descope 0.9.9

A Flutter package for working with the Descope API.

Descope for Flutter

The Descope package for flutter provides convenient access to the Descope user management and authentication APIs for applications written for Flutter. You can read more on the Descope Website.

Features

• Quickstart
• Session Management
• Custom Claims
• Error handling
• Running Flows
• Authenticate users using the authentication methods that suit your needs:
  • OTP (one-time password)
  • TOTP (timed one-time password / authenticator app)
  • Magic Link
  • Enchanted Link
  • OAuth (social)
  • SSO / SAML
  • Passkeys
  • Passwords

Quickstart

A Descope Project ID is required to initialize the SDK. Find it on the project page in the Descope Console.

import 'package:descope/descope.dart';

// Where your application state is being created
Descope.setup('<Your-Project-ID>');

// Optionally, you can configure the SDK to your needs
Descope.setup('<Your-Project-Id>', (config) {
  // set a custom base URL (needs to be set up in the Descope console)
  config.baseUrl = 'https://my.app.com';
  // enable the logger
  if (kDebugMode) {
    config.logger = DescopeLogger();
  }
});

// Load any available sessions
await Descope.sessionManager.loadSession();

Authenticate the user in your application by starting one of the authentication methods. For example, let's use OTP via email:

// sends an OTP code to the given email address
await Descope.otp.signUp(method: DeliveryMethod.email, loginId: '[e-mail]');

Finish the authentication by verifying the OTP code the user entered:

// if the user entered the right code the authentication is successful
final authResponse = await Descope.otp.verify(method: DeliveryMethod.email, loginId: '[e-mail]', code: code);

// we create a DescopeSession object that represents an authenticated user session
final session = DescopeSession.fromAuthenticationResponse(authResponse);

// the session manager automatically takes care of persisting the session
// and refreshing it as needed
Descope.sessionManager.manageSession(session);

On the next application launch check if there's a logged in user to decide which screen to show:

// check if we have a valid session from a previous launch and that it hasn't expired yet
if (Descope.sessionManager.session?.refreshToken?.isExpired == true) {
    // Show main UI
} else {
    // Show login UI
}

Use the active session to authenticate outgoing API requests to the application's backend:

request.setAuthorization(Descope.sessionManager);

Session Management

The DescopeSessionManager class is used to manage an authenticated user session for an application.

The session manager takes care of loading and saving the session as well as ensuring that it's refreshed when needed. When the user completes a sign in flow successfully you should set the DescopeSession object as the active session of the session manager.

final authResponse = await Descope.otp.verify(method: DeliverMethod.Email, loginId: '[e-mail]', code: '123456');
final session = DescopeSession.fromAuthenticationResponse(authResponse);
Descope.sessionManager.manageSession(session);

The session manager can then be used at any time to ensure the session is valid and to authenticate outgoing requests to your backend with a bearer token authorization header.

request.setAuthorization(Descope.sessionManager);

If your backend uses a different authorization mechanism you can of course use the session JWT directly instead of the extension function. You can either add another extension function on http.Request such as the one above, or you can do the following.

await Descope.sessionManager.refreshSessionIfNeeded();
final sessionJwt = Descope.sessionManager.session?.sessionJwt;
if (sessionJwt != null) {
    request.headers['X-Auth-Token'] = sessionJwt;
} else {
    // unauthorized
}

When the application is relaunched the DescopeSessionManager can load the existing session and you can check straight away if there's an authenticated user.

await Descope.sessionManager.loadSession();

If you prefer to call loadSession in your main() function, before the platform's runApp() function is called, then you'll need to ensure the widget bindings are initialized first:

void main() async {
  WidgetsFlutterBinding.ensureInitialized();

  Descope.setup('...');
  await Descope.sessionManager.loadSession();

  final session = Descope.sessionManager.session;
  if (session != null) {
    print('User is logged in: ${session.user}');
  }

  runApp(
    ...
  );
}

When the user wants to sign out of the application we revoke the active session and clear it from the session manager:

final refreshJwt = Descope.sessionManager.session?.refreshToken.jwt;
if (refreshJwt != null) {
  Descope.sessionManager.clearSession();
  try {
    Descope.auth.revokeSessions(RevokeType.currentSession, refreshJwt);
  } catch (e) {
    // handle errors
  }
}

It is also possible to revoke all sessions by providing the appropriate RevokeType parameter.

You can customize how the DescopeSessionManager behaves by using your own storage and lifecycle objects. See the documentation for more details.

Custom Claims

You can request for a sign in operation to add additional custom claims to the user's JWT during authentication.

For example, the following code starts an OTP sign in and requests a custom claim with the authenticated user's full name:

const options = SignInOptions(customClaims: {'name': '{{user.name}}'});
await Descope.otp.signIn(method: DeliveryMethod.email, loginId: '[e-mail]', options: options);

Note that any custom claims added via this method are considered insecure and will be nested under the nsec custom claim.

Error Handling

All authentication operations throw a DescopeException in case of a failure. There are several ways to catch and handle a DescopeException, and you can use whichever one is more appropriate in each specific use case.

try {
  final authResponse = await Descope.otp.verify(method: DeliveryMethod.email, loginId: loginId, code: code);
  final session = DescopeSession.fromAuthenticationResponse(authResponse);
  Descope.sessionManager.manageSession(session);
} on DescopeException catch (e) {
  switch(e) {
    case DescopeException.wrongOTPCode:
    case DescopeException.invalidRequest:
      showBadCodeAlert();
      break;
    case DescopeException.networkError:
      showNetworkErrorRetry();
      break;
    default:
      showUnexpectedErrorAlert(with: e);
  }
}

See the DescopeException class for specific error values. Note that not all API errors are listed in the SDK yet. Please let us know via a Github issue or pull request if you need us to add any entries to make your code simpler.

Running Flows

Important Note: DescopeFlowView is only available on iOS and Android platforms. Other platforms can still use the previous implementation of flows until DescopeFlowView is supported.

We can authenticate users by building and running Flows. Flows are built in the Descope flow editor. The editor allows you to easily define both the behavior and the UI that take the user through their authentication journey. Read more about it in the Descope getting started guide.

The flow setup differs according to the targeted platforms

Setup #1: Define and host your flow

Before we can run a mobile flow, it must first be defined and hosted. Every project comes with predefined flows out of the box. You can customize your flows to suit your needs and host it. Follow the getting started guide for more details. You can host the flow yourself or leverage Descope's hosted flow page. Read more about it here. You can also check out the auth-hosting repo itself.

(OPTIONAL) Setup #2.1: Enable App Links for Magic Link and OAuth (social) on Android

Some authentication methods rely on leaving the application's context to authenticate the user, such as navigating to an identity provider's website to perform OAuth (social) authentication, or receiving a Magic Link via email or text message. If you do not intend to use these authentication methods, you can skip this step. Otherwise, in order for the user to get back to your application, setting up App Links is required. Once you have a domain set up and verified for sending App Links, you'll need to handle the incoming deep links in your app, and resume the flow.

(OPTIONAL) Setup #2.2: Support Magic Link Redirects on iOS

Supporting Magic Link authentication in flows requires some platform specific setup: You'll need to support associated domains. It is recommended to follow the Flutter guide to deep linking for the basic setup or use an equivalent library.

Regardless of the platform, another path is required to handle magic link redirects specifically. For the sake of this README, let's name it /magiclink. It is possible to set up multiple paths if needed, in exactly the same way.

Provide a controller when setting up the DescopeFlowView

The DescopeFlowController is used to mainly use to call functions on the flow view, namely the resumeFromDeepLink function to resume a flow after returning from a magic link or social authentication. All app architectures are different, so it's up to you to decide where to store the controller. Here's a simple example of storing it in the app's state:

class AppModel extends ChangeNotifier {
  final DescopeFlowController _descopeFlowController = DescopeFlowController();

  DescopeFlowController get descopeFlowController => _descopeFlowController;

  void handleFlowDeepLink(Uri uri) {
    _descopeFlowController.resumeFromDeepLink(uri);
  }
}

Define a route to handle the App Link sent at the end of a flow

this code example demonstrates how app links should be handled - you can customize it to fit your app

// There are various way to listen for deep links in Flutter. This example does not assume any specific
// routing package, and focuses on the deep link handling itself.
final _handleIncomingLinks = (Uri uri) {
  if (uri.path == '/magiclink' || uri.path == '/oauth') { // This path needs to correspond to the deep link you configured in your manifest or associated domain - see below
    try {
      model.handleFlowDeepLink(uri);
    } catch (e) {
      // Handle errors here
    }
  }
};

Setup #3: Validate everything works

If deep links are required for your flows, it is recommended to validate that deep linking has been set up correctly. You can do that by running the app on a real device, and sending an app link to, for example, your email address. Clicking the link should open the app. If it does not, please review your setup and try again.

Run a Flow

After completing the prerequisite steps, it is now possible to run a flow. The flow will run in a dedicated DescopeFlowView widget which receives:

• DescopeFlowConfiguration - defines all of the options available when running a flow on both Android and iOS. Read the class documentation for a detailed explanation.
• DescopeFlowCallbacks - the callbacks or the main method the flow communicates with the hosting app. handle ready, success and error events as makes sense for your app.
• DescopeFlowController - used to control the flow view, mainly resuming from deep links. If no deep links are expected, this can be omitted.

All of these classes have detailed documentation. It is recommended to read them for a deeper understanding of how to use them.

There are truly many ways to integrate the flow view into your app. Here's a very simple example of a screen containing a DescopeFlowView with minimal configuration:

class _NativeFlowScreenState extends State<NativeFlowScreen> {
  bool _loading = true;

  @override
  Widget build(BuildContext context) {
    final bg = Theme.of(context).colorScheme.surface;
    return Scaffold(
      backgroundColor: bg,
      appBar: AppBar(
        backgroundColor: Theme.of(context).colorScheme.inversePrimary,
        title: const Text('Descope Flow View Example'),
        leading: IconButton(
          icon: const Icon(Icons.close),
          onPressed: () => context.pop(),
          tooltip: 'Close',
        ),
      ),
      body: SafeArea(
        child: Stack(
          children: [
            // Solid background to avoid black flash
            Positioned.fill(child: ColoredBox(color: bg)),
            // Keep the platform view mounted but invisible until ready
            Positioned.fill(
              child: AnimatedOpacity(
                opacity: _loading ? 0.0 : 1.0,
                duration: const Duration(milliseconds: 150),
                child: DescopeFlowView(
                  config: DescopeFlowConfig(
                    url: '<URL for where the flow is hosted, for example: https://api.descope.com/login/[MY_PROJECT_ID]?flow=[MY_FLOW_ID]>',
                    // Optional parameters - will be required according to the flow you're using
                    // and the authentication methods it contains
                    androidOAuthNativeProvider: 'google', // an example supporting native Google Sign In on Android
                    iosOAuthNativeProvider: 'apple', // an example supporting native Sign In with Apple on iOS
                    oauthRedirect: 'https://YOUR_DEEP_LINK_URL/oauth', // android only - needs to match the app link you configured in your manifest
                    magicLinkRedirect: 'https://YOUR_DEEP_LINK_URL/magiclink', // needs to match the app link you configured in your manifest or associated domain
                  ),
                  callbacks: DescopeFlowCallbacks(
                    onReady: () {
                      // simple reveal animation when the flow is ready
                      if (!mounted) return;
                      setState(() => _loading = false);
                    },
                    onSuccess: (AuthenticationResponse res) {
                      // handle the successful authentication response, assuming the model calls
                      // something along the lines of:
                      // final session = DescopeSession.fromAuthenticationResponse(res);
                      // Descope.sessionManager.manageSession(session);
                      model.handleAuthResponse(res);
                      if (context.mounted) context.pop();
                    },
                    onError: (DescopeException e) {
                      // handle any errors that might occur during the flow.
                      // errors generally mean that the flow is unrecoverable and
                      // needs to be restarted.
                      model.handleError(e);
                      if (context.mounted) context.pop();
                    },
                  ),
                  controller: model.descopeFlowController,
                ),
              ),
            ),
            if (_loading) const Center(child: CircularProgressIndicator()),
          ],
        ),
      ),
    );
  }
}

Authentication Methods

We can authenticate users by using any combination of the authentication methods supported by this SDK. Here are some examples for how to authenticate users:

OTP Authentication

Send a user a one-time password (OTP) using your preferred delivery method (email / SMS). An email address or phone number must be provided accordingly.

The user can either sign up, sign in or sign up or in

// Every user must have a loginID. All other user information is optional
final maskedEmail = await Descope.otp.signUp(method: DeliveryMethod.email, loginId: '[e-mail]',
    details: SignUpDetails(name: 'Desmond Copeland'));

The user will receive a code using the selected delivery method. Verify that code using:

final authResponse = await Descope.otp.verify(method: DeliveryMethod.email, loginId: '[e-mail]', code: '123456');

Magic Link

Send a user a Magic Link using your preferred delivery method (email / SMS). The Magic Link will redirect the user to a page where the attached token needs to be verified. Depending on the target, it might be required to use deep links to return to the app. This redirection can be configured in code, or globally in the Descope Console

The user can either sign up, sign in or sign up or in

// If configured globally, the redirect URL is optional. If provided however, it will be used
// instead of any global configuration
await Descope.magicLink.signUp(method: DeliveryMethod.email, loginId: '[e-mail]',
    details: SignUpDetails(name: 'Desmond Copeland'), redirectUrl: 'https://your-redirect-address.com/verify');

To verify a magic link, your redirect page must call the validation function on the token (t) parameter (https://your-redirect-address.com/verify?t=<token>):

final authResponse = await Descope.magicLink.verify(token: '<token>');

Enchanted Link

Using the Enchanted Link APIs enables users to sign in by clicking a link delivered to their email address. The email will include 3 different links, and the user will have to click the right one, based on the 2-digit number that is displayed when initiating the authentication process.

This method is similar to Magic Link but differs in two major ways:

• The user must choose the correct link out of the three, instead of having just one single link.
• This supports cross-device clicking, meaning the user can try to log in on one device, like a computer, while clicking the link on another device, for instance a mobile phone.

The Enchanted Link will redirect the user to page where the its token needs to be verified. This redirection can be configured in code per request, or set globally in the Descope Console.

The user can either sign up, sign in or sign up or in

// If configured globally, the redirect URL is optional. If provided however, it will be used
// instead of any global configuration
final enchantedLinkResponse = await Descope.enchantedLink.signUp(loginId: '[e-mail]',
    details: SignUpDetails(name: 'Desmond Copeland'), redirectUrl: 'https://your-redirect-address.com/verify');

Inform the user which link is the correct one, using enchantedLinkResponse.linkId. After that, start polling for a valid session. It will be returned once the user clicks on the correct link (assuming the redirected web page calls the validate method);

final authResponse = await Descope.enchantedLink.pollForSession(pendingRef: enchantedLinkResponse.pendingRef);

OAuth

Users can authenticate using their social logins, using the OAuth protocol. Configure your OAuth settings on the Descope console. It is recommended to use flutter_web_auth to handle the redirect and code extraction.

To start a flow call:

import 'package:flutter_web_auth/flutter_web_auth.dart';

// Choose an oauth provider out of the supported providers
// If configured globally, the redirect URL is optional. If provided however, it will be used
// instead of any global configuration.
final authUrl = await Descope.oauth.start(provider: OAuthProvider.google, redirectUrl: 'exampleauthschema://my-app.com/handle-oauth');

Take the generated URL and authenticate the user using flutter_web_auth (read more here). The user will authenticate with the authentication provider, and will be redirected back to the redirect URL, with an appended code HTTP URL parameter. Exchange it to validate the user:

// Redirect the user to the returned URL to start the OAuth redirect chain
final result = await FlutterWebAuth.authenticate(url: authUrl, callbackUrlScheme: 'exampleauthschema');
// Extract the returned code
final code = Uri.parse(result).queryParameters['code'];
// Exchange code for an authentication response
final authResponse = await Descope.oauth.exchange(code: code!);

When running in iOS or Android, you can leverage the Sign in with Apple and Sign in with Google features to show a native authentication view that allows the user to login using the account they are already logged into on their device. Note that your application will need some configuration to support native authentication. See the function documentation for more details.

void loginWithOAuth() async {
  AuthenticationResponse response;
  if (!kIsWeb && Platform.isIOS) {
    // created a custom Apple provider using the app bundle identifier as the Client ID
    response = await Descope.oauth.native(provider: OAuthProvider.named("ios"));
  } else if (!kIsWeb && Platform.isAndroid) {
    // created a custom Google provider for implicit authentication
    response = await Descope.oauth.native(provider: OAuthProvider.named("android"));
  } else {
    // regular web OAuth
  }
  final session = DescopeSession.fromAuthenticationResponse(response)
  // ...
}

SSO/SAML

Users can authenticate to a specific tenant using SAML or Single Sign On. Configure your SSO/SAML settings on the Descope console. It is recommended to use flutter_web_auth to handle the redirect and code extraction.

To start a flow call:

// Choose which tenant to log into
// If configured globally, the return URL is optional. If provided however, it will be used
// instead of any global configuration.
final authUrl = await Descope.sso.start(emailOrTenantId: 'my-tenant-ID', redirectUrl: 'exampleauthschema://my-app.com/handle-saml');

Take the generated URL and authenticate the user using flutter_web_auth (read more here). The user will authenticate with the authentication provider, and will be redirected back to the redirect URL, with an appended code HTTP URL parameter. Exchange it to validate the user:

// Redirect the user to the returned URL to start the OAuth redirect chain
final result = await FlutterWebAuth.authenticate(url: authUrl, callbackUrlScheme: 'exampleauthschema');
// Extract the returned code
final code = Uri.parse(result).queryParameters['code'];
// Exchange code for an authentication response
final authResponse = await Descope.sso.exchange(code: code!);

Passkeys

Users can authenticate by creating or using a passkey. Configure your Passkey/WebAuthn settings on the Descope console. Make sure it is enabled and that the top level domain is configured correctly.

After that, for iOS go through Apple's Supporting passkeys guide, in particular be sure to have an associated domain configured for your app with the webcredentials service type, whose value matches the top level domain you configured in the Descope console earlier. For Android, please follow the Add support for Digital Asset Links setup, as described in the official Google docs.

try {
    showLoading(true);
    final authResponse = await Descope.passkey.signUpOrIn(loginId: loginId);
    final session = DescopeSession.fromAuthenticationResponse(authResponse);
    Descope.sessionManager.manageSession(session);
    showHomeScreen() 
} on DescopeException catch (e) {
    if (e == DescopeException.passkeyCancelled) {
      showLoading(false)
      print("Authentication cancelled")
    } else {
      showError(error)
    }
}

TOTP Authentication

The user can authenticate using an authenticator app, such as Google Authenticator. Sign up like you would using any other authentication method. The sign up response will then contain a QR code image that can be displayed to the user to scan using their mobile device camera app, or the user can enter the key manually or click on the link provided by the provisioningURL.

Existing users can add TOTP using the update function.

// Every user must have a loginID. All other user information is optional
final totpResponse = await Descope.totp.signUp(loginId: '[e-mail]', details: SignUpDetails(name: 'Desmond Copeland'));

// Use one of the provided options to have the user add their credentials to the authenticator
// totpResponse.provisioningUrl
// totpResponse.image
// totpResponse.key

There are 3 different ways to allow the user to save their credentials in their authenticator app - either by clicking the provisioning URL, scanning the QR image or inserting the key manually. After that, signing in is done using the code the app produces.

final authResponse = await Descope.totp.verify(loginId: '[e-mail]', code: '123456');

Password Authentication

It is possible to authenticate a user using a password. Passwords are a legacy way of authentication. Each of the passwordless methods above are better from a security and usability perspective. Passwords are disabled by default in the Descope Console password settings. Make sure to enable it before attempting authentication. The user can either sign up or sign in

// Every user must have a loginID. All other user information is optional
final authResponse = await Descope.password.signUp(loginId: '[e-mail]', password: 'cleartext-password',
    details: SignUpDetails(name: 'Desmond Copeland'));

Update or Replace Password

// It's possible to update a user's password when the user has an active session:
await Descope.password.update(loginId: '[e-mail]', newPassword: 'newSecurePassword456!', refreshJwt: "user-refresh-jwt");

// Or to replace a user's password by providing their current password.
// this is especially true when a password expires:
final authResponse = await Descope.password.replace(loginId: '[e-mail]', oldPassword: 'SecurePassword123!', newPassword: 'NewSecurePassword456!');

Send Password Reset Email

Initiate a password reset (update) by sending a magic link email, that needs to be validated like any other magic link. After authenticating the user using this magic link, it's possible to use the update function to update the user's password:

await Descope.password.sendReset(loginId: '[e-mail]', redirectUrl: "exampleauthschema://my-app.com/handle-reset");

Additional Information

To learn more please see the Descope Documentation and API reference page.

Contact Us

If you need help you can email Descope Support

License

The Descope SDK for Flutter is licensed for use under the terms and conditions of the MIT license Agreement.