Auth - Provider - Google Identity

You can let your users authenticate with Firebase using their Google Accounts by integrating Google Sign-In into your app.

Before you begin

• Ensure you have setup Firebase in your application
• Enable Google Sign-In in the Firebase console:
  • In the Firebase console, open the Auth section.
  • On the Sign in method tab, enable the Google sign-in method and click Save.

Authenticate with Google

In order to sign in using Google accounts you will need to integrate Google Sign-In. You can do this using the Google Identity extension. The following guide uses this ANE however you can use any method you currently have to attain the id token.

Firstly, integrate Google Sign-In in your application by following the steps outlined in the Google Identity ANE.

You must ensure that you request the id token when setting up the extension, by setting requestIdToken to true:

var options:GoogleIdentityOptions = new GoogleIdentityOptionsBuilder()
    .requestIdToken()
    .setIOSClientID( Config.clientID_iOS )
    .setServerClientID( Config.serverClientID )
    .build();

GoogleIdentity.service.setup( options );

Then call sign in to authenticate your user using their Google account:

GoogleIdentity.service.addEventListener( GoogleIdentityEvent.SIGN_IN, googleIdentity_signInHandler );
                    
GoogleIdentity.service.signIn();

Authenticate with Firebase

When sign in completes you'll have access to the id token and access token. You use these to construct an AuthCredential that you can pass to the FirebaseAuth signInWithCredential function.

To create an AuthCredential for Google use the GoogleAuthProvider.getCredential method:

var credential:AuthCredential = GoogleAuthProvider.getCredential( idToken, accessToken );

Then pass this to signInWithCredential:

FirebaseAuth.service.signInWithCredential( credential );

The signInWithCredential method will return the FirebaseAuthEvent.SIGNIN_WITH_CREDENTIAL_COMPLETE event.

For example on the GoogleIdentityEvent.SIGN_IN event handler:

function googleIdentity_signInHandler( event:GoogleIdentityEvent ):void
{
    // Have google sign in, lets use this to sign into Firebase
    var idToken:String = event.user.authentication.idToken;
    var accessToken:String = event.user.authentication.accessToken; // probably will be null

    // Create AuthCredential    
    var credential:AuthCredential = GoogleAuthProvider.getCredential( idToken, accessToken );
    
    // Start sign-in to Firebase
    FirebaseAuth.service.addEventListener( FirebaseAuthEvent.SIGNIN_WITH_CREDENTIAL_COMPLETE, signInWithCredential_completeHandler );
    FirebaseAuth.service.signInWithCredential( credential );
}

You can then use the SIGNIN_WITH_CREDENTIAL_COMPLETE event to process the success sign-in which will have the FirebaseUser with a linked Google provider.

Next steps

After a user signs in for the first time, a new user account is created and linked to the credentials—that is, the user name and password, phone number, or auth provider information—the user signed in with. This new account is stored as part of your Firebase project, and can be used to identify a user across every app in your project, regardless of how the user signs in.

In your apps, you can get the user's basic profile information from the FirebaseUser object. In your Firebase Realtime Database and Cloud Storage Security Rules, you can get the signed-in user's unique user ID from the auth variable, and use it to control what data a user can access. You can allow users to sign in to your app using multiple authentication providers by linking auth provider credentials to an existing user account.

To sign out a user, call signOut:

FirebaseAuth.service.signOut();