如何在loopback 4中返回客户端IP地址？

npm install @loopback/middleware

import { RestApplication, RestServer, RestBindings } from '@loopback/rest';
import { ExpressRequestHandler } from '@loopback/middleware';

export class MyApp extends RestApplication {
  constructor() {
    super();
    this.setupMiddleware();
  }

  setupMiddleware() {
    const expressApp = this.getSync<RestServer>(RestBindings.SERVER).expressApp;
    const requestHandler: ExpressRequestHandler = (req, res, next) => {
      // 获取客户端IP地址
      const clientIp = req.ip;
      // 将客户端IP地址保存到请求上下文中
      req['clientIp'] = clientIp;
      next();
    };
    // 注册中间件
    expressApp.use(requestHandler);
  }
}

import { get, Request } from '@loopback/rest';

export class MyController {
  @get('/example')
  example(req: Request) {
    // 获取客户端IP地址
    const clientIp = req['clientIp'];
    // 处理业务逻辑
    // ...
    return { clientIp };
  }
}