nodejs开发微信1——微信路由设置a（access_token和tickets）

 /* jshint -W079 */
 /* jshint -W020 */

 "use strict";
 var _ = require("lodash");
 var sha1 = require('sha1');
 var urlencode = require('urlencode');
 var wurl = require('wurl');
 var request = require('request');
 var express = require('express');
 var router = express.Router();

 module.exports = function(app, domain) {
   var appid="wx75340481908402a8";
   var appsecret = "2b6ee0cbeec0114eb539e68ba356329b";

   /* 微信中继接口 */
   router.get('/wechat/ticket', function (req, res) {
     var page = req.query.page;

     if (page && page.indexOf('from=singlemessage') > 0 && page.indexOf('&isappinstalled=0') < 0) page = page + "&isappinstalled=0";

     WeChatTicket.findOne({appid: appid}).exec(function (err, ticket) {
       if (_.isEmpty(ticket)) { refreshTicket(appid, appsecret, page, null, res); return; }

       var difference = parseInt(new Date().getTime() / 1000) - ticket.at;

       // 如果超时
       if (difference > 7100) refreshTicket(appid, appsecret, page, ticket, res);
       else {
         var json = ticket.toJSON();
         var timestamp = parseInt(new Date().getTime() / 1000);
         json.at = timestamp;
         json.signature = wechatSignature(ticket, page, timestamp);

         res.json({ticket: json});
       }
     });
   });

 // 微信 access_token 接口
 //  3、通过路由获取token，并返回json格式数据;
   router.get('/wechat/access_token', function (req, res) {
     getToken(appid, appsecret, function(token, error) {
       if(error) console.error(error);
       res.json(token);
     });
   });
   //第二步获取token，在数据库中拿出token，如果时间过期重新获取token，如果不过期，使用此token
   function getToken(appid, appsecret, cb) {
     WeChatAccessToken.findOne({appid: appid}, function (err, token) {
       if(token) {
         var difference = parseInt(new Date().getTime() / 1000) - token.at;
         if (difference > 7100) refreshToken(appid, appsecret, function(data, err) { cb(data, err); });
         else cb(token, null);
       } else refreshToken(appid, appsecret, function(data, err) { cb(data, err); });
     });
   }
   //第一步刷新token，此步骤是第一步，通过appid和appsecret就可获得accesstoken;此步骤的作用
   //生成token，此处有个技巧，有token替换，无token，直接生成；
   function refreshToken(appid, appsecret, cb) {
     var access_token_api = "https://api.weixin.qq.com/cgi-bin/token?grant_type=client_credential&appid=APPID&secret=APPSECRET";
     var url = access_token_api.replace('APPID', appid).replace('APPSECRET', appsecret);

     // 参考请求： http://localhost:7000/wechat/ticket?appid=wx8160a61c2d53fb74&appsecret=aa2c953465334823e20090156527a957
     request.get(url, function (error, response, body) {
       if(body) {
         WeChatAccessToken.findOne({appid: appid}, function (err, token) {
           if (!token) token = new WeChatAccessToken();
           var data = JSON.parse(body);

           token.appid = appid;
           token.access_token = data.access_token;
           token.expires_in = data.expires_in;
           token.at = parseInt(new Date().getTime() / 1000);
           token.save(function (err) { cb(token, err); });
         });
       } else cb(null, error);
     });
   }
   //获取ticket第一步;此处用到了getToken的方法；传入appid,appsecrect,
   //首先得到token,拼接获取ticket的url，求情该url得到ticket；将获得的ticket格式化，即body
   //存储到数据库,此处用到了签名的函数wechatSignature();
   function refreshTicket(appid, appsecret, page, ticket, res) {
     getToken(appid, appsecret, function (token, err) {
       if(err !== null) { res.json({error: err}); return; }
       if(_.isEmpty(token.access_token)) { res.json({error: err}); return; }

       // 获取 jsapi_ticket
       var ticket_url = 'https://api.weixin.qq.com/cgi-bin/ticket/getticket?access_token=' + token.access_token + '&type=jsapi';

       request.get(ticket_url, function (error, response, body) {
         var t = ticket === null ? new WeChatTicket() : ticket;
         var data = JSON.parse(body);

         if(!data.ticket) { res.json({error: response}); return; }

         var timestamp = parseInt(new Date().getTime() / 1000);

         t.appid = appid;
         t.ticket = data.ticket;
         t.noncestr = sha1(new Date());
         t.expires_in = data.expires_in;
         t.at = timestamp;

         var signature = wechatSignature(t, page, timestamp);

         t.save(function (err) {
           var json = t.toJSON();
           json.at = timestamp;
           json.signature = signature;
           res.json({ticket: json, error: err});
         });
       });
     });
   }

   /* 微信签名实现 */
   function wechatSignature(t, page, timestamp) {
     var string = "jsapi_ticket=" + t.ticket + "&noncestr=" + t.noncestr + "&timestamp=" + timestamp + "&url=" + page;
     return sha1(string);
   }

   return router;
 };