Setup

Serverpod comes with built-in user management and authentication. It is possible to build a custom authentication implementation, but the recommended way to authenticate users is to use the serverpod_auth module. The module makes it easy to authenticate with email or social sign-ins and currently supports signing in with email, Google, Apple, and Firebase.

Future versions of the authentication module will include more options. If you write another authentication module, please consider contributing your code.

Installing the auth module

Serverpod's auth module makes it easy to authenticate users through email or 3rd parties. The authentication module also handles basic user information, such as user names and profile pictures. Make sure to use the same version numbers as for Serverpod itself for all dependencies.

Server setup

Add the module as a dependency to the server project's pubspec.yaml.

$ dart pub add serverpod_auth_server

Add the authentication handler to the Serverpod instance.

import 'package:serverpod_auth_server/serverpod_auth_server.dart' as auth;

void run(List<String> args) async {
  var pod = Serverpod(
    args,
    Protocol(),
    Endpoints(),
    authenticationHandler: auth.authenticationHandler, // Add this line
  );

  ...
}

Optionally, add a nickname for the module in the config/generator.yaml file. This nickname will be used as the name of the module in the code.

modules:
  serverpod_auth:
    nickname: auth

While still in the server project, generate the client code and endpoint methods for the auth module by running the serverpod generate command line tool.

$ serverpod generate

Initialize the auth database

After adding the module to the server project, you need to initialize the database. First you have to create a new migration that includes the auth module tables. This is done by running the serverpod create-migration command line tool in the server project.

$ serverpod create-migration

Start your database container from the server project.

$ docker-compose up --build --detach

Then apply the migration by starting the server with the apply-migrations flag.

$ dart run bin/main.dart --role maintenance --apply-migrations

The full migration instructions can be found in the migration guide.

Configure Authentication

Serverpod's auth module comes with a default Authentication Configuration. To customize it, go to your main server.dart file, import the serverpod_auth_server module and set up the authentication configuration:

import 'package:serverpod_auth_server/module.dart' as auth;  
  
void run(List<String> args) async {

  auth.AuthConfig.set(auth.AuthConfig(  
    minPasswordLength: 12,
  ));  
    
  // Start the Serverpod server.  
  await pod.start();
}

Property	Description	Default
allowUnsecureRandom	True if unsecure random number generation is allowed. If set to false, an error will be thrown if the platform does not support secure random number generation.	false
emailSignInFailureResetTime	The reset period for email sign in attempts. Defaults to 5 minutes.	5min
enableUserImages	True if user images are enabled.	true
extraSaltyHash	True if the server should use the accounts email address as part of the salt when storing password hashes (strongly recommended).	true
firebaseServiceAccountKeyJson	Firebase service account key JSON file. Generate and download from the Firebase console.	-
importUserImagesFromGoogleSignIn	True if user images should be imported when signing in with Google.	true
legacyUserSignOutBehavior	Defines the default behavior for the deprecated signOut method used in the status endpoint. This setting controls whether users are signed out from all active devices (SignOutOption.allDevices) or just the current device (SignOutOption.currentDevice).	SignOutOption.allDevices
maxAllowedEmailSignInAttempts	Max allowed failed email sign in attempts within the reset period.	5
maxPasswordLength	The maximum length of passwords when signing up with email.	128
minPasswordLength	The minimum length of passwords when signing up with email.	8
onUserCreated	Called after a user has been created. Listen to this callback if you need to do additional setup.	-
onUserUpdated	Called whenever a user has been updated. This can be when the user name is changed or if the user uploads a new profile picture.	-
onUserWillBeCreated	Called when a user is about to be created, gives a chance to abort the creation by returning false.	-
passwordResetExpirationTime	The time for password resets to be valid.	24h
sendPasswordResetEmail	Called when a user should be sent a reset code by email.	-
sendValidationEmail	Called when a user should be sent a validation code on account setup.	-
userCanEditFullName	True if users can edit their full name.	false
userCanEditUserImage	True if users can update their profile images.	true
userCanEditUserName	True if users can edit their user names.	true
userCanSeeFullName	True if users can view their full name.	true
userCanSeeUserName	True if users can view their user name.	true
userImageFormat	The format used to store user images.	jpg
userImageGenerator	Generator used to produce default user images.	-
userImageQuality	The quality setting for images if JPG format is used.	70
userImageSize	The size of user images.	256
userInfoCacheLifetime	The duration which user infos are cached locally in the server.	1min
validationCodeLength	The length of the validation code used in the authentication process. This value determines the number of digits in the validation code. Setting this value to less than 3 reduces security.	8

Client setup

Add the auth client in your client project's pubspec.yaml.

dependencies:
  ...
  serverpod_auth_client: ^1.x.x

App setup

First, add dependencies to your app's pubspec.yaml file for the methods of signing in that you want to support.

dependencies:
  flutter:
    sdk: flutter
  serverpod_flutter: ^1.x.x
  auth_example_client:
    path: ../auth_example_client
  
  serverpod_auth_shared_flutter: ^1.x.x

Next, you need to set up a SessionManager, which keeps track of the user's state. It will also handle the authentication keys passed to the client from the server, upload user profile images, etc.

late SessionManager sessionManager;
late Client client;

void main() async {
  // Need to call this as we are using Flutter bindings before runApp is called.
  WidgetsFlutterBinding.ensureInitialized();

  // The android emulator does not have access to the localhost of the machine.
  // const ipAddress = '10.0.2.2'; // Android emulator ip for the host

  // On a real device replace the ipAddress with the IP address of your computer.
  const ipAddress = 'localhost';

  // Sets up a singleton client object that can be used to talk to the server from
  // anywhere in our app. The client is generated from your server code.
  // The client is set up to connect to a Serverpod running on a local server on
  // the default port. You will need to modify this to connect to staging or
  // production servers.
  client = Client(
    'http://$ipAddress:8080/',
    authenticationKeyManager: FlutterAuthenticationKeyManager(),
  )..connectivityMonitor = FlutterConnectivityMonitor();

  // The session manager keeps track of the signed-in state of the user. You
  // can query it to see if the user is currently signed in and get information
  // about the user.
  sessionManager = SessionManager(
    caller: client.modules.auth,
  );
  await sessionManager.initialize();

  runApp(MyApp());
}

The SessionManager has useful methods for viewing and monitoring the user's current state.

Check authentication state

To check if the user is signed in:

sessionManager.isSignedIn;

Returns true if the user is signed in, or false otherwise.

Access current user

To retrieve information about the current user:

sessionManager.signedInUser;

Returns a UserInfo object if the user is currently signed in, or null if the user is not.

Register authentication

To register a signed in user in the session manager:

await sessionManager.registerSignedInUser(
  userInfo,
  keyId,
  authKey,
);

This will persist the user information and refresh any open streaming connection, see Custom Providers - Client Setup for more details.

Monitor authentication changes

To add a listener that tracks changes in the user's authentication state, useful for updating the UI:

@override
void initState() {
  super.initState();
  
  // Rebuild the page if authentication state changes.
  sessionManager.addListener(() {
    setState(() {});
  });
}

The listener is triggered whenever the user's sign-in state changes.

Sign out current device

To sign the user out on from the current device:

await sessionManager.signOutDevice();

Returns true if the sign-out is successful, or false if it fails.

Sign out all devices

To sign the user out across all devices:

await sessionManager.signOutAllDevices();

Returns true if the user is successfully signed out from all devices, or false if it fails.

info

The signOut method is deprecated. This method calls the deprecated signOut status endpoint. For additional details, see the deprecated signout endpoint section. Use signOutDevice or signOutAllDevices instead.

await sessionManager.signOut();  // Deprecated