Authenticate Using Google Sign-In and Unity

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

Before you begin

Before you can use the Firebase Authentication, you will need to create a Firebase project, and add the Firebase Unity SDK packages to your Unity project.

Setup:

Prerequisites

Android

iOS

  • Unity 5.0 or later
  • Xcode 8.0 or later

If you don't have a Unity project already, you can download one of our quickstart samples and experiment with a specific Firebase feature. If you're using a quickstart, remember to get the bundle identifier from the project settings; you need it for the next step.

Set up your app in the Firebase console

To add Firebase to your app, you need a Firebase project and a Firebase configuration file for your app.

To create a Firebase project:

  1. Go to the Firebase console.

  2. Click Add project, then select or enter a Project name.

    • If you have an existing Google project associated with your app, select the project from the Project name dropdown menu.
    • If you don't have an existing Google project, enter a new Project name.
  3. (Optional) Edit the Project ID.

    Firebase automatically assigns a unique ID to your Firebase project. This identifier displays in publicly visible Firebase services, for example:

    • Default database URL — your-project-id.firebaseio.com
    • Default hosting subdomain — your-project-id.firebaseapp.com
  4. Follow the remaining setup steps, then click Create project (or Add Firebase, if you're using an existing Google project).

Firebase automatically provisions resources for your Firebase project. The process typically takes a few minutes. When the process completes, you'll be taken to the overview page for your Firebase project in the Firebase console.

Android

  1. Click Add Firebase to your Android app and follow the setup steps. If you're importing an existing Google project, this may happen automatically and you can just download the config file.
  2. When prompted, enter your app's package name. It's important to enter the package name your app is using; this can only be set when you add an app to your Firebase project.
  3. During the process, you'll download a google-services.json file. You can download this file again at any time.
  4. After you add the initialization code, run your app to send verification to the Firebase console that you've successfully installed Firebase.

iOS

  1. Click Add Firebase to your iOS app and follow the setup steps. If you're importing an existing Google project, this may happen automatically and you can just download the config file.
  2. When prompted, enter your app's bundle ID. It's important to enter the bundle ID your app is using; this can only be set when you add an app to your Firebase project.
  3. During the process, you'll download a GoogleService-Info.plist file. You can download this file again at any time.
  4. After you add the initialization code, run your app to send verification to the Firebase console that you've successfully installed Firebase.
  5. Drag the GoogleService-Info.plist downloaded from the Firebase console into any folder in the Unity project.

Add the Firebase Unity SDK to your app

  1. Download the Firebase Unity SDK.
  2. Select the Assets > Import Package > Custom Package menu item.
  3. Import FirebaseAuth.unitypackage from the directory that matches the version of Unity you use:
    • Unity 5.x and earlier use the .NET 3.x framework, so you need to import the dotnet3/FirebaseAuth.unitypackage package.
    • Unity 2017.x and newer allow the use of the .NET 4.x framework. If your project is configured to use .NET 4.x, import the dotnet4/FirebaseAuth.unitypackage package.
  4. When the Import Unity Package window appears, click the Import button.

Initialize the SDK

The Firebase Unity SDK on Android requires Google Play services, which must be up-to-date before the SDK can be used. The following code should be added at the start of your application to check for and optionally update Google Play services to the version required by the Firebase Unity SDK before calling any other methods in the SDK.

Firebase.FirebaseApp.CheckAndFixDependenciesAsync().ContinueWith(task => {
  var dependencyStatus = task.Result;
  if (dependencyStatus == Firebase.DependencyStatus.Available) {
    // Create and hold a reference to your FirebaseApp, i.e.
    //   app = Firebase.FirebaseApp.DefaultInstance;
    // where app is a Firebase.FirebaseApp property of your application class.

    // Set a flag here indicating that Firebase is ready to use by your
    // application.
  } else {
    UnityEngine.Debug.LogError(System.String.Format(
      "Could not resolve all Firebase dependencies: {0}", dependencyStatus));
    // Firebase Unity SDK is not safe to use here.
  }
});

Build your app

Android

  1. Select the File > Build Settings menu option.
  2. Select Android in the Platform list.
  3. Click Switch Platform to select Android as the target platform.
  4. Wait for the spinner (compiling) icon in the bottom right corner of the Unity status bar to stop.
  5. Click Build and Run.

iOS

  1. Select the File > Build Settings menu option.
  2. Select iOS in the Platform list.
  3. Click Switch Platform to select iOS as the target platform.
  4. Wait for the spinner (compiling) icon in the bottom right corner of the Unity status bar to stop.
  5. Click Build and Run.

Access the Firebase.Auth.FirebaseAuth class

The FirebaseAuth class is the gateway for all API calls. It is accessable through FirebaseAuth.DefaultInstance.
Firebase.Auth.FirebaseAuth auth = Firebase.Auth.FirebaseAuth.DefaultInstance;

Authenticate with Firebase

  1. Follow instructions for Android and iOS to get an ID token for the Google sign in.
  2. After a user successfully signs in, exchange the access token for a Firebase credential, and authenticate with Firebase using the Firebase credential:
    Firebase.Auth.Credential credential =
        Firebase.Auth.GoogleAuthProvider.GetCredential(googleIdToken, googleAccessToken);
    auth.SignInWithCredentialAsync(credential).ContinueWith(task => {
      if (task.IsCanceled) {
        Debug.LogError("SignInWithCredentialAsync was canceled.");
        return;
      }
      if (task.IsFaulted) {
        Debug.LogError("SignInWithCredentialAsync encountered an error: " + task.Exception);
        return;
      }
    
      Firebase.Auth.FirebaseUser newUser = task.Result;
      Debug.LogFormat("User signed in successfully: {0} ({1})",
          newUser.DisplayName, newUser.UserId);
    });
    

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 Firebase.Auth.FirebaseUser object:

    Firebase.Auth.FirebaseUser user = auth.CurrentUser;
    if (user != null) {
      string name = user.DisplayName;
      string email = user.Email;
      System.Uri photo_url = user.PhotoUrl;
      // The user's Id, unique to the Firebase project.
      // Do NOT use this value to authenticate with your backend server, if you
      // have one; use User.TokenAsync() instead.
      string uid = user.UserId;
    }
    
  • 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():

auth.SignOut();

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