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;
};