FirebaseUI for iOS — Auth

FirebaseUI is an open-source library for iOS that provides simple, customizable UI bindings on top of Firebase SDKs to eliminate boilerplate code and promote best practices.

FirebaseUI provides a drop-in auth solution that handles the UI flows for signing in users with email addresses and passwords, Google Sign-In, and Facebook Login. It is built on top of Firebase Auth.

The FirebaseUI Auth component implement best practices for authentication on mobile devices and websites, which can maximize sign-in and sign-up conversion for your app. It also handles edge cases like account recovery and account linking that can be security sensitive and error-prone to handle correctly.

FirebaseUI can be easily customized to fit in with the rest of your app's visual style, and it is open source, so you aren't constrained in realizing the user experience you want.

Compatible FirebaseUI clients are also available for Android and Web.

Table of Contents

1. Installation
2. Usage instructions
3. Customization

Installation

Importing FirebaseUI components for auth

Add the following line to your Podfile:

pod 'FirebaseUI/Auth'

Configuring sign-in providers

To use FirebaseUI to authenticate users you first need to configure each provider you want to use in their own developer app settings. Please read the Before you begin section of the Firebase Auth guides at the following links: Email and password Google Facebook

Using FirebaseUI for Authentication

Configuration

All operations, callbacks, UI customizations are done through an FIRAuthUI instance. The FIRAuthUI instance associated with the default FIRAuth instance can be accessed as follows:

@import Firebase
@import FirebaseAuthUI
...
[FIRApp configure];
FIRAuthUI *authUI = [FIRAuthUI authUI];
authUI.delegate = self; // Set the delegate to receive callback.

This instance can then be configured with the providers you wish to support:

@import FirebaseGoogleAuthUI
@import FirebaseFacebookAuthUI
...
FIRGoogleAuthUI *googleAuthUI =
    [[FIRGoogleAuthUI alloc] initWithClientID:kGoogleClientID];
FIRFacebookAuthUI *facebookAuthUI =
    [[FIRFacebookAuthUI alloc] initWithAppID:kFacebookAppID];
authUI.providers = @[ googleAuthUI, facebookAuthUI];

For Google sign in support, add custom URL schemes to your Xcode project (step 1 of the implement Google Sign-In documentation).

For Facebook sign in support, follow step 3 and 4 of Facebook login documentation , and add custom URL schemes following step 5 of Facebook SDK for iOS-Getting started documentation.

Finally add a call to handle the URL that your application receives at the end of the Google/Facebook authentication process.

- (BOOL)application:(UIApplication *)application
            openURL:(NSURL *)url
  sourceApplication:(NSString *)sourceApplication
         annotation:(id)annotation {
  return [[FIRAuthUI authUI] handleOpenURL:url sourceApplication:sourceApplication]
}

Sign In

To start the authentication flow, obtain an authViewController instance from FIRAuthUI. In order to leverage FirebaseUI for iOS you must display the authViewController; you can present it as the first view controller of your app or present it from another view controller within your app. In order to present the authViewController obtain as instance as follows:

UIViewController *authViewController = [authUI authViewController];
// Use authViewController as your root view controller,
// or present it on top of an existing view controller.

- (void)authUI:(FIRAuthUI *)authUI
      didSignInWithUser:(nullable FIRUser *)user
                  error:(nullable NSError *)error {
  // Implement this method to handle signed in user or error if any.
}

Customizing FirebaseUI for authentication

Terms of Service (ToS) URL customization:

The Terms of Service URL for your application, which is displayed on the email/password account creation screen, can be specified as follows:

authUI.TOSURL = [NSURL URLWithString:@"http://example.com/tos"];

Custom strings

You can override the default messages and prompts shown to your users. This can be useful for things such as adding support for other languages besides English.

In order to do so:

authUI.customStringsBundle = [NSBundle mainBundle]; // Or any custom bundle.

The bundle should include .strings files that have the same names as the default files, namely FirebaseAuthUI, FirebaseGoogleAuthUI, and FirebaseFacebookAuthUI. Each string in these files should have the same key as its counterpart in the default .strings files.

Custom sign-in screen

You can customize everything about the authentication method picker screen, except for the actual sign-in buttons.

In order to do so, create a subclass of FIRAuthPickerViewController and customize it to your needs. Provide FIRAuthUI with an instance of your subclass by implementing the delegate method authPickerViewControllerForAuthUI: as follows:

- (FIRAuthPickerViewController *)authPickerViewControllerForAuthUI:(FIRAuthUI *)authUI {
  return [[YourCustomAuthPickerViewController alloc] initWithAuthUI:authUI];
}