nodejs+koa2微信app支付，小程序支付

企业付款到零钱文档；https://pay.weixin.qq.com/wiki/doc/api/tools/mch_pay.php?chapter=14_2

1，搞微信支付，先看流程图

https://pay.weixin.qq.com/wiki/doc/api/app/app.php?chapter=8_3，先看流程图，看懂，再看微信支付api

2.调用统一下单接口

const router = new Router()
const uuid = require('uuid')

router.post('wxpay', async (ctx, next) => {
//1.根据orderCode查询订单状态和付款金额，此处省略

const order = { //参数一定要按照acil码(也就是a,b,c,d)顺序来写，或者你需要按照acil码自己排序，否则会在支付时报签名错误
appid: '在微信中的应用appid,也在商户平台中',
body: '迪士尼',
mch_id: '微信平台中的商户编号',
nonce_str: (uuid.v4()).replace(/-/g, ''),
notify_url: '要回调的ulr,一定要是外网可访问的',
out_trade_no: orderInfo[0].orderCode,
spbill_create_ip: ctx.request.ip.replace(/::ffff:/g, ''),
total_fee: 1, //先1分钱
trade_type: 'APP' 
}
const objStr = objTostring(order)
const preSign = objStr + 'key=微信商户平台的key'
order.sign = endeurl.md5(preSign).toUpperCase()
const xml = objToXml(order)

//调用统一下单接口

const data = await request.postAsync({
url: 'https://api.mch.weixin.qq.com/pay/unifiedorder',
body: xml
})
const result = await parseStringAsync(data.body)

if (result.xml.result_code[0] == 'FAIL') {
throw {
message: 'orderStatus wrong'
}
}
//字符串必需按照顺序来
const paysign2 = {
appid: result.xml.appid[0],
noncestr: result.xml.nonce_str[0],
package: 'Sign=WXPay',
partnerid: result.xml.mch_id[0],
prepayid: result.xml.prepay_id[0],
timestamp: parseInt(Date.now() / 1000).toString() //注意：时间必需为秒
}
const payPrestr = objTostring(paysign2) + 'key=微信商户平台的key' //不知道的话，可以问老板
paysign2.sign = endeurl.md5(payPrestr).toUpperCase()

//二次签名，返回给app即可，由app端进行微信支付吊起
ctx.body = {
paysign2
}
})

3.工具类

const xml2js = require('xml2js')
const Parser = new xml2js.Parser()
exports.parseStringAsync = xml => {
return new Promise((resolve, reject) => {
Parser.parseString(xml, (err, result) => {
if (err) {
reject(err)
} else {
resolve(result)
}
})
})
}
exports.objTostring = obj => {
var preSign = '';
for (let key in obj) {
preSign += `${key}=${obj[key]}&`
}
return preSign
}

exports.objToXml = obj => {
let xml = '<xml>'
for (let key in obj) {
xml += `<${key}>${obj[key]}</${key}>`
}
xml += '</xml>'
return xml
}

3.微信回调你在第二步是的notify_url值

router.post('wxNotify', async (ctx, next) => {

//获取微信返回的参数值，查询订单状态

const data = ctx.params
var payQuery = {
appid: data.xml.appid[0],
mch_id: data.xml.mch_id[0],
nonce_str: data.xml.nonce_str[0],
out_trade_no: data.xml.out_trade_no[0],
transaction_id: data.xml.transaction_id[0]
}
let payQueryString = objTostring(payQuery) + 'key=微信商户平台的key'
payQuery.sign = endeurl.md5(payQueryString).toUpperCase()
//查询订单是否支付成功
const data1 = await request.postAsync({
url: 'https://api.mch.weixin.qq.com/pay/orderquery',
body: services.pay.objToXml(payQuery)
})

const result = await parseStringAsync(data1.body)

 if (result.xml.return_code[0] && result.xml.return_code[0] == 'SUCCESS' && result.xml.trade_state[0] == 'SUCCESS' ) {

//告诉微信，你收到支付结果通知了

const resXml = "<xml>" + "<return_code><![CDATA[SUCCESS]]></return_code>" +

"<return_msg><![CDATA[OK]]></return_msg>" + "</xml> "
ctx.body = {
resXml
}

//从result中比较价格和你订单中的金额是否一致，，进行后台业务处理，此处省略

})

总结： 

1.参数一定要按照acil码(也就是a,b,c,d)顺序来写，或者你需要按照acil码自己排序（Object.keys(json)），否则会在支付时报签名错误

2.时间戳单位为秒，北京时间，别玩坏了，国外时间不能在国内不能玩

3.如果在支付时，报签名错误，先检查参数是否排序／参数值正确，如果还不行，请重置商户平台的key,再者不行，给微信支付技术支持发邮件，人家会在2小时内回复的

4.node微信app支付，就是以上代码两部分，剩下的就是app的事了

 

二、补充微信小程序支付统一下单，回调和app支付一致，不再重复

router.post('xcxPay', async (ctx, next) => {
//1.根据orderCode查询订单状态和付款金额
const userId = ctx.user.userid
const orderInfo = await model.order.find({
'orderStatus.status': {
$in: [1, 9]
}
}, {
_id: 0,
orderCode: 1,
transCode: 1,
orderProducts: 1,
siteId: 1,
virtualProducts: 1,
CNYCharge: 1
})
if (!orderInfo || orderInfo.length < 1) {
throw {
status: 20001,
message: 'paying orderInfo not exists',
router: ctx._url
}
log(222, '订单状态错误', orderInfo)
return
}
const userOpenId = await model.user.findOne({
_id: userId
}, {
_id: 0,
openIds: 1
})
if (!userOpenId || (userOpenId && !userOpenId.openIds && !userOpenId.openIds.wcx)) {
throw {
status: 20001,
message: 'wcx openid is not find !',
router: ctx._url
}
return
}
let amount = orderInfo[0].CNYCharge

//字符串必需按照顺序来，比app支付参数稍有不同
const order = {
appid: '小程序appid',
body: '糖葫芦',
mch_id: '商户号',
nonce_str: (uuid.v4()).replace(/-/g, ''),
notify_url: `${config.apiUrl}/notify_url`,
openid: userOpenId && userOpenId.openIds && userOpenId.openIds.wcx || '', //小程序支付必须
out_trade_no: orderInfo[0].orderCode,
spbill_create_ip: ctx.request.ip.replace(/::ffff:/g, ''),
total_fee: Number(amount) * 100,
trade_type: 'JSAPI' //小程序支付必须
}
const objStr = services.pay.objTostring(order)
const preSign = objStr + 'key=商户平台key'
order.sign = endeurl.md5(preSign).toUpperCase()
const xml = services.pay.objToXml(order)
const data = await request.postAsync({
url: 'https://api.mch.weixin.qq.com/pay/unifiedorder',
body: xml
})
const result = await services.pay.parseStringAsync(data.body)
if (result.xml.result_code[0] == 'FAIL') {
throw {
message: 'orderStatus wrong'
}
}

const paysign2 = {
appId: result.xml.appid[0],
nonceStr: result.xml.nonce_str[0],
package: `prepay_id=${result.xml.prepay_id[0]}`,
signType: 'MD5',
timeStamp: parseInt(Date.now() / 1000).toString()
}
const payPrestr = services.pay.objTostring(paysign2) + 'key=商户平台key,同app支付'
paysign2.paySign = md5(payPrestr).toUpperCase()
ctx.body = {
paysign2
}
})