【Flutter × Go】退会処理：Firebase Auth削除時の「requires-recent-login」エラー対処法

[ERROR:flutter/runtime/dart_vm_initializer.cc(41)] Unhandled Exception: [firebase_auth/requires-recent-login] This operation is sensitive and requires recent authentication. Log in again before retrying this request.
#0      FirebaseAuthUserHostApi.delete (package:firebase_auth_platform_interface/src/pigeon/messages.pigeon.dart:1581:7)
<asynchronous suspension>
#1      MethodChannelUser.delete (package:firebase_auth_platform_interface/src/method_channel/method_channel_user.dart:35:7)
<asynchronous suspension>
#2      UserNotifier.deleteUser (package:clocky_app/api/user_notifier.dart:31:7)
<asynchronous suspension>

// lib/api/user_notifier.dart
class UserNotifier extends StateNotifier<User?> {
  final ApiClient apiClient;

  UserNotifier(this.apiClient) : super(null);

  Future<void> deleteUser() async {
    //  DBのデータを削除
    await apiClient.deleteUser(state?.uid ?? '');
    // Firebase Authデータを削除
    auth.User? currentUser = auth.FirebaseAuth.instance.currentUser;
    if (currentUser != null) {
      await currentUser.delete();
    }
    state = null;
  }
}

/// Deletes and signs out the user.
///
/// **Important**: this is a security-sensitive operation that requires the
/// user to have recently signed in. If this requirement isn't met, ask the
/// user to authenticate again and then call [User.reauthenticateWithCredential].
///
/// A [FirebaseAuthException] maybe thrown with the following error code:
/// - **requires-recent-login**:
///  - Thrown if the user's last sign-in time does not meet the security
///    threshold. Use [User.reauthenticateWithCredential] to resolve. This
///    does not apply if the user is anonymous.
Future<void> delete() async {
  return _delegate.delete();
}

# Install the latest version:
go install firebase.google.com/go/v4@latest

# Or install a specific version:
go install firebase.google.com/go/v4@4.13.0

// firebase_auth.go
package clocky_be

import (
	"context"

	firebase "firebase.google.com/go"
	"google.golang.org/api/option"
)

func FirebaseApp(config *Config) *firebase.App {
	opt := option.WithCredentialsJSON([]byte(config.GoogleApplicationCredentials))
	app, err := firebase.NewApp(context.Background(), nil, opt)
	if err != nil {
		panic("failed to initialize firebase app")
	}
	return app
}

// user_handler.go
type UserHandler struct {
	db *sqlx.DB
	sm ShadowManager
	app *firebase.App
}

func NewUserHandler(db *sqlx.DB, sm ShadowManager, app *firebase.App) *UserHandler {
    return &UserHandler{
        db:          db,
        sm:          sm,
        app: 		 　　 app,
    }
}

func (h *UserHandler) HandleDeleteUser(c echo.Context) error {
	uid := c.Get("uid").(string)
	if uid == "" {
		return echo.NewHTTPError(http.StatusBadRequest, "UID is required")
	}
	fmt.Printf("Want to delete uid: %vn", uid)

	// Firebase Authからユーザーを先に削除
	authClient, err := h.app.Auth(context.Background())
	if err != nil {
		c.Logger().Errorf("Failed to get Firebase Auth client: %v", err)
		return echo.NewHTTPError(http.StatusInternalServerError, "Failed to get Firebase Auth client")
	}
	if err := authClient.DeleteUser(context.Background(), uid); err != nil {
		c.Logger().Errorf("Failed to delete Firebase auth user: %v", err)
		return echo.NewHTTPError(http.StatusInternalServerError, "Failed to delete Firebase auth user")
	}

	// Firebase削除に成功したらデータベースからユーザーを削除
	if err := DeleteUser(h.db, uid); err != nil {
		c.Logger().Errorf("failed to delete user from DB: %v", err)
	}

	return c.NoContent(http.StatusNoContent)
}

// lib/api/api_client.dart
Future<void> deleteUser() async {
  final url = Uri.parse('$apiUrl/app/me');
  final headers = await apiHeaders();  // ここでユーザートークンを含むヘッダーを取得
  print("apiHeaders: $headers");
  final response = await http.delete(
    url,
    headers: headers,
  );

  if (response.statusCode != 204) {
    throw Exception('Failed to delete user: ${response.body}');
  }
}

// lib/api/user_notifier.dart
Future<void> deleteUser() async {
  try {
    await apiClient.deleteUser();  // APIクライアントを通じてユーザー削除をリクエスト
    state = null;  // 状態を更新
    print("User delete request sent successfully");
  } catch (e) {
    print('Failed to delete user: $e');
    throw e;  // エラーを再スローして、上位の処理でキャッチ可能に
  }
}

// lib/screens/home/customer_support_screen.dart
//ユーザー削除ダイアログ
Future<void> _showWithdrawDialog(BuildContext context) async {
  return showDialog<void>(
    context: context,
    barrierDismissible: false,
    builder: (BuildContext dialogContext) {
      return AlertDialog(
        title: const Text('退会'),
        content: const Text('本当に退会しますか？この操作は取り消せません。'),
        actions: <Widget>[
          TextButton(
            child: const Text('キャンセル'),
            onPressed: () {
              Navigator.of(dialogContext).pop();
            },
          ),
          Consumer(builder: (context, ref, _) {
            final userNotifier = ref.read(userProvider.notifier);

            return TextButton(
              child: const Text('退会する'),
              onPressed: () async {
                userNotifier.deleteUser().then((value) async {
                  final wifiSetupNotifier =
                      ref.read(wifiSetupCheckProvider.notifier);
                  await wifiSetupNotifier.deleteWifiSetupDone();
                  if (context.mounted) Navigator.of(dialogContext).pop();
                  Navigator.pushReplacement(
                      context,
                      MaterialPageRoute(
                          builder: (context) => WithdrawalCompleteScreen()));
                });
              },
            );
          })
        ],
      );
    },
  );
}

// lib/screens/home/withdrawal_complete_screen.dart
import 'package:clocky_app/screens/registration/start_screen.dart';
import 'package:flutter/material.dart';

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

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        automaticallyImplyLeading: false,
        title: const Text('退会完了'),
      ),
      body: Center(
        child: Column(
          mainAxisAlignment: MainAxisAlignment.center,
          children: [
            const Text('退会手続きが完了しました。'),
            const SizedBox(height: 24),
            ElevatedButton(
              onPressed: () => Navigator.pushReplacement(context,
                  MaterialPageRoute(builder: (context) => StartScreen())),
              child: const Text('新規登録へ戻る'),
            ),
          ],
        ),
      ),
    );
  }
}

flutter: apiHeaders: {Content-Type: application/json, Accept: application/json, Authorization: Bearer XXXXXX}
flutter: User delete request sent successfully

clocky_api_local  | Want to delete uid: XXXXXXX
clocky_api_local  | {"time":"2024-05-07T07:27:35.548105276Z","id":"","remote_ip":"192.168.65.1","host":"192.168.XX.XXX:8080","method":"DELETE","uri":"/app/me","user_agent":"Dart/3.3 (dart:io)","status":204,"error":"","latency":1113168250,"latency_human":"1.11316825s","bytes_in":0,"bytes_out":0}