Use URLSession delegate methods to allow background URLSessions in Tr…

…ansloaditKit (#39)

* Started migrating to a delegate based URLSession task system

* ensure callbacks are called and removed when no longer needed

* CI fixes

* Swift tools bump

* Various test fixes

Package.swift

@@ -1,4 +1,4 @@
-// swift-tools-version:5.3
+// swift-tools-version:5.5
 // The swift-tools-version declares the minimum version of Swift required to build this package.
 
 import PackageDescription

Sources/TransloaditKit/TransloaditAPI+URLSessionDelegate.swift

@@ -0,0 +1,27 @@
+import Foundation
+
+extension TransloaditAPI: URLSessionDataDelegate {
+  public func urlSession(_ session: URLSession, task: URLSessionTask, didCompleteWithError error: Error?) {
+    guard let completionHandler = callbacks[task] else { 
+      return
+    }
+
+    defer { callbacks[task] = nil }
+
+    if let error {
+      completionHandler.callback(.failure(error))
+      return
+    }
+
+    guard let response = task.response else {
+      completionHandler.callback(.failure(TransloaditAPIError.incompleteServerResponse))
+      return
+    }
+
+    completionHandler.callback(.success((completionHandler.data, response)))
+  }
+
+  public func urlSession(_ session: URLSession, dataTask: URLSessionDataTask, didReceive data: Data) {
+    callbacks[dataTask]?.data.append(data)
+  }
+}

Sources/TransloaditKit/TransloaditAPI.swift

@@ -14,18 +14,23 @@ enum TransloaditAPIError: Error {
     case couldNotFetchStatus
     case couldNotCreateAssembly(Error)
     case assemblyError(String)
+    case incompleteServerResponse
 }
 
 /// The `TransloaditAPI` class makes API calls, such as creating assemblies or checking an assembly's status.
-final class TransloaditAPI {
+final class TransloaditAPI: NSObject {
 
     private let basePath = URL(string: "https://api2.transloadit.com")!
 
     enum Endpoint: String {
         case assemblies = "/assemblies"
     }
 
-    private let session: URLSession
+    private let configuration: URLSessionConfiguration
+    private let delegateQueue: OperationQueue
+    private lazy var session: URLSession = {
+        return URLSession(configuration: configuration, delegate: self, delegateQueue: delegateQueue)
+    }()
 
     static private let formatter: DateFormatter = {
         let dateFormatter = DateFormatter()
@@ -36,10 +41,13 @@ final class TransloaditAPI {
     }()
 
     private let credentials: Transloadit.Credentials
+    var callbacks: [URLSessionTask: URLSessionCompletionHandler] = [:]
 
     init(credentials: Transloadit.Credentials, session: URLSession) {
         self.credentials = credentials
-        self.session = session
+        self.configuration = session.configuration
+        self.delegateQueue = session.delegateQueue
+        super.init()
     }
 
     func createAssembly(
@@ -60,13 +68,17 @@ final class TransloaditAPI {
             return
         }
 
-        let task = session.dataTask(with: request) { (data, response, error) in
-            if let data = data {
+        let task = session.dataTask(with: request)
+        callbacks[task] = URLSessionCompletionHandler(callback: { result in 
+            switch result {
+            case .failure(let error):
+                completion(.failure(.couldNotCreateAssembly(error)))
+            case .success((let data, _)):
                 do {
                     let decoder = JSONDecoder()
                     decoder.keyDecodingStrategy = .convertFromSnakeCase
                     let assembly = try decoder.decode(Assembly.self, from: data)
-                    
+
                     if let error = assembly.error {
                         completion(.failure(.assemblyError(error)))
                     } else {
@@ -76,7 +88,7 @@ final class TransloaditAPI {
                     completion(.failure(TransloaditAPIError.couldNotCreateAssembly(error)))
                 }
             }
-        }
+        })
         task.resume()
     }
 
@@ -98,13 +110,18 @@ final class TransloaditAPI {
             return
         }
 
-        let task = session.dataTask(with: request) { (data, response, error) in
-            if let data = data {
+        let task = session.dataTask(with: request)
+        //task.delegate = self
+        callbacks[task] = URLSessionCompletionHandler(callback: { result in
+            switch result {
+            case .failure(let error):
+                completion(.failure(.couldNotCreateAssembly(error)))
+            case .success((let data, _)):
                 do {
                     let decoder = JSONDecoder()
                     decoder.keyDecodingStrategy = .convertFromSnakeCase
                     let assembly = try decoder.decode(Assembly.self, from: data)
-                    
+
                     if let error = assembly.error {
                         completion(.failure(.assemblyError(error)))
                     } else {
@@ -114,7 +131,7 @@ final class TransloaditAPI {
                     completion(.failure(TransloaditAPIError.couldNotCreateAssembly(error)))
                 }
             }
-        }
+        })
         task.resume()
     }
 
@@ -268,9 +285,12 @@ final class TransloaditAPI {
             return request
         }
 
-        let task = session.dataTask(request: makeRequest()) { result in
+        let task = session.dataTask(with: makeRequest())
+        callbacks[task] = URLSessionCompletionHandler(callback: { result in
             switch result {
-            case .success((let data?, _)):
+            case .failure:
+                completion(.failure(.couldNotFetchStatus))
+            case .success((let data, _)):
                 do {
                     let decoder = JSONDecoder()
                     decoder.keyDecodingStrategy = .convertFromSnakeCase
@@ -279,13 +299,8 @@ final class TransloaditAPI {
                 } catch {
                     completion(.failure(.couldNotFetchStatus))
                 }
-            case .success((nil, _)):
-                completion(.failure(.couldNotFetchStatus))
-            case .failure:
-                completion(.failure(.couldNotFetchStatus))
             }
-        }
-
+        })
         task.resume()
     }
 
@@ -296,9 +311,12 @@ final class TransloaditAPI {
             return request
         }
 
-        let task = session.dataTask(request: makeRequest()) { result in
+        let task = session.dataTask(with: makeRequest())
+        callbacks[task] = URLSessionCompletionHandler(callback: { result in
             switch result {
-            case .success((let data?, _)):
+            case .failure:
+                completion(.failure(.couldNotFetchStatus))
+            case .success((let data, _)):
                 do {
                     let decoder = JSONDecoder()
                     decoder.keyDecodingStrategy = .convertFromSnakeCase
@@ -307,13 +325,8 @@ final class TransloaditAPI {
                 } catch {
                     completion(.failure(.couldNotFetchStatus))
                 }
-            case .success((nil, _)):
-                completion(.failure(.couldNotFetchStatus))
-            case .failure:
-                completion(.failure(.couldNotFetchStatus))
             }
-        }
-
+        })
         task.resume()
     }
 }

Sources/TransloaditKit/URLSessionCompletionHandler.swift

@@ -0,0 +1,11 @@
+import Foundation
+
+class URLSessionCompletionHandler {
+  var data: Data
+  let callback: (Result<(Data, URLResponse), Error>) -> Void
+
+  init(callback: @escaping (Result<(Data, URLResponse), Error>) -> Void) {
+    self.callback = callback
+    self.data = Data()
+  }
+}

Tests/TransloaditKitTests/Fixtures.swift

@@ -13,7 +13,7 @@ enum Fixtures {
     // We make Assembly and AssemblyStatus here because we can access their initializers (via testable import). Which we can't in TransloaditKitTests (on purpose to test public API). We have no need to expose the memberwise initializers from these types to the public API either.
 
     static func makeAssembly() -> Assembly {
-        Assembly(id: "abc", error: nil, tusURL: URL(string: "https://my-tus.transloadit.com")!, url: URL(string: "https://transloadit.com")!)
+        Assembly(id: UUID().uuidString, error: nil, tusURL: URL(string: "https://my-tus.transloadit.com")!, url: URL(string: "https://transloadit.com")!)
     }
 
     static func makeAssemblyStatus(status: AssemblyStatus.ProcessingStatus) -> AssemblyStatus {

Tests/TransloaditKitTests/Support.swift

@@ -23,7 +23,7 @@ enum Files {
 
     static func storeFile(data: Data) throws -> URL {
         let docDir = FileManager.default.urls(for: .documentDirectory, in: .userDomainMask)[0]
-        let targetLocation = docDir.appendingPathComponent("myfile.txt")
+        let targetLocation = docDir.appendingPathComponent("\(UUID().uuidString).txt")
         try data.write(to: targetLocation)
         return targetLocation
     }
@@ -58,7 +58,7 @@ enum Network {
     }
 
     static func prepareForStatusResponse(data: Data) {
-        let url = URL(string: "www.tus-image-upload-location-returned-for-creation-post.com")!
+        let url = URL(string: "https://my-tus.transloadit.com/www.tus-image-upload-location-returned-for-creation-post.com")!
         MockURLProtocol.prepareResponse(for: url, method: "HEAD") { _ in
             MockURLProtocol.Response(status: 200, headers: ["Upload-Length": String(data.count),
                                                             "Upload-Offset": "0"], data: nil)
@@ -73,7 +73,7 @@ enum Network {
     }
 
     static func prepareForSuccesfulUploads(url: URL, data: Data, lowerCasedKeysInResponses: Bool = false) {
-        let uploadURL = URL(string: "www.tus-image-upload-location-returned-for-creation-post.com")!
+        let uploadURL = URL(string: "https://my-tus.transloadit.com/www.tus-image-upload-location-returned-for-creation-post.com")!
         MockURLProtocol.prepareResponse(for: url, method: "POST") { _ in
             let key: String
             if lowerCasedKeysInResponses {

Tests/TransloaditKitTests/TransloaditKitTests.swift

@@ -134,7 +134,6 @@ final class TransloaditKitTests: XCTestCase {
 
         var localAssembly: Assembly!
         transloadit.createAssembly(steps: [resizeStep], andUpload: files, completion: { result in
-
             switch result {
             case .success(let assembly):
                 localAssembly = assembly
@@ -146,13 +145,15 @@ final class TransloaditKitTests: XCTestCase {
         wait(for: [startedUploadsExpectation], timeout: 3)
 
         transloadit.stopRunningUploads()
-
         // Restart uploads, continue where left off
 
-        fileDelegate.finishUploadExpectation = finishedUploadExpectation
-        transloadit.start()
+        DispatchQueue.main.asyncAfter(deadline: .now() + 1) { [self] in
+            fileDelegate.startUploadExpectation = nil
+            fileDelegate.finishUploadExpectation = finishedUploadExpectation
+            transloadit.start()
+        }
 
-        wait(for: [finishedUploadExpectation], timeout: 5)
+        wait(for: [finishedUploadExpectation], timeout: 10)
 
         XCTAssert(fileDelegate.finishedUploads.contains(localAssembly))
     }
@@ -186,15 +187,19 @@ final class TransloaditKitTests: XCTestCase {
 
         let secondTransloadit = makeClient()
         let secondFileDelegate = TransloadItMockDelegate()
-
         secondTransloadit.fileDelegate = secondFileDelegate
         secondFileDelegate.name = "SECOND"
+
+
 
         let finishedUploadExpectation = self.expectation(description: "Finished file upload")
         finishedUploadExpectation.expectedFulfillmentCount = numFiles
 
         secondFileDelegate.finishUploadExpectation = finishedUploadExpectation
-        secondTransloadit.start()
+
+        DispatchQueue.main.asyncAfter(deadline: .now() + 1) {
+            secondTransloadit.start()    
+        }
 
         wait(for: [finishedUploadExpectation], timeout: 5)
 

TransloaditKitExample/TransloaditKitExample/PhotoPicker.swift

@@ -18,7 +18,6 @@ struct PhotoPicker: UIViewControllerRepresentable {
     func makeUIViewController(context: Context) -> PHPickerViewController {
         var configuration = PHPickerConfiguration(photoLibrary: PHPhotoLibrary.shared())
         configuration.selectionLimit = 30
-        configuration.filter = .images
 
         let picker = PHPickerViewController(configuration: configuration)
         picker.delegate = context.coordinator

TransloaditKitExample/TransloaditKitExample/TransloaditKitExampleApp.swift

@@ -12,6 +12,26 @@ import Atlantis
 final class MyUploader: ObservableObject {
     let transloadit: Transloadit
 
+    func upload2(_ urls: [URL]) {
+        let templateID = "1a84d2f1f2584f92981bda285bbc4e84"
+
+        transloadit.createAssembly(templateId: templateID, andUpload: urls, customFields: ["hello": "world"]) { result in
+            switch result {
+            case .success(let assembly):
+                print("Retrieved \(assembly)")
+            case .failure(let error):
+                print("Assembly error \(error)")
+            }
+        }.pollAssemblyStatus { result in
+            switch result {
+            case .success(let assemblyStatus):
+                print("Received assemblystatus \(assemblyStatus)")
+            case .failure(let error):
+                print("Caught polling error \(error)")
+            }
+        }
+    }
+
     func upload(_ urls: [URL]) {
         let resizeStep = StepFactory.makeResizeStep(width: 200, height: 100)
         transloadit.createAssembly(steps: [resizeStep], andUpload: urls, customFields: ["hello": "world"]) { result in
@@ -32,7 +52,7 @@ final class MyUploader: ObservableObject {
     }
 
     init() {
-        let credentials = Transloadit.Credentials(key: "my_key", secret: "my_secret")
+        let credentials = Transloadit.Credentials(key: "Ru1rwq3ITrgSEDtgna6SGZa4yY71YJgW", secret: "Xo6xlnn42cfBkNxLSDWJNCQoSNL0j1aFB9wNyaAR")
         self.transloadit = Transloadit(credentials: credentials, session: URLSession.shared)
         self.transloadit.fileDelegate = self
     }
@@ -90,7 +110,7 @@ struct TransloaditKitExampleApp: App {
 
     init() {
         self.uploader = MyUploader()
-        // Atlantis.start(hostName: "")
+        Atlantis.start(hostName: "donnys-macbook-pro-2.local.")
     }
 
     var body: some Scene {