# koa2 原生路由实现
# 简单例子
const Koa = require('koa')
const app = new Koa()
app.use( async ( ctx ) => {
let url = ctx.request.url
ctx.body = url
})
app.listen(3000)
访问 http://localhost:3000/hello/world 页面会输出 /hello/world，也就是说上下文的请求request对象中url之就是当前访问的路径名称，可以根据ctx.request.url 通过一定的判断或者正则匹配就可以定制出所需要的路由。
# 定制化的路由
demo源码
https://github.com/poetries/daily-code-practice/tree/master/node/koa/koa2-demo/route-simple
# 源码文件目录
.
├── index.js
├── package.json
└── view
├── 404.html
├── index.html
└── todo.html
# demo源码
const Koa = require('koa')
const fs = require('fs')
const app = new Koa()
/**
* 用Promise封装异步读取文件方法
* @param {string} page html文件名称
* @return {promise}
*/
function render( page ) {
return new Promise(( resolve, reject ) => {
let viewUrl = `./view/${page}`
fs.readFile(viewUrl, "binary", ( err, data ) => {
if ( err ) {
reject( err )
} else {
resolve( data )
}
})
})
}
/**
* 根据URL获取HTML内容
* @param {string} url koa2上下文的url，ctx.url
* @return {string} 获取HTML文件内容
*/
async function route( url ) {
let view = '404.html'
switch ( url ) {
case '/':
view = 'index.html'
break
case '/index':
view = 'index.html'
break
case '/todo':
view = 'todo.html'
break
case '/404':
view = '404.html'
break
default:
break
}
let html = await render( view )
return html
}
app.use( async ( ctx ) => {
let url = ctx.request.url
let html = await route( url )
ctx.body = html
})
app.listen(3000)
console.log('[demo] route-simple is starting at port 3000')
# 运行demo
# 执行运行脚本
node -harmony index.js
