You can use Firebase Authentication to create and use temporary anonymous accounts
to authenticate with Firebase. These temporary anonymous accounts can be used to
allow users who haven't yet signed up to your app to work with data protected
by security rules. If an anonymous user decides to sign up to your app, you can
link their sign-in credentials to the anonymous
account
so that they can continue to work with their protected data in
future sessions.
Before you begin
-
Use Swift Package Manager to install and manage Firebase dependencies.
- In Xcode, with your app project open, navigate to
File > Add Packages
.
- When prompted, add the Firebase Apple platforms SDK repository:
https://github.com/firebase/firebase-ios-sdk.git
- Choose the Firebase Authentication library.
- Add the
-ObjC
flag to the
Other Linker Flags
section of your target's build settings.
-
When finished, Xcode will automatically begin resolving and downloading your
dependencies in the background.
- If you haven't yet connected your app to your Firebase project, do so from
the
Firebase console
.
- Enable anonymous auth:
- In the
Firebase console
, open the
Auth
section.
- On the
Sign-in Methods
page, enable the
Anonymous
sign-in method.
- Optional
: If you've upgraded your project to
Firebase Authentication with Identity Platform
, you can enable automatic clean-up. When
you enable this setting, anonymous accounts older than 30 days will be automatically
deleted. In projects with automatic clean-up enabled, anonymous authentication will no
longer count toward usage limits or billing quotas. See
Automatic clean-up
.
Authenticate with Firebase anonymously
When a signed-out user uses an app feature that requires authentication with
Firebase, sign in the user anonymously by completing the following steps:
- Import the
FirebaseCore
module in your
UIApplicationDelegate
, as well as any other
Firebase modules
your app delegate uses.
For example, to use Cloud Firestore and Authentication:
SwiftUI
import SwiftUI
import FirebaseCore
import FirebaseFirestore
import FirebaseAuth
// ...
Swift
import FirebaseCore
import FirebaseFirestore
import FirebaseAuth
// ...
Objective-C
@import FirebaseCore;
@import FirebaseFirestore;
@import FirebaseAuth;
// ...
- Configure a
FirebaseApp
shared instance in your app delegate's
application(_:didFinishLaunchingWithOptions:)
method:
SwiftUI
// Use Firebase library to configure APIs
FirebaseApp.configure()
Swift
// Use Firebase library to configure APIs
FirebaseApp.configure()
Objective-C
// Use Firebase library to configure APIs
[FIRApp configure];
- If you're using SwiftUI, you must create an application delegate and attach it
to your
App
struct via
UIApplicationDelegateAdaptor
or
NSApplicationDelegateAdaptor
. You must also disable app delegate swizzling. For
more information, see the
SwiftUI instructions
.
SwiftUI
@main
struct YourApp: App {
// register app delegate for Firebase setup
@UIApplicationDelegateAdaptor(AppDelegate.self) var delegate
var body: some Scene {
WindowGroup {
NavigationView {
ContentView()
}
}
}
}
- Call the
signInAnonymouslyWithCompletion:
method:
Swift
Auth.auth().signInAnonymously { authResult, error in
// ...
}
Objective-C
[[FIRAuth auth] signInAnonymouslyWithCompletion:^(FIRAuthDataResult * _Nullable authResult,
NSError * _Nullable error) {
// ...
}];
- If the
signInAnonymouslyWithCompletion:
method completes
without error, you can get the anonymous user's account data from the
FIRAuthDataResult
object:
Swift
guard let user = authResult?.user else { return }
let isAnonymous = user.isAnonymous // true
let uid = user.uid
Objective-C
FIRUser *user = authResult.user;
BOOL isAnonymous = user.anonymous; // YES
NSString *uid = user.uid;
Convert an anonymous account to a permanent account
When an anonymous user signs up to your app, you might want to allow them to
continue their work with their new account—for example, you might want to
make the items the user added to their shopping cart before they signed up
available in their new account's shopping cart. To do so, complete the following
steps:
- When the user signs up, complete the sign-in flow for the user's
authentication provider up to, but not including, calling one of the
FIRAuth.signInWith
methods. For example, get the user's Google ID token,
Facebook access token, or email address and password.
Get an
FIRAuthCredential
for the new authentication provider:
Google Sign-In
Swift
guard
let authentication = user?.authentication,
let idToken = authentication.idToken
else {
return
}
let credential = GoogleAuthProvider.credential(withIDToken: idToken,
accessToken: authentication.accessToken)
Objective-C
FIRAuthCredential *credential =
[FIRGoogleAuthProvider credentialWithIDToken:result.user.idToken.tokenString
accessToken:result.user.accessToken.tokenString];
Facebook Login
Swift
let credential = FacebookAuthProvider
.credential(withAccessToken: AccessToken.current!.tokenString)
Objective-C
FIRAuthCredential *credential = [FIRFacebookAuthProvider
credentialWithAccessToken:[FBSDKAccessToken currentAccessToken].tokenString];
Email-password sign-in
Swift
let credential = EmailAuthProvider.credential(withEmail: email, password: password)
Objective-C
FIRAuthCredential *credential =
[FIREmailAuthProvider credentialWithEmail:email
password:password];
Pass the
FIRAuthCredential
object to the sign-in user's
linkWithCredential:completion:
method:
Swift
user.link(with: credential) { authResult, error in
// ...
}
}
Objective-C
[[FIRAuth auth].currentUser linkWithCredential:credential
completion:^(FIRAuthDataResult *result, NSError *_Nullable error) {
// ...
}];
If the call to
linkWithCredential:completion:
succeeds, the user's new account can
access the anonymous account's Firebase data.
Automatic clean-up
If you've upgraded your project to
Firebase Authentication with Identity Platform
, you can
enable automatic clean-up in the Firebase console. When you enable this feature you allow
Firebase to automatically delete anonymous accounts older than 30 days. In projects with automatic
clean-up enabled, anonymous authentication will not count toward usage limits or billing quotas.
- Any anonymous accounts created after enabling automatic clean-up might be automatically
deleted any time after 30 days post-creation.
- Existing anonymous accounts will be eligible for automatic deletion 30 days after
enabling automatic clean-up.
- If you turn automatic clean-up off, any anonymous accounts scheduled to be deleted will remain
scheduled to be deleted.
- If you "upgrade" an anonymous account by linking it to any sign-in method, the account will
not get automatically deleted.
If you want to see how many users will be affected before you enable this feature, and you've
upgraded your project to
Firebase Authentication with Identity Platform
, you can filter by
is_anon
in
Cloud
Logging
.
Next steps
Now that users can authenticate with Firebase, you can control their access to
data in your Firebase database using
Firebase rules
.