Fixed project name in schemes

- removed redundant protocol conforming

.travis.yml

@@ -12,8 +12,8 @@ env:
   - 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="YES" CARTHAGEDEPLOY="NO"
-    - DESTINATION="OS=9.0,name=iPhone 6"           SCHEME="$IOS_FRAMEWORK_SCHEME"     SDK="$IOS_SDK"     RUN_TESTS="NO" BUILD_EXAMPLE="NO" POD="NO"  CARTHAGEDEPLOY="YES"
+    - 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"
@@ -56,7 +56,7 @@ script:
 after_success:
   # Run `pod trunk push` if specified
   - if [ $POD == "YES" ] && [ -n "$TRAVIS_TAG" ]; then
-      pod trunk push;
+      pod trunk push --allow-warnings;
     fi
 
 #   - bash <(curl -s https://codecov.io/bash)

FilesProvider.podspec

@@ -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      = "0.14.4"
-  s.summary      = "FileManager replacement for Local and Remote (WebDAV/Dropbox/OneDrive/SMB2) files on iOS and macOS."
+  s.name         = "FilesProvider"
+  s.version      = "0.18.0"
+  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?

FilesProvider.xcodeproj/project.pbxproj

@@ -35,6 +35,9 @@
 		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 */; };
@@ -50,6 +53,7 @@
 		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 */; };
 		799396AB1D48C02300086753 /* DropboxFileProvider.swift in Sources */ = {isa = PBXBuildFile; fileRef = 799396931D48C02300086753 /* DropboxFileProvider.swift */; };
 		799396AC1D48C02300086753 /* DropboxFileProvider.swift in Sources */ = {isa = PBXBuildFile; fileRef = 799396931D48C02300086753 /* DropboxFileProvider.swift */; };
@@ -112,12 +116,14 @@
 		79BD63BE1E2CC3C20035128C /* ImageIO.framework in Frameworks */ = {isa = PBXBuildFile; fileRef = 79BD63BD1E2CC3C20035128C /* ImageIO.framework */; };
 		79BD63C01E2CC3CD0035128C /* CoreGraphics.framework in Frameworks */ = {isa = PBXBuildFile; fileRef = 79BD63BF1E2CC3CD0035128C /* CoreGraphics.framework */; };
 		79BD63C21E2CC3D30035128C /* AVFoundation.framework in Frameworks */ = {isa = PBXBuildFile; fileRef = 79BD63C11E2CC3D30035128C /* AVFoundation.framework */; };
-		79BD63C51E2D17880035128C /* OneDriveFileProvide.swift in Sources */ = {isa = PBXBuildFile; fileRef = 79BD63C31E2D17880035128C /* OneDriveFileProvide.swift */; };
-		79BD63C61E2D17880035128C /* OneDriveFileProvide.swift in Sources */ = {isa = PBXBuildFile; fileRef = 79BD63C31E2D17880035128C /* OneDriveFileProvide.swift */; };
-		79BD63C71E2D17880035128C /* OneDriveFileProvide.swift in Sources */ = {isa = PBXBuildFile; fileRef = 79BD63C31E2D17880035128C /* OneDriveFileProvide.swift */; };
+		79BD63C51E2D17880035128C /* OneDriveFileProvider.swift in Sources */ = {isa = PBXBuildFile; fileRef = 79BD63C31E2D17880035128C /* OneDriveFileProvider.swift */; };
+		79BD63C61E2D17880035128C /* OneDriveFileProvider.swift in Sources */ = {isa = PBXBuildFile; fileRef = 79BD63C31E2D17880035128C /* OneDriveFileProvider.swift */; };
+		79BD63C71E2D17880035128C /* OneDriveFileProvider.swift in Sources */ = {isa = PBXBuildFile; fileRef = 79BD63C31E2D17880035128C /* OneDriveFileProvider.swift */; };
 		79BD63C81E2D17880035128C /* OneDriveHelper.swift in Sources */ = {isa = PBXBuildFile; fileRef = 79BD63C41E2D17880035128C /* OneDriveHelper.swift */; };
 		79BD63C91E2D17880035128C /* OneDriveHelper.swift in Sources */ = {isa = PBXBuildFile; fileRef = 79BD63C41E2D17880035128C /* OneDriveHelper.swift */; };
 		79BD63CA1E2D17880035128C /* OneDriveHelper.swift in Sources */ = {isa = PBXBuildFile; fileRef = 79BD63C41E2D17880035128C /* OneDriveHelper.swift */; };
+		79F4678B1E8B80F200C91A85 /* FTPHelper.swift in Sources */ = {isa = PBXBuildFile; fileRef = 798654321E8874BC002FA550 /* FTPHelper.swift */; };
+		79F4678C1E8B80F200C91A85 /* FTPHelper.swift in Sources */ = {isa = PBXBuildFile; fileRef = 798654321E8874BC002FA550 /* FTPHelper.swift */; };
 		79F5745B1DFDB10B00179ABF /* FileObject.swift in Sources */ = {isa = PBXBuildFile; fileRef = 79F5745A1DFDB10A00179ABF /* FileObject.swift */; };
 		79F5745C1DFDB10B00179ABF /* FileObject.swift in Sources */ = {isa = PBXBuildFile; fileRef = 79F5745A1DFDB10A00179ABF /* FileObject.swift */; };
 		79F5745D1DFDB10B00179ABF /* FileObject.swift in Sources */ = {isa = PBXBuildFile; fileRef = 79F5745A1DFDB10A00179ABF /* FileObject.swift */; };
@@ -133,14 +139,16 @@
 		7924B1921D89DAE000589DB7 /* Parser.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = Parser.swift; sourceTree = "<group>"; };
 		7924B1A81D89F79200589DB7 /* FPSStreamTask.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = FPSStreamTask.swift; sourceTree = "<group>"; };
 		792572401DF23BDA006A1526 /* LocalHelper.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = LocalHelper.swift; sourceTree = "<group>"; };
+		7936BC111E880F5700A6C81C /* FTPFileProvider.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = FTPFileProvider.swift; sourceTree = "<group>"; };
 		79480FF51E3ABDD0007E7275 /* CloudFileProvider.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = CloudFileProvider.swift; sourceTree = "<group>"; };
 		794C21FD1D58912A00EC49B8 /* DropboxHelper.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = DropboxHelper.swift; sourceTree = "<group>"; };
 		794C22091D5893F800EC49B8 /* SMB2Notification.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = SMB2Notification.swift; sourceTree = "<group>"; };
 		794C220D1D591A4B00EC49B8 /* SMB2QueryTypes.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = SMB2QueryTypes.swift; sourceTree = "<group>"; };
 		796807541E7BF17E00BBB87B /* FileProviderExtensions.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = FileProviderExtensions.swift; sourceTree = "<group>"; };
-		799396671D48B7F600086753 /* FileProvider.framework */ = {isa = PBXFileReference; explicitFileType = wrapper.framework; includeInIndex = 0; path = FileProvider.framework; sourceTree = BUILT_PRODUCTS_DIR; };
-		799396751D48B80D00086753 /* FileProvider.framework */ = {isa = PBXFileReference; explicitFileType = wrapper.framework; includeInIndex = 0; path = FileProvider.framework; sourceTree = BUILT_PRODUCTS_DIR; };
-		799396821D48B82700086753 /* FileProvider.framework */ = {isa = PBXFileReference; explicitFileType = wrapper.framework; includeInIndex = 0; path = FileProvider.framework; sourceTree = BUILT_PRODUCTS_DIR; };
+		798654321E8874BC002FA550 /* FTPHelper.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = FTPHelper.swift; sourceTree = "<group>"; };
+		799396671D48B7F600086753 /* FilesProvider.framework */ = {isa = PBXFileReference; explicitFileType = wrapper.framework; includeInIndex = 0; path = FilesProvider.framework; sourceTree = BUILT_PRODUCTS_DIR; };
+		799396751D48B80D00086753 /* FilesProvider.framework */ = {isa = PBXFileReference; explicitFileType = wrapper.framework; includeInIndex = 0; path = FilesProvider.framework; sourceTree = BUILT_PRODUCTS_DIR; };
+		799396821D48B82700086753 /* FilesProvider.framework */ = {isa = PBXFileReference; explicitFileType = wrapper.framework; includeInIndex = 0; path = FilesProvider.framework; sourceTree = BUILT_PRODUCTS_DIR; };
 		7993968B1D48B8C700086753 /* Info-iOS.plist */ = {isa = PBXFileReference; lastKnownFileType = text.plist.xml; path = "Info-iOS.plist"; sourceTree = "<group>"; };
 		7993968C1D48B8C700086753 /* Info-MacOS.plist */ = {isa = PBXFileReference; lastKnownFileType = text.plist.xml; path = "Info-MacOS.plist"; sourceTree = "<group>"; };
 		7993968D1D48B8C700086753 /* Info-tvOS.plist */ = {isa = PBXFileReference; lastKnownFileType = text.plist.xml; path = "Info-tvOS.plist"; sourceTree = "<group>"; };
@@ -174,7 +182,7 @@
 		79BD63BD1E2CC3C20035128C /* ImageIO.framework */ = {isa = PBXFileReference; lastKnownFileType = wrapper.framework; name = ImageIO.framework; path = Platforms/AppleTVOS.platform/Developer/SDKs/AppleTVOS10.1.sdk/System/Library/Frameworks/ImageIO.framework; sourceTree = DEVELOPER_DIR; };
 		79BD63BF1E2CC3CD0035128C /* CoreGraphics.framework */ = {isa = PBXFileReference; lastKnownFileType = wrapper.framework; name = CoreGraphics.framework; path = Platforms/AppleTVOS.platform/Developer/SDKs/AppleTVOS10.1.sdk/System/Library/Frameworks/CoreGraphics.framework; sourceTree = DEVELOPER_DIR; };
 		79BD63C11E2CC3D30035128C /* AVFoundation.framework */ = {isa = PBXFileReference; lastKnownFileType = wrapper.framework; name = AVFoundation.framework; path = Platforms/AppleTVOS.platform/Developer/SDKs/AppleTVOS10.1.sdk/System/Library/Frameworks/AVFoundation.framework; sourceTree = DEVELOPER_DIR; };
-		79BD63C31E2D17880035128C /* OneDriveFileProvide.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = OneDriveFileProvide.swift; sourceTree = "<group>"; };
+		79BD63C31E2D17880035128C /* OneDriveFileProvider.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = OneDriveFileProvider.swift; sourceTree = "<group>"; };
 		79BD63C41E2D17880035128C /* OneDriveHelper.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = OneDriveHelper.swift; sourceTree = "<group>"; };
 		79F5745A1DFDB10A00179ABF /* FileObject.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = FileObject.swift; sourceTree = "<group>"; };
 /* End PBXFileReference section */
@@ -261,9 +269,9 @@
 		799396681D48B7F600086753 /* Products */ = {
 			isa = PBXGroup;
 			children = (
-				799396671D48B7F600086753 /* FileProvider.framework */,
-				799396751D48B80D00086753 /* FileProvider.framework */,
-				799396821D48B82700086753 /* FileProvider.framework */,
+				799396671D48B7F600086753 /* FilesProvider.framework */,
+				799396751D48B80D00086753 /* FilesProvider.framework */,
+				799396821D48B82700086753 /* FilesProvider.framework */,
 			);
 			name = Products;
 			sourceTree = "<group>";
@@ -294,7 +302,9 @@
 				7902C0851D61B56D00564440 /* RemoteSession.swift */,
 				799396931D48C02300086753 /* DropboxFileProvider.swift */,
 				794C21FD1D58912A00EC49B8 /* DropboxHelper.swift */,
-				79BD63C31E2D17880035128C /* OneDriveFileProvide.swift */,
+				7936BC111E880F5700A6C81C /* FTPFileProvider.swift */,
+				798654321E8874BC002FA550 /* FTPHelper.swift */,
+				79BD63C31E2D17880035128C /* OneDriveFileProvider.swift */,
 				79BD63C41E2D17880035128C /* OneDriveHelper.swift */,
 				7924B1A81D89F79200589DB7 /* FPSStreamTask.swift */,
 				799396971D48C02300086753 /* SMBClient.swift */,
@@ -358,9 +368,9 @@
 /* End PBXHeadersBuildPhase section */
 
 /* Begin PBXNativeTarget section */
-		799396661D48B7F600086753 /* FileProvider iOS */ = {
+		799396661D48B7F600086753 /* FilesProvider iOS */ = {
 			isa = PBXNativeTarget;
-			buildConfigurationList = 7993966F1D48B7F600086753 /* Build configuration list for PBXNativeTarget "FileProvider iOS" */;
+			buildConfigurationList = 7993966F1D48B7F600086753 /* Build configuration list for PBXNativeTarget "FilesProvider iOS" */;
 			buildPhases = (
 				799396621D48B7F600086753 /* Sources */,
 				799396631D48B7F600086753 /* Frameworks */,
@@ -371,14 +381,14 @@
 			);
 			dependencies = (
 			);
-			name = "FileProvider iOS";
+			name = "FilesProvider iOS";
 			productName = "FileProvider iOS";
-			productReference = 799396671D48B7F600086753 /* FileProvider.framework */;
+			productReference = 799396671D48B7F600086753 /* FilesProvider.framework */;
 			productType = "com.apple.product-type.framework";
 		};
-		799396741D48B80D00086753 /* FileProvider OSX */ = {
+		799396741D48B80D00086753 /* FilesProvider OSX */ = {
 			isa = PBXNativeTarget;
-			buildConfigurationList = 7993967A1D48B80D00086753 /* Build configuration list for PBXNativeTarget "FileProvider OSX" */;
+			buildConfigurationList = 7993967A1D48B80D00086753 /* Build configuration list for PBXNativeTarget "FilesProvider OSX" */;
 			buildPhases = (
 				799396701D48B80D00086753 /* Sources */,
 				799396711D48B80D00086753 /* Frameworks */,
@@ -389,14 +399,14 @@
 			);
 			dependencies = (
 			);
-			name = "FileProvider OSX";
+			name = "FilesProvider OSX";
 			productName = "FileProvider OSX";
-			productReference = 799396751D48B80D00086753 /* FileProvider.framework */;
+			productReference = 799396751D48B80D00086753 /* FilesProvider.framework */;
 			productType = "com.apple.product-type.framework";
 		};
-		799396811D48B82700086753 /* FileProvider tvOS */ = {
+		799396811D48B82700086753 /* FilesProvider tvOS */ = {
 			isa = PBXNativeTarget;
-			buildConfigurationList = 799396871D48B82700086753 /* Build configuration list for PBXNativeTarget "FileProvider tvOS" */;
+			buildConfigurationList = 799396871D48B82700086753 /* Build configuration list for PBXNativeTarget "FilesProvider tvOS" */;
 			buildPhases = (
 				7993967D1D48B82700086753 /* Sources */,
 				7993967E1D48B82700086753 /* Frameworks */,
@@ -407,9 +417,9 @@
 			);
 			dependencies = (
 			);
-			name = "FileProvider tvOS";
+			name = "FilesProvider tvOS";
 			productName = "FileProvider tvOS";
-			productReference = 799396821D48B82700086753 /* FileProvider.framework */;
+			productReference = 799396821D48B82700086753 /* FilesProvider.framework */;
 			productType = "com.apple.product-type.framework";
 		};
 /* End PBXNativeTarget section */
@@ -432,7 +442,7 @@
 					};
 				};
 			};
-			buildConfigurationList = 7993965F1D48B7BF00086753 /* Build configuration list for PBXProject "FileProvider" */;
+			buildConfigurationList = 7993965F1D48B7BF00086753 /* Build configuration list for PBXProject "FilesProvider" */;
 			compatibilityVersion = "Xcode 3.2";
 			developmentRegion = English;
 			hasScannedForEncodings = 0;
@@ -444,9 +454,9 @@
 			projectDirPath = "";
 			projectRoot = "";
 			targets = (
-				799396661D48B7F600086753 /* FileProvider iOS */,
-				799396741D48B80D00086753 /* FileProvider OSX */,
-				799396811D48B82700086753 /* FileProvider tvOS */,
+				799396661D48B7F600086753 /* FilesProvider iOS */,
+				799396741D48B80D00086753 /* FilesProvider OSX */,
+				799396811D48B82700086753 /* FilesProvider tvOS */,
 			);
 		};
 /* End PBXProject section */
@@ -485,12 +495,14 @@
 				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 /* OneDriveFileProvide.swift in Sources */,
+				79BD63C51E2D17880035128C /* OneDriveFileProvider.swift in Sources */,
 				7924B1991D89DAE000589DB7 /* Element.swift in Sources */,
 				799396C81D48C02300086753 /* SMB2IOCtl.swift in Sources */,
 				799396D71D48C02300086753 /* SMB2Types.swift in Sources */,
+				798654331E8874BC002FA550 /* FTPHelper.swift in Sources */,
 				7924B1B21D89FCDA00589DB7 /* FPSStreamTask.swift in Sources */,
 				799396C51D48C02300086753 /* SMB2FileOperation.swift in Sources */,
 				79BD63C81E2D17880035128C /* OneDriveHelper.swift in Sources */,
@@ -526,12 +538,14 @@
 				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 /* OneDriveFileProvide.swift in Sources */,
+				79BD63C61E2D17880035128C /* OneDriveFileProvider.swift in Sources */,
 				7924B1B01D89F7DE00589DB7 /* FPSStreamTask.swift in Sources */,
 				7924B19A1D89DAE000589DB7 /* Element.swift in Sources */,
 				799396C91D48C02300086753 /* SMB2IOCtl.swift in Sources */,
+				79F4678B1E8B80F200C91A85 /* FTPHelper.swift in Sources */,
 				799396D81D48C02300086753 /* SMB2Types.swift in Sources */,
 				799396C61D48C02300086753 /* SMB2FileOperation.swift in Sources */,
 				79BD63C91E2D17880035128C /* OneDriveHelper.swift in Sources */,
@@ -567,12 +581,14 @@
 				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 /* OneDriveFileProvide.swift in Sources */,
+				79BD63C71E2D17880035128C /* OneDriveFileProvider.swift in Sources */,
 				7924B1B11D89F7DF00589DB7 /* FPSStreamTask.swift in Sources */,
 				7924B19B1D89DAE000589DB7 /* Element.swift in Sources */,
 				799396CA1D48C02300086753 /* SMB2IOCtl.swift in Sources */,
+				79F4678C1E8B80F200C91A85 /* FTPHelper.swift in Sources */,
 				799396D91D48C02300086753 /* SMB2Types.swift in Sources */,
 				799396C71D48C02300086753 /* SMB2FileOperation.swift in Sources */,
 				79BD63CA1E2D17880035128C /* OneDriveHelper.swift in Sources */,
@@ -605,7 +621,7 @@
 		799396601D48B7BF00086753 /* Debug */ = {
 			isa = XCBuildConfiguration;
 			buildSettings = {
-				BUNDLE_VERSION_STRING = 0.14.4;
+				BUNDLE_VERSION_STRING = 0.18.0;
 				CLANG_WARN_BOOL_CONVERSION = YES;
 				CLANG_WARN_CONSTANT_CONVERSION = YES;
 				CLANG_WARN_EMPTY_BODY = YES;
@@ -615,6 +631,7 @@
 				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;
@@ -628,6 +645,7 @@
 				GCC_WARN_UNUSED_FUNCTION = YES;
 				GCC_WARN_UNUSED_VARIABLE = YES;
 				ONLY_ACTIVE_ARCH = YES;
+				PRODUCT_NAME = FilesProvider;
 				SWIFT_VERSION = 3.0;
 			};
 			name = Debug;
@@ -635,7 +653,7 @@
 		799396611D48B7BF00086753 /* Release */ = {
 			isa = XCBuildConfiguration;
 			buildSettings = {
-				BUNDLE_VERSION_STRING = 0.14.4;
+				BUNDLE_VERSION_STRING = 0.18.0;
 				CLANG_WARN_BOOL_CONVERSION = YES;
 				CLANG_WARN_CONSTANT_CONVERSION = YES;
 				CLANG_WARN_EMPTY_BODY = YES;
@@ -655,6 +673,7 @@
 				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;
 			};
@@ -665,7 +684,6 @@
 			buildSettings = {
 				ALWAYS_SEARCH_USER_PATHS = NO;
 				APPLICATION_EXTENSION_API_ONLY = YES;
-				BUNDLE_VERSION_STRING = 0.8.2;
 				CLANG_ANALYZER_NONNULL = YES;
 				CLANG_ENABLE_MODULES = YES;
 				CLANG_ENABLE_OBJC_ARC = YES;
@@ -702,8 +720,7 @@
 				IPHONEOS_DEPLOYMENT_TARGET = 8.0;
 				LD_RUNPATH_SEARCH_PATHS = "$(inherited) @executable_path/Frameworks @loader_path/Frameworks";
 				MTL_ENABLE_DEBUG_INFO = YES;
-				PRODUCT_BUNDLE_IDENTIFIER = "com.mousavian.FileProvider-iOS";
-				PRODUCT_NAME = FileProvider;
+				PRODUCT_BUNDLE_IDENTIFIER = "com.mousavian.FilesProvider-iOS";
 				SDKROOT = iphoneos;
 				SKIP_INSTALL = YES;
 				SWIFT_OPTIMIZATION_LEVEL = "-Onone";
@@ -718,7 +735,6 @@
 			buildSettings = {
 				ALWAYS_SEARCH_USER_PATHS = NO;
 				APPLICATION_EXTENSION_API_ONLY = YES;
-				BUNDLE_VERSION_STRING = 0.8.2;
 				CLANG_ANALYZER_NONNULL = YES;
 				CLANG_ENABLE_MODULES = YES;
 				CLANG_ENABLE_OBJC_ARC = YES;
@@ -750,8 +766,7 @@
 				IPHONEOS_DEPLOYMENT_TARGET = 8.0;
 				LD_RUNPATH_SEARCH_PATHS = "$(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";
@@ -807,8 +822,7 @@
 				LD_RUNPATH_SEARCH_PATHS = "$(inherited) @executable_path/../Frameworks @loader_path/Frameworks";
 				MACOSX_DEPLOYMENT_TARGET = 10.10;
 				MTL_ENABLE_DEBUG_INFO = YES;
-				PRODUCT_BUNDLE_IDENTIFIER = "com.mousavian.FileProvider-OSX";
-				PRODUCT_NAME = FileProvider;
+				PRODUCT_BUNDLE_IDENTIFIER = "com.mousavian.FilesProvider-OSX";
 				SDKROOT = macosx;
 				SKIP_INSTALL = YES;
 				SWIFT_OPTIMIZATION_LEVEL = "-Onone";
@@ -858,8 +872,7 @@
 				LD_RUNPATH_SEARCH_PATHS = "$(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";
@@ -910,8 +923,7 @@
 				INSTALL_PATH = "$(LOCAL_LIBRARY_DIR)/Frameworks";
 				LD_RUNPATH_SEARCH_PATHS = "$(inherited) @executable_path/Frameworks @loader_path/Frameworks";
 				MTL_ENABLE_DEBUG_INFO = 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";
@@ -960,8 +972,7 @@
 				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;
@@ -975,7 +986,7 @@
 /* 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 */,
@@ -984,7 +995,7 @@
 			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 */,
@@ -993,7 +1004,7 @@
 			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 */,
@@ -1002,7 +1013,7 @@
 			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 */,

FilesProvider.xcodeproj/xcshareddata/xcschemes/FilesProvider OSX.xcscheme

@@ -1,6 +1,6 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <Scheme
-   LastUpgradeVersion = "0810"
+   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>

FilesProvider.xcodeproj/xcshareddata/xcschemes/FilesProvider iOS.xcscheme

@@ -1,6 +1,6 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <Scheme
-   LastUpgradeVersion = "0810"
+   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>

FilesProvider.xcodeproj/xcshareddata/xcschemes/FilesProvider tvOS.xcscheme

@@ -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>

README.md

@@ -20,15 +20,17 @@
 [![codecov](https://codecov.io/gh/amosavian/FileProvider/branch/master/graph/badge.svg)](https://codecov.io/gh/amosavian/FileProvider) 
 ---> 
 
-This library provides implementaion of WebDav, Dropbox, OneDrive 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.
+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] **CloudFileProvider** A wrapper around app's ubiquitous container to iCloud Drive in iOS 8+ API.
-- [x] **WebDAVFileProvider** WebDAV protocol is defacto file transmission standard, replaced FTP.
+- [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.
+    * Active mode is not implemented yet.
 - [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.
@@ -37,25 +39,27 @@ All functions are async calls and it wont block your main thread.
 - [ ] **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!*.
-    * SMB1/CIFS is deprecated and very tricky to be implemented.
-- [ ] **FTPFileProvider** while deprecated in 1990s, it's still in use on some Web hosts.
+    * SMB1/CIFS is deprecated and very tricky to be implemented due to strict memory allignment in Swift.
 
 ## Requirements
 
-- **Swift 3.0 +**
+- **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
 
+###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.
+
+
 ### Cocoapods / Carthage / Swift Package Manager
 
 Add this line to your pods file:
 
 ```ruby
-pod "FileProvider"
+pod "FilesProvider"
 ```
 
 Or add this to Cartfile:
@@ -67,7 +71,7 @@ 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, minorVersion: 12)
+.Package(url: "https://github.com/amosavian/FileProvider.git", majorVersion: 0)
 ```
 
 ### Manually
@@ -93,7 +97,7 @@ Then you can do either:
 
 * Copy Source folder to your project and Voila!
 
-* Drop `FileProvider.xcodeproj` to you Xcode workspace and add the framework to your Embeded Binaries in target.
+* Drop `FilesProvider.xcodeproj` to you Xcode workspace and add the framework to your Embeded Binaries in target.
 
 ## Usage
 
@@ -104,6 +108,8 @@ Each provider has a specific class which conforms to FileProvider protocol and s
 For LocalFileProvider if you want to deal with `Documents` folder
 
 ```	swift
+import FilesProvider
+
 let documentsProvider = LocalFileProvider()
 
 // Equals with:
@@ -117,6 +123,8 @@ 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
 ```
@@ -126,6 +134,8 @@ You can't change the base url later. and all paths are related to this base url
 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)
 ```
 
@@ -133,6 +143,8 @@ let documentsProvider = CloudFileProvider(containerId: nil)
 For remote file providers authentication may be necessary:
 
 ```	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)
 ```
@@ -149,7 +161,7 @@ You can use `url(of:)` method if provider to get direct access url (local or rem
 
 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:
 
@@ -202,7 +214,7 @@ 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
 
@@ -271,12 +283,7 @@ documentsProvider.create(folder: "new folder", at: "/", completionHandler: { err
 })
 ```
 
-Creating new file from data:
-
-```swift
-let data = "hello world!".data(encoding: .utf8)
-documentsProvider.create(file: "newFile.txt", at: "/", contents: data, completionHandler: nil)
-```
+To create a file, use `writeContents(path:, content:, atomically:, completionHandler:)` method.
 
 ### Copy and Move/Rename Files
 
@@ -300,11 +307,11 @@ documentsProvider.moveItem(path: "new folder/old.txt", to: "new.txt", overwrite:
 documentsProvider.removeItem(path: "new.txt", completionHandler: nil)
 ```
 
-***Caution:*** This method will delete directories with all it's contents recursively.
+***Caution:*** This method will delete directories with all it's contents recursively except for FTP providers that don't support `SITE RMDIR` command, this will be fixed later.
 
 ### Fetching Contents 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.
+There is two method for this purpose, one of them loads entire file into `Data` and another can load a portion of file.
 
 ```swift
 documentsProvider.contents(path: "old.txt", completionHandler: {
@@ -333,6 +340,27 @@ let data = "What's up Newyork!".data(encoding: .utf8)
 documentsProvider.writeContents(path: "old.txt", content: data, atomically: true, completionHandler: nil)
 ```
 
+### Copying Files to and From Local URL
+
+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.
+
+To upload a file:
+
+```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.
+
 ### 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:
@@ -382,6 +410,10 @@ Creating/Copying/Deleting functions return a `OperationHandle` for remote operat
 
 It's not supported by native `(NS)FileManager` so `LocalFileProvider`, but this functionality will be added to future `PosixFileProvider` class.
 
+### 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.
@@ -439,9 +471,10 @@ if documentsProvider..propertiesOfFile(path: file.path, completionHandler: { (pr
 
 We would love for you to contribute to **FileProvider**, check the `LICENSE` file for more info.
 
-Things to do:
+Things you may consider to help us:
 
-- [ ] Implement Test-case (XCTest)
+- [ ] Implement request/response stack for `SMBClient`
+- [ ] Implement Test-case (`XCTest`)
 - [ ] Add Sample project for iOS
 - [ ] Add Sample project for macOS
 
@@ -463,7 +496,7 @@ Distributed under the MIT license. See `LICENSE` for more information.
 [https://github.com/amosavian/](https://github.com/amosavian/)
 
 [cocoapods]: https://cocoapods.org/pods/FileProvider
-[swift-image]: https://img.shields.io/badge/swift-3.0-orange.svg
+[swift-image]: https://img.shields.io/badge/swift-3.0,%203.1-orange.svg
 [swift-url]: https://swift.org/
 [platform-image]: https://img.shields.io/cocoapods/p/FileProvider.svg
 [license-image]: https://img.shields.io/github/license/amosavian/FileProvider.svg

Sources/AEXML/LICENSE

@@ -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.

Sources/CloudFileProvider.swift

@@ -15,7 +15,7 @@ import Foundation
  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 {
+open class CloudFileProvider: LocalFileProvider, FileProviderSharing {
     /// An string to identify type of provider.
     open override class var type: String { return "iCloudDrive" }
     
@@ -71,9 +71,14 @@ open class CloudFileProvider: LocalFileProvider {
         super.init(baseURL: baseURL)
         self.isCoorinating = true
         
-        dispatch_queue = DispatchQueue(label: "FileProvider.\(type(of: self).type)", attributes: .concurrent)
+        #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 = "FileProvider.\(type(of: self).type).Operation"
+        operation_queue.name = "\(queueLabel).Operation"
         
         fileManager.url(forUbiquityContainerIdentifier: containerId)
         opFileManager.url(forUbiquityContainerIdentifier: containerId)
@@ -81,6 +86,33 @@ open class CloudFileProvider: LocalFileProvider {
         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.
      
@@ -101,7 +133,7 @@ open class CloudFileProvider: LocalFileProvider {
             query.valueListAttributes = [NSMetadataItemURLKey, NSMetadataItemFSNameKey, NSMetadataItemPathKey, NSMetadataItemFSSizeKey, NSMetadataItemContentTypeTreeKey, NSMetadataItemFSCreationDateKey, NSMetadataItemFSContentChangeDateKey]
             query.searchScopes = [self.scope.rawValue]
             var finishObserver: NSObjectProtocol?
-            finishObserver = NotificationCenter.default.addObserver(forName: NSNotification.Name.NSMetadataQueryDidFinishGathering, object: query, queue: nil, using: { (notification) in
+            finishObserver = NotificationCenter.default.addObserver(forName: .NSMetadataQueryDidFinishGathering, object: query, queue: nil, using: { (notification) in
                 defer {
                     query.stop()
                     NotificationCenter.default.removeObserver(finishObserver!)
@@ -168,7 +200,7 @@ open class CloudFileProvider: LocalFileProvider {
             query.valueListAttributes = [NSMetadataItemURLKey, NSMetadataItemFSNameKey, NSMetadataItemPathKey, NSMetadataItemFSSizeKey, NSMetadataItemContentTypeTreeKey, NSMetadataItemFSCreationDateKey, NSMetadataItemFSContentChangeDateKey]
             query.searchScopes = [self.scope.rawValue]
             var finishObserver: NSObjectProtocol?
-            finishObserver = NotificationCenter.default.addObserver(forName: NSNotification.Name.NSMetadataQueryDidFinishGathering, object: query, queue: nil, using: { (notification) in
+            finishObserver = NotificationCenter.default.addObserver(forName: .NSMetadataQueryDidFinishGathering, object: query, queue: nil, using: { (notification) in
                 defer {
                     query.stop()
                     NotificationCenter.default.removeObserver(finishObserver!)
@@ -347,25 +379,7 @@ open class CloudFileProvider: LocalFileProvider {
      */
     @discardableResult
     open override func create(folder folderName: String, at atPath: String, completionHandler: SimpleCompletionHandler) -> OperationHandle? {
-        guard let r = super.create(folder: folderName, at: atPath, completionHandler: completionHandler) else { return nil }
-        return CloudOperationHandle(operationType: r.operationType, baseURL: self.baseURL)
-    }
-    
-    /**
-     Creates an new file with data passed to method asynchronously.
-     Returns error via completionHandler if file is already exists.
-     
-     - Parameters:
-       - file: New file name with extension separated by period.
-       - at: Parent path of new file.
-       - data: Data of new files. Pass nil or `Data()` to create empty file.
-       - completionHandler: If an error parameter was provided, a presentable `Error` will be returned.
-     - Returns: An `OperationHandle` to get progress or cancel progress. Doesn't work on `CloudFileProvider`.
-     */
-    @discardableResult
-    open override func create(file fileName: String, at atPath: String, contents data: Data?, completionHandler: SimpleCompletionHandler) -> OperationHandle? {
-        guard let r = super.create(file: fileName, at: atPath, contents: data, completionHandler: completionHandler) else { return nil }
-        return CloudOperationHandle(operationType: r.operationType, baseURL: self.baseURL)
+        return super.create(folder: folderName, at: atPath, completionHandler: completionHandler)
     }
     
     /**
@@ -382,8 +396,7 @@ open class CloudFileProvider: LocalFileProvider {
      */
     @discardableResult
     open override func moveItem(path: String, to toPath: String, overwrite: Bool = false, completionHandler: SimpleCompletionHandler) -> OperationHandle? {
-        guard let r = super.moveItem(path: path, to: toPath, overwrite: overwrite, completionHandler: completionHandler) else { return nil }
-        return CloudOperationHandle(operationType: r.operationType, baseURL: self.baseURL)
+        return super.moveItem(path: path, to: toPath, overwrite: overwrite, completionHandler: completionHandler)
     }
     
     /**
@@ -400,8 +413,7 @@ open class CloudFileProvider: LocalFileProvider {
      */
     @discardableResult
     open override func copyItem(path: String, to toPath: String, overwrite: Bool = false, completionHandler: SimpleCompletionHandler) -> OperationHandle? {
-        guard let r = super.copyItem(path: path, to: toPath, overwrite: overwrite, completionHandler: completionHandler) else { return nil }
-        return CloudOperationHandle(operationType: r.operationType, baseURL: self.baseURL)
+        return super.copyItem(path: path, to: toPath, overwrite: overwrite, completionHandler: completionHandler)
     }
     
     /**
@@ -419,8 +431,7 @@ open class CloudFileProvider: LocalFileProvider {
      */
     @discardableResult
     open override func removeItem(path: String, completionHandler: SimpleCompletionHandler) -> OperationHandle? {
-        guard let r = super.removeItem(path: path, completionHandler: completionHandler) else { return nil }
-        return CloudOperationHandle(operationType: r.operationType, baseURL: self.baseURL)
+        return super.removeItem(path: path, completionHandler: completionHandler)
     }
     
     /**
@@ -438,6 +449,7 @@ open class CloudFileProvider: LocalFileProvider {
     open override func copyItem(localFile: URL, to toPath: String, overwrite: Bool, completionHandler: SimpleCompletionHandler) -> OperationHandle? {
         // TODO: Make use of overwrite parameter
         let opType = FileOperationType.copy(source: localFile.absoluteString, destination: toPath)
+        let operationHandle =  CloudOperationHandle(operationType: opType, baseURL: self.baseURL)
         operation_queue.addOperation {
             let tempFolder: URL
             if #available(iOS 10.0, macOS 10.12, tvOS 10.0, *) {
@@ -465,7 +477,7 @@ open class CloudFileProvider: LocalFileProvider {
                 })
             }
         }
-        return CloudOperationHandle(operationType: opType, baseURL: self.baseURL)
+        return operationHandle
     }
     
     /**
@@ -491,9 +503,8 @@ open class CloudFileProvider: LocalFileProvider {
             })
             return nil
         }
-        
-        guard let r = super.copyItem(path: path, toLocalURL: toLocalURL, completionHandler: completionHandler) else { return nil }
-        return CloudOperationHandle(operationType: r.operationType, baseURL: self.baseURL)
+        let handle = super.copyItem(path: path, toLocalURL: toLocalURL, completionHandler: completionHandler)
+        return handle
     }
     
     /**
@@ -509,8 +520,7 @@ open class CloudFileProvider: LocalFileProvider {
      */
     @discardableResult
     open override func contents(path: String, completionHandler: @escaping ((_ contents: Data?, _ error: Error?) -> Void)) -> OperationHandle? {
-        guard let r = super.contents(path: path, completionHandler: completionHandler) else { return nil }
-        return CloudOperationHandle(operationType: r.operationType, baseURL: self.baseURL)
+        return super.contents(path: path, completionHandler: completionHandler)
     }
     
     /**
@@ -528,8 +538,7 @@ open class CloudFileProvider: LocalFileProvider {
      */
     @discardableResult
     open override func contents(path: String, offset: Int64, length: Int, completionHandler: @escaping ((_ contents: Data?, _ error: Error?) -> Void)) -> OperationHandle? {
-        guard let r = super.contents(path: path, offset: offset, length: length, completionHandler: completionHandler) else { return nil }
-        return CloudOperationHandle(operationType: r.operationType, baseURL: self.baseURL)
+        return super.contents(path: path, offset: offset, length: length, completionHandler: completionHandler)
     }
     
     /**
@@ -544,9 +553,8 @@ open class CloudFileProvider: LocalFileProvider {
      - Returns: An `OperationHandle` 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) -> OperationHandle? {
-        guard let r = super.writeContents(path: path, contents: data, atomically: atomically, overwrite: overwrite, completionHandler: completionHandler) else { return nil }
-        return CloudOperationHandle(operationType: r.operationType, baseURL: self.baseURL)
+    open override func writeContents(path: String, contents data: Data?, atomically: Bool, overwrite: Bool, completionHandler: SimpleCompletionHandler) -> OperationHandle? {
+        return super.writeContents(path: path, contents: data, atomically: atomically, overwrite: overwrite, completionHandler: completionHandler)
     }
     
     fileprivate var monitors = [String: (NSMetadataQuery, NSObjectProtocol)]()
@@ -611,14 +619,6 @@ open class CloudFileProvider: LocalFileProvider {
         return monitors[path] != nil
     }
     
-    open override func copy(with zone: NSZone? = nil) -> Any {
-        let copy = CloudFileProvider(containerId: self.containerId)
-        copy?.currentPath = self.currentPath
-        copy?.delegate = self.delegate
-        copy?.fileOperationDelegate = self.fileOperationDelegate
-        return copy as Any
-    }
-    
     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
@@ -626,7 +626,7 @@ open class CloudFileProvider: LocalFileProvider {
         
         let path = self.relativePathOf(url: url)
         let rpath = path.hasPrefix("/") ? path.substring(from: path.index(after: path.startIndex)) : path
-        let relativeUrl = URL(string: rpath, relativeTo: self.baseURL)
+        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
@@ -639,6 +639,48 @@ open class CloudFileProvider: LocalFileProvider {
         return file
     }
     
+    func monitorFile(path: String, opType: FileOperationType) {
+        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, NSMetadataUbiquitousItemPercentDownloadedKey, NSMetadataUbiquitousItemPercentUploadedKey, NSMetadataItemFSSizeKey]
+            query.searchScopes = [self.scope.rawValue]
+            var updateObserver: NSObjectProtocol?
+            updateObserver = NotificationCenter.default.addObserver(forName: .NSMetadataQueryDidFinishGathering, object: query, queue: nil, using: { (notification) in
+                query.disableUpdates()
+                
+                guard let item = (query.results as? [NSMetadataItem])?.first else {
+                    return
+                }
+                
+                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) {
+                    DispatchQueue.main.async {
+                        self.delegate?.fileproviderProgress(self, operation: opType, progress: Float(uploaded / 100))
+                    }
+                } else if (uploaded == 0 || uploaded == 100) && (downloaded > 0 && downloaded < 100) {
+                    DispatchQueue.main.async {
+                        self.delegate?.fileproviderProgress(self, operation: opType, progress: Float(downloaded / 100))
+                    }
+                } else if uploaded == 100 || downloaded == 100 {
+                    query.stop()
+                    NotificationCenter.default.removeObserver(updateObserver!)
+                    DispatchQueue.main.async {
+                        self.delegate?.fileproviderSucceed(self, operation: opType)
+                    }
+                }
+                
+                query.enableUpdates()
+            })
+            
+            DispatchQueue.main.async {
+                query.start()
+            }
+        }
+    }
+    
     /// Removes local copy of file, but spares cloud copy/
     /// - Parameter path: Path of file or directory to be remoed from local
     /// - Parameter completionHandler: If an error parameter was provided, a presentable `Error` will be returned.
@@ -653,19 +695,6 @@ open class CloudFileProvider: LocalFileProvider {
         }
     }
     
-    /**
-     Genrates a public url to a file to be shared with other users and can be downloaded without authentication.
-     
-     - Important: URL will be available for a limitied time, determined in `expiration` argument.
-     
-     - Parameters:
-     - to: path of file, including file/directory name.
-     - completionHandler: a closure with result of directory entries or error.
-     `link`: a url returned by Dropbox to share.
-     `attribute`: a `FileObject` containing the attributes of the item.
-     `expiration`: a `Date` object, determines when the public url will expires.
-     `error`: Error returned by Dropbox.
-     */
     open func publicLink(to path: String, completionHandler: @escaping ((_ link: URL?, _ attribute: FileObject?, _ expiration: Date?, _ error: Error?) -> Void)) {
         operation_queue.addOperation {
             do {
@@ -683,6 +712,7 @@ open class CloudFileProvider: LocalFileProvider {
     }
 }
 
+/// 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 
@@ -715,8 +745,11 @@ public enum UbiquitousScope: RawRepresentable {
     }
 }
 
+/// Get progress of CloudFileProvider operations
 open class CloudOperationHandle: OperationHandle {
+    /// Url of file which operation is doing on
     public let baseURL: URL?
+    /// Type of operation
     public let operationType: FileOperationType
     
     init (operationType: FileOperationType, baseURL: URL?) {

Sources/DropboxFileProvider.swift

@@ -17,7 +17,7 @@ import CoreGraphics
  - Note: Uploading files and data are limited to 150MB, for now.
  */
 open class DropboxFileProvider: FileProviderBasicRemote {
-    open class var type: String { return "DropBox" }
+    open class var type: String { return "Dropbox" }
     open let baseURL: URL?
     open var currentPath: String
     
@@ -34,7 +34,11 @@ open class DropboxFileProvider: FileProviderBasicRemote {
     }
     
     open weak var delegate: FileProviderDelegate?
-    open let credential: URLCredential?
+    open var credential: URLCredential? {
+        didSet {
+            sessionDelegate?.credential = self.credential
+        }
+    }
     open private(set) var cache: URLCache?
     public var useCache: Bool
     public var validatingCache: Bool
@@ -42,14 +46,28 @@ open class DropboxFileProvider: FileProviderBasicRemote {
     fileprivate var _session: URLSession?
     fileprivate var sessionDelegate: SessionDelegate?
     public var session: URLSession {
-        if _session == nil {
-            self.sessionDelegate = SessionDelegate(fileProvider: self, credential: credential)
-            let config = URLSessionConfiguration.default
-            config.urlCache = cache
-            config.requestCachePolicy = .returnCacheDataElseLoad
-            _session = URLSession(configuration: config, delegate: sessionDelegate as URLSessionDelegate?, delegateQueue: self.operation_queue)
+        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!)
         }
-        return _session!
     }
     
     fileprivate var _longpollSession: URLSession?
@@ -83,18 +101,55 @@ open class DropboxFileProvider: FileProviderBasicRemote {
         self.apiURL = URL(string: "https://api.dropboxapi.com/2/")!
         self.contentURL = URL(string: "https://content.dropboxapi.com/2/")!
         
-        dispatch_queue = DispatchQueue(label: "FileProvider.\(type(of: self).type)", attributes: .concurrent)
+        #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 = "FileProvider.\(type(of: self).type).Operation"
-
+        operation_queue.name = "\(queueLabel).Operation"
+    }
+    
+    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")
+    }
+    
+    public func encode(with aCoder: NSCoder) {
+        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 {
+        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
     }
     
     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)) {
@@ -107,8 +162,8 @@ open class DropboxFileProvider: FileProviderBasicRemote {
         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")
+        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
@@ -130,7 +185,7 @@ open class DropboxFileProvider: FileProviderBasicRemote {
         let url = URL(string: "users/get_space_usage", relativeTo: apiURL)!
         var request = URLRequest(url: url)
         request.httpMethod = "POST"
-        request.setValue("Bearer \(credential?.password ?? "")", forHTTPHeaderField: "Authorization")
+        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
@@ -185,11 +240,6 @@ extension DropboxFileProvider: FileProviderOperations {
         return doOperation(.create(path: path), completionHandler: completionHandler)
     }
     
-    open func create(file fileName: String, at path: String, contents data: Data?, completionHandler: SimpleCompletionHandler) -> OperationHandle? {
-        let filePath = (path as NSString).appendingPathComponent(fileName)
-        return self.writeContents(path: filePath, contents: data ?? Data(), completionHandler: completionHandler)
-    }
-    
     open func moveItem(path: String, to toPath: String, overwrite: Bool, completionHandler: SimpleCompletionHandler) -> OperationHandle? {
         return doOperation(.move(source: path, destination: toPath), completionHandler: completionHandler)
     }
@@ -223,8 +273,8 @@ extension DropboxFileProvider: FileProviderOperations {
         }
         var request = URLRequest(url: URL(string: url, relativeTo: apiURL)!)
         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]()
         if let dest = correctPath(destPath) as NSString? {
             requestDictionary["from_path"] = correctPath(sourcePath) as NSString?
@@ -247,6 +297,14 @@ extension DropboxFileProvider: FileProviderOperations {
     }
     
     open func copyItem(localFile: URL, to toPath: String, overwrite: Bool, completionHandler: SimpleCompletionHandler) -> OperationHandle? {
+        // 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
@@ -261,26 +319,25 @@ extension DropboxFileProvider: FileProviderOperations {
         }
         let url = URL(string: "files/download", relativeTo: contentURL)!
         var request = URLRequest(url: url)
-        request.httpMethod = "GET"
-        request.setValue("Bearer \(credential?.password ?? "")", forHTTPHeaderField: "Authorization")
-        let requestDictionary: [String: AnyObject] = ["path": path as NSString]
-        let requestJson = String(jsonDictionary: requestDictionary) ?? ""
-        request.setValue(requestJson, 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)
+        request.set(httpAuthentication: credential, with: .oAuth2)
+        request.set(dropboxArgKey: ["path": path as NSString])
+        let task = session.downloadTask(with: request)
+        completionHandlersForTasks[session.sessionDescription!]?[task.taskIdentifier] = completionHandler
+        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 : FileProviderDropboxError? = code != nil ? FileProviderDropboxError(code: code!, path: path, errorDescription: String(data: errorData ?? Data(), encoding: .utf8)) : nil
-                completionHandler?(serverError ?? error)
+                completionHandler?(serverError)
                 return
             }
             do {
-                try FileManager.default.moveItem(at: cacheURL, to: destURL)
+                try FileManager.default.moveItem(at: tempURL, to: destURL)
                 completionHandler?(nil)
             } catch let e {
                 completionHandler?(e)
             }
-        })
+        }
         task.taskDescription = opType.json
         task.resume()
         return RemoteOperationHandle(operationType: opType, tasks: [task])
@@ -299,35 +356,40 @@ extension DropboxFileProvider: FileProviderReadWrite {
         let opType = FileOperationType.fetch(path: path)
         let url = URL(string: "files/download", relativeTo: contentURL)!
         var request = URLRequest(url: url)
-        request.httpMethod = "GET"
-        request.setValue("Bearer \(credential?.password ?? "")", forHTTPHeaderField: "Authorization")
-        if length > 0 {
-            request.setValue("bytes=\(offset)-\(offset + length - 1)", forHTTPHeaderField: "Range")
-        } else if offset > 0 && length < 0 {
-            request.setValue("bytes=\(offset)-", forHTTPHeaderField: "Range")
+        request.set(httpAuthentication: credential, with: .oAuth2)
+        request.set(rangeWithOffset: offset, length: length)
+        request.set(dropboxArgKey: ["path": correctPath(path)! as NSString])
+        let task = session.downloadTask(with: request)
+        completionHandlersForTasks[session.sessionDescription!]?[task.taskIdentifier] = { error in
+            completionHandler(nil, error)
         }
-        let requestDictionary: [String: AnyObject] = ["path": correctPath(path)! as NSString]
-        request.setValue(String(jsonDictionary: requestDictionary), forHTTPHeaderField: "Dropbox-API-Arg")
-        let task = session.dataTask(with: request, completionHandler: { (data, response, error) in
-            var serverError: FileProviderDropboxError?
-            if let httpResponse = response as? HTTPURLResponse , httpResponse.statusCode >= 300, let code = FileProviderHTTPErrorCode(rawValue: httpResponse.statusCode) {
-                serverError = FileProviderDropboxError(code: code, path: path, errorDescription: String(data: data ?? Data(), encoding: .utf8))
+        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 : FileProviderDropboxError? = code != nil ? FileProviderDropboxError(code: code!, path: path, errorDescription: String(data: errorData ?? Data(), encoding: .utf8)) : nil
+                completionHandler(nil, serverError)
+                return
             }
-            let filedata = serverError ?? error == nil ? data : nil
-            completionHandler(filedata, serverError ?? error)
-        })
+            do {
+                let data = try Data(contentsOf: tempURL)
+                completionHandler(data, nil)
+            } catch let e {
+                completionHandler(nil, e)
+            }
+        }
         task.taskDescription = opType.json
         task.resume()
         return RemoteOperationHandle(operationType: opType, tasks: [task])
     }
     
-    public func writeContents(path: String, contents data: Data, atomically: Bool, overwrite: Bool, completionHandler: SimpleCompletionHandler) -> OperationHandle? {
+    public func writeContents(path: String, contents data: Data?, atomically: Bool, overwrite: Bool, completionHandler: SimpleCompletionHandler) -> OperationHandle? {
         let opType = FileOperationType.modify(path: path)
         guard fileOperationDelegate?.fileProvider(self, shouldDoOperation: opType) ?? true == true else {
             return nil
         }
         // FIXME: remove 150MB restriction
-        return upload_simple(path, data: data, overwrite: overwrite, operation: opType, completionHandler: completionHandler)
+        return upload_simple(path, data: data ?? Data(), overwrite: overwrite, operation: opType, completionHandler: completionHandler)
     }
     
     /*
@@ -347,42 +409,13 @@ extension DropboxFileProvider: FileProviderReadWrite {
     // TODO: Implement /get_account & /get_current_account
 }
 
-extension DropboxFileProvider {
-    /// *DEPRECATED:* Use `publicLink(to:, completionHandler: (URL?, DropboxFileObject?, Date?,  Error?))` function instead.
-    @available(*, deprecated, renamed: "publicLink(to:completionHandler:)", message: "Use publicLink(to:, completionHandler: (URL?, DropboxFileObject?, Date?,  Error?)) function instead.")
-    open func temporaryLink(to path: String, completionHandler: @escaping ((_ link: URL?, _ attribute: DropboxFileObject?, _ error: Error?) -> Void)) {
-        self.publicLink(to: path) { (url, file, _, error) in
-            completionHandler(url, file, error)
-        }
-    }
-    
-    /// *DEPRECATED:* Use `publicLink(to:, completionHandler: (URL?, DropboxFileObject?, Date?,  Error?))` function instead.
-    @available(*, deprecated, renamed: "publicLink(to:completionHandler:)", message: "Use publicLink(to:, completionHandler: (URL?, DropboxFileObject?, Date?,  Error?)) function instead.")
-    open func temporaryLink(to path: String, completionHandler: @escaping ((_ link: URL?, _ attribute: DropboxFileObject?, _ expiration: Date?, _ error: Error?) -> Void)) {
-        self.publicLink(to: path) { (url, file, expiration, error) in
-            completionHandler(url, file, expiration, error)
-        }
-    }
-    
-    /**
-     Genrates a public url to a file to be shared with other users and can be downloaded without authentication.
-     
-     - Important: URL will be available for a limitied time (4 hours according to Dropbox documentation).
-     
-     - Parameters:
-       - to: path of file, including file/directory name.
-       - completionHandler: a closure with result of directory entries or error.
-         `link`: a url returned by Dropbox to share.
-         `attribute`: a `FileObject` containing the attributes of the item.
-         `expiration`: a `Date` object, determines when the public url will expires.
-         `error`: Error returned by Dropbox.
-    */
-    open func publicLink(to path: String, completionHandler: @escaping ((_ link: URL?, _ attribute: DropboxFileObject?, _ expiration: Date?, _ error: Error?) -> Void)) {
+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.setValue("Bearer \(credential?.password ?? "")", forHTTPHeaderField: "Authorization")
-        request.setValue("application/json", forHTTPHeaderField: "Content-Type")
+        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
@@ -415,9 +448,9 @@ extension DropboxFileProvider {
        - 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.
+         - `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 {
@@ -427,8 +460,8 @@ extension DropboxFileProvider {
         let url = URL(string: "files/save_url", 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)
         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
@@ -462,8 +495,8 @@ extension DropboxFileProvider {
         let url = URL(string: "files/copy_reference/save", 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)
         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
@@ -511,26 +544,37 @@ extension DropboxFileProvider: ExtendedFileProvider {
     /// 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: "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 = URL(string: "files/get_preview", relativeTo: contentURL)!
+            thumbAPI = false
         default:
             return
         }
         var request = URLRequest(url: url)
-        request.setValue("Bearer \(credential?.password ?? "")", forHTTPHeaderField: "Authorization")
+        request.set(httpAuthentication: credential, with: .oAuth2)
         var requestDictionary: [String: AnyObject] = ["path": path as NSString]
-        requestDictionary["format"] = "jpeg" as NSString
-        if let dimension = dimension {
-            requestDictionary["size"] = "w\(Int(dimension.width))h\(Int(dimension.height))" 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.setValue(String(jsonDictionary: requestDictionary), forHTTPHeaderField: "Dropbox-API-Arg")
+        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 = result.deserializeJSON() {
@@ -543,8 +587,12 @@ extension DropboxFileProvider: ExtendedFileProvider {
                     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 {
-                    image = ImageClass(data: data)
+                } else if let fetchedimage = ImageClass(data: data){
+                    if let dimension = dimension {
+                        image = DropboxFileProvider.scaleDown(image: fetchedimage, toSize: dimension)
+                    } else {
+                        image = fetchedimage
+                    }
                 }
             }
             completionHandler(image, error)
@@ -556,8 +604,8 @@ extension DropboxFileProvider: ExtendedFileProvider {
         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")
+        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
@@ -567,7 +615,7 @@ extension DropboxFileProvider: ExtendedFileProvider {
             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] {
+                if let json = data?.deserializeJSON(), let properties = (json["media_info"] as? [String: Any])?["metadata"] as? [String: Any] {
                     (dic, keys) = self.mapMediaInfo(properties)
                 }
             }
@@ -577,14 +625,4 @@ extension DropboxFileProvider: ExtendedFileProvider {
     }
 }
 
-extension DropboxFileProvider: FileProvider {
-    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
-    }
-}
+extension DropboxFileProvider: FileProvider { }

Sources/DropboxHelper.swift

@@ -17,22 +17,18 @@ public struct FileProviderDropboxError: FileProviderHTTPError {
 
 /// Containts path, url and attributes of a Dropbox file or resource.
 public final class DropboxFileObject: FileObject {
-    internal init(name: String, path: String) {
-        super.init(url: URL(string: path) ?? URL(string: "/")!, name: name, path: path)
-    }
-    
     internal convenience init? (jsonStr: String) {
         guard let json = jsonStr.deserializeJSON() else { return nil }
         self.init(json: json)
     }
     
-    internal convenience init? (json: [String: AnyObject]) {
+    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 }
-        self.init(name: name, path: path)
+        super.init(url: nil, name: name, path: path)
         self.size = (json["size"] as? NSNumber)?.int64Value ?? -1
-        self.serverTime = resolve(dateString: json["server_modified"] as? String ?? "")
-        self.modifiedDate = resolve(dateString: json["client_modified"] as? String ?? "")
+        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
@@ -42,10 +38,10 @@ public final class DropboxFileObject: FileObject {
     /// The time contents of file has been modified on server, returns nil if not set
     open internal(set) var serverTime: Date? {
         get {
-            return allValues[.serverDate] as? Date
+            return allValues[.serverDateKey] as? Date
         }
         set {
-            allValues[.serverDate] = newValue
+            allValues[.serverDateKey] = newValue
         }
     }
     
@@ -88,8 +84,8 @@ internal extension DropboxFileProvider {
         }
         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)
         request.httpBody = Data(jsonDictionary: requestDictionary)
         let task = (session ?? self.session).dataTask(with: request, completionHandler: { (data, response, error) in
             var responseError: FileProviderDropboxError?
@@ -121,40 +117,8 @@ internal extension DropboxFileProvider {
         task.resume()
     }
     
-    func upload_simple(_ targetPath: String, data: Data, modifiedDate: Date = Date(), overwrite: Bool, operation: FileOperationType, completionHandler: SimpleCompletionHandler) -> OperationHandle? {
-        if data.count > 150 * 1024 * 1024 {
-            let error = FileProviderDropboxError(code: .payloadTooLarge, path: targetPath, errorDescription: nil)
-            completionHandler?(error)
-            self.delegateNotify(.create(path: targetPath), error: error)
-            return nil
-        }
-        var requestDictionary = [String: AnyObject]()
-        let url: URL
-        url = URL(string: "files/upload", relativeTo: contentURL)!
-        requestDictionary["path"] = correctPath(targetPath) as NSString?
-        requestDictionary["mode"] = (overwrite ? "overwrite" : "add") as NSString
-        requestDictionary["client_modified"] = rfc3339utc(of: 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(String(jsonDictionary: 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))
-            }
-            completionHandler?(responseError ?? error)
-            self.delegateNotify(.create(path: targetPath), error: responseError ?? error)
-        })
-        task.taskDescription = operation.json
-        task.resume()
-        return RemoteOperationHandle(operationType: operation, tasks: [task])
-    }
-    
-    func upload_simple(_ targetPath: String, localFile: URL, modifiedDate: Date = Date(), overwrite: Bool, operation: FileOperationType, completionHandler: SimpleCompletionHandler) -> OperationHandle? {
-        let size = (try? localFile.resourceValues(forKeys: [.fileSizeKey]))?.fileSize ?? -1
+    func upload_simple(_ targetPath: String, data: Data? = nil, localFile: URL? = nil, modifiedDate: Date = Date(), overwrite: Bool, operation: FileOperationType, completionHandler: SimpleCompletionHandler) -> OperationHandle? {
+        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)
@@ -166,20 +130,30 @@ internal extension DropboxFileProvider {
         url = URL(string: "files/upload", relativeTo: contentURL)!
         requestDictionary["path"] = correctPath(targetPath) as NSString?
         requestDictionary["mode"] = (overwrite ? "overwrite" : "add") as NSString
-        requestDictionary["client_modified"] = rfc3339utc(of: modifiedDate) as NSString
+        requestDictionary["client_modified"] = modifiedDate.rfc3339utc() 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(String(jsonDictionary: requestDictionary), forHTTPHeaderField: "Dropbox-API-Arg")
-        let task = session.uploadTask(with: request, fromFile: localFile, completionHandler: { (data, response, error) in
+        request.set(httpAuthentication: credential, with: .oAuth2)
+        request.set(contentType: .stream)
+        request.set(dropboxArgKey: requestDictionary)
+        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: 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))
+            if let code = (task.response as? HTTPURLResponse)?.statusCode , code >= 300, let rCode = FileProviderHTTPErrorCode(rawValue: code) {
+                // We can't fetch server result from delegate!
+                responseError = FileProviderDropboxError(code: rCode, path: targetPath, errorDescription: nil)
             }
             completionHandler?(responseError ?? error)
-            self.delegateNotify(.create(path: targetPath), error: responseError ?? error)
-        })
+            self?.delegateNotify(.create(path: targetPath), error: responseError ?? error)
+        }
         task.taskDescription = operation.json
         task.resume()
         return RemoteOperationHandle(operationType: operation, tasks: [task])
@@ -189,8 +163,8 @@ internal extension DropboxFileProvider {
         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
@@ -241,11 +215,11 @@ internal extension DropboxFileProvider {
             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))
+            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 = resolve(dateString: timeTakenStr) {
+        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)

Sources/ExtendedLocalFileProvider.swift

@@ -12,7 +12,7 @@ import CoreGraphics
 import AVFoundation
 
 extension LocalFileProvider: ExtendedFileProvider {
-    public func thumbnailOfFileSupported(path: String) -> Bool {
+    open func thumbnailOfFileSupported(path: String) -> Bool {
         switch (path as NSString).pathExtension.lowercased() {
         case LocalFileInformationGenerator.imageThumbnailExtensions:
             return true
@@ -31,7 +31,7 @@ extension LocalFileProvider: ExtendedFileProvider {
         }
     }
     
-    public func propertiesOfFileSupported(path: String) -> Bool {
+    open func propertiesOfFileSupported(path: String) -> Bool {
         let fileExt = (path as NSString).pathExtension.lowercased()
         switch fileExt {
         case LocalFileInformationGenerator.imagePropertiesExtensions:
@@ -54,7 +54,7 @@ extension LocalFileProvider: ExtendedFileProvider {
         }
     }
     
-    public func thumbnailOfFile(path: String, dimension: CGSize? = nil, completionHandler: @escaping ((_ image: ImageClass?, _ error: Error?) -> Void)) {
+    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
@@ -86,7 +86,7 @@ extension LocalFileProvider: ExtendedFileProvider {
         }
     }
     
-    public func propertiesOfFile(path: String, completionHandler: @escaping ((_ propertiesDictionary: [String: Any], _ keys: [String], _ error: Error?) -> Void)) {
+    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]))?
@@ -197,8 +197,13 @@ public struct LocalFileInformationGenerator {
     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 == AVMetadataCommonKeyArtwork {
+            if item.commonKey == commonKeyArtwork {
                 if let data = item.dataValue {
                     return ImageClass(data: data)
                 }
@@ -319,10 +324,10 @@ public struct LocalFileInformationGenerator {
             guard let key = key else {
                 return nil
             }
-            guard let regex = try? NSRegularExpression(pattern: "([a-z])([A-Z])" , options: NSRegularExpression.Options()) else {
+            guard let regex = try? NSRegularExpression(pattern: "([a-z])([A-Z])" , options: []) else {
                 return nil
             }
-            let newKey = regex.stringByReplacingMatches(in: key, options: NSRegularExpression.MatchingOptions(), range: NSMakeRange(0, (key as NSString).length) , withTemplate: "$1 $2")
+            let newKey = regex.stringByReplacingMatches(in: key, options: [], range: NSRange(location: 0, length: (key as NSString).length) , withTemplate: "$1 $2")
             return newKey.capitalized
         }
         
@@ -330,7 +335,12 @@ public struct LocalFileInformationGenerator {
             let playerItem = AVPlayerItem(url: fileURL)
             let metadataList = playerItem.asset.commonMetadata
             for item in metadataList {
-                if let description = makeDescription(item.commonKey) {
+                #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
@@ -366,7 +376,11 @@ public struct LocalFileInformationGenerator {
             }
         }
         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)
@@ -380,7 +394,11 @@ public struct LocalFileInformationGenerator {
             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 {
@@ -414,7 +432,7 @@ public struct LocalFileInformationGenerator {
             guard let date = date else { return nil }
             var dateStr = date
             if dateStr.hasPrefix("D:") {
-                dateStr = date.substring(from: date.characters.index(date.startIndex, offsetBy: 2))
+                dateStr.characters.removeFirst(2)
             }
             let dateFormatter = DateFormatter()
             dateFormatter.dateFormat = "yyyyMMddHHmmssTZD"

Sources/FPSStreamTask.swift

@@ -12,51 +12,107 @@ private var lasttaskIdAssociated = 1_000_000_000
 
 
 /// This class is a replica of NSURLSessionStreamTask with same api for iOS 7/8
-/// while it will fallback to NSURLSessionStreamTask in iOS 9.
-internal class FPSStreamTask: URLSessionTask, StreamDelegate {
+/// while it can actually fallback to NSURLSessionStreamTask in iOS 9.
+public class FileProviderStreamTask: URLSessionTask, StreamDelegate {
     fileprivate var inputStream: InputStream?
     fileprivate var outputStream: OutputStream?
     
-    fileprivate var dispatch_queue: DispatchQueue!
+    fileprivate var operation_queue: OperationQueue!
     internal var _underlyingSession: URLSession
     fileprivate var streamDelegate: FPSStreamDelegate? {
         return (_underlyingSession.delegate as? FPSStreamDelegate)
     }
     fileprivate var _taskIdentifier: Int
+    fileprivate var _taskDescription: String?
     
+    /// Force using `URLSessionStreamTask` for iOS 9 and later
+    public var useURLSession = true
     @available(iOS 9.0, OSX 10.11, *)
-    static var streamTasks = [Int: URLSessionStreamTask]()
+    fileprivate static var streamTasks = [Int: URLSessionStreamTask]()
     
     @available(iOS 9.0, OSX 10.11, *)
     internal var _underlyingTask: URLSessionStreamTask? {
-        return FPSStreamTask.streamTasks[_taskIdentifier]
+        return FileProviderStreamTask.streamTasks[_taskIdentifier]
     }
     
+    /**
+     * An identifier uniquely identifies the task within a given session.
+     *
+     * This value is unique only within the context of a single session; 
+     * tasks in other sessions may have the same `taskIdentifier` value.
+     */
     open override var taskIdentifier: Int {
         if #available(iOS 9.0, OSX 10.11, *) {
-            return _underlyingTask!.taskIdentifier
-        } else {
-            return _taskIdentifier
+            if self.useURLSession {
+                return _underlyingTask!.taskIdentifier
+            }
+        }
+        
+        return _taskIdentifier
+    }
+    
+    /// An app-provided description of the current task.
+    ///
+    /// This value may be nil. It is intended to contain human-readable strings that you can
+    /// then display to the user as part of your app’s user interface.
+    open override var taskDescription: String? {
+        get {
+            if #available(iOS 9.0, OSX 10.11, *) {
+                if self.useURLSession {
+                    return _underlyingTask!.taskDescription
+                }
+            }
+            
+            return _taskDescription
+        }
+        @objc(setTaskDescription:)
+        set {
+            if #available(iOS 9.0, OSX 10.11, *) {
+                if self.useURLSession {
+                    _underlyingTask!.taskDescription = newValue
+                    return
+                }
+            }
+            
+            _taskDescription = newValue
         }
     }
     
     fileprivate var _state: URLSessionTask.State = .suspended
+    /**
+     * The current state of the task—active, suspended, in the process 
+     * of being canceled, or completed.
+    */
     override open var state: URLSessionTask.State {
         if #available(iOS 9.0, OSX 10.11, *) {
-            return _underlyingTask!.state
-        } else {
-            return _state
+            if self.useURLSession {
+                return _underlyingTask!.state
+            }
         }
+        
+        return _state
     }
     
+    /**
+     * The original request object passed when the task was created.
+     * This value is typically the same as the currently active request (`currentRequest`)
+     * except when the server has responded to the initial request with a redirect to a different URL.
+    */
     override open var originalRequest: URLRequest? {
         if #available(iOS 9.0, OSX 10.11, *) {
-            return _underlyingTask!.originalRequest
-        } else {
-            return nil
+            if self.useURLSession {
+                return _underlyingTask!.originalRequest
+            }
         }
+        
+        return nil
     }
     
+    /**
+     * The URL request object currently being handled by the task.
+     * This value is typically the same as the initial request (`originalRequest`)
+     * except when the server has responded to the initial request with a redirect to a different URL.
+    */
     override open var currentRequest: URLRequest? {
         if #available(iOS 9.0, OSX 10.11, *) {
             return _underlyingTask!.currentRequest
@@ -68,398 +124,505 @@ internal class FPSStreamTask: URLSessionTask, StreamDelegate {
     fileprivate var _countOfBytesSent: Int64 = 0
     fileprivate var _countOfBytesRecieved: Int64 = 0
     
+    /**
+     * The number of bytes that the task has sent to the server in the request body.
+     *
+     * This byte count includes only the length of the request body itself, not the request headers.
+     *
+     * To be notified when this value changes, implement the 
+     * `urlSession(_:task:didSendBodyData:totalBytesSent:totalBytesExpectedToSend:)` delegate method.
+    */
     override open var countOfBytesSent: Int64 {
         if #available(iOS 9.0, OSX 10.11, *) {
-            return _underlyingTask!.countOfBytesSent
-        } else {
-            return _countOfBytesSent
+            if self.useURLSession {
+                return _underlyingTask!.countOfBytesSent
+            }
         }
+        
+        return _countOfBytesSent
     }
     
+    /**
+     * The number of bytes that the task has received from the server in the response body.
+     *
+     * To be notified when this value changes, implement the `urlSession(_:dataTask:didReceive:)` delegate method (for data and upload tasks)
+     * or the `urlSession(_:downloadTask:didWriteData:totalBytesWritten:totalBytesExpectedToWrite:)` method (for download tasks).
+    */
     override open var countOfBytesReceived: Int64 {
         if #available(iOS 9.0, OSX 10.11, *) {
-            return _underlyingTask!.countOfBytesReceived
-        } else {
-            return _countOfBytesRecieved
+            if self.useURLSession {
+                return _underlyingTask!.countOfBytesReceived
+            }
         }
+        
+        return _countOfBytesRecieved
     }
     
+    /**
+     * The number of bytes that the task expects to send in the request body.
+     *
+     * The `URL` loading system can determine the length of the upload data in three ways:
+     * - From the length of the `NSData` object provided as the upload body.
+     * - From the length of the file on disk provided as the upload body of an upload task (not a download task).
+     * - From the `Content-Length` in the request object, if you explicitly set it.
+     *
+     * Otherwise, the value is `NSURLSessionTransferSizeUnknown` (`-1`) if you provided a stream or body data object, or zero (`0`) if you did not.
+    */
     override open var countOfBytesExpectedToSend: Int64 {
         if #available(iOS 9.0, OSX 10.11, *) {
             return _underlyingTask!.countOfBytesExpectedToSend
         } else {
-            return Int64(dataToBeSent.length)
+            return Int64(dataToBeSent.count)
         }
     }
     
+    /**
+     * The number of bytes that the task expects to receive in the response body.
+     *
+     * This value is determined based on the `Content-Length` header received from the server.
+     * If that header is absent, the value is `NSURLSessionTransferSizeUnknown`.
+    */
     override open var countOfBytesExpectedToReceive: Int64 {
         if #available(iOS 9.0, OSX 10.11, *) {
-            return _underlyingTask!.countOfBytesExpectedToReceive
-        } else {
-            return Int64(dataReceived.length)
+            if self.useURLSession {
+                return _underlyingTask!.countOfBytesExpectedToReceive
+            }
         }
+        
+        return Int64(dataReceived.count)
     }
     
     override public init() {
         fatalError("Use NSURLSession.fpstreamTask() method")
     }
     
-    var host: (hostname: String, port: Int)?
-    var service: NetService?
+    fileprivate var host: (hostname: String, port: Int)?
+    fileprivate var service: NetService?
     
     internal init(session: URLSession, host: String, port: Int) {
         self._underlyingSession = session
         if #available(iOS 9.0, OSX 10.11, *) {
-            let task = session.streamTask(withHostName: host, port: port)
-            self._taskIdentifier = task.taskIdentifier
-            FPSStreamTask.streamTasks[_taskIdentifier] = task
-        } else {
-            lasttaskIdAssociated += 1
-            self._taskIdentifier = lasttaskIdAssociated
-            self.host = (host, port)
-            self.dispatch_queue = DispatchQueue(label: "FSPStreamTask", attributes: DispatchQueue.Attributes.concurrent)
+            if self.useURLSession {
+                let task = session.streamTask(withHostName: host, port: port)
+                self._taskIdentifier = task.taskIdentifier
+                FileProviderStreamTask.streamTasks[_taskIdentifier] = task
+                return
+            }
         }
+        
+        lasttaskIdAssociated += 1
+        self._taskIdentifier = lasttaskIdAssociated
+        self.host = (host, port)
+        self.operation_queue = OperationQueue()
+        self.operation_queue.name = "FileProviderStreamTask"
+        self.operation_queue.maxConcurrentOperationCount = 1
     }
     
     internal init(session: URLSession, netService: NetService) {
         self._underlyingSession = session
         if #available(iOS 9.0, OSX 10.11, *) {
-            let task = session.streamTask(with: netService)
-            self._taskIdentifier = task.taskIdentifier
-            FPSStreamTask.streamTasks[_taskIdentifier] = task
-        } else {
-            lasttaskIdAssociated += 1
-            self._taskIdentifier = lasttaskIdAssociated
-            self.service = netService
-            self.dispatch_queue = DispatchQueue(label: "FSPStreamTask", attributes: DispatchQueue.Attributes.concurrent)
+            if self.useURLSession {
+                let task = session.streamTask(with: netService)
+                self._taskIdentifier = task.taskIdentifier
+                FileProviderStreamTask.streamTasks[_taskIdentifier] = task
+                return
+            }
         }
+        
+        lasttaskIdAssociated += 1
+        self._taskIdentifier = lasttaskIdAssociated
+        self.service = netService
+        self.operation_queue = OperationQueue()
+        self.operation_queue.name = "FileProviderStreamTask"
+        self.operation_queue.maxConcurrentOperationCount = 1
     }
     
+    /**
+     * Cancels the task.
+     *
+     * This method returns immediately, marking the task as being canceled. Once a task is marked as being canceled, 
+     * `urlSession(_:task:didCompleteWithError:)` will be sent to the task delegate, passing an error
+     * in the domain NSURLErrorDomain with the code `NSURLErrorCancelled`. A task may, under some circumstances,
+     * send messages to its delegate before the cancelation is acknowledged.
+     *
+     * This method may be called on a task that is suspended.
+    */
     override open func cancel() {
         if #available(iOS 9.0, OSX 10.11, *) {
-            _underlyingTask!.cancel()
-        } else {
-            self._state = .canceling
-            inputStream?.setValue(kCFBooleanTrue, forKey: kCFStreamPropertyShouldCloseNativeSocket as String)
-            outputStream?.setValue(kCFBooleanTrue, forKey: kCFStreamPropertyShouldCloseNativeSocket as String)
-            
-            self.inputStream?.close()
-            self.outputStream?.close()
-            
-            self.inputStream?.remove(from: RunLoop.current, forMode: RunLoopMode.defaultRunLoopMode)
-            self.outputStream?.remove(from: RunLoop.current, forMode: RunLoopMode.defaultRunLoopMode)
-            
-            self.inputStream?.delegate = nil
-            self.outputStream?.delegate = nil
-            
-            self.inputStream = nil
-            self.outputStream = nil
-            
-            self._state = .completed
-            self._countOfBytesSent = 0
-            self._countOfBytesRecieved = 0
+            if self.useURLSession {
+                _underlyingTask!.cancel()
+                return
+            }
         }
+        
+        self._state = .canceling
+        inputStream?.setValue(kCFBooleanTrue, forKey: kCFStreamPropertyShouldCloseNativeSocket as String)
+        outputStream?.setValue(kCFBooleanTrue, forKey: kCFStreamPropertyShouldCloseNativeSocket as String)
+        
+        self.inputStream?.close()
+        self.outputStream?.close()
+        
+        self.inputStream?.remove(from: RunLoop.main, forMode: .defaultRunLoopMode)
+        self.outputStream?.remove(from: RunLoop.main, forMode: .defaultRunLoopMode)
+        
+        self.inputStream?.delegate = nil
+        self.outputStream?.delegate = nil
+        
+        self.inputStream = nil
+        self.outputStream = nil
+        
+        self._state = .completed
+        self._countOfBytesSent = 0
+        self._countOfBytesRecieved = 0
     }
     
     var _error: Error? = nil
+    
+    /**
+     * An error object that indicates why the task failed.
+     *
+     * This value is `NULL` if the task is still active or if the transfer completed successfully.
+    */
     override open var error: Error? {
         if #available(iOS 9.0, OSX 10.11, *) {
-            return _underlyingTask!.error
-        } else {
-            return _error
+            if useURLSession {
+                return _underlyingTask!.error
+            }
         }
+        
+        return _error
     }
     
+    /**
+     * Temporarily suspends a task.
+     *
+     * A task, while suspended, produces no network traffic and is not subject to timeouts. 
+     * A download task can continue transferring data at a later time. 
+     * All other tasks must start over when resumed.
+    */
     override open func suspend() {
         if #available(iOS 9.0, OSX 10.11, *) {
-            _underlyingTask!.suspend()
-        } else {
-            self._state = .suspended
+            if self.useURLSession {
+                _underlyingTask!.suspend()
+                return
+            }
         }
+        
+        self._state = .suspended
+        self.operation_queue.isSuspended = true
     }
     
+    // Resumes the task, if it is suspended.
     override open func resume() {
         if #available(iOS 9.0, OSX 10.11, *) {
-            _underlyingTask!.resume()
-        } else {
-            var readStream : Unmanaged<CFReadStream>?
-            var writeStream : Unmanaged<CFWriteStream>?
-            
-            if inputStream == nil || outputStream == nil {
-                if let host = host {
-                    let hostRef: CFString = NSString(string: host.hostname)
-                    CFStreamCreatePairWithSocketToHost(kCFAllocatorDefault, hostRef, UInt32(host.port), &readStream, &writeStream)
-                } else if let service = service {
-                    let cfnetService = CFNetServiceCreate(kCFAllocatorDefault, service.domain as CFString, service.type as CFString, service.name as CFString, Int32(service.port))
-                    CFStreamCreatePairWithSocketToNetService(kCFAllocatorDefault, cfnetService.takeRetainedValue(), &readStream, &writeStream)
-                }
-                
-                inputStream = readStream?.takeRetainedValue()
-                outputStream = writeStream?.takeRetainedValue()
-                guard let inputStream = inputStream, let outputStream = outputStream else {
-                    return
-                }
-                streamDelegate?.urlSession?(self._underlyingSession, streamTask: self, didBecome: inputStream, outputStream: outputStream)
+            if self.useURLSession {
+                _underlyingTask!.resume()
+                return
+            }
+        }
+        
+        var readStream : Unmanaged<CFReadStream>?
+        var writeStream : Unmanaged<CFWriteStream>?
+        
+        if inputStream == nil || outputStream == nil {
+            if let host = host {
+                CFStreamCreatePairWithSocketToHost(kCFAllocatorDefault, host.hostname as CFString, UInt32(host.port), &readStream, &writeStream)
+            } else if let service = service {
+                let cfnetService = CFNetServiceCreate(kCFAllocatorDefault, service.domain as CFString, service.type as CFString, service.name as CFString, Int32(service.port))
+                CFStreamCreatePairWithSocketToNetService(kCFAllocatorDefault, cfnetService.takeRetainedValue(), &readStream, &writeStream)
             }
             
+            inputStream = readStream?.takeRetainedValue()
+            outputStream = writeStream?.takeRetainedValue()
             guard let inputStream = inputStream, let outputStream = outputStream else {
                 return
             }
-            
-            inputStream.delegate = self
-            outputStream.delegate = self
-            
-            dispatch_queue.sync(execute: { 
-                inputStream.schedule(in: RunLoop.current, forMode: RunLoopMode.defaultRunLoopMode)
-                outputStream.schedule(in: RunLoop.current, forMode: RunLoopMode.defaultRunLoopMode)
-            })
-            
-            inputStream.open()
-            outputStream.open()
-            
-            _state = .running
+            streamDelegate?.urlSession?(self._underlyingSession, streamTask: self, didBecome: inputStream, outputStream: outputStream)
         }
-    }
-    
-    fileprivate let dataToBeSent: NSMutableData = NSMutableData()
-    fileprivate let dataReceived: NSMutableData = NSMutableData()
-    
-    /* Read minBytes, or at most maxBytes bytes and invoke the completion
-     * handler on the sessions delegate queue with the data or an error.
-     * If an error occurs, any outstanding reads will also fail, and new
-     * read requests will error out immediately.
-     */
-    open func readData(OfMinLength minBytes: Int, maxLength maxBytes: Int, timeout: TimeInterval, completionHandler: @escaping (Data?, Bool, NSError?) -> Void) {
-        if #available(iOS 9.0, OSX 10.11, *) {
-            _underlyingTask!.readData(ofMinLength: minBytes, maxLength: maxBytes, timeout: timeout, completionHandler: completionHandler as! (Data?, Bool, Error?) -> Void)
-        } else {
-            guard let inputStream = inputStream else {
-                return
-            }
-            var timedOut: Bool = false
-            dispatch_queue.async {
-                if timeout > 0 {
-                    self.dispatch_queue.asyncAfter(deadline: .now() + 1) {
-                        timedOut = true
-                        completionHandler(nil, inputStream.streamStatus == .atEnd, inputStream.streamError as NSError?)
-                    }
-                }
-                while (self.dataReceived.length == 0 || self.dataReceived.length < minBytes) && !timedOut {
-                    RunLoop.current.run(until: Date(timeIntervalSinceNow: 0.1));
-                    Thread.sleep(forTimeInterval: 0.1)
-                }
-                let dR = NSMutableData()
-                if self.dataReceived.length > maxBytes {
-                    let range = NSRange(location: 0, length: maxBytes - 1)
-                    dR.append(self.dataReceived.subdata(with: range))
-                    self.dataReceived.replaceBytes(in: range, withBytes: nil, length: 0)
-                } else {
-                    dR.append(self.dataReceived as Data)
-                    self.dataReceived.length = 0
-                }
-                completionHandler(dR as Data, inputStream.streamStatus == .atEnd, inputStream.streamError as NSError?)
-            }
-        }
-    }
-    
-    /* Write the data completely to the underlying socket.  If all the
-     * bytes have not been written by the timeout, a timeout error will
-     * occur.  Note that invocation of the completion handler does not
-     * guarantee that the remote side has received all the bytes, only
-     * that they have been written to the kernel. */
-    open func writeData(_ data: Data, timeout: TimeInterval, completionHandler: @escaping (Error?) -> Void) {
-        if #available(iOS 9.0, OSX 10.11, *) {
-            _underlyingTask!.write(data, timeout: timeout, completionHandler: completionHandler)
-        } else {
-            guard let outputStream = outputStream else {
-                return
-            }
-            var timedOut: Bool = false
-            dispatch_queue.async {
-                if timeout > 0 {
-                    self.dispatch_queue.asyncAfter(deadline: .now() + 1) {
-                        timedOut = true
-                        completionHandler(self._error)
-                    }
-                }
-                
-                self.dataToBeSent.append(data)
-                while !outputStream.hasSpaceAvailable && !timedOut {
-                    RunLoop.current.run(until: Date(timeIntervalSinceNow: 0.1));
-                    Thread.sleep(forTimeInterval: 0.1)
-                }
-                if self.dataToBeSent.length > 0 {
-                    let bytesWritten = outputStream.write(self.dataToBeSent.bytes.bindMemory(to: UInt8.self, capacity: self.dataToBeSent.length), maxLength: self.dataToBeSent.length) 
-                    if bytesWritten > 0 {
-                        let range = NSRange(location: 0, length: bytesWritten)
-                        self.dataToBeSent.replaceBytes(in: range, withBytes: nil, length: 0)
-                        self._countOfBytesSent += bytesWritten
-                        completionHandler(nil)
-                    } else {
-                        self._error = outputStream.streamError
-                        completionHandler(outputStream.streamError)
-                    }
-                }
-            }
-        }
-    }
-    
-    /* -captureStreams completes any already enqueued reads
-     * and writes, and then invokes the
-     * URLSession:streamTask:didBecomeInputStream:outputStream: delegate
-     * message. When that message is received, the task object is
-     * considered completed and will not receive any more delegate
-     * messages. */
-    open func captureStreams() {
-        if #available(iOS 9.0, OSX 10.11, *) {
-            _underlyingTask!.captureStreams()
-        } else {
-            guard let outputStream = outputStream, let inputStream = inputStream else {
-                return
-            }
-            dispatch_queue.async {
-                self.write(false)
-                while inputStream.streamStatus != .atEnd {
-                    RunLoop.current.run(until: Date(timeIntervalSinceNow: 0.1));
-                    Thread.sleep(forTimeInterval: 0.1)
-                }
-                self.streamDelegate?.urlSession?(self._underlyingSession, streamTask: self, didBecome: inputStream, outputStream: outputStream)
-            }
-        }
-    }
-    
-    /* Enqueue a request to close the write end of the underlying socket.
-     * All outstanding IO will complete before the write side of the
-     * socket is closed.  The server, however, may continue to write bytes
-     * back to the client, so best practice is to continue reading from
-     * the server until you receive EOF.
-     */
-    open func closeWrite() {
-        if #available(iOS 9.0, OSX 10.11, *) {
-            _underlyingTask!.closeWrite()
-        } else {
-            dispatch_queue.async(execute: { 
-                self.write(true)
-            })
-        }
-    }
-    
-    fileprivate func write(_ close: Bool) {
-        guard let outputStream = outputStream else {
+        
+        guard let inputStream = inputStream, let outputStream = outputStream else {
             return
         }
-        while self.dataToBeSent.length > 0 {
-            let bytesWritten = outputStream.write(self.dataToBeSent.bytes.bindMemory(to: UInt8.self, capacity: self.dataToBeSent.length), maxLength: self.dataToBeSent.length) 
-            if bytesWritten > 0 {
-                let range = NSRange(location: 0, length: bytesWritten)
-                self.dataToBeSent.replaceBytes(in: range, withBytes: nil, length: 0)
-                self._countOfBytesSent += bytesWritten
-            } else {
-                self._error = outputStream.streamError as NSError?
+        
+        inputStream.delegate = self
+        outputStream.delegate = self
+        
+        operation_queue.addOperation {
+            inputStream.schedule(in: RunLoop.main, forMode: .defaultRunLoopMode)
+            outputStream.schedule(in: RunLoop.main, forMode: .defaultRunLoopMode)
+        }
+        
+        inputStream.open()
+        outputStream.open()
+        
+        operation_queue.isSuspended = false
+        _state = .running
+    }
+    
+    fileprivate var dataToBeSent: Data = Data()
+    fileprivate var dataReceived: Data = Data()
+    
+    /**
+     * Asynchronously reads a number of bytes from the stream, and calls a handler upon completion.
+     *
+     * - Parameter minBytes: The minimum number of bytes to read.
+     * - ParametermaxBytes: The maximum number of bytes to read.
+     * - Parameter timeout:  A timeout for reading bytes. If the read is not completed within the specified interval,
+     *        the read is canceled and the completionHandler is called with an error. Pass `0` to prevent a read from timing out.
+     * - Parameter completionHandler: The completion handler to call when all bytes are read, or an error occurs.
+     *        This handler is executed on the delegate queue. This completion handler takes the following parameters:
+     *     - data: The data read from the stream.
+     *     - atEOF: Whether or not the stream reached end-of-file (`EOF`), such that no more data can be read.
+     *     - error: An error object that indicates why the read failed, or `nil` if the read was successful.
+    */
+    open func readData(ofMinLength minBytes: Int, maxLength maxBytes: Int, timeout: TimeInterval, completionHandler: @escaping (_ data: Data?, _ atEOF: Bool, _ error :Error?) -> Void) {
+        if #available(iOS 9.0, OSX 10.11, *) {
+            if self.useURLSession {
+                _underlyingTask!.readData(ofMinLength: minBytes, maxLength: maxBytes, timeout: timeout, completionHandler: completionHandler)
+                return
             }
-            if self.dataToBeSent.length == 0 {
+        }
+        
+        guard let inputStream = inputStream else {
+            return
+        }
+        
+        let expireDate = Date(timeIntervalSinceNow: timeout)
+        operation_queue.addOperation {
+            var timedOut: Bool = false
+            while (self.dataReceived.count == 0 || self.dataReceived.count < minBytes) && !timedOut {
+                Thread.sleep(forTimeInterval: 0.1)
+                timedOut = expireDate < Date()
+            }
+            var dR: Data?
+            if self.dataReceived.count > maxBytes {
+                let range: Range = 0..<maxBytes
+                dR = self.dataReceived.subdata(in: range)
+                self.dataReceived.replaceSubrange(range, with: Data())
+            } else {
+                if self.dataReceived.count > 0 {
+                    dR = self.dataReceived
+                    self.dataReceived.count = 0
+                }
+            }
+            let isEOF = inputStream.streamStatus == .atEnd && self.dataReceived.count == 0
+            completionHandler(dR, isEOF, dR == nil ? inputStream.streamError : nil)
+        }
+    }
+    
+    /**
+     * Asynchronously writes the specified data to the stream, and calls a handler upon completion.
+     *
+     * There is no guarantee that the remote side of the stream has received all of the written bytes
+     * at the time that `completionHandler` is called, only that all of the data has been written to the kernel.
+     *
+     * - Parameter data: The data to be written.
+     * - Parameter timeout: A timeout for writing bytes. If the write is not completed within the specified interval,
+     *      the write is canceled and the `completionHandler` is called with an error.
+     *      Pass `0` to prevent a write from timing out.
+     * - Parameter completionHandler: The completion handler to call when all bytes are written, or an error occurs.
+     *      This handler is executed on the delegate queue.
+     *      This completion handler takes the following parameter:
+     *      - error: An error object that indicates why the write failed, or nil if the write was successful.
+    */
+    open func write(_ data: Data, timeout: TimeInterval, completionHandler: @escaping (_ error: Error?) -> Void) {
+        if #available(iOS 9.0, OSX 10.11, *) {
+            if self.useURLSession {
+                _underlyingTask!.write(data, timeout: timeout, completionHandler: completionHandler)
+                return
+            }
+        }
+        
+        guard outputStream != nil else {
+            return
+        }
+        
+        
+        operation_queue.addOperation {
+            self.dataToBeSent.append(data)
+            let result = self.write(timeout: timeout, close: false)
+            if result < 0 {
+                let error = self.outputStream?.streamError ?? NSError(domain: URLError.errorDomain, code: URLError.cannotWriteToFile.rawValue, userInfo: nil)
+                completionHandler(error)
+            } else {
+                completionHandler(nil)
+            }
+        }
+    }
+    
+    /**
+     * Completes any already enqueued reads and writes, and then invokes the 
+     * `urlSession(_:streamTask:didBecome:outputStream:)` delegate message.
+    */
+    open func captureStreams() {
+        if #available(iOS 9.0, OSX 10.11, *) {
+            if self.useURLSession {
+                _underlyingTask!.captureStreams()
+                return
+            }
+        }
+        
+        guard let outputStream = outputStream, let inputStream = inputStream else {
+            return
+        }
+        self.operation_queue.addOperation {
+            _=self.write(close: false)
+            while inputStream.streamStatus != .atEnd || outputStream.streamStatus == .writing {
+                Thread.sleep(forTimeInterval: 0.1)
+            }
+            self.streamDelegate?.urlSession?(self._underlyingSession, streamTask: self, didBecome: inputStream, outputStream: outputStream)
+        }
+    }
+    
+    /**
+     * Completes any enqueued reads and writes, and then closes the write side of the underlying socket.
+     *
+     * You may continue to read data using the `readData(ofMinLength:maxLength:timeout:completionHandler:)`
+     * method after calling this method. Any calls to `write(_:timeout:completionHandler:)` after calling 
+     * this method will result in an error.
+     *
+     * Because the server may continue to write bytes to the client, it is recommended that 
+     * you continue reading until the stream reaches end-of-file (EOF).
+    */
+    open func closeWrite() {
+        if #available(iOS 9.0, OSX 10.11, *) {
+            if self.useURLSession {
+                _underlyingTask!.closeWrite()
+                return
+            }
+        }
+        
+        operation_queue.addOperation {
+            _ = self.write(close: true)
+        }
+    }
+    
+    fileprivate func write(timeout: TimeInterval = 0, close: Bool) -> Int {
+        guard let outputStream = outputStream else {
+            return -1
+        }
+        
+        var byteSent: Int = 0
+        let expireDate = Date(timeIntervalSinceNow: timeout)
+        while self.dataToBeSent.count > 0 && (timeout == 0 || expireDate > Date()) {
+            let bytesWritten = self.dataToBeSent.withUnsafeBytes {
+                outputStream.write($0, maxLength: self.dataToBeSent.count)
+            }
+            
+            if bytesWritten > 0 {
+                let range = 0..<bytesWritten
+                self.dataToBeSent.replaceSubrange(range, with: Data())
+                byteSent += bytesWritten
+            } else if bytesWritten < 0 {
+                self._error = outputStream.streamError
+                return bytesWritten
+            }
+            if self.dataToBeSent.count == 0 {
                 break
             }
-            RunLoop.current.run(until: Date(timeIntervalSinceNow: 0.1));
-            Thread.sleep(forTimeInterval: 0.1)
         }
+        self._countOfBytesSent += Int64(byteSent)
         if close {
             outputStream.close()
             self.streamDelegate?.urlSession?(self._underlyingSession, writeClosedFor: self)
         }
+        return byteSent
     }
     
-    /* Enqueue a request to close the read side of the underlying socket.
-     * All outstanding IO will complete before the read side is closed.
-     * You may continue writing to the server.
-     */
+    /**
+     * Completes any enqueued reads and writes, and then closes the read side of the underlying socket.
+     *
+     * You may continue to write data using the `write(_:timeout:completionHandler:)` method after 
+     * calling this method. Any calls to `readData(ofMinLength:maxLength:timeout:completionHandler:)`
+     * after calling this method will result in an error.
+    */
     open func closeRead() {
         if #available(iOS 9.0, OSX 10.11, *) {
-            _underlyingTask!.closeRead()
-        } else {
-            guard let inputStream = inputStream else {
+            if self.useURLSession {
+                _underlyingTask!.closeRead()
                 return
             }
-            dispatch_queue.async {
-                while inputStream.streamStatus != .atEnd {
-                    RunLoop.current.run(until: Date(timeIntervalSinceNow: 0.1));
-                    Thread.sleep(forTimeInterval: 0.1)
-                }
-                inputStream.close()
-                self.streamDelegate?.urlSession?(self._underlyingSession, readClosedFor: self)
+        }
+        
+        guard let inputStream = inputStream else {
+            return
+        }
+        operation_queue.addOperation {
+            while inputStream.streamStatus != .atEnd {
+                Thread.sleep(forTimeInterval: 0.1)
             }
+            inputStream.close()
+            self.streamDelegate?.urlSession?(self._underlyingSession, readClosedFor: self)
         }
     }
     
-    /*
-     * Begin encrypted handshake.  The hanshake begins after all pending
-     * IO has completed.  TLS authentication callbacks are sent to the
-     * session's -URLSession:task:didReceiveChallenge:completionHandler:
-     */
+    /**
+     * Completes any enqueued reads and writes, and establishes a secure connection.
+     *
+     * Authentication callbacks are sent to the session's delegate using the
+     * `urlSession(_:task:didReceive:completionHandler:)` method.
+    */
     open func startSecureConnection() {
         if #available(iOS 9.0, OSX 10.11, *) {
-            _underlyingTask!.startSecureConnection()
-        } else {
-            inputStream!.setProperty(StreamSocketSecurityLevel.negotiatedSSL.rawValue, forKey: .socketSecurityLevelKey)
-            outputStream!.setProperty(StreamSocketSecurityLevel.negotiatedSSL.rawValue, forKey: .socketSecurityLevelKey)
+            if self.useURLSession {
+                _underlyingTask!.startSecureConnection()
+                return
+            }
+        }
+        
+        operation_queue.addOperation {
+            self.inputStream!.setProperty(StreamSocketSecurityLevel.negotiatedSSL.rawValue, forKey: .socketSecurityLevelKey)
+            self.outputStream!.setProperty(StreamSocketSecurityLevel.negotiatedSSL.rawValue, forKey: .socketSecurityLevelKey)
         }
     }
     
-    /*
-     * Cleanly close a secure connection after all pending secure IO has
-     * completed.
-     */
+    /**
+     * Completes any enqueued reads and writes, and closes the secure connection.
+    */
     open func stopSecureConnection() {
         if #available(iOS 9.0, OSX 10.11, *) {
-            _underlyingTask!.stopSecureConnection()
-        } else {
-            inputStream!.setProperty(StreamSocketSecurityLevel.none.rawValue, forKey: .socketSecurityLevelKey)
-            outputStream!.setProperty(StreamSocketSecurityLevel.none.rawValue, forKey: .socketSecurityLevelKey)
+            if self.useURLSession {
+                _underlyingTask!.stopSecureConnection()
+                return
+            }
+        }
+        operation_queue.addOperation {
+            self.inputStream!.setProperty(StreamSocketSecurityLevel.none.rawValue, forKey: .socketSecurityLevelKey)
+            self.outputStream!.setProperty(StreamSocketSecurityLevel.none.rawValue, forKey: .socketSecurityLevelKey)
         }
     }
     
     open func stream(_ aStream: Stream, handle eventCode: Stream.Event) {
-        switch (eventCode) {
-        case Stream.Event.errorOccurred:
-            self._error = aStream.streamError as NSError?
+        if eventCode.contains(.errorOccurred) {
+            self._error = aStream.streamError
             streamDelegate?.urlSession?(_underlyingSession, task: self, didCompleteWithError: error)
-        case Stream.Event.endEncountered:
-            break
-        case Stream.Event():
-            break
-        case Stream.Event.openCompleted:
-            break
-        case Stream.Event.hasBytesAvailable:
-            var buffer = [UInt8](repeating: 0, count: 2048)
-            if (aStream == inputStream) {
-                while (inputStream!.hasBytesAvailable) {
-                    let len = inputStream!.read(&buffer, maxLength: buffer.count)
-                    if len > 0 {
-                        dataReceived.append(&buffer, length: len)
-                        self._countOfBytesRecieved += len
-                    }
+        }
+        
+        if aStream == inputStream && eventCode.contains(.hasBytesAvailable) {
+            while (inputStream!.hasBytesAvailable) {
+                var buffer = [UInt8](repeating: 0, count: 2048)
+                let len = inputStream!.read(&buffer, maxLength: buffer.count)
+                if len > 0 {
+                    dataReceived.append(&buffer, count: len)
+                    self._countOfBytesRecieved += Int64(len)
                 }
             }
-        case Stream.Event.hasSpaceAvailable:
-            break
-        default:
-            break
         }
     }
 }
 
-internal extension URLSession {
-    /* Creates a bidirectional stream task to a given host and port.
-     */
-    func fpstreamTaskWithHostName(_ hostname: String, port: Int) -> FPSStreamTask {
-        return FPSStreamTask(session: self, host: hostname, port: port)
+public extension URLSession {
+    /// Creates a bidirectional stream task to a given host and port.
+    func fpstreamTask(withHostName hostname: String, port: Int) -> FileProviderStreamTask {
+        return FileProviderStreamTask(session: self, host: hostname, port: port)
     }
     
-    /* Creates a bidirectional stream task with an NSNetService to identify the endpoint.
+    /**
+     * Creates a bidirectional stream task with an NSNetService to identify the endpoint.
      * The NSNetService will be resolved before any IO completes.
-     */
-    func fpstreamTaskWithNetService(_ service: NetService) -> FPSStreamTask {
-        return fpstreamTaskWithNetService(service)
+    */
+    func fpstreamTask(withNetService service: NetService) -> FileProviderStreamTask {
+        return FileProviderStreamTask(session: self, netService: service)
     }
 }
 
@@ -467,42 +630,46 @@ internal extension URLSession {
 internal protocol FPSStreamDelegate : URLSessionTaskDelegate {
     
     
-    /* Indiciates that the read side of a connection has been closed.  Any
+    /**
+     * Indiciates that the read side of a connection has been closed.  Any
      * outstanding reads complete, but future reads will immediately fail.
      * This may be sent even when no reads are in progress. However, when
      * this delegate message is received, there may still be bytes
      * available.  You only know that no more bytes are available when you
      * are able to read until EOF. */
-    @objc optional func urlSession(_ session: URLSession, readClosedFor streamTask: FPSStreamTask)
+    @objc optional func urlSession(_ session: URLSession, readClosedFor streamTask: FileProviderStreamTask)
     
     
-    /* Indiciates that the write side of a connection has been closed.
+    /**
+     * Indiciates that the write side of a connection has been closed.
      * Any outstanding writes complete, but future writes will immediately
      * fail.
      */
-    @objc optional func urlSession(_ session: URLSession, writeClosedFor streamTask: FPSStreamTask)
+    @objc optional func urlSession(_ session: URLSession, writeClosedFor streamTask: FileProviderStreamTask)
     
     
-    /* A notification that the system has determined that a better route
+    /**
+     * A notification that the system has determined that a better route
      * to the host has been detected (eg, a wi-fi interface becoming
      * available.)  This is a hint to the delegate that it may be
      * desirable to create a new task for subsequent work.  Note that
      * there is no guarantee that the future task will be able to connect
      * to the host, so callers should should be prepared for failure of
      * reads and writes over any new interface. */
-    @objc optional func urlSession(_ session: URLSession, betterRouteDiscoveredFor streamTask: FPSStreamTask)
+    @objc optional func urlSession(_ session: URLSession, betterRouteDiscoveredFor streamTask: FileProviderStreamTask)
     
     
-    /* The given task has been completed, and unopened NSInputStream and
+    /**
+     * The given task has been completed, and unopened NSInputStream and
      * NSOutputStream objects are created from the underlying network
      * connection.  This will only be invoked after all enqueued IO has
      * completed (including any necessary handshakes.)  The streamTask
      * will not receive any further delegate messages.
      */
-    @objc optional func urlSession(_ session: URLSession, streamTask: FPSStreamTask, didBecome inputStream: InputStream, outputStream: OutputStream)
+    @objc optional func urlSession(_ session: URLSession, streamTask: FileProviderStreamTask, didBecome inputStream: InputStream, outputStream: OutputStream)
 }
 
-private let ports: [String: Int] = ["http": 80, "https": 443, "smb": 445,"ftp": 21,"ftps": 22, "sftp": 2121,
+private let ports: [String: Int] = ["http": 80, "https": 443, "smb": 445,"ftp": 21,
                                     "telnet": 23, "pop": 110, "smtp": 25, "imap": 143]
-private let securePorts: [String: Int] =  ["https": 443, "smb": 445, "ftps": 22, "sftp": 2121,
-                                           "telnet": 992, "pop": 995, "smtp": 465, "imap": 993]
+private let securePorts: [String: Int] =  ["ssh": 22, "https": 443, "smb": 445, "smtp": 465,
+                                            "ftps": 990,"telnet": 992, "imap": 993, "pop": 995]

Sources/FTPFileProvider.swift

@@ -0,0 +1,802 @@
+//
+//  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)!
+        urlComponents.port = urlComponents.port ?? 21
+        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)) {
+        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)
+                }
+            }
+        }, completionHandler: {files, error in
+            if let error = error {
+                completionHandler([], error)
+                return
+            }
+            
+            let foundFiles = files.filter { query.evaluate(with: $0.mapPredicate()) }
+            completionHandler(foundFiles, nil)
+        })
+    }
+    
+    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) -> OperationHandle? {
+        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) -> OperationHandle? {
+        return doOperation(.move(source: path, destination: toPath), completionHandler: completionHandler)
+    }
+    
+    open func copyItem(path: String, to toPath: String, overwrite: Bool, completionHandler: SimpleCompletionHandler) -> OperationHandle? {
+        return doOperation(.copy(source: path, destination: toPath), completionHandler: completionHandler)
+    }
+    
+    open func removeItem(path: String, completionHandler: SimpleCompletionHandler) -> OperationHandle? {
+        return doOperation(.remove(path: path), completionHandler: completionHandler)
+    }
+    
+    fileprivate func doOperation(_ opType: FileOperationType, completionHandler: SimpleCompletionHandler) -> OperationHandle? {
+        guard fileOperationDelegate?.fileProvider(self, shouldDoOperation: opType) ?? true == true else {
+            return nil
+        }
+        guard let sourcePath = opType.source else { return nil }
+        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 operationHandle = RemoteOperationHandle(operationType: opType, tasks: [])
+        
+        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:
+                        let opHandle = self.fallbackCopy(opType, completionHandler: completionHandler) as? RemoteOperationHandle
+                        operationHandle.tasks = opHandle?.tasks ?? []
+                        return
+                    case .move:
+                        errorCode = URLError.cannotMoveFile
+                    case .remove:
+                        self.fallbackRemove(opType, on: task, completionHandler: completionHandler)
+                        return
+                    case .link:
+                        errorCode = URLError.cannotWriteToFile
+                    default:
+                        errorCode = URLError.cannotOpenFile
+                    }
+                    let error = self.throwError(sourcePath, code: errorCode)
+                    self.dispatch_queue.async {
+                        completionHandler?(error)
+                        self.delegateNotify(opType, error: error)
+                    }
+                    return
+                }
+                
+                self.dispatch_queue.async {
+                    completionHandler?(nil)
+                    self.delegateNotify(opType, error: nil)
+                }
+            })
+        }
+        
+        operationHandle.add(task: task)
+        return operationHandle
+    }
+    
+    private func fallbackCopy(_ opType: FileOperationType, completionHandler: SimpleCompletionHandler) -> OperationHandle? {
+        guard let sourcePath = opType.source else { return nil }
+        guard let destPath = opType.destination else { return nil }
+        
+        let localURL = URL(fileURLWithPath: NSTemporaryDirectory()).appendingPathComponent(UUID().uuidString).appendingPathExtension("tmp")
+        let operationHandle = RemoteOperationHandle(operationType: opType, tasks: [])
+        let firstOp = self.copyItem(path: sourcePath, toLocalURL: localURL, completionHandler: { (error) in
+            if let error = error {
+                self.dispatch_queue.async {
+                    completionHandler?(error)
+                    self.delegateNotify(opType, error: error)
+                }
+                return
+            }
+            
+            let secondOp = self.copyItem(localFile: localURL, to: destPath, completionHandler: { error in
+                completionHandler?(nil)
+                self.delegateNotify(opType, error: nil)
+            }) as? RemoteOperationHandle
+            operationHandle.tasks = secondOp?.tasks ?? []
+        }) as? RemoteOperationHandle
+        operationHandle.tasks = firstOp?.tasks ?? []
+        return operationHandle
+    }
+    
+    private func fallbackRemove(_ opType: FileOperationType, on task: FileProviderStreamTask, completionHandler: SimpleCompletionHandler) {
+        guard let sourcePath = opType.source else { return }
+        
+        self.execute(command: "SITE RMDIR \(ftpPath(sourcePath))", on: task) { (response, error) in
+            if let error = error {
+                self.dispatch_queue.async {
+                    completionHandler?(error)
+                    self.delegateNotify(opType, error: error)
+                }
+                return
+            }
+            
+            guard let response = response else {
+                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, 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, on task: FileProviderStreamTask, completionHandler: SimpleCompletionHandler) {
+        guard let sourcePath = opType.source else { return }
+        
+        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 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
+                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) -> OperationHandle? {
+        // 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 operation = RemoteOperationHandle(operationType: opType, tasks: [])
+        
+        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: {
+                operation.add(task: $0)
+            }, onProgress: { bytesSent, totalSent, expectedBytes in
+                DispatchQueue.main.async {
+                    self.delegate?.fileproviderProgress(self, operation: opType, progress: Float(Double(totalSent) / Double(expectedBytes)))
+                }
+            }, completionHandler: { (error) in
+                self.ftpQuit(task)
+                self.dispatch_queue.async {
+                    completionHandler?(error)
+                    self.delegateNotify(opType, error: error)
+                }
+            })
+        }
+        
+        return operation
+    }
+    
+    open func copyItem(path: String, toLocalURL destURL: URL, completionHandler: SimpleCompletionHandler) -> OperationHandle? {
+        let opType = FileOperationType.copy(source: path, destination: destURL.absoluteString)
+        guard fileOperationDelegate?.fileProvider(self, shouldDoOperation: opType) ?? true == true else {
+            return nil
+        }
+        let operation = RemoteOperationHandle(operationType: opType, tasks: [])
+        
+        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
+                }
+                
+                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)
+                    }
+                }
+                operation.add(task: task)
+                task.taskDescription = opType.json
+                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: {
+                    operation.add(task: $0)
+                }, onProgress: { recevied, totalReceived, totalSize in
+                    let progress = Double(totalReceived) / Double(totalSize)
+                    self.delegate?.fileproviderProgress(self, operation: opType, progress: Float(progress))
+                }) { (tmpurl, error) in
+                    if let error = error {
+                        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 operation
+    }
+}
+
+extension FTPFileProvider: FileProviderReadWrite {
+    open func contents(path: String, completionHandler: @escaping ((Data?, Error?) -> Void)) -> OperationHandle? {
+        let opType = FileOperationType.fetch(path: path)
+        guard fileOperationDelegate?.fileProvider(self, shouldDoOperation: opType) ?? true == true else {
+            return nil
+        }
+        
+        if self.useAppleImplementation {
+            let task = session.downloadTask(with: url(of: path))
+            completionHandlersForTasks[session.sessionDescription!]?[task.taskIdentifier] = { error in
+                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.resume()
+            return RemoteOperationHandle(operationType: opType, tasks: [task])
+        } 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)) -> OperationHandle? {
+        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 operation = RemoteOperationHandle(operationType: opType, tasks: [])
+        
+        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: {
+                operation.add(task: $0)
+            }, onProgress: { recevied, totalReceived, totalSize in
+                let progress = Double(totalReceived) / Double(totalSize)
+                self.delegate?.fileproviderProgress(self, operation: opType, progress: Float(progress))
+            }) { (data, error) in
+                if let error = error {
+                    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 operation
+    }
+    
+    open func writeContents(path: String, contents data: Data?, atomically: Bool, overwrite: Bool, completionHandler: SimpleCompletionHandler) -> OperationHandle? {
+        let opType = FileOperationType.modify(path: path)
+        guard fileOperationDelegate?.fileProvider(self, shouldDoOperation: opType) ?? true == true else {
+            return nil
+        }
+        
+        let operation = RemoteOperationHandle(operationType: opType, tasks: [])
+        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: {
+                    operation.add(task: $0)
+                }, onProgress: { bytesSent, totalSent, expectedBytes in
+                    DispatchQueue.main.async {
+                        self.delegate?.fileproviderProgress(self, operation: opType, progress: Float(Double(totalSent) / Double(expectedBytes)))
+                    }
+                }, completionHandler: { (error) in
+                    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 operation
+    }
+}
+
+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 { }

Sources/FTPHelper.swift

@@ -0,0 +1,941 @@
+//
+//  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()
+        }
+        
+        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 = {
+                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 response.hasPrefix("33") {
+                        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 self.baseURL?.scheme == "ftps" || self.baseURL?.port == 990 {
+                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()
+                        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?.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) {
+        let queue = DispatchQueue(label: "test")
+        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)
+                foundItemsHandler?(files)
+                
+                let directories: [FileObject] = files.filter { $0.isDirectory }
+                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()
+                    })
+                }
+                group.leave()
+            })
+            group.wait()
+            
+            if success {
+                self.dispatch_queue.async {
+                    completionHandler(result, nil)
+                }
+            }
+        }
+    }
+    
+    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
+        }
+    }
+}

Sources/FileObject.swift

@@ -13,31 +13,32 @@ open class FileObject: Equatable {
     /// A `Dictionary` contains file information,  using `URLResourceKey` keys.
     open internal(set) var allValues: [URLResourceKey: Any]
     
-    internal init(allValues: [URLResourceKey: Any]) {
+    public init(allValues: [URLResourceKey: Any]) {
         self.allValues = allValues
     }
     
-    internal init(url: URL, name: String, path: String) {
+    internal init(url: URL?, name: String, path: String) {
         self.allValues = [URLResourceKey: Any]()
-        self.url = url
+        if let url = url {
+            self.url = url
+        }
         self.name = name
         self.path = path
     }
     
-    /// url to access the resource, not supported by Dropbox provider
-    @available(*, deprecated, renamed: "url", message: "Use url.absoluteURL instead.")
-    open var absoluteURL: URL? {
-        return url?.absoluteURL
-    }
-    
     /// URL to access the resource, can be a relative URL against base URL.
     /// not supported by Dropbox provider.
-    open internal(set) var url: URL? {
+    open internal(set) var url: URL {
         get {
-            return allValues[.fileURL] as? URL
+            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[.fileURL] = newValue
+            allValues[.fileURLKey] = newValue
         }
     }
     
@@ -139,21 +140,28 @@ open class FileObject: Equatable {
     
     /// Check `FileObject` equality
     public static func ==(lhs: FileObject, rhs: FileObject) -> Bool {
-        if rhs === lhs {
+        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
         }
-        if let rurl = rhs.url, let lurl = lhs.url {
+        #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] = [.fileURL: "url", .nameKey: "name", .pathKey: "path", .fileSizeKey: "filesize", .creationDateKey: "creationDate",
-                                                 .contentModificationDateKey: "modifiedDate", .isHiddenKey: "isHidden", .isWritableKey: "isWritable", .serverDate: "serverDate", .entryTag: "entryTag", .mimeType: "mimeType"]
+        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 {
@@ -170,10 +178,11 @@ open class FileObject: Equatable {
         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: .fileURL, NSMetadataItemFSNameKey: .nameKey, NSMetadataItemPathKey: .pathKey,
+        let mapDict: [String: URLResourceKey] = [NSMetadataItemURLKey: .fileURLKey, NSMetadataItemFSNameKey: .nameKey, NSMetadataItemPathKey: .pathKey,
                                                  NSMetadataItemFSSizeKey: .fileSizeKey, NSMetadataItemFSCreationDateKey: .creationDateKey,
-                                                 NSMetadataItemFSContentChangeDateKey: .contentModificationDateKey, "kMDItemFSInvisible": .isHiddenKey, "kMDItemFSIsWriteable": .isWritableKey, "kMDItemKind": .mimeType]
+                                                 NSMetadataItemFSContentChangeDateKey: .contentModificationDateKey, "kMDItemFSInvisible": .isHiddenKey, "kMDItemFSIsWriteable": .isWritableKey, "kMDItemKind": .mimeTypeKey]
         
         if let cQuery = query as? NSCompoundPredicate {
             let newSub = cQuery.subpredicates.map { convertPredicate(fromSpotlight: $0 as! NSPredicate) }
@@ -198,37 +207,6 @@ open class FileObject: Equatable {
     }
 }
 
-internal func resolve(dateString: String) -> Date? {
-    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: dateString) {
-        return rfc3339
-    }
-    dateFor.dateFormat = "EEE',' dd' 'MMM' 'yyyy HH':'mm':'ss z"
-    if let rfc1123 = dateFor.date(from: dateString) {
-        return rfc1123
-    }
-    dateFor.dateFormat = "EEEE',' dd'-'MMM'-'yy HH':'mm':'ss z"
-    if let rfc850 = dateFor.date(from: dateString) {
-        return rfc850
-    }
-    dateFor.dateFormat = "EEE MMM d HH':'mm':'ss yyyy"
-    if let asctime = dateFor.date(from: dateString) {
-        return asctime
-    }
-    
-    return nil
-}
-
-internal func rfc3339utc(of date:Date) -> 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:date)
-}
-
 /// Sorting FileObject array by given criteria, **not thread-safe**
 public struct FileObjectSorting {
     

Sources/FileProvider.swift

@@ -19,7 +19,7 @@ public typealias ImageClass = NSImage
 public typealias SimpleCompletionHandler = ((_ error: Error?) -> Void)?
 
 /// This protocol defines FileProvider neccesary functions and properties to connect and get contents list
-public protocol FileProviderBasic: class {
+public protocol FileProviderBasic: class, NSSecureCoding {
     /// An string to identify type of provider.
     static var type: String { get }
     
@@ -51,13 +51,13 @@ public protocol FileProviderBasic: class {
      
      **Example initialization:**
      ````
-     let credential = URLCredential(user: "user", password: "password", persistence: .forSeession)
+     provider.credential = URLCredential(user: "user", password: "password", persistence: .forSeession)
      ````
      
      - Note: In OAuth based providers like `DropboxFileProvider` and `OneDriveFileProvider`, password is Token.
      use [OAuthSwift](https://github.com/OAuthSwift/OAuthSwift) library to fetch clientId and Token of user.
      */
-    var credential: URLCredential? { get }
+    var credential: URLCredential? { get set }
     
     /**
      Returns an Array of `FileObject`s identifying the the directory entries via asynchronous completion handler.
@@ -66,8 +66,8 @@ public protocol FileProviderBasic: class {
      
      - 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.
+        - `contents`: An array of `FileObject` identifying the the directory entries.
+        - `error`: Error returned by system.
      */
     func contentsOfDirectory(path: String, completionHandler: @escaping ((_ contents: [FileObject], _ error: Error?) -> Void))
     
@@ -78,8 +78,8 @@ public protocol FileProviderBasic: class {
      
      - 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.
+        - `attributes`: A `FileObject` containing the attributes of the item.
+        - `error`: Error returned by system.
      */
     func attributesOfItem(path: String, completionHandler: @escaping ((_ attributes: FileObject?, _ error: Error?) -> Void))
     
@@ -132,6 +132,15 @@ public protocol FileProviderBasic: class {
     */
     func url(of path: String?) -> URL
     
+    
+    /// Returns the relative path of url, wothout percent encoding. Even if url is absolute or
+    /// retrieved from another provider, it will try to resolve the url against `baseURL` of
+    /// current provider. It's highly recomended to use this method for displaying purposes.
+    ///
+    /// - Parameter url: Absolute url to file or directory.
+    /// - Returns: A `String` contains relative path of url against base url.
+    func relativePathOf(url: URL) -> String
+    
     /// Checks the connection to server or permission on local
     func isReachable(completionHandler: @escaping(_ success: Bool) -> Void)
 }
@@ -142,12 +151,6 @@ extension FileProviderBasic {
         self.searchFiles(path: path, recursive: recursive, query: predicate, foundItemHandler: foundItemHandler, completionHandler: completionHandler)
     }
     
-    /// Converts Spotlight search predicate to `FileProvider.searchFiles()` method usable predicate.
-    @available(*, obsoleted: 1.0, renamed: "FileObject.convertProdicate(fromSpotlight:)", message: "Use FileObject.convertProdicate(fromSpotlight:) instead.")
-    public func convertSpotlightPredicateTo(_ query: NSPredicate) -> NSPredicate {
-        return FileObject.convertPredicate(fromSpotlight: query)
-    }
-    
     /// The maximum number of queued operations that can execute at the same time.
     ///
     /// The default value of this property is `OperationQueue.defaultMaxConcurrentOperationCount`.
@@ -159,6 +162,8 @@ extension FileProviderBasic {
             operation_queue.maxConcurrentOperationCount = newValue
         }
     }
+    
+    
 }
 
 /// Checking equality of two file provider, regardless of current path queues and delegates.
@@ -199,7 +204,13 @@ public protocol FileProviderBasicRemote: FileProviderBasic {
     var validatingCache: Bool { get set }
 }
 
-internal extension FileProviderBasicRemote {
+internal protocol FileProviderBasicRemoteInternal: FileProviderBasic {
+    var completionHandlersForTasks: [Int: SimpleCompletionHandler] { get set }
+    var downloadCompletionHandlersForTasks: [Int: (URL) -> Void] { get set }
+    var dataCompletionHandlersForTasks: [Int: (Data) -> Void] { get set }
+}
+
+internal extension FileProviderBasicRemote {    
     func returnCachedDate(with request: URLRequest, validatingCache: Bool, completionHandler: @escaping (Data?, URLResponse?, Error?) -> Swift.Void) -> Bool {
         guard let cache = self.cache else { return false }
         if let response = cache.cachedResponse(for: request) {
@@ -265,20 +276,6 @@ public protocol FileProviderOperations: FileProviderBasic {
     @discardableResult
     func create(folder: String, at: String, completionHandler: SimpleCompletionHandler) -> OperationHandle?
     
-    /**
-     Creates an new file with data passed to method asynchronously. 
-     Returns error via completionHandler if file is already exists.
-     
-     - Parameters:
-       - file: New file name with extension separated by period.
-       - at: Parent path of new file.
-       - data: Data of new files. Pass nil or `Data()` to create empty file.
-       - completionHandler: If an error parameter was provided, a presentable `Error` will be returned.
-     - Returns: An `OperationHandle` to get progress or cancel progress. Doesn't work on `LocalFileProvider`.
-     */
-    @discardableResult
-    func create(file: String, at: String, contents data: Data?, completionHandler: SimpleCompletionHandler) -> OperationHandle?
-    
     /**
      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.
@@ -353,6 +350,8 @@ public protocol FileProviderOperations: FileProviderBasic {
      Uploads a file from local file url to designated path asynchronously.
      Method will fail if source is not a local url with `file://` scheme.
      
+     - Note: It's safe to assume that this method only works on individual files and **won't** copy folders recursively.
+     
      - Parameters:
        - localFile: a file url to file.
        - to: destination path of file, including file/directory name.
@@ -366,6 +365,8 @@ public protocol FileProviderOperations: FileProviderBasic {
      Uploads a file from local file url to designated path asynchronously.
      Method will fail if source is not a local url with `file://` scheme.
      
+     - Note: It's safe to assume that this method only works on individual files and **won't** copy folders recursively.
+     
      - Parameters:
        - localFile: a file url to file.
        - to: destination path of file, including file/directory name.
@@ -380,6 +381,8 @@ public protocol FileProviderOperations: FileProviderBasic {
      Download a file from `path` to designated local file url asynchronously.
      Method will fail if destination is not a local url with `file://` scheme.
      
+     - Note: It's safe to assume that this method only works on individual files and **won't** copy folders recursively.
+     
      - Parameters:
        - path: original file or directory path.
        - toLocalURL: destination local url of file, including file/directory name.
@@ -390,7 +393,15 @@ public protocol FileProviderOperations: FileProviderBasic {
     func copyItem(path: String, toLocalURL: URL, completionHandler: SimpleCompletionHandler) -> OperationHandle?
 }
 
-extension FileProviderOperations {
+public extension FileProviderOperations {
+    /// *DEPRECATED:* Use Use FileProviderReadWrite.writeContents(path:, data:, completionHandler:) method instead.
+    @available(*, deprecated, message: "Use FileProviderReadWrite.writeContents(path:, data:, completionHandler:) method instead.")
+    @discardableResult
+    public func create(file: String, at: String, contents data: Data?, completionHandler: SimpleCompletionHandler) -> OperationHandle? {
+        let path = (at as NSString).appendingPathComponent(file)
+        return (self as? FileProviderReadWrite)?.writeContents(path: path, contents: data, completionHandler: completionHandler)
+    }
+    
     @discardableResult
     public func moveItem(path: String, to: String, completionHandler: SimpleCompletionHandler) -> OperationHandle? {
         return self.moveItem(path: path, to: to, overwrite: false, completionHandler: completionHandler)
@@ -416,8 +427,8 @@ public protocol FileProviderReadWrite: FileProviderBasic {
      - 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.
+         - `contents`: contents of file in a `Data` object.
+         - `error`: Error returned by system.
      - Returns: An `OperationHandle` to get progress or cancel progress. Doesn't work on `LocalFileProvider`.
     */
     @discardableResult
@@ -432,8 +443,8 @@ public protocol FileProviderReadWrite: FileProviderBasic {
        - 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.
+         - `contents`: contents of file in a `Data` object.
+         - `error`: Error returned by system.
      - Returns: An `OperationHandle` to get progress or cancel progress. Doesn't work on `LocalFileProvider`.
      */
     @discardableResult
@@ -446,12 +457,12 @@ public protocol FileProviderReadWrite: FileProviderBasic {
      
      - Parameters:
        - path: Path of target file.
-       - contents: Data to be written into file.
+       - contents: Data to be written into file, pass nil to create empty file.
        - completionHandler: If an error parameter was provided, a presentable `Error` will be returned.
      - Returns: An `OperationHandle` to get progress or cancel progress. Doesn't work on `LocalFileProvider`.
      */
     @discardableResult
-    func writeContents(path: String, contents: Data, completionHandler: SimpleCompletionHandler) -> OperationHandle?
+    func writeContents(path: String, contents: Data?, completionHandler: SimpleCompletionHandler) -> OperationHandle?
     
     /**
      Write the contents of the `Data` to a location asynchronously.
@@ -459,13 +470,13 @@ public protocol FileProviderReadWrite: FileProviderBasic {
      
      - Parameters:
        - path: Path of target file.
-       - contents: Data to be written into file.
+       - contents: Data to be written into file, pass nil to create empty file.
        - 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: An `OperationHandle` to get progress or cancel progress. Doesn't work on `LocalFileProvider`.
      */
     @discardableResult
-    func writeContents(path: String, contents: Data, atomically: Bool, completionHandler: SimpleCompletionHandler) -> OperationHandle?
+    func writeContents(path: String, contents: Data?, atomically: Bool, completionHandler: SimpleCompletionHandler) -> OperationHandle?
     
     /**
      Write the contents of the `Data` to a location asynchronously.
@@ -473,27 +484,27 @@ public protocol FileProviderReadWrite: FileProviderBasic {
      
      - Parameters:
      - path: Path of target file.
-       - contents: Data to be written into file.
+       - contents: Data to be written into file, pass nil to create empty file.
        - 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: An `OperationHandle` to get progress or cancel progress. Doesn't work on `LocalFileProvider`.
      */
     @discardableResult
-    func writeContents(path: String, contents: Data, overwrite: Bool, completionHandler: SimpleCompletionHandler) -> OperationHandle?
+    func writeContents(path: String, contents: Data?, overwrite: Bool, completionHandler: SimpleCompletionHandler) -> OperationHandle?
     
     /**
      Write the contents of the `Data` to a location asynchronously.
      
      - Parameters:
        - path: Path of target file.
-       - contents: Data to be written into file.
+       - contents: Data to be written into file, pass nil to create empty 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: An `OperationHandle` to get progress or cancel progress. Doesn't work on `LocalFileProvider`.
      */
     @discardableResult
-    func writeContents(path: String, contents: Data, atomically: Bool, overwrite: Bool, completionHandler: SimpleCompletionHandler) -> OperationHandle?
+    func writeContents(path: String, contents: Data?, atomically: Bool, overwrite: Bool, completionHandler: SimpleCompletionHandler) -> OperationHandle?
 }
 
 extension FileProviderReadWrite {
@@ -503,17 +514,17 @@ extension FileProviderReadWrite {
     }
     
     @discardableResult
-    public func writeContents(path: String, contents: Data, completionHandler: SimpleCompletionHandler) -> OperationHandle? {
+    public func writeContents(path: String, contents: Data?, completionHandler: SimpleCompletionHandler) -> OperationHandle? {
         return self.writeContents(path: path, contents: contents, atomically: false, overwrite: false, completionHandler: completionHandler)
     }
     
     @discardableResult
-    public func writeContents(path: String, contents: Data, atomically: Bool, completionHandler: SimpleCompletionHandler) -> OperationHandle? {
+    public func writeContents(path: String, contents: Data?, atomically: Bool, completionHandler: SimpleCompletionHandler) -> OperationHandle? {
         return self.writeContents(path: path, contents: contents, atomically: atomically, overwrite: false, completionHandler: completionHandler)
     }
     
     @discardableResult
-    public func writeContents(path: String, contents: Data, overwrite: Bool, completionHandler: SimpleCompletionHandler) -> OperationHandle? {
+    public func writeContents(path: String, contents: Data?, overwrite: Bool, completionHandler: SimpleCompletionHandler) -> OperationHandle? {
         return self.writeContents(path: path, contents: contents, atomically: false, overwrite: overwrite, completionHandler: completionHandler)
     }
 }
@@ -600,21 +611,39 @@ public extension FileProvideUndoable {
     }
 }
 
+/// This protocol defines method to share a public link with other users
+public protocol FileProviderSharing {
+    /**
+     Genrates a public url to a file to be shared with other users and can be downloaded without authentication.
+     
+     - Important: In some providers url will be available for a limitied time, determined in `expiration` argument.
+         e.g. Dropbox links will be expired after 4 hours.
+     
+     - Parameters:
+         - to: path of file, including file/directory name.
+         - completionHandler: a closure with result of directory entries or error.
+             - `link`: a url returned by Dropbox to share.
+             - `attribute`: a `FileObject` containing the attributes of the item.
+             - `expiration`: a `Date` object, determines when the public url will expires.
+             - `error`: Error returned by server.
+     */
+    func publicLink(to path: String, completionHandler: @escaping ((_ link: URL?, _ attribute: FileObject?, _ expiration: Date?, _ error: Error?) -> Void))
+}
+
 /// Defines protocol for provider allows all common operations.
-public protocol FileProvider: FileProviderBasic, FileProviderOperations, FileProviderReadWrite, NSCopying {
+public protocol FileProvider: FileProviderOperations, FileProviderReadWrite, NSCopying {
 }
 
 internal let pathTrimSet = CharacterSet(charactersIn: " /")
 extension FileProviderBasic {
     public var type: String {
+        #if swift(>=3.1)
+        return Swift.type(of: self).type
+        #else
         return type(of: self).type
+        #endif
     }
     
-    /// **DEPRECATED** This property never worked as expected and is redundant as only supported by `LocalFileProvider`.
-    /// To simulate `false` value, assign `URL(fileURLWithPath: "/")` to `baseURL`.
-    @available(*, deprecated, message: "Redundant property, now is always true.")
-    var isPathRelative: Bool { return true }
-    
     public func url(of path: String? = nil) -> URL {
         var rpath: String = path ?? self.currentPath
         rpath = rpath.addingPercentEncoding(withAllowedCharacters: .urlPathAllowed) ?? rpath
@@ -628,26 +657,29 @@ extension FileProviderBasic {
         }
     }
     
-    
-    /// Returns the relative path of url, wothout percent encoding. Even if url is absolute or
-    /// retrieved from another provider, it will try to resolve the url against `baseURL` of
-    /// current provider. It's highly recomended to use this method for displaying purposes.
-    ///
-    /// - Parameter url: Absolute url to file or directory.
-    /// - Returns: A `String` contains relative path of url against base url.
     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
+            return (relativePath.removingPercentEncoding ?? relativePath).replacingOccurrences(of: "/", with: "", options: .anchored)
         }
         
         // resolve url string against baseurl
-        guard let baseURL = self.baseURL?.standardizedFileURL else { return url.absoluteString }
-        let standardPath = url.absoluteString.replacingOccurrences(of: "file:///private/var/", with: "file:///var/", options: .anchored)
-        let standardBase = baseURL.absoluteString.replacingOccurrences(of: "file:///private/var/", with: "file:///var/", options: .anchored)
-        let standardRelativePath = standardPath.replacingOccurrences(of: standardBase, with: "/")
-        return standardRelativePath.removingPercentEncoding ?? standardRelativePath
+        if baseURL?.isFileURL ?? false {
+            guard let baseURL = self.baseURL?.standardizedFileURL else { return url.absoluteString }
+            let standardPath = url.absoluteString.replacingOccurrences(of: "file:///private/var/", with: "file:///var/", options: .anchored)
+            let standardBase = baseURL.absoluteString.replacingOccurrences(of: "file:///private/var/", with: "file:///var/", options: .anchored)
+            let standardRelativePath = standardPath.replacingOccurrences(of: standardBase, with: "/").replacingOccurrences(of: "/", with: "", options: .anchored)
+            return standardRelativePath.removingPercentEncoding ?? standardRelativePath
+        } else {
+            guard let baseURL = self.baseURL else { return url.absoluteString }
+            let standardRelativePath = url.absoluteString.replacingOccurrences(of: baseURL.absoluteString, with: "/").replacingOccurrences(of: "/", with: "", options: .anchored)
+            if URLComponents(string: standardRelativePath)?.host?.isEmpty ?? true {
+                return standardRelativePath.removingPercentEncoding ?? standardRelativePath
+            } else {
+                return relativePath.replacingOccurrences(of: "/", with: "", options: .anchored)
+            }
+        }
     }
     
     internal func correctPath(_ path: String?) -> String? {
@@ -682,7 +714,7 @@ extension FileProviderBasic {
             }
             var i = number ?? 2
             let similiar = contents.map {
-                $0.url?.lastPathComponent ?? $0.name
+                $0.url.lastPathComponent.isEmpty ? $0.name : $0.url.lastPathComponent
             }.filter {
                 $0.hasPrefix(result)
             }
@@ -702,6 +734,8 @@ extension FileProviderBasic {
         let domain: String
         switch code {
         case is URLError:
+            fallthrough
+        case is URLError.Code:
             domain = NSURLErrorDomain
         default:
             domain = NSCocoaErrorDomain
@@ -736,8 +770,8 @@ public protocol ExtendedFileProvider: FileProviderBasic {
      - Parameters:
        - path: path of file.
        - completionHandler: a closure with result of preview image or error.
-         `image`: `NSImage`/`UIImage` object contains preview.
-         `error`: Error returned by system.
+         - `image`: `NSImage`/`UIImage` object contains preview.
+         - `error`: Error returned by system.
     */
     func thumbnailOfFile(path: String, completionHandler: @escaping ((_ image: ImageClass?, _ error: Error?) -> Void))
     
@@ -752,8 +786,8 @@ public protocol ExtendedFileProvider: FileProviderBasic {
        - path: path of file.
        - dimension: width and height of result preview image.
        - completionHandler: a closure with result of preview image or error.
-         `image`: `NSImage`/`UIImage` object contains preview.
-     `error`: Error returned by system.
+         - `image`: `NSImage`/`UIImage` object contains preview.
+         - `error`: Error returned by system.
      */
     func thumbnailOfFile(path: String, dimension: CGSize?, completionHandler: @escaping ((_ image: ImageClass?, _ error: Error?) -> Void))
     
@@ -767,9 +801,9 @@ public protocol ExtendedFileProvider: FileProviderBasic {
      - Parameters:
        - path: path of file.
        - completionHandler: a closure with result of preview image or error.
-         `propertiesDictionary`: A `Dictionary` of proprty keys and values.
-         `keys`: An `Array` contains ordering of keys.
-         `error`: Error returned by system.
+         - `propertiesDictionary`: A `Dictionary` of proprty keys and values.
+         - `keys`: An `Array` contains ordering of keys.
+         - `error`: Error returned by system.
      */
     func propertiesOfFile(path: String, completionHandler: @escaping ((_ propertiesDictionary: [String: Any], _ keys: [String], _ error: Error?) -> Void))
 }
@@ -833,19 +867,20 @@ extension ExtendedFileProvider {
             return resultingImage
         #else
             let ppp = Int(UIScreen.main.scale) // fetch device is retina or not
-            guard let context = UIGraphicsGetCurrentContext() else {
-                return nil
-            }
             size.width  *= CGFloat(ppp)
             size.height *= CGFloat(ppp)
             UIGraphicsBeginImageContext(size)
-            
+            guard let context = UIGraphicsGetCurrentContext() else {
+                return nil
+            }
             context.saveGState()
             let transform = pdfPage.getDrawingTransform(CGPDFBox.mediaBox, rect: rect, rotate: 0, preserveAspectRatio: true)
             context.concatenate(transform)
             
             context.translateBy(x: 0, y: size.height)
             context.scaleBy(x: CGFloat(ppp), y: CGFloat(-ppp))
+            context.setFillColor(UIColor.white.cgColor)
+            context.fill(rect)
             context.drawPDFPage(pdfPage)
             
             context.restoreGState()
@@ -942,6 +977,8 @@ public enum FileOperationType: CustomStringConvertible {
         }
         let dest = json["dest"] as? String
         switch type {
+        case "Fetch":
+            self = .fetch(path: source)
         case "Create":
             self = .create(path: source)
         case "Modify":
@@ -1025,16 +1062,11 @@ public protocol FileOperationDelegate: class {
     func fileProvider(_ fileProvider: FileProviderOperations, shouldProceedAfterError error: Error, operation: FileOperationType) -> Bool
 }
 
-internal class Weak<T: AnyObject> {
-    weak var value : T?
-    init (_ value: T) {
-        self.value = value
-    }
-}
-
 /// For internal use in `FileProvider` framework
 public protocol FoundationErrorEnum {
+    /// Init from error code
     init? (rawValue: Int)
+    // Raw error code
     var rawValue: Int { get }
 }
 

Sources/FileProviderExtensions.swift

@@ -8,7 +8,7 @@
 
 import Foundation
 
-extension Array where Element: FileObject {
+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)
@@ -21,8 +21,8 @@ extension Array where Element: FileObject {
     }
 }
 
-extension URLFileResourceType {
-    /// Returns corresponding `URLFileResourceType` of a `FileAttributeType` value
+public extension URLFileResourceType {
+    /// **FileProvider** returns corresponding `URLFileResourceType` of a `FileAttributeType` value
     public init(fileTypeValue: FileAttributeType) {
         switch fileTypeValue {
         case FileAttributeType.typeCharacterSpecial: self = .characterSpecial
@@ -37,11 +37,17 @@ extension URLFileResourceType {
     }
 }
 
-internal extension URLResourceKey {
-    static let fileURL = URLResourceKey(rawValue: "NSURLFileURLKey")
-    static let serverDate = URLResourceKey(rawValue: "NSURLServerDateKey")
-    static let entryTag = URLResourceKey(rawValue: "NSURLEntryTagKey")
-    static let mimeType = URLResourceKey(rawValue: "NSURLMIMETypeIdentifierKey")
+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")
 }
 
 internal extension URL {
@@ -62,6 +68,58 @@ internal extension URL {
     }
 }
 
+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")
+    }
+    
+    mutating func set(dropboxArgKey requestDictionary: [String: AnyObject]) {
+        if let requestJson = String(jsonDictionary: requestDictionary) {
+            self.setValue(requestJson, forHTTPHeaderField: "Dropbox-API-Arg")
+        }
+    }
+}
+
 internal extension Data {
     internal var isPDF: Bool {
         return self.count > 4 && self.scanString(length: 4, using: .ascii) == "%PDF"
@@ -151,7 +209,44 @@ internal extension TimeInterval {
     }
 }
 
-extension NSPredicate {
+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

Sources/LocalFileProvider.swift

@@ -21,7 +21,7 @@ open class LocalFileProvider: FileProvider, FileProviderMonitor, FileProvideUndo
     open var dispatch_queue: DispatchQueue
     open var operation_queue: OperationQueue
     open weak var delegate: FileProviderDelegate?
-    open internal(set) var credential: URLCredential?
+    open var credential: URLCredential?
     
     /// Underlying `FileManager` object for listing and metadata fetching.
     open private(set) var fileManager = FileManager()
@@ -42,12 +42,6 @@ open class LocalFileProvider: FileProvider, FileProviderMonitor, FileProvideUndo
     */
     open var isCoorinating: Bool
     
-    /// **OBSOLETED**: Use FileProvider.init(for:in:) instead.
-    @available(*, obsoleted: 1.0, renamed: "init(for:in:)", message: "Use FileProvider.init(for:in:) instead.")
-    public convenience init (directory: FileManager.SearchPathDirectory = .documentDirectory, domainMask: FileManager.SearchPathDomainMask = .userDomainMask) {
-        self.init(baseURL: FileManager.default.urls(for: directory, in: domainMask).first!)
-    }
-    
     /**
      Initializes provider for the specified common directory in the requested domains.
      default values are `directory: .documentDirectory, domainMask: .userDomainMask`.
@@ -76,7 +70,7 @@ open class LocalFileProvider: FileProvider, FileProviderMonitor, FileProvideUndo
             return nil
         }
         
-        var finalBaseURL = baseURL
+        var finalBaseURL = baseURL.absoluteURL
         
         switch directory {
         case .documentDirectory:
@@ -104,24 +98,51 @@ open class LocalFileProvider: FileProvider, FileProviderMonitor, FileProvideUndo
         guard baseURL.isFileURL else {
             fatalError("Cannot initialize a Local provider from remote URL.")
         }
-        self.baseURL = baseURL
+        self.baseURL = (baseURL.absoluteString.hasSuffix("/") ? baseURL : baseURL.appendingPathComponent("")).absoluteURL
         self.currentPath = ""
         self.credential = nil
         self.isCoorinating = false
         
-        dispatch_queue = DispatchQueue(label: "FileProvider.\(type(of: self).type)", attributes: .concurrent)
+        #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 = "FileProvider.\(type(of: self).type).Operation"
+        operation_queue.name = "\(queueLabel).Operation"
         
         fileProviderManagerDelegate = LocalFileProviderManagerDelegate(provider: self)
         opFileManager.delegate = fileProviderManagerDelegate
-        
     }
     
-    /// **DEPRECATED:** No longer is in use and overriding this method has no effect anymore.
-    @available(*, deprecated, message: "Overriding this method has no effect anymore.")
-    open class func defaultBaseURL() -> URL {
-        return FileManager.default.urls(for: .documentDirectory, in: .userDomainMask).first!
+    public required convenience init?(coder aDecoder: NSCoder) {
+        guard let baseURL = aDecoder.decodeObject(forKey: "baseURL") as? URL else {
+            return nil
+        }
+        self.init(baseURL: baseURL)
+        self.currentPath   = aDecoder.decodeObject(forKey: "currentPath") as? String ?? ""
+        self.isCoorinating = aDecoder.decodeBool(forKey: "isCoorinating")
+    }
+    
+    open func encode(with aCoder: NSCoder) {
+        aCoder.encode(self.baseURL, forKey: "currentPath")
+        aCoder.encode(self.currentPath, forKey: "currentPath")
+        aCoder.encode(self.isCoorinating, forKey: "isCoorinating")
+    }
+    
+    public static var supportsSecureCoding: Bool {
+        return true
+    }
+    
+    public func copy(with zone: NSZone? = nil) -> Any {
+        let copy = LocalFileProvider(baseURL: self.baseURL!)
+        copy.currentPath = self.currentPath
+        copy.undoManager = self.undoManager
+        copy.isCoorinating = self.isCoorinating
+        copy.delegate = self.delegate
+        copy.fileOperationDelegate = self.fileOperationDelegate
+        return copy
     }
     
     open func contentsOfDirectory(path: String, completionHandler: @escaping ((_ contents: [FileObject], _ error: Error?) -> Void)) {
@@ -184,15 +205,6 @@ open class LocalFileProvider: FileProvider, FileProviderMonitor, FileProvideUndo
         return self.doOperation(opType, completionHandler: completionHandler)
     }
     
-    @discardableResult
-    open func create(file fileName: String, at atPath: String, contents data: Data?, completionHandler: SimpleCompletionHandler) -> OperationHandle? {
-        let fileName = fileName.trimmingCharacters(in: CharacterSet(charactersIn: "/"))
-        let path = (atPath as NSString).appendingPathComponent(fileName)
-        let opType = FileOperationType.create(path: path)
-        
-        return self.doOperation(opType, data: data, atomically: true, completionHandler: completionHandler)
-    }
-    
     @discardableResult
     open func moveItem(path: String, to toPath: String, overwrite: Bool = false, completionHandler: SimpleCompletionHandler) -> OperationHandle? {
         let opType = FileOperationType.move(source: path, destination: toPath)
@@ -243,7 +255,7 @@ open class LocalFileProvider: FileProvider, FileProviderMonitor, FileProvideUndo
         return self.doOperation(opType, completionHandler: completionHandler)
     }
     
-    dynamic func doSimpleOperation(_ box: UndoBox) {
+    @objc dynamic func doSimpleOperation(_ box: UndoBox) {
         guard let _ = self.undoManager else { return }
         _ = self.doOperation(box.undoOperation) { (_) in
             return
@@ -252,7 +264,8 @@ open class LocalFileProvider: FileProvider, FileProviderMonitor, FileProvideUndo
     
     @discardableResult
     fileprivate func doOperation(_ opType: FileOperationType, data: Data? = nil, atomically: Bool = false, forUploading: Bool = false, completionHandler: SimpleCompletionHandler) -> OperationHandle? {
-        
+        let localOperationHandle = LocalOperationHandle(operationType: opType, baseURL: self.baseURL)
+
         func urlofpath(path: String) -> URL {
             if path.hasPrefix("file://") {
                 let removedSchemePath = path.replacingOccurrences(of: "file://", with: "", options: .anchored)
@@ -286,6 +299,7 @@ open class LocalFileProvider: FileProvider, FileProviderMonitor, FileProvideUndo
         
         let operationHandler: (URL, URL?) -> Void = { source, dest in
             do {
+                localOperationHandle.inProgress = true
                 switch opType {
                 case .create:
                     if sourcePath.hasSuffix("/") {
@@ -309,7 +323,8 @@ open class LocalFileProvider: FileProvider, FileProviderMonitor, FileProvideUndo
                 if successfulSecurityScopedResourceAccess {
                     source.stopAccessingSecurityScopedResource()
                 }
-                
+
+                localOperationHandle.inProgress = false
                 self.dispatch_queue.async {
                     completionHandler?(nil)
                 }
@@ -361,18 +376,20 @@ open class LocalFileProvider: FileProvider, FileProviderMonitor, FileProvideUndo
                 operationHandler(source, dest)
             }
         }
-        
-        return LocalOperationHandle(operationType: opType, baseURL: self.baseURL)
+        return localOperationHandle
     }
     
     @discardableResult
     open func contents(path: String, completionHandler: @escaping ((_ contents: Data?, _ error: Error?) -> Void)) -> OperationHandle? {
         let opType = FileOperationType.fetch(path: path)
+        let localOperationHandle = LocalOperationHandle(operationType: opType, baseURL: self.baseURL)
         let url = self.url(of: path)
-        
+
         let operationHandler: (URL) -> Void = { url in
             do {
+                localOperationHandle.inProgress = true
                 let data = try Data(contentsOf: url)
+                localOperationHandle.inProgress = false
                 self.dispatch_queue.async {
                     completionHandler(data, nil)
                 }
@@ -398,8 +415,8 @@ open class LocalFileProvider: FileProvider, FileProviderMonitor, FileProvideUndo
                 operationHandler(url)
             }
         }
-        
-        return LocalOperationHandle(operationType: opType, baseURL: self.baseURL)
+
+        return localOperationHandle
     }
     
     @discardableResult
@@ -410,12 +427,13 @@ open class LocalFileProvider: FileProvider, FileProviderMonitor, FileProvideUndo
             }
             return nil
         }
-        
+
         if offset == 0 && length < 0 {
             return self.contents(path: path, completionHandler: completionHandler)
         }
-        
+
         let opType = FileOperationType.fetch(path: path)
+        let localOperationHandle = LocalOperationHandle(operationType: opType, baseURL: self.baseURL)
         let url = self.url(of: path)
         
         let operationHandler: (URL) -> Void = { url in
@@ -429,9 +447,11 @@ open class LocalFileProvider: FileProvider, FileProviderMonitor, FileProvideUndo
             defer {
                 handle.closeFile()
             }
-            
+
+            localOperationHandle.inProgress = true
             let size = LocalFileObject(fileWithURL: url)?.size ?? -1
             guard size > offset else {
+                localOperationHandle.inProgress = false
                 self.dispatch_queue.async {
                     completionHandler(nil, self.throwError(path, code: CocoaError.fileReadTooLarge as FoundationErrorEnum))
                 }
@@ -439,6 +459,7 @@ open class LocalFileProvider: FileProvider, FileProviderMonitor, FileProvideUndo
             }
             handle.seek(toFileOffset: UInt64(offset))
             guard Int64(handle.offsetInFile) == offset else {
+                localOperationHandle.inProgress = false
                 self.dispatch_queue.async {
                     completionHandler(nil, self.throwError(path, code: CocoaError.fileReadTooLarge as FoundationErrorEnum))
                 }
@@ -446,7 +467,7 @@ open class LocalFileProvider: FileProvider, FileProviderMonitor, FileProvideUndo
             }
             
             let data = handle.readData(ofLength: length)
-            
+            localOperationHandle.inProgress = false
             self.dispatch_queue.async {
                 completionHandler(data, nil)
             }
@@ -466,13 +487,14 @@ open class LocalFileProvider: FileProvider, FileProviderMonitor, FileProvideUndo
             }
         }
         
-        return LocalOperationHandle(operationType: opType, baseURL: self.baseURL)
+        return localOperationHandle
     }
     
     @discardableResult
-    open func writeContents(path: String, contents data: Data, atomically: Bool, overwrite: Bool, completionHandler: SimpleCompletionHandler) -> OperationHandle? {
-        let opType = FileOperationType.modify(path: path)
-        return self.doOperation(opType, data: data, atomically: atomically, completionHandler: completionHandler)
+    open func writeContents(path: String, contents data: Data?, atomically: Bool, overwrite: Bool, completionHandler: SimpleCompletionHandler) -> OperationHandle? {
+        let fileExists = fileManager.fileExists(atPath: url(of: path).path)
+        let opType: FileOperationType = fileExists ? .modify(path: path) : .create(path: path)
+        return self.doOperation(opType, data: data ?? Data(), atomically: atomically, completionHandler: completionHandler)
     }
     
     fileprivate var monitors = [LocalFolderMonitor]()
@@ -505,28 +527,18 @@ open class LocalFileProvider: FileProvider, FileProviderMonitor, FileProvideUndo
     open func isRegisteredForNotification(path: String) -> Bool {
         return monitors.map( { self.relativePathOf(url: $0.url) } ).contains(path.trimmingCharacters(in: CharacterSet(charactersIn: "/")))
     }
-    
-    open func copy(with zone: NSZone? = nil) -> Any {
-        let copy = LocalFileProvider(baseURL: self.baseURL!)
-        copy.currentPath = self.currentPath
-        copy.undoManager = self.undoManager
-        copy.isCoorinating = self.isCoorinating
-        copy.delegate = self.delegate
-        copy.fileOperationDelegate = self.fileOperationDelegate
-        return copy
-    }
 }
 
 public extension LocalFileProvider {
     /**
      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 destURL, making it possible 
-     to create symbolic links to locations that do not yet exist. 
-     Also, if the final path component in url is a symbolic link, that link is not followed.
+     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.
     
      - Parameters:
-       - path: The file path at which to create the new symbolic link. The last component of the path issued as the name of the link.
-       - destPath: The path that contains the item to be pointed to by the link. In other words, this is the destination of the link.
+       - 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) {

Sources/LocalHelper.swift

@@ -10,7 +10,7 @@ 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) {
+    internal override init(url: URL?, name: String, path: String) {
         super.init(url: url, name: name, path: path)
     }
     
@@ -24,7 +24,8 @@ public final class LocalFileObject: FileObject {
         if #available(iOS 9.0, macOS 10.11, tvOS 9.0, *) {
             fileURL = URL(fileURLWithPath: rpath, relativeTo: relativeURL)
         } else {
-            fileURL = URL(string: rpath.isEmpty ? "./" : rpath, relativeTo: relativeURL)
+            rpath = rpath.addingPercentEncoding(withAllowedCharacters: .urlPathAllowed) ?? rpath
+            fileURL = URL(string: rpath, relativeTo: relativeURL) ?? relativeURL
         }
         
         if let fileURL = fileURL {
@@ -37,7 +38,7 @@ public final class LocalFileObject: FileObject {
     /// Initiates a `LocalFileObject` with attributes of file in url.
     public convenience init?(fileWithURL fileURL: URL) {
         do {
-            let values = try fileURL.resourceValues(forKeys: [.nameKey, .fileSizeKey, .fileAllocatedSizeKey, .creationDateKey, .contentModificationDateKey, .fileResourceTypeKey, .isHiddenKey, .isWritableKey, .typeIdentifierKey, .generationIdentifierKey, .documentIdentifierKey])
+            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)
@@ -216,14 +217,17 @@ internal class LocalFileProviderManagerDelegate: NSObject, FileManagerDelegate {
     }
 }
 
-/// Local operation handling is limited. Please don't use as much as possible.
+/// - Note: Local operation handling is limited. Please don't use as much as possible.
 open class LocalOperationHandle: OperationHandle {
+    /// Url of file which operation is doing on
     public let baseURL: URL
+    /// Type of operation
     public let operationType: FileOperationType
     
     init (operationType: FileOperationType, baseURL: URL?) {
         self.baseURL = baseURL ?? URL(fileURLWithPath: "/")
         self.operationType = operationType
+        inProgress = false
     }
     
     private var sourceURL: URL? {
@@ -277,10 +281,9 @@ open class LocalOperationHandle: OperationHandle {
     }
     
     /// Not usable in local provider
-    open var inProgress: Bool {
-        return false
-    }
-    
+    open var inProgress: Bool
+
+
     /// Not usable in local provider
     open func cancel() -> Bool{
         return false

Sources/OneDriveFileProvider.swift

@@ -33,7 +33,11 @@ open class OneDriveFileProvider: FileProviderBasicRemote {
     }
     
     open weak var delegate: FileProviderDelegate?
-    open let credential: URLCredential?
+    open var credential: URLCredential? {
+        didSet {
+            sessionDelegate?.credential = self.credential
+        }
+    }
     open private(set) var cache: URLCache?
     public var useCache: Bool
     public var validatingCache: Bool
@@ -41,16 +45,30 @@ open class OneDriveFileProvider: FileProviderBasicRemote {
     fileprivate var _session: URLSession?
     fileprivate var sessionDelegate: SessionDelegate?
     public var session: URLSession {
-        if _session == nil {
-            self.sessionDelegate = SessionDelegate(fileProvider: self, credential: credential)
-            let queue = OperationQueue()
-            //queue.underlyingQueue = dispatch_queue
-            let config = URLSessionConfiguration.default
-            config.urlCache = cache
-            config.requestCachePolicy = .returnCacheDataElseLoad
-            _session = URLSession(configuration: config, delegate: sessionDelegate as URLSessionDelegate?, delegateQueue: queue)
+        get {
+            if _session == nil {
+                self.sessionDelegate = SessionDelegate(fileProvider: self)
+                let queue = OperationQueue()
+                //queue.underlyingQueue = dispatch_queue
+                let config = URLSessionConfiguration.default
+                config.urlCache = cache
+                config.requestCachePolicy = .returnCacheDataElseLoad
+                _session = URLSession(configuration: config, delegate: sessionDelegate as URLSessionDelegate?, delegateQueue: 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!)
         }
-        return _session!
     }
     
     /**
@@ -68,20 +86,62 @@ open class OneDriveFileProvider: FileProviderBasicRemote {
        - 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 ?? URL(string: "https://api.onedrive.com/")!
-        self.baseURL = baseURL.path.hasSuffix("/") ? baseURL : baseURL.appendingPathComponent("")
+        let baseURL = serverURL?.absoluteURL ?? URL(string: "https://api.onedrive.com/")!
+        self.baseURL = baseURL.absoluteString.hasSuffix("/") ? baseURL : baseURL.appendingPathComponent("")
         self.drive = drive
         self.currentPath = ""
         self.useCache = false
         self.validatingCache = true
         self.cache = cache
         self.credential = credential
-        dispatch_queue = DispatchQueue(label: "FileProvider.\(type(of: self).type)", attributes: .concurrent)
+        
+        #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 = "FileProvider.\(type(of: self).type).Operation"
+        operation_queue.name = "\(queueLabel).Operation"
+    }
+    
+    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 func encode(with aCoder: NSCoder) {
+        aCoder.encode(self.credential, forKey: "credential")
+        aCoder.encode(self.baseURL, forKey: "baseURL")
+        aCoder.encode(self.drive, forKey: "drive")
+        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 {
+        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
     }
     
     deinit {
+        if let sessionuuid = _session?.sessionDescription {
+            removeSessionHandler(for: sessionuuid)
+        }
+        
         if fileProviderCancelTasksOnInvalidating {
             _session?.invalidateAndCancel()
         } else {
@@ -98,7 +158,7 @@ open class OneDriveFileProvider: FileProviderBasicRemote {
     open func attributesOfItem(path: String, completionHandler: @escaping ((_ attributes: FileObject?, _ error: Error?) -> Void)) {
         var request = URLRequest(url: url(of: path))
         request.httpMethod = "GET"
-        request.setValue("Bearer \(credential?.password ?? "")", forHTTPHeaderField: "Authorization")
+        request.set(httpAuthentication: credential, with: .oAuth2)
         let task = session.dataTask(with: request, completionHandler: { (data, response, error) in
             var serverError: FileProviderOneDriveError?
             var fileObject: OneDriveFileObject?
@@ -117,7 +177,7 @@ open class OneDriveFileProvider: FileProviderBasicRemote {
     open func storageProperties(completionHandler: @escaping ((_ total: Int64, _ used: Int64) -> Void)) {
         var request = URLRequest(url: url())
         request.httpMethod = "GET"
-        request.setValue("Bearer \(credential?.password ?? "")", forHTTPHeaderField: "Authorization")
+        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
@@ -174,7 +234,7 @@ open class OneDriveFileProvider: FileProviderBasicRemote {
     open func isReachable(completionHandler: @escaping (Bool) -> Void) {
         var request = URLRequest(url: url())
         request.httpMethod = "HEAD"
-        request.setValue("Bearer \(credential?.password ?? "")", forHTTPHeaderField: "Authorization")
+        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)
@@ -193,11 +253,6 @@ extension OneDriveFileProvider: FileProviderOperations {
         return doOperation(.create(path: path), completionHandler: completionHandler)
     }
     
-    open func create(file fileName: String, at path: String, contents data: Data?, completionHandler: SimpleCompletionHandler) -> OperationHandle? {
-        let filePath = (path as NSString).appendingPathComponent(fileName)
-        return self.writeContents(path: filePath, contents: data ?? Data(), completionHandler: completionHandler)
-    }
-    
     open func moveItem(path: String, to toPath: String, overwrite: Bool, completionHandler: SimpleCompletionHandler) -> OperationHandle? {
         return doOperation(.move(source: path, destination: toPath), completionHandler: completionHandler)
     }
@@ -230,10 +285,10 @@ extension OneDriveFileProvider: FileProviderOperations {
             return nil
         }
         
-        request.setValue("Bearer \(credential?.password ?? "")", forHTTPHeaderField: "Authorization")
+        request.set(httpAuthentication: credential, with: .oAuth2)
         var requestDictionary = [String: AnyObject]()
         if let dest = correctPath(destPath) as NSString? {
-            request.setValue("application/json", forHTTPHeaderField: "Content-Type")
+            request.set(contentType: .json)
             requestDictionary["parentReference"] = ("/drive/\(drive):" + dest.deletingLastPathComponent) as NSString
             requestDictionary["name"] = dest.lastPathComponent as NSString
             request.httpBody = Data(jsonDictionary: requestDictionary)
@@ -252,6 +307,14 @@ extension OneDriveFileProvider: FileProviderOperations {
     }
     
     open func copyItem(localFile: URL, to toPath: String, overwrite: Bool, completionHandler: SimpleCompletionHandler) -> OperationHandle? {
+        // 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
@@ -265,23 +328,24 @@ extension OneDriveFileProvider: FileProviderOperations {
             return nil
         }
         var request = URLRequest(url: self.url(of: path, modifier: "content"))
-        request.httpMethod = "GET"
-        request.setValue("Bearer \(credential?.password ?? "")", forHTTPHeaderField: "Authorization")
-        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 errorData : Data? = nil //Data(contentsOf:cacheURL) // TODO: Figure out how to get error response data for the error description
+        request.set(httpAuthentication: credential, with: .oAuth2)
+        let task = session.downloadTask(with: request)
+        completionHandlersForTasks[session.sessionDescription!]?[task.taskIdentifier] = completionHandler
+        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 : FileProviderOneDriveError? = code != nil ? FileProviderOneDriveError(code: code!, path: path, errorDescription: String(data: errorData ?? Data(), encoding: .utf8)) : nil
-                completionHandler?(serverError ?? error)
+                completionHandler?(serverError)
                 return
             }
             do {
-                try FileManager.default.moveItem(at: cacheURL, to: destURL)
+                try FileManager.default.moveItem(at: tempURL, to: destURL)
                 completionHandler?(nil)
             } catch let e {
                 completionHandler?(e)
             }
-        })
+        }
         task.taskDescription = opType.json
         task.resume()
         return RemoteOperationHandle(operationType: opType, tasks: [task])
@@ -300,32 +364,39 @@ extension OneDriveFileProvider: FileProviderReadWrite {
         let opType = FileOperationType.fetch(path: path)
         var request = URLRequest(url: self.url(of: path, modifier: "content"))
         request.httpMethod = "GET"
-        request.setValue("Bearer \(credential?.password ?? "")", forHTTPHeaderField: "Authorization")
-        if length > 0 {
-            request.setValue("bytes=\(offset)-\(offset + length - 1)", forHTTPHeaderField: "Range")
-        } else if offset > 0 && length < 0 {
-            request.setValue("bytes=\(offset)-", forHTTPHeaderField: "Range")
+        request.set(httpAuthentication: credential, with: .oAuth2)
+        request.set(rangeWithOffset: offset, length: length)
+        let task = session.downloadTask(with: request)
+        completionHandlersForTasks[session.sessionDescription!]?[task.taskIdentifier] = { error in
+            completionHandler(nil, error)
         }
-        let task = session.dataTask(with: request, completionHandler: { (data, response, error) in
-            var serverError: FileProviderOneDriveError?
-            if let httpResponse = response as? HTTPURLResponse , httpResponse.statusCode >= 300, let code = FileProviderHTTPErrorCode(rawValue: httpResponse.statusCode) {
-                serverError = FileProviderOneDriveError(code: code, path: path, errorDescription: String(data: data ?? Data(), encoding: .utf8))
+        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 : FileProviderOneDriveError? = code != nil ? FileProviderOneDriveError(code: code!, path: path, errorDescription: String(data: errorData ?? Data(), encoding: .utf8)) : nil
+                completionHandler(nil, serverError)
+                return
             }
-            let filedata = serverError ?? error == nil ? data : nil
-            completionHandler(filedata, serverError ?? error)
-        })
+            do {
+                let data = try Data(contentsOf: tempURL)
+                completionHandler(data, nil)
+            } catch let e {
+                completionHandler(nil, e)
+            }
+        }
         task.taskDescription = opType.json
         task.resume()
         return RemoteOperationHandle(operationType: opType, tasks: [task])
     }
     
-    open func writeContents(path: String, contents data: Data, atomically: Bool, overwrite: Bool, completionHandler: SimpleCompletionHandler) -> OperationHandle? {
+    open func writeContents(path: String, contents data: Data?, atomically: Bool, overwrite: Bool, completionHandler: SimpleCompletionHandler) -> OperationHandle? {
         let opType = FileOperationType.modify(path: path)
         guard fileOperationDelegate?.fileProvider(self, shouldDoOperation: opType) ?? true == true else {
             return nil
         }
         // FIXME: remove 150MB restriction
-        return upload_simple(path, data: data, overwrite: overwrite, operation: opType, completionHandler: completionHandler)
+        return upload_simple(path, data: data ?? Data(), overwrite: overwrite, operation: opType, completionHandler: completionHandler)
     }
     
     fileprivate func registerNotifcation(path: String, eventHandler: (() -> Void)) {
@@ -340,19 +411,10 @@ extension OneDriveFileProvider: FileProviderReadWrite {
     fileprivate func unregisterNotifcation(path: String) {
         NotImplemented()
     }
-    
-    /**
-     Genrates a public url to a file to be shared with other users and can be downloaded without authentication.
-     
-     - Parameters:
-       - to: path of file, including file/directory name.
-       - completionHandler: a closure with result of directory entries or error.
-         `link`: a url returned by OneDrive to share.
-         `attribute`: `nil` for OneDrive.
-         `expiration`: `nil` for OneDrive, as it doesn't expires.
-         `error`: Error returned by OneDrive.
-     */
-    open func publicLink(to path: String, completionHandler: @escaping ((_ link: URL?, _ attribute: OneDriveFileObject?, _ expiration: Date?, _ error: Error?) -> Void)) {
+}
+
+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]
@@ -405,7 +467,7 @@ extension OneDriveFileProvider: ExtendedFileProvider {
         }
         
         var request = URLRequest(url: url)
-        request.setValue("Bearer \(credential?.password ?? "")", forHTTPHeaderField: "Authorization")
+        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) {
@@ -424,7 +486,7 @@ extension OneDriveFileProvider: ExtendedFileProvider {
     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.setValue("Bearer \(credential?.password ?? "")", forHTTPHeaderField: "Authorization")
+        request.set(httpAuthentication: credential, with: .oAuth2)
         let task = session.dataTask(with: request, completionHandler: { (data, response, error) in
             var serverError: FileProviderOneDriveError?
             var dic = [String: Any]()
@@ -442,14 +504,4 @@ extension OneDriveFileProvider: ExtendedFileProvider {
     }
 }
 
-extension OneDriveFileProvider: FileProvider {
-    open 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
-    }
-}
+extension OneDriveFileProvider: FileProvider { }

Sources/OneDriveHelper.swift

@@ -18,11 +18,11 @@ public struct FileProviderOneDriveError: FileProviderHTTPError {
 /// 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 = path
-        if path.hasPrefix("/") {
+        var rpath = path.addingPercentEncoding(withAllowedCharacters: .urlPathAllowed) ?? path
+        if rpath.hasPrefix("/") {
             rpath.remove(at: rpath.startIndex)
         }
-        let url = URL(string: rpath, relativeTo: baseURL) ?? URL(string: path)!
+        let url = URL(string: rpath, relativeTo: baseURL) ?? URL(string: rpath)!
         super.init(url: url, name: name, path: path)
     }
     
@@ -39,8 +39,8 @@ public final class OneDriveFileObject: FileObject {
         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 = resolve(dateString: json["lastModifiedDateTime"] as? String ?? "")
-        self.creationDate = resolve(dateString: json["createdDateTime"] as? String ?? "")
+        self.modifiedDate = Date(rfcString: json["lastModifiedDateTime"] as? String ?? "")
+        self.creationDate = Date(rfcString: json["createdDateTime"] as? String ?? "")
         self.type = (json["folder"] as? String) != nil ? .directory : .regular
         self.id = json["id"] as? String
         self.entryTag = json["eTag"] as? String
@@ -61,20 +61,20 @@ public final class OneDriveFileObject: FileObject {
     /// MIME type of file contents returned by OneDrive server.
     open internal(set) var contentType: String {
         get {
-            return allValues[.mimeType] as? String ?? ""
+            return allValues[.mimeTypeKey] as? String ?? ""
         }
         set {
-            allValues[.mimeType] = newValue
+            allValues[.mimeTypeKey] = newValue
         }
     }
     
     /// HTTP E-Tag, can be used to mark changed files.
     open internal(set) var entryTag: String? {
         get {
-            return allValues[.entryTag] as? String
+            return allValues[.entryTagKey] as? String
         }
         set {
-            allValues[.entryTag] = newValue
+            allValues[.entryTagKey] = newValue
         }
     }
 }
@@ -85,7 +85,7 @@ internal extension OneDriveFileProvider {
         let url = cursor ?? self.url(of: path, modifier: "children")
         var request = URLRequest(url: url)
         request.httpMethod = "GET"
-        request.setValue("Bearer \(credential?.password ?? "")", forHTTPHeaderField: "Authorization")
+        request.set(httpAuthentication: credential, with: .oAuth2)
         let task = session.dataTask(with: request, completionHandler: { (data, response, error) in
             var responseError: FileProviderOneDriveError?
             var files = prevContents
@@ -113,35 +113,8 @@ internal extension OneDriveFileProvider {
         task.resume()
     }
     
-    func upload_simple(_ targetPath: String, data: Data, modifiedDate: Date = Date(), overwrite: Bool, operation: FileOperationType, completionHandler: SimpleCompletionHandler) -> OperationHandle? {
-        if data.count > 100 * 1024 * 1024 {
-            let error = FileProviderOneDriveError(code: .payloadTooLarge, path: targetPath, errorDescription: nil)
-            completionHandler?(error)
-            self.delegateNotify(.create(path: targetPath), error: error)
-            return nil
-        }
-        let queryStr = overwrite ? "" : "?@name.conflictBehavior=fail"
-        let url = self.url(of: targetPath, modifier: "content\(queryStr)")
-        var request = URLRequest(url: url)
-        request.httpMethod = "PUT"
-        request.setValue("Bearer \(credential?.password ?? "")", forHTTPHeaderField: "Authorization")
-        request.setValue("application/octet-stream", forHTTPHeaderField: "Content-Type")
-        request.httpBody = data
-        let task = session.uploadTask(with: request, from: data, 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: targetPath, errorDescription: String(data: data ?? Data(), encoding: .utf8))
-            }
-            completionHandler?(responseError ?? error)
-            self.delegateNotify(operation, error: responseError ?? error)
-        })
-        task.taskDescription = operation.json
-        task.resume()
-        return RemoteOperationHandle(operationType: operation, tasks: [task])
-    }
-    
-    func upload_simple(_ targetPath: String, localFile: URL, modifiedDate: Date = Date(), overwrite: Bool, operation: FileOperationType, completionHandler: SimpleCompletionHandler) -> OperationHandle? {
-        let size = (try? localFile.resourceValues(forKeys: [.fileSizeKey]))?.fileSize ?? -1
+    func upload_simple(_ targetPath: String, data: Data? = nil , localFile: URL? = nil, modifiedDate: Date = Date(), overwrite: Bool, operation: FileOperationType, completionHandler: SimpleCompletionHandler) -> OperationHandle? {
+        let size = data?.count ?? (try? localFile?.resourceValues(forKeys: [.fileSizeKey]))??.fileSize ?? -1
         if size > 100 * 1024 * 1024 {
             let error = FileProviderOneDriveError(code: .payloadTooLarge, path: targetPath, errorDescription: nil)
             completionHandler?(error)
@@ -152,16 +125,26 @@ internal extension OneDriveFileProvider {
         let url = self.url(of: targetPath, modifier: "content\(queryStr)")
         var request = URLRequest(url: url)
         request.httpMethod = "PUT"
-        request.setValue("Bearer \(credential?.password ?? "")", forHTTPHeaderField: "Authorization")
-        request.setValue("application/octet-stream", forHTTPHeaderField: "Content-Type")
-        let task = session.uploadTask(with: request, fromFile: localFile, completionHandler: { (data, response, error) in
+        request.set(httpAuthentication: credential, with: .oAuth2)
+        request.set(contentType: .stream)
+        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: FileProviderOneDriveError?
-            if let code = (response as? HTTPURLResponse)?.statusCode , code >= 300, let rCode = FileProviderHTTPErrorCode(rawValue: code) {
-                responseError = FileProviderOneDriveError(code: rCode, path: targetPath, errorDescription: String(data: data ?? Data(), encoding: .utf8))
+            if let code = (task.response as? HTTPURLResponse)?.statusCode , code >= 300, let rCode = FileProviderHTTPErrorCode(rawValue: code) {
+                // We can't fetch server result from delegate!
+                responseError = FileProviderOneDriveError(code: rCode, path: targetPath, errorDescription: nil)
             }
             completionHandler?(responseError ?? error)
-            self.delegateNotify(operation, error: responseError ?? error)
-        })
+            self?.delegateNotify(.create(path: targetPath), error: responseError ?? error)
+        }
         task.taskDescription = operation.json
         task.resume()
         return RemoteOperationHandle(operationType: operation, tasks: [task])
@@ -173,7 +156,7 @@ internal extension OneDriveFileProvider {
         url = next ?? self.url(of: startPath, modifier: "view.search?q=\(q)")
         var request = URLRequest(url: url)
         request.httpMethod = "GET"
-        request.setValue("Bearer \(credential?.password ?? "")", forHTTPHeaderField: "Authorization")
+        request.set(httpAuthentication: credential, with: .oAuth2)
         
         let task = session.dataTask(with: request, completionHandler: { (data, response, error) in
             var responseError: FileProviderOneDriveError?
@@ -240,14 +223,14 @@ internal extension OneDriveFileProvider {
         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))
+            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 = resolve(dateString: timeTakenStr) {
+        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))
         }

Sources/RemoteSession.swift

@@ -9,41 +9,48 @@
 import Foundation
 
 /// Allows to get progress or cancel an in-progress operation, for remote, `URLSession` based providers.
+/// This class keeps strong reference to tasks.
 open class RemoteOperationHandle: OperationHandle {
     
-    internal var tasks: [Weak<URLSessionTask>]
+    internal var tasks: [URLSessionTask]
     
     open private(set) var operationType: FileOperationType
     
     init(operationType: FileOperationType, tasks: [URLSessionTask]) {
         self.operationType = operationType
-        self.tasks = tasks.map { Weak<URLSessionTask>($0) }
+        self.tasks = tasks
     }
     
     internal func add(task: URLSessionTask) {
-        tasks.append(Weak<URLSessionTask>(task))
+        tasks.append(task)
     }
     
-    private func reape() {
-        self.tasks = tasks.filter { $0.value != nil }
+    internal func reape() {
+        self.tasks = tasks.filter { $0.state != .completed }
     }
     
     open var bytesSoFar: Int64 {
         return tasks.reduce(0) {
-            if let task = $1.value as? URLSessionUploadTask {
+            switch $1 {
+            case let task as URLSessionUploadTask:
                 return $0 + task.countOfBytesSent
-            } else {
-                return $0 + ($1.value?.countOfBytesReceived ?? 0)
+            case let task as FileProviderStreamTask:
+                return $0 + task.countOfBytesSent + task.countOfBytesReceived
+            default:
+                return $0 + $1.countOfBytesReceived
             }
         }
     }
     
     open var totalBytes: Int64 {
         return tasks.reduce(0) {
-            if let task = $1.value as? URLSessionUploadTask {
+            switch $1 {
+            case let task as URLSessionUploadTask:
                 return $0 + task.countOfBytesExpectedToSend
-            } else {
-                return $0 + ($1.value?.countOfBytesExpectedToReceive ?? 0)
+            case let task as FileProviderStreamTask:
+                return $0 + task.countOfBytesExpectedToSend + task.countOfBytesExpectedToReceive
+            default:
+                return $0 + $1.countOfBytesExpectedToReceive
             }
         }
     }
@@ -51,20 +58,22 @@ open class RemoteOperationHandle: OperationHandle {
     open func cancel() -> Bool {
         var canceled = false
         for taskbox in tasks {
-            taskbox.value?.cancel()
+            taskbox.cancel()
             canceled = true
         }
         return canceled
     }
     
     open var inProgress: Bool {
-        return tasks.reduce(false) { $0 || $1.value?.state ?? .canceling == .running }
+        return tasks.reduce(false) { $0 || $1.state == .running }
     }
 }
 
 /// 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
@@ -77,29 +86,107 @@ extension FileProviderHTTPError {
     public var description: String {
         return code.description
     }
+    
+    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
     }
     
     // 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 !(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 json = task.taskDescription?.deserializeJSON(),
@@ -107,12 +194,23 @@ class SessionDelegate: NSObject, URLSessionDataDelegate, URLSessionDownloadDeleg
             return
         }
         
+        switch op {
+        case .create(path: let path):
+            if path.hasSuffix("/") { return }
+        case .modify:
+            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 json = downloadTask.taskDescription?.deserializeJSON(),
@@ -120,14 +218,16 @@ class SessionDelegate: NSObject, URLSessionDataDelegate, URLSessionDownloadDeleg
             return
         }
         
-        fileProvider.delegate?.fileproviderProgress(fileProvider, operation: op, 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) {
+    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) {
+    public func urlSession(_ session: URLSession, didReceive challenge: URLAuthenticationChallenge, completionHandler: @escaping (URLSession.AuthChallengeDisposition, URLCredential?) -> Void) {
         authenticate(didReceive: challenge, completionHandler: completionHandler)
     }
     
@@ -141,6 +241,11 @@ class SessionDelegate: NSObject, URLSessionDataDelegate, URLSessionDownloadDeleg
             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)
+    }
 }
 
 /// HTTP status codes as an enum.

Sources/SMBClient.swift

@@ -11,11 +11,11 @@ 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 receivedResponse(client: SMB2ProtocolClient, response: SMBResponse, for: SMBRequest)
+protocol FileProviderSMBTaskDelegate: class {
+    func receivedResponse(client: FileProviderSMBTask, response: SMBResponse, for: SMBRequest)
 }
 
-class SMB2ProtocolClient: FPSStreamTask {
+class FileProviderSMBTask: FileProviderStreamTask {
     var timeout: TimeInterval = 30
     
     private(set) var lastMessageID: UInt64 = 0
@@ -31,14 +31,14 @@ class SMB2ProtocolClient: FPSStreamTask {
     private(set) var requestStack = [Int: SMBRequest]()
     private(set) var responseStack = [Int: SMBResponse]()
     
-    weak var delegate: SMBProtocolClientDelegate?
+    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
@@ -50,9 +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: self.timeout, 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)
                 })
@@ -73,7 +73,7 @@ class SMB2ProtocolClient: FPSStreamTask {
         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)
             
         })
@@ -85,7 +85,7 @@ class SMB2ProtocolClient: FPSStreamTask {
         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
@@ -96,7 +96,7 @@ 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
@@ -108,7 +108,7 @@ class SMB2ProtocolClient: FPSStreamTask {
 }
 
 // MARK: create and analyse messages
-extension SMB2ProtocolClient {
+extension FileProviderSMBTask {
     func determineSMBVersion(_ data: Data) -> Float {
         let smbverChar: Int8 = Int8(bitPattern: data.first ?? 0)
         let version = 0 - smbverChar

Sources/SMBFileProvider.swift

@@ -15,22 +15,47 @@ class SMBFileProvider: FileProvider, FileProviderMonitor {
     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.appendingPathComponent("")
-        dispatch_queue = DispatchQueue(label: "FileProvider.\(type(of: self).type)", attributes: .concurrent)
+        
+        #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 = "FileProvider.\(type(of: self).type).Operation"
+        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()
     }
@@ -54,11 +79,6 @@ class SMBFileProvider: FileProvider, FileProviderMonitor {
         return nil
     }
     
-    open func create(file fileName: String, at atPath: String, contents data: Data?, completionHandler: SimpleCompletionHandler) -> OperationHandle? {
-        NotImplemented()
-        return nil
-    }
-    
     open func moveItem(path: String, to toPath: String, overwrite: Bool = false, completionHandler: SimpleCompletionHandler) -> OperationHandle? {
         NotImplemented()
         return nil
@@ -94,7 +114,7 @@ class SMBFileProvider: FileProvider, FileProviderMonitor {
         return nil
     }
     
-    open func writeContents(path: String, contents data: Data, atomically: Bool, overwrite: Bool, completionHandler: SimpleCompletionHandler) -> OperationHandle? {
+    open func writeContents(path: String, contents data: Data?, atomically: Bool, overwrite: Bool, completionHandler: SimpleCompletionHandler) -> OperationHandle? {
         NotImplemented()
         return nil
     }
@@ -116,7 +136,7 @@ class SMBFileProvider: FileProvider, FileProviderMonitor {
     }
     
     open func copy(with zone: NSZone? = nil) -> Any {
-        let copy = SMBFileProvider(baseURL: self.baseURL!, credential: self.credential!, afterInitialized: { _ in })!
+        let copy = SMBFileProvider(baseURL: self.baseURL!, credential: self.credential!)!
         copy.currentPath = self.currentPath
         copy.delegate = self.delegate
         copy.fileOperationDelegate = self.fileOperationDelegate

Sources/WebDAVFileProvider.swift

@@ -7,12 +7,13 @@
 //
 
 import Foundation
+import CoreGraphics
 
 /**
  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.net](https://www.box.com/home) 
+ 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
@@ -32,7 +33,12 @@ open class WebDAVFileProvider: FileProviderBasicRemote {
     }
     
     public weak var delegate: FileProviderDelegate?
-    open let credential: URLCredential?
+    public var credentialType: HTTPAuthenticationType = .digest
+    open var credential: URLCredential? {
+        didSet {
+            sessionDelegate?.credential = credential
+        }
+    }
     open private(set) var cache: URLCache?
     public var useCache: Bool
     public var validatingCache: Bool
@@ -40,16 +46,30 @@ open class WebDAVFileProvider: FileProviderBasicRemote {
     fileprivate var _session: URLSession?
     fileprivate var sessionDelegate: SessionDelegate?
     public var session: URLSession {
-        if _session == nil {
-            self.sessionDelegate = SessionDelegate(fileProvider: self, credential: credential)
-            let queue = OperationQueue()
-            //queue.underlyingQueue = dispatch_queue
-            let config = URLSessionConfiguration.default
-            config.urlCache = cache
-            config.requestCachePolicy = .returnCacheDataElseLoad
-            _session = URLSession(configuration: config, delegate: sessionDelegate as URLSessionDownloadDelegate?, delegateQueue: queue)
+        get {
+            if _session == nil {
+                self.sessionDelegate = SessionDelegate(fileProvider: self)
+                let queue = OperationQueue()
+                //queue.underlyingQueue = dispatch_queue
+                let config = URLSessionConfiguration.default
+                config.urlCache = cache
+                config.requestCachePolicy = .returnCacheDataElseLoad
+                _session = URLSession(configuration: config, delegate: sessionDelegate as URLSessionDownloadDelegate?, delegateQueue: 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!)
         }
-        return _session!
     }
     
     /**
@@ -64,18 +84,61 @@ open class WebDAVFileProvider: FileProviderBasicRemote {
         if  !["http", "https"].contains(baseURL.uw_scheme.lowercased()) {
             return nil
         }
-        self.baseURL = baseURL.path.hasSuffix("/") ? baseURL : baseURL.appendingPathComponent("")
+        self.baseURL = (baseURL.absoluteString.hasSuffix("/") ? baseURL : baseURL.appendingPathComponent("")).absoluteURL
         self.currentPath = ""
         self.useCache = false
         self.validatingCache = true
         self.cache = cache
         self.credential = credential
-        dispatch_queue = DispatchQueue(label: "FileProvider.\(type(of: self).type)", attributes: .concurrent)
+        
+        #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 = "FileProvider.\(type(of: self).type).Operation"
+        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,
+                  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 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 {
+        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
     }
     
     deinit {
+        if let sessionuuid = _session?.sessionDescription {
+            removeSessionHandler(for: sessionuuid)
+        }
+        
         if fileProviderCancelTasksOnInvalidating {
             _session?.invalidateAndCancel()
         } else {
@@ -83,14 +146,30 @@ open class WebDAVFileProvider: FileProviderBasicRemote {
         }
     }
     
-    open func contentsOfDirectory(path: String, completionHandler: @escaping ((_ contents: [FileObject], _ error: Error?) -> Void)) {
+    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")
         runDataTask(with: request, operationHandle: RemoteOperationHandle(operationType: opType, tasks: []), completionHandler: { (data, response, error) in
             var responseError: FileProviderWebDavError?
@@ -112,12 +191,28 @@ open class WebDAVFileProvider: FileProviderBasicRemote {
     }
     
     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")
         runDataTask(with: request, completionHandler: { (data, response, error) in
             var responseError: FileProviderWebDavError?
@@ -145,7 +240,8 @@ open class WebDAVFileProvider: FileProviderBasicRemote {
         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")
         runDataTask(with: request, completionHandler: { (data, response, error) in
@@ -167,7 +263,8 @@ open class WebDAVFileProvider: FileProviderBasicRemote {
         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)
         runDataTask(with: request, completionHandler: { (data, response, error) in
             // FIXME: paginating results
@@ -198,7 +295,8 @@ open class WebDAVFileProvider: FileProviderBasicRemote {
         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")
         runDataTask(with: request, completionHandler: { (data, response, error) in
@@ -220,6 +318,7 @@ extension WebDAVFileProvider: FileProviderOperations {
         let url = self.url(of: atPath).appendingPathComponent(folderName, isDirectory: true)
         var request = URLRequest(url: url)
         request.httpMethod = "MKCOL"
+        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) {
@@ -233,28 +332,6 @@ extension WebDAVFileProvider: FileProviderOperations {
         return RemoteOperationHandle(operationType: opType, tasks: [task])
     }
     
-    @discardableResult
-    open func create(file fileName: String, at path: String, contents data: Data?, completionHandler: SimpleCompletionHandler) -> OperationHandle? {
-        let opType = FileOperationType.create(path: (path as NSString).appendingPathComponent(fileName))
-        guard fileOperationDelegate?.fileProvider(self, shouldDoOperation: opType) ?? true == true else {
-            return nil
-        }
-        let url = self.url(of: path).appendingPathComponent(fileName)
-        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, path: path, errorDescription: String(data: data ?? Data(), encoding: .utf8), url: url)
-            }
-            completionHandler?(responseError ?? error)
-            self.delegateNotify(opType, error: responseError ?? error)
-        })
-        task.taskDescription = opType.json
-        task.resume()
-        return RemoteOperationHandle(operationType: opType, tasks: [task])
-    }
-    
     @discardableResult
     open func moveItem(path: String, to toPath: String, overwrite: Bool = false, completionHandler: SimpleCompletionHandler) -> OperationHandle? {
         let opType = FileOperationType.move(source: path, destination: toPath)
@@ -282,7 +359,7 @@ extension WebDAVFileProvider: FileProviderOperations {
         return self.doOperation(operation: opType, completionHandler: completionHandler)
     }
     
-    func doOperation(operation opType: FileOperationType, overwrite: Bool? = nil, completionHandler: SimpleCompletionHandler) -> OperationHandle?  {
+    fileprivate func doOperation(operation opType: FileOperationType, overwrite: Bool? = nil, completionHandler: SimpleCompletionHandler) -> OperationHandle?  {
         let source = opType.source!
         let sourceURL = self.url(of: source)
         var request = URLRequest(url: sourceURL)
@@ -300,6 +377,7 @@ extension WebDAVFileProvider: FileProviderOperations {
             return nil
         }
         
+        request.set(httpAuthentication: credential, with: credentialType)
         if let overwrite = overwrite, !overwrite {
             request.setValue("F", forHTTPHeaderField: "Overwrite")
         }
@@ -330,6 +408,14 @@ extension WebDAVFileProvider: FileProviderOperations {
     
     @discardableResult
     open func copyItem(localFile: URL, to toPath: String, overwrite: Bool, completionHandler: SimpleCompletionHandler) -> OperationHandle? {
+        // 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
@@ -340,43 +426,47 @@ extension WebDAVFileProvider: FileProviderOperations {
             request.setValue("F", forHTTPHeaderField: "Overwrite")
         }
         request.httpMethod = "PUT"
-        let task = session.uploadTask(with: request, fromFile: localFile, completionHandler: { (data, response, error) in
+        request.set(httpAuthentication: credential, with: credentialType)
+        let task = session.uploadTask(with: request, fromFile: localFile)
+        completionHandlersForTasks[session.sessionDescription!]?[task.taskIdentifier] = { [weak self] error in
             var responseError: FileProviderWebDavError?
-            if let code = (response as? HTTPURLResponse)?.statusCode , code >= 300, let rCode = FileProviderHTTPErrorCode(rawValue: code) {
-                responseError = FileProviderWebDavError(code: rCode, path: toPath, errorDescription: String(data: data ?? Data(), encoding: .utf8), url: url)
+            if let code = (task.response as? HTTPURLResponse)?.statusCode , code >= 300, let rCode = FileProviderHTTPErrorCode(rawValue: code) {
+                // We can't fetch server result from delegate!
+                responseError = FileProviderWebDavError(code: rCode, path: toPath, errorDescription: nil, url: url)
             }
             completionHandler?(responseError ?? error)
-            self.delegateNotify(opType, error: responseError ?? error)
-        }) 
+            self?.delegateNotify(.create(path: toPath), error: responseError ?? error)
+        }
         task.taskDescription = opType.json
         task.resume()
         return RemoteOperationHandle(operationType: opType, tasks: [task])
     }
     
     @discardableResult
-    open func copyItem(path: String, toLocalURL: URL, completionHandler: SimpleCompletionHandler) -> OperationHandle? {
-        let opType = FileOperationType.copy(source: path, destination: toLocalURL.absoluteString)
+    open func copyItem(path: String, toLocalURL destURL: URL, completionHandler: SimpleCompletionHandler) -> OperationHandle? {
+        let opType = FileOperationType.copy(source: path, destination: destURL.absoluteString)
         guard fileOperationDelegate?.fileProvider(self, shouldDoOperation: opType) ?? true == true else {
             return nil
         }
         let url = self.url(of: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, path: path, errorDescription: nil, url: url)
+        var request = URLRequest(url: url)
+        request.set(httpAuthentication: credential, with: credentialType)
+        let task = session.downloadTask(with: request)
+        completionHandlersForTasks[session.sessionDescription!]?[task.taskIdentifier] = completionHandler
+        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 serverError : FileProviderWebDavError? = code != nil ? FileProviderWebDavError(code: code!, path: path, errorDescription: code?.description, url: url) : nil
+                completionHandler?(serverError)
+                return
             }
-            if let sourceFileURL = sourceFileURL {
-                do {
-                    try FileManager.default.copyItem(at: sourceFileURL, to: toLocalURL)
-                } catch let e {
-                    completionHandler?(e)
-                    return
-                }
+            do {
+                try FileManager.default.moveItem(at: tempURL, to: destURL)
+                completionHandler?(nil)
+            } catch let e {
+                completionHandler?(e)
             }
-            completionHandler?(responseError ?? error)
-            self.delegateNotify(opType, error: responseError ?? error)
-        }) 
+        }
         task.taskDescription = opType.json
         task.resume()
         return RemoteOperationHandle(operationType: opType, tasks: [task])
@@ -396,25 +486,37 @@ extension WebDAVFileProvider: FileProviderReadWrite {
         let opType = FileOperationType.fetch(path: path)
         let url = self.url(of: path)
         var request = URLRequest(url: url)
-        request.httpMethod = "GET"
-        if length > 0 {
-            request.setValue("bytes=\(offset)-\(offset + length - 1)", forHTTPHeaderField: "Range")
-        } else if offset > 0 && length < 0 {
-            request.setValue("bytes=\(offset)-", forHTTPHeaderField: "Range")
+        request.set(httpAuthentication: credential, with: credentialType)
+        request.set(rangeWithOffset: offset, length: length)
+        
+        let task = session.downloadTask(with: request)
+        let handle = RemoteOperationHandle(operationType: opType, tasks: [task])
+        completionHandlersForTasks[session.sessionDescription!]?[task.taskIdentifier] = { error in
+            completionHandler(nil, error)
         }
-        let handle = RemoteOperationHandle(operationType: opType, tasks: [])
-        runDataTask(with: request, operationHandle: handle, 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)
+        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 serverError : FileProviderWebDavError? = code != nil ? FileProviderWebDavError(code: code!, path: path, errorDescription: code?.description, url: url) : nil
+                completionHandler(nil, serverError)
+                return
             }
-            completionHandler(data, responseError ?? error)
-        })
+            do {
+                let data = try Data(contentsOf: tempURL)
+                self.dispatch_queue.async {
+                    completionHandler(data, nil)
+                }
+            } catch let e {
+                completionHandler(nil, e)
+            }
+        }
+        task.taskDescription = opType.json
+        task.resume()
         return handle
     }
     
     @discardableResult
-    open func writeContents(path: String, contents data: Data, atomically: Bool, overwrite: Bool, completionHandler: SimpleCompletionHandler) -> OperationHandle? {
+    open func writeContents(path: String, contents data: Data?, atomically: Bool, overwrite: Bool, completionHandler: SimpleCompletionHandler) -> OperationHandle? {
         let opType = FileOperationType.modify(path: path)
         guard fileOperationDelegate?.fileProvider(self, shouldDoOperation: opType) ?? true == true else {
             return nil
@@ -423,25 +525,20 @@ extension WebDAVFileProvider: FileProviderReadWrite {
         let url = atomically ? self.url(of: path).appendingPathExtension("tmp") : self.url(of: path)
         var request = URLRequest(url: url)
         request.httpMethod = "PUT"
+        request.set(httpAuthentication: credential, with: credentialType)
         if !overwrite {
             request.setValue("F", forHTTPHeaderField: "Overwrite")
         }
-        let task = session.uploadTask(with: request, from: data, completionHandler: { (data, response, error) in
+        let task = session.uploadTask(with: request, from: data ?? Data())
+        completionHandlersForTasks[session.sessionDescription!]?[task.taskIdentifier] = { [weak self] 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: self.url(of: path))
+            if let code = (task.response as? HTTPURLResponse)?.statusCode , code >= 300, let rCode = FileProviderHTTPErrorCode(rawValue: code) {
+                // We can't fetch server result from delegate!
+                responseError = FileProviderWebDavError(code: rCode, path: path, errorDescription: nil, url: url)
             }
-            defer {
-                self.delegateNotify(opType, error: responseError ?? error)
-            }
-            if let error = error {
-                completionHandler?(error)
-                return
-            }
-            if atomically {
-                self.moveItem(path: (path as NSString).appendingPathExtension("tmp")!, to: path, completionHandler: completionHandler)
-            }
-        }) 
+            completionHandler?(responseError ?? error)
+            self?.delegateNotify(opType, error: responseError ?? error)
+        }
         task.taskDescription = opType.json
         task.resume()
         return RemoteOperationHandle(operationType: opType, tasks: [task])
@@ -463,18 +560,88 @@ extension WebDAVFileProvider: FileProviderReadWrite {
     // TODO: implements methods for lock mechanism
 }
 
-extension WebDAVFileProvider: FileProvider {
-    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
+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)
+        })
+    }
+}
+
+extension WebDAVFileProvider: FileProvider { }
+
 // MARK: WEBDAV XML response implementation
 
 internal extension WebDAVFileProvider {
@@ -497,12 +664,9 @@ struct DavResponse {
     
     init? (_ node: AEXMLElement, baseURL: URL?) {
         
-        func removeSlash(_ str: String) -> String {
-            if str.hasPrefix("/") {
-                return str.substring(from: str.index(after: str.startIndex))
-            } else {
-                return str
-            }
+        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
         }
         
         // find node names with namespace
@@ -524,9 +688,14 @@ struct DavResponse {
         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)?.absoluteString ?? hrefString
-        let relativePath = hrefAbsolute.replacingOccurrences(of: baseURL?.absoluteString ?? "", with: "", options: .anchored, range: nil)
-        let hrefURL = URL(string: removeSlash(relativePath), relativeTo: baseURL) ?? baseURL
+        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
+        }
+        let hrefURL = URL(string: standardizePath(relativePath), relativeTo: baseURL) ?? baseURL
         
         guard let href = hrefURL?.standardized else { return nil }
         
@@ -588,13 +757,13 @@ struct DavResponse {
 public final class WebDavFileObject: FileObject {
     internal init(_ davResponse: DavResponse) {
         let href = davResponse.href
-        let name = davResponse.prop["displayname"] ?? (davResponse.hrefString.removingPercentEncoding! as NSString).lastPathComponent
+        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 = resolve(dateString: davResponse.prop["creationdate"] ?? "")
-        self.modifiedDate = resolve(dateString: davResponse.prop["getlastmodified"] ?? "")
+        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
@@ -604,22 +773,54 @@ public final class WebDavFileObject: FileObject {
     /// MIME type of the file.
     open internal(set) var contentType: String {
         get {
-            return allValues[.mimeType] as? String ?? ""
+            return allValues[.mimeTypeKey] as? String ?? ""
         }
         set {
-            allValues[.mimeType] = newValue
+            allValues[.mimeTypeKey] = newValue
         }
     }
     
     /// HTTP E-Tag, can be used to mark changed files.
     open internal(set) var entryTag: String? {
         get {
-            return allValues[.entryTag] as? String
+            return allValues[.entryTagKey] as? String
         }
         set {
-            allValues[.entryTag] = newValue
+            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.