Flutterでアプリ開発・Auth0を実装（Android編）

class MainActivity: FlutterActivity() {
}

class MainActivity: FlutterActivity(), MethodCallHandler { // <-- Flutter側からメッセージを受け取るためのハンドラを設定
    companion object {
        // Method Channelのチャンネル名になります。
        // この名前で各プラットフォーム間の連携を行うことになります。
        private const val AUTH0_CHANNEL = "com.example.flutterauthapp/auth0"
    }

    private lateinit var channel: MethodChannel

    override fun configureFlutterEngine(@NonNull flutterEngine: FlutterEngine) {
        super.configureFlutterEngine(flutterEngine)
        // MethodChannelにてチャンネル名を登録
        channel = MethodChannel(flutterEngine.dartExecutor.binaryMessenger, AUTH0_CHANNEL)
        // methodCannelに対して以下のonMethodCallを登録、Flutter側からの呼び出しに応答する
        channel.setMethodCallHandler(this)
    }

    // Flutter側からコールされたときの処理を実装
    override fun onMethodCall(call: MethodCall, result: Result) {
        when (call.method) {
            "isLogin" -> {
                // ログイン有無の状態取得処理を実装
            }
            "login" -> {
                // ログイン処理を実装
            }
            "getUserProfile" -> {
                // ユーザー情報取得処理を実装
            }
            "logout" -> {
                // ログアウト処理を実装
            }
            else -> result.notImplemented()
        }
    }
}

<?xml version="1.0" encoding="utf-8"?>
<resources>
    <string name="com_auth0_client_id">XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX</string>
    <string name="com_auth0_domain">OOOOOO.auth0.com</string>
    <string name="com_auth0_scheme">demo</string>
</resources>

import android.app.Activity
import com.auth0.android.Auth0
import com.auth0.android.authentication.AuthenticationAPIClient
import com.auth0.android.authentication.AuthenticationException
import com.auth0.android.authentication.storage.CredentialsManagerException
import com.auth0.android.authentication.storage.SecureCredentialsManager
import com.auth0.android.authentication.storage.SharedPreferencesStorage
import com.auth0.android.callback.Callback
import com.auth0.android.provider.WebAuthProvider
import com.auth0.android.result.Credentials
import com.auth0.android.result.UserProfile
import io.flutter.plugin.common.MethodChannel

class Auth0Utils(private val activity: Activity) {
    private val auth0: Auth0 =
            Auth0(
                    activity.getString(R.string.com_auth0_client_id),
                    activity.getString(R.string.com_auth0_domain)
            )
    private val secureCredentialsManager =
            SecureCredentialsManager(
                    activity.applicationContext,
                    AuthenticationAPIClient(auth0),
                    SharedPreferencesStorage(activity.applicationContext)
            )

    fun isLogin(result: MethodChannel.Result) {
        result.success(secureCredentialsManager.hasValidCredentials())
    }

    fun login(result: MethodChannel.Result) {
        WebAuthProvider.login(auth0)
                .withScheme(activity.getString(R.string.com_auth0_scheme))
                .withScope("openid profile email")
                .start(activity, object : Callback<Credentials, AuthenticationException> {
                    override fun onFailure(error: AuthenticationException) {
                        result.error(error.getCode(), error.getDescription(), error)
                        return
                    }

                    override fun onSuccess(credentials: Credentials) {
                        try {
                            secureCredentialsManager.saveCredentials(credentials)
                            val credentialsMap = HashMap<String, Any?>()
                            credentialsMap["idToken"] = credentials.idToken
                            credentialsMap["accessToken"] = credentials.accessToken
                            credentialsMap["expiresAt"] = credentials.expiresAt.time
                            credentialsMap["refreshToken"] = credentials.refreshToken
                            credentialsMap["type"] = credentials.type
                            credentialsMap["scope"] = credentials.scope
                            credentialsMap["recoveryCode"] = credentials.recoveryCode
                            result.success(credentialsMap)
                        } catch (e:Exception) {
                            secureCredentialsManager.clearCredentials()
                            result.error(e.javaClass.simpleName, e.message, e)
                        }
                    }
                })
    }

    fun getUserProfile(result: MethodChannel.Result) {
        secureCredentialsManager.getCredentials(object : Callback<Credentials, CredentialsManagerException> {
            override fun onFailure(error: CredentialsManagerException) {
                result.error("CredentialsManagerException", error.message, error)
                return
            }

            override fun onSuccess(credentials: Credentials) {
                try {
                    val accessToken = credentials.accessToken
                    val authenticationClient = AuthenticationAPIClient(auth0)
                    authenticationClient.userInfo(accessToken)
                            .start(object : Callback<UserProfile, AuthenticationException> {
                                override fun onSuccess(userInfo: UserProfile) {
                                    val userInfoMap = HashMap<String, Any?>()
                                    userInfoMap["id"] = userInfo.getId()
                                    userInfoMap["name"] = userInfo.name
                                    userInfoMap["nickname"] = userInfo.nickname
                                    userInfoMap["pictureURL"] = userInfo.pictureURL
                                    userInfoMap["email"] = userInfo.email
                                    userInfoMap["isEmailVerified"] = userInfo.isEmailVerified
                                    userInfoMap["familyName"] = userInfo.familyName
                                    userInfoMap["givenName"] = userInfo.givenName
                                    userInfoMap["createdAt"] = userInfo.createdAt?.time?:0

                                    result.success(userInfoMap)
                                }

                                override fun onFailure(error: AuthenticationException) {
                                    result.error(error.getCode(), error.getDescription(), error)
                                }
                            })
                } catch (e:Exception) {
                    secureCredentialsManager.clearCredentials()
                    result.error(e.javaClass.simpleName, e.message, e)
                }
            }
        })
    }

    fun logout(result: MethodChannel.Result) {
        WebAuthProvider.logout(auth0)
                .withScheme(activity.getString(R.string.com_auth0_scheme))
                .start(activity, object : Callback<Void?, AuthenticationException> {
                    override fun onFailure(error: AuthenticationException) {
                        result.error(error.getCode(), error.getDescription(), error)
                        return
                    }

                    override fun onSuccess(void: Void?) {
                        secureCredentialsManager.clearCredentials()
                        result.success(true)
                    }
                })
    }
}

class MainActivity: FlutterActivity(), MethodCallHandler {
    companion object {
        // Method Channelのチャンネル名になります。
        // この名前で各プラットフォーム間の連携を行うことになります。
        private const val AUTH0_CHANNEL = "com.example.flutterauthapp/auth0"
    }

    private lateinit var channel: MethodChannel
    private lateinit var auth0Utils: Auth0Utils // <--- フィールドに追加

    override fun configureFlutterEngine(@NonNull flutterEngine: FlutterEngine) {
        super.configureFlutterEngine(flutterEngine)

        auth0Utils = Auth0Utils(this) // <--- ここでインスタンス生成

        // MethodChannelにてチャンネル名を登録
        channel = MethodChannel(flutterEngine.dartExecutor.binaryMessenger, AUTH0_CHANNEL)
        // methodCannelに対して以下のonMethodCallを登録、Flutter側からの呼び出しに応答する
        channel.setMethodCallHandler(this)
    }

    // Flutter側からコールされたときの処理を実装
    override fun onMethodCall(call: MethodCall, result: Result) {
        when (call.method) {
            "isLogin" -> {
                // ログイン有無の状態取得処理を実装
                auth0Utils.isLogin(result) // <--- ここに追加
            }
            "login" -> {
                // ログイン処理を実装
                auth0Utils.login(result) // <--- ここに追加
            }
            "getUserProfile" -> {
                // ユーザー情報取得処理を実装
                auth0Utils.getUserProfile(result) // <--- ここに追加
            }
            "logout" -> {
                // ログアウト処理を実装
                auth0Utils.logout(result) // <--- ここに追加
            }
            else -> result.notImplemented()
        }
    }
}

dependencies:
  flutter:
    sdk: flutter


  # The following adds the Cupertino Icons font to your application.
  # Use with the CupertinoIcons class for iOS style icons.
  cupertino_icons: ^1.0.2
  flutter_riverpod: ^1.0.0-dev.7  # <-- これを追加

class Credentials {
  late String idToken;
  late String accessToken;
  late String type;
  String? refreshToken;
  late int expiresAt;
  String? scope;
  String? recoveryCode;

  Credentials.createFromMap(Map<String, dynamic> data) {
    idToken = data["idToken"];
    accessToken = data["accessToken"];
    type = data["type"];
    refreshToken = data["refreshToken"];
    expiresAt = data["expiresAt"];
    scope = data["scope"];
    recoveryCode = data["recoveryCode"];
  }
}

class UserProfile {
  String? id;
  String? name;
  String? nickname;
  String? pictureURL;
  String? email;
  bool? isEmailVerified;
  String? familyName;
  String? givenName;
  int? createdAt;

  UserProfile.createFromMap(Map<String, dynamic> data) {
    id = data['id'];
    name = data['name'];
    nickname = data['nickname'];
    pictureURL = data['pictureURL'];
    email = data['email'];
    isEmailVerified = data['isEmailVerified'];
    familyName = data['familyName'];
    givenName = data['givenName'];
    createdAt = data['createdAt'];
  }
}

import 'package:flutterauthapp/entity/user_profile.dart';
import 'package:flutter/material.dart';
import 'package:flutter/services.dart';
import 'package:flutter_riverpod/flutter_riverpod.dart';

final myHomeViewModelProvider = ChangeNotifierProvider((ref) => MyHomeViewModel());

class MyHomeViewModel extends ChangeNotifier {

  // MethodChannel名はAndroid側と同一にしておくこと
  static const MethodChannel _channel = MethodChannel('com.example.flutterauthapp/auth0');

  String loginButtonlabel = "Login";

  String name = "";
  String email = "";
  String imageUrl = "";

  Future<bool> isLogin() async {
    return await _channel.invokeMethod('isLogin');
  }

  Future<bool> login() async {
    try {
      Map<String, dynamic>? loginData = await _channel.invokeMapMethod<String, dynamic>('login');
      if (loginData != null) {
        loginButtonlabel = "Logout";
        notifyListeners();
        return true;
      }
      return false;
    } catch(e) {
      debugPrint(e.toString());
      return false;
    }
  }

  Future<bool> getUserProfile() async {
    try {
      Map<String, dynamic>? userProfile = await _channel.invokeMapMethod<String, dynamic>('getUserProfile');
      if (userProfile != null) {
        var user = UserProfile.createFromMap(userProfile);
        name = user.name ?? "";
        email = user.email ?? "";
        imageUrl = user.pictureURL ?? "";
        notifyListeners();
        return true;
      }
      return false;
    } catch(e) {
      debugPrint(e.toString());
      return false;
    }
  }

  Future<void> logout() async {
    try {
      bool isSuccess = await _channel.invokeMethod('logout');
      if (isSuccess) {
        loginButtonlabel = "Login";
        name = "";
        email = "";
        imageUrl = "";
        notifyListeners();
      }
    } catch(e) {
      debugPrint(e.toString());
    }
  }

}

import 'package:flutter/material.dart';
import 'package:flutter_riverpod/flutter_riverpod.dart';

import 'my_app.dart';

void main() {
  runApp(const ProviderScope(child: MyApp()));
}

import 'package:flutter/material.dart';
import 'my_home_page.dart';

class MyApp extends StatelessWidget {
  const MyApp({Key? key}) : super(key: key);

  // This widget is the root of your application.
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Flutter Demo',
      theme: ThemeData(
        primarySwatch: Colors.blue,
      ),
      home: MyHomePage(title: 'Flutter Demo Home Page'),
    );
  }
}

import 'package:flutter/material.dart';
import 'package:flutter_riverpod/flutter_riverpod.dart';
import 'my_home_page_viewmodel.dart';

class MyHomePage extends ConsumerWidget {

  final String title;

  MyHomePage({Key? key, required this.title}) : super(key: key);

  @override
  Widget build(BuildContext context, WidgetRef ref) {
    final _viewModel = ref.watch(myHomeViewModelProvider);
    return Scaffold(
      appBar: AppBar(
        title: Text(title),
      ),
      body: Center(
        child: Column(
          mainAxisAlignment: MainAxisAlignment.center,
          children: <Widget>[
            const Text(
              'Auth0 Test App',
            ),
            SizedBox(
              child: ElevatedButton(
                onPressed: () async {
                  var isLogin = await _viewModel.isLogin();
                  if (isLogin) {
                    await _viewModel.logout();
                  } else {
                    bool isSuccess = await _viewModel.login();
                    if (isSuccess) {
                      await _viewModel.getUserProfile();
                    }
                  }
                },
                child: Text(_viewModel.loginButtonlabel),
              ),
            ),
            _viewModel.imageUrl.isNotEmpty?Image.network(_viewModel.imageUrl):Container(),
            Text(
              'name: ${_viewModel.name}',
            ),
            Text(
              'email: ${_viewModel.email}',
            ),
          ],
        ),
      ),
    );
  }
}