Middleware Patterns

NestJS middleware used for request processing.

Overview

Middleware executes before route handlers and guards. Gauzy uses middleware for:

• Request logging
• CORS configuration
• Request context setup
• Rate limiting
• Request body parsing

Global Middleware

// main.ts
app.use(helmet());
app.use(compression());
app.enableCors({
  origin: process.env.CLIENT_BASE_URL,
  credentials: true,
});

Request Logging Middleware

@Injectable()
export class RequestLoggerMiddleware implements NestMiddleware {
  use(req: Request, res: Response, next: NextFunction) {
    const start = Date.now();
    res.on("finish", () => {
      const duration = Date.now() - start;
      console.log(`${req.method} ${req.url} ${res.statusCode} ${duration}ms`);
    });
    next();
  }
}

Request Context Middleware

Sets up tenant and user context for each request:

@Injectable()
export class RequestContextMiddleware implements NestMiddleware {
  use(req: Request, res: Response, next: NextFunction) {
    const requestContext = new RequestContext(req, res);
    RequestContext.setCurrentContext(requestContext);
    next();
  }
}

Applying Middleware

@Module({})
export class AppModule implements NestModule {
  configure(consumer: MiddlewareConsumer) {
    consumer
      .apply(RequestLoggerMiddleware, RequestContextMiddleware)
      .forRoutes("*");
  }
}

Middleware vs Guards vs Interceptors

Component	Executes	Access To	Use Case
Middleware	Before all	req, res, next	Logging, CORS
Guards	After middleware	ExecutionContext	Auth, permissions
Interceptors	Around handler	CallHandler	Transform, cache

Related Pages

• Request Lifecycle — full flow
• Guard System — guards
• Interceptor Patterns — interceptors