Hotwire Native에서 Flutter로 — Rails 앱의 모바일 네이티브 전환 실전기

// iOS Bridge — NotificationTokenComponent.swift
class NotificationTokenComponent: BridgeComponent {
    override class var name: String { "notification-token" }
    
    override func onReceive(message: Message) {
        // 웹에서 "connect" 이벤트 → APNs 토큰 전달
        let token = UserDefaults.standard.string(forKey: "apns_token")
        reply(to: "connect", with: ["token": token, "granted": true])
    }
}

# Gemfile
gem "jwt"

# app/services/jwt_service.rb
class JwtService
  ALGORITHM = "HS256"

  def self.encode(user)
    payload = {
      sub: user.id,
      email: user.email,
      role: user.role,
      exp: 1.hour.from_now.to_i,
      iat: Time.current.to_i
    }
    JWT.encode(payload, Rails.application.secret_key_base, ALGORITHM)
  end

  def self.decode(token)
    JWT.decode(token, Rails.application.secret_key_base, true, algorithm: ALGORITHM).first
  end
end

module Api
  module V1
    class BaseController < ActionController::API
      before_action :authenticate_jwt!

      private

      def authenticate_jwt!
        token = request.headers["Authorization"]&.split(" ")&.last
        return render_unauthorized unless token

        payload = JwtService.decode(token)
        @current_user = User.find(payload["sub"])
      rescue JWT::ExpiredSignature
        render_unauthorized("Token expired")
      rescue JWT::DecodeError, ActiveRecord::RecordNotFound
        render_unauthorized
      end

      def render_unauthorized(msg = "Unauthorized")
        render json: { error: msg }, status: :unauthorized
      end
    end
  end
end

# 잘못된 코드 — 존재하지 않는 메서드
verification = EmailVerificationCode.latest_for(user.email, purpose: "login")
verification.verify!(code)

# 올바른 코드 — 기존 scope 활용
verification = EmailVerificationCode.valid_for(user.email, "login").first
result = verification.verify!(code)

class AuthInterceptor extends Interceptor {
  final Dio _dio;
  final Ref _ref;
  bool _isRefreshing = false;

  @override
  void onRequest(RequestOptions options, RequestInterceptorHandler handler) async {
    // 공개 엔드포인트는 토큰 생략
    final publicPaths = ['/api/v1/auth/sign_in', '/api/v1/auth/verify_otp'];
    if (publicPaths.contains(options.path)) return handler.next(options);

    final token = await _ref.read(authServiceProvider).getAccessToken();
    if (token != null) {
      options.headers['Authorization'] = 'Bearer $token';
    }
    handler.next(options);
  }

  @override
  void onError(DioException err, ErrorInterceptorHandler handler) async {
    if (err.response?.statusCode != 401 || _isRefreshing) {
      return handler.next(err);
    }

    _isRefreshing = true;
    try {
      // refresh token으로 새 access token 발급
      final refreshToken = await _ref.read(authServiceProvider).getRefreshToken();
      final response = await _dio.post('/api/v1/auth/refresh',
        data: {'refresh_token': refreshToken});

      final newToken = response.data['access_token'];
      await _ref.read(authServiceProvider).saveAccessToken(newToken);

      // 원래 요청 재시도
      final opts = err.requestOptions;
      opts.headers['Authorization'] = 'Bearer $newToken';
      handler.resolve(await _dio.fetch(opts));
    } catch (_) {
      await _ref.read(authServiceProvider).clearTokens();
      handler.next(err);
    } finally {
      _isRefreshing = false;
    }
  }
}

# app/controllers/api/v1/messages_controller.rb
def create
  conversation = current_user.conversations.find(params[:conversation_id])
  user_message = conversation.messages.create!(
    role: "user", content: params[:content], status: "done"
  )

  if request.headers["Accept"]&.include?("text/event-stream")
    # SSE 스트리밍 응답
    assistant_message = conversation.messages.create!(
      role: "assistant", content: "", status: "streaming"
    )

    response.headers["Content-Type"] = "text/event-stream"
    response.headers["Cache-Control"] = "no-cache"

    self.response_body = Enumerator.new do |yielder|
      AiService.stream_response(conversation) do |chunk|
        assistant_message.update_columns(
          content: assistant_message.content + chunk
        )
        yielder << "event: chunk\ndata: #{
          { content: chunk, done: false }.to_json
        }\n\n"
      end

      assistant_message.update!(status: "done")
      yielder << "event: done\ndata: #{
        { message_id: assistant_message.id, done: true }.to_json
      }\n\n"
    end
  end
end

# 수정 전 — 에러 발생
validates :content, presence: true  # 빈 문자열이면 validation 실패

# 수정 후 — 스트리밍 assistant만 예외 허용
validates :content, presence: true, unless: :streaming_assistant?

def streaming_assistant?
  role == "assistant" && status == "streaming"
end

Stream<String> sendMessageStream(int conversationId, String content) async* {
  final response = await _dio.post(
    '/api/v1/conversations/$conversationId/messages',
    data: {'content': content},
    options: Options(
      responseType: ResponseType.stream,
      headers: {'Accept': 'text/event-stream'},
    ),
  );

  final stream = response.data.stream as Stream<List<int>>;
  String buffer = '';

  await for (final chunk in stream) {
    buffer += utf8.decode(chunk);

    while (buffer.contains('\n\n')) {
      final eventEnd = buffer.indexOf('\n\n');
      final eventBlock = buffer.substring(0, eventEnd);
      buffer = buffer.substring(eventEnd + 2);

      for (final line in eventBlock.split('\n')) {
        if (line.startsWith('data: ')) {
          final data = jsonDecode(line.substring(6));
          if (data['done'] == true) return;
          yield data['content'] as String;
        }
      }
    }
  }
}

// lib/firebase_options.dart
class DefaultFirebaseOptions {
  static FirebaseOptions get currentPlatform {
    switch (defaultTargetPlatform) {
      case TargetPlatform.android:
        return android;
      case TargetPlatform.iOS:
        return ios;
      default:
        throw UnsupportedError('Platform not supported');
    }
  }

  static const FirebaseOptions ios = FirebaseOptions(
    apiKey: 'AIzaSy...',
    appId: '1:981186249046:ios:...',
    messagingSenderId: '981186249046',
    projectId: 'my-project',
    iosBundleId: 'com.example.app',
  );
  // ...
}

# 미추적 파일 중 프로덕션 필수 파일 확인
git status --porcelain | grep "^??" | grep -E "model|concern|service|controller"

# 잘못됨
DEFAULT_MODEL = "bizrouter/claude-sonnet-4-6"

# 올바름
DEFAULT_MODEL = "anthropic/claude-sonnet-4"