为什么使用koa2搭建微信第三方公众平台的原因

l.js===== //截获微信返回的xml流文件 const Promise = require('bluebird'); //普通post流转化为promise var Tool = { convertPost: function(req) { let post_data = ""; return new Promise(function(resolve,reject){ req.on('data',function(chunk) { post_data += chunk; });

  req.on('end',function() {
    resolve(post_data);
  });
});

},};
module.exports = Tool;

=====weichat.js======
//微信响应主体文件
const router = require('koa-router')();
const parsemessage = require('../common/parsemessage');
const config = require('../config');
const WXBizMsgCrypt = require('wechat-crypto');
const middleware = require('../model/middleware');
const validator = require('validator');
const Aes = require('../common/aes');
const Tool = require('../common/tool');
const cryptor = new WXBizMsgCrypt(config.component_config.token,config.component_config.key,config.component_config.component_appid);

//第三方授权路径 /:appid/callBACk /wechat/100234/callBACk
router.post('/:appid/callBACk',async function(ctx,next) {
let post_data = "";
let req = ctx.req;
post_data = await Tool.convertPost(req);
let xml = parsemessage(post_data);
let signature = cryptor.getSignature(ctx.query.timestamp,ctx.query.nonce,xml.encrypt);
if (ctx.query.msg_signature != signaturE) {
ctx.body = 'Auth failed!'; // 指纹码不匹配时返回错误信息，禁止后面的消息接受及发送
}
let message = middleware.decryptXml(xml);
let appid = ctx.params.appid;
message.appId = appid;
//发送消息队列
switch (message.msgTypE) {
case 'text':
//测试
if (message.toUserName == "gh_3c884a361561") {
if (message.content == "TESTCOMPONENT_MSG_TYPE_TEXT") {
let text = middleware.text(message,message.content + "_callBACk");
let reply = middleware.encryptXml(text);
return ctx.body = reply;
}
let content = message.content;
if (content.indexOf("QUERY_AUTH_CODE") != -1) {
ctx.body = "";
let code_li = content.split(":");
await middleware.customSend(message.fromUserName,code_lI[1]);
return;
}
}
let keywords = validator.trim(message.content).toLowerCase();
let member_config = await middleware.getMemberConfig(message.toUserName,keywords);
if (!member_config) {
await middleware.sendMnsQuene(messagE);
return ctx.body = "success";
}else{
//匹配成功
message.packetsId = parseInt(member_config.hongbaoId);
message.keywords = keywords;
await middleware.sendMnsQuene(messagE);

    let data = {
      title: member_config.news_title || '点我领红包',description: member_config.description || '第一轮红包雨开始了,手快有,手慢无！',picurl: member_config.picurl || 'http://7xqomp.com2.z0.glb.qiniucdn.com/17269743.png'
    };
    let key = {
      fromUserName: message.fromUserName,toUserName: message.toUserName,keywords: keywords,appId: appid
    };
    key = JSON.Stringify(key);
    key = Aes.encypt(key);
    key = Aes.base64_encode(key);

    //获取授权域名
    let auth_url = await middleware.packetDomain();
    data.url = "http://" + appid + "." + auth_url + "/redPackets/koulin?key=" + key;
    let news = middleware.news(message,[data]);
    let reply = middleware.encryptXml(news);
    ctx.body = reply; 
    return;       
  }
  break;
case 'event':
  await middleware.sendMnsQuene(messagE);
  //测试专用
  if (message.toUserName == "gh_3c884a361561") {
    let text = middleware.text(message,message.event + "from_callBACk");
    let reply = middleware.encryptXml(text);
    ctx.body = reply;
    return;
  }
  break;
default:
  await middleware.sendMnsQuene(messagE);
  ctx.body = "success";
  return;

};
});
module.exports = router;