スキルKnowledge Worksecurity

🔐auth0-flutter-web

プラグイン: Auth0
ライセンス: Apache-2.0
ソース: GitHub で見る ↗

説明

Auth0ログイン/ログアウトをFlutter Webアプリケーションに追加する場合に使用します。 Webプラットフォームでauth0_flutterを統合します。ユーザーが「Flutter Webアプリにログイン機能を追加したい」と述べた場合でも使用してください。

原文を表示

Use when adding Auth0 login or logout to a Flutter web application. Integrates auth0_flutter on the web platform — use even if the user says "add login to my Flutter web app".

ユースケース

✓Flutter Webアプリに認証機能を追加する
✓Auth0でログイン機能を実装する
✓ユーザー認証とログアウト機能を統合する

本文

Auth0 Flutter Web Integration

auth0_flutter is the official Auth0 SDK for Flutter applications. On the web platform, it wraps the Auth0 SPA JS SDK to provide browser-based authentication via redirect or popup flows with built-in credential caching and automatic token renewal.

Agent instruction: The current SDK version is 2.1.0. Use this version in all dependency lines below. If you need to verify, run flutter pub add auth0_flutter which will resolve the latest compatible version automatically.

When NOT to Use

Flutter mobile (iOS/Android): Use auth0-flutter-native — mobile uses a different platform interface with Web Auth via system browser
Native iOS (Swift): Use auth0-swift
Native Android (Kotlin/Java): Use auth0-android
React SPA: Use auth0-react
Angular SPA: Use auth0-angular
Vue SPA: Use auth0-vue
Node.js/Express servers: Use auth0-express

Prerequisites

Flutter 3.24.0+
Dart 3.5.0+
Auth0 account — Sign up free
Auth0 CLI — install instructions (used to create and configure the Auth0 application)

Quick Start Workflow

Agent instruction: Follow these steps in order. If you encounter an error at any step, attempt to fix it up to 5 times before calling AskUserQuestion to ask the user for guidance. Always search existing code first — if there are existing login/logout handlers, hook into them rather than creating new ones.

Step 1 — Install SDK

Agent instruction: Check the project directory for pubspec.yaml. If present, add the dependency. If not found, this is not a Flutter project — ask the user.

Run in the project root:
flutter pub add auth0_flutter
Verify the dependency was added to pubspec.yaml:
dependencies:
  auth0_flutter: ^2.1.0

Step 2 — Configure Auth0

Note: For Single Page Applications, the Auth0 Domain and Client ID are public configuration (not secrets). A SPA uses PKCE with no client secret, and these values ship in the browser bundle. Pass them directly to Auth0Web(domain, clientId) — there is no need to store them in environment variables or hide them.

Agent instruction:

If Auth0 credentials (domain AND client ID) are already in the user's prompt: Proceed to Step 3 and use those values directly in the Auth0Web(...) constructor.

If no credentials are provided: Create the application with the Auth0 CLI — do NOT ask the user to create or configure an Auth0 application manually in the Dashboard. Always use the CLI path.

Follow Setup Guide — Auth0 Configuration for the pre-flight checks and the auth0 apps create command.

Step 3 — Add Auth0 SPA JS to index.html

Agent instruction:

Locate the web entry point: web/index.html

Add the Auth0 SPA JS script tag inside <head>:
<script src="https://cdn.auth0.com/js/auth0-spa-js/2.1/auth0-spa-js.production.js" defer></script>
If web/index.html does not exist, the user may need to run flutter create . --platforms=web to add web support.

Step 4 — Configure Callback URLs

Agent instruction:

Determine the app's web URL. For local development, default is http://localhost:3000 (when running with --web-port 3000).

Ask the user via AskUserQuestion: "What port will you run your Flutter web app on locally? (default: 3000)"

Register the callback URLs using the Auth0 CLI (substitute real values for CLIENT_ID, APP_URL):
auth0 apps update CLIENT_ID \
  --callbacks "APP_URL" \
  --logout-urls "APP_URL" \
  --web-origins "APP_URL" \
  --no-input
For production, also add the production URL to each list.

Step 5 — Implement Authentication

Agent instruction: Search the project for the main app entry point (main.dart). Determine the state management approach:

Look for provider, riverpod, bloc, GetX, or mobx imports

If none found, use basic StatefulWidget with setState

Then follow only the matching path below. If ambiguous, ask via AskUserQuestion: "Which state management approach does your Flutter app use — Provider, Riverpod, Bloc, or basic setState?"

Basic StatefulWidget (Default)

Agent instruction: Create an AuthService class, then wire it into the app's root widget. Search for the MaterialApp or CupertinoApp widget and update accordingly.

// lib/auth_service.dart
import 'package:auth0_flutter/auth0_flutter.dart';
import 'package:auth0_flutter/auth0_flutter_web.dart';

class AuthService {
  late final Auth0Web _auth0;
  Credentials? _credentials;

  AuthService({required String domain, required String clientId}) {
    _auth0 = Auth0Web(domain, clientId);
  }

  bool get isAuthenticated => _credentials != null;
  Credentials? get credentials => _credentials;
  UserProfile? get user => _credentials?.user;

  /// Call on app startup to restore session from cache
  Future<void> onLoad() async {
    _credentials = await _auth0.onLoad();
  }

  /// Redirect to Auth0 Universal Login
  Future<void> loginWithRedirect({String? redirectUrl}) async {
    await _auth0.loginWithRedirect(
      redirectUrl: redirectUrl,
      scopes: {'openid', 'profile', 'email', 'offline_access'},
    );
  }

  /// Open Auth0 login in a popup window
  Future<void> loginWithPopup() async {
    _credentials = await _auth0.loginWithPopup(
      scopes: {'openid', 'profile', 'email', 'offline_access'},
    );
  }

  /// Get cached credentials (auto-refreshes if expired)
  Future<Credentials> getCredentials() async {
    final creds = await _auth0.credentials();
    _credentials = creds;
    return creds;
  }

  /// Check if valid credentials exist
  Future<bool> hasValidCredentials() async {
    return await _auth0.hasValidCredentials();
  }

  /// Logout and redirect back to the app
  Future<void> logout({String? returnToUrl}) async {
    await _auth0.logout(returnToUrl: returnToUrl);
    _credentials = null;
  }
}

// lib/main.dart
import 'package:flutter/material.dart';
import 'auth_service.dart';

void main() {
  runApp(const MyApp());
}

class MyApp extends StatefulWidget {
  const MyApp({super.key});

  @override
  State<MyApp> createState() => _MyAppState();
}

class _MyAppState extends State<MyApp> {
  final _authService = AuthService(
    domain: 'YOUR_AUTH0_DOMAIN',
    clientId: 'YOUR_AUTH0_CLIENT_ID',
  );
  bool _isLoading = true;

  @override
  void initState() {
    super.initState();
    _initAuth();
  }

  Future<void> _initAuth() async {
    await _authService.onLoad();
    setState(() => _isLoading = false);
  }

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      home: _isLoading
          ? const Scaffold(body: Center(child: CircularProgressIndicator()))
          : _authService.isAuthenticated
              ? HomeScreen(authService: _authService)
              : LoginScreen(authService: _authService),
    );
  }
}

class LoginScreen extends StatelessWidget {
  final AuthService authService;
  const LoginScreen({super.key, required this.authService});

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      body: Center(
        child: ElevatedButton(
          onPressed: () => authService.loginWithRedirect(),
          child: const Text('Log In'),
        ),
      ),
    );
  }
}

class HomeScreen extends StatelessWidget {
  final AuthService authService;
  const HomeScreen({super.key, required this.authService});

  @override
  Widget build(BuildContext context) {
    final user = authService.user;
    return Scaffold(
      appBar: AppBar(
        title: const Text('Home'),
        actions: [
          IconButton(
            onPressed: () => authService.logout(
              returnToUrl: Uri.base.origin,
            ),
            icon: const Icon(Icons.logout),
          ),
        ],
      ),
      body: Center(
        child: Column(
          mainAxisAlignment: MainAxisAlignment.center,
          children: [
            if (user?.pictureUrl != null)
              CircleAvatar(
                backgroundImage: NetworkImage(user!.pictureUrl.toString()),
                radius: 40,
              ),
            const SizedBox(height: 16),
            Text('Welcome, ${user?.name ?? 'User'}!'),
            Text(user?.email ?? ''),
          ],
        ),
      ),
    );
  }
}

Provider (State Management)

Agent instruction: If the project uses provider, create AuthService as a ChangeNotifier and inject it via ChangeNotifierProvider at the app root.

// lib/auth_service.dart
import 'package:flutter/foundation.dart';
import 'package:auth0_flutter/auth0_flutter.dart';
import 'package:auth0_flutter/auth0_flutter_web.dart';

class AuthService extends ChangeNotifier {
  late final Auth0Web _auth0;
  Credentials? _credentials;
  bool _isLoading = true;

  AuthService({required String domain, required String clientId}) {
    _auth0 = Auth0Web(domain, clientId);
  }

  bool get isAuthenticated => _credentials != null;
  bool get isLoading => _isLoading;
  UserProfile? get user => _credentials?.user;

  Future<void> init() async {
    _credentials = await _auth0.onLoad();
    _isLoading = false;
    notifyListeners();
  }

  Future<void> loginWithRedirect() async {
    await _auth0.loginWithRedirect(
      scopes: {'openid', 'profile', 'email', 'offline_access'},
    );
  }

  Future<void> loginWithPopup() async {
    _credentials = await _auth0.loginWithPopup(
      scopes: {'openid', 'profile', 'email', 'offline_access'},
    );
    notifyListeners();
  }

  Future<void> logout() async {
    await _auth0.logout(returnToUrl: Uri.base.origin);
    _credentials = null;
    notifyListeners();
  }
}

// lib/main.dart — wrap with ChangeNotifierProvider
import 'package:provider/provider.dart';

void main() {
  runApp(
    ChangeNotifierProvider(
      create: (_) => AuthService(
        domain: 'YOUR_AUTH0_DOMAIN',
        clientId: 'YOUR_AUTH0_CLIENT_ID',
      )..init(),
      child: const MyApp(),
    ),
  );
}

For complete patterns with Riverpod, Bloc, and advanced scenarios, see Integration Patterns.

Step 6 — Verify Build

Agent instruction: Run a build to verify the integration compiles without errors:
flutter build web
Then run the app locally to test:
flutter run -d chrome --web-port 3000
If the build fails, review error messages and fix up to 5 times before asking the user.

Detailed Documentation

Setup Guide — Auth0 application creation via the Auth0 CLI, web/index.html setup, callback URL registration
Integration Patterns — Redirect login, popup login, credential management, state management patterns, organization support, error handling
API Reference & Testing — Full API reference, configuration options, claims reference, testing checklist, troubleshooting

Common Mistakes

Mistake	Fix
Auth0 app type not set to Single Page Application	In Auth0 Dashboard, select "Single Page Application" when creating the application
Missing Auth0 SPA JS script in `web/index.html`	Add `<script src="https://cdn.auth0.com/js/auth0-spa-js/2.1/auth0-spa-js.production.js" defer></script>` to `<head>`
Not calling `onLoad()` on app startup	Always call `onLoad()` in `initState()` or equivalent to restore sessions after redirect
Missing `Allowed Web Origins` in Auth0 Dashboard	Add your app URL (e.g., `http://localhost:3000`) to Allowed Web Origins — required for silent token renewal
Using `auth0_flutter` mobile API on web	Import both `package:auth0_flutter/auth0_flutter.dart` (for types like `Credentials`, `UserProfile`) AND `package:auth0_flutter/auth0_flutter_web.dart` (for `Auth0Web` class)
Missing base import causes type errors	`Credentials` and `UserProfile` are exported from `auth0_flutter.dart`, not `auth0_flutter_web.dart` — you need both imports
Callback URL mismatch	Ensure `Allowed Callback URLs` matches the exact URL where your app runs (including port)
Not adding `--web-port` when running locally	Use `flutter run -d chrome --web-port 3000` to ensure consistent port matching callback URLs
Popup blocked by browser	`loginWithPopup()` must be called from a direct user interaction (button click); cannot be called from `initState()`
Missing `offline_access` scope	Add `'offline_access'` to scopes set to enable refresh token rotation for silent renewal
CORS errors on token endpoint	Ensure `Allowed Web Origins` is configured in Auth0 Dashboard (not just Callback URLs)

References

原文・著作権は Anthropic および各プラグイン作者に帰属します。日本語訳は Claude API による自動翻訳です。