Auth0-How to use with Flutter

Its very simple to get started with flutter auth0

Have a class for auth0 and call this at the places you need them. But also be sure to set the constants AUTH0_DOMAIN, AUTH0_CLIENT_ID, AUTH0_REDIRECT_URI, AUTH0_ISSUER

class Auth0 {

  final FlutterAppAuth appAuth = FlutterAppAuth();

  Map<String, Object> parseIdToken(String idToken) {
    final List<String> parts = idToken.split('.');
    assert(parts.length == 3);
    return jsonDecode(
        utf8.decode(base64Url.decode(base64Url.normalize(parts[1]))));
  }

  Future<Map<String, Object>> getUserDetails(String accessToken) async {
    const String url = 'https://$AUTH0_DOMAIN/userinfo';
    final http.Response response = await http.get(
      url,
      headers: <String, String>{'Authorization': 'Bearer $accessToken'},
    );
    if (response.statusCode == 200) {
      return jsonDecode(response.body);
    } else {
      throw Exception('Failed to get user details');
    }
  }

  Future<void> loginAction() async {
      isBusy = true;
      errorMessage = 'Error! - ';

    try {
      final AuthorizationTokenResponse result =
          await appAuth.authorizeAndExchangeCode(
        AuthorizationTokenRequest(
          AUTH0_CLIENT_ID,
          AUTH0_REDIRECT_URI,
          issuer: 'https://$AUTH0_DOMAIN',
          scopes: <String>['openid', 'email', 'profile', 'offline_access'],
          promptValues: ['login']
        ),
      );

      final Map<String, Object> idToken = parseIdToken(result.idToken);
      final Map<String, Object> profile =
          await getUserDetails(result.accessToken);


        isBusy = false;
        name = idToken['name'];
        email = profile['email'];
        picture = profile['picture'];


    } on Exception catch (e, s) {
      print('login error: $e - stack: $s');

        isBusy = false;
        errorMessage = e.toString();
    }
  }

Instead of using a boolean for checking isLoggedIn try saving the token in the localstorage and that will set the state as is.

There's an auth0 package for flutter to use Auth0 API provides login, logout and access APIs for authentication in your App. However, you need to make changes inside android and ios files in your flutter project. You need to configure your callbacks and application settings for that, The author has their example on github that you should check out.

I would advise you to follow the blog post provided by the Auth0 team - Get Started with Flutter Authentication

For Flutter Web App, I am making a wrapper around Auth0 JS SPA SDK.

GitHub: https://github.com/anthonychwong/auth0-flutter-web

Pub.dev: https://pub.dev/packages/auth0_flutter_web

import 'package:auth0_flutter_web/auth0_flutter_web.dart';

Auth0 auth0 = await createAuth0Client(
  Auth0CreateOptions(
    domain: '-- domain of the universal login page --',
    client_id: '-- id of your app --',
  )
);

String token = await auth0.getTokenWithPopup();

It is in very early stage and PRs are welcome.