初入koa2 -起步

新手起步可以参考

http://www.jianshu.com/p/6b816c609669

安装完后app.js大概是这样的，其中一些插件是我另外安装的

const Koa = require('koa')
const views = require('koa-views')
const json = require('koa-json')
const onerror = require('koa-onerror')
const bodyparser = require('koa-bodyparser')
const logger = require('koa-logger')
const cors = require('koa2-cors');
const index = require('./routes/index')
const users = require('./routes/users')

const app = new Koa()
// error handler
onerror(app)
//跨域插件
app.use(cors())
// middlewares
app.use(bodyparser({
  enableTypes:['json', 'form', 'text']
}))
app.use(json())
app.use(logger())
//静态文件引用
app.use(require('koa-static')(__dirname + '/public'))
//模板，pug后缀
app.use(views(__dirname + '/views', {
  extension: 'pug'
}))

// logger
app.use(async (ctx, next) => {
  const start = new Date()
  await next()
  const ms = new Date() - start
  console.log(`${ctx.method} ${ctx.url} - ${ms}ms`)
})

// routes
// allowedMethods()当前接口运行的methods
app.use(index.routes(), index.allowedMethods())
app.use(users.routes(), users.allowedMethods())

// error-handling
app.on('error', (err, ctx) => {
  console.error('server error', err, ctx)
});

module.exports = app