Add FileCDN class enable generating signedURL's in File Attachments (#620)

Author: bpollman

Sources/StreamChatSwiftUI/ChatChannel/MessageList/FileAttachmentPreview.swift

@@ -10,9 +10,15 @@ public struct FileAttachmentPreview: View {
 
     @Injected(\.fonts) private var fonts
     @Injected(\.images) private var images
+    @Injected(\.utils) private var utils
+
+    private var fileCDN: FileCDN {
+        utils.fileCDN
+    }
 
     var url: URL
 
+    @State var adjustedUrl: URL?
     @State private var isLoading = false
     @State private var title: String?
     @State private var error: Error?
@@ -25,18 +31,31 @@ public struct FileAttachmentPreview: View {
                         .font(fonts.body)
                         .padding()
                 } else {
-                    WebView(
-                        url: url,
-                        isLoading: $isLoading,
-                        title: $title,
-                        error: $error
-                    )
+
+                    if let adjustedUrl = adjustedUrl {
+                        WebView(
+                            url: adjustedUrl,
+                            isLoading: $isLoading,
+                            title: $title,
+                            error: $error
+                        )
+                    }
 
                     if isLoading {
                         ProgressView()
                     }
                 }
             }
+            .onAppear {
+                fileCDN.adjustedURL(for: url) { result in
+                    switch result {
+                    case let .success(url):
+                        self.adjustedUrl = url
+                    case let .failure(error):
+                        self.error = error
+                    }
+                }
+            }
             .navigationBarTitleDisplayMode(.inline)
             .toolbar {
                 ToolbarItem(placement: .principal) {

Sources/StreamChatSwiftUI/Utils.swift

@@ -14,6 +14,7 @@ public class Utils {
     public var imageCDN: ImageCDN
     public var imageProcessor: ImageProcessor
     public var imageMerger: ImageMerging
+    public var fileCDN: FileCDN
     public var channelNamer: ChatChannelNamer
     public var chatUserNamer: ChatUserNamer
     public var channelAvatarsMerger: ChannelAvatarsMerging
@@ -69,6 +70,7 @@ public class Utils {
         imageCDN: ImageCDN = StreamImageCDN(),
         imageProcessor: ImageProcessor = NukeImageProcessor(),
         imageMerger: ImageMerging = DefaultImageMerger(),
+        fileCDN: FileCDN = DefaultFileCDN(),
         channelAvatarsMerger: ChannelAvatarsMerging = ChannelAvatarsMerger(),
         messageTypeResolver: MessageTypeResolving = MessageTypeResolver(),
         messageActionResolver: MessageActionsResolving = MessageActionsResolver(),
@@ -92,6 +94,7 @@ public class Utils {
         self.imageCDN = imageCDN
         self.imageProcessor = imageProcessor
         self.imageMerger = imageMerger
+        self.fileCDN = fileCDN
         self.channelNamer = channelNamer
         self.chatUserNamer = chatUserNamer
         self.channelAvatarsMerger = channelAvatarsMerger

Sources/StreamChatSwiftUI/Utils/Common/FileCDN.swift

@@ -0,0 +1,32 @@
+//
+// Copyright © 2024 Stream.io Inc. All rights reserved.
+//
+
+import Foundation
+import StreamChat
+
+/// A protocol the video preview uploader implementation must conform to.
+public protocol FileCDN: AnyObject {
+    /// Prepare and return an adjusted or  signed `URL` for the given file `URL`
+    /// This function can be used to intercept an unsigned URL and return a valid signed URL
+    /// - Parameters:
+    ///   - url: A file URL.
+    ///   - completion: A completion that is called when an adjusted URL is ready to be provided.
+    func adjustedURL(
+        for url: URL,
+        completion: @escaping ((Result<URL, Error>) -> Void)
+    )
+}
+
+/// The `DefaultFileCDN` implemenation used by default.
+public final class DefaultFileCDN: FileCDN {
+
+    // Initializer required for subclasses
+    public init() {
+        // Public init.
+    }
+
+    public func adjustedURL(for url: URL, completion: @escaping ((Result<URL, any Error>) -> Void)) {
+        completion(.success(url))
+    }
+}

StreamChatSwiftUI.xcodeproj/project.pbxproj

@@ -490,6 +490,7 @@
 		91B79FD9284E7E9C005B6E4F /* ChatUserNamer_Tests.swift in Sources */ = {isa = PBXBuildFile; fileRef = 91B79FD8284E7E9C005B6E4F /* ChatUserNamer_Tests.swift */; };
 		91CC203A283C3E7F0049A146 /* URLExtensions.swift in Sources */ = {isa = PBXBuildFile; fileRef = 91CC2039283C3E7F0049A146 /* URLExtensions.swift */; };
 		91CC203C283C4C250049A146 /* URLUtils_Tests.swift in Sources */ = {isa = PBXBuildFile; fileRef = 91CC203B283C4C250049A146 /* URLUtils_Tests.swift */; };
+		9D9A54512CB89EAA00A76D9E /* FileCDN.swift in Sources */ = {isa = PBXBuildFile; fileRef = 9D9A54502CB89EAA00A76D9E /* FileCDN.swift */; };
 		A35D803B283E89F50084FE25 /* StreamChatSwiftUI.framework in Frameworks */ = {isa = PBXBuildFile; fileRef = 8465FBB52746873A00AF091E /* StreamChatSwiftUI.framework */; };
 		A35D803C283E89F50084FE25 /* StreamChatSwiftUI.framework in Embed Frameworks */ = {isa = PBXBuildFile; fileRef = 8465FBB52746873A00AF091E /* StreamChatSwiftUI.framework */; settings = {ATTRIBUTES = (CodeSignOnCopy, RemoveHeadersOnCopy, ); }; };
 		A3600B2A283E9E1900E1C930 /* UserRobot.swift in Sources */ = {isa = PBXBuildFile; fileRef = A3600B24283E9E1900E1C930 /* UserRobot.swift */; };
@@ -1060,6 +1061,7 @@
 		91B79FD8284E7E9C005B6E4F /* ChatUserNamer_Tests.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = ChatUserNamer_Tests.swift; sourceTree = "<group>"; };
 		91CC2039283C3E7F0049A146 /* URLExtensions.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = URLExtensions.swift; sourceTree = "<group>"; };
 		91CC203B283C4C250049A146 /* URLUtils_Tests.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = URLUtils_Tests.swift; sourceTree = "<group>"; };
+		9D9A54502CB89EAA00A76D9E /* FileCDN.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = FileCDN.swift; sourceTree = "<group>"; };
 		A3600B24283E9E1900E1C930 /* UserRobot.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = UserRobot.swift; sourceTree = "<group>"; };
 		A3600B29283E9E1900E1C930 /* UserRobot+Asserts.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = "UserRobot+Asserts.swift"; sourceTree = "<group>"; };
 		A3600B31283E9E4700E1C930 /* MessageList_Tests.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = MessageList_Tests.swift; sourceTree = "<group>"; };
@@ -1838,6 +1840,7 @@
 				91B79FD6284E21E0005B6E4F /* ChatUserNamer.swift */,
 				8465FD3A2746A95600AF091E /* DateFormatter+Extensions.swift */,
 				8465FD402746A95600AF091E /* DateUtils.swift */,
+				9D9A54502CB89EAA00A76D9E /* FileCDN.swift */,
 				8465FD3D2746A95600AF091E /* ImageCDN.swift */,
 				8465FD482746A95600AF091E /* ImageMerger.swift */,
 				8465FD422746A95600AF091E /* InputTextView.swift */,
@@ -2708,6 +2711,7 @@
 				8482094E2ACFFCD900EF3261 /* Throttler.swift in Sources */,
 				84EADEBD2B28C2EC0046B50C /* RecordingState.swift in Sources */,
 				4F7DD9A02BFC7C6100599AA6 /* ChatClient+Extensions.swift in Sources */,
+				9D9A54512CB89EAA00A76D9E /* FileCDN.swift in Sources */,
 				82D64C1B2AD7E5B700C5C79E /* ImageCaching.swift in Sources */,
 				82D64C062AD7E5B700C5C79E /* Graphics.swift in Sources */,
 				8465FDCB2746A95700AF091E /* ChatChannelListView.swift in Sources */,