packages/google_sign_in/ios/Classes/GoogleSignInPlugin.m

// Copyright 2017, the Flutter project authors.  Please see the AUTHORS file
// for details. All rights reserved. Use of this source code is governed by a
// BSD-style license that can be found in the LICENSE file.

#import "GoogleSignInPlugin.h"
#import <GoogleSignIn/GoogleSignIn.h>

// The key within `GoogleService-Info.plist` used to hold the application's
// client id.  See https://developers.google.com/identity/sign-in/ios/start
// for more info.
static NSString *const kClientIdKey = @"CLIENT_ID";

@interface NSError (FlutterError)
@property(readonly, nonatomic) FlutterError *flutterError;
@end

@implementation NSError (FlutterError)
- (FlutterError *)flutterError {
  return [FlutterError errorWithCode:[NSString stringWithFormat:@"%ld", (long)self.code]
                             message:self.domain
                             details:self.localizedDescription];
}
@end

@interface GoogleSignInPlugin ()<GIDSignInDelegate, GIDSignInUIDelegate>
@end

@implementation GoogleSignInPlugin {
  NSMutableArray<FlutterResult> *_accountRequests;
}

+ (void)registerWithRegistrar:(NSObject<FlutterPluginRegistrar> *)registrar {
  FlutterMethodChannel *channel =
      [FlutterMethodChannel methodChannelWithName:@"plugins.flutter.io/google_sign_in"
                                  binaryMessenger:[registrar messenger]];
  GoogleSignInPlugin *instance = [[GoogleSignInPlugin alloc] init];
  [registrar addApplicationDelegate:instance];
  [registrar addMethodCallDelegate:instance channel:channel];
}

- (instancetype)init {
  self = [super init];
  if (self) {
    _accountRequests = [[NSMutableArray alloc] init];
    [GIDSignIn sharedInstance].delegate = self;
    [GIDSignIn sharedInstance].uiDelegate = self;

    // On the iOS simulator, we get "Broken pipe" errors after sign-in for some
    // unknown reason. We can avoid crashing the app by ignoring them.
    signal(SIGPIPE, SIG_IGN);
  }
  return self;
}

#pragma mark - <FlutterPlugin> protocol

- (void)handleMethodCall:(FlutterMethodCall *)call result:(FlutterResult)result {
  if ([call.method isEqualToString:@"init"]) {
    NSString *path = [[NSBundle mainBundle] pathForResource:@"GoogleService-Info" ofType:@"plist"];
    if (path) {
      NSMutableDictionary *plist = [[NSMutableDictionary alloc] initWithContentsOfFile:path];
      [GIDSignIn sharedInstance].clientID = plist[kClientIdKey];
      [GIDSignIn sharedInstance].scopes = call.arguments[@"scopes"];
      [GIDSignIn sharedInstance].hostedDomain = call.arguments[@"hostedDomain"];
      result(nil);
    } else {
      result([FlutterError errorWithCode:@"missing-config"
                                 message:@"GoogleService-Info.plist file not found"
                                 details:nil]);
    }
  } else if ([call.method isEqualToString:@"signInSilently"]) {
    [_accountRequests insertObject:result atIndex:0];
    [[GIDSignIn sharedInstance] signInSilently];
  } else if ([call.method isEqualToString:@"signIn"]) {
    [_accountRequests insertObject:result atIndex:0];
    [[GIDSignIn sharedInstance] signIn];
  } else if ([call.method isEqualToString:@"getTokens"]) {
    GIDGoogleUser *currentUser = [GIDSignIn sharedInstance].currentUser;
    GIDAuthentication *auth = currentUser.authentication;
    [auth getTokensWithHandler:^void(GIDAuthentication *authentication, NSError *error) {
      result(error != nil ? error.flutterError : @{
        @"idToken" : authentication.idToken,
        @"accessToken" : authentication.accessToken,
      });
    }];
  } else if ([call.method isEqualToString:@"signOut"]) {
    [[GIDSignIn sharedInstance] signOut];
    result(nil);
  } else if ([call.method isEqualToString:@"disconnect"]) {
    [_accountRequests insertObject:result atIndex:0];
    [[GIDSignIn sharedInstance] disconnect];
  } else {
    result(FlutterMethodNotImplemented);
  }
}

- (BOOL)application:(UIApplication *)app openURL:(NSURL *)url options:(NSDictionary *)options {
  NSString *sourceApplication = options[UIApplicationOpenURLOptionsSourceApplicationKey];
  id annotation = options[UIApplicationOpenURLOptionsAnnotationKey];
  return [[GIDSignIn sharedInstance] handleURL:url
                             sourceApplication:sourceApplication
                                    annotation:annotation];
}

#pragma mark - <GIDSignInUIDelegate> protocol

- (void)signIn:(GIDSignIn *)signIn presentViewController:(UIViewController *)viewController {
  UIViewController *rootViewController =
      [UIApplication sharedApplication].delegate.window.rootViewController;
  [rootViewController presentViewController:viewController animated:YES completion:nil];
}

- (void)signIn:(GIDSignIn *)signIn dismissViewController:(UIViewController *)viewController {
  [viewController dismissViewControllerAnimated:YES completion:nil];
}

#pragma mark - <GIDSignInDelegate> protocol

- (void)signIn:(GIDSignIn *)signIn
    didSignInForUser:(GIDGoogleUser *)user
           withError:(NSError *)error {
  if (error != nil) {
    if (error.code == -4) {
      // Occurs when silent sign-in is not possible, return an empty user in this case
      [self respondWithAccount:nil error:nil];
    } else {
      [self respondWithAccount:nil error:error];
    }
  } else {
    NSURL *photoUrl;
    if (user.profile.hasImage) {
      // Placeholder that will be replaced by on the Dart side based on screen size
      photoUrl = [user.profile imageURLWithDimension:1337];
    }
    [self respondWithAccount:@{
      @"displayName" : user.profile.name ?: [NSNull null],
      @"email" : user.profile.email ?: [NSNull null],
      @"id" : user.userID ?: [NSNull null],
      @"photoUrl" : [photoUrl absoluteString] ?: [NSNull null],
    }
                       error:nil];
  }
}

- (void)signIn:(GIDSignIn *)signIn
    didDisconnectWithUser:(GIDGoogleUser *)user
                withError:(NSError *)error {
  [self respondWithAccount:@{} error:nil];
}

#pragma mark - private methods

- (void)respondWithAccount:(id)account error:(NSError *)error {
  NSArray<FlutterResult> *requests = _accountRequests;
  _accountRequests = [[NSMutableArray alloc] init];
  for (FlutterResult accountRequest in requests) {
    accountRequest(error != nil ? error.flutterError : account);
  }
}

@end