如何在顶层单次传入fastify instance供控制器内所有方法使用

方案1：控制器类注入（最适合复杂控制器、有复用需求的场景） #

把控制器改成类，在实例化的时候一次性传入fastify实例，所有类方法都可以通过实例属性访问fastify，不需要每个方法单独传参。

控制器文件修改 #

import { FastifyInstance, FastifyRequest, FastifyReply } from 'fastify'

export default class RootController {
  private fastify: FastifyInstance

  constructor(fastify: FastifyInstance) {
    this.fastify = fastify
  }

  async index(request: FastifyRequest, reply: FastifyReply) {
    const hugs = this.fastify.someSupport()
    reply.send({ status: 'ok', love: hugs })
  }

  async show(request: FastifyRequest, reply: FastifyReply) {
    const hugs = 'extra ' + this.fastify.someSupport()
    reply.send({ status: 'ok', love: hugs })
  }
}

路由文件修改 #

import { FastifyPluginAsync } from 'fastify'
import RootController from '../root.controller'

const root: FastifyPluginAsync = async (fastify, opts): Promise<void> => {
  // 仅此处实例化一次，传入fastify
  const controller = new RootController(fastify)
  fastify.get('/', controller.index.bind(controller))
  fastify.get('/show', controller.show.bind(controller))
}

export default root

方案2：闭包工厂函数（适合轻量控制器、不想用类的场景） #

写一个工厂函数，接收fastify后返回包含所有控制器方法的对象，所有方法通过闭包共享同一个fastify实例。

控制器文件修改 #

import { FastifyInstance, FastifyRequest, FastifyReply } from 'fastify'

export default function createRootController(fastify: FastifyInstance) {
  return {
    async index(request: FastifyRequest, reply: FastifyReply) {
      const hugs = fastify.someSupport()
      reply.send({ status: 'ok', love: hugs })
    },
    async show(request: FastifyRequest, reply: FastifyReply) {
      const hugs = 'extra ' + fastify.someSupport()
      reply.send({ status: 'ok', love: hugs })
    }
  }
}

路由文件修改 #

import { FastifyPluginAsync } from 'fastify'
import createRootController from '../root.controller'

const root: FastifyPluginAsync = async (fastify, opts): Promise<void> => {
  // 仅此处调用一次工厂函数，传入fastify
  const controller = createRootController(fastify)
  fastify.get('/', controller.index)
  fastify.get('/show', controller.show)
}

export default root

方案3：直接从请求对象获取（零注入成本，最省事） #

Fastify 原生在每个请求对象上挂载了server属性，就是当前的Fastify实例，不需要主动传递，直接在控制器里访问即可。

控制器文件修改 #

import { FastifyRequest, FastifyReply } from 'fastify'

export default {
  async index(request: FastifyRequest, reply: FastifyReply) {
    const hugs = request.server.someSupport()
    reply.send({ status: 'ok', love: hugs })
  },

  async show(request: FastifyRequest, reply: FastifyReply) {
    const hugs = 'extra ' + request.server.someSupport()
    reply.send({ status: 'ok', love: hugs })
  }
}

路由文件修改 #

import { FastifyPluginAsync } from 'fastify'
import RootController from '../root.controller'

const root: FastifyPluginAsync = async (fastify, opts): Promise<void> => {
  // 不需要传递fastify，直接注册方法即可
  fastify.get('/', RootController.index)
  fastify.get('/show', RootController.show)
}

export default root

不同方案适用场景：

• 方案3适合绝大多数简单场景，不需要修改注入逻辑，代码量最小
• 方案2适合偏好函数式编程、不需要类特性的场景
• 方案1适合控制器逻辑复杂、需要继承/混入、或者有多处复用控制器逻辑的场景

内容的提问来源于stack exchange，提问作者mybigman