Fixed currentPath docs, delegateNotify method default error arg

Fixed FTP crash on rucursive remove
Removed FoundationErrorEnum, Refactoed delegate progress routine
2017-08-29 01:40:15 +04:30 · 2017-08-28 00:06:02 +04:30 · 2017-08-27 13:48:29 +04:30 · 2017-08-24 15:08:22 +04:30 · 2017-08-24 08:36:11 +04:30 · 2017-08-23 23:21:17 +04:30
19 changed files with 1889 additions and 1766 deletions
@@ -16,7 +16,7 @@ Pod::Spec.new do |s|
  #

  s.name         = "FilesProvider"
-  s.version      = "0.19.0"
+  s.version      = "0.20.1"
  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.
@@ -38,6 +38,12 @@
 		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 */; };
+		793CCE2A1F4B8C5C00BC8288 /* FoundationExtensions.swift in Sources */ = {isa = PBXBuildFile; fileRef = 793CCE291F4B8C5C00BC8288 /* FoundationExtensions.swift */; };
+		793CCE2B1F4B8C5C00BC8288 /* FoundationExtensions.swift in Sources */ = {isa = PBXBuildFile; fileRef = 793CCE291F4B8C5C00BC8288 /* FoundationExtensions.swift */; };
+		793CCE2C1F4B8C5C00BC8288 /* FoundationExtensions.swift in Sources */ = {isa = PBXBuildFile; fileRef = 793CCE291F4B8C5C00BC8288 /* FoundationExtensions.swift */; };
+		793CCE2E1F4B8C7B00BC8288 /* HashMAC.swift in Sources */ = {isa = PBXBuildFile; fileRef = 793CCE2D1F4B8C7B00BC8288 /* HashMAC.swift */; };
+		793CCE2F1F4B8C7B00BC8288 /* HashMAC.swift in Sources */ = {isa = PBXBuildFile; fileRef = 793CCE2D1F4B8C7B00BC8288 /* HashMAC.swift */; };
+		793CCE301F4B8C7B00BC8288 /* HashMAC.swift in Sources */ = {isa = PBXBuildFile; fileRef = 793CCE2D1F4B8C7B00BC8288 /* HashMAC.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 */; };
@@ -50,9 +56,9 @@
 		794C220E1D591A4B00EC49B8 /* SMB2QueryTypes.swift in Sources */ = {isa = PBXBuildFile; fileRef = 794C220D1D591A4B00EC49B8 /* SMB2QueryTypes.swift */; };
 		794C220F1D591A4B00EC49B8 /* SMB2QueryTypes.swift in Sources */ = {isa = PBXBuildFile; fileRef = 794C220D1D591A4B00EC49B8 /* SMB2QueryTypes.swift */; };
 		794C22101D591A4B00EC49B8 /* SMB2QueryTypes.swift in Sources */ = {isa = PBXBuildFile; fileRef = 794C220D1D591A4B00EC49B8 /* SMB2QueryTypes.swift */; };
-		796807551E7BF17E00BBB87B /* FileProviderExtensions.swift in Sources */ = {isa = PBXBuildFile; fileRef = 796807541E7BF17E00BBB87B /* FileProviderExtensions.swift */; };
-		796807561E7BF17E00BBB87B /* FileProviderExtensions.swift in Sources */ = {isa = PBXBuildFile; fileRef = 796807541E7BF17E00BBB87B /* FileProviderExtensions.swift */; };
-		796807571E7BF17E00BBB87B /* FileProviderExtensions.swift in Sources */ = {isa = PBXBuildFile; fileRef = 796807541E7BF17E00BBB87B /* FileProviderExtensions.swift */; };
+		7958155A1F478ED9003344DD /* HTTPFileProvider.swift in Sources */ = {isa = PBXBuildFile; fileRef = 795815591F478ED9003344DD /* HTTPFileProvider.swift */; };
+		7958155B1F478ED9003344DD /* HTTPFileProvider.swift in Sources */ = {isa = PBXBuildFile; fileRef = 795815591F478ED9003344DD /* HTTPFileProvider.swift */; };
+		7958155C1F478ED9003344DD /* HTTPFileProvider.swift in Sources */ = {isa = PBXBuildFile; fileRef = 795815591F478ED9003344DD /* HTTPFileProvider.swift */; };
 		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 */; };
@@ -140,11 +146,13 @@
 		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>"; };
+		793CCE291F4B8C5C00BC8288 /* FoundationExtensions.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = FoundationExtensions.swift; sourceTree = "<group>"; };
+		793CCE2D1F4B8C7B00BC8288 /* HashMAC.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = HashMAC.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>"; };
+		795815591F478ED9003344DD /* HTTPFileProvider.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = HTTPFileProvider.swift; sourceTree = "<group>"; };
 		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; };
@@ -255,6 +263,15 @@
 			path = AEXML;
 			sourceTree = "<group>";
 		};
+		793CCE281F4B8C3600BC8288 /* Extensions */ = {
+			isa = PBXGroup;
+			children = (
+				793CCE291F4B8C5C00BC8288 /* FoundationExtensions.swift */,
+				793CCE2D1F4B8C7B00BC8288 /* HashMAC.swift */,
+			);
+			path = Extensions;
+			sourceTree = "<group>";
+		};
 		7993965B1D48B7BF00086753 = {
 			isa = PBXGroup;
 			children = (
@@ -290,26 +307,27 @@
 			isa = PBXGroup;
 			children = (
 				7924B18B1D89DAE000589DB7 /* AEXML */,
+				793CCE281F4B8C3600BC8288 /* Extensions */,
 				799396991D48C02300086753 /* SMBTypes */,
 				799396941D48C02300086753 /* FileProvider.h */,
 				799396951D48C02300086753 /* FileProvider.swift */,
-				796807541E7BF17E00BBB87B /* FileProviderExtensions.swift */,
 				79F5745A1DFDB10A00179ABF /* FileObject.swift */,
 				799396961D48C02300086753 /* LocalFileProvider.swift */,
 				792572401DF23BDA006A1526 /* LocalHelper.swift */,
 				79480FF51E3ABDD0007E7275 /* CloudFileProvider.swift */,
 				79BD638B1E2CC2300035128C /* ExtendedLocalFileProvider.swift */,
+				7924B1A81D89F79200589DB7 /* FPSStreamTask.swift */,
 				7902C0851D61B56D00564440 /* RemoteSession.swift */,
+				795815591F478ED9003344DD /* HTTPFileProvider.swift */,
 				799396931D48C02300086753 /* DropboxFileProvider.swift */,
 				794C21FD1D58912A00EC49B8 /* DropboxHelper.swift */,
-				7936BC111E880F5700A6C81C /* FTPFileProvider.swift */,
-				798654321E8874BC002FA550 /* FTPHelper.swift */,
 				79BD63C31E2D17880035128C /* OneDriveFileProvider.swift */,
 				79BD63C41E2D17880035128C /* OneDriveHelper.swift */,
-				7924B1A81D89F79200589DB7 /* FPSStreamTask.swift */,
+				799396A61D48C02300086753 /* WebDAVFileProvider.swift */,
+				7936BC111E880F5700A6C81C /* FTPFileProvider.swift */,
+				798654321E8874BC002FA550 /* FTPHelper.swift */,
 				799396971D48C02300086753 /* SMBClient.swift */,
 				799396981D48C02300086753 /* SMBFileProvider.swift */,
-				799396A61D48C02300086753 /* WebDAVFileProvider.swift */,
 			);
 			path = Sources;
 			sourceTree = "<group>";
@@ -490,7 +508,6 @@
 			isa = PBXSourcesBuildPhase;
 			buildActionMask = 2147483647;
 			files = (
-				796807551E7BF17E00BBB87B /* FileProviderExtensions.swift in Sources */,
 				799396B31D48C02300086753 /* LocalFileProvider.swift in Sources */,
 				799396D41D48C02300086753 /* SMB2Tree.swift in Sources */,
 				7924B1A21D89DAE000589DB7 /* Options.swift in Sources */,
@@ -502,6 +519,7 @@
 				7924B1991D89DAE000589DB7 /* Element.swift in Sources */,
 				799396C81D48C02300086753 /* SMB2IOCtl.swift in Sources */,
 				799396D71D48C02300086753 /* SMB2Types.swift in Sources */,
+				7958155A1F478ED9003344DD /* HTTPFileProvider.swift in Sources */,
 				798654331E8874BC002FA550 /* FTPHelper.swift in Sources */,
 				7924B1B21D89FCDA00589DB7 /* FPSStreamTask.swift in Sources */,
 				799396C51D48C02300086753 /* SMB2FileOperation.swift in Sources */,
@@ -519,10 +537,12 @@
 				799396E01D48C02300086753 /* WebDAVFileProvider.swift in Sources */,
 				799396DA1D48C02300086753 /* SMBErrorType.swift in Sources */,
 				799396C21D48C02300086753 /* SMB2FileHandle.swift in Sources */,
+				793CCE2E1F4B8C7B00BC8288 /* HashMAC.swift in Sources */,
 				799396CB1D48C02300086753 /* SMB2Query.swift in Sources */,
 				799396AA1D48C02300086753 /* DropboxFileProvider.swift in Sources */,
 				79BD638C1E2CC2300035128C /* ExtendedLocalFileProvider.swift in Sources */,
 				7924B1B31D89FD6400589DB7 /* SMBClient.swift in Sources */,
+				793CCE2A1F4B8C5C00BC8288 /* FoundationExtensions.swift in Sources */,
 				7924B1A51D89DAE000589DB7 /* Parser.swift in Sources */,
 				799396B01D48C02300086753 /* FileProvider.swift in Sources */,
 				7924B19C1D89DAE000589DB7 /* Error.swift in Sources */,
@@ -533,7 +553,6 @@
 			isa = PBXSourcesBuildPhase;
 			buildActionMask = 2147483647;
 			files = (
-				796807561E7BF17E00BBB87B /* FileProviderExtensions.swift in Sources */,
 				799396B41D48C02300086753 /* LocalFileProvider.swift in Sources */,
 				799396D51D48C02300086753 /* SMB2Tree.swift in Sources */,
 				7924B1A31D89DAE000589DB7 /* Options.swift in Sources */,
@@ -545,6 +564,7 @@
 				7924B1B01D89F7DE00589DB7 /* FPSStreamTask.swift in Sources */,
 				7924B19A1D89DAE000589DB7 /* Element.swift in Sources */,
 				799396C91D48C02300086753 /* SMB2IOCtl.swift in Sources */,
+				7958155B1F478ED9003344DD /* HTTPFileProvider.swift in Sources */,
 				79F4678B1E8B80F200C91A85 /* FTPHelper.swift in Sources */,
 				799396D81D48C02300086753 /* SMB2Types.swift in Sources */,
 				799396C61D48C02300086753 /* SMB2FileOperation.swift in Sources */,
@@ -562,10 +582,12 @@
 				799396E11D48C02300086753 /* WebDAVFileProvider.swift in Sources */,
 				799396DB1D48C02300086753 /* SMBErrorType.swift in Sources */,
 				799396C31D48C02300086753 /* SMB2FileHandle.swift in Sources */,
+				793CCE2F1F4B8C7B00BC8288 /* HashMAC.swift in Sources */,
 				799396CC1D48C02300086753 /* SMB2Query.swift in Sources */,
 				7924B1AD1D89F7D800589DB7 /* SMBClient.swift in Sources */,
 				79BD638D1E2CC2300035128C /* ExtendedLocalFileProvider.swift in Sources */,
 				799396AB1D48C02300086753 /* DropboxFileProvider.swift in Sources */,
+				793CCE2B1F4B8C5C00BC8288 /* FoundationExtensions.swift in Sources */,
 				7924B1A61D89DAE000589DB7 /* Parser.swift in Sources */,
 				799396B11D48C02300086753 /* FileProvider.swift in Sources */,
 				7924B19D1D89DAE000589DB7 /* Error.swift in Sources */,
@@ -576,7 +598,6 @@
 			isa = PBXSourcesBuildPhase;
 			buildActionMask = 2147483647;
 			files = (
-				796807571E7BF17E00BBB87B /* FileProviderExtensions.swift in Sources */,
 				799396B51D48C02300086753 /* LocalFileProvider.swift in Sources */,
 				799396D61D48C02300086753 /* SMB2Tree.swift in Sources */,
 				7924B1A41D89DAE000589DB7 /* Options.swift in Sources */,
@@ -588,6 +609,7 @@
 				7924B1B11D89F7DF00589DB7 /* FPSStreamTask.swift in Sources */,
 				7924B19B1D89DAE000589DB7 /* Element.swift in Sources */,
 				799396CA1D48C02300086753 /* SMB2IOCtl.swift in Sources */,
+				7958155C1F478ED9003344DD /* HTTPFileProvider.swift in Sources */,
 				79F4678C1E8B80F200C91A85 /* FTPHelper.swift in Sources */,
 				799396D91D48C02300086753 /* SMB2Types.swift in Sources */,
 				799396C71D48C02300086753 /* SMB2FileOperation.swift in Sources */,
@@ -605,10 +627,12 @@
 				799396E21D48C02300086753 /* WebDAVFileProvider.swift in Sources */,
 				799396DC1D48C02300086753 /* SMBErrorType.swift in Sources */,
 				799396C41D48C02300086753 /* SMB2FileHandle.swift in Sources */,
+				793CCE301F4B8C7B00BC8288 /* HashMAC.swift in Sources */,
 				799396CD1D48C02300086753 /* SMB2Query.swift in Sources */,
 				7924B1AE1D89F7D900589DB7 /* SMBClient.swift in Sources */,
 				79BD638E1E2CC2300035128C /* ExtendedLocalFileProvider.swift in Sources */,
 				799396AC1D48C02300086753 /* DropboxFileProvider.swift in Sources */,
+				793CCE2C1F4B8C5C00BC8288 /* FoundationExtensions.swift in Sources */,
 				7924B1A71D89DAE000589DB7 /* Parser.swift in Sources */,
 				799396B21D48C02300086753 /* FileProvider.swift in Sources */,
 				7924B19E1D89DAE000589DB7 /* Error.swift in Sources */,
@@ -621,7 +645,7 @@
 		799396601D48B7BF00086753 /* Debug */ = {
 			isa = XCBuildConfiguration;
 			buildSettings = {
-				BUNDLE_VERSION_STRING = 0.19.0;
+				BUNDLE_VERSION_STRING = 0.20.1;
 				CLANG_WARN_BOOL_CONVERSION = YES;
 				CLANG_WARN_CONSTANT_CONVERSION = YES;
 				CLANG_WARN_EMPTY_BODY = YES;
@@ -653,7 +677,7 @@
 		799396611D48B7BF00086753 /* Release */ = {
 			isa = XCBuildConfiguration;
 			buildSettings = {
-				BUNDLE_VERSION_STRING = 0.19.0;
+				BUNDLE_VERSION_STRING = 0.20.1;
 				CLANG_WARN_BOOL_CONVERSION = YES;
 				CLANG_WARN_CONSTANT_CONVERSION = YES;
 				CLANG_WARN_EMPTY_BODY = YES;
@@ -41,8 +41,8 @@ All functions do async calls and it wont block your main thread.
    * For now it has limitation in uploading files up to 150MB.
 - [x] **OneDriveFileProvider** A wrapper around OneDrive REST API, works with `onedrive.com` and compatible (business) servers.
    * For now it has limitation in uploading files up to 100MB.
- [ ] **GoogleFileProvider** A wrapper around Goodle Drive REST API.
 - [ ] **AmazonS3FileProvider** Amazon storage backend. Used by many sites.
+- [ ] **GoogleFileProvider** A wrapper around Goodle Drive REST API.
 - [ ] **SMBFileProvider** SMB2/3 introduced in 2006, which is a file and printer sharing protocol originated from Microsoft Windows and now is replacing AFP protocol on macOS.
    * Data types and some basic functions are implemented but *main interface is not implemented yet!*.
    * SMBv1/CIFS is insecure, deprecated and kinda tricky to be implemented due to strict memory allignment in Swift.
@@ -155,7 +155,7 @@ let credential = URLCredential(user: "user", password: "pass", persistence: .per
 let webdavProvider = WebDAVFileProvider(baseURL: URL(string: "http://www.example.com/dav")!, credential: credential)
 ```

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

 * For Dropbox & OneDrive, user is clientID and password is Token which both must be retrieved via [OAuth2 API of Dropbox](https://www.dropbox.com/developers/reference/oauth-guide). There are libraries like [p2/OAuth2](https://github.com/p2/OAuth2) or [OAuthSwift](https://github.com/OAuthSwift/OAuthSwift) which can facilate the procedure to retrieve token. The latter is easier to use and prefered.
 	
@@ -415,12 +415,12 @@ You can monitor updates in some file system (Local and SMB2), there is three met

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

 * **Please note** in LocalFileProvider it will also monitor changes in subfolders. This behaviour can varies according to file system specification.
@@ -52,7 +52,7 @@ open class CloudFileProvider: LocalFileProvider, FileProviderSharing {
     - Parameter scope: Use `.documents` (default) to put documents that the user is allowed to access inside a Documents subdirectory. Otherwise use `.data` to store user-related data files that your app needs to share but that are not files you want the user to manipulate directly.
    */
    public init? (containerId: String?, scope: UbiquitousScope = .documents) {
-        assert(!CloudFileProvider.asserting || !Thread.isMainThread, "LocalFileProvider.init(containerId:) is not recommended to be executed on Main Thread.")
+        assert(!(CloudFileProvider.asserting && Thread.isMainThread), "CloudFileProvider.init(containerId:) is not recommended to be executed on Main Thread.")
        guard FileManager.default.ubiquityIdentityToken != nil else {
            return nil
        }
@@ -118,7 +118,7 @@ open class CloudFileProvider: LocalFileProvider, FileProviderSharing {
     
     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 path: path to target directory. If empty, root will be iterated.
     - 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.
@@ -187,7 +187,7 @@ open class CloudFileProvider: LocalFileProvider, FileProviderSharing {
     
     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 path: path to target directory. If empty, attributes of root will be returned.
     - 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.
@@ -286,6 +286,7 @@ open class CloudFileProvider: LocalFileProvider, FileProviderSharing {
        
        dispatch_queue.async {
            let pathURL = self.url(of: path)
+            progress.setUserInfoObject(pathURL, forKey: .fileURLKey)
            let mdquery = NSMetadataQuery()
            mdquery.predicate = NSPredicate(format: "(%K BEGINSWITH %@) && (\(updateQueryKeys(query).predicateFormat))", NSMetadataItemPathKey, pathURL.path)
            mdquery.searchScopes = [self.scope.rawValue]
@@ -378,55 +379,6 @@ open class CloudFileProvider: LocalFileProvider, FileProviderSharing {
        }
    }
    
-    /**
-     Creates a new directory at the specified path asynchronously.
-     This will create any necessary intermediate directories.
-     
-     - Parameters:
-       - folder: Directory name.
-       - at: Parent path of new directory.
-       - completionHandler: If an error parameter was provided, a presentable `Error` will be returned.
-     - Returns: A `Progress` object to get progress or cancel progress. Doesn't work on `CloudFileProvider`.
-     */
-    @discardableResult
-    open override func create(folder folderName: String, at atPath: String, completionHandler: SimpleCompletionHandler) -> Progress? {
-        return super.create(folder: folderName, at: atPath, completionHandler: completionHandler)
-    }
-    
-    /**
-     Moves a file or directory from `path` to designated path asynchronously.
-     When you want move a file, destination path should also consists of file name.
-     Either a new name or the old one.
-     
-     - Parameters:
-       - path: original file or directory path.
-       - to: destination path of file or directory, including file/directory name.
-       - overwrite: Destination file should be overwritten if file is already exists. **Default** is `false`.
-       - completionHandler: If an error parameter was provided, a presentable `Error` will be returned.
-     - Returns: A `Progress` object to get progress or cancel progress. Doesn't work on `CloudFileProvider`.
-     */
-    @discardableResult
-    open override func moveItem(path: String, to toPath: String, overwrite: Bool = false, completionHandler: SimpleCompletionHandler) -> Progress? {
-        return super.moveItem(path: path, to: toPath, overwrite: overwrite, completionHandler: completionHandler)
-    }
-    
-    /**
-     Copies a file or directory from `path` to designated path asynchronously.
-     When want copy a file, destination path should also consists of file name.
-     Either a new name or the old one.
-     
-     - Parameters:
-       - path: original file or directory path.
-       - to: destination path of file or directory, including file/directory name.
-       - overwrite: Destination file should be overwritten if file is already exists. **Default** is `false`.
-       - completionHandler: If an error parameter was provided, a presentable `Error` will be returned.
-     - Returns: A `Progress` object to get progress or cancel progress. Doesn't work on `CloudFileProvider`.
-     */
-    @discardableResult
-    open override func copyItem(path: String, to toPath: String, overwrite: Bool = false, completionHandler: SimpleCompletionHandler) -> Progress? {
-        return super.copyItem(path: path, to: toPath, overwrite: overwrite, completionHandler: completionHandler)
-    }
-    
    /**
     Removes the file or directory at the specified path.
     
@@ -458,13 +410,14 @@ open class CloudFileProvider: LocalFileProvider, FileProviderSharing {
    @discardableResult
    open override func copyItem(localFile: URL, to toPath: String, overwrite: Bool, completionHandler: SimpleCompletionHandler) -> Progress? {
        // TODO: Make use of overwrite parameter
-        let opType = FileOperationType.copy(source: localFile.absoluteString, destination: toPath)
+        let operation = FileOperationType.copy(source: localFile.absoluteString, destination: toPath)
        let progress = Progress(parent: nil, userInfo: nil)
-        progress.setUserInfoObject(opType, forKey: .fileProvderOperationTypeKey)
+        progress.setUserInfoObject(operation, forKey: .fileProvderOperationTypeKey)
        progress.kind = .file
        progress.isCancellable = false
+        progress.setUserInfoObject(localFile, forKey: .fileURLKey)
        progress.setUserInfoObject(Progress.FileOperationKind.downloading, forKey: .fileOperationKindKey)
-        monitorFile(path: toPath, opType: opType, progress: progress)
+        monitorFile(path: toPath, operation: operation, progress: progress)
        operation_queue.addOperation {
            let tempFolder: URL
            if #available(iOS 10.0, macOS 10.12, tvOS 10.0, *) {
@@ -479,17 +432,13 @@ open class CloudFileProvider: LocalFileProvider, FileProviderSharing {
                let toUrl = self.url(of: toPath)
                try self.opFileManager.setUbiquitous(true, itemAt: tmpFile, destinationURL: toUrl)
                completionHandler?(nil)
-                DispatchQueue.main.async(execute: {
-                    self.delegate?.fileproviderSucceed(self, operation: opType)
-                })
+                self.delegateNotify(operation)
            } catch let e {
                if self.opFileManager.fileExists(atPath: tmpFile.path) {
                    try? self.opFileManager.removeItem(at: tmpFile)
                }
                completionHandler?(e)
-                DispatchQueue.main.async(execute: {
-                    self.delegate?.fileproviderFailed(self, operation: opType)
-                })
+                self.delegateNotify(operation, error: e)
            }
        }
        return progress
@@ -507,20 +456,19 @@ open class CloudFileProvider: LocalFileProvider, FileProviderSharing {
     */
    @discardableResult
    open override func copyItem(path: String, toLocalURL: URL, completionHandler: SimpleCompletionHandler) -> Progress? {
-        let opType = FileOperationType.copy(source: path, destination: toLocalURL.absoluteString)
+        let operation = FileOperationType.copy(source: path, destination: toLocalURL.absoluteString)
        let progress = Progress(parent: nil, userInfo: nil)
-        progress.setUserInfoObject(opType, forKey: .fileProvderOperationTypeKey)
+        progress.setUserInfoObject(operation, forKey: .fileProvderOperationTypeKey)
        progress.kind = .file
        progress.isCancellable = false
+        progress.setUserInfoObject(self.url(of: path), forKey: .fileURLKey)
        progress.setUserInfoObject(Progress.FileOperationKind.downloading, forKey: .fileOperationKindKey)
-        monitorFile(path: path, opType: opType, progress: progress)
+        monitorFile(path: path, operation: operation, progress: progress)
        do {
            try self.opFileManager.startDownloadingUbiquitousItem(at: self.url(of: path))
        } catch let e {
            completionHandler?(e)
-            DispatchQueue.main.async(execute: {
-                self.delegate?.fileproviderFailed(self, operation: opType)
-            })
+            self.delegateNotify(operation, error: e)
            return nil
        }
        let _ = super.copyItem(path: path, toLocalURL: toLocalURL, completionHandler: completionHandler)
@@ -544,8 +492,9 @@ open class CloudFileProvider: LocalFileProvider, FileProviderSharing {
        let progress = Progress(parent: nil, userInfo: nil)
        progress.setUserInfoObject(operation, forKey: .fileProvderOperationTypeKey)
        progress.kind = .file
+        progress.setUserInfoObject(self.url(of: path), forKey: .fileURLKey)
        progress.setUserInfoObject(Progress.FileOperationKind.downloading, forKey: .fileOperationKindKey)
-        monitorFile(path: path, opType: operation, progress: progress)
+        monitorFile(path: path, operation: operation, progress: progress)
        _ = super.contents(path: path, completionHandler: completionHandler)
        return progress
    }
@@ -569,8 +518,9 @@ open class CloudFileProvider: LocalFileProvider, FileProviderSharing {
        let progress = Progress(parent: nil, userInfo: nil)
        progress.setUserInfoObject(operation, forKey: .fileProvderOperationTypeKey)
        progress.kind = .file
+        progress.setUserInfoObject(self.url(of: path), forKey: .fileURLKey)
        progress.setUserInfoObject(Progress.FileOperationKind.downloading, forKey: .fileOperationKindKey)
-        monitorFile(path: path, opType: operation, progress: progress)
+        monitorFile(path: path, operation: operation, progress: progress)
        _ = super.contents(path: path, offset: offset, length: length, completionHandler: completionHandler)
        return progress
    }
@@ -592,8 +542,9 @@ open class CloudFileProvider: LocalFileProvider, FileProviderSharing {
        let progress = Progress(parent: nil, userInfo: nil)
        progress.setUserInfoObject(operation, forKey: .fileProvderOperationTypeKey)
        progress.kind = .file
+        progress.setUserInfoObject(self.url(of: path), forKey: .fileURLKey)
        progress.setUserInfoObject(Progress.FileOperationKind.downloading, forKey: .fileOperationKindKey)
-        monitorFile(path: path, opType: operation, progress: progress)
+        monitorFile(path: path, operation: operation, progress: progress)
        _ = super.writeContents(path: path, contents: data, atomically: atomically, overwrite: overwrite, completionHandler: completionHandler)
        return progress
    }
@@ -680,7 +631,7 @@ open class CloudFileProvider: LocalFileProvider, FileProviderSharing {
        return file
    }
    
-    func monitorFile(path: String, opType: FileOperationType, progress: Progress?) {
+    fileprivate func monitorFile(path: String, operation: FileOperationType, progress: Progress?) {
        dispatch_queue.async {
            let pathURL = self.url(of: path)
            let size = pathURL.fileSize
@@ -704,21 +655,15 @@ open class CloudFileProvider: LocalFileProvider, FileProviderSharing {
                let uploaded = item.value(forAttribute: NSMetadataUbiquitousItemPercentUploadedKey) as? Double ?? 0
                if (downloaded == 0 || downloaded == 100) && (uploaded > 0 && uploaded < 100) {
                    progress?.completedUnitCount = Int64(uploaded / 100 * Double(progress?.totalUnitCount ?? 0))
-                    DispatchQueue.main.async {
-                        self.delegate?.fileproviderProgress(self, operation: opType, progress: Float(uploaded / 100))
-                    }
+                    self.delegateNotify(operation, progress: uploaded / 100)
                } else if (uploaded == 0 || uploaded == 100) && (downloaded > 0 && downloaded < 100) {
                    progress?.completedUnitCount = Int64(downloaded / 100 * Double(progress?.totalUnitCount ?? 0))
-                    DispatchQueue.main.async {
-                        self.delegate?.fileproviderProgress(self, operation: opType, progress: Float(downloaded / 100))
-                    }
+                    self.delegateNotify(operation, progress: downloaded / 100)
                } else if uploaded == 100 || downloaded == 100 {
                    progress?.completedUnitCount = progress?.totalUnitCount ?? 0
                    query.stop()
                    NotificationCenter.default.removeObserver(updateObserver!)
-                    DispatchQueue.main.async {
-                        self.delegate?.fileproviderSucceed(self, operation: opType)
-                    }
+                    self.delegateNotify(operation)
                }
                
                query.enableUpdates()
@@ -731,20 +676,6 @@ open class CloudFileProvider: LocalFileProvider, FileProviderSharing {
        }
    }
    
-    /// 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.
-    open func evictItem(path: String, completionHandler: SimpleCompletionHandler) {
-        operation_queue.addOperation {
-            do {
-                try self.opFileManager.evictUbiquitousItem(at: self.url(of: path))
-                completionHandler?(nil)
-            } catch let e {
-                completionHandler?(e)
-            }
-        }
-    }
-    
    open func publicLink(to path: String, completionHandler: @escaping ((_ link: URL?, _ attribute: FileObject?, _ expiration: Date?, _ error: Error?) -> Void)) {
        operation_queue.addOperation {
            do {
@@ -760,6 +691,35 @@ open class CloudFileProvider: LocalFileProvider, FileProviderSharing {
            }
        }
    }
+    
+    /// Removes local copy of file, but spares cloud copy.
+    /// - Parameter path: Path of file or directory to be removed from local
+    /// - Parameter completionHandler: If an error parameter was provided, a presentable `Error` will be returned.
+    open func evictItem(path: String, completionHandler: SimpleCompletionHandler) {
+        operation_queue.addOperation {
+            do {
+                try self.opFileManager.evictUbiquitousItem(at: self.url(of: path))
+                completionHandler?(nil)
+            } catch let e {
+                completionHandler?(e)
+            }
+        }
+    }
+    
+    /// Returns current version of file on this device and all versions of files in user devices.
+    /// - Parameter path: Path of file or directory.
+    /// - Parameter completionHandler: Retrieve current version on this device and all versions available. `currentVersion` will be nil if file doesn't exist. If an error parameter was provided, a presentable `Error` will be returned.
+    func versionsOfItem(path: String, completionHandler: @escaping ((_ currentVersion: NSFileVersion?, _ versions: [NSFileVersion], _ error: Error?) -> Void)) {
+        NotImplemented()
+    }
+    
+    /// Resolves conflicts by selecting a version.
+    /// - Parameter path: Path of file or directory.
+    /// - Parameter version: Version than will be choose as main version. `nil` value indicates current version on this device will be selected.
+    /// - Parameter completionHandler: If an error parameter was provided, a presentable `Error` will be returned.
+    func selectVersionOfItem(path: String, version: NSFileVersion? = nil, completionHandler: SimpleCompletionHandler) {
+        NotImplemented()
+    }
 }

 /// Scope of iCloud, wrapper for NSMetadataQueryUbiquitous...Scope constants
@@ -767,9 +727,13 @@ public enum UbiquitousScope: RawRepresentable {
    /// Search all files not in the Documents directories of the app’s iCloud container directories.
    /// Use this scope to store user-related data files that your app needs to share 
    /// but that are not files you want the user to manipulate directly.
+    ///
+    /// Raw value is equivalent to `NSMetadataQueryUbiquitousDataScope`
    case data
    /// Search all files in the Documents directories of the app’s iCloud container directories.
    /// Put documents that the user is allowed to access inside a Documents subdirectory.
+    ///
+    /// Raw value is equivalent to `NSMetadataQueryUbiquitousDocumentsScope`
    case documents
    
    public typealias RawValue = String
@@ -16,70 +16,14 @@ 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 let baseURL: URL?
-    open var currentPath: String
+open class DropboxFileProvider: HTTPFileProvider, FileProviderSharing {
+    override open class var type: String { return "Dropbox" }
    
    /// Dropbox RPC API URL, which is equal with [https://api.dropboxapi.com/2/](https://api.dropboxapi.com/2/)
    open let apiURL: URL
    /// Dropbox contents download/upload API URL, which is equal with [https://content.dropboxapi.com/2/](https://content.dropboxapi.com/2/)
    open let contentURL: URL
    
-    open var dispatch_queue: DispatchQueue
-    open var operation_queue: OperationQueue {
-        willSet {
-            assert(_session == nil, "It's not effective to change dispatch_queue property after session is initialized.")
-        }
-    }
-    
-    open weak var delegate: FileProviderDelegate?
-    open var credential: URLCredential? {
-        didSet {
-            sessionDelegate?.credential = self.credential
-        }
-    }
-    open private(set) var cache: URLCache?
-    public var useCache: Bool
-    public var validatingCache: Bool
-   
-    fileprivate var _session: URLSession?
-    internal fileprivate(set) var sessionDelegate: SessionDelegate?
-    public var session: URLSession {
-        get {
-            if _session == nil {
-                self.sessionDelegate = SessionDelegate(fileProvider: self)
-                let config = URLSessionConfiguration.default
-                config.urlCache = cache
-                config.requestCachePolicy = .returnCacheDataElseLoad
-                _session = URLSession(configuration: config, delegate: sessionDelegate as URLSessionDelegate?, delegateQueue: self.operation_queue)
-                _session!.sessionDescription = UUID().uuidString
-                initEmptySessionHandler(_session!.sessionDescription!)
-            }
-            return _session!
-        }
-        
-        set {
-            assert(newValue.delegate is SessionDelegate, "session instances should have a SessionDelegate instance as delegate.")
-            _session = newValue
-            if session.sessionDescription?.isEmpty ?? true {
-                _session?.sessionDescription = UUID().uuidString
-            }
-            self.sessionDelegate = newValue.delegate as? SessionDelegate
-            initEmptySessionHandler(_session!.sessionDescription!)
-        }
-    }
-    
-    fileprivate var _longpollSession: URLSession?
-    internal var longpollSession: URLSession {
-        if _longpollSession == nil {
-            let config = URLSessionConfiguration.default
-            config.timeoutIntervalForRequest = 600
-            _longpollSession = URLSession(configuration: config, delegate: nil, delegateQueue: nil)
-        }
-        return _longpollSession!
-    }
-    
    /**
     Initializer for Dropbox provider with given client ID and Token.
     These parameters must be retrieved via [OAuth2 API of Dropbox](https://www.dropbox.com/developers/reference/oauth-guide).
@@ -91,24 +35,9 @@ open class DropboxFileProvider: FileProviderBasicRemote {
     - Parameter cache: A URLCache to cache downloaded files and contents.
    */
    public init(credential: URLCredential?, cache: URLCache? = nil) {
-        self.baseURL = nil
-        self.currentPath = ""
-        self.useCache = false
-        self.validatingCache = true
-        self.cache = cache
-        self.credential = credential
-        
        self.apiURL = URL(string: "https://api.dropboxapi.com/2/")!
        self.contentURL = URL(string: "https://content.dropboxapi.com/2/")!
-        
-        #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"
+        super.init(baseURL: nil, credential: credential, cache: cache)
    }
    
    public required convenience init?(coder aDecoder: NSCoder) {
@@ -118,18 +47,7 @@ open class DropboxFileProvider: FileProviderBasicRemote {
        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 {
+    override open func copy(with zone: NSZone? = nil) -> Any {
        let copy = DropboxFileProvider(credential: self.credential, cache: self.cache)
        copy.currentPath = self.currentPath
        copy.delegate = self.delegate
@@ -139,32 +57,19 @@ open class DropboxFileProvider: FileProviderBasicRemote {
        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)) {
+    open override func contentsOfDirectory(path: String, completionHandler: @escaping ((_ contents: [FileObject], _ error: Error?) -> Void)) {
        let progress = Progress(parent: nil, userInfo: nil)
        list(path, progress: progress) { (contents, cursor, error) in
            completionHandler(contents, error)
        }
    }
    
-    open func attributesOfItem(path: String, completionHandler: @escaping ((_ attributes: FileObject?, _ error: Error?) -> Void)) {
+    open override func attributesOfItem(path: String, completionHandler: @escaping ((_ attributes: FileObject?, _ error: Error?) -> Void)) {
        let url = URL(string: "files/get_metadata", relativeTo: apiURL)!
        var request = URLRequest(url: url)
        request.httpMethod = "POST"
        request.set(httpAuthentication: credential, with: .oAuth2)
-        request.set(contentType: .json)
+        request.set(httpContentType: .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
@@ -182,7 +87,7 @@ open class DropboxFileProvider: FileProviderBasicRemote {
        task.resume()
    }
    
-    open func storageProperties(completionHandler: @escaping ((_ total: Int64, _ used: Int64) -> Void)) {
+    open override func storageProperties(completionHandler: @escaping ((_ total: Int64, _ used: Int64) -> Void)) {
        let url = URL(string: "users/get_space_usage", relativeTo: apiURL)!
        var request = URLRequest(url: url)
        request.httpMethod = "POST"
@@ -199,7 +104,7 @@ open class DropboxFileProvider: FileProviderBasicRemote {
        task.resume()
    }
    
-    open func searchFiles(path: String, recursive: Bool, query: NSPredicate, foundItemHandler: ((FileObject) -> Void)?, completionHandler: @escaping ((_ files: [FileObject], _ error: Error?) -> Void)) -> Progress? {
+    open override func searchFiles(path: String, recursive: Bool, query: NSPredicate, foundItemHandler: ((FileObject) -> Void)?, completionHandler: @escaping ((_ files: [FileObject], _ error: Error?) -> Void)) -> Progress? {
        let progress = Progress(parent: nil, userInfo: nil)
        var foundFiles = [DropboxFileObject]()
        if let queryStr = query.findValue(forKey: "name", operator: .beginsWith) as? String {
@@ -228,63 +133,72 @@ open class DropboxFileProvider: FileProviderBasicRemote {
        return progress
    }
    
-    open func isReachable(completionHandler: @escaping (Bool) -> Void) {
-        self.storageProperties { total, _ in
-            completionHandler(total > 0)
+    override func request(for operation: FileOperationType, overwrite: Bool = false, attributes: [URLResourceKey : Any] = [:]) -> URLRequest {
+        // content operations
+        var request: URLRequest
+        switch operation {
+        case .copy(source: let source, destination: let dest) where dest.lowercased().hasPrefix("file://"):
+            let url = URL(string: "files/download", relativeTo: contentURL)!
+            request = URLRequest(url: url)
+            request.set(httpAuthentication: credential, with: .oAuth2)
+            request.set(dropboxArgKey: ["path": correctPath(source)! as NSString])
+        case .fetch(let path):
+            let url = URL(string: "files/download", relativeTo: contentURL)!
+            request = URLRequest(url: url)
+            request.set(httpAuthentication: credential, with: .oAuth2)
+            request.set(dropboxArgKey: ["path": correctPath(path)! as NSString])
+        case .copy(source: let source, destination: let dest) where source.lowercased().hasPrefix("file://"):
+            var requestDictionary = [String: AnyObject]()
+            let url: URL = URL(string: "files/upload", relativeTo: contentURL)!
+            requestDictionary["path"] = correctPath(dest) as NSString?
+            requestDictionary["mode"] = (overwrite ? "overwrite" : "add") as NSString
+            requestDictionary["client_modified"] = (attributes[.contentModificationDateKey] as? Date)?.format(with: .rfc3339) as NSString?
+            request = URLRequest(url: url)
+            request.httpMethod = "POST"
+            request.set(httpAuthentication: credential, with: .oAuth2)
+            request.set(httpContentType: .stream)
+            request.set(dropboxArgKey: requestDictionary)
+        case .modify(let path):
+            var requestDictionary = [String: AnyObject]()
+            let url: URL = URL(string: "files/upload", relativeTo: contentURL)!
+            requestDictionary["path"] = correctPath(path) as NSString?
+            requestDictionary["mode"] = (overwrite ? "overwrite" : "add") as NSString
+            requestDictionary["client_modified"] = (attributes[.contentModificationDateKey] as? Date)?.format(with: .rfc3339) as NSString?
+            request = URLRequest(url: url)
+            request.httpMethod = "POST"
+            request.set(httpAuthentication: credential, with: .oAuth2)
+            request.set(httpContentType: .stream)
+            request.set(dropboxArgKey: requestDictionary)
+        default:
+            return self.apiRequest(for: operation, overwrite: overwrite)
        }
+        return request
    }
    
-    open weak var fileOperationDelegate: FileOperationDelegate?
-}
-
-extension DropboxFileProvider: FileProviderOperations {
-    open func create(folder folderName: String, at atPath: String, completionHandler: SimpleCompletionHandler) -> Progress? {
-        let path = (atPath as NSString).appendingPathComponent(folderName) + "/"
-        return doOperation(.create(path: path), completionHandler: completionHandler)
-    }
-    
-    open func moveItem(path: String, to toPath: String, overwrite: Bool, completionHandler: SimpleCompletionHandler) -> Progress? {
-        return doOperation(.move(source: path, destination: toPath), completionHandler: completionHandler)
-    }
-    
-    open func copyItem(path: String, to toPath: String, overwrite: Bool, completionHandler: SimpleCompletionHandler) -> Progress? {
-        return doOperation(.copy(source: path, destination: toPath), completionHandler: completionHandler)
-    }
-    
-    open func removeItem(path: String, completionHandler: SimpleCompletionHandler) -> Progress? {
-        return doOperation(.remove(path: path), completionHandler: completionHandler)
-    }
-    
-    fileprivate func doOperation(_ operation: FileOperationType, completionHandler: SimpleCompletionHandler) -> Progress? {
-        guard fileOperationDelegate?.fileProvider(self, shouldDoOperation: operation) ?? true == true else {
-            return nil
-        }
-        
-        let progress = Progress(totalUnitCount: 1)
-        progress.setUserInfoObject(operation, forKey: .fileProvderOperationTypeKey)
-        progress.kind = .file
-        progress.setUserInfoObject(Progress.FileOperationKind.downloading, forKey: .fileOperationKindKey)
-        
+    func apiRequest(for operation: FileOperationType, overwrite: Bool = false) -> URLRequest {
        let url: String
-        guard let sourcePath = operation.source else { return nil }
+        let sourcePath = operation.source
        let destPath = operation.destination
+        var requestDictionary = [String: AnyObject]()
        switch operation {
        case .create:
-            url = "files/create_folder"
+            url = "files/create_folder_v2"
+            
        case .copy:
-            url = "files/copy"
+            url = "files/copy_v2"
+            requestDictionary["allow_shared_folder"] = NSNumber(value: true)
        case .move:
-            url = "files/move"
+            url = "files/move_v2"
+            requestDictionary["allow_shared_folder"] = NSNumber(value: true)
        case .remove:
-            url = "files/delete"
+            url = "files/delete_v2"
        default: // modify, link, fetch
-            return nil
+            fatalError("Unimplemented operation \(operation.description) in \(#file)")
        }
        var request = URLRequest(url: URL(string: url, relativeTo: apiURL)!)
        request.httpMethod = "POST"
        request.set(httpAuthentication: credential, with: .oAuth2)
-        request.set(contentType: .json)
-        var requestDictionary = [String: AnyObject]()
+        request.set(httpContentType: .json)
        if let dest = correctPath(destPath) as NSString? {
            requestDictionary["from_path"] = correctPath(sourcePath) as NSString?
            requestDictionary["to_path"] = dest
@@ -292,162 +206,25 @@ extension DropboxFileProvider: FileProviderOperations {
            requestDictionary["path"] = correctPath(sourcePath) as NSString?
        }
        request.httpBody = Data(jsonDictionary: requestDictionary)
-        let task = session.dataTask(with: request, completionHandler: { (data, response, error) in
-            var serverError: FileProviderDropboxError?
-            if let response = response as? HTTPURLResponse, response.statusCode >= 300, let code = FileProviderHTTPErrorCode(rawValue: response.statusCode) {
-                 serverError = FileProviderDropboxError(code: code, path: sourcePath, errorDescription: String(data: data ?? Data(), encoding: .utf8))
-            }
-            if serverError == nil && error == nil {
-                progress.completedUnitCount = 1
-            } else {
-                progress.cancel()
-            }
-            completionHandler?(serverError ?? error)
-            self.delegateNotify(operation, error: serverError ?? error)
-        })
-        task.taskDescription = operation.json
-        progress.cancellationHandler = { [weak task] in
-            task?.cancel()
-        }
-        progress.setUserInfoObject(Date(), forKey: .startingTimeKey)
-        task.resume()
-        return progress
+        return request
    }
    
-    open func copyItem(localFile: URL, to toPath: String, overwrite: Bool, completionHandler: SimpleCompletionHandler) -> Progress? {
-        // check file is not a folder
-        guard (try? localFile.resourceValues(forKeys: [.fileResourceTypeKey]))?.fileResourceType ?? .unknown == .regular else {
-            dispatch_queue.async {
-                completionHandler?(self.throwError(localFile.path, code: URLError.fileIsDirectory))
-            }
-            return nil
-        }
-        
-        let opType = FileOperationType.copy(source: localFile.absoluteString, destination: toPath)
-        guard fileOperationDelegate?.fileProvider(self, shouldDoOperation: opType) ?? true == true else {
-            return nil
-        }
-        return upload_simple(toPath, localFile: localFile, overwrite: overwrite, operation: opType, completionHandler: completionHandler)
+    override func serverError(with code: FileProviderHTTPErrorCode, path: String?, data: Data?) -> FileProviderHTTPError {
+        return FileProviderDropboxError(code: code, path: path ?? "", errorDescription: data.flatMap({ String(data: $0, encoding: .utf8) }))
    }
    
-    open func copyItem(path: String, toLocalURL destURL: URL, completionHandler: SimpleCompletionHandler) -> Progress? {
-        let opType = FileOperationType.copy(source: path, destination: destURL.absoluteString)
-        guard fileOperationDelegate?.fileProvider(self, shouldDoOperation: opType) ?? true == true else {
-            return nil
-        }
-        let url = URL(string: "files/download", relativeTo: contentURL)!
-        
-        var progress = Progress(parent: nil, userInfo: nil)
-        progress.setUserInfoObject(opType, forKey: .fileProvderOperationTypeKey)
-        progress.kind = .file
-        progress.setUserInfoObject(Progress.FileOperationKind.downloading, forKey: .fileOperationKindKey)
-        
-        var request = URLRequest(url: url)
-        request.set(httpAuthentication: credential, with: .oAuth2)
-        request.set(dropboxArgKey: ["path": path as NSString])
-        let task = session.downloadTask(with: request)
-        completionHandlersForTasks[session.sessionDescription!]?[task.taskIdentifier] = { error in
-            if error != nil {
-                progress.cancel()
-            }
+    override func upload_simple(_ targetPath: String, request: URLRequest, data: Data?, localFile: URL?, operation: FileOperationType, completionHandler: SimpleCompletionHandler) -> Progress? {
+        let size = data?.count ?? Int((try? localFile?.resourceValues(forKeys: [.fileSizeKey]))??.fileSize ?? -1)
+        if size > 150 * 1024 * 1024 {
+            let error = FileProviderDropboxError(code: .payloadTooLarge, path: targetPath, errorDescription: nil)
            completionHandler?(error)
+            self.delegateNotify(operation, error: error)
+            return nil
        }
-        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
-                if serverError != nil {
-                    progress.cancel()
-                }
-                completionHandler?(serverError)
-                return
-            }
-            do {
-                try FileManager.default.moveItem(at: tempURL, to: destURL)
-                completionHandler?(nil)
-            } catch let e {
-                completionHandler?(e)
-            }
-        }
-        task.taskDescription = opType.json
-        task.addObserver(sessionDelegate!, forKeyPath: #keyPath(URLSessionTask.countOfBytesReceived), options: .new, context: &progress)
-        task.addObserver(sessionDelegate!, forKeyPath: #keyPath(URLSessionTask.countOfBytesExpectedToReceive), options: .new, context: &progress)
-        progress.cancellationHandler = { [weak task] in
-            task?.cancel()
-        }
-        progress.setUserInfoObject(Date(), forKey: .startingTimeKey)
-        task.resume()
-        return progress
+        
+        return super.upload_simple(targetPath, request: request, data: data, localFile: localFile, operation: operation, completionHandler: completionHandler)
    }
-}

-extension DropboxFileProvider: FileProviderReadWrite {
-    open func contents(path: String, offset: Int64, length: Int, completionHandler: @escaping ((_ contents: Data?, _ error: Error?) -> Void)) -> Progress? {
-        if length == 0 || offset < 0 {
-            dispatch_queue.async {
-                completionHandler(Data(), nil)
-            }
-            return nil
-        }
-        
-        let opType = FileOperationType.fetch(path: path)
-        let url = URL(string: "files/download", relativeTo: contentURL)!
-        
-        var progress = Progress(parent: nil, userInfo: nil)
-        progress.setUserInfoObject(opType, forKey: .fileProvderOperationTypeKey)
-        progress.kind = .file
-        progress.setUserInfoObject(Progress.FileOperationKind.downloading, forKey: .fileOperationKindKey)
-        
-        var request = URLRequest(url: url)
-        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
-            if error != nil {
-                progress.cancel()
-            }
-            completionHandler(nil, error)
-        }
-        downloadCompletionHandlersForTasks[session.sessionDescription!]?[task.taskIdentifier] = { tempURL in            
-            guard let httpResponse = task.response as? HTTPURLResponse , httpResponse.statusCode < 300 else {
-                let code = FileProviderHTTPErrorCode(rawValue: (task.response as? HTTPURLResponse)?.statusCode ?? -1)
-                let errorData : Data? = nil //Data(contentsOf:cacheURL) // TODO: Figure out how to get error response data for the error description
-                let serverError : FileProviderDropboxError? = code != nil ? FileProviderDropboxError(code: code!, path: path, errorDescription: String(data: errorData ?? Data(), encoding: .utf8)) : nil
-                if serverError != nil {
-                    progress.cancel()
-                }
-                completionHandler(nil, serverError)
-                return
-            }
-            do {
-                let data = try Data(contentsOf: tempURL)
-                completionHandler(data, nil)
-            } catch let e {
-                completionHandler(nil, e)
-            }
-        }
-        task.taskDescription = opType.json
-        task.addObserver(sessionDelegate!, forKeyPath: #keyPath(URLSessionTask.countOfBytesReceived), options: .new, context: &progress)
-        task.addObserver(sessionDelegate!, forKeyPath: #keyPath(URLSessionTask.countOfBytesExpectedToReceive), options: .new, context: &progress)
-        progress.cancellationHandler = { [weak task] in
-            task?.cancel()
-        }
-        progress.setUserInfoObject(Date(), forKey: .startingTimeKey)
-        task.resume()
-        return progress
-    }
-    
-    public func writeContents(path: String, contents data: Data?, atomically: Bool, overwrite: Bool, completionHandler: SimpleCompletionHandler) -> Progress? {
-        let opType = FileOperationType.modify(path: path)
-        guard fileOperationDelegate?.fileProvider(self, shouldDoOperation: opType) ?? true == true else {
-            return nil
-        }
-        // FIXME: remove 150MB restriction
-        return upload_simple(path, data: data ?? Data(), overwrite: overwrite, operation: opType, completionHandler: completionHandler)
-    }
-    
    /*
    fileprivate func registerNotifcation(path: String, eventHandler: (() -> Void)) {
        /* There is two ways to monitor folders changing in Dropbox. Either using webooks
@@ -463,15 +240,13 @@ extension DropboxFileProvider: FileProviderReadWrite {
    }
    */
    // TODO: Implement /get_account & /get_current_account
-}
-
-extension DropboxFileProvider: FileProviderSharing {
+    
    open func publicLink(to path: String, completionHandler: @escaping ((_ link: URL?, _ attribute: FileObject?, _ expiration: Date?, _ error: Error?) -> Void)) {
        let url = URL(string: "files/get_temporary_link", relativeTo: apiURL)!
        var request = URLRequest(url: url)
        request.httpMethod = "POST"
        request.set(httpAuthentication: credential, with: .oAuth2)
-        request.set(contentType: .json)
+        request.set(httpContentType: .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
@@ -517,7 +292,7 @@ extension DropboxFileProvider: FileProviderSharing {
        var request = URLRequest(url: url)
        request.httpMethod = "POST"
        request.set(httpAuthentication: credential, with: .oAuth2)
-        request.set(contentType: .json)
+        request.set(httpContentType: .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
@@ -552,7 +327,7 @@ extension DropboxFileProvider: FileProviderSharing {
        var request = URLRequest(url: url)
        request.httpMethod = "POST"
        request.set(httpAuthentication: credential, with: .oAuth2)
-        request.set(contentType: .json)
+        request.set(httpContentType: .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
@@ -635,7 +410,7 @@ extension DropboxFileProvider: ExtendedFileProvider {
            var image: ImageClass? = nil
            if let r = response as? HTTPURLResponse, let result = r.allHeaderFields["Dropbox-API-Result"] as? String, let jsonResult = result.deserializeJSON() {
                if jsonResult["error"] != nil {
-                    completionHandler(nil, self.throwError(path, code: URLError.cannotDecodeRawData as FoundationErrorEnum))
+                    completionHandler(nil, self.throwError(path, code: URLError.cannotDecodeRawData))
                }
            }
            if let data = data {
@@ -661,7 +436,7 @@ extension DropboxFileProvider: ExtendedFileProvider {
        var request = URLRequest(url: url)
        request.httpMethod = "POST"
        request.set(httpAuthentication: credential, with: .oAuth2)
-        request.set(contentType: .json)
+        request.set(httpContentType: .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
@@ -680,5 +455,3 @@ extension DropboxFileProvider: ExtendedFileProvider {
        task.resume()
    }
 }
-
-extension DropboxFileProvider: FileProvider { }
@@ -23,6 +23,10 @@ public final class DropboxFileObject: FileObject {
    }
    
    internal init? (json: [String: AnyObject]) {
+        var json = json
+        if json["name"] == nil, let metadata = json["metadata"] as? [String: AnyObject] {
+            json = metadata
+        }
        guard let name = json["name"] as? String else { return nil }
        guard let path = json["path_display"] as? String else { return nil }
        super.init(url: nil, name: name, path: path)
@@ -89,7 +93,7 @@ internal extension DropboxFileProvider {
        var request = URLRequest(url: url)
        request.httpMethod = "POST"
        request.set(httpAuthentication: credential, with: .oAuth2)
-        request.set(contentType: .json)
+        request.set(httpContentType: .json)
        request.httpBody = Data(jsonDictionary: requestDictionary)
        let task = (session ?? self.session).dataTask(with: request, completionHandler: { (data, response, error) in
            var responseError: FileProviderDropboxError?
@@ -126,63 +130,6 @@ internal extension DropboxFileProvider {
        task.resume()
    }
    
-    func upload_simple(_ targetPath: String, data: Data? = nil, localFile: URL? = nil, modifiedDate: Date = Date(), overwrite: Bool, operation: FileOperationType, completionHandler: SimpleCompletionHandler) -> Progress? {
-        let size = data?.count ?? Int((try? localFile?.resourceValues(forKeys: [.fileSizeKey]))??.fileSize ?? -1)
-        if size > 150 * 1024 * 1024 {
-            let error = FileProviderDropboxError(code: .payloadTooLarge, path: targetPath, errorDescription: nil)
-            completionHandler?(error)
-            self.delegateNotify(.create(path: targetPath), error: error)
-            return nil
-        }
-        
-        var progress = Progress(parent: nil, userInfo: nil)
-        progress.setUserInfoObject(operation, forKey: .fileProvderOperationTypeKey)
-        progress.kind = .file
-        progress.setUserInfoObject(Progress.FileOperationKind.downloading, forKey: .fileOperationKindKey)
-        progress.totalUnitCount = Int64(size)
-        
-        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"] = modifiedDate.rfc3339utc() as NSString
-        var request = URLRequest(url: url)
-        request.httpMethod = "POST"
-        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 = (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)
-            }
-            if !(responseError == nil && error == nil) {
-                progress.cancel()
-            }
-            completionHandler?(responseError ?? error)
-            self?.delegateNotify(.modify(path: targetPath), error: responseError ?? error)
-        }
-        task.taskDescription = operation.json
-        task.addObserver(sessionDelegate!, forKeyPath: #keyPath(URLSessionTask.countOfBytesSent), options: .new, context: &progress)
-        progress.cancellationHandler = { [weak task] in
-            task?.cancel()
-        }
-        progress.setUserInfoObject(Date(), forKey: .startingTimeKey)
-        task.resume()
-        return progress
-    }
-    
    func search(_ startPath: String = "", query: String, start: Int = 0, maxResultPerPage: Int = 25, maxResults: Int = -1, progress: Progress, foundItem:@escaping ((_ file: DropboxFileObject) -> Void), completionHandler: @escaping ((_ error: Error?) -> Void)) {
        if progress.isCancelled { return }
        
@@ -190,7 +137,7 @@ internal extension DropboxFileProvider {
        var request = URLRequest(url: url)
        request.httpMethod = "POST"
        request.set(httpAuthentication: credential, with: .oAuth2)
-        request.set(contentType: .json)
+        request.set(httpContentType: .json)
        var requestDictionary: [String: AnyObject] = ["path": startPath as NSString]
        requestDictionary["query"] = query as NSString
        requestDictionary["start"] = start as NSNumber
@@ -261,14 +208,4 @@ internal extension DropboxFileProvider {
        }
        return (dic, keys)
    }
-    
-    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)
-            }
-        })
-    }
 }
@@ -21,6 +21,12 @@ public extension Array where Element: FileObject {
    }
 }

+public extension Sequence where Iterator.Element == UInt8 {
+    func hexString() -> String {
+        return self.map{String(format: "%02X", $0)}.joined()
+    }
+}
+
 public extension URLFileResourceType {
    /// **FileProvider** returns corresponding `URLFileResourceType` of a `FileAttributeType` value
    public init(fileTypeValue: FileAttributeType) {
@@ -51,8 +57,10 @@ public extension URLResourceKey {
 }

 public extension ProgressUserInfoKey {
+    /// **FileProvider** returns associated `FileProviderOperationType`
    public static let fileProvderOperationTypeKey = ProgressUserInfoKey("FilesProviderOperationTypeKey")
-    public static let startingTimeKey = ProgressUserInfoKey("NSProgressstartingTimeKey")
+    /// **FileProvider** returns start date/time of operation
+    public static let startingTimeKey = ProgressUserInfoKey("NSProgressStartingTimeKey")
 }

 internal extension URL {
@@ -73,8 +81,41 @@ internal extension URL {
    }
 }

+public extension URLRequest {
+    /// Defines HTTP Authentication method required to access
+    public enum AuthenticationType {
+        /// 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
+    }
+}
+
+struct Quality<T> {
+    let value: T
+    let quality: Float
+    
+    var stringifed: String {
+        var representaion = String(describing: value)
+        let quality = min(1, max(self.quality, 0))
+        if let value = value as? Locale {
+            representaion = "\(value.identifier.replacingOccurrences(of: "_", with: "-"))"
+        }
+        if let value = value as? String.Encoding {
+            let cfEncoding = CFStringConvertNSStringEncodingToEncoding(value.rawValue)
+            representaion = CFStringConvertEncodingToIANACharSetName(cfEncoding) as String? ?? "*"
+        }
+        let qualityDesc = String(format: "%.1f", quality)
+        return "\(representaion); q=\(qualityDesc)"
+    }
+}
+
 internal extension URLRequest {
-    mutating func set(httpAuthentication credential: URLCredential?, with type: HTTPAuthenticationType) {
+    mutating func set(httpAuthentication credential: URLCredential?, with type: AuthenticationType) {
        func base64(_ str: String) -> String {
            let plainData = str.data(using: .utf8)
            let base64String = plainData!.base64EncodedString(options: [])
@@ -84,8 +125,12 @@ internal extension URLRequest {
        guard let credential = credential else { return }
        switch type {
        case .basic:
-            let authStr = "\(credential.user ?? ""):\(credential.password ?? "")"
-            self.setValue("Basic \(authStr)", forHTTPHeaderField: "Authorization")
+            let user = credential.user?.replacingOccurrences(of: ":", with: "") ?? ""
+            let pass = credential.password ?? ""
+            let authStr = "\(user):\(pass)"
+            if let base64Auth = authStr.data(using: .utf8)?.base64EncodedString() {
+                self.setValue("Basic \(base64Auth)", forHTTPHeaderField: "Authorization")
+            }
        case .digest:
            // handled by RemoteSessionDelegate
            break
@@ -100,7 +145,88 @@ internal extension URLRequest {
        }
    }
    
-    mutating func set(rangeWithOffset offset: Int64, length: Int) {
+    mutating func set(httpAcceptCharset acceptCharset: String.Encoding) {
+        let cfEncoding = CFStringConvertNSStringEncodingToEncoding(acceptCharset.rawValue)
+        if let charsetString = CFStringConvertEncodingToIANACharSetName(cfEncoding) as String? {
+            self.addValue(charsetString, forHTTPHeaderField: "Accept-Charset")
+        }
+    }
+    
+    mutating func set(httpAcceptCharset acceptCharset: Quality<String.Encoding>) {
+        self.addValue(acceptCharset.stringifed, forHTTPHeaderField: "Accept-Charset")
+    }
+    
+    mutating func set(httpAcceptCharsets acceptCharsets: [String.Encoding]) {
+        self.setValue(nil, forHTTPHeaderField: "Accept-Charset")
+        for charset in acceptCharsets {
+            let cfEncoding = CFStringConvertNSStringEncodingToEncoding(charset.rawValue)
+            if let charsetString = CFStringConvertEncodingToIANACharSetName(cfEncoding) as String? {
+                self.addValue(charsetString, forHTTPHeaderField: "Accept-Charset")
+            }
+        }
+    }
+    
+    mutating func set(httpAcceptCharsets acceptCharsets: [Quality<String.Encoding>]) {
+        self.setValue(nil, forHTTPHeaderField: "Accept-Charset")
+        for charset in acceptCharsets.sorted(by: { $0.quality > $1.quality }) {
+            self.addValue(charset.stringifed, forHTTPHeaderField: "Accept-Charset")
+        }
+    }
+    
+    enum Encoding: String {
+        case all = "*"
+        case identity
+        case gzip
+        case deflate
+    }
+    
+    mutating func set(httpAcceptEncoding acceptEncoding: Encoding) {
+        self.addValue(acceptEncoding.rawValue, forHTTPHeaderField: "Accept-Encoding")
+    }
+    
+    mutating func set(httpAcceptEncoding acceptEncoding: Quality<Encoding>) {
+        self.addValue(acceptEncoding.stringifed, forHTTPHeaderField: "Accept-Encoding")
+    }
+    
+    mutating func set(httpAcceptEncodings acceptEncodings: [Encoding]) {
+        self.setValue(nil, forHTTPHeaderField: "Accept-Encoding")
+        for encoding in acceptEncodings {
+            self.addValue(encoding.rawValue, forHTTPHeaderField: "Accept-Encoding")
+        }
+    }
+    
+    mutating func set(httpAcceptEncodings acceptEncodings: [Quality<Encoding>]) {
+        self.setValue(nil, forHTTPHeaderField: "Accept-Encoding")
+        for encoding in acceptEncodings.sorted(by: { $0.quality > $1.quality }) {
+            self.addValue(encoding.stringifed, forHTTPHeaderField: "Accept-Encoding")
+        }
+    }
+    
+    mutating func set(httpAcceptLanguage acceptLanguage: Locale) {
+        let langCode = acceptLanguage.identifier.replacingOccurrences(of: "_", with: "-")
+        self.addValue(langCode, forHTTPHeaderField: "Accept-Language")
+    }
+    
+    mutating func set(httpAcceptLanguage acceptLanguage: Quality<Locale>) {
+        self.addValue(acceptLanguage.stringifed, forHTTPHeaderField: "Accept-Language")
+    }
+    
+    mutating func set(httpAcceptLanguages acceptLanguages: [Locale]) {
+        self.setValue(nil, forHTTPHeaderField: "Accept-Language")
+        for lang in acceptLanguages {
+            let langCode = lang.identifier.replacingOccurrences(of: "_", with: "-")
+            self.addValue(langCode, forHTTPHeaderField: "Accept-Language")
+        }
+    }
+    
+    mutating func set(httpAcceptLanguages acceptLanguages: [Quality<Locale>]) {
+        self.setValue(nil, forHTTPHeaderField: "Accept-Language")
+        for lang in acceptLanguages.sorted(by: { $0.quality > $1.quality} ) {
+            self.addValue(lang.stringifed, forHTTPHeaderField: "Accept-Language")
+        }
+    }
+    
+    mutating func set(httpRangeWithOffset offset: Int64, length: Int) {
        if length > 0 {
            self.setValue("bytes=\(offset)-\(offset + Int64(length) - 1)", forHTTPHeaderField: "Range")
        } else if offset > 0 && length < 0 {
@@ -108,27 +234,51 @@ internal extension URLRequest {
        }
    }
    
-    enum ContentType: String {
-        case json = "application/json"
-        case stream = "application/octet-stream"
-        case xml = "text/xml; charset=\"utf-8\""
+    mutating func set(httpRange range: Range<Int>) {
+        let range = max(0, range.lowerBound)..<range.upperBound
+        if range.upperBound < Int.max && range.count > 0 {
+            self.setValue("bytes=\(range.lowerBound)-\(range.upperBound - 1)", forHTTPHeaderField: "Range")
+        } else if range.lowerBound > 0 {
+            self.setValue("bytes=\(range.lowerBound)-", forHTTPHeaderField: "Range")
+        }
    }
    
-    mutating func set(contentType: ContentType) {
-        self.setValue(contentType.rawValue, forHTTPHeaderField: "Content-Type")
+    struct ContentMIMEType: RawRepresentable {
+        public var rawValue: String
+        public typealias RawValue = String
+        
+        public init(rawValue: String) {
+            self.rawValue = rawValue
+        }
+        
+        static let javascript = ContentMIMEType(rawValue: "application/javascript")
+        static let json = ContentMIMEType(rawValue: "application/json")
+        static let pdf = ContentMIMEType(rawValue: "application/pdf")
+        static let stream = ContentMIMEType(rawValue: "application/octet-stream")
+        static let zip = ContentMIMEType(rawValue: "application/zip")
+        
+        // Texts
+        static let css = ContentMIMEType(rawValue: "text/css")
+        static let html = ContentMIMEType(rawValue: "text/html")
+        static let plainText = ContentMIMEType(rawValue: "text/plain")
+        static let xml = ContentMIMEType(rawValue: "text/xml")
+        
+        // Images
+        static let gif = ContentMIMEType(rawValue: "image/gif")
+        static let jpeg = ContentMIMEType(rawValue: "image/jpeg")
+        static let png = ContentMIMEType(rawValue: "image/png")
    }
    
-    private func asciiEscape(string:String) -> String {
-        var res = ""
-        for char in string.unicodeScalars {
-            let substring = String(char)
-            if substring.canBeConverted(to: .ascii) {
-                res.append(substring)
-            } else {
-                res = res.appendingFormat("\\u%04x", char.value)
+    mutating func set(httpContentType contentType: ContentMIMEType, charset: String.Encoding? = nil) {
+        var parameter = ""
+        if let charset = charset {
+            let cfEncoding = CFStringConvertNSStringEncodingToEncoding(charset.rawValue)
+            if let charsetString = CFStringConvertEncodingToIANACharSetName(cfEncoding) as String? {
+                parameter = ";charset=" + charsetString
            }
        }
-        return res
+        
+        self.setValue(contentType.rawValue + parameter, forHTTPHeaderField: "Content-Type")
    }
    
    mutating func set(dropboxArgKey requestDictionary: [String: AnyObject]) {
@@ -136,13 +286,16 @@ internal extension URLRequest {
            return
        }
        guard var jsonString = String(data: jsonData, encoding: .utf8) else { return }
-        jsonString = self.asciiEscape(string: jsonString)
-        jsonString = jsonString.replacingOccurrences(of: "\\/", with: "/")
+        jsonString = jsonString.asciiEscaped().replacingOccurrences(of: "\\/", with: "/")
        
        self.setValue(jsonString, forHTTPHeaderField: "Dropbox-API-Arg")
    }
 }

+internal extension CharacterSet {
+    static let filePathAllowed = CharacterSet.urlPathAllowed.subtracting(CharacterSet(charactersIn: ":"))
+}
+
 internal extension Data {
    internal var isPDF: Bool {
        return self.count > 4 && self.scanString(length: 4, using: .ascii) == "%PDF"
@@ -204,6 +357,19 @@ internal extension String {
        }
        return data.deserializeJSON()
    }
+    
+    func asciiEscaped() -> String {
+        var res = ""
+        for char in self.unicodeScalars {
+            let substring = String(char)
+            if substring.canBeConverted(to: .ascii) {
+                res.append(substring)
+            } else {
+                res = res.appendingFormat("\\u%04x", char.value)
+            }
+        }
+        return res
+    }
 }

 internal extension TimeInterval {
@@ -232,39 +398,51 @@ internal extension TimeInterval {
    }
 }

-internal extension Date {
-   init?(rfcString: String) {
+public extension Date {
+    /// Date formats used commonly in internet messaging defined by various RFCs.
+    public enum RFCStandards: String {
+        /// Date format defined by usenet, commonly used in old implementations.
+        case rfc850 = "EEEE',' dd'-'MMM'-'yy HH':'mm':'ss z"
+        /// Date format defined by RFC 1132 for http.
+        case rfc1123 = "EEE',' dd' 'MMM' 'yyyy HH':'mm':'ss z"
+        /// Date format defined by ISO 8601, also defined in RFC 3339. Used by Dropbox.
+        case iso8601 = "yyyy'-'MM'-'dd'T'HH':'mm':'ssZ"
+        /// Date string returned by asctime() function.
+        case asctime = "EEE MMM d HH':'mm':'ss yyyy"
+        
+        /// Equivalent to and defined by RFC 1123.
+        public static let http = RFCStandards.rfc1123
+        /// Equivalent to and defined by ISO 8610.
+        public static let rfc3339 = RFCStandards.iso8601
+        /// Equivalent to and defined by RFC 850.
+        public static let usenet = RFCStandards.rfc850
+        
+        // Sorted by commonness
+        fileprivate static let allValues: [RFCStandards] = [.rfc1123, .rfc850, .iso8601, .asctime]
+    }
+    
+    /// Checks date string against various RFC standards and returns `Date`.
+    public 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
+        
+        for standard in RFCStandards.allValues {
+            dateFor.dateFormat = standard.rawValue
+            if let date = dateFor.date(from: rfcString) {
+                self = date
+                return
+            }
        }
        
        return nil
    }
    
-    internal func rfc3339utc() -> String {
+    /// Formats date according to RFCs standard.
+    public func format(with standard: RFCStandards, locale: Locale? = nil, timeZone: TimeZone? = nil) -> 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")
+        fm.dateFormat = standard.rawValue
+        fm.timeZone = timeZone ?? TimeZone(identifier: "UTC")
+        fm.locale = locale ?? Locale(identifier: "en_US_POSIX")
        return fm.string(from: self)
    }
 }
@@ -0,0 +1,462 @@
+// Originally based on CryptoSwift by Marcin Krzyżanowski <marcin.krzyzanowski@gmail.com>
+// Copyright (C) 2014 Marcin Krzyżanowski <marcin.krzyzanowski@gmail.com>
+// This software is provided 'as-is', without any express or implied warranty.
+//
+// In no event will the authors be held liable for any damages arising from the use of this software.
+//
+// Permission is granted to anyone to use this software for any purpose,including commercial applications, and to alter it and redistribute it freely, subject to the following restrictions:
+//
+// - The origin of this software must not be misrepresented; you must not claim that you wrote the original software. If you use this software in a product, an acknowledgment in the product documentation is required.
+// - Altered source versions must be plainly marked as such, and must not be misrepresented as being the original software.
+// - This notice may not be removed or altered from any source or binary distribution.
+
+import Foundation
+
+protocol SHA2Variant {
+    static var size: Int { get }
+    static var h: [UInt64] { get }
+    static var k: [UInt64] { get }
+    
+    static func resultingArray<T>(_ hh:[T]) -> ArraySlice<T>
+    static func calculate(_ message: [UInt8]) -> [UInt8]
+}
+
+protocol SHA2Variant32: SHA2Variant { }
+protocol SHA2Variant64: SHA2Variant { }
+
+extension SHA2Variant32 {
+    static func calculate(_ message: [UInt8]) -> [UInt8] {
+        var tmpMessage = message
+        
+        let len = 64
+        
+        // Step 1. Append Padding Bits
+        tmpMessage.append(0x80) // append one bit (UInt8 with one bit) to message
+        
+        // append "0" bit until message length in bits ≡ 448 (mod 512)
+        var msgLength = tmpMessage.count
+        var counter = 0
+        
+        while msgLength % len != (len - 8) {
+            counter += 1
+            msgLength += 1
+        }
+        
+        tmpMessage += [UInt8](repeating: 0, count: counter)
+        
+        // hash values
+        var hh = [UInt32]()
+        Self.h.forEach {(h) -> () in
+            hh.append(UInt32(h))
+        }
+        
+        // append message length, in a 64-bit big-endian integer. So now the message length is a multiple of 512 bits.
+        tmpMessage += arrayOfBytes(message.count * 8, length: 64 / 8)
+        
+        // Process the message in successive 512-bit chunks:
+        let chunkSizeBytes = 512 / 8 // 64
+        for chunk in BytesSequence(chunkSize: chunkSizeBytes, data: tmpMessage) {
+            // break chunk into sixteen 32-bit words M[j], 0 ≤ j ≤ 15, big-endian
+            // Extend the sixteen 32-bit words into sixty-four 32-bit words:
+            var M:[UInt32] = [UInt32](repeating: 0, count: Self.k.count)
+            for x in 0..<M.count {
+                switch (x) {
+                case 0...15:
+                    let start = chunk.startIndex + (x * MemoryLayout.size(ofValue: M[x]))
+                    let end = start + MemoryLayout.size(ofValue: M[x])
+                    let le = toUInt32Array(chunk[start..<end])[0]
+                    M[x] = le.bigEndian
+                    break
+                default:
+                    let s0 = rotateRight(M[x-15], n: 7) ^ rotateRight(M[x-15], n: 18) ^ (M[x-15] >> 3) //FIXME: n
+                    let s1 = rotateRight(M[x-2], n: 17) ^ rotateRight(M[x-2], n: 19) ^ (M[x-2] >> 10)
+                    M[x] = M[x-16] &+ s0 &+ M[x-7] &+ s1
+                    break
+                }
+            }
+            
+            var A = hh[0]
+            var B = hh[1]
+            var C = hh[2]
+            var D = hh[3]
+            var E = hh[4]
+            var F = hh[5]
+            var G = hh[6]
+            var H = hh[7]
+            
+            // Main loop
+            for j in 0..<Self.k.count {
+                let s0 = rotateRight(A,n: 2) ^ rotateRight(A,n: 13) ^ rotateRight(A,n: 22)
+                let maj = (A & B) ^ (A & C) ^ (B & C)
+                let t2 = s0 &+ maj
+                let s1 = rotateRight(E,n: 6) ^ rotateRight(E,n: 11) ^ rotateRight(E,n: 25)
+                let ch = (E & F) ^ ((~E) & G)
+                let t1 = H &+ s1 &+ ch &+ UInt32(Self.k[j]) &+ M[j]
+                
+                H = G
+                G = F
+                F = E
+                E = D &+ t1
+                D = C
+                C = B
+                B = A
+                A = t1 &+ t2
+            }
+            
+            hh[0] = (hh[0] &+ A)
+            hh[1] = (hh[1] &+ B)
+            hh[2] = (hh[2] &+ C)
+            hh[3] = (hh[3] &+ D)
+            hh[4] = (hh[4] &+ E)
+            hh[5] = (hh[5] &+ F)
+            hh[6] = (hh[6] &+ G)
+            hh[7] = (hh[7] &+ H)
+        }
+        
+        // Produce the final hash value (big-endian) as a 160 bit number:
+        var result = [UInt8]()
+        result.reserveCapacity(hh.count / 4)
+        Self.resultingArray(hh).forEach {
+            let item = $0.bigEndian
+            result += [UInt8(item & 0xff), UInt8((item >> 8) & 0xff), UInt8((item >> 16) & 0xff), UInt8((item >> 24) & 0xff)]
+        }
+        return result
+    }
+}
+
+extension SHA2Variant64 {
+    static func calculate(_ message: [UInt8]) -> [UInt8] {
+        var tmpMessage = message
+        
+        let len = 128
+        
+        // Step 1. Append Padding Bits
+        tmpMessage.append(0x80) // append one bit (UInt8 with one bit) to message
+        
+        // append "0" bit until message length in bits ≡ 448 (mod 512)
+        var msgLength = tmpMessage.count
+        var counter = 0
+        
+        while msgLength % len != (len - 8) {
+            counter += 1
+            msgLength += 1
+        }
+        
+        tmpMessage += [UInt8](repeating: 0, count: counter)
+        
+        // hash values
+        var hh = [UInt64]()
+        Self.h.forEach {(h) -> () in
+            hh.append(h)
+        }
+        
+        
+        // append message length, in a 64-bit big-endian integer. So now the message length is a multiple of 512 bits.
+        tmpMessage += arrayOfBytes(message.count * 8, length: 64 / 8)
+        
+        // Process the message in successive 1024-bit chunks:
+        let chunkSizeBytes = 1024 / 8 // 128
+        for chunk in BytesSequence(chunkSize: chunkSizeBytes, data: tmpMessage) {
+            // break chunk into sixteen 64-bit words M[j], 0 ≤ j ≤ 15, big-endian
+            // Extend the sixteen 64-bit words into eighty 64-bit words:
+            var M = [UInt64](repeating: 0, count: Self.k.count)
+            for x in 0..<M.count {
+                switch (x) {
+                case 0...15:
+                    let start = chunk.startIndex + (x * MemoryLayout.size(ofValue: M[x]))
+                    let end = start + MemoryLayout.size(ofValue: M[x])
+                    let le = toUInt64Array(chunk[start..<end])[0]
+                    M[x] = le.bigEndian
+                    break
+                default:
+                    let s0 = rotateRight(M[x-15], n: 1) ^ rotateRight(M[x-15], n: 8) ^ (M[x-15] >> 7)
+                    let s1 = rotateRight(M[x-2], n: 19) ^ rotateRight(M[x-2], n: 61) ^ (M[x-2] >> 6)
+                    M[x] = M[x-16] &+ s0 &+ M[x-7] &+ s1
+                    break
+                }
+            }
+            
+            var A = hh[0]
+            var B = hh[1]
+            var C = hh[2]
+            var D = hh[3]
+            var E = hh[4]
+            var F = hh[5]
+            var G = hh[6]
+            var H = hh[7]
+            
+            // Main loop
+            for j in 0..<Self.k.count {
+                let s0 = rotateRight(A,n: 28) ^ rotateRight(A,n: 34) ^ rotateRight(A,n: 39) //FIXME: n:
+                let maj = (A & B) ^ (A & C) ^ (B & C)
+                let t2 = s0 &+ maj
+                let s1 = rotateRight(E,n: 14) ^ rotateRight(E,n: 18) ^ rotateRight(E,n: 41)
+                let ch = (E & F) ^ ((~E) & G)
+                let t1 = H &+ s1 &+ ch &+ Self.k[j] &+ UInt64(M[j])
+                
+                H = G
+                G = F
+                F = E
+                E = D &+ t1
+                D = C
+                C = B
+                B = A
+                A = t1 &+ t2
+            }
+            
+            hh[0] = (hh[0] &+ A)
+            hh[1] = (hh[1] &+ B)
+            hh[2] = (hh[2] &+ C)
+            hh[3] = (hh[3] &+ D)
+            hh[4] = (hh[4] &+ E)
+            hh[5] = (hh[5] &+ F)
+            hh[6] = (hh[6] &+ G)
+            hh[7] = (hh[7] &+ H)
+        }
+        
+        // Produce the final hash value (big-endian)
+        var result = [UInt8]()
+        result.reserveCapacity(hh.count / 4)
+        Self.resultingArray(hh).forEach {
+            let item = $0.bigEndian
+            var partialResult = [UInt8]()
+            partialResult.reserveCapacity(8)
+            for i in 0..<8 {
+                let shift = UInt64(8 * i)
+                partialResult.append(UInt8((item >> shift) & 0xff))
+            }
+            result += partialResult
+        }
+        return result
+    }
+}
+
+final class SHA256 : SHA2Variant32 {
+    static let size = 64
+    static let h: [UInt64] = [0x6a09e667, 0xbb67ae85, 0x3c6ef372, 0xa54ff53a, 0x510e527f, 0x9b05688c, 0x1f83d9ab, 0x5be0cd19]
+    static let k: [UInt64] = [0x428a2f98, 0x71374491, 0xb5c0fbcf, 0xe9b5dba5, 0x3956c25b, 0x59f111f1, 0x923f82a4, 0xab1c5ed5,
+                                     0xd807aa98, 0x12835b01, 0x243185be, 0x550c7dc3, 0x72be5d74, 0x80deb1fe, 0x9bdc06a7, 0xc19bf174,
+                                     0xe49b69c1, 0xefbe4786, 0x0fc19dc6, 0x240ca1cc, 0x2de92c6f, 0x4a7484aa, 0x5cb0a9dc, 0x76f988da,
+                                     0x983e5152, 0xa831c66d, 0xb00327c8, 0xbf597fc7, 0xc6e00bf3, 0xd5a79147, 0x06ca6351, 0x14292967,
+                                     0x27b70a85, 0x2e1b2138, 0x4d2c6dfc, 0x53380d13, 0x650a7354, 0x766a0abb, 0x81c2c92e, 0x92722c85,
+                                     0xa2bfe8a1, 0xa81a664b, 0xc24b8b70, 0xc76c51a3, 0xd192e819, 0xd6990624, 0xf40e3585, 0x106aa070,
+                                     0x19a4c116, 0x1e376c08, 0x2748774c, 0x34b0bcb5, 0x391c0cb3, 0x4ed8aa4a, 0x5b9cca4f, 0x682e6ff3,
+                                     0x748f82ee, 0x78a5636f, 0x84c87814, 0x8cc70208, 0x90befffa, 0xa4506ceb, 0xbef9a3f7, 0xc67178f2]
+    
+    static func resultingArray<T>(_ hh: [T]) -> ArraySlice<T> {
+        return ArraySlice(hh)
+    }
+}
+
+final class SHA384 : SHA2Variant64 {
+    static let size = 128
+    static let h: [UInt64] = [0xcbbb9d5dc1059ed8, 0x629a292a367cd507, 0x9159015a3070dd17, 0x152fecd8f70e5939, 0x67332667ffc00b31, 0x8eb44a8768581511, 0xdb0c2e0d64f98fa7, 0x47b5481dbefa4fa4]
+    static let k: [UInt64] = [0x428a2f98d728ae22, 0x7137449123ef65cd, 0xb5c0fbcfec4d3b2f, 0xe9b5dba58189dbbc, 0x3956c25bf348b538,
+                                     0x59f111f1b605d019, 0x923f82a4af194f9b, 0xab1c5ed5da6d8118, 0xd807aa98a3030242, 0x12835b0145706fbe,
+                                     0x243185be4ee4b28c, 0x550c7dc3d5ffb4e2, 0x72be5d74f27b896f, 0x80deb1fe3b1696b1, 0x9bdc06a725c71235,
+                                     0xc19bf174cf692694, 0xe49b69c19ef14ad2, 0xefbe4786384f25e3, 0x0fc19dc68b8cd5b5, 0x240ca1cc77ac9c65,
+                                     0x2de92c6f592b0275, 0x4a7484aa6ea6e483, 0x5cb0a9dcbd41fbd4, 0x76f988da831153b5, 0x983e5152ee66dfab,
+                                     0xa831c66d2db43210, 0xb00327c898fb213f, 0xbf597fc7beef0ee4, 0xc6e00bf33da88fc2, 0xd5a79147930aa725,
+                                     0x06ca6351e003826f, 0x142929670a0e6e70, 0x27b70a8546d22ffc, 0x2e1b21385c26c926, 0x4d2c6dfc5ac42aed,
+                                     0x53380d139d95b3df, 0x650a73548baf63de, 0x766a0abb3c77b2a8, 0x81c2c92e47edaee6, 0x92722c851482353b,
+                                     0xa2bfe8a14cf10364, 0xa81a664bbc423001, 0xc24b8b70d0f89791, 0xc76c51a30654be30, 0xd192e819d6ef5218,
+                                     0xd69906245565a910, 0xf40e35855771202a, 0x106aa07032bbd1b8, 0x19a4c116b8d2d0c8, 0x1e376c085141ab53,
+                                     0x2748774cdf8eeb99, 0x34b0bcb5e19b48a8, 0x391c0cb3c5c95a63, 0x4ed8aa4ae3418acb, 0x5b9cca4f7763e373,
+                                     0x682e6ff3d6b2b8a3, 0x748f82ee5defb2fc, 0x78a5636f43172f60, 0x84c87814a1f0ab72, 0x8cc702081a6439ec,
+                                     0x90befffa23631e28, 0xa4506cebde82bde9, 0xbef9a3f7b2c67915, 0xc67178f2e372532b, 0xca273eceea26619c,
+                                     0xd186b8c721c0c207, 0xeada7dd6cde0eb1e, 0xf57d4f7fee6ed178, 0x06f067aa72176fba, 0x0a637dc5a2c898a6,
+                                     0x113f9804bef90dae, 0x1b710b35131c471b, 0x28db77f523047d84, 0x32caab7b40c72493, 0x3c9ebe0a15c9bebc,
+                                     0x431d67c49c100d4c, 0x4cc5d4becb3e42b6, 0x597f299cfc657e2a, 0x5fcb6fab3ad6faec, 0x6c44198c4a475817]
+    
+    public static func resultingArray<T>(_ hh: [T]) -> ArraySlice<T> {
+        return hh[0..<6]
+    }
+}
+
+final class SHA512 : SHA2Variant64 {
+    static let size = 128
+    static let h: [UInt64] = [0x6a09e667f3bcc908, 0xbb67ae8584caa73b, 0x3c6ef372fe94f82b, 0xa54ff53a5f1d36f1, 0x510e527fade682d1, 0x9b05688c2b3e6c1f, 0x1f83d9abfb41bd6b, 0x5be0cd19137e2179]
+    static let k: [UInt64] = [0x428a2f98d728ae22, 0x7137449123ef65cd, 0xb5c0fbcfec4d3b2f, 0xe9b5dba58189dbbc, 0x3956c25bf348b538,
+                                     0x59f111f1b605d019, 0x923f82a4af194f9b, 0xab1c5ed5da6d8118, 0xd807aa98a3030242, 0x12835b0145706fbe,
+                                     0x243185be4ee4b28c, 0x550c7dc3d5ffb4e2, 0x72be5d74f27b896f, 0x80deb1fe3b1696b1, 0x9bdc06a725c71235,
+                                     0xc19bf174cf692694, 0xe49b69c19ef14ad2, 0xefbe4786384f25e3, 0x0fc19dc68b8cd5b5, 0x240ca1cc77ac9c65,
+                                     0x2de92c6f592b0275, 0x4a7484aa6ea6e483, 0x5cb0a9dcbd41fbd4, 0x76f988da831153b5, 0x983e5152ee66dfab,
+                                     0xa831c66d2db43210, 0xb00327c898fb213f, 0xbf597fc7beef0ee4, 0xc6e00bf33da88fc2, 0xd5a79147930aa725,
+                                     0x06ca6351e003826f, 0x142929670a0e6e70, 0x27b70a8546d22ffc, 0x2e1b21385c26c926, 0x4d2c6dfc5ac42aed,
+                                     0x53380d139d95b3df, 0x650a73548baf63de, 0x766a0abb3c77b2a8, 0x81c2c92e47edaee6, 0x92722c851482353b,
+                                     0xa2bfe8a14cf10364, 0xa81a664bbc423001, 0xc24b8b70d0f89791, 0xc76c51a30654be30, 0xd192e819d6ef5218,
+                                     0xd69906245565a910, 0xf40e35855771202a, 0x106aa07032bbd1b8, 0x19a4c116b8d2d0c8, 0x1e376c085141ab53,
+                                     0x2748774cdf8eeb99, 0x34b0bcb5e19b48a8, 0x391c0cb3c5c95a63, 0x4ed8aa4ae3418acb, 0x5b9cca4f7763e373,
+                                     0x682e6ff3d6b2b8a3, 0x748f82ee5defb2fc, 0x78a5636f43172f60, 0x84c87814a1f0ab72, 0x8cc702081a6439ec,
+                                     0x90befffa23631e28, 0xa4506cebde82bde9, 0xbef9a3f7b2c67915, 0xc67178f2e372532b, 0xca273eceea26619c,
+                                     0xd186b8c721c0c207, 0xeada7dd6cde0eb1e, 0xf57d4f7fee6ed178, 0x06f067aa72176fba, 0x0a637dc5a2c898a6,
+                                     0x113f9804bef90dae, 0x1b710b35131c471b, 0x28db77f523047d84, 0x32caab7b40c72493, 0x3c9ebe0a15c9bebc,
+                                     0x431d67c49c100d4c, 0x4cc5d4becb3e42b6, 0x597f299cfc657e2a, 0x5fcb6fab3ad6faec, 0x6c44198c4a475817]
+    
+    static func resultingArray<T>(_ hh: [T]) -> ArraySlice<T> {
+        return ArraySlice(hh)
+    }
+}
+
+final class SHA2<Variant: SHA2Variant> {
+    static var size: Int {
+        return Variant.size
+    }
+    
+    static func calculate(_ message: [UInt8]) -> [UInt8] {
+        return Variant.calculate(message)
+    }
+}
+
+final class HMAC<Variant: SHA2Variant> {
+    public static func authenticate(message:[UInt8], withKey key: [UInt8]) -> [UInt8] {
+        var key = key
+        
+        if (key.count > Variant.size) {
+            key = Variant.calculate(key)
+        }
+        
+        if (key.count < Variant.size) { // keys shorter than blocksize are zero-padded
+            key = key + [UInt8](repeating: 0, count: Variant.size - key.count)
+        }
+        
+        var opad = [UInt8](repeating: 0x5c, count: Variant.size)
+        for (idx, _) in key.enumerated() {
+            opad[idx] = key[idx] ^ opad[idx]
+        }
+        var ipad = [UInt8](repeating: 0x36, count: Variant.size)
+        for (idx, _) in key.enumerated() {
+            ipad[idx] = key[idx] ^ ipad[idx]
+        }
+        
+        let ipadAndMessageHash = Variant.calculate(ipad + message)
+        let finalHash = Variant.calculate(opad + ipadAndMessageHash);
+        
+        return finalHash
+    }
+    
+    static func authenticate(message: String, withKey key: [UInt8]) -> [UInt8] {
+        return authenticate(message: [UInt8](message.utf8), withKey: key)
+    }
+    
+    static func authenticate(message: Data, withKey key: Data) -> Data {
+        return Data(bytes: authenticate(message: Array(message), withKey: Array(key)))
+    }
+    
+    static func authenticate(message: String, withKey key: Data) -> Data {
+        return Data(bytes: authenticate(message: [UInt8](message.utf8), withKey: Array(key)))
+    }
+}
+
+fileprivate struct BytesSequence: Sequence {
+    let chunkSize: Int
+    let data: [UInt8]
+    
+    init(chunkSize: Int, data: [UInt8]) {
+        self.chunkSize = chunkSize
+        self.data = data
+    }
+    
+    func makeIterator() -> AnyIterator<ArraySlice<UInt8>> {
+        var offset:Int = 0
+        
+        return AnyIterator {
+            let end = Swift.min(self.chunkSize, self.data.count - offset)
+            let result = self.data[offset..<offset + end]
+            offset += result.count
+            return result.count > 0 ? result : nil
+        }
+    }
+}
+
+fileprivate func rotateRight(_ x:UInt16, n:UInt16) -> UInt16 {
+    return (x >> n) | (x << (16 - n))
+}
+
+fileprivate func rotateRight(_ x:UInt32, n:UInt32) -> UInt32 {
+    return (x >> n) | (x << (32 - n))
+}
+
+fileprivate func rotateRight(_ x:UInt64, n:UInt64) -> UInt64 {
+    return ((x >> n) | (x << (64 - n)))
+}
+
+fileprivate func toUInt32Array(_ slice: ArraySlice<UInt8>) -> Array<UInt32> {
+    var result = Array<UInt32>()
+    result.reserveCapacity(16)
+    
+    for idx in stride(from: slice.startIndex, to: slice.endIndex, by: MemoryLayout<UInt32>.size) {
+        let val1:UInt32 = (UInt32(slice[idx.advanced(by: 3)]) << 24)
+        let val2:UInt32 = (UInt32(slice[idx.advanced(by: 2)]) << 16)
+        let val3:UInt32 = (UInt32(slice[idx.advanced(by: 1)]) << 8)
+        let val4:UInt32 = UInt32(slice[idx])
+        let val:UInt32 = val1 | val2 | val3 | val4
+        result.append(val)
+    }
+    return result
+}
+
+fileprivate func toUInt64Array(_ slice: ArraySlice<UInt8>) -> Array<UInt64> {
+    var result = Array<UInt64>()
+    result.reserveCapacity(32)
+    for idx in stride(from: slice.startIndex, to: slice.endIndex, by: MemoryLayout<UInt64>.size) {
+        var val:UInt64 = 0
+        val |= UInt64(slice[idx.advanced(by: 7)]) << 56
+        val |= UInt64(slice[idx.advanced(by: 6)]) << 48
+        val |= UInt64(slice[idx.advanced(by: 5)]) << 40
+        val |= UInt64(slice[idx.advanced(by: 4)]) << 32
+        val |= UInt64(slice[idx.advanced(by: 3)]) << 24
+        val |= UInt64(slice[idx.advanced(by: 2)]) << 16
+        val |= UInt64(slice[idx.advanced(by: 1)]) << 8
+        val |= UInt64(slice[idx.advanced(by: 0)]) << 0
+        result.append(val)
+    }
+    return result
+}
+
+fileprivate func arrayOfBytes<T>(_ value:T, length:Int? = nil) -> [UInt8] {
+    let totalBytes = length ?? MemoryLayout<T>.size
+    
+    let valuePointer = UnsafeMutablePointer<T>.allocate(capacity: 1)
+    
+    valuePointer.pointee = value
+    
+    let bytesPointer = UnsafeMutableRawPointer(valuePointer).assumingMemoryBound(to: UInt8.self)
+    var bytes = [UInt8](repeating: 0, count: totalBytes)
+    for j in 0..<min(MemoryLayout<T>.size,totalBytes) {
+        bytes[totalBytes - 1 - j] = (bytesPointer + j).pointee
+    }
+    
+    valuePointer.deinitialize()
+    valuePointer.deallocate(capacity: 1)
+    
+    return bytes
+}
+
+public extension String {
+    public func fp_sha256() -> [UInt8] {
+        return SHA2<SHA256>.calculate([UInt8](self.utf8))
+    }
+    
+    public func fp_sha384() -> [UInt8] {
+        return SHA2<SHA384>.calculate([UInt8](self.utf8))
+    }
+    
+    public func fp_sha512() -> [UInt8] {
+        return SHA2<SHA512>.calculate([UInt8](self.utf8))
+    }
+}
+
+public extension Data {
+    public func fp_sha256() -> [UInt8] {
+        return SHA2<SHA256>.calculate(Array(self))
+    }
+    
+    public func fp_sha384() -> [UInt8] {
+        return SHA2<SHA384>.calculate(Array(self))
+    }
+    
+    public func fp_sha512() -> [UInt8] {
+        return SHA2<SHA512>.calculate(Array(self))
+    }
+}
@@ -505,7 +505,6 @@ public class FileProviderStreamTask: URLSessionTask, StreamDelegate {
            return
        }
        
-        
        operation_queue.addOperation {
            self.dataToBeSent.append(data)
            let result = self.write(timeout: timeout, close: false)
@@ -12,7 +12,7 @@ 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 FTPFileProvider: FileProviderBasicRemote, FileProviderOperations, FileProviderReadWrite {
    open class var type: String { return "FTP" }
    open let baseURL: URL?
    open var currentPath: String
@@ -161,7 +161,7 @@ open class FTPFileProvider: FileProviderBasicRemote {
     
     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 path: path to target directory. If empty, root will be iterated.
     - 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.
@@ -216,7 +216,7 @@ open class FTPFileProvider: FileProviderBasicRemote {
     
     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 path: path to target directory. If empty, attributes of root will be returned.
     - 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.
@@ -281,27 +281,44 @@ open class FTPFileProvider: FileProviderBasicRemote {
    
    open func searchFiles(path: String, recursive: Bool, query: NSPredicate, foundItemHandler: ((FileObject) -> Void)?, completionHandler: @escaping ((_ files: [FileObject], _ error: Error?) -> Void)) -> Progress? {
        let progress = Progress(parent: nil, userInfo: nil)
-        _ = self.recursiveList(path: path, useMLST: true, foundItemsHandler: { items in
-            if let foundItemHandler = foundItemHandler {
-                for item in items where query.evaluate(with: item.mapPredicate()) {
-                    foundItemHandler(item)
+        if recursive {
+            return self.recursiveList(path: path, useMLST: true, foundItemsHandler: { items in
+                if let foundItemHandler = foundItemHandler {
+                    for item in items where query.evaluate(with: item.mapPredicate()) {
+                        foundItemHandler(item)
+                    }
+                    progress.totalUnitCount = Int64(items.count)
                }
-                progress.totalUnitCount = Int64(items.count)
-            }
-        }, completionHandler: {files, error in
-            if let error = error {
-                completionHandler([], error)
-                return
-            }
-            
-            let foundFiles = files.filter { query.evaluate(with: $0.mapPredicate()) }
-            completionHandler(foundFiles, nil)
-        })
+            }, completionHandler: {files, error in
+                if let error = error {
+                    completionHandler([], error)
+                    return
+                }
+                
+                let foundFiles = files.filter { query.evaluate(with: $0.mapPredicate()) }
+                completionHandler(foundFiles, nil)
+            })
+        } else {
+            self.contentsOfDirectory(path: path, completionHandler: { (items, error) in
+                if let error = error {
+                    completionHandler([], error)
+                    return
+                }
+                
+                var result = [FileObject]()
+                for item in items where query.evaluate(with: item.mapPredicate()) {
+                    foundItemHandler?(item)
+                    result.append(item)
+                }
+                completionHandler(result, nil)
+            })
+        }
+        
        return progress
    }
    
-    public func url(of path: String?) -> URL {
-        let path = (path ?? self.currentPath).trimmingCharacters(in: CharacterSet(charactersIn: "/ ")).addingPercentEncoding(withAllowedCharacters: .urlPathAllowed) ?? (path ?? self.currentPath)
+    open func url(of path: String?) -> URL {
+        let path = (path ?? self.currentPath).trimmingCharacters(in: CharacterSet(charactersIn: "/ ")).addingPercentEncoding(withAllowedCharacters: .filePathAllowed) ?? (path ?? self.currentPath)
        
        var baseUrlComponent = URLComponents(url: self.baseURL!, resolvingAgainstBaseURL: true)
        baseUrlComponent?.user = credential?.user
@@ -309,7 +326,7 @@ open class FTPFileProvider: FileProviderBasicRemote {
        return URL(string: path, relativeTo: baseUrlComponent?.url ?? baseURL) ?? baseUrlComponent?.url ?? baseURL!
    }
    
-    public func relativePathOf(url: URL) -> String {
+    open func relativePathOf(url: URL) -> String {
        // check if url derieved from current base url
        let relativePath = url.relativePath
        if !relativePath.isEmpty, url.baseURL == self.baseURL {
@@ -330,9 +347,7 @@ open class FTPFileProvider: FileProviderBasicRemote {
    }
    
    open weak var fileOperationDelegate: FileOperationDelegate?
-}
-
-extension FTPFileProvider: FileProviderOperations {
+    
    open func create(folder folderName: String, at atPath: String, completionHandler: SimpleCompletionHandler) -> Progress? {
        let path = (atPath as NSString).appendingPathComponent(folderName) + "/"
        return doOperation(.create(path: path), completionHandler: completionHandler)
@@ -350,210 +365,6 @@ extension FTPFileProvider: FileProviderOperations {
        return doOperation(.remove(path: path), completionHandler: completionHandler)
    }
    
-    fileprivate func doOperation(_ opType: FileOperationType, completionHandler: SimpleCompletionHandler) -> Progress? {
-        guard fileOperationDelegate?.fileProvider(self, shouldDoOperation: opType) ?? true == true else {
-            return nil
-        }
-        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 progress = Progress(totalUnitCount: 1)
-        progress.setUserInfoObject(opType, forKey: .fileProvderOperationTypeKey)
-        progress.kind = .file
-        progress.setUserInfoObject(Progress.FileOperationKind.downloading, forKey: .fileOperationKindKey)
-        
-        let task = session.fpstreamTask(withHostName: baseURL!.host!, port: baseURL!.port!)
-        self.ftpLogin(task) { (error) in
-            if let error = error {
-                self.dispatch_queue.async {
-                    completionHandler?(error)
-                    self.delegateNotify(opType, error: error)
-                }
-                return
-            }
-            
-            self.execute(command: command, on: task, completionHandler: { (response, error) in
-                if let error = error {
-                    self.dispatch_queue.async {
-                        completionHandler?(error)
-                        self.delegateNotify(opType, error: error)
-                    }
-                    return
-                }
-                
-                guard let response = response else {
-                    self.dispatch_queue.async {
-                        completionHandler?(error)
-                        self.delegateNotify(opType, error: self.throwError(sourcePath, code: URLError.badServerResponse))
-                    }
-                    return
-                }
-                
-                let codes: [Int] = response.components(separatedBy: .newlines).flatMap({ $0.isEmpty ? nil : $0})
-                .flatMap {
-                    let code = $0.components(separatedBy: .whitespaces).flatMap({ $0.isEmpty ? nil : $0}).first
-                    return code != nil ? Int(code!) : nil
-                }
-                
-                if codes.filter({ (450..<560).contains($0) }).count > 0 {
-                    let errorCode: URLError.Code
-                    switch opType {
-                    case .create:
-                        errorCode = URLError.cannotCreateFile
-                    case .modify:
-                        errorCode = URLError.cannotWriteToFile
-                    case .copy:
-                        self.fallbackCopy(opType, progress: progress, completionHandler: completionHandler)
-                        return
-                    case .move:
-                        errorCode = URLError.cannotMoveFile
-                    case .remove:
-                        self.fallbackRemove(opType, progress: progress, on: task, completionHandler: completionHandler)
-                        return
-                    case .link:
-                        errorCode = URLError.cannotWriteToFile
-                    default:
-                        errorCode = URLError.cannotOpenFile
-                    }
-                    let error = self.throwError(sourcePath, code: errorCode)
-                    progress.cancel()
-                    self.dispatch_queue.async {
-                        completionHandler?(error)
-                    }
-                    self.delegateNotify(opType, error: error)
-                    return
-                }
-                
-                progress.completedUnitCount = progress.totalUnitCount
-                self.dispatch_queue.async {
-                    completionHandler?(nil)
-                }
-                self.delegateNotify(opType, error: nil)
-            })
-        }
-        
-        progress.cancellationHandler = { [weak task] in
-            task?.cancel()
-        }
-        progress.setUserInfoObject(Date(), forKey: .startingTimeKey)
-        return progress
-    }
-    
-    private func fallbackCopy(_ opType: FileOperationType, progress: Progress, completionHandler: SimpleCompletionHandler) {
-        guard let sourcePath = opType.source else { return }
-        guard let destPath = opType.destination else { return }
-        
-        let localURL = URL(fileURLWithPath: NSTemporaryDirectory()).appendingPathComponent(UUID().uuidString).appendingPathExtension("tmp")
-        
-        progress.becomeCurrent(withPendingUnitCount: 1)
-        _ = self.copyItem(path: sourcePath, toLocalURL: localURL) { (error) in
-            if let error = error {
-                self.dispatch_queue.async {
-                    completionHandler?(error)
-                    self.delegateNotify(opType, error: error)
-                }
-                return
-            }
-            
-            progress.becomeCurrent(withPendingUnitCount: 1)
-            _ = self.copyItem(localFile: localURL, to: destPath) { error in
-                completionHandler?(nil)
-                self.delegateNotify(opType, error: nil)
-            }
-            progress.resignCurrent()
-        }
-        progress.resignCurrent()
-        return
-    }
-    
-    private func fallbackRemove(_ opType: FileOperationType, progress: Progress, on task: FileProviderStreamTask, completionHandler: SimpleCompletionHandler) {
-        guard let sourcePath = opType.source else { return }
-        
-        self.execute(command: "SITE RMDIR \(ftpPath(sourcePath))", on: task) { (response, error) in
-            if let error = error {
-                progress.cancel()
-                self.dispatch_queue.async {
-                    completionHandler?(error)
-                }
-                self.delegateNotify(opType, error: error)
-                return
-            }
-            
-            guard let response = response else {
-                progress.cancel()
-                let error = self.throwError(sourcePath, code: URLError.badServerResponse)
-                self.dispatch_queue.async {
-                    completionHandler?(error)
-                }
-                self.delegateNotify(opType, error: error)
-                return
-            }
-            
-            if response.hasPrefix("50") {
-                self.fallbackRecursiveRemove(opType, progress: progress, on: task, completionHandler: completionHandler)
-                return
-            }
-            
-            var error: Error?
-            if !response.hasPrefix("2") {
-                error = self.throwError(sourcePath, code: URLError.cannotRemoveFile)
-            }
-            self.dispatch_queue.async {
-                completionHandler?(error)
-            }
-            self.delegateNotify(opType, error: error)
-        }
-    }
-    
-    private func fallbackRecursiveRemove(_ opType: FileOperationType, progress: Progress, on task: FileProviderStreamTask, completionHandler: SimpleCompletionHandler) {
-        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 recursiveProgress = Progress(parent: progress, userInfo: nil)
-            recursiveProgress.totalUnitCount = Int64(contents.count)
-            let sortedContents = contents.sorted(by: {
-                $0.path.localizedStandardCompare($1.path) == .orderedDescending
-            })
-            var command = ""
-            for file in sortedContents {
-                command += (file.isDirectory ? "RMD \(self.ftpPath(file.path))" : "DELE \(self.ftpPath(file.path))") + "\r\n"
-            }
-            command += "RMD \(self.ftpPath(sourcePath))"
-            
-            self.execute(command: command, on: task, completionHandler: { (response, error) in
-                recursiveProgress.completedUnitCount += 1
-                self.dispatch_queue.async {
-                    completionHandler?(error)
-                    self.delegateNotify(opType, error: error)
-                }
-                // TODO: Digest response
-            })
-        })
-    }
-    
    open func copyItem(localFile: URL, to toPath: String, overwrite: Bool, completionHandler: SimpleCompletionHandler) -> Progress? {
        // check file is not a folder
        guard (try? localFile.resourceValues(forKeys: [.fileResourceTypeKey]))?.fileResourceType ?? .unknown == .regular else {
@@ -563,13 +374,13 @@ extension FTPFileProvider: FileProviderOperations {
            return nil
        }
        
-        let opType = FileOperationType.copy(source: localFile.absoluteString, destination: toPath)
-        guard fileOperationDelegate?.fileProvider(self, shouldDoOperation: opType) ?? true == true else {
+        let operation = FileOperationType.copy(source: localFile.absoluteString, destination: toPath)
+        guard fileOperationDelegate?.fileProvider(self, shouldDoOperation: operation) ?? true == true else {
            return nil
        }
        
        let progress = Progress(totalUnitCount: 0)
-        progress.setUserInfoObject(opType, forKey: .fileProvderOperationTypeKey)
+        progress.setUserInfoObject(operation, forKey: .fileProvderOperationTypeKey)
        progress.kind = .file
        progress.setUserInfoObject(Progress.FileOperationKind.downloading, forKey: .fileOperationKindKey)
        
@@ -578,7 +389,7 @@ extension FTPFileProvider: FileProviderOperations {
            if let error = error {
                self.dispatch_queue.async {
                    completionHandler?(error)
-                    self.delegateNotify(opType, error: error)
+                    self.delegateNotify(operation, error: error)
                }
                return
            }
@@ -591,9 +402,7 @@ extension FTPFileProvider: FileProviderOperations {
                progress.setUserInfoObject(Date(), forKey: .startingTimeKey)
            }, onProgress: { bytesSent, totalSent, expectedBytes in
                progress.completedUnitCount = totalSent
-                DispatchQueue.main.async {
-                    self.delegate?.fileproviderProgress(self, operation: opType, progress: Float(progress.fractionCompleted))
-                }
+                self.delegateNotify(operation, progress: progress.fractionCompleted)
            }, completionHandler: { (error) in
                if error != nil {
                    progress.cancel()
@@ -601,7 +410,7 @@ extension FTPFileProvider: FileProviderOperations {
                self.ftpQuit(task)
                self.dispatch_queue.async {
                    completionHandler?(error)
-                    self.delegateNotify(opType, error: error)
+                    self.delegateNotify(operation, error: error)
                }
            })
        }
@@ -610,12 +419,12 @@ extension FTPFileProvider: FileProviderOperations {
    }
    
    open func copyItem(path: String, toLocalURL destURL: URL, completionHandler: SimpleCompletionHandler) -> Progress? {
-        let opType = FileOperationType.copy(source: path, destination: destURL.absoluteString)
-        guard fileOperationDelegate?.fileProvider(self, shouldDoOperation: opType) ?? true == true else {
+        let operation = FileOperationType.copy(source: path, destination: destURL.absoluteString)
+        guard fileOperationDelegate?.fileProvider(self, shouldDoOperation: operation) ?? true == true else {
            return nil
        }
        var progress = Progress(totalUnitCount: 0)
-        progress.setUserInfoObject(opType, forKey: .fileProvderOperationTypeKey)
+        progress.setUserInfoObject(operation, forKey: .fileProvderOperationTypeKey)
        progress.kind = .file
        progress.setUserInfoObject(Progress.FileOperationKind.downloading, forKey: .fileOperationKindKey)
        
@@ -624,7 +433,7 @@ extension FTPFileProvider: FileProviderOperations {
                if let error = error {
                    self.dispatch_queue.async {
                        completionHandler?(error)
-                        self.delegateNotify(opType, error: error)
+                        self.delegateNotify(operation, error: error)
                    }
                    return
                }
@@ -633,7 +442,7 @@ extension FTPFileProvider: FileProviderOperations {
                    self.dispatch_queue.async {
                        let error = self.throwError(path, code: URLError.fileIsDirectory)
                        completionHandler?(error)
-                        self.delegateNotify(opType, error: error)
+                        self.delegateNotify(operation, error: error)
                    }
                    return
                }
@@ -650,7 +459,7 @@ extension FTPFileProvider: FileProviderOperations {
                        completionHandler?(e)
                    }
                }
-                task.taskDescription = opType.json
+                task.taskDescription = operation.json
                task.addObserver(self.sessionDelegate!, forKeyPath: #keyPath(URLSessionTask.countOfBytesReceived), options: .new, context: &progress)
                task.addObserver(self.sessionDelegate!, forKeyPath: #keyPath(URLSessionTask.countOfBytesExpectedToReceive), options: .new, context: &progress)
                progress.cancellationHandler = { [weak task] in
@@ -678,15 +487,13 @@ extension FTPFileProvider: FileProviderOperations {
                }, onProgress: { recevied, totalReceived, totalSize in
                    progress.totalUnitCount = totalSize
                    progress.completedUnitCount = totalReceived
-                    DispatchQueue.main.async {
-                        self.delegate?.fileproviderProgress(self, operation: opType, progress: Float(progress.fractionCompleted))
-                    }
+                    self.delegateNotify(operation, progress: progress.fractionCompleted)
                }) { (tmpurl, error) in
                    if let error = error {
                        progress.cancel()
                        self.dispatch_queue.async {
                            completionHandler?(error)
-                            self.delegateNotify(opType, error: error)
+                            self.delegateNotify(operation, error: error)
                        }
                        return
                    }
@@ -695,7 +502,7 @@ extension FTPFileProvider: FileProviderOperations {
                        try? FileManager.default.moveItem(at: tmpurl, to: destURL)
                        self.dispatch_queue.async {
                            completionHandler?(nil)
-                            self.delegateNotify(opType, error: nil)
+                            self.delegateNotify(operation)
                        }
                    }
                }
@@ -703,18 +510,16 @@ extension FTPFileProvider: FileProviderOperations {
        }
        return progress
    }
-}
-
-extension FTPFileProvider: FileProviderReadWrite {
+    
    open func contents(path: String, completionHandler: @escaping ((Data?, Error?) -> Void)) -> Progress? {
-        let opType = FileOperationType.fetch(path: path)
-        guard fileOperationDelegate?.fileProvider(self, shouldDoOperation: opType) ?? true == true else {
+        let operation = FileOperationType.fetch(path: path)
+        guard fileOperationDelegate?.fileProvider(self, shouldDoOperation: operation) ?? true == true else {
            return nil
        }
        
        if self.useAppleImplementation {
            var progress = Progress(totalUnitCount: 0)
-            progress.setUserInfoObject(opType, forKey: .fileProvderOperationTypeKey)
+            progress.setUserInfoObject(operation, forKey: .fileProvderOperationTypeKey)
            progress.kind = .file
            progress.setUserInfoObject(Progress.FileOperationKind.downloading, forKey: .fileOperationKindKey)
            
@@ -733,7 +538,7 @@ extension FTPFileProvider: FileProviderReadWrite {
                    completionHandler(nil, e)
                }
            }
-            task.taskDescription = opType.json
+            task.taskDescription = operation.json
            task.addObserver(sessionDelegate!, forKeyPath: #keyPath(URLSessionTask.countOfBytesReceived), options: .new, context: &progress)
            task.addObserver(sessionDelegate!, forKeyPath: #keyPath(URLSessionTask.countOfBytesExpectedToReceive), options: .new, context: &progress)
            progress.cancellationHandler = { [weak task] in
@@ -748,16 +553,16 @@ extension FTPFileProvider: FileProviderReadWrite {
    }
    
    open func contents(path: String, offset: Int64, length: Int, completionHandler: @escaping ((_ contents: Data?, _ error: Error?) -> Void)) -> Progress? {
-        let opType = FileOperationType.fetch(path: path)
+        let operation = FileOperationType.fetch(path: path)
        if length == 0 || offset < 0 {
            dispatch_queue.async {
                completionHandler(Data(), nil)
-                self.delegateNotify(opType, error: nil)
+                self.delegateNotify(operation)
            }
            return nil
        }
        let progress = Progress(totalUnitCount: 0)
-        progress.setUserInfoObject(opType, forKey: .fileProvderOperationTypeKey)
+        progress.setUserInfoObject(operation, forKey: .fileProvderOperationTypeKey)
        progress.kind = .file
        progress.setUserInfoObject(Progress.FileOperationKind.downloading, forKey: .fileOperationKindKey)
        
@@ -779,15 +584,13 @@ extension FTPFileProvider: FileProviderReadWrite {
            }, onProgress: { recevied, totalReceived, totalSize in
                progress.totalUnitCount = totalSize
                progress.completedUnitCount = totalReceived
-                DispatchQueue.main.async {
-                    self.delegate?.fileproviderProgress(self, operation: opType, progress: Float(progress.fractionCompleted))
-                }
+                self.delegateNotify(operation, progress: progress.fractionCompleted)
            }) { (data, error) in
                if let error = error {
                    progress.cancel()
                    self.dispatch_queue.async {
                        completionHandler(nil, error)
-                        self.delegateNotify(opType, error: error)
+                        self.delegateNotify(operation, error: error)
                    }
                    return
                }
@@ -795,7 +598,7 @@ extension FTPFileProvider: FileProviderReadWrite {
                if let data = data {
                    self.dispatch_queue.async {
                        completionHandler(data, nil)
-                        self.delegateNotify(opType, error: nil)
+                        self.delegateNotify(operation)
                    }
                }
            }
@@ -805,13 +608,13 @@ extension FTPFileProvider: FileProviderReadWrite {
    }
    
    open func writeContents(path: String, contents data: Data?, atomically: Bool, overwrite: Bool, completionHandler: SimpleCompletionHandler) -> Progress? {
-        let opType = FileOperationType.modify(path: path)
-        guard fileOperationDelegate?.fileProvider(self, shouldDoOperation: opType) ?? true == true else {
+        let operation = FileOperationType.modify(path: path)
+        guard fileOperationDelegate?.fileProvider(self, shouldDoOperation: operation) ?? true == true else {
            return nil
        }
        
        let progress = Progress(totalUnitCount: Int64(data?.count ?? 0))
-        progress.setUserInfoObject(opType, forKey: .fileProvderOperationTypeKey)
+        progress.setUserInfoObject(operation, forKey: .fileProvderOperationTypeKey)
        progress.kind = .file
        progress.setUserInfoObject(Progress.FileOperationKind.downloading, forKey: .fileOperationKindKey)
        
@@ -820,7 +623,7 @@ extension FTPFileProvider: FileProviderReadWrite {
            if let error = error {
                self.dispatch_queue.async {
                    completionHandler?(error)
-                    self.delegateNotify(opType, error: error)
+                    self.delegateNotify(operation, error: error)
                }
                return
            }
@@ -834,9 +637,7 @@ extension FTPFileProvider: FileProviderReadWrite {
                    progress.setUserInfoObject(Date(), forKey: .startingTimeKey)
                }, onProgress: { bytesSent, totalSent, expectedBytes in
                    progress.completedUnitCount = totalSent
-                    DispatchQueue.main.async {
-                        self.delegate?.fileproviderProgress(self, operation: opType, progress: Float(progress.fractionCompleted))
-                    }
+                    self.delegateNotify(operation, progress: progress.fractionCompleted)
                }, completionHandler: { (error) in
                    if error != nil {
                        progress.cancel()
@@ -844,7 +645,7 @@ extension FTPFileProvider: FileProviderReadWrite {
                    self.ftpQuit(task)
                    self.dispatch_queue.async {
                        completionHandler?(error)
-                        self.delegateNotify(opType, error: error)
+                        self.delegateNotify(operation, error: error)
                    }
                })
            }
@@ -862,9 +663,7 @@ extension FTPFileProvider: FileProviderReadWrite {
        
        return progress
    }
-}
-
-public extension FTPFileProvider {
+    
    /**
     Creates a symbolic link at the specified path that points to an item at the given path.
     This method does not traverse symbolic links contained in destination path, making it possible
@@ -878,9 +677,217 @@ public extension FTPFileProvider {
       - 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)
+    open func create(symbolicLink path: String, withDestinationPath destPath: String, completionHandler: SimpleCompletionHandler) {
+        let operation = FileOperationType.link(link: path, target: destPath)
+        _=self.doOperation(operation, completionHandler: completionHandler)
+    }
+}
+
+extension FTPFileProvider {
+    fileprivate func doOperation(_ operation: FileOperationType, completionHandler: SimpleCompletionHandler) -> Progress? {
+        guard fileOperationDelegate?.fileProvider(self, shouldDoOperation: operation) ?? true == true else {
+            return nil
+        }
+        let sourcePath = operation.source
+        let destPath = operation.destination
+        
+        let command: String
+        switch operation {
+        case .create:
+            command = "MKD \(ftpPath(sourcePath))"
+        case .copy:
+            command = "SITE CPFR \(ftpPath(sourcePath))\r\nSITE CPTO \(ftpPath(destPath!))"
+        case .move:
+            command = "RNFR \(ftpPath(sourcePath))\r\nRNTO \(ftpPath(destPath!))"
+        case .remove:
+            command = "DELE \(ftpPath(sourcePath))"
+        case .link:
+            command = "SITE SYMLINK \(ftpPath(sourcePath)) \(ftpPath(destPath!))"
+        default: // modify, fetch
+            return nil
+        }
+        let progress = Progress(totalUnitCount: 1)
+        progress.setUserInfoObject(operation, forKey: .fileProvderOperationTypeKey)
+        progress.kind = .file
+        progress.setUserInfoObject(Progress.FileOperationKind.downloading, forKey: .fileOperationKindKey)
+        
+        let task = session.fpstreamTask(withHostName: baseURL!.host!, port: baseURL!.port!)
+        self.ftpLogin(task) { (error) in
+            if let error = error {
+                self.dispatch_queue.async {
+                    completionHandler?(error)
+                    self.delegateNotify(operation, 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(operation, error: error)
+                    }
+                    return
+                }
+                
+                guard let response = response else {
+                    self.dispatch_queue.async {
+                        completionHandler?(error)
+                        self.delegateNotify(operation, 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 operation {
+                    case .create:
+                        errorCode = URLError.cannotCreateFile
+                    case .modify:
+                        errorCode = URLError.cannotWriteToFile
+                    case .copy:
+                        self.fallbackCopy(operation, progress: progress, completionHandler: completionHandler)
+                        return
+                    case .move:
+                        errorCode = URLError.cannotMoveFile
+                    case .remove:
+                        self.fallbackRemove(operation, progress: progress, on: task, completionHandler: completionHandler)
+                        return
+                    case .link:
+                        errorCode = URLError.cannotWriteToFile
+                    default:
+                        errorCode = URLError.cannotOpenFile
+                    }
+                    let error = self.throwError(sourcePath, code: errorCode)
+                    progress.cancel()
+                    self.dispatch_queue.async {
+                        completionHandler?(error)
+                    }
+                    self.delegateNotify(operation, error: error)
+                    return
+                }
+                
+                progress.completedUnitCount = progress.totalUnitCount
+                self.dispatch_queue.async {
+                    completionHandler?(nil)
+                }
+                self.delegateNotify(operation)
+            })
+        }
+        
+        progress.cancellationHandler = { [weak task] in
+            task?.cancel()
+        }
+        progress.setUserInfoObject(Date(), forKey: .startingTimeKey)
+        return progress
+    }
+    
+    private func fallbackCopy(_ operation: FileOperationType, progress: Progress, completionHandler: SimpleCompletionHandler) {
+        let sourcePath = operation.source
+        guard let destPath = operation.destination else { return }
+        
+        let localURL = URL(fileURLWithPath: NSTemporaryDirectory()).appendingPathComponent(UUID().uuidString).appendingPathExtension("tmp")
+        
+        progress.becomeCurrent(withPendingUnitCount: 1)
+        _ = self.copyItem(path: sourcePath, toLocalURL: localURL) { (error) in
+            if let error = error {
+                self.dispatch_queue.async {
+                    completionHandler?(error)
+                    self.delegateNotify(operation, error: error)
+                }
+                return
+            }
+            
+            progress.becomeCurrent(withPendingUnitCount: 1)
+            _ = self.copyItem(localFile: localURL, to: destPath) { error in
+                completionHandler?(nil)
+                self.delegateNotify(operation)
+            }
+            progress.resignCurrent()
+        }
+        progress.resignCurrent()
+        return
+    }
+    
+    private func fallbackRemove(_ operation: FileOperationType, progress: Progress, on task: FileProviderStreamTask, completionHandler: SimpleCompletionHandler) {
+        let sourcePath = operation.source
+        
+        self.execute(command: "SITE RMDIR \(ftpPath(sourcePath))", on: task) { (response, error) in
+            if let error = error {
+                progress.cancel()
+                self.dispatch_queue.async {
+                    completionHandler?(error)
+                }
+                self.delegateNotify(operation, error: error)
+                return
+            }
+            
+            guard let response = response else {
+                progress.cancel()
+                let error = self.throwError(sourcePath, code: URLError.badServerResponse)
+                self.dispatch_queue.async {
+                    completionHandler?(error)
+                }
+                self.delegateNotify(operation, error: error)
+                return
+            }
+            
+            if response.hasPrefix("50") {
+                self.fallbackRecursiveRemove(operation, progress: progress, on: task, completionHandler: completionHandler)
+                return
+            }
+            
+            var error: Error?
+            if !response.hasPrefix("2") {
+                error = self.throwError(sourcePath, code: URLError.cannotRemoveFile)
+            }
+            self.dispatch_queue.async {
+                completionHandler?(error)
+            }
+            self.delegateNotify(operation, error: error)
+        }
+    }
+    
+    private func fallbackRecursiveRemove(_ operation: FileOperationType, progress: Progress, on task: FileProviderStreamTask, completionHandler: SimpleCompletionHandler) {
+        let sourcePath = operation.source
+        
+        _ = self.recursiveList(path: sourcePath, useMLST: true, completionHandler: { (contents, error) in
+            if let error = error {
+                self.dispatch_queue.async {
+                    completionHandler?(error)
+                    self.delegateNotify(operation, error: error)
+                }
+                return
+            }
+            
+            progress.becomeCurrent(withPendingUnitCount: 1)
+            let recursiveProgress = Progress(parent: progress, userInfo: nil)
+            recursiveProgress.totalUnitCount = Int64(contents.count)
+            let sortedContents = contents.sorted(by: {
+                $0.path.localizedStandardCompare($1.path) == .orderedDescending
+            })
+            progress.resignCurrent()
+            var command = ""
+            for file in sortedContents {
+                command += (file.isDirectory ? "RMD \(self.ftpPath(file.path))" : "DELE \(self.ftpPath(file.path))") + "\r\n"
+            }
+            command += "RMD \(self.ftpPath(sourcePath))"
+            
+            self.execute(command: command, on: task, completionHandler: { (response, error) in
+                recursiveProgress.completedUnitCount += 1
+                self.dispatch_queue.async {
+                    completionHandler?(error)
+                    self.delegateNotify(operation, error: error)
+                }
+                // TODO: Digest response
+            })
+        })
    }
 }

@@ -9,16 +9,6 @@
 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 {
@@ -454,7 +444,7 @@ internal extension FTPFileProvider {
    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 {
+        if useCache, let url = URL(string: filePath.addingPercentEncoding(withAllowedCharacters: .filePathAllowed) ?? 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)
            }
@@ -514,7 +504,7 @@ internal extension FTPFileProvider {
                            }
                        }
                        
-                        if let url = URL(string: filePath.addingPercentEncoding(withAllowedCharacters: .urlPathAllowed) ?? filePath, relativeTo: self.baseURL!)?.absoluteURL {
+                        if let url = URL(string: filePath.addingPercentEncoding(withAllowedCharacters: .filePathAllowed) ?? 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)
@@ -552,7 +542,7 @@ internal extension FTPFileProvider {
        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 {
+        if useCache, let url = URL(string: filePath.addingPercentEncoding(withAllowedCharacters: .filePathAllowed) ?? 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)
@@ -619,7 +609,7 @@ internal extension FTPFileProvider {
                            }
                        }
                        
-                        if let url = URL(string: filePath.addingPercentEncoding(withAllowedCharacters: .urlPathAllowed) ?? filePath, relativeTo: self.baseURL!)?.absoluteURL {
+                        if let url = URL(string: filePath.addingPercentEncoding(withAllowedCharacters: .filePathAllowed) ?? 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)
@@ -33,7 +33,7 @@ open class FileObject: Equatable {
            if let url = allValues[.fileURLKey] as? URL {
                return url
            } else {
-                let path = self.path.addingPercentEncoding(withAllowedCharacters: .urlPathAllowed) ?? self.path
+                let path = self.path.addingPercentEncoding(withAllowedCharacters: .filePathAllowed) ?? self.path
                return URL(string: path) ?? URL(string: "/")!
            }
        }
@@ -29,7 +29,8 @@ public protocol FileProviderBasic: class, NSSecureCoding {
    /// The url of which paths should resolve against.
    var baseURL: URL? { get }
    
-    /// Current active path used in `contentsOfDirectory(path:completionHandler:)` method.
+    /// **DEPRECATED** Current active path used in `contentsOfDirectory(path:completionHandler:)` method.
+    @available(*, deprecated, message: "This property is redundant with almost no use internally.")
    var currentPath: String { get set }
    
    /**
@@ -64,7 +65,7 @@ public protocol FileProviderBasic: class, NSSecureCoding {
     
     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 path: path to target directory. If empty, root will be iterated.
     - 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.
@@ -76,7 +77,7 @@ public protocol FileProviderBasic: class, NSSecureCoding {
     
     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 path: path to target directory. If empty, attributes of root will be returned.
     - 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.
@@ -133,7 +134,7 @@ public protocol FileProviderBasic: class, NSSecureCoding {
     - Parameter path: Relative path of file or directory.
     - Returns: An url, can be used to access to file directly.
    */
-    func url(of path: String?) -> URL
+    func url(of path: String) -> URL
    
    
    /// Returns the relative path of url, wothout percent encoding. Even if url is absolute or
@@ -418,6 +419,24 @@ public extension FileProviderOperations {
    }
 }

+internal extension FileProviderOperations {
+    internal func delegateNotify(_ operation: FileOperationType, error: Error? = nil) {
+        DispatchQueue.main.async(execute: {
+            if let error = error {
+                self.delegate?.fileproviderFailed(self, operation: operation, error: error)
+            } else {
+                self.delegate?.fileproviderSucceed(self, operation: operation)
+            }
+        })
+    }
+    
+    internal func delegateNotify(_ operation: FileOperationType, progress: Double) {
+        DispatchQueue.main.async(execute: {
+            self.delegate?.fileproviderProgress(self, operation: operation, progress: Float(progress))
+        })
+    }
+}
+
 /// Defines method for fetching and modifying file contents
 public protocol FileProviderReadWrite: FileProviderBasic {
    /**
@@ -647,9 +666,9 @@ extension FileProviderBasic {
        #endif
    }
    
-    public func url(of path: String? = nil) -> URL {
-        var rpath: String = path ?? self.currentPath
-        rpath = rpath.addingPercentEncoding(withAllowedCharacters: .urlPathAllowed) ?? rpath
+    public func url(of path: String) -> URL {
+        var rpath: String = path
+        rpath = rpath.addingPercentEncoding(withAllowedCharacters: .filePathAllowed) ?? rpath
        if let baseURL = baseURL {
            if rpath.hasPrefix("/") {
                rpath.remove(at: rpath.startIndex)
@@ -695,8 +714,9 @@ extension FileProviderBasic {
    }
    
    /// Returns a file name supposed to be unique with adding numbers to end of file.
-    /// - Important: It's a synchronous method. Don't use it on matin thread.
+    /// - Important: It's a synchronous method. Don't use it on main thread.
    public func fileByUniqueName(_ filePath: String) -> String {
+        //assert(!Thread.isMainThread, "\(#function) is not recommended to be executed on Main Thread.")
        let fileUrl = URL(fileURLWithPath: filePath)
        let dirPath = fileUrl.deletingLastPathComponent().path 
        let fileName = fileUrl.deletingPathExtension().lastPathComponent
@@ -732,18 +752,14 @@ extension FileProviderBasic {
        return (dirPath as NSString).appendingPathComponent(finalFile)
    }
    
-    internal func throwError(_ path: String, code: FoundationErrorEnum) -> NSError {
+    internal func throwError(_ path: String, code: URLError.Code) -> Error {
        let fileURL = self.url(of: path)
-        let domain: String
-        switch code {
-        case is URLError:
-            fallthrough
-        case is URLError.Code:
-            domain = NSURLErrorDomain
-        default:
-            domain = NSCocoaErrorDomain
-        }
-        return NSError(domain: domain, code: code.rawValue, userInfo: [NSURLErrorFailingURLErrorKey: fileURL, NSURLErrorFailingURLStringErrorKey: fileURL.absoluteString])
+        return URLError(code, userInfo: [NSURLErrorKey: fileURL, NSURLErrorFailingURLErrorKey: fileURL, NSURLErrorFailingURLStringErrorKey: fileURL.absoluteString])
+    }
+    
+    internal func throwError(_ path: String, code: CocoaError.Code) -> Error {
+        let fileURL = self.url(of: path)
+        return CocoaError(code, userInfo: [NSFilePathErrorKey: path, NSURLErrorKey: fileURL])
    }
    
    internal func NotImplemented(_ fn: String = #function, file: StaticString = #file) {
@@ -956,10 +972,10 @@ public enum FileOperationType: CustomStringConvertible {
    }
    
    /// Path of subjecting file.
-    public var source: String? {
-        guard let reflect = Mirror(reflecting: self).children.first?.value else { return nil }
+    public var source: String {
+        let reflect = Mirror(reflecting: self).children.first!.value
        let mirror = Mirror(reflecting: reflect)
-        return reflect as? String ?? mirror.children.first?.value as? String
+        return reflect as? String ?? mirror.children.first?.value as! String
    }
    
    /// Path of subjecting file.
@@ -1041,7 +1057,7 @@ public protocol FileProviderDelegate: class {
    func fileproviderSucceed(_ fileProvider: FileProviderOperations, operation: FileOperationType)
    /// fileproviderSucceed(_:operation:) gives delegate a notification when an operation finished with failure.
    /// This method is called in main thread to avoids UI bugs.
-    func fileproviderFailed(_ fileProvider: FileProviderOperations, operation: FileOperationType)
+    func fileproviderFailed(_ fileProvider: FileProviderOperations, operation: FileOperationType, error: Error)
    /// fileproviderSucceed(_:operation:) gives delegate a notification when an operation progess.
    /// Supported by some providers, especially remote ones.
    /// This method is called in main thread to avoids UI bugs.
@@ -0,0 +1,392 @@
+//
+//  HTTPFileProvider.swift
+//  FilesProvider
+//
+//  Created by Amir Abbas Mousavian.
+//  Copyright © 2017 Mousavian. Distributed under MIT license.
+//
+
+import Foundation
+
+/**
+ The abstract base class for all REST/Web based providers such as WebDAV, Dropbox, OneDrive, Google Drive, etc. and encapsulates basic
+ functionalitis such as downloading/uploading.
+ 
+ No instance of this class should (and can) be created. Use derivated classes instead. It leads to a crash with `fatalError()`.
+ */
+open class HTTPFileProvider: FileProviderBasicRemote, FileProviderOperations, FileProviderReadWrite {
+    open class var type: String { fatalError("HTTPFileProvider is an abstract class. Please implement \(#function) in subclass.") }
+    open let baseURL: URL?
+    open var currentPath: String
+    
+    open var dispatch_queue: DispatchQueue
+    open var operation_queue: OperationQueue {
+        willSet {
+            assert(_session == nil, "It's not effective to change dispatch_queue property after session is initialized.")
+        }
+    }
+    
+    open weak var delegate: FileProviderDelegate?
+    open var credential: URLCredential? {
+        didSet {
+            sessionDelegate?.credential = self.credential
+        }
+    }
+    open private(set) var cache: URLCache?
+    public var useCache: Bool
+    public var validatingCache: Bool
+    
+    fileprivate var _session: URLSession?
+    internal fileprivate(set) var sessionDelegate: SessionDelegate?
+    public var session: URLSession {
+        get {
+            if _session == nil {
+                self.sessionDelegate = SessionDelegate(fileProvider: self)
+                let config = URLSessionConfiguration.default
+                config.urlCache = cache
+                config.requestCachePolicy = .returnCacheDataElseLoad
+                _session = URLSession(configuration: config, delegate: sessionDelegate as URLSessionDelegate?, delegateQueue: self.operation_queue)
+                _session!.sessionDescription = UUID().uuidString
+                initEmptySessionHandler(_session!.sessionDescription!)
+            }
+            return _session!
+        }
+        
+        set {
+            assert(newValue.delegate is SessionDelegate, "session instances should have a SessionDelegate instance as delegate.")
+            _session = newValue
+            if session.sessionDescription?.isEmpty ?? true {
+                _session?.sessionDescription = UUID().uuidString
+            }
+            self.sessionDelegate = newValue.delegate as? SessionDelegate
+            initEmptySessionHandler(_session!.sessionDescription!)
+        }
+    }
+    
+    fileprivate var _longpollSession: URLSession?
+    /// This session has extended timeout up to 10 minutes, suitable for monitoring.
+    internal var longpollSession: URLSession {
+        if _longpollSession == nil {
+            let config = URLSessionConfiguration.default
+            config.timeoutIntervalForRequest = 600
+            _longpollSession = URLSession(configuration: config, delegate: nil, delegateQueue: nil)
+        }
+        return _longpollSession!
+    }
+    
+    /**
+     This is parent initializer for subclasses. Using this method on `HTTPFileProvider` will fail as `type` is not implemented.
+     
+     - Parameters:
+     - baseURL: Location of WebDAV server.
+     - credential: An `URLCredential` object with `user` and `password`.
+     - cache: A URLCache to cache downloaded files and contents.
+     */
+    public init(baseURL: URL?, credential: URLCredential?, cache: URLCache?) {
+        self.baseURL = baseURL
+        self.currentPath = ""
+        self.useCache = false
+        self.validatingCache = true
+        self.cache = cache
+        self.credential = credential
+        
+        #if swift(>=3.1)
+            let queueLabel = "FileProvider.\(Swift.type(of: self).type)"
+        #else
+            let queueLabel = "FileProvider.\(type(of: self).type)"
+        #endif
+        dispatch_queue = DispatchQueue(label: queueLabel, attributes: .concurrent)
+        operation_queue = OperationQueue()
+        operation_queue.name = "\(queueLabel).Operation"
+    }
+    
+    public required convenience init?(coder aDecoder: NSCoder) {
+        fatalError("HTTPFileProvider is an abstract class. Please implement \(#function) in subclass.")
+    }
+    
+    public func encode(with aCoder: NSCoder) {
+        aCoder.encode(self.baseURL, forKey: "baseURL")
+        aCoder.encode(self.credential, forKey: "credential")
+        aCoder.encode(self.currentPath, forKey: "currentPath")
+        aCoder.encode(self.useCache, forKey: "useCache")
+        aCoder.encode(self.validatingCache, forKey: "validatingCache")
+    }
+    
+    public static var supportsSecureCoding: Bool {
+        return true
+    }
+    
+    open func copy(with zone: NSZone? = nil) -> Any {
+        fatalError("HTTPFileProvider is an abstract class. Please implement \(#function) in subclass.")
+    }
+    
+    deinit {
+        if let sessionuuid = _session?.sessionDescription {
+            removeSessionHandler(for: sessionuuid)
+        }
+        
+        if fileProviderCancelTasksOnInvalidating {
+            _session?.invalidateAndCancel()
+        } else {
+            _session?.finishTasksAndInvalidate()
+        }
+    }
+    
+    open func contentsOfDirectory(path: String, completionHandler: @escaping ((_ contents: [FileObject], _ error: Error?) -> Void)) {
+        fatalError("HTTPFileProvider is an abstract class. Please implement \(#function) in subclass.")
+    }
+    
+    open func attributesOfItem(path: String, completionHandler: @escaping ((_ attributes: FileObject?, _ error: Error?) -> Void)) {
+        fatalError("HTTPFileProvider is an abstract class. Please implement \(#function) in subclass.")
+    }
+    
+    open func storageProperties(completionHandler: @escaping ((_ total: Int64, _ used: Int64) -> Void)) {
+        fatalError("HTTPFileProvider is an abstract class. Please implement \(#function) in subclass.")
+    }
+    
+    open func searchFiles(path: String, recursive: Bool, query: NSPredicate, foundItemHandler: ((FileObject) -> Void)?, completionHandler: @escaping ((_ files: [FileObject], _ error: Error?) -> Void)) -> Progress? {
+        fatalError("HTTPFileProvider is an abstract class. Please implement \(#function) in subclass.")
+    }
+    
+    open func isReachable(completionHandler: @escaping (Bool) -> Void) {
+        self.storageProperties { total, _ in
+            completionHandler(total > 0)
+        }
+    }
+    
+    open weak var fileOperationDelegate: FileOperationDelegate?
+    
+    open func create(folder folderName: String, at atPath: String, completionHandler: SimpleCompletionHandler) -> Progress? {
+        let path = (atPath as NSString).appendingPathComponent(folderName) + "/"
+        return doOperation(.create(path: path), completionHandler: completionHandler)
+    }
+    
+    open func moveItem(path: String, to toPath: String, overwrite: Bool, completionHandler: SimpleCompletionHandler) -> Progress? {
+        return doOperation(.move(source: path, destination: toPath), completionHandler: completionHandler)
+    }
+    
+    open func copyItem(path: String, to toPath: String, overwrite: Bool, completionHandler: SimpleCompletionHandler) -> Progress? {
+        return doOperation(.copy(source: path, destination: toPath), completionHandler: completionHandler)
+    }
+    
+    open func removeItem(path: String, completionHandler: SimpleCompletionHandler) -> Progress? {
+        return doOperation(.remove(path: path), completionHandler: completionHandler)
+    }
+    
+    open func copyItem(localFile: URL, to toPath: String, overwrite: Bool, completionHandler: SimpleCompletionHandler) -> Progress? {
+        // check file is not a folder
+        guard (try? localFile.resourceValues(forKeys: [.fileResourceTypeKey]))?.fileResourceType ?? .unknown == .regular else {
+            dispatch_queue.async {
+                completionHandler?(self.throwError(localFile.path, code: URLError.fileIsDirectory))
+            }
+            return nil
+        }
+        
+        let operation = FileOperationType.copy(source: localFile.absoluteString, destination: toPath)
+        guard fileOperationDelegate?.fileProvider(self, shouldDoOperation: operation) ?? true == true else {
+            return nil
+        }
+        let request = self.request(for: operation, overwrite: overwrite)
+        return upload_simple(toPath, request: request, localFile: localFile, operation: operation, completionHandler: completionHandler)
+    }
+    
+    open func copyItem(path: String, toLocalURL destURL: URL, completionHandler: SimpleCompletionHandler) -> Progress? {
+        let operation = FileOperationType.copy(source: path, destination: destURL.absoluteString)
+        let request = self.request(for: operation)
+        return self.download_simple(path: path, request: request, operation: operation, completionHandler: { [weak self] (tempURL, error) in
+            if let error = error {
+                completionHandler?(error)
+                self?.delegateNotify(operation, error: error)
+                return
+            }
+            
+            guard let tempURL = tempURL else {
+                completionHandler?(error)
+                self?.delegateNotify(operation, error: error)
+                return
+            }
+            
+            do {
+                try FileManager.default.moveItem(at: tempURL, to: destURL)
+                completionHandler?(nil)
+                self?.delegateNotify(operation)
+            } catch let e {
+                completionHandler?(e)
+                self?.delegateNotify(operation, error: e)
+            }
+        })
+    }
+    
+    open func contents(path: String, offset: Int64, length: Int, completionHandler: @escaping ((_ contents: Data?, _ error: Error?) -> Void)) -> Progress? {
+        if length == 0 || offset < 0 {
+            dispatch_queue.async {
+                completionHandler(Data(), nil)
+            }
+            return nil
+        }
+        
+        let operation = FileOperationType.fetch(path: path)
+        var request = self.request(for: operation)
+        request.set(httpRangeWithOffset: offset, length: length)
+        return self.download_simple(path: path, request: request, operation: operation, completionHandler: { (tempURL, error) in
+            if let error = error {
+                completionHandler(nil, error)
+                return
+            }
+            
+            guard let tempURL = tempURL else {
+                completionHandler(nil, error)
+                return
+            }
+            
+            do {
+                let data = try Data(contentsOf: tempURL)
+                completionHandler(data, nil)
+            } catch let e {
+                completionHandler(nil, e)
+            }
+        })
+    }
+    
+    public func writeContents(path: String, contents data: Data?, atomically: Bool, overwrite: Bool, completionHandler: SimpleCompletionHandler) -> Progress? {
+        let operation = FileOperationType.modify(path: path)
+        guard fileOperationDelegate?.fileProvider(self, shouldDoOperation: operation) ?? true == true else {
+            return nil
+        }
+        let request = self.request(for: operation, overwrite: overwrite, attributes: [.contentModificationDateKey: Date()])
+        return upload_simple(path, request: request, data: data ?? Data(), operation: operation, completionHandler: completionHandler)
+    }
+    
+    internal func request(for operation: FileOperationType, overwrite: Bool = false, attributes: [URLResourceKey: Any] = [:]) -> URLRequest {
+        fatalError("HTTPFileProvider is an abstract class. Please implement \(#function) in subclass.")
+    }
+    
+    internal func serverError(with code: FileProviderHTTPErrorCode, path: String?, data: Data?) -> FileProviderHTTPError {
+        fatalError("HTTPFileProvider is an abstract class. Please implement \(#function) in subclass.")
+    }
+    
+    internal func multiStatusHandler(source: String, data: Data, completionHandler: SimpleCompletionHandler) -> Void {
+        // WebDAV will override this function
+    }
+    
+    fileprivate func doOperation(_ operation: FileOperationType, completionHandler: SimpleCompletionHandler) -> Progress? {
+        guard fileOperationDelegate?.fileProvider(self, shouldDoOperation: operation) ?? true == true else {
+            return nil
+        }
+        
+        let progress = Progress(totalUnitCount: 1)
+        progress.setUserInfoObject(operation, forKey: .fileProvderOperationTypeKey)
+        progress.kind = .file
+        progress.setUserInfoObject(Progress.FileOperationKind.downloading, forKey: .fileOperationKindKey)
+        
+        let request = self.request(for: operation)
+        
+        let task = session.dataTask(with: request, completionHandler: { (data, response, error) in
+            var serverError: FileProviderHTTPError?
+            if let response = response as? HTTPURLResponse, response.statusCode >= 300, let code = FileProviderHTTPErrorCode(rawValue: response.statusCode) {
+                serverError = self.serverError(with: code, path: operation.source, data: data)
+            }
+            
+            if let response = response as? HTTPURLResponse, FileProviderHTTPErrorCode(rawValue: response.statusCode) == .multiStatus, let data = data {
+                self.multiStatusHandler(source: operation.source, data: data, completionHandler: completionHandler)
+            }
+            
+            if serverError == nil && error == nil {
+                progress.completedUnitCount = 1
+            } else {
+                progress.cancel()
+            }
+            completionHandler?(serverError ?? error)
+            self.delegateNotify(operation, error: serverError ?? error)
+        })
+        task.taskDescription = operation.json
+        progress.cancellationHandler = { [weak task] in
+            task?.cancel()
+        }
+        progress.setUserInfoObject(Date(), forKey: .startingTimeKey)
+        task.resume()
+        return progress
+    }
+    
+    internal func upload_simple(_ targetPath: String, request: URLRequest, data: Data? = nil, localFile: URL? = nil, operation: FileOperationType, completionHandler: SimpleCompletionHandler) -> Progress? {
+        let size = data?.count ?? Int((try? localFile?.resourceValues(forKeys: [.fileSizeKey]))??.fileSize ?? -1)
+        
+        var progress = Progress(parent: nil, userInfo: nil)
+        progress.setUserInfoObject(operation, forKey: .fileProvderOperationTypeKey)
+        progress.kind = .file
+        progress.setUserInfoObject(Progress.FileOperationKind.downloading, forKey: .fileOperationKindKey)
+        progress.totalUnitCount = Int64(size)
+        
+        let task: URLSessionUploadTask
+        if let data = data {
+            task = session.uploadTask(with: request, from: data)
+        } else if let localFile = localFile {
+            task = session.uploadTask(with: request, fromFile: localFile)
+        } else {
+            return nil
+        }
+        
+        completionHandlersForTasks[session.sessionDescription!]?[task.taskIdentifier] = { [weak self] error in
+            var responseError: FileProviderHTTPError?
+            if let code = (task.response as? HTTPURLResponse)?.statusCode , code >= 300, let rCode = FileProviderHTTPErrorCode(rawValue: code) {
+                // We can't fetch server result from delegate!
+                responseError = self?.serverError(with: rCode, path: targetPath, data: nil)
+            }
+            if !(responseError == nil && error == nil) {
+                progress.cancel()
+            }
+            completionHandler?(responseError ?? error)
+            self?.delegateNotify(operation, error: responseError ?? error)
+        }
+        task.taskDescription = operation.json
+        task.addObserver(sessionDelegate!, forKeyPath: #keyPath(URLSessionTask.countOfBytesSent), options: .new, context: &progress)
+        progress.cancellationHandler = { [weak task] in
+            task?.cancel()
+        }
+        progress.setUserInfoObject(Date(), forKey: .startingTimeKey)
+        task.resume()
+        return progress
+    }
+    
+    internal func download_simple(path: String, request: URLRequest, operation: FileOperationType, completionHandler: @escaping ((_ tempURL: URL?, _ error: Error?) -> Void)) -> Progress? {
+        var progress = Progress(parent: nil, userInfo: nil)
+        progress.setUserInfoObject(operation, forKey: .fileProvderOperationTypeKey)
+        progress.kind = .file
+        progress.setUserInfoObject(Progress.FileOperationKind.downloading, forKey: .fileOperationKindKey)
+        
+        let task = session.downloadTask(with: request)
+        completionHandlersForTasks[session.sessionDescription!]?[task.taskIdentifier] = { error in
+            if error != nil {
+                progress.cancel()
+            }
+            completionHandler(nil, error)
+            self.delegateNotify(operation, error: error)
+        }
+        downloadCompletionHandlersForTasks[session.sessionDescription!]?[task.taskIdentifier] = { tempURL in
+            guard let httpResponse = task.response as? HTTPURLResponse , httpResponse.statusCode < 300 else {
+                let code = FileProviderHTTPErrorCode(rawValue: (task.response as? HTTPURLResponse)?.statusCode ?? -1)
+                let errorData : Data? = nil //Data(contentsOf:cacheURL) // TODO: Figure out how to get error response data for the error description
+                let serverError : FileProviderHTTPError? = code != nil ? self.serverError(with: code!, path: path, data: errorData) : nil
+                if serverError != nil {
+                    progress.cancel()
+                }
+                completionHandler(nil, serverError)
+                self.delegateNotify(operation)
+                return
+            }
+            
+            completionHandler(tempURL, nil)
+        }
+        task.taskDescription = operation.json
+        task.addObserver(sessionDelegate!, forKeyPath: #keyPath(URLSessionTask.countOfBytesReceived), options: .new, context: &progress)
+        task.addObserver(sessionDelegate!, forKeyPath: #keyPath(URLSessionTask.countOfBytesExpectedToReceive), options: .new, context: &progress)
+        progress.cancellationHandler = { [weak task] in
+            task?.cancel()
+        }
+        progress.setUserInfoObject(Date(), forKey: .startingTimeKey)
+        task.resume()
+        return progress
+    }
+}
+
+extension HTTPFileProvider: FileProvider { }
@@ -175,6 +175,7 @@ open class LocalFileProvider: FileProvider, FileProviderMonitor, FileProvideUndo
    
    open func searchFiles(path: String, recursive: Bool, query: NSPredicate, foundItemHandler: ((FileObject) -> Void)?, completionHandler: @escaping ((_ files: [FileObject], _ error: Error?) -> Void)) -> Progress? {
        let progress = Progress(parent: nil, userInfo: nil)
+        progress.setUserInfoObject(self.url(of: path), forKey: .fileURLKey)
        
        dispatch_queue.async {
            progress.setUserInfoObject(Date(), forKey: .startingTimeKey)
@@ -210,58 +211,73 @@ open class LocalFileProvider: FileProvider, FileProviderMonitor, FileProvideUndo
    
    @discardableResult
    open func create(folder folderName: String, at atPath: String, completionHandler: SimpleCompletionHandler) -> Progress? {
-        let opType = FileOperationType.create(path: (atPath as NSString).appendingPathComponent(folderName) + "/")
-        return self.doOperation(opType, completionHandler: completionHandler)
+        let operation = FileOperationType.create(path: (atPath as NSString).appendingPathComponent(folderName) + "/")
+        return self.doOperation(operation, completionHandler: completionHandler)
    }
    
    @discardableResult
    open func moveItem(path: String, to toPath: String, overwrite: Bool = false, completionHandler: SimpleCompletionHandler) -> Progress? {
-        let opType = FileOperationType.move(source: path, destination: toPath)
-
-        if !overwrite && self.fileManager.fileExists(atPath: self.url(of: toPath).path) {
-            completionHandler?(self.throwError(toPath, code: CocoaError.fileWriteFileExists as FoundationErrorEnum))
+        let operation = FileOperationType.move(source: path, destination: toPath)
+        
+        let fileExists = ((try? self.url(of: toPath).checkResourceIsReachable()) ?? false) ||
+            ((try? self.url(of: toPath).checkPromisedItemIsReachable()) ?? false)
+        if !overwrite && fileExists {
+            let e = self.throwError(toPath, code: CocoaError.fileWriteFileExists)
+            dispatch_queue.async {
+                completionHandler?(e)
+            }
+            self.delegateNotify(operation, error: e)
            return nil
        }
        
-        return self.doOperation(opType, completionHandler: completionHandler)
+        return self.doOperation(operation, completionHandler: completionHandler)
    }
    
    @discardableResult
    open func copyItem(path: String, to toPath: String, overwrite: Bool = false, completionHandler: SimpleCompletionHandler) -> Progress? {
-        let opType = FileOperationType.copy(source: path, destination: toPath)
+        let operation = FileOperationType.copy(source: path, destination: toPath)
        
-        if !overwrite && self.fileManager.fileExists(atPath: self.url(of: toPath).path) {
-            self.dispatch_queue.async {
-                completionHandler?(self.throwError(toPath, code: CocoaError.fileWriteFileExists as FoundationErrorEnum))
+        let fileExists = ((try? self.url(of: toPath).checkResourceIsReachable()) ?? false) ||
+            ((try? self.url(of: toPath).checkPromisedItemIsReachable()) ?? false)
+        if !overwrite && fileExists {
+            let e = self.throwError(toPath, code: CocoaError.fileWriteFileExists)
+            dispatch_queue.async {
+                completionHandler?(e)
            }
+            self.delegateNotify(operation, error: e)
            return nil
        }
        
-        return self.doOperation(opType, completionHandler: completionHandler)
+        return self.doOperation(operation, completionHandler: completionHandler)
    }
    
    @discardableResult
    open func removeItem(path: String, completionHandler: SimpleCompletionHandler) -> Progress? {
-        let opType = FileOperationType.remove(path: path)
-        return self.doOperation(opType, completionHandler: completionHandler)
+        let operation = FileOperationType.remove(path: path)
+        return self.doOperation(operation, completionHandler: completionHandler)
    }
    
    @discardableResult
    open func copyItem(localFile: URL, to toPath: String, overwrite: Bool, completionHandler: SimpleCompletionHandler) -> Progress? {
-        if !overwrite && self.fileManager.fileExists(atPath: self.url(of: toPath).path) {
-            self.dispatch_queue.async {
-                completionHandler?(self.throwError(toPath, code: CocoaError.fileWriteFileExists as FoundationErrorEnum))
+        let operation = FileOperationType.copy(source: localFile.absoluteString, destination: toPath)
+        
+        let fileExists = ((try? self.url(of: toPath).checkResourceIsReachable()) ?? false) ||
+            ((try? self.url(of: toPath).checkPromisedItemIsReachable()) ?? false)
+        if !overwrite && fileExists {
+            let e = self.throwError(toPath, code: CocoaError.fileWriteFileExists)
+            dispatch_queue.async {
+                completionHandler?(e)
            }
+            self.delegateNotify(operation, error: e)
            return nil
        }
-        let opType = FileOperationType.copy(source: localFile.absoluteString, destination: toPath)
-        return self.doOperation(opType, forUploading: true, completionHandler: completionHandler)
+        return self.doOperation(operation, forUploading: true, completionHandler: completionHandler)
    }
    
    @discardableResult
    open func copyItem(path: String, toLocalURL: URL, completionHandler: SimpleCompletionHandler) -> Progress? {
-        let opType = FileOperationType.copy(source: path, destination: toLocalURL.absoluteString)
-        return self.doOperation(opType, completionHandler: completionHandler)
+        let operation = FileOperationType.copy(source: path, destination: toLocalURL.absoluteString)
+        return self.doOperation(operation, completionHandler: completionHandler)
    }
    
    @objc dynamic func doSimpleOperation(_ box: UndoBox) {
@@ -272,9 +288,9 @@ open class LocalFileProvider: FileProvider, FileProviderMonitor, FileProvideUndo
    }
    
    @discardableResult
-    fileprivate func doOperation(_ opType: FileOperationType, data: Data? = nil, atomically: Bool = false, forUploading: Bool = false, completionHandler: SimpleCompletionHandler) -> Progress? {
+    fileprivate func doOperation(_ operation: FileOperationType, data: Data? = nil, atomically: Bool = false, forUploading: Bool = false, completionHandler: SimpleCompletionHandler) -> Progress? {
        let progress = Progress(parent: nil, userInfo: nil)
-        progress.setUserInfoObject(opType, forKey: .fileProvderOperationTypeKey)
+        progress.setUserInfoObject(operation, forKey: .fileProvderOperationTypeKey)
        progress.kind = .file
        progress.isCancellable = false
        progress.setUserInfoObject(Progress.FileOperationKind.receiving, forKey: .fileOperationKindKey)
@@ -288,9 +304,10 @@ open class LocalFileProvider: FileProvider, FileProviderMonitor, FileProvideUndo
            }
        }
        
-        guard let sourcePath = opType.source else { return nil }
-        let destPath = opType.destination
+        let sourcePath = operation.source
+        let destPath = operation.destination
        let source: URL = urlofpath(path: sourcePath)
+        progress.setUserInfoObject(source, forKey: .fileURLKey)
        
        let dest: URL?
        if let destPath = destPath {
@@ -299,11 +316,11 @@ open class LocalFileProvider: FileProvider, FileProviderMonitor, FileProvideUndo
            dest = nil
        }
        
-        if let undoManager = self.undoManager, let undoOp = self.undoOperation(for: opType) {
-            let undoBox = UndoBox(provider: self, operation: opType, undoOperation: undoOp)
+        if let undoManager = self.undoManager, let undoOp = self.undoOperation(for: operation) {
+            let undoBox = UndoBox(provider: self, operation: operation, undoOperation: undoOp)
            undoManager.beginUndoGrouping()
            undoManager.registerUndo(withTarget: self, selector: #selector(LocalFileProvider.doSimpleOperation(_:)), object: undoBox)
-            undoManager.setActionName(opType.actionDescription)
+            undoManager.setActionName(operation.actionDescription)
            undoManager.endUndoGrouping()
        }
        
@@ -312,7 +329,7 @@ open class LocalFileProvider: FileProvider, FileProviderMonitor, FileProvideUndo
        let operationHandler: (URL, URL?) -> Void = { source, dest in
            do {
                progress.setUserInfoObject(Date(), forKey: .startingTimeKey)
-                switch opType {
+                switch operation {
                case .create:
                    if sourcePath.hasSuffix("/") {
                        progress.totalUnitCount = 1
@@ -348,9 +365,7 @@ open class LocalFileProvider: FileProvider, FileProviderMonitor, FileProvideUndo
                self.dispatch_queue.async {
                    completionHandler?(nil)
                }
-                DispatchQueue.main.async {
-                    self.delegate?.fileproviderSucceed(self, operation: opType)
-                }
+                self.delegateNotify(operation)
            } catch let e {
                if successfulSecurityScopedResourceAccess {
                    source.stopAccessingSecurityScopedResource()
@@ -359,16 +374,14 @@ open class LocalFileProvider: FileProvider, FileProviderMonitor, FileProvideUndo
                self.dispatch_queue.async {
                    completionHandler?(e)
                }
-                DispatchQueue.main.async {
-                    self.delegate?.fileproviderFailed(self, operation: opType)
-                }
+                self.delegateNotify(operation, error: e)
            }
        }
        
        if isCoorinating {
            successfulSecurityScopedResourceAccess = source.startAccessingSecurityScopedResource()
            var intents = [NSFileAccessIntent]()
-            switch opType {
+            switch operation {
            case .create, .modify:
                intents.append(NSFileAccessIntent.writingIntent(with: source, options: .forReplacing))
            case .copy:
@@ -384,13 +397,11 @@ open class LocalFileProvider: FileProvider, FileProviderMonitor, FileProvideUndo
            default:
                return nil
            }
-            self.coordinated(intents: intents, completionHandler: operationHandler, errorHandler: { error in
+            self.coordinated(intents: intents, operationHandler: operationHandler, errorHandler: { error in
                self.dispatch_queue.async {
                    completionHandler?(error)
                }
-                DispatchQueue.main.async {
-                    self.delegate?.fileproviderFailed(self, operation: opType)
-                }
+                self.delegateNotify(operation, error: error)
            })
        } else {
            operation_queue.addOperation {
@@ -402,14 +413,15 @@ open class LocalFileProvider: FileProvider, FileProviderMonitor, FileProvideUndo
    
    @discardableResult
    open func contents(path: String, completionHandler: @escaping ((_ contents: Data?, _ error: Error?) -> Void)) -> Progress? {
-        let opType = FileOperationType.fetch(path: path)
+        let operation = FileOperationType.fetch(path: path)
+        let url = self.url(of: path)
+        
        let progress = Progress(parent: nil, userInfo: nil)
-        progress.setUserInfoObject(opType, forKey: .fileProvderOperationTypeKey)
+        progress.setUserInfoObject(operation, forKey: .fileProvderOperationTypeKey)
        progress.kind = .file
        progress.isCancellable = false
        progress.setUserInfoObject(Progress.FileOperationKind.receiving, forKey: .fileOperationKindKey)
-        
-        let url = self.url(of: path)
+        progress.setUserInfoObject(url, forKey: .fileURLKey)
        progress.totalUnitCount = url.fileSize
        
        let operationHandler: (URL) -> Void = { url in
@@ -420,23 +432,23 @@ open class LocalFileProvider: FileProvider, FileProviderMonitor, FileProvideUndo
                self.dispatch_queue.async {
                    completionHandler(data, nil)
                }
+                self.delegateNotify(operation)
            } catch let e {
                progress.cancel()
                self.dispatch_queue.async {
                    completionHandler(nil, e)
                }
+                self.delegateNotify(operation, error: e)
            }
        }
        
        if isCoorinating {
            let intent = NSFileAccessIntent.readingIntent(with: url, options: .withoutChanges)
-            coordinated(intents: [intent], completionHandler: operationHandler, errorHandler: { error in
+            coordinated(intents: [intent], operationHandler: operationHandler, errorHandler: { error in
                self.dispatch_queue.async {
                    completionHandler(nil, error)
                }
-                DispatchQueue.main.async {
-                    self.delegate?.fileproviderFailed(self, operation: opType)
-                }
+                self.delegateNotify(operation, error: error)
            })
        } else {
            dispatch_queue.async {
@@ -460,19 +472,22 @@ open class LocalFileProvider: FileProvider, FileProviderMonitor, FileProvideUndo
            return self.contents(path: path, completionHandler: completionHandler)
        }

-        let opType = FileOperationType.fetch(path: path)
+        let operation = FileOperationType.fetch(path: path)
+        let url = self.url(of: path)
+        
        let progress = Progress(parent: nil, userInfo: nil)
-        progress.setUserInfoObject(opType, forKey: .fileProvderOperationTypeKey)
+        progress.setUserInfoObject(operation, forKey: .fileProvderOperationTypeKey)
        progress.kind = .file
        progress.isCancellable = false
+        progress.setUserInfoObject(url, forKey: .fileURLKey)
        progress.setUserInfoObject(Progress.FileOperationKind.receiving, forKey: .fileOperationKindKey)
        
-        let url = self.url(of: path)
-        
        let operationHandler: (URL) -> Void = { url in
            guard let handle = FileHandle(forReadingAtPath: url.path) else {
                self.dispatch_queue.async {
-                    completionHandler(nil, self.throwError(path, code: CocoaError.fileNoSuchFile as FoundationErrorEnum))
+                    let e = self.throwError(path, code: CocoaError.fileNoSuchFile)
+                    completionHandler(nil, e)
+                    self.delegateNotify(operation, error: e)
                }
                return
            }
@@ -486,7 +501,9 @@ open class LocalFileProvider: FileProvider, FileProviderMonitor, FileProvideUndo
            guard size > offset else {
                progress.cancel()
                self.dispatch_queue.async {
-                    completionHandler(nil, self.throwError(path, code: CocoaError.fileReadTooLarge as FoundationErrorEnum))
+                    let e = self.throwError(path, code: CocoaError.fileReadTooLarge)
+                    completionHandler(nil, e)
+                    self.delegateNotify(operation, error: e)
                }
                return
            }
@@ -495,7 +512,9 @@ open class LocalFileProvider: FileProvider, FileProviderMonitor, FileProvideUndo
            guard Int64(handle.offsetInFile) == offset else {
                progress.cancel()
                self.dispatch_queue.async {
-                    completionHandler(nil, self.throwError(path, code: CocoaError.fileReadTooLarge as FoundationErrorEnum))
+                    let e = self.throwError(path, code: CocoaError.fileReadTooLarge)
+                    completionHandler(nil, e)
+                    self.delegateNotify(operation, error: e)
                }
                return
            }
@@ -504,16 +523,15 @@ open class LocalFileProvider: FileProvider, FileProviderMonitor, FileProvideUndo
            progress.completedUnitCount = progress.totalUnitCount
            self.dispatch_queue.async {
                completionHandler(data, nil)
+                self.delegateNotify(operation)
            }
        }
        
        if isCoorinating {
            let intent = NSFileAccessIntent.readingIntent(with: url, options: .withoutChanges)
-            coordinated(intents: [intent], completionHandler: operationHandler, errorHandler: { error in
+            coordinated(intents: [intent], operationHandler: operationHandler, errorHandler: { error in
                completionHandler(nil, error)
-                DispatchQueue.main.async {
-                    self.delegate?.fileproviderFailed(self, operation: opType)
-                }
+                self.delegateNotify(operation, error: error)
            })
        } else {
            dispatch_queue.async {
@@ -526,9 +544,19 @@ open class LocalFileProvider: FileProvider, FileProviderMonitor, FileProvideUndo
    
    @discardableResult
    open func writeContents(path: String, contents data: Data?, atomically: Bool, overwrite: Bool, completionHandler: SimpleCompletionHandler) -> Progress? {
-        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)
+        let fileExists = ((try? self.url(of: path).checkResourceIsReachable()) ?? false) ||
+            ((try? self.url(of: path).checkPromisedItemIsReachable()) ?? false)
+        if !overwrite && fileExists {
+            let e = self.throwError(path, code: CocoaError.fileWriteFileExists)
+            dispatch_queue.async {
+                completionHandler?(e)
+            }
+            self.delegateNotify(.modify(path: path), error: e)
+            return nil
+        }
+        
+        let operation: FileOperationType = fileExists ? .modify(path: path) : .create(path: path)
+        return self.doOperation(operation, data: data ?? Data(), atomically: atomically, completionHandler: completionHandler)
    }
    
    fileprivate var monitors = [LocalFolderMonitor]()
@@ -561,9 +589,7 @@ 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: "/")))
    }
-}
-
-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 destination path, making it possible
@@ -575,19 +601,16 @@ public extension LocalFileProvider {
       - 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) {
+    open func create(symbolicLink path: String, withDestinationPath destPath: String, completionHandler: SimpleCompletionHandler) {
        operation_queue.addOperation {
+            let operation = FileOperationType.link(link: path, target: destPath)
            do {
                try self.opFileManager.createSymbolicLink(at: self.url(of: path), withDestinationURL: self.url(of: destPath))
                completionHandler?(nil)
-                DispatchQueue.main.async {
-                    self.delegate?.fileproviderSucceed(self, operation: .link(link: path, target: destPath))
-                }
+                self.delegateNotify(operation)
            } catch let e {
                completionHandler?(e)
-                DispatchQueue.main.async {
-                    self.delegate?.fileproviderFailed(self, operation: .link(link: path, target: destPath))
-                }
+                self.delegateNotify(operation, error: e)
            }
        }
    }
@@ -597,7 +620,7 @@ public extension LocalFileProvider {
    /// - Parameters:
    ///   - path: The path of a file or directory.
    ///   - completionHandler: Returns destination url of given symbolic link, or an `Error` object if it fails.
-    public func destination(ofSymbolicLink path: String, completionHandler: @escaping (_ url: URL?, _ error: Error?) -> Void) {
+    open func destination(ofSymbolicLink path: String, completionHandler: @escaping (_ url: URL?, _ error: Error?) -> Void) {
        dispatch_queue.async {
            do {
                let destPath = try self.opFileManager.destinationOfSymbolicLink(atPath: self.url(of: path).path)
@@ -611,18 +634,18 @@ public extension LocalFileProvider {
 }

 internal extension LocalFileProvider {
-    func coordinated(intents: [NSFileAccessIntent], completionHandler: @escaping (_ url: URL) -> Void, errorHandler: ((_ error: Error) -> Void)? = nil) {
+    func coordinated(intents: [NSFileAccessIntent], operationHandler: @escaping (_ url: URL) -> Void, errorHandler: ((_ error: Error) -> Void)? = nil) {
        let coordinator = NSFileCoordinator(filePresenter: nil)
        coordinator.coordinate(with: intents, queue: operation_queue) { (error) in
            if let error = error {
                errorHandler?(error)
                return
            }
-            completionHandler(intents.first!.url)
+            operationHandler(intents.first!.url)
        }
    }
    
-    func coordinated(intents: [NSFileAccessIntent], moving: Bool = false, completionHandler: @escaping (_ sourceUrl: URL, _ destURL: URL?) -> Void, errorHandler:  ((_ error: Error) -> Void)? = nil) {
+    func coordinated(intents: [NSFileAccessIntent], moving: Bool = false, operationHandler: @escaping (_ sourceUrl: URL, _ destURL: URL?) -> Void, errorHandler:  ((_ error: Error) -> Void)? = nil) {
        let coordinator = NSFileCoordinator(filePresenter: nil)
        coordinator.coordinate(with: intents, queue: operation_queue) { (error) in
            if let error = error {
@@ -634,7 +657,7 @@ internal extension LocalFileProvider {
            if moving, let newDest = newDest {
                coordinator.item(at: newSource, willMoveTo: newDest)
            }
-            completionHandler(newSource, newDest)
+            operationHandler(newSource, newDest)
            if moving, let newDest = newDest {
                coordinator.item(at: newSource, didMoveTo: newDest)
            }
@@ -17,59 +17,10 @@ import CoreGraphics
 
 - Note: Uploading files and data are limited to 100MB, for now.
 */
-open class OneDriveFileProvider: FileProviderBasicRemote {
-    open class var type: String { return "OneDrive" }
-    open let baseURL: URL?
+open class OneDriveFileProvider: HTTPFileProvider, FileProviderSharing {
+    override open class var type: String { return "OneDrive" }
    /// Drive name for user, default is `root`. Changing its value will effect on new operations.
    open var drive: String
-    /// Generated storage url from server url and drive name
-    open var currentPath: String
-    
-    open var dispatch_queue: DispatchQueue
-    open var operation_queue: OperationQueue {
-        willSet {
-            assert(_session == nil, "It's not effective to change dispatch_queue property after session is initialized.")
-        }
-    }
-    
-    open weak var delegate: FileProviderDelegate?
-    open var credential: URLCredential? {
-        didSet {
-            sessionDelegate?.credential = self.credential
-        }
-    }
-    open private(set) var cache: URLCache?
-    public var useCache: Bool
-    public var validatingCache: Bool
-   
-    fileprivate var _session: URLSession?
-    internal fileprivate(set) var sessionDelegate: SessionDelegate?
-    public var session: URLSession {
-        get {
-            if _session == nil {
-                self.sessionDelegate = SessionDelegate(fileProvider: self)
-                let 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!)
-        }
-    }
    
    /**
     Initializer for Onedrive provider with given client ID and Token.
@@ -87,22 +38,9 @@ open class OneDriveFileProvider: FileProviderBasicRemote {
     */
    public init(credential: URLCredential?, serverURL: URL? = nil, drive: String = "root", cache: URLCache? = nil) {
        let baseURL = serverURL?.absoluteURL ?? URL(string: "https://api.onedrive.com/")!
-        self.baseURL = baseURL.absoluteString.hasSuffix("/") ? baseURL : baseURL.appendingPathComponent("")
+        let refinedBaseURL = baseURL.absoluteString.hasSuffix("/") ? baseURL : baseURL.appendingPathComponent("")
        self.drive = drive
-        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"
+        super.init(baseURL: refinedBaseURL, credential: credential, cache: cache)
    }
    
    public required convenience init?(coder aDecoder: NSCoder) {
@@ -114,20 +52,12 @@ open class OneDriveFileProvider: FileProviderBasicRemote {
        self.validatingCache = aDecoder.decodeBool(forKey: "validatingCache")
    }
    
-    open func encode(with aCoder: NSCoder) {
-        aCoder.encode(self.credential, forKey: "credential")
-        aCoder.encode(self.baseURL, forKey: "baseURL")
+    open override func encode(with aCoder: NSCoder) {
+        super.encode(with: aCoder)
        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 {
+    open override func copy(with zone: NSZone? = nil) -> Any {
        let copy = OneDriveFileProvider(credential: self.credential, serverURL: self.baseURL, drive: self.drive, cache: self.cache)
        copy.currentPath = self.currentPath
        copy.delegate = self.delegate
@@ -137,25 +67,13 @@ open class OneDriveFileProvider: FileProviderBasicRemote {
        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)) {
+    open override func contentsOfDirectory(path: String, completionHandler: @escaping ((_ contents: [FileObject], _ error: Error?) -> Void)) {
        list(path) { (contents, cursor, error) in
            completionHandler(contents, error)
        }
    }
    
-    open func attributesOfItem(path: String, completionHandler: @escaping ((_ attributes: FileObject?, _ error: Error?) -> Void)) {
+    open override func attributesOfItem(path: String, completionHandler: @escaping ((_ attributes: FileObject?, _ error: Error?) -> Void)) {
        var request = URLRequest(url: url(of: path))
        request.httpMethod = "GET"
        request.set(httpAuthentication: credential, with: .oAuth2)
@@ -174,8 +92,8 @@ open class OneDriveFileProvider: FileProviderBasicRemote {
        task.resume()
    }
    
-    open func storageProperties(completionHandler: @escaping ((_ total: Int64, _ used: Int64) -> Void)) {
-        var request = URLRequest(url: url())
+    open override func storageProperties(completionHandler: @escaping ((_ total: Int64, _ used: Int64) -> Void)) {
+        var request = URLRequest(url: url(of: ""))
        request.httpMethod = "GET"
        request.set(httpAuthentication: credential, with: .oAuth2)
        let task = session.dataTask(with: request, completionHandler: { (data, response, error) in
@@ -190,13 +108,14 @@ open class OneDriveFileProvider: FileProviderBasicRemote {
        task.resume()
    }
    
-    open func searchFiles(path: String, recursive: Bool, query: NSPredicate, foundItemHandler: ((FileObject) -> Void)?, completionHandler: @escaping ((_ files: [FileObject], _ error: Error?) -> Void)) -> Progress? {
+    open override func searchFiles(path: String, recursive: Bool, query: NSPredicate, foundItemHandler: ((FileObject) -> Void)?, completionHandler: @escaping ((_ files: [FileObject], _ error: Error?) -> Void)) -> Progress? {
        var foundFiles = [OneDriveFileObject]()
        var queryStr: String?
        queryStr = query.findValue(forKey: "name") as? String ?? query.findAllValues(forKey: nil).flatMap { $0.value as? String }.first
        guard let finalQueryStr = queryStr else { return nil }
        let progress = Progress(parent: nil, userInfo: nil)
-        search(path, query: finalQueryStr, progress: progress, foundItem: { (file) in
+        progress.setUserInfoObject(url(of: path), forKey: .fileURLKey)
+        search(path, query: finalQueryStr, recursive: recursive, progress: progress, foundItem: { (file) in
            if query.evaluate(with: file.mapPredicate()) {
                foundFiles.append(file)
                foundItemHandler?(file)
@@ -207,13 +126,8 @@ open class OneDriveFileProvider: FileProviderBasicRemote {
        return progress
    }
    
-    open func url(of path: String? = nil, modifier: String? = nil) -> URL {
-        var rpath: String
-        if let path = path {
-            rpath = path
-        } else {
-            rpath = self.currentPath
-        }
+    open func url(of path: String, modifier: String? = nil) -> URL {
+        var rpath: String = path
        
        let driveURL = baseURL!.appendingPathComponent("drive/\(drive):/")
        
@@ -235,8 +149,8 @@ open class OneDriveFileProvider: FileProviderBasicRemote {
        return  driveURL.appendingPathComponent(rpath)
    }
    
-    open func isReachable(completionHandler: @escaping (Bool) -> Void) {
-        var request = URLRequest(url: url())
+    open override func isReachable(completionHandler: @escaping (Bool) -> Void) {
+        var request = URLRequest(url: url(of: ""))
        request.httpMethod = "HEAD"
        request.set(httpAuthentication: credential, with: .oAuth2)
        let task = session.dataTask(with: request, completionHandler: { (data, response, error) in
@@ -246,215 +160,75 @@ open class OneDriveFileProvider: FileProviderBasicRemote {
        task.resume()
    }
    
-    open weak var fileOperationDelegate: FileOperationDelegate?
-}
-
-extension OneDriveFileProvider: FileProviderOperations {
-    
-    open func create(folder folderName: String, at atPath: String, completionHandler: SimpleCompletionHandler) -> Progress? {
-        let path = (atPath as NSString).appendingPathComponent(folderName) + "/"
-        return doOperation(.create(path: path), completionHandler: completionHandler)
-    }
-    
-    open func moveItem(path: String, to toPath: String, overwrite: Bool, completionHandler: SimpleCompletionHandler) -> Progress? {
-        return doOperation(.move(source: path, destination: toPath), completionHandler: completionHandler)
-    }
-    
-    open func copyItem(path: String, to toPath: String, overwrite: Bool, completionHandler: SimpleCompletionHandler) -> Progress? {
-        return doOperation(.copy(source: path, destination: toPath), completionHandler: completionHandler)
-    }
-    
-    open func removeItem(path: String, completionHandler: SimpleCompletionHandler) -> Progress? {
-        return doOperation(.remove(path: path), completionHandler: completionHandler)
-    }
-    
-    fileprivate func doOperation(_ operation: FileOperationType, completionHandler: SimpleCompletionHandler) -> Progress? {
-        guard fileOperationDelegate?.fileProvider(self, shouldDoOperation: operation) ?? true == true else {
-            return nil
-        }
-        
-        let progress = Progress(totalUnitCount: 1)
-        progress.setUserInfoObject(operation, forKey: .fileProvderOperationTypeKey)
-        progress.kind = .file
-        progress.setUserInfoObject(Progress.FileOperationKind.downloading, forKey: .fileOperationKindKey)
-        
-        guard let sourcePath = operation.source else { return nil }
-        let destPath = operation.destination
-        var request = URLRequest(url: url(of: sourcePath))
+    override func request(for operation: FileOperationType, overwrite: Bool = false, attributes: [URLResourceKey : Any] = [:]) -> URLRequest {
+        let method: String
+        let url: URL
        switch operation {
-        case .create:
-            request.httpMethod = "CREATE"
-        case .copy:
-            request.httpMethod = "POST"
-        case .move:
-            request.httpMethod = "PATCH"
-        case .remove:
-            request.httpMethod = "DELETE"
-        default: // modify, link, fetch
-            return nil
+        case .fetch(path: let path):
+            method = "GET"
+            url = self.url(of: path, modifier: "content")
+        case .modify(path: let path):
+            method = "PUT"
+            let queryStr = overwrite ? "" : "?@name.conflictBehavior=fail"
+            url = self.url(of: path, modifier: "content\(queryStr)")
+        case .create(path: let path):
+            method = "CREATE"
+            url = self.url(of: path)
+        case .copy(let source, let dest) where !source.hasPrefix("file://") && !dest.hasPrefix("file://"):
+            method = "POST"
+            url = self.url(of: source)
+        case .copy(let source, let dest) where source.hasPrefix("file://"):
+            method = "PUT"
+            let queryStr = overwrite ? "" : "?@name.conflictBehavior=fail"
+            url = self.url(of: dest, modifier: "content\(queryStr)")
+        case .copy(let source, let dest) where dest.hasPrefix("file://"):
+            method = "GET"
+            url = self.url(of: source, modifier: "content")
+        case .move(source: let source, destination: _):
+            method = "PATCH"
+            url = self.url(of: source)
+        case .remove(path: let path):
+            method = "DELETE"
+            url = self.url(of: path)
+        default: // link
+            fatalError("Unimplemented operation \(operation.description) in \(#file)")
        }
-        
+        var request = URLRequest(url: url)
+        request.httpMethod = method
        request.set(httpAuthentication: credential, with: .oAuth2)
-        var requestDictionary = [String: AnyObject]()
-        if let dest = correctPath(destPath) as NSString? {
-            request.set(contentType: .json)
-            requestDictionary["parentReference"] = ("/drive/\(drive):" + dest.deletingLastPathComponent) as NSString
-            requestDictionary["name"] = dest.lastPathComponent as NSString
+        
+        switch operation {
+        case .copy(let source, let dest) where !source.hasPrefix("file://") && !dest.hasPrefix("file://"),
+             .move(source: let source, destination: let dest):
+            request.set(httpContentType: .json)
+            let cdest = (correctPath(dest) as NSString?)!
+            var requestDictionary = [String: AnyObject]()
+            requestDictionary["parentReference"] = ("/drive/\(drive):" + cdest.deletingLastPathComponent) as NSString
+            requestDictionary["name"] = cdest.lastPathComponent as NSString
            request.httpBody = Data(jsonDictionary: requestDictionary)
+        default:
+            break
        }
-        let task = session.dataTask(with: request, completionHandler: { (data, response, error) in
-            var serverError: FileProviderOneDriveError?
-            if let response = response as? HTTPURLResponse, response.statusCode >= 300, let code = FileProviderHTTPErrorCode(rawValue: response.statusCode) {
-                 serverError = FileProviderOneDriveError(code: code, path: sourcePath, errorDescription: String(data: data ?? Data(), encoding: .utf8))
-            }
-            if serverError == nil && error == nil {
-                progress.completedUnitCount = 1
-            } else {
-                progress.cancel()
-            }
-            completionHandler?(serverError ?? error)
-            self.delegateNotify(operation, error: serverError ?? error)
-        })
-        task.taskDescription = operation.json
-        progress.cancellationHandler = { [weak task] in
-            task?.cancel()
-        }
-        progress.setUserInfoObject(Date(), forKey: .startingTimeKey)
-        task.resume()
-        return progress
+        
+        return request
    }
    
-    open func copyItem(localFile: URL, to toPath: String, overwrite: Bool, completionHandler: SimpleCompletionHandler) -> Progress? {
-        // check file is not a folder
-        guard (try? localFile.resourceValues(forKeys: [.fileResourceTypeKey]))?.fileResourceType ?? .unknown == .regular else {
-            dispatch_queue.async {
-                completionHandler?(self.throwError(localFile.path, code: URLError.fileIsDirectory))
-            }
-            return nil
-        }
-        
-        let opType = FileOperationType.copy(source: localFile.absoluteString, destination: toPath)
-        guard fileOperationDelegate?.fileProvider(self, shouldDoOperation: opType) ?? true == true else {
-            return nil
-        }
-        return upload_simple(toPath, localFile: localFile, overwrite: overwrite, operation: opType, completionHandler: completionHandler)
+    override func serverError(with code: FileProviderHTTPErrorCode, path: String?, data: Data?) -> FileProviderHTTPError {
+        return FileProviderOneDriveError(code: code, path: path ?? "", errorDescription:  data.flatMap({ String(data: $0, encoding: .utf8) }))
    }
    
-    open func copyItem(path: String, toLocalURL destURL: URL, completionHandler: SimpleCompletionHandler) -> Progress? {
-        let opType = FileOperationType.copy(source: path, destination: destURL.absoluteString)
-        guard fileOperationDelegate?.fileProvider(self, shouldDoOperation: opType) ?? true == true else {
-            return nil
-        }
-        
-        var progress = Progress(parent: nil, userInfo: nil)
-        progress.setUserInfoObject(opType, forKey: .fileProvderOperationTypeKey)
-        progress.kind = .file
-        progress.setUserInfoObject(Progress.FileOperationKind.downloading, forKey: .fileOperationKindKey)
-        
-        var request = URLRequest(url: self.url(of: path, modifier: "content"))
-        request.set(httpAuthentication: credential, with: .oAuth2)
-        let task = session.downloadTask(with: request)
-        completionHandlersForTasks[session.sessionDescription!]?[task.taskIdentifier] = { error in
-            if error != nil {
-                progress.cancel()
-            }
+    override func upload_simple(_ targetPath: String, request: URLRequest, data: Data?, localFile: URL?, operation: FileOperationType, completionHandler: SimpleCompletionHandler) -> Progress? {
+        let size = data?.count ?? Int((try? localFile?.resourceValues(forKeys: [.fileSizeKey]))??.fileSize ?? -1)
+        if size > 100 * 1024 * 1024 {
+            let error = FileProviderOneDriveError(code: .payloadTooLarge, path: targetPath, errorDescription: nil)
            completionHandler?(error)
+            self.delegateNotify(operation, error: error)
+            return nil
        }
-        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
-                if serverError != nil {
-                    progress.cancel()
-                }
-                completionHandler?(serverError)
-                return
-            }
-            do {
-                try FileManager.default.moveItem(at: tempURL, to: destURL)
-                completionHandler?(nil)
-            } catch let e {
-                completionHandler?(e)
-            }
-        }
-        task.taskDescription = opType.json
-        task.addObserver(sessionDelegate!, forKeyPath: #keyPath(URLSessionTask.countOfBytesReceived), options: .new, context: &progress)
-        task.addObserver(sessionDelegate!, forKeyPath: #keyPath(URLSessionTask.countOfBytesExpectedToReceive), options: .new, context: &progress)
-        progress.cancellationHandler = { [weak task] in
-            task?.cancel()
-        }
-        progress.setUserInfoObject(Date(), forKey: .startingTimeKey)
-        task.resume()
-        return progress
+        
+        return super.upload_simple(targetPath, request: request, data: data, localFile: localFile, operation: operation, completionHandler: completionHandler)
    }
-}

-extension OneDriveFileProvider: FileProviderReadWrite {
-    open func contents(path: String, offset: Int64, length: Int, completionHandler: @escaping ((_ contents: Data?, _ error: Error?) -> Void)) -> Progress? {
-        if length == 0 || offset < 0 {
-            dispatch_queue.async {
-                completionHandler(Data(), nil)
-            }
-            return nil
-        }
-        
-        let opType = FileOperationType.fetch(path: path)
-        
-        var progress = Progress(parent: nil, userInfo: nil)
-        progress.setUserInfoObject(opType, forKey: .fileProvderOperationTypeKey)
-        progress.kind = .file
-        progress.setUserInfoObject(Progress.FileOperationKind.downloading, forKey: .fileOperationKindKey)
-        
-        var request = URLRequest(url: self.url(of: path, modifier: "content"))
-        request.httpMethod = "GET"
-        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
-            if error != nil {
-                progress.cancel()
-            }
-            completionHandler(nil, error)
-        }
-        downloadCompletionHandlersForTasks[session.sessionDescription!]?[task.taskIdentifier] = { tempURL in            
-            guard let httpResponse = task.response as? HTTPURLResponse , httpResponse.statusCode < 300 else {
-                let code = FileProviderHTTPErrorCode(rawValue: (task.response as? HTTPURLResponse)?.statusCode ?? -1)
-                let errorData : Data? = nil //Data(contentsOf: cacheURL) // TODO: Figure out how to get error response data for the error description
-                let serverError : FileProviderOneDriveError? = code != nil ? FileProviderOneDriveError(code: code!, path: path, errorDescription: String(data: errorData ?? Data(), encoding: .utf8)) : nil
-                if serverError != nil {
-                    progress.cancel()
-                }
-                completionHandler(nil, serverError)
-                return
-            }
-            do {
-                let data = try Data(contentsOf: tempURL)
-                completionHandler(data, nil)
-            } catch let e {
-                completionHandler(nil, e)
-            }
-        }
-        task.taskDescription = opType.json
-        task.addObserver(sessionDelegate!, forKeyPath: #keyPath(URLSessionTask.countOfBytesReceived), options: .new, context: &progress)
-        task.addObserver(sessionDelegate!, forKeyPath: #keyPath(URLSessionTask.countOfBytesExpectedToReceive), options: .new, context: &progress)
-        progress.cancellationHandler = { [weak task] in
-            task?.cancel()
-        }
-        progress.setUserInfoObject(Date(), forKey: .startingTimeKey)
-        task.resume()
-        return progress
-    }
-    
-    open func writeContents(path: String, contents data: Data?, atomically: Bool, overwrite: Bool, completionHandler: SimpleCompletionHandler) -> Progress? {
-        let opType = FileOperationType.modify(path: path)
-        guard fileOperationDelegate?.fileProvider(self, shouldDoOperation: opType) ?? true == true else {
-            return nil
-        }
-        // FIXME: remove 150MB restriction
-        return upload_simple(path, data: data ?? Data(), overwrite: overwrite, operation: opType, completionHandler: completionHandler)
-    }
-    
    fileprivate func registerNotifcation(path: String, eventHandler: (() -> Void)) {
        /* There is two ways to monitor folders changing in OneDrive. Either using webooks
         * which means you have to implement a server to translate it to push notifications
@@ -467,9 +241,7 @@ extension OneDriveFileProvider: FileProviderReadWrite {
    fileprivate func unregisterNotifcation(path: String) {
        NotImplemented()
    }
-}
-
-extension OneDriveFileProvider: FileProviderSharing {
+    
    open func publicLink(to path: String, completionHandler: @escaping ((_ link: URL?, _ attribute: FileObject?, _ expiration: Date?, _ error: Error?) -> Void)) {
        var request = URLRequest(url: self.url(of: path, modifier: "action.createLink"))
        request.httpMethod = "POST"
@@ -559,5 +331,3 @@ extension OneDriveFileProvider: ExtendedFileProvider {
        task.resume()
    }
 }
-
-extension OneDriveFileProvider: FileProvider { }
@@ -114,66 +114,15 @@ internal extension OneDriveFileProvider {
        task.resume()
    }
    
-    func upload_simple(_ targetPath: String, data: Data? = nil, localFile: URL? = nil, modifiedDate: Date = Date(), overwrite: Bool, operation: FileOperationType, completionHandler: SimpleCompletionHandler) -> Progress? {
-        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)
-            self.delegateNotify(.create(path: targetPath), error: error)
-            return nil
-        }
-        
-        var progress = Progress(parent: nil, userInfo: nil)
-        progress.setUserInfoObject(operation, forKey: .fileProvderOperationTypeKey)
-        progress.kind = .file
-        progress.setUserInfoObject(Progress.FileOperationKind.downloading, forKey: .fileOperationKindKey)
-        progress.totalUnitCount = Int64(size)
-        
-        let queryStr = overwrite ? "" : "?@name.conflictBehavior=fail"
-        let url = self.url(of: targetPath, modifier: "content\(queryStr)")
-        var request = URLRequest(url: url)
-        request.httpMethod = "PUT"
-        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 = (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)
-            }
-            if !(responseError == nil && error == nil) {
-                progress.cancel()
-            }
-            completionHandler?(responseError ?? error)
-            self?.delegateNotify(.create(path: targetPath), error: responseError ?? error)
-        }
-        task.taskDescription = operation.json
-        task.addObserver(sessionDelegate!, forKeyPath: #keyPath(URLSessionTask.countOfBytesSent), options: .new, context: &progress)
-        progress.cancellationHandler = { [weak task] in
-            task?.cancel()
-        }
-        progress.setUserInfoObject(Date(), forKey: .startingTimeKey)
-        task.resume()
-        return progress
-    }
-    
-    func search(_ startPath: String = "", query: String, next: URL? = nil, progress: Progress, foundItem: @escaping ((_ file: OneDriveFileObject) -> Void), completionHandler: @escaping ((_ error: Error?) -> Void)) {
+    func search(_ startPath: String = "", query: String, recursive: Bool, next: URL? = nil, progress: Progress, foundItem: @escaping ((_ file: OneDriveFileObject) -> Void), completionHandler: @escaping ((_ error: Error?) -> Void)) {
        if progress.isCancelled {
            return
        }
        
        let url: URL
        let q = query.addingPercentEncoding(withAllowedCharacters: .urlQueryAllowed)!
-        url = next ?? self.url(of: startPath, modifier: "view.search?q=\(q)")
+        let expanded = recursive ? "&expand=children" : ""
+        url = next ?? self.url(of: startPath, modifier: "view.search?q=\(q)\(expanded)")
        var request = URLRequest(url: url)
        request.httpMethod = "GET"
        request.set(httpAuthentication: credential, with: .oAuth2)
@@ -192,7 +141,7 @@ internal extension OneDriveFileProvider {
                    }
                    let next: URL? = (json["@odata.nextLink"] as? String).flatMap { URL(string: $0) }
                    if !progress.isCancelled, let next = next {
-                        self.search(startPath, query: query, next: next, progress: progress, foundItem: foundItem, completionHandler: completionHandler)
+                        self.search(startPath, query: query, recursive: recursive, next: next, progress: progress, foundItem: foundItem, completionHandler: completionHandler)
                    } else {
                        completionHandler(responseError ?? error)
                    }
@@ -282,14 +231,4 @@ internal extension OneDriveFileProvider {
        
        return (dic, keys)
    }
-    
-    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)
-            }
-        })
-    }
 }
@@ -31,18 +31,6 @@ extension FileProviderHTTPError {
    }
 }

-/// 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]]()
@@ -109,19 +97,21 @@ final public class SessionDelegate: NSObject, URLSessionDataDelegate, URLSession
            case #keyPath(URLSessionTask.countOfBytesExpectedToReceive), #keyPath(URLSessionTask.countOfBytesExpectedToSend):
                progress.totalUnitCount = newVal
            default:
-                break
+                super.observeValue(forKeyPath: keyPath, of: object, change: change, context: context)
            }
        }
-        super.observeValue(forKeyPath: keyPath, of: object, change: change, context: context)
    }
    
    // codebeat:disable[ARITY]
    public func urlSession(_ session: URLSession, task: URLSessionTask, didCompleteWithError error: Error?) {
-        task.removeObserver(self, forKeyPath: #keyPath(URLSessionTask.countOfBytesReceived))
-        task.removeObserver(self, forKeyPath: #keyPath(URLSessionTask.countOfBytesExpectedToReceive))
-        task.removeObserver(self, forKeyPath: #keyPath(URLSessionTask.countOfBytesSent))
-        task.removeObserver(self, forKeyPath: #keyPath(URLSessionTask.countOfBytesReceived))
-        
+        if task is URLSessionDownloadTask {
+            task.removeObserver(self, forKeyPath: #keyPath(URLSessionTask.countOfBytesReceived))
+            task.removeObserver(self, forKeyPath: #keyPath(URLSessionTask.countOfBytesExpectedToReceive))
+        }
+        if task is URLSessionUploadTask {
+            task.removeObserver(self, forKeyPath: #keyPath(URLSessionTask.countOfBytesSent))
+            //task.removeObserver(self, forKeyPath: #keyPath(URLSessionTask.countOfBytesExpectedToSend))
+        }
        if !(error == nil && task is URLSessionDownloadTask) {
            let completionHandler = completionHandlersForTasks[session.sessionDescription!]?[task.taskIdentifier] ?? nil
            completionHandler?(error)
@@ -143,8 +133,8 @@ final public class SessionDelegate: NSObject, URLSessionDataDelegate, URLSession
        }
        
        DispatchQueue.main.async {
-            if error != nil {
-                fileProvider.delegate?.fileproviderFailed(fileProvider, operation: op)
+            if let error = error {
+                fileProvider.delegate?.fileproviderFailed(fileProvider, operation: op, error: error)
            } else {
                fileProvider.delegate?.fileproviderSucceed(fileProvider, operation: op)
            }
@@ -177,30 +167,29 @@ final public class SessionDelegate: NSObject, URLSessionDataDelegate, URLSession
        switch op {
        case .create(path: let path):
            if path.hasSuffix("/") { return }
+            break
        case .modify:
            break
+        case .copy(source: let source, destination: _) where source.hasPrefix("file://"):
+            break
        default:
            return
        }
        
-        let progress = Float(totalBytesSent) / Float(totalBytesExpectedToSend)
-        
-        DispatchQueue.main.async {
-            fileProvider.delegate?.fileproviderProgress(fileProvider, operation: op, progress: progress)
-        }
+        fileProvider.delegateNotify(op, progress: Double(totalBytesSent) / Double(totalBytesExpectedToSend))
    }
    
    public func urlSession(_ session: URLSession, downloadTask: URLSessionDownloadTask, didWriteData bytesWritten: Int64, totalBytesWritten: Int64, totalBytesExpectedToWrite: Int64) {
        self.didReceivedData?(session, downloadTask, bytesWritten, totalBytesWritten, totalBytesExpectedToWrite)
        
+        if totalBytesExpectedToWrite == NSURLSessionTransferSizeUnknown { return }
+        
        guard let json = downloadTask.taskDescription?.deserializeJSON(),
              let op = FileOperationType(json: json), let fileProvider = fileProvider else {
            return
        }
        
-        DispatchQueue.main.async {
-            fileProvider.delegate?.fileproviderProgress(fileProvider, operation: op, progress: Float(totalBytesWritten) / Float(totalBytesExpectedToWrite))
-        }
+        fileProvider.delegateNotify(op, progress: Double(totalBytesWritten) / Double(totalBytesExpectedToWrite))
    }
    
    public func urlSession(_ session: URLSession, task: URLSessionTask, didReceive challenge: URLAuthenticationChallenge, completionHandler: @escaping (URLSession.AuthChallengeDisposition, URLCredential?) -> Void) {
@@ -20,57 +20,9 @@ import CoreGraphics
     in case of using this class with unencrypted HTTP connection.
     [Read this to know how](http://iosdevtips.co/post/121756573323/ios-9-xcode-7-http-connect-server-error).
 */
-open class WebDAVFileProvider: FileProviderBasicRemote {
-    open class var type: String { return "WebDAV" }
-    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.")
-        }
-    }
-    
-    public weak var delegate: FileProviderDelegate?
-    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
-    
-    fileprivate var _session: URLSession?
-    fileprivate var sessionDelegate: SessionDelegate?
-    public var session: URLSession {
-        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!)
-        }
-    }
+open class WebDAVFileProvider: HTTPFileProvider, FileProviderSharing {
+    override open class var type: String { return "WebDAV" }
+    public var credentialType: URLRequest.AuthenticationType = .digest
    
    /**
     Initializes WebDAV provider.
@@ -84,21 +36,8 @@ open class WebDAVFileProvider: FileProviderBasicRemote {
        if  !["http", "https"].contains(baseURL.uw_scheme.lowercased()) {
            return nil
        }
-        self.baseURL = (baseURL.absoluteString.hasSuffix("/") ? baseURL : baseURL.appendingPathComponent("")).absoluteURL
-        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"
+        let refinedBaseURL = (baseURL.absoluteString.hasSuffix("/") ? baseURL : baseURL.appendingPathComponent("")).absoluteURL
+        super.init(baseURL: refinedBaseURL, credential: credential, cache: cache)
    }
    
    public required convenience init?(coder aDecoder: NSCoder) {
@@ -112,19 +51,7 @@ open class WebDAVFileProvider: FileProviderBasicRemote {
        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 {
+    override open func copy(with zone: NSZone? = nil) -> Any {
        let copy = WebDAVFileProvider(baseURL: self.baseURL!, credential: self.credential, cache: self.cache)!
        copy.currentPath = self.currentPath
        copy.delegate = self.delegate
@@ -134,19 +61,7 @@ open class WebDAVFileProvider: FileProviderBasicRemote {
        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 (([FileObject], Error?) -> Void)) {
+    override open func contentsOfDirectory(path: String, completionHandler: @escaping (([FileObject], Error?) -> Void)) {
        self.contentsOfDirectory(path: path, including: [], completionHandler: completionHandler)
    }
    
@@ -155,23 +70,23 @@ open class WebDAVFileProvider: FileProviderBasicRemote {
     
     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 path: path to target directory. If empty, root will be iterated.
     - 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 operation = 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.set(httpAuthentication: credential, with: credentialType)
-        request.set(contentType: .xml)
+        request.set(httpContentType: .xml, charset: .utf8)
        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, operation: opType, completionHandler: { (data, response, error) in
+        runDataTask(with: request, operation: operation, 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)
@@ -190,7 +105,7 @@ open class WebDAVFileProvider: FileProviderBasicRemote {
        })
    }
    
-    open func attributesOfItem(path: String, completionHandler: @escaping ((_ attributes: FileObject?, _ error: Error?) -> Void)) {
+    override open func attributesOfItem(path: String, completionHandler: @escaping ((_ attributes: FileObject?, _ error: Error?) -> Void)) {
        self.attributesOfItem(path: path, including: [], completionHandler: completionHandler)
    }
    
@@ -199,7 +114,7 @@ open class WebDAVFileProvider: FileProviderBasicRemote {
     
     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 path: path to target directory. If empty, attributes of root will be returned.
     - 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.
@@ -209,9 +124,9 @@ open class WebDAVFileProvider: FileProviderBasicRemote {
        let url = self.url(of: path)
        var request = URLRequest(url: url)
        request.httpMethod = "PROPFIND"
-        request.setValue("1", forHTTPHeaderField: "Depth")
+        request.setValue("0", forHTTPHeaderField: "Depth")
        request.set(httpAuthentication: credential, with: credentialType)
-        request.set(contentType: .xml)
+        request.set(httpContentType: .xml, charset: .utf8)
        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
@@ -230,7 +145,7 @@ open class WebDAVFileProvider: FileProviderBasicRemote {
        })
    }
    
-    open func storageProperties(completionHandler: @escaping ((_ total: Int64, _ used: Int64) -> Void)) {
+    override open func storageProperties(completionHandler: @escaping ((_ total: Int64, _ used: Int64) -> Void)) {
        // Not all WebDAV clients implements RFC2518 which allows geting storage quota.
        // In this case you won't get error. totalSize is NSURLSessionTransferSizeUnknown
        // and used space is zero.
@@ -241,7 +156,7 @@ open class WebDAVFileProvider: FileProviderBasicRemote {
        request.httpMethod = "PROPFIND"
        request.setValue("0", forHTTPHeaderField: "Depth")
        request.set(httpAuthentication: credential, with: credentialType)
-        request.set(contentType: .xml)
+        request.set(httpContentType: .xml, charset: .utf8)
        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
@@ -258,15 +173,17 @@ open class WebDAVFileProvider: FileProviderBasicRemote {
        })
    }
    
-    open func searchFiles(path: String, recursive: Bool, query: NSPredicate, foundItemHandler: ((FileObject) -> Void)?, completionHandler: @escaping ((_ files: [FileObject], _ error: Error?) -> Void)) -> Progress? {
+    override open func searchFiles(path: String, recursive: Bool, query: NSPredicate, foundItemHandler: ((FileObject) -> Void)?, completionHandler: @escaping ((_ files: [FileObject], _ error: Error?) -> Void)) -> Progress? {
        let url = self.url(of: path)
        var request = URLRequest(url: url)
        request.httpMethod = "PROPFIND"
-        //request.setValue("1", forHTTPHeaderField: "Depth")
+        // Depth infinity is disabled on some servers. Implement workaround?!
+        request.setValue(recursive ? "infinity" : "1", forHTTPHeaderField: "Depth")
        request.set(httpAuthentication: credential, with: credentialType)
-        request.set(contentType: .xml)
+        request.set(httpContentType: .xml, charset: .utf8)
        request.httpBody = "<?xml version=\"1.0\" encoding=\"utf-8\" ?>\n<D:propfind xmlns:D=\"DAV:\">\n<D:allprop/></D:propfind>".data(using: .utf8)
        let progress = Progress(parent: nil, userInfo: nil)
+        progress.setUserInfoObject(url, forKey: .fileURLKey)
        let task = session.dataTask(with: request) { (data, response, error) in
            // FIXME: paginating results
            var responseError: FileProviderWebDavError?
@@ -299,12 +216,12 @@ open class WebDAVFileProvider: FileProviderBasicRemote {
        return progress
    }
    
-    open func isReachable(completionHandler: @escaping (Bool) -> Void) {
+    override open func isReachable(completionHandler: @escaping (Bool) -> Void) {
        var request = URLRequest(url: baseURL!)
        request.httpMethod = "PROPFIND"
        request.setValue("0", forHTTPHeaderField: "Depth")
        request.set(httpAuthentication: credential, with: credentialType)
-        request.set(contentType: .xml)
+        request.set(httpContentType: .xml, charset: .utf8)
        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
@@ -313,310 +230,101 @@ open class WebDAVFileProvider: FileProviderBasicRemote {
        })
    }
    
-    open weak var fileOperationDelegate: FileOperationDelegate?
-}
-
-extension WebDAVFileProvider: FileProviderOperations {
-    @discardableResult
-    open func create(folder folderName: String, at atPath: String, completionHandler: SimpleCompletionHandler) -> Progress? {
-        let opType = FileOperationType.create(path: (atPath as NSString).appendingPathComponent(folderName) + "/")
-        guard fileOperationDelegate?.fileProvider(self, shouldDoOperation: opType) ?? true == true else {
-            return nil
-        }
-        return self.doOperation(operation: opType, overwrite: false, completionHandler: completionHandler)
-    }
-    
-    @discardableResult
-    open func moveItem(path: String, to toPath: String, overwrite: Bool = false, completionHandler: SimpleCompletionHandler) -> Progress? {
-        let opType = FileOperationType.move(source: path, destination: toPath)
-        guard fileOperationDelegate?.fileProvider(self, shouldDoOperation: opType) ?? true == true else {
-            return nil
-        }
-        return self.doOperation(operation: opType, overwrite: overwrite, completionHandler: completionHandler)
-    }
-    
-    @discardableResult
-    open func copyItem(path: String, to toPath: String, overwrite: Bool = false, completionHandler: SimpleCompletionHandler) -> Progress? {
-        let opType = FileOperationType.copy(source: path, destination: toPath)
-        guard fileOperationDelegate?.fileProvider(self, shouldDoOperation: opType) ?? true == true else {
-            return nil
-        }
-        return self.doOperation(operation: opType, overwrite: overwrite, completionHandler: completionHandler)
-    }
-    
-    @discardableResult
-    open func removeItem(path: String, completionHandler: SimpleCompletionHandler) -> Progress? {
-        let opType = FileOperationType.remove(path: path)
-        guard fileOperationDelegate?.fileProvider(self, shouldDoOperation: opType) ?? true == true else {
-            return nil
-        }
-        return self.doOperation(operation: opType, completionHandler: completionHandler)
-    }
-    
-    fileprivate func doOperation(operation opType: FileOperationType, overwrite: Bool? = nil, completionHandler: SimpleCompletionHandler) -> Progress?  {
-        let source = opType.source!
-        let sourceURL = self.url(of: source)
-        var request = URLRequest(url: sourceURL)
-        if let dest = opType.destination {
-            request.setValue(url(of:dest).absoluteString, forHTTPHeaderField: "Destination")
-        }
-        switch opType {
-        case .create:
-            request.httpMethod = "MKCOL"
-        case .copy:
-            request.httpMethod = "COPY"
-        case .move:
-            request.httpMethod = "MOVE"
-        case .remove:
-            request.httpMethod = "DELETE"
-        default:
-            return nil
-        }
-        
-        let progress = Progress(totalUnitCount: 1)
-        progress.setUserInfoObject(opType, forKey: .fileProvderOperationTypeKey)
-        progress.kind = .file
-        progress.setUserInfoObject(Progress.FileOperationKind.downloading, forKey: .fileOperationKindKey)
-        
-        request.set(httpAuthentication: credential, with: credentialType)
-        if let overwrite = overwrite, !overwrite {
-            request.setValue("F", forHTTPHeaderField: "Overwrite")
-        }
-        let task = session.dataTask(with: request, completionHandler: { (data, response, error) in
-            var responseError: FileProviderWebDavError?
-            if let response = response as? HTTPURLResponse, let code = FileProviderHTTPErrorCode(rawValue: response.statusCode) {
-                if response.statusCode >= 300  {
-                    responseError = FileProviderWebDavError(code: code, path: source, errorDescription: String(data: data ?? Data(), encoding: .utf8), url: sourceURL)
-                }
-                if code == .multiStatus, let data = data {
-                    let xresponses = DavResponse.parse(xmlResponse: data, baseURL: self.baseURL)
-                    for xresponse in xresponses where (xresponse.status ?? 0) >= 300 {
-                        let error = FileProviderWebDavError(code: code, path: source, errorDescription: String(data: data, encoding: .utf8), url: sourceURL)
-                        completionHandler?(error)
-                        progress.cancel()
-                    }
-                }
-            }
-            
-            if responseError == nil && error == nil {
-                progress.completedUnitCount = 1
-            } else {
-                progress.cancel()
-            }
-            
-            if (response as? HTTPURLResponse)?.statusCode ?? 0 != FileProviderHTTPErrorCode.multiStatus.rawValue {
-                completionHandler?(responseError ?? error)
-            }
-            
-            self.delegateNotify(opType, error: responseError ?? error)
-        })
-        task.taskDescription = opType.json
-        progress.cancellationHandler = { [weak task] in
-            task?.cancel()
-        }
-        progress.setUserInfoObject(Date(), forKey: .startingTimeKey)
-        task.resume()
-        return progress
-    }
-    
-    @discardableResult
-    open func copyItem(localFile: URL, to toPath: String, overwrite: Bool, completionHandler: SimpleCompletionHandler) -> Progress? {
-        // check file is not a folder
-        guard (try? localFile.resourceValues(forKeys: [.fileResourceTypeKey]))?.fileResourceType ?? .unknown == .regular else {
+    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?(self.throwError(localFile.path, code: URLError.fileIsDirectory))
+                completionHandler(nil, nil, nil, self.throwError(path, code: URLError.resourceUnavailable))
            }
-            return nil
+            return
        }
        
-        let opType = FileOperationType.copy(source: localFile.absoluteString, destination: toPath)
-        guard fileOperationDelegate?.fileProvider(self, shouldDoOperation: opType) ?? true == true else {
-            return nil
-        }
-        
-        var progress = Progress(parent: nil, userInfo: nil)
-        progress.setUserInfoObject(opType, forKey: .fileProvderOperationTypeKey)
-        progress.kind = .file
-        progress.setUserInfoObject(Progress.FileOperationKind.downloading, forKey: .fileOperationKindKey)
-        progress.totalUnitCount = localFile.fileSize
-        
-        let url = self.url(of:toPath)
-        var request = URLRequest(url: url)
-        if !overwrite {
-            request.setValue("F", forHTTPHeaderField: "Overwrite")
-        }
-        request.httpMethod = "PUT"
-        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 = (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)
-            }
-            if !(responseError == nil && error == nil) {
-                progress.cancel()
-            }
-            completionHandler?(responseError ?? error)
-            self?.delegateNotify(.create(path: toPath), error: responseError ?? error)
-        }
-        task.taskDescription = opType.json
-        task.addObserver(sessionDelegate!, forKeyPath: #keyPath(URLSessionTask.countOfBytesSent), options: .new, context: &progress)
-        progress.cancellationHandler = { [weak task] in
-            task?.cancel()
-        }
-        progress.setUserInfoObject(Date(), forKey: .startingTimeKey)
-        task.resume()
-        return progress
-    }
-    
-    @discardableResult
-    open func copyItem(path: String, toLocalURL destURL: URL, completionHandler: SimpleCompletionHandler) -> Progress? {
-        let opType = FileOperationType.copy(source: path, destination: destURL.absoluteString)
-        guard fileOperationDelegate?.fileProvider(self, shouldDoOperation: opType) ?? true == true else {
-            return nil
-        }
-        
-        var progress = Progress(parent: nil, userInfo: nil)
-        progress.setUserInfoObject(opType, forKey: .fileProvderOperationTypeKey)
-        progress.kind = .file
-        progress.setUserInfoObject(Progress.FileOperationKind.downloading, forKey: .fileOperationKindKey)
-        
-        let url = self.url(of:path)
-        var request = URLRequest(url: url)
-        request.set(httpAuthentication: credential, with: credentialType)
-        let task = session.downloadTask(with: request)
-        completionHandlersForTasks[session.sessionDescription!]?[task.taskIdentifier] = { error in
-            if error != nil {
-                progress.cancel()
-            }
-            completionHandler?(error)
-        }
-        downloadCompletionHandlersForTasks[session.sessionDescription!]?[task.taskIdentifier] = { tempURL in
-            guard let httpResponse = task.response as? HTTPURLResponse , httpResponse.statusCode < 300 else {
-                let code = FileProviderHTTPErrorCode(rawValue: (task.response as? HTTPURLResponse)?.statusCode ?? -1)
-                let serverError : FileProviderWebDavError? = code != nil ? FileProviderWebDavError(code: code!, path: path, errorDescription: code?.description, url: url) : nil
-                completionHandler?(serverError)
-                return
-            }
-            do {
-                try FileManager.default.moveItem(at: tempURL, to: destURL)
-                completionHandler?(nil)
-            } catch let e {
-                completionHandler?(e)
-            }
-        }
-        task.taskDescription = opType.json
-        task.addObserver(sessionDelegate!, forKeyPath: #keyPath(URLSessionTask.countOfBytesReceived), options: .new, context: &progress)
-        task.addObserver(sessionDelegate!, forKeyPath: #keyPath(URLSessionTask.countOfBytesExpectedToReceive), options: .new, context: &progress)
-        progress.cancellationHandler = { [weak task] in
-            task?.cancel()
-        }
-        progress.setUserInfoObject(Date(), forKey: .startingTimeKey)
-        task.resume()
-        return progress
-    }
-}
-
-extension WebDAVFileProvider: FileProviderReadWrite {
-    @discardableResult
-    open func contents(path: String, offset: Int64, length: Int, completionHandler: @escaping ((_ contents: Data?, _ error: Error?) -> Void)) -> Progress? {
-        if length == 0 || offset < 0 {
-            dispatch_queue.async {
-                completionHandler(Data(), nil)
-            }
-            return nil
-        }
-        
-        let opType = FileOperationType.fetch(path: path)
-        
-        var progress = Progress(parent: nil, userInfo: nil)
-        progress.setUserInfoObject(opType, forKey: .fileProvderOperationTypeKey)
-        progress.kind = .file
-        progress.setUserInfoObject(Progress.FileOperationKind.downloading, forKey: .fileOperationKindKey)
-        
        let url = self.url(of: path)
        var request = URLRequest(url: url)
+        request.httpMethod = "PROPPATCH"
        request.set(httpAuthentication: credential, with: credentialType)
-        request.set(rangeWithOffset: offset, length: length)
-        
-        let task = session.downloadTask(with: request)
-        completionHandlersForTasks[session.sessionDescription!]?[task.taskIdentifier] = { error in
-            if error != nil {
-                progress.cancel()
+        request.set(httpContentType: .xml, charset: .utf8)
+        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)
            }
-            
-            completionHandler(nil, error)
-        }
-        downloadCompletionHandlersForTasks[session.sessionDescription!]?[task.taskIdentifier] = { [weak self] 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
-            }
-            do {
-                let data = try Data(contentsOf: tempURL)
-                (self?.dispatch_queue ?? DispatchQueue.global()).async {
-                    completionHandler(data, nil)
+            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
                }
-            } catch let e {
-                completionHandler(nil, e)
            }
-        }
-        task.taskDescription = opType.json
-        task.addObserver(sessionDelegate!, forKeyPath: #keyPath(URLSessionTask.countOfBytesReceived), options: .new, context: &progress)
-        task.addObserver(sessionDelegate!, forKeyPath: #keyPath(URLSessionTask.countOfBytesExpectedToReceive), options: .new, context: &progress)
-        progress.cancellationHandler = { [weak task] in
-            task?.cancel()
-        }
-        progress.setUserInfoObject(Date(), forKey: .startingTimeKey)
-        task.resume()
-        return progress
+            completionHandler(nil, nil, nil, responseError ?? error)
+        })
    }
    
-    @discardableResult
-    open func writeContents(path: String, contents data: Data?, atomically: Bool, overwrite: Bool, completionHandler: SimpleCompletionHandler) -> Progress? {
-        let opType = FileOperationType.modify(path: path)
-        guard fileOperationDelegate?.fileProvider(self, shouldDoOperation: opType) ?? true == true else {
-            return nil
+    override func request(for operation: FileOperationType, overwrite: Bool = true, attributes: [URLResourceKey: Any] = [:]) -> URLRequest {
+        let method: String
+        let url: URL
+        let sourceURL = self.url(of: operation.source)
+        
+        switch operation {
+        case .fetch:
+            method = "GET"
+            url = sourceURL
+        case .create:
+            if sourceURL.absoluteString.hasSuffix("/") {
+                method = "MKCOL"
+                url = sourceURL
+            } else {
+                fallthrough
+            }
+        case .modify:
+            method = "PUT"
+            url = sourceURL
+            break
+        case .copy(let source, let dest):
+            if source.hasPrefix("file://") {
+                method = "PUT"
+                url = self.url(of: dest)
+            } else if dest.hasPrefix("file://") {
+                method = "GET"
+                url = sourceURL
+            } else {
+                method = "COPY"
+                url = sourceURL
+            }
+        case .move:
+            method = "MOVE"
+            url = sourceURL
+        case .remove:
+            method = "DELETE"
+            url = sourceURL
+        default:
+            fatalError("Unimplemented operation \(operation.description) in \(#file)")
        }
        
-        var progress = Progress(parent: nil, userInfo: nil)
-        progress.setUserInfoObject(opType, forKey: .fileProvderOperationTypeKey)
-        progress.kind = .file
-        progress.setUserInfoObject(Progress.FileOperationKind.downloading, forKey: .fileOperationKindKey)
-        progress.totalUnitCount = Int64(data?.count ?? 0)
-        
-        // FIXME: lock destination before writing process
-        let url = atomically ? self.url(of: path).appendingPathExtension("tmp") : self.url(of: path)
        var request = URLRequest(url: url)
-        request.httpMethod = "PUT"
+        request.httpMethod = method
        request.set(httpAuthentication: credential, with: credentialType)
-        if !overwrite {
-            request.setValue("F", forHTTPHeaderField: "Overwrite")
+        request.setValue(overwrite ? "T" : "F", forHTTPHeaderField: "Overwrite")
+        if let dest = operation.destination, !dest.hasPrefix("file://") {
+            request.setValue(self.url(of:dest).absoluteString, forHTTPHeaderField: "Destination")
        }
-        let task = session.uploadTask(with: request, from: data ?? Data())
-        completionHandlersForTasks[session.sessionDescription!]?[task.taskIdentifier] = { [weak self] error in
-            var responseError: FileProviderWebDavError?
-            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)
-            }
-            if !(responseError == nil && error == nil) {
-                progress.cancel()
-            }
-            completionHandler?(responseError ?? error)
-            self?.delegateNotify(opType, error: responseError ?? error)
+        
+        return request
+    }
+    
+    override func serverError(with code: FileProviderHTTPErrorCode, path: String?, data: Data?) -> FileProviderHTTPError {
+        return FileProviderWebDavError(code: code, path: path ?? "", errorDescription:  data.flatMap({ String(data: $0, encoding: .utf8) }), url: self.url(of: path ?? ""))
+    }
+    
+    override func multiStatusHandler(source: String, data: Data, completionHandler: SimpleCompletionHandler) {
+        let xresponses = DavResponse.parse(xmlResponse: data, baseURL: self.baseURL)
+        for xresponse in xresponses where (xresponse.status ?? 0) >= 300 {
+            let code = xresponse.status.flatMap { FileProviderHTTPErrorCode(rawValue: $0) } ?? .internalServerError
+            let error = FileProviderWebDavError(code: code, path: source, errorDescription: String(data: data, encoding: .utf8), url: self.url(of: source))
+            completionHandler?(error)
        }
-        task.taskDescription = opType.json
-        task.addObserver(sessionDelegate!, forKeyPath: #keyPath(URLSessionTask.countOfBytesSent), options: .new, context: &progress)
-        progress.cancellationHandler = { [weak task] in
-            task?.cancel()
-        }
-        progress.setUserInfoObject(Date(), forKey: .startingTimeKey)
-        task.resume()
-        return progress
    }
    
    /*
@@ -681,56 +389,8 @@ extension WebDAVFileProvider: ExtendedFileProvider {
    }
 }

-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 {
-    fileprivate func delegateNotify(_ operation: FileOperationType, error: Error?) {
-        DispatchQueue.main.async(execute: {
-            if error == nil {
-                self.delegate?.fileproviderSucceed(self, operation: operation)
-            } else {
-                self.delegate?.fileproviderFailed(self, operation: operation)
-            }
-        })
-    }
-}
-
 struct DavResponse {
    let href: URL
    let hrefString: String
@@ -741,7 +401,7 @@ struct DavResponse {
        
        func standardizePath(_ str: String) -> String {
            let trimmedStr = str.hasPrefix("/") ? str.substring(from: str.index(after: str.startIndex)) : str
-            return trimmedStr.addingPercentEncoding(withAllowedCharacters: CharacterSet.urlPathAllowed.subtracting(CharacterSet(charactersIn: ":"))) ?? str
+            return trimmedStr.addingPercentEncoding(withAllowedCharacters: .filePathAllowed) ?? str
        }
        
        // find node names with namespace
Author	SHA1	Message	Date
Amir Abbas	c7201a8be7	Fixed currentPath docs, delegateNotify method default error arg	2017-08-29 01:40:15 +04:30
Amir Abbas	d2a03369fd	Fixed FTP crash on rucursive remove	2017-08-28 00:06:02 +04:30
Amir Abbas	d08098008a	Removed FoundationErrorEnum, Refactoed delegate progress routine	2017-08-27 13:48:29 +04:30
Amir Abbas	3c5303214e	Fixed Array extension error in HashMAC	2017-08-24 15:08:22 +04:30
Amir Abbas	ad8f333d16	Fixed swift 3 compile error on Array extenson	2017-08-24 08:36:11 +04:30
Amir Abbas	5e8f653c52	Fixed compile bug in Swift 3.0 for Array.Iterator.Element	2017-08-23 23:21:17 +04:30
Amir Abbas	e4cd7ddf22	Fixed Quality<T> percision	2017-08-23 22:18:18 +04:30
Amir Abbas	1efb0e3fe5	Fixed Quality<T>	2017-08-23 22:15:45 +04:30
Amir Abbas	1292856646	Added convenience methods for URLRequest headers	2017-08-23 22:04:47 +04:30
Amir Abbas	e39f9c29ec	Merge commit '3d44de0b407c3cd604189cc161dc1fc039409763'	2017-08-23 10:54:59 +04:30
Amir Abbas	f43199c22a	fixed colon in url string problem across provider	2017-08-23 10:52:45 +04:30
Amir Abbas Mousavian	3d44de0b40	Added missed filePathAllowed const to CharacterSet	2017-08-23 01:22:19 +04:30
Amir Abbas	21b5214481	Deprecate currentPath property, returning error in provider delegate - Using checkResourceIsReachable to check file exists - fixed bug: downloading/uploading files with colon in name	2017-08-23 01:19:56 +04:30
Amir Abbas	f0b4925db2	Consistancy to delegate call in all contents(of:) methods - renamed opType instances to operation - moved to v2 in Dropbox - removed redundant CloudFileProvider methods	2017-08-20 22:41:53 +04:30
Amir Abbas	0da957d25f	Making protocol method implementations overridable	2017-08-19 19:47:54 +04:30
Amir Abbas	0de558c160	Recursive search fixed in FTP, OneDrive, WebDAV	2017-08-19 06:49:15 +04:30
Amir Abbas	cad68da076	Refactored Dropbox, WebDAV & OneDrive to HTTPFileProvider - FileOperationType.source is not optional anymore - critical bugfix: KVO exception crash on task completion	2017-08-19 05:51:25 +04:30
Amir Abbas Mousavian	39da09edd4	Merge pull request #60 from evilutioner/master Fixed file downloading progress	2017-08-15 18:53:21 +04:30
Amir Abbas	5129aee1b5	Added fileURL to Progress	2017-08-15 18:41:48 +04:30
Oleg Marchik	478f0819b5	Fixed file downloading progress	2017-08-15 16:57:50 +03:00