"dependencies": {

    "crypto": "^1.0.1",

    "express": "^4.16.3",

    "request": "^2.85.0",

    "xmlreader": "^0.2.3"

  }

var xmlreader = require("xmlreader");

var fs = require("fs");

var wxpay = {

    //把金额转为分

    getmoney: function (money) {

        return parseFloat(money) * 100;

    },

    // 随机字符串产生函数

    createNonceStr: function () {

        return Math.random().toString(36).substr(2, 15);

    },

    // 时间戳产生函数

    createTimeStamp: function () {

        return parseInt(new Date().getTime() / 1000) + '';

    },

    //签名加密算法

    paysignjsapi: function (appid, body, mch_id, nonce_str, notify_url, out_trade_no, spbill_create_ip, total_fee, trade_type, mchkey) {

        var ret = {

            appid: appid,

            mch_id: mch_id,

            nonce_str: nonce_str,

            body: body,

            notify_url: notify_url,

            out_trade_no: out_trade_no,

            spbill_create_ip: spbill_create_ip,

            total_fee: total_fee,

            trade_type: trade_type

        };

        console.log('ret==', ret);

        var string = raw(ret);

        var key = mchkey;

        string = string + '&key=' + key;

        console.log('string=', string);

        var crypto = require('crypto');

        return crypto.createHash('md5').update(string, 'utf8').digest('hex').toUpperCase();

    },

    //签名加密算法,第二次的签名

    paysignjsapifinal: function (appid,mch_id,prepayid,noncestr,timestamp,mchkey) {

        var ret = {

            appid: appid,

            partnerid: mch_id,

            prepayid: prepayid,

            package: 'Sign=WXPay',

            noncestr: noncestr,

            timestamp: timestamp,

        };

        console.log('retretret==', ret);

        var string = raw(ret);

        var key = mchkey;

        string = string + '&key=' + key;

        console.log('stringstringstring=', string);

        var crypto = require('crypto');

        return crypto.createHash('md5').update(string, 'utf8').digest('hex').toUpperCase();

    },

    getXMLNodeValue: function (xml) {

        // var tmp = xml.split("<"+node_name+">");

        // console.log('tmp',tmp);

        // var _tmp = tmp[1].split("</"+node_name+">");

        // console.log('_tmp',_tmp);

        // return _tmp[0];

        xmlreader.read(xml, function (errors, response) {

            if (null !== errors) {

                console.log(errors)

                return;

            }

            console.log('长度===', response.xml.prepay_id.text().length);

            var prepay_id = response.xml.prepay_id.text();

            console.log('解析后的prepay_id==',prepay_id);

            return prepay_id;

        });

    }

}

function raw(args) {

    var keys = Object.keys(args);

    keys = keys.sort()

    var newArgs = {};

    keys.forEach(function (key) {

        newArgs[key] = args[key];

    });

    var string = '';

    for (var k in newArgs) {

        string += '&' + k + '=' + newArgs[k];

    }

    string = string.substr(1);

    return string;

}

module.exports = wxpay;

var express = require('express');

var request = require('request');

var xmlreader = require("xmlreader");

var fs = require("fs");

var app = express();

var wxpay = require('./util');

var appid     = '';　　

var appsecret = '';

var mchid     = ''

var mchkey    = '';

var wxurl     = 'http://xxxx';

app.get('/',(req,res)=>{

    //首先拿到前端传过来的参数

    let orderCode = 20150806125346;

    let money     = 100;

    let orderID   = 1;

    // console.log('APP传过来的参数是',orderCode+'----'+money+'------'+orderID+'----'+appid+'-----'+appsecret+'-----'+mchid+'-----'+mchkey);

    //首先生成签名sign

    appid

    let mch_id = mchid;

    let nonce_str = wxpay.createNonceStr();

    let timestamp = wxpay.createTimeStamp();

    let body = '测试微信支付';

    let out_trade_no = orderCode;

    let total_fee = wxpay.getmoney(money);

    let spbill_create_ip = req.connection.remoteAddress;

    let notify_url = wxurl;

    let trade_type = 'JSAPI';

    let sign = wxpay.paysignjsapi(appid,body,mch_id,nonce_str,notify_url,out_trade_no,spbill_create_ip,total_fee,trade_type,mchkey);

    console.log('sign==',sign);

    //组装xml数据

    var formData  = "<xml>";

    formData  += "<appid>"+appid+"</appid>";  //appid

    formData  += "<body><![CDATA["+"测试微信支付"+"]]></body>";

    formData  += "<mch_id>"+mch_id+"</mch_id>";  //商户号

    formData  += "<nonce_str>"+nonce_str+"</nonce_str>"; //随机字符串，不长于32位。

    formData  += "<notify_url>"+notify_url+"</notify_url>";

    formData  += "<out_trade_no>"+out_trade_no+"</out_trade_no>";

    formData  += "<spbill_create_ip>"+spbill_create_ip+"</spbill_create_ip>";

    formData  += "<total_fee>"+total_fee+"</total_fee>";

    formData  += "<trade_type>"+trade_type+"</trade_type>";

    formData  += "<sign>"+sign+"</sign>";

    formData  += "</xml>";

    // console.log('formData===',formData);

    var url = 'https://api.mch.weixin.qq.com/pay/unifiedorder';

    request({url:url,method:'POST',body: formData},function(err,response,body){

        if(!err && response.statusCode == 200){

            // console.log(body);

            xmlreader.read(body.toString("utf-8"), function (errors, response) {

                if (null !== errors) {

                    // console.log(errors)

                    return;

                }

                // console.log('长度===', response.xml.prepay_id.text().length);

                var prepay_id = response.xml.return_code.text();

                // console.log('解析后的prepay_id==',response.xml.return_code.text());

                //将预支付订单和其他信息一起签名后返回给前端

                let finalsign = wxpay.paysignjsapifinal(appid,mch_id,prepay_id,nonce_str,timestamp,mchkey);

                res.json({'appId':appid,'partnerId':mchid,'prepayId':prepay_id,'nonceStr':nonce_str,'timeStamp':timestamp,'package':'Sign=WXPay','sign':finalsign});

            });

        }

    });

})

app.listen(3000,()=>{

    console.log('服务器启动了....');

});