// /config/wechat.cfg.js
module.exports = {
    grant_type: 'client_credential',
    appid: 'xxxxxxxxxxxxxxx',
    secret: 'xxxxxxxxxxxxxxxxxxxxxxxxxx',
    accessTokenUrl:'https://api.weixin.qq.com/cgi-bin/token',
    ticketUrl:'https://api.weixin.qq.com/cgi-bin/ticket/getticket',
    cache_duration:1000*60*60*2 //根据规定缓存时长为2小时
}

// signature.js
var request = require('request'),
    cache = require('memory-cache'),
    sha1 = require('sha1'),
    config = require('./config/wechat.cfg');

exports.sign = function (url,callback) {
    var noncestr = Math.random().toString(36).substr(2, 15),
        timestamp = Math.floor(Date.now()/1000), //精确到秒
        jsapi_ticket;
    if(cache.get('ticket')){
        jsapi_ticket = cache.get('ticket');
        console.log('1' + 'jsapi_ticket=' + jsapi_ticket + '&noncestr=' + noncestr + '&timestamp=' + timestamp + '&url=' + url);
        callback({
            noncestr:noncestr,
            timestamp:timestamp,
            url:url,
            jsapi_ticket:jsapi_ticket,
            signature:sha1('jsapi_ticket=' + jsapi_ticket + '&noncestr=' + noncestr + '&timestamp=' + timestamp + '&url=' + url)
        });
    }else{
        request(config.accessTokenUrl + '?grant_type=' + config.grant_type + '&appid=' + config.appid + '&secret=' + config.secret ,function(error, response, body){
            if (!error && response.statusCode == 200) {
                var tokenMap = JSON.parse(body);
                request(config.ticketUrl + '?access_token=' + tokenMap.access_token + '&type=jsapi', function(error, resp, json){
                    if (!error && response.statusCode == 200) {
                        var ticketMap = JSON.parse(json);
                        cache.put('ticket',ticketMap.ticket,config.cache_duration);  //加入缓存
                        console.log('jsapi_ticket=' + ticketMap.ticket + '&noncestr=' + noncestr + '&timestamp=' + timestamp + '&url=' + url);
                        callback({
                            noncestr:noncestr,
                            timestamp:timestamp,
                            url:url,
                            jsapi_ticket:ticketMap.ticket,
                            signature:sha1('jsapi_ticket=' + ticketMap.ticket + '&noncestr=' + noncestr + '&timestamp=' + timestamp + '&url=' + url)
                        });
                    }
                })
            }
        })
    }
}

// server.js
//引入配置和方法
var express = require('express')
var signature = require('./signature'); 
var wechat_cfg = require('./config/wechat.cfg');

var server = express();

.........(省略代码)
//增加一条api供客户端使用
server.get("/api/signature", function(req,res) {
  const url = req.query.url.split('#')[0];
  signature.sign(url,function(signatureMap){
    //因为config接口需要appid,多加一个参数传入appid
    signatureMap.appId = wechat_cfg.appid;
    //发送给客户端
    res.send(signatureMap);
  });
})
.........(省略代码)

//增加一条api供客户端使用
router.get("/api/signature", function *(next) {
  const url = this.request.query.url.split('#')[0];
  console.log(url);
  signature.sign(url,function(signatureMap){
    //因为config接口需要appid,多加一个参数传入appid
    signatureMap.appId = wechat_cfg.appid;
    //发送给客户端
   this.body = signatureMap;  //这一行会出错,估计this对象已经不一样了!通过外层传递this变量也是不行
  });
})

app.use(function *(){
    this.demo = 'test text';
});

app.use(function *(){
    this.body = this.demo;
});

app.use(function *(next){
    this.demo = 'test text';
   yield next;
});

app.use(function *(){
    this.body = this.demo;
});

class Polygon{
  constructor(height, width){
      this.height = height;
      this.width = width;
  }
  get name(){
      return this.name;
  }
  set name(somename){
      this.name = somename;
  }
}