Merge pull request #246 from boostcampwm-2022/feature/refactoring-apple-signIn

Apple SignIn Proxy로 리팩토링

Author: ByeongjooYoo

Trinap/Sources/Presenter/Auth/SignIn/SignInViewController.swift

@@ -39,9 +39,7 @@ final class SignInViewController: BaseViewController {
     }
 
     // MARK: - Properties
-    private var currentNonce: String?
     private let viewModel: SignInViewModel
-    private let credentialSub = PublishSubject<(OAuthCredential, String)>()
 
     // MARK: - Initializers
     init(viewModel: SignInViewModel) {
@@ -82,22 +80,23 @@ final class SignInViewController: BaseViewController {
             make.centerX.equalToSuperview()
         }
     }
-        
+    
     override func bind() {
+        let credential = appleSignInButton.rx.tap
+            .asObservable()
+            .flatMap {
+                ASAuthorizationAppleIDProvider().rx.login(scope: [.email])
+            }
+            .withUnretained(self)
+            .compactMap { owner, authorization in
+                return owner.generateOAuthCredential(authorization: authorization)
+            }
+        
         let input = SignInViewModel.Input(
-            signInButtonTap: appleSignInButton.rx.tap.asObservable(),
-            credential: credentialSub.asObservable()
+            credential: credential
         )
         let output = viewModel.transform(input: input)
 
-        
-        output.presentSignInWithApple
-            .asObservable()
-            .subscribe { _ in
-                self.startSignInWithAppleFlow()
-            }
-            .disposed(by: disposeBag)
-        
         privacyPolicyButton.rx.tap
             .bind(onNext: { [weak self] _ in
                 self?.openPrivacyPolicy()
@@ -106,62 +105,35 @@ final class SignInViewController: BaseViewController {
     }
 }
 
-// MARK: - ASAuthorizationControllerDelegate
-extension SignInViewController: ASAuthorizationControllerDelegate {
-    func authorizationController(controller: ASAuthorizationController, didCompleteWithAuthorization authorization: ASAuthorization) {
+// MARK: - private Function
+private extension SignInViewController {
+    
+    private func generateOAuthCredential(authorization: ASAuthorization) -> (OAuthCredential, String)? {
         if let appleIDCredential = authorization.credential as? ASAuthorizationAppleIDCredential {
-            guard let nonce = currentNonce else {
-                fatalError("Invalid state: A login callback was received, but no login request was sent.")
-            }
+            let nonce = generateRandomNonce().toSha256()
+            
             guard let appleIDToken = appleIDCredential.identityToken else {
                 Logger.print("Unable to fetch identity token")
-                return
+                return nil
             }
             guard let idTokenString = String(data: appleIDToken, encoding: .utf8) else {
                 Logger.print("Unable to serialize token string from data: \(appleIDToken.debugDescription)")
-                return
+                return nil
             }
 
             guard
                 let authorizationCode = appleIDCredential.authorizationCode,
                 let codeString = String(data: authorizationCode, encoding: .utf8)
             else {
                 Logger.print("Unable to serialize token string from authorizationCode")
-                return
+                return nil
             }
 
             let credential = OAuthProvider.credential(withProviderID: "apple.com", idToken: idTokenString, rawNonce: nonce)
-            credentialSub.onNext((credential, codeString))
+            
+            return (credential, codeString)
         }
-    }
-}
-
-// MARK: - ASAuthorizationControllerPresentationContextProviding
-extension SignInViewController: ASAuthorizationControllerPresentationContextProviding {
-    func presentationAnchor(for controller: ASAuthorizationController) -> ASPresentationAnchor {
-        return self.view.window ?? ASPresentationAnchor()
-    }
-}
-
-// MARK: - private Function
-private extension SignInViewController {
-    func startSignInWithAppleFlow() {
-        let (request, nonce) = createRequest()
-        self.currentNonce = nonce
-        
-        let authorizationController = ASAuthorizationController(authorizationRequests: [request])
-        authorizationController.delegate = self
-        authorizationController.presentationContextProvider = self
-        authorizationController.performRequests()
-    }
-    
-    func createRequest() -> (ASAuthorizationAppleIDRequest, String) {
-        let nonce = self.generateRandomNonce()
-        let request = ASAuthorizationAppleIDProvider().createRequest()
-        request.requestedScopes = [.fullName, .email]
-        request.nonce = nonce.toSha256()
-        
-        return (request, nonce)
+        return nil
     }
 
     // Adapted from https://auth0.com/docs/api-auth/tutorials/nonce#generate-a-cryptographically-random-nonce

Trinap/Sources/Presenter/Auth/SignIn/SignInViewModel.swift

@@ -16,12 +16,10 @@ import RxSwift
 final class SignInViewModel: ViewModelType {
 
     struct Input {
-        let signInButtonTap: Observable<Void>
         let credential: Observable<(OAuthCredential, String)>
     }
 
     struct Output {
-        let presentSignInWithApple: Signal<Void>
         let signInFailure: Signal<Void>
     }
 
@@ -65,7 +63,6 @@ final class SignInViewModel: ViewModelType {
             .disposed(by: disposeBag)
 
         return Output(
-            presentSignInWithApple: input.signInButtonTap.asSignal(onErrorSignalWith: .empty()),
             signInFailure: signInFailure.asSignal()
         )
     }

Trinap/Sources/Presenter/Common/Extension/ASAuthorizationController+Rx.swift

@@ -0,0 +1,89 @@
+//
+//  ASAuthorizationController+Rx.swift
+//  Trinap
+//
+//  Created by ByeongJu Yu on 2022/12/27.
+//  Copyright © 2022 Trinap. All rights reserved.
+//
+
+import AuthenticationServices
+import RxSwift
+import RxCocoa
+
+class ASAuthorizationControllerProxy: DelegateProxy<ASAuthorizationController, ASAuthorizationControllerDelegate>, DelegateProxyType {
+    
+    // MARK: - Properties
+    private var presentationWindow = UIWindow()
+    internal lazy var didComplete = PublishSubject<ASAuthorization>()
+    
+    
+    // MARK: - Initializers
+    public init(controller: ASAuthorizationController) {
+        super.init(parentObject: controller, delegateProxy: ASAuthorizationControllerProxy.self)
+    }
+    
+    // MARK: - Methods
+    static func registerKnownImplementations() {
+        self.register {
+            ASAuthorizationControllerProxy(controller: $0)
+        }
+    }
+    
+    static func currentDelegate(for object: ASAuthorizationController) -> ASAuthorizationControllerDelegate? {
+        return object.delegate
+    }
+    
+    static func setCurrentDelegate(_ delegate: ASAuthorizationControllerDelegate?, to object: ASAuthorizationController) {
+        object.delegate = delegate
+    }
+    
+    // MARK: - Completed
+    deinit {
+        self.didComplete.onCompleted()
+    }
+}
+
+// MARK: - ASAuthorizationControllerDelegate
+extension ASAuthorizationControllerProxy: ASAuthorizationControllerDelegate {
+    
+    func authorizationController(
+        controller: ASAuthorizationController,
+        didCompleteWithAuthorization authorization: ASAuthorization
+    ) {
+        didComplete.onNext(authorization)
+        didComplete.onCompleted()
+    }
+    
+    func authorizationController(controller: ASAuthorizationController, didCompleteWithError error: Error) {
+        if (error as NSError).code == ASAuthorizationError.canceled.rawValue {
+            didComplete.onCompleted()
+            return
+        }
+        didComplete.onError(error)
+    }
+}
+
+// MARK: - ASAuthorizationControllerPresentationContextProviding
+extension ASAuthorizationControllerProxy: ASAuthorizationControllerPresentationContextProviding {
+    
+    func presentationAnchor(for controller: ASAuthorizationController) -> ASPresentationAnchor {
+        return self.presentationWindow
+    }
+}
+
+extension Reactive where Base: ASAuthorizationAppleIDProvider {
+    
+    public func login(scope: [ASAuthorization.Scope]? = nil) -> Observable<ASAuthorization> {
+        let request = base.createRequest()
+        request.requestedScopes = scope
+        
+        let controller = ASAuthorizationController(authorizationRequests: [request])
+        
+        let proxy = ASAuthorizationControllerProxy.proxy(for: controller)
+        
+        controller.presentationContextProvider = proxy
+        controller.performRequests()
+        
+        return proxy.didComplete
+    }
+}