You can use Firebase Authentication to allow users to sign in to your app using one or more sign-in methods, including email address and password sign-in, and federated identity providers such as Google Sign-in and Facebook Login. This tutorial gets you started with Firebase Authentication by showing you how to add email address and password sign-in to your app.
Connect your app to Firebase
- Install the Firebase SDK.
- In the Firebase console, add your app to your Firebase project.
Add Firebase Authentication to your Xcode project
First, ensure the following dependencies are in your project's Podfile:
pod 'Firebase/Core'
pod 'Firebase/Auth'
Then, run pod install and open the created .xcworkspace file.
Initialize the Firebase SDK
In your app delegate, first import the Firebase SDK:
Swift
import Firebase
Objective-C
@import Firebase;
Then, in the application:didFinishLaunchingWithOptions: method, initialize the
FirebaseApp object:
Swift
// Use Firebase library to configure APIs
FirebaseApp.configure()
Objective-C
// Use Firebase library to configure APIs
[FIRApp configure];
Listen for authentication state
For each of your app's views that need information about the signed-in user,
attach a listener to the FIRAuth object. This listener gets called whenever
the user's sign-in state changes.
Attach the listener in the view controller's viewWillAppear method:
Swift
handle = Auth.auth().addStateDidChangeListener { (auth, user) in
// ...
}
Objective-C
self.handle = [[FIRAuth auth]
addAuthStateDidChangeListener:^(FIRAuth *_Nonnull auth, FIRUser *_Nullable user) {
// ...
}];
And detach the listener in the view controller's viewWillDisappear method:
Swift
Auth.auth().removeStateDidChangeListener(handle!)
Objective-C
[[FIRAuth auth] removeAuthStateDidChangeListener:_handle];
Sign up new users
Create a form that allows new users to register with your app using their email
address and a password. When a user completes the form, validate the email
address and password provided by the user, then pass them to the createUser
method:
Swift
Auth.auth().createUser(withEmail: email, password: password) { authResult, error in
// ...
}
Objective-C
[[FIRAuth auth] createUserWithEmail:email
password:password
completion:^(FIRAuthDataResult * _Nullable authResult,
NSError * _Nullable error) {
// ...
}];
Sign in existing users
Create a form that allows existing users to sign in using their email address
and password. When a user completes the form, call the signIn method:
Swift
Auth.auth().signIn(withEmail: email, password: password) { [weak self] user, error in
guard let strongSelf = self else { return }
// ...
}
Objective-C
[[FIRAuth auth] signInWithEmail:self->_emailField.text
password:self->_passwordField.text
completion:^(FIRAuthDataResult * _Nullable authResult,
NSError * _Nullable error) {
// ...
}];
Get user information
After a user signs in successfully, you can get information about the user. For example, in your authentication state listener:
Swift
if let user = user {
// 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 getTokenWithCompletion:completion: instead.
let uid = user.uid
let email = user.email
let photoURL = user.photoURL
// ...
}
Objective-C
if (user) {
// 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 getTokenWithCompletion:completion: instead.
NSString *uid = user.uid;
NSString *email = user.email;
NSURL *photoURL = user.photoURL;
// ...
}
Next steps
Learn how to add support for other identity providers and anonymous guest accounts:
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