fastify-request-context fastify request 级别的存储支持扩展

fastify-request-context 是一个fastify插件基于nodejs 的async hooks 的处理，比较方便，尤其我们是需要进行基于request 进行一些扩展的时候
实际上不少框架都类似类似的能力（比如java web 框架的httpServletSession, sparkjava 的request attribute）

参考使用

注册以及使用

 
const { fastifyRequestContextPlugin, requestContext } = require('@fastify/request-context')

const fastify = require('fastify');
 
const app = fastify({ logger: true })

// 注册插件

app.register(fastifyRequestContextPlugin, { 

  defaultStoreValues: {

    user: { id: 'system' } 

  }

});

// 进行request 数据设置

app.addHook('onRequest', (req, reply, done) => {

  // Overwrite the defaults.

  // This is completely equivalent to using app.requestContext or just requestContext 

  req.requestContext.set('user', { id: 'helloUser' });

  done();

});
 
// this should now get `helloUser` instead of the default `system`

app.get('/', (req, reply) => {

// 获取request context 数据

  // requestContext singleton exposed by the library retains same request-scoped values that were set using `req.requestContext`

  const user = requestContext.get('user');

  reply.code(200).send( { user });

});
 
app.get('/decorator', function (req, reply) {

// 获取request context 数据

  // requestContext singleton exposed as decorator in the fastify instance and can be retrieved:

  const user = this.requestContext.get('user'); // using `this` thanks to the handler function binding

  const theSameUser = app.requestContext.get('user'); // directly using the `app` instance

  reply.code(200).send( { user });

});
 
app.listen({ port: 3000 }, (err, address) => {

  if (err) throw err

  app.log.info(`server listening on ${address}`)

});
 
return app.ready()