WeChat mini program connects to WeChat payment
Nowadays, mini programs are becoming more and more popular, and the development of WeChat mini programs is also constantly improving. Now we will talk about how WeChat mini programs can access WeChat payment.
WeChat applet launches WeChat payment API interface
We can find the payment interface wx.requestPayment(Object object) of the WeChat applet in WeChat's official development documentation , where we can find the required parameters and formats. Example code:
wx.requestPayment({
timeStamp: '', // 时间戳，从 1970 年 1 月 1 日 00:00:00 至今的秒数，即当前的时间
nonceStr: '', // 随机字符串，长度为32个字符以下
package: '', // 统一下单接口返回的 prepay_id 参数值，提交格式如：prepay_id=***
signType: 'MD5',
paySign: '', // 签名，具体签名方案参见 小程序支付接口文档
success(res) {
}, // 接口调用成功的回调函数
fail(res) {
} // 接口调用失败的回调函数
})
Legal value of object.signType ----MD5 or HMAC-SHA256
Of course, these parameters need to be processed by your own backend (node) to obtain the parameters and return them to the WeChat applet.
WeChat payment interface document
Initiate WeChat payment. For more information, please view the WeChat payment interface documentation ;
The main interactions between the merchant system (node backend) and the WeChat payment system are :
- The login interface is called in the applet to obtain the user's openid. For API, please refer to the public API;
- The merchant server calls the payment to place an order uniformly. For API, please refer to the public API.
- The merchant server calls to sign again. For API, please refer to the public API.
- The merchant server receives payment notifications. For API, please refer to the public API.
- The merchant server queries the payment results. For API, please refer to the public API.
It is mainly a signature generation algorithm . The algorithm example is the function getSign(signParams) in the node code example below.
node backend sample code :
/*
* @Author: zhangyong
* @Date: 2018-04-17
* @Descrition : wechat 微信支付功能
*/
var queryString = require('querystring');
var crypto = require('crypto');
var request = require('request');
var uuid = require('uuid');
var sql = require('./assets/sql/sql')
var xml2jsparseString = require('xml2js').parseString;
// 引入项目的配置信息
const CONFIG = require('../config')
var config = CONFIG.app_info;
// wechat 支付类 (使用 es6 的语法)
class WechatAppletPay {
/**
* 构造函数
* @param params 传递进来的方法
*/
constructor( userInfo ){
this.userInfo = userInfo;
this.order_id = "";
}
/**
* 获取微信统一下单参数
*/
getUnifiedorderXmlParams(obj){
var body = '<xml> ' +
'<appid>'+config.wxappid+'</appid> ' +
'<body>'+obj.body+'</body> ' +
'<mch_id>'+config.mch_id+'</mch_id> ' +
'<nonce_str>'+obj.nonce_str+'</nonce_str> ' +
'<notify_url>'+obj.notify_url+'</notify_url>' +
'<openid>'+obj.openid+'</openid> ' +
'<out_trade_no>'+obj.out_trade_no+'</out_trade_no>'+
'<spbill_create_ip>'+obj.spbill_create_ip+'</spbill_create_ip> ' +
'<total_fee>'+obj.total_fee+'</total_fee> ' +
'<trade_type>'+obj.trade_type+'</trade_type> ' +
'<sign>'+obj.sign+'</sign> ' +
'</xml>';
return body;
}
/**
* 获取微信统一下单的接口数据
*/
getPrepayId(obj){
var that = this;
// 生成统一下单接口参数
var UnifiedorderParams = {
appid : config.wxappid,
body : obj.bookid,
mch_id : config.mch_id,
nonce_str: this.createNonceStr(),
notify_url : obj.notify_url,// 微信付款后的回调地址
openid : this.userInfo.openid,
out_trade_no : uuid.v4().replace(/-/g,''),//new Date().getTime(), //订单号
spbill_create_ip : obj.spbill_create_ip,
total_fee : obj.total_fee,
trade_type : 'JSAPI'
};
that.order_id = UnifiedorderParams.out_trade_no;
// 返回 promise 对象
return new Promise(function (resolve, reject) {
// 获取 sign 参数
UnifiedorderParams.sign = that.getSign(UnifiedorderParams);
var url = 'https://api.mch.weixin.qq.com/pay/unifiedorder';
request.post({
url : url, body:JSON.stringify(that.getUnifiedorderXmlParams(UnifiedorderParams))}, function (error, response, body) {
var prepay_id = '';
if (!error && response.statusCode == 200) {
// 微信返回的数据为 xml 格式， 需要装换为 json 数据， 便于使用
xml2jsparseString(body, {
async:true}, function (error, result) {
prepay_id = result.xml.prepay_id[0];
// 放回数组的第一个元素
resolve(prepay_id);
});
} else {
reject(body);
}
});
})
}
/**
* 获取微信支付的签名
* @param payParams
*/
getSign(signParams){
// 按参数名ASCII码从小到大排序
var keys = Object.keys(signParams);
keys = keys.sort();
var newArgs = {
};
keys.forEach(function (val, key) {
if (signParams[val]){
newArgs[val] = signParams[val];
}
})
// 拼接API密钥
var string = queryString.stringify(newArgs)+'&key='+config.wxpaykey;
// 生成签名
return crypto.createHash('md5').update(queryString.unescape(string), 'utf8').digest("hex").toUpperCase();
}
/**
* 微信支付的所有参数
* @param req 请求的资源, 获取必要的数据
*/
getBrandWCPayParams( obj, callback ){
var that = this;
var prepay_id_promise = that.getPrepayId(obj);
prepay_id_promise.then(function (prepay_id) {
var prepay_id = prepay_id;
var wcPayParams = {
"appId" : config.wxappid, // 微信小程序的APPID
"timeStamp" : parseInt(new Date().getTime() / 1000).toString(), //时间戳，自1970年以来的秒数
"nonceStr" : that.createNonceStr(), // 随机串
// 通过统一下单接口获取
"package" : "prepay_id="+prepay_id,
"signType" : "MD5", // 微信签名方式：
};
wcPayParams.paySign = that.getSign(wcPayParams); //微信支付签名
wcPayParams.order_id = that.order_id; //微信支订单号
callback(wcPayParams);
},function (error) {
callback(error);
});
}
/**
* 获取随机的NonceStr
*/
createNonceStr() {
return Math.random().toString(36).substr(2, 15);
};
}
module.exports = WechatAppletPay;
Call WechatAppletPay method
var WechatAppletPay= new WechatAppletPay(userInfo);
WechatAppletPay.getBrandWCPayParams(req.body, function (data) {
console.log(data);
})