Koa注解

Koa注解

Node 支持装饰者模式

1. 添加 babel 需要的 npm 包

   javascript
   yarn add @babel/core @babel/preset-env @babel/plugin-proposal-decorators @babel/polyfill @babel/register -D
   

2. 新建 .babelrc 配置文件

   javascript
   {
       "presets": [
           "@babel/preset-env"
       ],
       "plugins": [
           [
               "@babel/plugin-proposal-decorators",
               {
                   "legacy": true
               }
           ]
       ]
   }
   

3. Node 前置执行 垫片代码

   javascript
   require('@babel/register')()
   require('@babel/polyfill')
   
   const app = new Koa();
   app.use(async (ctx,next)=>{
   	ctx.body = {
   		code:0
   	}
   })
   const port = process.env.PORT || 3000;
   
   app.listen(port, () => {
       console.log(`app started on: ${port}`)
   })
   

此时 项目中可以使用装饰者注解@ 方式来操作了。

注解方式处理路由

1. 添加 koa 相关依赖

javascript
yarn add glob koa koa-router 

1. 统一处理 koa 路由

   javascript
   const path = require("path");
   const Router = require("koa-router");
   const glob = require("glob");
   
   const symbolPrefix = Symbol('prefix');
   
   //注解方法集合
   const routerMap = new Map();
   const isArray = obj => Array.isArray(obj) ? obj : [obj];
   //注解方法集合
   const methods = { POST: null, GET: null, PUT: null, DEL: null, ALL: null, OPTIONS: null, HEAD: null, PATCH: null };
   
   //格式化路径
   const formatPath = path => {
       path = path.url || path;
       return path === '/' ?
           '' :
           path.startsWith('/') ?
               path :
               `/${path}`
   }
   
   //注解方法汇总
   const loadRouter = conf => (target, name, descriptor) => {
       conf.path = formatPath(conf.path);
       routerMap.set({
           target,
           ...conf
       }, target[name])
   
       //如果是 / 路径
       if (conf.path === '/') {
           conf.path = "";
           routerMap.set({
               target,
               ...conf
           }, target[name])
       }
   }
   
   //注解方法加载
   Object.keys(methods).forEach((key) => {
       methods[key] = (path) => {
           return loadRouter({
               method: key.toLowerCase(),
               path
           })
       }
   })
   
   
   //注解 Controller
   const Controller = (path) => {
       return target => {
           target.prototype[symbolPrefix] = path
       }
   }
   
   const Validate = (...mids) => {
       return (...args) => {
           const [target, name, descriptor] = args
           target[name] = isArray(target[name])
           target[name].unshift(...mids)
           return descriptor
       }
   }
   
   class Route {
       constructor(app, apiPath) {
           this.app = app
           this.apiPath = apiPath
           this.router = new Router()
       }
   
       init() {
           // 将 api 文件接口全部同步载入
           glob.sync(path.resolve(this.apiPath, './*.ts')).forEach(require)
           glob.sync(path.resolve(this.apiPath, './*.js')).forEach(require)
   
           for (let [conf, controller] of routerMap) {
               const controllers = isArray(controller)
               const prefixPath = conf.target[symbolPrefix] ? formatPath(conf.target[symbolPrefix]) : ''
               const routerPath = prefixPath + conf.path
               this.router[conf.method](routerPath, ...controllers)
           }
   
           this.app.use(this.router.routes())
           this.app.use(this.router.allowedMethods())
       }
   }
   
   // 解构所有的注解方法
   const { POST, GET, PUT, DEL, ALL, OPTIONS, HEAD, PATCH } = methods;
   
   module.exports = {
       Controller,
       Route,
       POST, GET, PUT, DEL, ALL, OPTIONS, HEAD, PATCH,
       Validate
   }
   
   

2. 项目使用decorator

   javascript
   require('@babel/register')()
   require('@babel/polyfill')
   
   const Koa = require("koa");
   const path = require("path");
   const { Route } = require('./utils/decorator');
   
   const app = new Koa();
   
   //路由处理
   const apiPath = path.resolve(__dirname, './controller')
   new Route(app, apiPath).init();
   
   const port = process.env.PORT || 3000;
   
   app.listen(port, () => {
       console.log(`app started on: ${port}`)
   })
   
   

3. 路由注解使用

   javascript
   // /src/controller/CommonController.js
   
   const { Controller, GET, POST, Validate } = require('../utils/decorator');
   
   @Controller("/")
   export class CommonController {
   
       @GET("/")
       async home(ctx, next) {
           ctx.body = {
               message:"home"
           }
       }
   
       @GET('/test')
       async test(ctx, next) {
           ctx.body = {
               message:"测试"
           }
       }
   }