NestJS(Fastify)中间件中Cookie相关对象为undefined的问题求助

使用的技术版本 #

• NestJS CLI: 9.0.0
• NestJS Common & NestJS Platform Fastify: 9.0.11
• Fastify: 4.4.0
• @fastify/cookie: 8.0.0

问题描述 #

在中间件中尝试读取和设置Cookie时，发现request.cookies、response.setCookie、response.cookie均为undefined，但在控制器中这些对象和方法却能正常访问。

中间件代码 #

this.logger.debug("cookies", request.cookies)
this.logger.debug("setCookie", response.setCookie)
this.logger.debug("cookie", response.cookie)

中间件日志输出 #

DEBUG [DeviceMiddleware] cookies
DEBUG [DeviceMiddleware] undefined
DEBUG [DeviceMiddleware] setCookie
DEBUG [DeviceMiddleware] undefined
DEBUG [DeviceMiddleware] cookie
DEBUG [DeviceMiddleware] undefined

控制器日志输出 #

DEBUG [AppController] cookies
DEBUG [AppController] Object:
{}
DEBUG [AppController] setCookie
DEBUG [AppController] function setCookie (name, value, cookieOptions) {
  const opts = Object.assign({}, options.parseOptions, cookieOptions)
  return fastifyCookieSetCookie(this, name, value, opts, signer)
}
DEBUG [AppController] cookie
DEBUG [AppController] function setCookie (name, value, cookieOptions) {
  const opts = Object.assign({}, options.parseOptions, cookieOptions)
  return fastifyCookieSetCookie(this, name, value, opts, signer)
}

原因分析与解决方法 #

核心原因是@fastify/cookie插件的注册时机晚于中间件，导致中间件执行时，Fastify还未完成Cookie相关的请求/响应对象增强。

解决步骤 #

1. 提前注册Cookie插件：在main.ts中先注册@fastify/cookie，再挂载中间件，确保插件逻辑先于中间件执行：

import { NestFactory } from '@nestjs/core';
import { FastifyAdapter, NestFastifyApplication } from '@nestjs/platform-fastify';
import fastifyCookie from '@fastify/cookie';
import { AppModule } from './app.module';
import { DeviceMiddleware } from './middleware/device.middleware';

async function bootstrap() {
  const app = await NestFactory.create<NestFastifyApplication>(
    AppModule,
    new FastifyAdapter(),
  );
  // 优先注册cookie插件
  await app.register(fastifyCookie);
  // 再注册中间件
  app.use(new DeviceMiddleware().use);
  await app.listen(3000);
}
bootstrap();

2. 替换为拦截器：若中间件注册顺序无法调整，可改用NestJS拦截器。拦截器的执行时机晚于Fastify插件注册，能正常访问Cookie相关方法。

内容的提问来源于stack exchange，提问作者armada45