feat(auth, android): Play Games provider sign-in support (#12201)

Co-authored-by: Mike Diarmid <[email protected]>

Author: russellwheatley

docs/auth/federated-auth.md

@@ -91,37 +91,29 @@ Ensure the "Google" sign-in provider is enabled on the [Firebase Console](https:
   }
   ```
 
-## Google Play Games {:#games}
+## Google Play Games (Android only) {:#games}
 
-You can authenticate users in your Android game using Play Games Sign-In.
+Ensure the "Play Games" sign-in provider is enabled on the [Firebase Console](https://console.firebase.google.com/project/_/authentication/providers).
+Follow these instructions for [Play Games Firebase project set-up](https://firebase.google.com/docs/auth/android/play-games#set-up-firebase-project).
 
-* {Android}
-
-  Follow the instructions for Google setup on Android, then configure
-  [Play Games services with your Firebase app information](https://firebase.google.com/docs/auth/android/play-games#configure-play-games-with-firebase-info).
-
-  The following will trigger the sign-in flow, create a new credential and sign in the user:
-
-  ```dart
-  final googleUser = await GoogleSignIn(
-    signInOption: SignInOption.games,
-  ).signIn();
-
-  final googleAuth = await googleUser?.authentication;
-
-  if (googleAuth != null) {
-    // Create a new credential
-    final credential = GoogleAuthProvider.credential(
-      accessToken: googleAuth.accessToken,
-      idToken: googleAuth.idToken,
-    );
-
-    // Once signed in, return the UserCredential
-    await _auth.signInWithCredential(credential);
-  }
-  ```
+Follow these [instructions for configuring Play Games services](https://firebase.google.com/docs/auth/android/play-games#configure-play-games-with-firebase-info)
+with your Firebase app.
 
+* {Android}
 
+```dart
+Future<void> _signInWithPlayGames() async {
+  // Get server auth code from 3rd party provider
+  // See PR description for details on how you might get the server auth code:
+  // https://github.com/firebase/flutterfire/pull/12201#issue-2100392487
+  final serverAuthCode = '...';
+  final playGamesCredential = PlayGamesAuthProvider.credential(
+                                          serverAuthCode: serverAuthCode);
+
+  await FirebaseAuth.instance
+    .signInWithCredential(playGamesCredential);
+}
+```
 
 ## Facebook
 

packages/firebase_auth/firebase_auth/android/src/main/java/io/flutter/plugins/firebase/auth/Constants.java

@@ -19,7 +19,7 @@ public class Constants {
   public static final String SIGN_IN_METHOD_GITHUB = "github.com";
   public static final String SIGN_IN_METHOD_PHONE = "phone";
   public static final String SIGN_IN_METHOD_OAUTH = "oauth";
-
+  public static final String SIGN_IN_METHOD_PLAY_GAMES = "playgames.google.com";
   // User
   public static final String USER = "user";
   public static final String EMAIL = "email";
@@ -37,6 +37,7 @@ public class Constants {
   public static final String SIGN_IN_METHOD = "signInMethod";
   public static final String FORCE_RESENDING_TOKEN = "forceResendingToken";
   public static final String NAME = "name";
+  public static final String SERVER_AUTH_CODE = "serverAuthCode";
 
   // MultiFactor
   public static final String MULTI_FACTOR_HINTS = "multiFactorHints";

packages/firebase_auth/firebase_auth/android/src/main/java/io/flutter/plugins/firebase/auth/PigeonParser.java

@@ -28,6 +28,7 @@
 import com.google.firebase.auth.OAuthProvider;
 import com.google.firebase.auth.PhoneAuthProvider;
 import com.google.firebase.auth.PhoneMultiFactorInfo;
+import com.google.firebase.auth.PlayGamesAuthProvider;
 import com.google.firebase.auth.TwitterAuthProvider;
 import com.google.firebase.auth.UserInfo;
 import java.util.ArrayList;
@@ -226,6 +227,12 @@ static AuthCredential getCredential(Map<String, Object> credentialMap) {
 
           return builder.build();
         }
+      case Constants.SIGN_IN_METHOD_PLAY_GAMES:
+        {
+          String serverAuthCode =
+              (String) Objects.requireNonNull(credentialMap.get(Constants.SERVER_AUTH_CODE));
+          return PlayGamesAuthProvider.getCredential(serverAuthCode);
+        }
       default:
         return null;
     }

packages/firebase_auth/firebase_auth/example/android/app/src/main/AndroidManifest.xml

@@ -10,6 +10,8 @@
     <meta-data
       android:name="com.facebook.sdk.ClientToken"
       android:value="@string/facebook_client_token" />
+    <meta-data android:name="com.google.android.gms.games.APP_ID"
+      android:value="@string/game_services_project_id"/>
     <activity
       android:name=".MainActivity"
       android:configChanges="orientation|keyboardHidden|keyboard|screenSize|smallestScreenSize|locale|layoutDirection|fontScale|screenLayout|density|uiMode"

packages/firebase_auth/firebase_auth/example/android/app/src/main/res/values/strings.xml

@@ -3,4 +3,7 @@
   <string name="facebook_app_id">128693022464535</string>
   <!--  The Facebook client token should not be made public but this is a developer mode app with whitelisted user access -->
   <string name="facebook_client_token">16dbbdf0cfb309034a6ad98ac2a21688</string>
+  <!-- Default web client id for Play games -->
+  <string name="default_web_client_id">406099696497-a12gakvts4epfk5pkio7dphc1anjiggc.apps.googleusercontent.com</string>
+  <string translatable="false"  name="game_services_project_id">406099696497</string>
 </resources>

packages/firebase_auth/firebase_auth/lib/firebase_auth.dart

@@ -39,6 +39,8 @@ export 'package:firebase_auth_platform_interface/firebase_auth_platform_interfac
         EmailAuthCredential,
         FacebookAuthProvider,
         FacebookAuthCredential,
+        PlayGamesAuthProvider,
+        PlayGamesAuthCredential,
         GithubAuthProvider,
         GithubAuthCredential,
         GoogleAuthProvider,

packages/firebase_auth/firebase_auth_platform_interface/lib/firebase_auth_platform_interface.dart

@@ -36,6 +36,7 @@ export 'src/providers/phone_auth.dart';
 export 'src/providers/saml_auth.dart';
 export 'src/providers/twitter_auth.dart';
 export 'src/providers/yahoo_auth.dart';
+export 'src/providers/play_games_auth.dart';
 export 'src/types.dart';
 export 'src/user_info.dart';
 export 'src/user_metadata.dart';

packages/firebase_auth/firebase_auth_platform_interface/lib/src/providers/oauth.dart

@@ -81,6 +81,7 @@ class OAuthCredential extends AuthCredential {
     this.idToken,
     this.secret,
     this.rawNonce,
+    this.serverAuthCode,
   }) : super(
           providerId: providerId,
           signInMethod: signInMethod,
@@ -100,6 +101,9 @@ class OAuthCredential extends AuthCredential {
   /// must match the nonce field in the ID token.
   final String? rawNonce;
 
+  /// the server auth code for Play Games credential.
+  final String? serverAuthCode;
+
   @override
   Map<String, String?> asMap() {
     return <String, String?>{
@@ -109,6 +113,7 @@ class OAuthCredential extends AuthCredential {
       'accessToken': accessToken,
       'secret': secret,
       'rawNonce': rawNonce,
+      'serverAuthCode': serverAuthCode,
     };
   }
 }

packages/firebase_auth/firebase_auth_platform_interface/lib/src/providers/play_games_auth.dart

@@ -0,0 +1,79 @@
+// Copyright 2024 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+import 'package:firebase_auth_platform_interface/firebase_auth_platform_interface.dart';
+
+const _kProviderId = 'playgames.google.com';
+
+/// This class should be used to either create a new Play Games credential with an
+/// access code, or use the provider to trigger user authentication flows.
+///
+/// If authenticating with Play Games via a 3rd party, use the returned
+/// `serverAuthCode` to sign-in or link the user with the created credential,
+/// for example:
+///
+/// ```dart
+/// String serverAuthCode = '...'; // From 3rd party provider
+/// var playGamesAuthCredential = PlayGamesAuthCredential.credential(serverAuthCode: serverAuthCode);
+///
+/// FirebaseAuth.instance.signInWithCredential(playGamesAuthCredential)
+///   .then(...);
+/// ```
+class PlayGamesAuthProvider extends AuthProvider {
+  /// Creates a new instance.
+  PlayGamesAuthProvider() : super(_kProviderId);
+
+  /// Create a new [PlayGamesAuthCredential] from a provided [serverAuthCode]
+  static OAuthCredential credential({
+    required String serverAuthCode,
+  }) {
+    return PlayGamesAuthCredential._credential(
+      serverAuthCode: serverAuthCode,
+    );
+  }
+
+  /// This corresponds to the sign-in method identifier.
+  static String get PLAY_GAMES_SIGN_IN_METHOD {
+    return _kProviderId;
+  }
+
+  // ignore: public_member_api_docs
+  static String get PROVIDER_ID {
+    return _kProviderId;
+  }
+
+  Map<String, String> _parameters = {};
+
+  /// Returns the parameters for this provider instance.
+  Map<String, String> get parameters {
+    return _parameters;
+  }
+
+  /// Sets the OAuth custom parameters to pass in a Play Games OAuth request for
+  /// popup and redirect sign-in operations.
+  PlayGamesAuthProvider setCustomParameters(
+    Map<String, String> customOAuthParameters,
+  ) {
+    _parameters = customOAuthParameters;
+    return this;
+  }
+}
+
+/// The auth credential returned from calling
+/// [PlayGamesAuthProvider.credential].
+class PlayGamesAuthCredential extends OAuthCredential {
+  PlayGamesAuthCredential._({
+    required String serverAuthCode,
+  }) : super(
+          providerId: _kProviderId,
+          signInMethod: _kProviderId,
+          serverAuthCode: serverAuthCode,
+        );
+
+  factory PlayGamesAuthCredential._credential({
+    required String serverAuthCode,
+  }) {
+    return PlayGamesAuthCredential._(serverAuthCode: serverAuthCode);
+  }
+}