WIP Add SwiftUI Quickstart for Storage

storage/Podfile

@@ -1,15 +1,29 @@
 # StorageExample
 
 use_frameworks!
-platform :ios, '10.0'
-
-pod 'Firebase/Analytics'
-pod 'Firebase/Auth'
-pod 'Firebase/Storage'
 
 target 'StorageExample' do
+  platform :ios, '10.0'
+
+  pod 'Firebase/Analytics'
+  pod 'Firebase/Auth'
+  pod 'Firebase/Storage'
 end
 target 'StorageExampleSwift' do
+  platform :ios, '10.0'
+
+  pod 'Firebase/Analytics'
+  pod 'Firebase/Auth'
+  pod 'Firebase/Storage'
+  pod 'FirebaseStorageSwift', "~> 7.0-beta"
+end
+target 'StorageExampleSwiftUI' do
+  platform :ios, '13.0'
+
+  pod 'Firebase'
+  pod 'Firebase/Analytics'
+  pod 'Firebase/Auth'
+  pod 'Firebase/Storage'
   pod 'FirebaseStorageSwift', "~> 7.0-beta"
 end
 target 'StorageExampleTests' do

storage/Podfile.lock

@@ -1,4 +1,6 @@
 PODS:
+  - Firebase (7.4.0):
+    - Firebase/Core (= 7.4.0)
   - Firebase/Analytics (7.4.0):
     - Firebase/Core
   - Firebase/Auth (7.4.0):
@@ -81,6 +83,7 @@ PODS:
   - PromisesObjC (1.2.12)
 
 DEPENDENCIES:
+  - Firebase
   - Firebase/Analytics
   - Firebase/Auth
   - Firebase/Storage
@@ -119,6 +122,6 @@ SPEC CHECKSUMS:
   nanopb: 59221d7f958fb711001e6a449489542d92ae113e
   PromisesObjC: 3113f7f76903778cf4a0586bd1ab89329a0b7b97
 
-PODFILE CHECKSUM: 68e67a7f5b716247bf88b244cb2b3cc55d2e53ec
+PODFILE CHECKSUM: 25b9e14f35ae5e264d830941bf9f0c8c3b02ce6b
 
 COCOAPODS: 1.10.1

storage/StorageExampleSwiftUI/ImagePicker.swift

@@ -0,0 +1,100 @@
+// Copyright 2021 Google LLC
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+import SwiftUI
+import Firebase
+
+/// ImagePickerRepresentable wraps a UIImagePickerController, so it is accessible through SwiftUI.
+struct ImagePickerRepresentable {
+  enum Source {
+    case camera
+    case photoLibrary
+  }
+
+  /// Denotes whether the user is taking a photo or selecting one.
+  var source: Source
+
+  /// Persistent storage which retains the image.
+  @ObservedObject var store: ImageStore
+
+  /// Binds to whether the image picker is visible.
+  @Binding var visible: Bool
+
+  /// Completion handler that is invoked when the image picker dismisses.
+  var completion: () -> Void
+
+  /// Coordinator is an internal class that acts as a delegate for the image picker.
+  class Coordinator: NSObject {
+    private var representable: ImagePickerRepresentable
+    private var store: ImageStore
+
+    init(representable: ImagePickerRepresentable, store: ImageStore) {
+      self.representable = representable
+      self.store = store
+    }
+  }
+}
+
+extension ImagePickerRepresentable: UIViewControllerRepresentable {
+  typealias UIViewControllerType = UIImagePickerController
+
+  /// Invoked by the system to setup a coordinator that the UIImagePickerViewController can use.
+  /// - Returns: The coordinator.
+  func makeCoordinator() -> Coordinator {
+    Coordinator(representable: self, store: self.store)
+  }
+
+  func makeUIViewController(context: Context) -> UIImagePickerController {
+    let imagePicker = UIImagePickerController()
+
+    switch self.source {
+    case .camera:
+      imagePicker.sourceType = .camera
+      imagePicker.cameraCaptureMode = .photo
+    case .photoLibrary:
+      imagePicker.sourceType = .photoLibrary
+    }
+
+    imagePicker.delegate = context.coordinator
+    return imagePicker
+  }
+
+  /// Required to implement, but unnecessary. We do not need to invalidate the SwiftUI canvas.
+  func updateUIViewController(_ uiViewController: UIImagePickerController, context: Context) { }
+}
+
+extension ImagePickerRepresentable.Coordinator: UIImagePickerControllerDelegate {
+  func imagePickerController(
+    _ picker: UIImagePickerController,
+    didFinishPickingMediaWithInfo info: [UIImagePickerController.InfoKey : Any]
+  ) {
+    if let image = info[UIImagePickerController.InfoKey.originalImage] as? UIImage {
+      // TODO: Consider displaying a progress bar or spinner here
+      store.saveImage(image) { result in
+        // TODO: Handle the error
+        self.representable.visible = false
+        picker.dismiss(animated: true, completion: self.representable.completion)
+      }
+    }
+  }
+
+  func imagePickerControllerDidCancel(_ picker: UIImagePickerController) {
+    self.representable.visible = false
+    picker.dismiss(animated: true, completion: self.representable.completion)
+  }
+}
+
+/// The coordinator must implement the UINavigationControllerDelegate protocol in order to be the
+/// UIImagePickerController's delegate.
+extension ImagePickerRepresentable.Coordinator: UINavigationControllerDelegate { }

storage/StorageExampleSwiftUI/ImageStore.swift

@@ -0,0 +1,99 @@
+// Copyright 2021 Google LLC
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+import Firebase
+import FirebaseStorageSwift
+
+/// ImageStore facilitates saving and loading an image.
+public class ImageStore: ObservableObject {
+  /// Reference to Firebase storage.
+  private var storage: Storage
+
+  /// Quality for JPEG images where 1.0 is the best quality and 0.0 is the worst.
+  public var compressionQuality: CGFloat = 0.8
+
+  /// UserDefaults key that will have a value containing the path of the last image.
+  public let imagePathKey = "imagePath"
+
+  /// Binds to the current image.
+  @Published var image: UIImage?
+
+  lazy var localImageFileDirectory: String = {
+    let paths = NSSearchPathForDirectoriesInDomains(.documentDirectory, .userDomainMask, true)
+    let documentsDirectory = paths[0]
+    return "file:\(documentsDirectory)"
+  }()
+
+  public init(storage: Storage) {
+    self.storage = storage
+  }
+
+  /// Saves an image in the store.
+  /// - Parameter image: The image to save.
+  public func saveImage(_ image: UIImage, completion: @escaping (Result<Void, Error>) -> Void) {
+    self.image = image
+    let imagePath = "\(Auth.auth().currentUser!.uid)/\(Int(Date.timeIntervalSinceReferenceDate * 1000)).jpg"
+    uploadImage(image, atPath: imagePath) { result in
+      UserDefaults.standard.setValue(imagePath, forKey: self.imagePathKey)
+      completion(result)
+    }
+  }
+
+  /// Loads the most recent image.
+  public func loadImage() {
+    if let imagePath = UserDefaults.standard.string(forKey: imagePathKey) {
+      downloadImage(atPath: imagePath)
+    }
+  }
+
+  /// Uploads an image to Firebase storage.
+  /// - Parameters:
+  ///   - image: Image to upload.
+  ///   - imagePath: Path of the image in Firebase storage.
+  private func uploadImage(
+    _ image: UIImage,
+    atPath imagePath: String,
+    completion: @escaping (Result<Void, Error>) -> Void
+  ) {
+    guard let imageData = image.jpegData(compressionQuality: compressionQuality) else { return }
+
+    let imageMetadata = StorageMetadata()
+    imageMetadata.contentType = "image/jpeg"
+
+    let storageRef = storage.reference(withPath: imagePath)
+    storageRef.putData(imageData, metadata: imageMetadata) { result in
+      switch result {
+      case .success:
+        completion(.success(()))
+      case let .failure(error):
+        completion(.failure(error))
+        break
+      }
+    }
+  }
+
+  /// Downloads an image from Firebase storage.
+  /// - Parameter imagePath: Path of the image in Firebase storage.
+  private func downloadImage(atPath imagePath: String) {
+    guard let imageURL = URL(string: "\(self.localImageFileDirectory)/\(imagePath)") else { return }
+    self.storage.reference().child(imagePath).write(toFile: imageURL) { result in
+      switch result {
+      case let .success(downloadedFileURL):
+        self.image = UIImage(contentsOfFile: downloadedFileURL.path)
+      case let .failure(error):
+        print("Error downloading: \(error)")
+      }
+    }
+  }
+}

storage/StorageExampleSwiftUI/ImageView.swift

@@ -0,0 +1,94 @@
+// Copyright 2021 Google LLC
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+import SwiftUI
+import Firebase
+
+/// ImageView provides the main content for the app. It displays a current image and provides
+/// controls to change it by taking a new one with the camera, selecting one from the photo library
+/// or downloading one from Firebase storage.
+struct ImageView: View {
+  /// Manages retrieval and persistence of the current image.
+  @StateObject private var photoStore = ImageStore(storage: Storage.storage())
+
+  /// Indicates whether the user is selecting an image from the photo library.
+  @State var isSelectingImage = false
+
+  /// Indicates whether the user is taking an image using the camera.
+  @State var isTakingPhoto = false
+
+  /// Indicates whether a submenu that allows the user to choose whether to select or take a photo
+  /// should be visible.
+  @State var showUploadMenu = false
+
+  var body: some View {
+    NavigationView {
+      VStack {
+        Image(uiImage: photoStore.image ?? UIImage())
+          .resizable()
+          .aspectRatio(contentMode: .fit)
+      }
+      .navigationTitle("Firebase Storage")
+      .toolbar {
+        ToolbarItemGroup(placement: .bottomBar) {
+          if showUploadMenu {
+            Button("❌") {
+              showUploadMenu = false
+            }
+
+            Spacer()
+
+            Button("Take Photo") {
+              isTakingPhoto = true
+            }.sheet(isPresented: $isTakingPhoto) {
+              ImagePickerRepresentable(
+                source: .camera,
+                store: photoStore,
+                visible: $isTakingPhoto
+              ) {
+                showUploadMenu = false
+              }
+            }.disabled(!UIImagePickerController.isSourceTypeAvailable(.camera))
+
+            Button("Select Image") {
+              isSelectingImage = true
+            }.sheet(isPresented: $isSelectingImage) {
+              ImagePickerRepresentable(
+                source: .photoLibrary,
+                store: photoStore,
+                visible: $isSelectingImage
+              ) {
+                showUploadMenu = false
+              }
+            }
+          } else {
+            Button("Upload") {
+              showUploadMenu = true
+            }
+            Spacer()
+            Button("Download") {
+              photoStore.loadImage()
+            }
+          }
+        }
+      }
+    }
+  }
+}
+
+struct ContentView_Previews: PreviewProvider {
+  static var previews: some View {
+    ImageView()
+  }
+}