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WeChat Mini Program Payment Simple Examples and Precautions

高洛峰
高洛峰Original
2017-01-10 09:59:122430browse

WeChat Mini Program Payment

The payment of WeChat Mini Program is similar to the payment of WeChat official account. In comparison, it is simpler than the payment of official account. We only need to call WeChat’s unified ordering interface to obtain After prepay_id, we can call WeChat payment.

Today we will encapsulate the payment interface of general node! ! !

First we need to know some information to call the unified ordering interface

var bookingNo = 'davdian' + this.createNonceStr() + this.createTimeStamp()
  var deferred = Q.defer() 
  var appid = config.appId 
  var nonce_str = this.createNonceStr() 
  var timeStamp = this.createTimeStamp() 
  var url = "https://api.mch.weixin.qq.com/pay/unifiedorder"
  var formData = "<xml>"
  formData += "<appid>" + appid + "</appid>" //appid 
  formData += "<attach>" + attach + "</attach>" //附加数据 
  formData += "<body>" + body + "</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 += "<openid>" + openid + "</openid>"
  formData += "<out_trade_no>" + bookingNo + "</out_trade_no>"
  formData += "<spbill_create_ip>61.50.221.43</spbill_create_ip>"
  formData += "<total_fee>" + total_fee + "</total_fee>"
  formData += "<trade_type>JSAPI</trade_type>"
  formData += "<sign>" + this.paysignjsapi(appid, attach, body, mch_id, nonce_str, notify_url, openid, bookingNo, &#39;61.50.221.43&#39;, total_fee, &#39;JSAPI&#39;) + "</sign>"
  formData += "</xml>"
  var self = this
  request({ 
   url: url, 
   method: &#39;POST&#39;, 
   body: formData 
  }, function(err, response, body) { 
   if (!err && response.statusCode == 200) { 
    var prepay_id = self.getXMLNodeValue(&#39;prepay_id&#39;, body.toString("utf-8")) 
    var tmp = prepay_id.split(&#39;[&#39;) 
    var tmp1 = tmp[2].split(&#39;]&#39;) 
    //签名 
    var _paySignjs = self.paysignjs(appid, nonce_str, &#39;prepay_id=&#39; + tmp1[0], &#39;MD5&#39;, timeStamp) 
    var args = { 
     appId: appid, 
     timeStamp: timeStamp, 
     nonceStr: nonce_str, 
     signType: "MD5", 
     package: tmp1[0], 
     paySign: _paySignjs 
    }
    deferred.resolve(args) 
   } else { 
    console.log(body) 
   } 
  }) 
  return deferred.promise

This is the code of a unified ordering interface. We need appid applet public account id, mch_id merchant account id, openid small The only specification of the program is the password for key payment. The remaining parameters are the order information and price. I require entering the q module to use promise. This varies from person to person and can be set according to your own needs. We need to request the https://api.mch.weixin.qq.com/pay/unifiedorder interface

Note: The formdata we pass here is an xml instead of json

Then we need to sign Method, here we need to encapsulate two methods, one is the signature method that will be used to call the unified ordering interface, the other is used to call the mini program payment

unified ordering interface sign: 

var ret = { 
   appid: appid, 
   attach: attach, 
   body: body, 
   mch_id: mch_id, 
   nonce_str: nonce_str, 
   notify_url: notify_url, 
   openid: openid, 
   out_trade_no: out_trade_no, 
   spbill_create_ip: spbill_create_ip, 
   total_fee: total_fee, 
   trade_type: trade_type 
  } 
  var string = this.raw(ret) 
  string = string + &#39;&key=&#39; + key 
  var crypto = require(&#39;crypto&#39;) 
  var sign = crypto.createHash(&#39;md5&#39;).update(string, &#39;utf8&#39;).digest(&#39;hex&#39;) 
  return sign.toUpperCase()

Payment sign: 

var ret = {
    appId: appid,
    nonceStr: nonceStr,
    package: package,
    signType: signType,
    timeStamp: timeStamp
  }
  var string = this.raw(ret)
  string = string + &#39;&key=&#39; + key
  var sign = crypto.createHash(&#39;md5&#39;).update(string, &#39;utf8&#39;).digest(&#39;hex&#39;)
  return sign.toUpperCase()

Note that when encrypting, we get a string instead of a json, so we need to convert json into string, the code is as follows: 

var keys = Object.keys(args)
  keys = keys.sort()
  var newArgs = {}
  keys.forEach(function(key) {
    newArgs[key] = args[key]
  })
  var string = &#39;&#39;
  for (var k in newArgs) {
    string += &#39;&&#39; + k + &#39;=&#39; + newArgs[k]
  }
  string = string.substr(1)
  return string

The unified order interface returns xml with prepay_id, so we need a method to parse it. The code is as follows: 

var tmp = xml.split("<" + node_name + ">")
  var _tmp = tmp[1].split("</" + node_name + ">")
  return _tmp[0]

Finally we only need to connect these Together, you can obtain all the parameters required for WeChat payment. The code is as follows: 

//微信小程序支付封装,暂支持md5加密，不支持sha1
/**
***create order by jianchep 2016/11/22  
 **/
var config = require('../config/weapp.js')
var Q = require("q")
var request = require("request")
var crypto = require('crypto')
var ejs = require('ejs')
var fs = require('fs')
var key = config.key
module.exports = {
 // 获取prepay_id
 getXMLNodeValue: function(node_name, xml) {
  var tmp = xml.split("<" + node_name + ">")
  var _tmp = tmp[1].split("</" + node_name + ">")
  return _tmp[0]
 },
 // object-->string
 raw: function(args) {
  var keys = Object.keys(args)
  keys = keys.sort()
  var newArgs = {}
  keys.forEach(function(key) {
    newArgs[key] = args[key]
  })
  var string = &#39;&#39;
  for (var k in newArgs) {
    string += &#39;&&#39; + k + &#39;=&#39; + newArgs[k]
  }
  string = string.substr(1)
  return string
 },
  // 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) + ''
 },
 // 支付md5加密获取sign
 paysignjs: function(appid, nonceStr, package, signType, timeStamp) {
  var ret = {
    appId: appid,
    nonceStr: nonceStr,
    package: package,
    signType: signType,
    timeStamp: timeStamp
  }
  var string = this.raw(ret)
  string = string + &#39;&key=&#39; + key
  var sign = crypto.createHash(&#39;md5&#39;).update(string, &#39;utf8&#39;).digest(&#39;hex&#39;)
  return sign.toUpperCase()
 },
 // 统一下单接口加密获取sign
 paysignjsapi: function(appid, attach, body, mch_id, nonce_str, notify_url, openid, out_trade_no, spbill_create_ip, total_fee, trade_type) {
  var ret = {
   appid: appid,
   attach: attach,
   body: body,
   mch_id: mch_id,
   nonce_str: nonce_str,
   notify_url: notify_url,
   openid: openid,
   out_trade_no: out_trade_no,
   spbill_create_ip: spbill_create_ip,
   total_fee: total_fee,
   trade_type: trade_type
  }
  var string = this.raw(ret)
  string = string + '&key=' + key
  var crypto = require('crypto')
  var sign = crypto.createHash('md5').update(string, 'utf8').digest('hex')
  return sign.toUpperCase()
 },
 // 下单接口
 order: function(attach, body, mch_id, openid, total_fee, notify_url) {
  var bookingNo = 'davdian' + this.createNonceStr() + this.createTimeStamp()
  var deferred = Q.defer()
  var appid = config.appId
  var nonce_str = this.createNonceStr()
  var timeStamp = this.createTimeStamp()
  var url = "https://api.mch.weixin.qq.com/pay/unifiedorder"
  var formData = ""
  formData += "" + appid + "" //appid
  formData += "" + attach + "" //附加数据
  formData += "" + body + ""
  formData += "" + mch_id + "" //商户号
  formData += "" + nonce_str + "" //随机字符串，不长于32位。
  formData += "" + notify_url + ""
  formData += "" + openid + ""
  formData += "" + bookingNo + ""
  formData += "61.50.221.43"
  formData += "" + total_fee + ""
  formData += "JSAPI"
  formData += "" + this.paysignjsapi(appid, attach, body, mch_id, nonce_str, notify_url, openid, bookingNo, '61.50.221.43', total_fee, 'JSAPI') + ""
  formData += ""
  var self = this
  request({
   url: url,
   method: 'POST',
   body: formData
  }, function(err, response, body) {
   if (!err && response.statusCode == 200) {
    var prepay_id = self.getXMLNodeValue('prepay_id', body.toString("utf-8"))
    var tmp = prepay_id.split('[')
    var tmp1 = tmp[2].split(']')
    //签名
    var _paySignjs = self.paysignjs(appid, nonce_str, 'prepay_id=' + tmp1[0], 'MD5', timeStamp)
    var args = {
     appId: appid,
     timeStamp: timeStamp,
     nonceStr: nonce_str,
     signType: "MD5",
     package: tmp1[0],
     paySign: _paySignjs
    }
    deferred.resolve(args)
   } else {
    console.log(body)
   }
  })
  return deferred.promise
 }
}

After that, we encapsulate the order interface: 

unifiedorder: function (req, res) {
  var body = "测试支付"
  var openid = "openid"
  var total_fee = 1
  var notify_url = "http://localhost/notify"
  var mch_id = config.shopId
  var attach = "测试"
  wxpay.order(attach, body, mch_id, openid, total_fee, notify_url)
   .then(function(data){
    console.log(&#39;data--->&#39;, data, 123123)
    res.json(data)
   })
 },

Then we only need to call this interface in the mini program, and we will get all the payment information, and then make WeChat payment.

Here are some of the pitfalls of small program payment:

1. The unified ordering interface is xml (this is not just for small programs, but also for official accounts), and the return value is also in xml format and needs to be obtained by yourself. prepay_id,

2. The signature algorithm must bring the key, and finally it must be converted to a larger number

3. The sign algorithm of WeChat payment must also bring the appid (this is unscientific, a deep pit)

4. The signature algorithm must not use json to splice key

Thanks for reading, I hope it can help everyone, thank you for your support of this site!

For more WeChat applet payment simple examples and precautions related articles, please pay attention to the PHP Chinese website!

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