dataTask(with: request, completionHandler: { (data, response, error) in
-            if let response = response as? HTTPURLResponse, let code = FileProviderHTTPErrorCode(rawValue: response.statusCode) {
-                defer {
-                    let op = move ? FileOperationType.move(source: path, destination: toPath) : .copy(source: path, destination: toPath)
-                    self.delegateNotify(op, error: error)
-                }
-                if code == .multiStatus, let data = data {
-                    let xresponses = self.parseXMLResponse(data)
-                    for xresponse in xresponses where (xresponse.status ?? 0) >= 300 {
-                        completionHandler?(FileProviderWebDavError(code: code, url: url))
-                    }
-                } else {
-                    completionHandler?(FileProviderWebDavError(code: code, url: url))
-                }
-                return
-            }
-            completionHandler?(error)
-        }) 
-        task.resume()
-        return RemoteOperationHandle(tasks: [task])
-    }
-    
-    @discardableResult
-    public func removeItem(path: String, completionHandler: SimpleCompletionHandler) -> OperationHandle? {
-        guard fileOperationDelegate?.fileProvider(self, shouldDoOperation: .remove(path: path)) ?? true == true else {
-            return nil
-        }
-        let url = absoluteURL(path)
-        var request = URLRequest(url: url)
-        request.httpMethod = "DELETE"
-        let task = session.dataTask(with: request, completionHandler: { (data, response, error) in
-            if let response = response as? HTTPURLResponse, let code = FileProviderHTTPErrorCode(rawValue: response.statusCode) {
-                defer {
-                    self.delegateNotify(.remove(path: path), error: error)
-                }
-                if code == .multiStatus, let data = data {
-                    let xresponses = self.parseXMLResponse(data)
-                    for xresponse in xresponses where (xresponse.status ?? 0) >= 300 {
-                        completionHandler?(FileProviderWebDavError(code: code, url: url))
-                    }
-                } else {
-                    completionHandler?(FileProviderWebDavError(code: code, url: url))
-                }
-                return
-            }
-            completionHandler?(error)
-        }) 
-        task.resume()
-        return RemoteOperationHandle(tasks: [task])
-    }
-    
-    @discardableResult
-    public func copyItem(localFile: URL, to toPath: String, completionHandler: SimpleCompletionHandler) -> OperationHandle? {
-        guard fileOperationDelegate?.fileProvider(self, shouldDoOperation: .copy(source: localFile.absoluteString, destination: toPath)) ?? true == true else {
-            return nil
-        }
-        let url = absoluteURL(toPath)
-        var request = URLRequest(url: url)
-        request.httpMethod = "PUT"
-        let task = session.uploadTask(with: request, fromFile: localFile, completionHandler: { (data, response, error) in
-            var responseError: FileProviderWebDavError?
-            if let code = (response as? HTTPURLResponse)?.statusCode , code >= 300, let rCode = FileProviderHTTPErrorCode(rawValue: code) {
-                responseError = FileProviderWebDavError(code: rCode, url: url)
-            }
-            completionHandler?(responseError ?? error)
-            self.delegateNotify(.move(source: localFile.absoluteString, destination: toPath), error: responseError ?? error)
-        }) 
-        task.taskDescription = dictionaryToJSON(["type": "Copy" as NSString, "source": localFile.absoluteString as NSString, "dest": toPath as NSString])
-        task.resume()
-        return RemoteOperationHandle(tasks: [task])
-    }
-    
-    @discardableResult
-    public func copyItem(path: String, toLocalURL: URL, completionHandler: SimpleCompletionHandler) -> OperationHandle? {
-        guard fileOperationDelegate?.fileProvider(self, shouldDoOperation: .copy(source: path, destination: toLocalURL.absoluteString)) ?? true == true else {
-            return nil
-        }
-        let url = absoluteURL(path)
-        let request = URLRequest(url: url)
-        let task = session.downloadTask(with: request, completionHandler: { (sourceFileURL, response, error) in
-            var responseError: FileProviderWebDavError?
-            if let code = (response as? HTTPURLResponse)?.statusCode , code >= 300, let rCode = FileProviderHTTPErrorCode(rawValue: code) {
-                responseError = FileProviderWebDavError(code: rCode, url: url)
-            }
-            if let sourceFileURL = sourceFileURL {
-                do {
-                    try FileManager.default.copyItem(at: sourceFileURL, to: toLocalURL)
-                } catch let e {
-                    completionHandler?(e)
-                    return
-                }
-            }
-            completionHandler?(responseError ?? error)
-        }) 
-        task.taskDescription = dictionaryToJSON(["type": "Copy" as NSString, "source": path as NSString, "dest": toLocalURL.absoluteString as NSString])
-        task.resume()
-        return RemoteOperationHandle(tasks: [task])
-    }
-}
-
-extension WebDAVFileProvider: FileProviderReadWrite {
-    @discardableResult
-    public func contents(path: String, completionHandler: @escaping ((_ contents: Data?, _ error: Error?) -> Void)) -> OperationHandle? {
-        return self.contents(path: path, offset: 0, length: -1, completionHandler: completionHandler)
-    }
-    
-    @discardableResult
-    public func contents(path: String, offset: Int64, length: Int, completionHandler: @escaping ((_ contents: Data?, _ error: Error?) -> Void)) -> OperationHandle? {
-        let url = absoluteURL(path)
-        var request = URLRequest(url: url)
-        request.httpMethod = "GET"
-        if length > 0 {
-            request.setValue("bytes=\(offset)-\(offset + length)", forHTTPHeaderField: "Range")
-        } else if offset > 0 && length < 0 {
-            request.setValue("bytes=\(offset)-", forHTTPHeaderField: "Range")
-        }
-        let task = session.dataTask(with: request, completionHandler: { (data, response, error) in
-            var responseError: FileProviderWebDavError?
-            if let code = (response as? HTTPURLResponse)?.statusCode , code >= 300, let rCode = FileProviderHTTPErrorCode(rawValue: code) {
-                responseError = FileProviderWebDavError(code: rCode, url: url)
-            }
-            completionHandler(data, responseError ?? error)
-        }) 
-        task.resume()
-        return RemoteOperationHandle(tasks: [task])
-    }
-    
-    @discardableResult
-    public func writeContents(path: String, contents data: Data, atomically: Bool = false, completionHandler: SimpleCompletionHandler) -> OperationHandle? {
-        guard fileOperationDelegate?.fileProvider(self, shouldDoOperation: .modify(path: path)) ?? true == true else {
-            return nil
-        }
-        // FIXME: lock destination before writing process
-        let url = atomically ? absoluteURL(path).appendingPathExtension("tmp") : absoluteURL(path)
-        var request = URLRequest(url: url)
-        request.httpMethod = "PUT"
-        let task = session.uploadTask(with: request, from: data, completionHandler: { (data, response, error) in
-            var responseError: FileProviderWebDavError?
-            if let code = (response as? HTTPURLResponse)?.statusCode , code >= 300, let rCode = FileProviderHTTPErrorCode(rawValue: code) {
-                responseError = FileProviderWebDavError(code: rCode, url: self.absoluteURL(path))
-            }
-            defer {
-                self.delegateNotify(.modify(path: path), error: responseError ?? error)
-            }
-            if let error = error {
-                completionHandler?(error)
-                return
-            }
-            if atomically {
-                self.moveItem(path: (path as NSString).appendingPathExtension("tmp")!, to: path, completionHandler: completionHandler)
-            }
-        }) 
-        task.taskDescription = dictionaryToJSON(["type": "Modify" as NSString, "source": path as NSString])
-        task.resume()
-        return RemoteOperationHandle(tasks: [task])
-    }
-    
-    public func searchFiles(path: String, recursive: Bool, query: String, foundItemHandler: ((FileObject) -> Void)?, completionHandler: @escaping ((_ files: [FileObject], _ error: Error?) -> Void)) {
-        let url = absoluteURL(path)
+    override open func searchFiles(path: String, recursive: Bool, query: NSPredicate, foundItemHandler: ((FileObject) -> Void)?, completionHandler: @escaping ((_ files: [FileObject], _ error: Error?) -> Void)) -> Progress? {
+        let url = self.url(of: path)
        var request = URLRequest(url: url)
        request.httpMethod = "PROPFIND"
        //request.setValue("1", forHTTPHeaderField: "Depth")
-        request.setValue("text/xml; charset=\"utf-8\"", forHTTPHeaderField: "Content-Type")
+        request.set(httpAuthentication: credential, with: credentialType)
+        request.set(contentType: .xml)
        request.httpBody = "<?xml version=\"1.0\" encoding=\"utf-8\" ?>\n<D:propfind xmlns:D=\"DAV:\">\n<D:allprop/></D:propfind>".data(using: .utf8)
-        request.setValue(String(request.httpBody!.count), forHTTPHeaderField: "Content-Length")
-        let task = session.dataTask(with: request, completionHandler: { (data, response, error) in
+        let progress = Progress(parent: nil, userInfo: nil)
+        progress.setUserInfoObject(url, forKey: .fileURLKey)
+        let task = session.dataTask(with: request) { (data, response, error) in
            // FIXME: paginating results
            var responseError: FileProviderWebDavError?
            if let code = (response as? HTTPURLResponse)?.statusCode , code >= 300, let rCode = FileProviderHTTPErrorCode(rawValue: code) {
-                responseError = FileProviderWebDavError(code: rCode, url: url)
+                responseError = FileProviderWebDavError(code: rCode, path: path, errorDescription: String(data: data ?? Data(), encoding: .utf8), url: url)
            }
            if let data = data {
-                let xresponse = self.parseXMLResponse(data)
+                let xresponse = DavResponse.parse(xmlResponse: data, baseURL: self.baseURL)
                var fileObjects = [WebDavFileObject]()
                for attr in xresponse {
-                    let path = attr.href.path
-                    if !((path as NSString).lastPathComponent.contains(query)) {
+                    let fileObject = WebDavFileObject(attr)
+                    if !query.evaluate(with: fileObject.mapPredicate()) {
                        continue
                    }
-                    let fileObject = self.mapToFileObject(attr)
+                    
                    fileObjects.append(fileObject)
+                    progress.completedUnitCount = Int64(fileObjects.count)
                    foundItemHandler?(fileObject)
                }
                completionHandler(fileObjects, responseError ?? error)
                return
            }
            completionHandler([], responseError ?? error)
-        }) 
+        }
+        progress.cancellationHandler = { [weak task] in
+            task?.cancel()
+        }
+        progress.setUserInfoObject(Date(), forKey: .startingTimeKey)
        task.resume()
+        return progress
    }
    
+    override open func isReachable(completionHandler: @escaping (Bool) -> Void) {
+        var request = URLRequest(url: baseURL!)
+        request.httpMethod = "PROPFIND"
+        request.setValue("0", forHTTPHeaderField: "Depth")
+        request.set(httpAuthentication: credential, with: credentialType)
+        request.set(contentType: .xml)
+        request.httpBody = "<?xml version=\"1.0\" encoding=\"utf-8\" ?>\n<D:propfind xmlns:D=\"DAV:\">\n<D:prop><D:quota-available-bytes/><D:quota-used-bytes/></D:prop>\n</D:propfind>".data(using: .utf8)
+        request.setValue(String(request.httpBody!.count), forHTTPHeaderField: "Content-Length")
+        runDataTask(with: request, completionHandler: { (data, response, error) in
+            let status = (response as? HTTPURLResponse)?.statusCode ?? 400
+            completionHandler(status < 300)
+        })
+    }
+    
+    override func request(for operation: FileOperationType, overwrite: Bool = true, attributes: [URLResourceKey: Any] = [:]) -> URLRequest {
+        let method: String
+        let url: URL
+        let sourceURL = self.url(of: operation.source)
+        
+        switch operation {
+        case .fetch:
+            method = "GET"
+            url = sourceURL
+        case .create:
+            if sourceURL.absoluteString.hasSuffix("/") {
+                method = "MKCOL"
+                url = sourceURL
+            } else {
+                fallthrough
+            }
+        case .modify:
+            method = "PUT"
+            url = sourceURL
+            break
+        case .copy(let source, let dest):
+            if source.hasPrefix("file://") {
+                method = "PUT"
+                url = self.url(of: dest)
+            } else if dest.hasPrefix("file://") {
+                method = "GET"
+                url = sourceURL
+            } else {
+                method = "COPY"
+                url = sourceURL
+            }
+        case .move:
+            method = "MOVE"
+            url = sourceURL
+        case .remove:
+            method = "DELETE"
+            url = sourceURL
+        default:
+            fatalError("Unimplemented operation \(operation.description) in \(#file)")
+        }
+        
+        var request = URLRequest(url: url)
+        request.httpMethod = method
+        request.set(httpAuthentication: credential, with: credentialType)
+        request.setValue(overwrite ? "T" : "F", forHTTPHeaderField: "Overwrite")
+        if let dest = operation.destination, !dest.hasPrefix("file://") {
+            request.setValue(self.url(of:dest).absoluteString, forHTTPHeaderField: "Destination")
+        }
+        
+        return request
+    }
+    
+    override func serverError(with code: FileProviderHTTPErrorCode, path: String?, data: Data?) -> FileProviderHTTPError {
+        return FileProviderWebDavError(code: code, path: path ?? "", errorDescription:  data.flatMap({ String(data: $0, encoding: .utf8) }), url: self.url(of: path))
+    }
+    
+    override func multiStatusHandler(source: String, data: Data, completionHandler: SimpleCompletionHandler) {
+        let xresponses = DavResponse.parse(xmlResponse: data, baseURL: self.baseURL)
+        for xresponse in xresponses where (xresponse.status ?? 0) >= 300 {
+            let code = xresponse.status.flatMap { FileProviderHTTPErrorCode(rawValue: $0) } ?? .internalServerError
+            let error = FileProviderWebDavError(code: code, path: source, errorDescription: String(data: data, encoding: .utf8), url: self.url(of: source))
+            completionHandler?(error)
+        }
+    }
+}
+extension WebDAVFileProvider {
+    
+    /*
    fileprivate func registerNotifcation(path: String, eventHandler: (() -> Void)) {
        /* There is no unified api for monitoring WebDAV server content change/update
         * Microsoft Exchange uses SUBSCRIBE method, Apple uses push notification system.
@@ -421,49 +304,110 @@ extension WebDAVFileProvider: FileProviderReadWrite {
         * A messy approach is listing a directory with an interval period and compare
         * with previous results
         */
+        NotImplemented()
    }
    fileprivate func unregisterNotifcation(path: String) {
-        
-    }
+        NotImplemented()
+    }*/
    // TODO: implements methods for lock mechanism
 }

-extension WebDAVFileProvider: FileProvider {}
+extension WebDAVFileProvider: ExtendedFileProvider {
+    open func thumbnailOfFileSupported(path: String) -> Bool {
+        guard self.baseURL?.host?.contains("dav.yandex.") ?? false else {
+            return false
+        }
+        let supportedExt: [String] = ["jpg", "jpeg", "png", "gif"]
+        return supportedExt.contains((path as NSString).pathExtension)
+    }
+    
+    open func thumbnailOfFile(path: String, dimension: CGSize?, completionHandler: @escaping ((ImageClass?, Error?) -> Void)) {
+        guard self.baseURL?.host?.contains("dav.yandex.") ?? false else {
+            dispatch_queue.async {
+                completionHandler(nil, self.throwError(path, code: URLError.resourceUnavailable))
+            }
+            return
+        }
+        
+        let dimension = dimension ?? CGSize(width: 64, height: 64)
+        let url = URL(string: self.url(of: path).absoluteString + "?preview&size=\(dimension.width)x\(dimension.height)")!
+        var request = URLRequest(url: url)
+        request.httpMethod = "GET"
+        request.set(httpAuthentication: credential, with: credentialType)
+        let task = session.dataTask(with: request, completionHandler: { (data, response, error) in
+            var responseError: FileProviderWebDavError?
+            if let code = (response as? HTTPURLResponse)?.statusCode , code >= 300, let rCode = FileProviderHTTPErrorCode(rawValue: code) {
+                responseError = FileProviderWebDavError(code: rCode, path: url.relativePath, errorDescription: String(data: data ?? Data(), encoding: .utf8), url: url)
+                completionHandler(nil, responseError ?? error)
+                return
+            }
+            
+            completionHandler(data.flatMap({ ImageClass(data: $0) }), nil)
+        })
+        task.resume()
+    }
+    
+    open func propertiesOfFileSupported(path: String) -> Bool {
+        return false
+    }
+    
+    open func propertiesOfFile(path: String, completionHandler: @escaping (([String : Any], [String], Error?) -> Void)) {
+        dispatch_queue.async {
+            completionHandler([:], [], self.throwError(path, code: URLError.resourceUnavailable))
+        }
+    }
+}
+
+extension WebDAVFileProvider: FileProviderSharing {
+    open func publicLink(to path: String, completionHandler: @escaping ((URL?, FileObject?, Date?, Error?) -> Void)) {
+        guard self.baseURL?.host?.contains("dav.yandex.") ?? false else {
+            dispatch_queue.async {
+                completionHandler(nil, nil, nil, self.throwError(path, code: URLError.resourceUnavailable))
+            }
+            return
+        }
+        
+        let url = self.url(of: path)
+        var request = URLRequest(url: url)
+        request.httpMethod = "PROPPATCH"
+        request.set(httpAuthentication: credential, with: credentialType)
+        request.set(contentType: .xml)
+        let body = "<propertyupdate xmlns=\"DAV:\">\n<set><prop>\n<public_url xmlns=\"urn:yandex:disk:meta\">true</public_url>\n</prop></set>\n</propertyupdate>"
+        request.httpBody = body.data(using: .utf8)
+        request.setValue(String(request.httpBody!.count), forHTTPHeaderField: "Content-Length")
+        runDataTask(with: request, completionHandler: { (data, response, error) in
+            var responseError: FileProviderWebDavError?
+            if let code = (response as? HTTPURLResponse)?.statusCode, code >= 300, let rCode = FileProviderHTTPErrorCode(rawValue: code) {
+                responseError = FileProviderWebDavError(code: rCode, path: path, errorDescription: String(data: data ?? Data(), encoding: .utf8), url: url)
+            }
+            if let data = data {
+                let xresponse = DavResponse.parse(xmlResponse: data, baseURL: self.baseURL)
+                if let urlStr = xresponse.first?.prop["public_url"], let url = URL(string: urlStr) {
+                    completionHandler(url, nil, nil, nil)
+                    return
+                }
+            }
+            completionHandler(nil, nil, nil, responseError ?? error)
+        })
+    }
+}

 // MARK: WEBDAV XML response implementation

-internal extension WebDAVFileProvider {
-    struct DavResponse {
-        let href: URL
-        let hrefString: String
-        let status: Int?
-        let prop: [String: String]
-    }
+struct DavResponse {
+    let href: URL
+    let hrefString: String
+    let status: Int?
+    let prop: [String: String]
    
-    fileprivate func parseXMLResponse(_ response: Data) -> [DavResponse] {
-        var result = [DavResponse]()
-        do {
-            let xml = try AEXMLDocument(xml: response)
-            var rootnode = xml.root
-            var responsetag = "response"
-            for node in rootnode.all ?? [] where node.name.lowercased().hasSuffix("multistatus") {
-                rootnode = node
-            }
-            for node in rootnode.children where node.name.lowercased().hasSuffix("response") {
-                responsetag = node.name
-                break
-            }
-            for responseNode in rootnode[responsetag].all ?? [] {
-                if let davResponse = mapNodeToDavResponse(responseNode) {
-                    result.append(davResponse)
-                }
-            }
-        } catch _ { 
+    init? (_ node: AEXMLElement, baseURL: URL?) {
+        
+        func standardizePath(_ str: String) -> String {
+            let trimmedStr = str.hasPrefix("/") ? str.substring(from: str.index(after: str.startIndex)) : str
+            return trimmedStr.addingPercentEncoding(withAllowedCharacters: CharacterSet.urlPathAllowed.subtracting(CharacterSet(charactersIn: ":"))) ?? str
        }
-        return result
-    }
-    
-    fileprivate func mapNodeToDavResponse(_ node: AEXMLElement) -> DavResponse? {
+        
+        // find node names with namespace
        var hreftag = "href"
        var statustag = "status"
        var propstattag = "propstat"
@@ -478,70 +422,150 @@ internal extension WebDAVFileProvider {
                propstattag = node.name
            }
        }
-        let href = node[hreftag].value
-        if let href = href, let hrefURL = URL(string: href) {
-            var status: Int?
-            let statusDesc = (node[statustag].string).components(separatedBy: " ")
-            if statusDesc.count > 2 {
-                status = Int(statusDesc[1])
-            }
-            var propDic = [String: String]()
-            let propStatNode = node[propstattag]
-            for node in propStatNode.children where node.name.lowercased().hasSuffix("status"){
-                statustag = node.name
-                break
-            }
-            let statusDesc2 = (propStatNode[statustag].string).components(separatedBy: " ")
-            if statusDesc2.count > 2 {
-                status = Int(statusDesc2[1])
-            }
-            var proptag = "prop"
-            for tnode in propStatNode.children where tnode.name.lowercased().hasSuffix("prop") {
-                proptag = tnode.name
-                break
-            }
-            for propItemNode in propStatNode[proptag].children {
-                propDic[propItemNode.name.components(separatedBy: ":").last!.lowercased()] = propItemNode.value
-                if propItemNode.name.hasSuffix("resourcetype") && propItemNode.xml.contains("collection") {
-                    propDic["getcontenttype"] = "httpd/unix-directory"
-                }
-            }
-            return DavResponse(href: hrefURL, hrefString: href, status: status, prop: propDic)
+        
+        guard let hrefString = node[hreftag].value else { return nil }
+        
+        // trying to figure out relative path out of href
+        let hrefAbsolute = URL(string: hrefString, relativeTo: baseURL)?.absoluteURL
+        let relativePath: String
+        if hrefAbsolute?.host?.replacingOccurrences(of: "www.", with: "", options: .anchored) == baseURL?.host?.replacingOccurrences(of: "www.", with: "", options: .anchored) {
+            relativePath = hrefAbsolute?.path.replacingOccurrences(of: baseURL?.absoluteURL.path ?? "", with: "", options: .anchored, range: nil) ?? hrefString
+        } else {
+            relativePath = hrefAbsolute?.absoluteString.replacingOccurrences(of: baseURL?.absoluteString ?? "", with: "", options: .anchored, range: nil) ?? hrefString
        }
-        return nil
+        let hrefURL = URL(string: standardizePath(relativePath), relativeTo: baseURL) ?? baseURL
+        
+        guard let href = hrefURL?.standardized else { return nil }
+        
+        // reading status and properties
+        var status: Int?
+        let statusDesc = (node[statustag].string).components(separatedBy: " ")
+        if statusDesc.count > 2 {
+            status = Int(statusDesc[1])
+        }
+        var propDic = [String: String]()
+        let propStatNode = node[propstattag]
+        for node in propStatNode.children where node.name.lowercased().hasSuffix("status"){
+            statustag = node.name
+            break
+        }
+        let statusDesc2 = (propStatNode[statustag].string).components(separatedBy: " ")
+        if statusDesc2.count > 2 {
+            status = Int(statusDesc2[1])
+        }
+        var proptag = "prop"
+        for tnode in propStatNode.children where tnode.name.lowercased().hasSuffix("prop") {
+            proptag = tnode.name
+            break
+        }
+        for propItemNode in propStatNode[proptag].children {
+            propDic[propItemNode.name.components(separatedBy: ":").last!.lowercased()] = propItemNode.value
+            if propItemNode.name.hasSuffix("resourcetype") && propItemNode.xml.contains("collection") {
+                propDic["getcontenttype"] = "httpd/unix-directory"
+            }
+        }
+        self.href = href
+        self.hrefString = hrefString
+        self.status = status
+        self.prop = propDic
    }
    
-    fileprivate func mapToFileObject(_ davResponse: DavResponse) -> WebDavFileObject {
-        var href = davResponse.href
-        if href.baseURL == nil {
-            href = absoluteURL(href.path)
+    static func parse(xmlResponse: Data, baseURL: URL?) -> [DavResponse] {
+        guard let xml = try? AEXMLDocument(xml: xmlResponse) else { return [] }
+        var result = [DavResponse]()
+        var rootnode = xml.root
+        var responsetag = "response"
+        for node in rootnode.all ?? [] where node.name.lowercased().hasSuffix("multistatus") {
+            rootnode = node
        }
-        let name = davResponse.prop["displayname"] ?? (davResponse.hrefString.removingPercentEncoding! as NSString).lastPathComponent
-        let size = Int64(davResponse.prop["getcontentlength"] ?? "-1") ?? NSURLSessionTransferSizeUnknown
-        let createdDate = self.resolve(dateString: davResponse.prop["creationdate"] ?? "")
-        let modifiedDate = self.resolve(dateString: davResponse.prop["getlastmodified"] ?? "")
-        let contentType = davResponse.prop["getcontenttype"] ?? "octet/stream"
-        let isDirectory = contentType == "httpd/unix-directory"
-        let entryTag = davResponse.prop["getetag"]
-        return WebDavFileObject(absoluteURL: href, name: name, path: href.path, size: size, contentType: contentType, createdDate: createdDate, modifiedDate: modifiedDate, fileType: isDirectory ? .directory : .regular, isHidden: false, isReadOnly: false, entryTag: entryTag)
-    }
-    
-    fileprivate func delegateNotify(_ operation: FileOperationType, error: Error?) {
-        DispatchQueue.main.async(execute: {
-            if error == nil {
-                self.delegate?.fileproviderSucceed(self, operation: operation)
-            } else {
-                self.delegate?.fileproviderFailed(self, operation: operation)
+        for node in rootnode.children where node.name.lowercased().hasSuffix("response") {
+            responsetag = node.name
+            break
+        }
+        for responseNode in rootnode[responsetag].all ?? [] {
+            if let davResponse = DavResponse(responseNode, baseURL: baseURL) {
+                result.append(davResponse)
            }
-        })
+        }
+        return result
    }
 }

-public struct FileProviderWebDavError: Error, CustomStringConvertible {
-    public let code: FileProviderHTTPErrorCode
-    public let url: URL
+/// Containts path, url and attributes of a WebDAV file or resource.
+public final class WebDavFileObject: FileObject {
+    internal init(_ davResponse: DavResponse) {
+        let href = davResponse.href
+        let name = davResponse.prop["displayname"] ?? davResponse.href.lastPathComponent
+        let relativePath = href.relativePath
+        let path = relativePath.hasPrefix("/") ? relativePath : ("/" + relativePath)
+        super.init(url: href, name: name, path: path)
+        self.size = Int64(davResponse.prop["getcontentlength"] ?? "-1") ?? NSURLSessionTransferSizeUnknown
+        self.creationDate = Date(rfcString: davResponse.prop["creationdate"] ?? "")
+        self.modifiedDate = Date(rfcString: davResponse.prop["getlastmodified"] ?? "")
+        self.contentType = davResponse.prop["getcontenttype"] ?? "octet/stream"
+        self.isHidden = (Int(davResponse.prop["ishidden"] ?? "0") ?? 0) > 0
+        self.type = self.contentType == "httpd/unix-directory" ? .directory : .regular
+        self.entryTag = davResponse.prop["getetag"]
+    }
    
-    public var description: String {
-        return code.description
+    /// MIME type of the file.
+    open internal(set) var contentType: String {
+        get {
+            return allValues[.mimeTypeKey] as? String ?? ""
+        }
+        set {
+            allValues[.mimeTypeKey] = newValue
+        }
+    }
+    
+    /// HTTP E-Tag, can be used to mark changed files.
+    open internal(set) var entryTag: String? {
+        get {
+            return allValues[.entryTagKey] as? String
+        }
+        set {
+            allValues[.entryTagKey] = newValue
+        }
+    }
+    
+    internal class func resourceKeyToDAVProp(_ key: URLResourceKey) -> String? {
+        switch key {
+        case URLResourceKey.fileSizeKey:
+            return "getcontentlength"
+        case URLResourceKey.creationDateKey:
+            return "creationdate"
+        case URLResourceKey.contentModificationDateKey:
+            return "getlastmodified"
+        case URLResourceKey.fileResourceTypeKey, URLResourceKey.mimeTypeKey:
+            return "getcontenttype"
+        case URLResourceKey.isHiddenKey:
+            return "ishidden"
+        case URLResourceKey.entryTagKey:
+            return "getetag"
+        default:
+            return nil
+        }
+    }
+    
+    internal class func propString(_ keys: [URLResourceKey]) -> String {
+        var propKeys = ""
+        for item in keys {
+            if let prop = WebDavFileObject.resourceKeyToDAVProp(item) {
+                propKeys += "<D:prop><D:\(prop)/></D:prop>"
+            }
+        }
+        if propKeys.isEmpty {
+            propKeys = "<D:allprop/>"
+        }
+        return propKeys
    }
 }
+
+/// Error returned by WebDAV server when trying to access or do operations on a file or folder.
+public struct FileProviderWebDavError: FileProviderHTTPError {
+    public let code: FileProviderHTTPErrorCode
+    public let path: String
+    public let errorDescription: String?
+    /// URL of resource caused error.
+    public let url: URL
+}