upgrade version 2.0,add login api,upgrade api verison,add document and unit test

router/playlistDetail.js

@@ -0,0 +1,68 @@
+const http = require('http')
+const express = require("express")
+const router = express()
+const { createWebAPIRequest } = require("../util/util")
+
+router.get("/", (req, res) => {
+  const cookie = req.get('Cookie') ? req.get('Cookie') : ''
+  let detail, imgurl
+  const data = {
+    "id": req.query.id,
+    "offset": 0,
+    "total": true,
+    "limit": 1000,
+    "n": 1000,
+    "csrf_token": ""
+  }
+
+  createWebAPIRequest(
+    'music.163.com',
+    '/weapi/v3/playlist/detail',
+    'POST',
+    data,
+    cookie,
+     music_req=> {
+      console.log(music_req)
+      detail = music_req
+      mergeRes()
+    },
+     err =>{
+      res.status(502).send('fetch error')
+    }
+  )
+
+  // FIXME:i dont know the api to get coverimgurl
+  // so i get it by parsing html
+  const http_client = http.get({
+    hostname: 'music.163.com',
+    path: '/playlist?id=' + req.query.id,
+    headers: {
+      'Referer': 'http://music.163.com',
+    },
+  }, function (res) {
+    res.setEncoding('utf8')
+    let html = ''
+    res.on('data', function (chunk) {
+      html += chunk
+    })
+    res.on('end', function () {
+      console.log('end', html)
+      const regImgCover = /\<img src=\"(.*)\" class="j-img"/ig
+      imgurl = regImgCover.exec(html)[1]
+      mergeRes()
+
+    })
+  })
+
+  function mergeRes() {
+    if (imgurl != undefined && detail != undefined) {
+      detail = JSON.parse(detail)
+      detail.playlist.picUrl = imgurl
+      res.send(detail)
+    }
+  }
+})
+
+
+
+module.exports = router