Gestisci utenti in Firebase

Create a user

You create a new user in your Firebase project by calling the createUserWithEmailAndPassword method or by signing in a user for the first time using a federated identity provider, such as Google Sign-In or Facebook Login.

You can also create new password-authenticated users from the Authentication section of the Firebase console, on the Users page.

Get the currently signed-in user

The recommended way to get the current user is by calling the getCurrentUser method. If no user is signed in, getCurrentUser returns null:

Java

FirebaseUser user = FirebaseAuth.getInstance().getCurrentUser();
if (user != null) {
    // User is signed in
} else {
    // No user is signed in
}MainActivity.java

Kotlin+KTX

val user = Firebase.auth.currentUser
if (user != null) {
    // User is signed in
} else {
    // No user is signed in
}MainActivity.kt

There are some cases where getCurrentUser will return a non-null FirebaseUser but the underlying token is not valid. This can happen, for example, if the user was deleted on another device and the local token has not refreshed. In this case, you may get a valid user getCurrentUser but subsequent calls to authenticated resources will fail.

getCurrentUser might also return null because the auth object has not finished initializing.

If you attach an AuthStateListener you will get a callback every time the underlying token state changes. This can be useful to react to edge cases like those mentioned above.

Get a user's profile

To get a user's profile information, use the accessor methods of an instance of FirebaseUser. For example:

Java

FirebaseUser user = FirebaseAuth.getInstance().getCurrentUser();
if (user != null) {
    // Name, email address, and profile photo Url
    String name = user.getDisplayName();
    String email = user.getEmail();
    Uri photoUrl = user.getPhotoUrl();

    // Check if user's email is verified
    boolean emailVerified = user.isEmailVerified();

    // 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
    // FirebaseUser.getIdToken() instead.
    String uid = user.getUid();
}MainActivity.java

Kotlin+KTX

val user = Firebase.auth.currentUser
user?.let {
    // Name, email address, and profile photo Url
    val name = user.displayName
    val email = user.email
    val photoUrl = user.photoUrl

    // Check if user's email is verified
    val emailVerified = user.isEmailVerified

    // 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
    // FirebaseUser.getToken() instead.
    val uid = user.uid
}MainActivity.kt

Get a user's provider-specific profile information

To get the profile information retrieved from the sign-in providers linked to a user, use the getProviderData method. For example:

Java

FirebaseUser user = FirebaseAuth.getInstance().getCurrentUser();
if (user != null) {
    for (UserInfo profile : user.getProviderData()) {
        // Id of the provider (ex: google.com)
        String providerId = profile.getProviderId();

        // UID specific to the provider
        String uid = profile.getUid();

        // Name, email address, and profile photo Url
        String name = profile.getDisplayName();
        String email = profile.getEmail();
        Uri photoUrl = profile.getPhotoUrl();
    }
}MainActivity.java

Kotlin+KTX

val user = Firebase.auth.currentUser
user?.let {
    for (profile in it.providerData) {
        // Id of the provider (ex: google.com)
        val providerId = profile.providerId

        // UID specific to the provider
        val uid = profile.uid

        // Name, email address, and profile photo Url
        val name = profile.displayName
        val email = profile.email
        val photoUrl = profile.photoUrl
    }
}MainActivity.kt

Update a user's profile

You can update a user's basic profile information—the user's display name and profile photo URL—with the updateProfile method. For example:

Java

FirebaseUser user = FirebaseAuth.getInstance().getCurrentUser();

UserProfileChangeRequest profileUpdates = new UserProfileChangeRequest.Builder()
        .setDisplayName("Jane Q. User")
        .setPhotoUri(Uri.parse("https://example.com/jane-q-user/profile.jpg"))
        .build();

user.updateProfile(profileUpdates)
        .addOnCompleteListener(new OnCompleteListener<Void>() {
            @Override
            public void onComplete(@NonNull Task<Void> task) {
                if (task.isSuccessful()) {
                    Log.d(TAG, "User profile updated.");
                }
            }
        });MainActivity.java

Kotlin+KTX

val user = Firebase.auth.currentUser

val profileUpdates = userProfileChangeRequest {
    displayName = "Jane Q. User"
    photoUri = Uri.parse("https://example.com/jane-q-user/profile.jpg")
}

user!!.updateProfile(profileUpdates)
        .addOnCompleteListener { task ->
            if (task.isSuccessful) {
                Log.d(TAG, "User profile updated.")
            }
        }MainActivity.kt

Set a user's email address

You can set a user's email address with the updateEmail method. For example:

Java

FirebaseUser user = FirebaseAuth.getInstance().getCurrentUser();

user.updateEmail("user@example.com")
        .addOnCompleteListener(new OnCompleteListener<Void>() {
            @Override
            public void onComplete(@NonNull Task<Void> task) {
                if (task.isSuccessful()) {
                    Log.d(TAG, "User email address updated.");
                }
            }
        });MainActivity.java

Kotlin+KTX

val user = Firebase.auth.currentUser

user!!.updateEmail("user@example.com")
        .addOnCompleteListener { task ->
            if (task.isSuccessful) {
                Log.d(TAG, "User email address updated.")
            }
        }MainActivity.kt

Send a user a verification email

You can send an address verification email to a user with the sendEmailVerification method. For example:

Java

FirebaseAuth auth = FirebaseAuth.getInstance();
FirebaseUser user = auth.getCurrentUser();

user.sendEmailVerification()
        .addOnCompleteListener(new OnCompleteListener<Void>() {
            @Override
            public void onComplete(@NonNull Task<Void> task) {
                if (task.isSuccessful()) {
                    Log.d(TAG, "Email sent.");
                }
            }
        });MainActivity.java

Kotlin+KTX

val user = Firebase.auth.currentUser

user!!.sendEmailVerification()
        .addOnCompleteListener { task ->
            if (task.isSuccessful) {
                Log.d(TAG, "Email sent.")
            }
        }MainActivity.kt

You can customize the email template that is used in Authentication section of the Firebase console, on the Email Templates page. See Email Templates in Firebase Help Center.

It is also possible to pass state via a continue URL to redirect back to the app when sending a verification email.

Additionally you can localize the verification email by updating the language code on the Auth instance before sending the email. For example:

Java

auth.setLanguageCode("fr");
// To apply the default app language instead of explicitly setting it.
// auth.useAppLanguage();MainActivity.java

Kotlin+KTX

auth.setLanguageCode("fr")
// To apply the default app language instead of explicitly setting it.
// auth.useAppLanguage()MainActivity.kt

Set a user's password

You can set a user's password with the updatePassword method. For example:

Java

FirebaseUser user = FirebaseAuth.getInstance().getCurrentUser();
String newPassword = "SOME-SECURE-PASSWORD";

user.updatePassword(newPassword)
        .addOnCompleteListener(new OnCompleteListener<Void>() {
            @Override
            public void onComplete(@NonNull Task<Void> task) {
                if (task.isSuccessful()) {
                    Log.d(TAG, "User password updated.");
                }
            }
        });MainActivity.java

Kotlin+KTX

val user = Firebase.auth.currentUser
val newPassword = "SOME-SECURE-PASSWORD"

user!!.updatePassword(newPassword)
        .addOnCompleteListener { task ->
            if (task.isSuccessful) {
                Log.d(TAG, "User password updated.")
            }
        }MainActivity.kt

Send a password reset email

You can send a password reset email to a user with the sendPasswordResetEmail method. For example:

Java

FirebaseAuth auth = FirebaseAuth.getInstance();
String emailAddress = "user@example.com";

auth.sendPasswordResetEmail(emailAddress)
        .addOnCompleteListener(new OnCompleteListener<Void>() {
            @Override
            public void onComplete(@NonNull Task<Void> task) {
                if (task.isSuccessful()) {
                    Log.d(TAG, "Email sent.");
                }
            }
        });MainActivity.java

Kotlin+KTX

val emailAddress = "user@example.com"

Firebase.auth.sendPasswordResetEmail(emailAddress)
        .addOnCompleteListener { task ->
            if (task.isSuccessful) {
                Log.d(TAG, "Email sent.")
            }
        }MainActivity.kt

You can customize the email template that is used in Authentication section of the Firebase console, on the Email Templates page. See Email Templates in Firebase Help Center.

It is also possible to pass state via a continue URL to redirect back to the app when sending a password reset email.

Additionally you can localize the password reset email by updating the language code on the Auth instance before sending the email. For example:

Java

auth.setLanguageCode("fr");
// To apply the default app language instead of explicitly setting it.
// auth.useAppLanguage();MainActivity.java

Kotlin+KTX

auth.setLanguageCode("fr")
// To apply the default app language instead of explicitly setting it.
// auth.useAppLanguage()MainActivity.kt

You can also send password reset emails from the Firebase console.

Delete a user

You can delete a user account with the delete method. For example:

Java

FirebaseUser user = FirebaseAuth.getInstance().getCurrentUser();

user.delete()
        .addOnCompleteListener(new OnCompleteListener<Void>() {
            @Override
            public void onComplete(@NonNull Task<Void> task) {
                if (task.isSuccessful()) {
                    Log.d(TAG, "User account deleted.");
                }
            }
        });MainActivity.java

Kotlin+KTX

val user = Firebase.auth.currentUser!!

user.delete()
        .addOnCompleteListener { task ->
            if (task.isSuccessful) {
                Log.d(TAG, "User account deleted.")
            }
        }MainActivity.kt

You can also delete users from the Authentication section of the Firebase console, on the Users page.

Re-authenticate a user

Some security-sensitive actions—such as deleting an account, setting a primary email address, and changing a password—require that the user has recently signed in. If you perform one of these actions, and the user signed in too long ago, the action fails and throws FirebaseAuthRecentLoginRequiredException. When this happens, re-authenticate the user by getting new sign-in credentials from the user and passing the credentials to reauthenticate. For example:

Java

FirebaseUser user = FirebaseAuth.getInstance().getCurrentUser();

// Get auth credentials from the user for re-authentication. The example below shows
// email and password credentials but there are multiple possible providers,
// such as GoogleAuthProvider or FacebookAuthProvider.
AuthCredential credential = EmailAuthProvider
        .getCredential("user@example.com", "password1234");

// Prompt the user to re-provide their sign-in credentials
user.reauthenticate(credential)
        .addOnCompleteListener(new OnCompleteListener<Void>() {
            @Override
            public void onComplete(@NonNull Task<Void> task) {
                Log.d(TAG, "User re-authenticated.");
            }
        });MainActivity.java

Kotlin+KTX

val user = Firebase.auth.currentUser!!

// Get auth credentials from the user for re-authentication. The example below shows
// email and password credentials but there are multiple possible providers,
// such as GoogleAuthProvider or FacebookAuthProvider.
val credential = EmailAuthProvider
        .getCredential("user@example.com", "password1234")

// Prompt the user to re-provide their sign-in credentials
user.reauthenticate(credential)
        .addOnCompleteListener { Log.d(TAG, "User re-authenticated.") }MainActivity.kt

Import user accounts

You can import user accounts from a file into your Firebase project by using the Firebase CLI's auth:import command. For example:

firebase auth:import users.json --hash-algo=scrypt --rounds=8 --mem-cost=14