moa.js

const http = require('http')

const context = require('./context')
const request = require('./request')
const response = require('./response')

class Moa {
  constructor() {
    this.middlewares = []
  }

  use(middleware) {
    this.middlewares.push(middleware)
  }
  listen(...args) {
    const server = http.createServer(async (req, res) => {
      // 创建上下文
      const ctx = this.createContext(req, res)
      const fn = this.compose(this.middlewares)
      await fn(ctx)
      // 响应
      res.end(ctx.body)
    })

    server.listen(...args)
  }

  createContext(req, res) {
    const ctx = Object.create(context)
    ctx.request = Object.create(request)
    ctx.response = Object.create(response)

    ctx.req = ctx.request.req = req
    ctx.res = ctx.response.res = res
    return ctx
  }

  compose(middlewares) {
    return function (ctx) {
      return dispatch(0)
      function dispatch(i) {
        let fn = middlewares[i]
        if (!fn) {
          return Promise.resolve()
        }
        return Promise.resolve(
          fn(ctx, function () {
            return dispatch(i + 1)
          })
        )
      }
    }
  }
}

module.exports = Moa