First, open wechat Pay

1.1 Associated merchant Number

Wechat public account platform, functions, wechat Payment, merchant account management, associated merchant number

1.2 Adding a Merchant Number

Cloud development platform Settings Other Settings wechat Payment configuration Add merchant number

1.3 Administrator Authorization

1.2 On that picture, click Authorize. The administrator’s wechat will pop up with a prompt and click “confirm authorization”.

Sub_mch_id does not match sub_appID.

Second, cloud function development

2.1 Creating a Cloud Function

2.2 Cloud function code

\pay\index.js

const cloud = require('wx-server-sdk')
cloud.init({
  env: cloud.DYNAMIC_CURRENT_ENV
})

exports.main = async (event, context) => {    
const res = await cloud.cloudPay.unifiedOrder({
    "body" : event.body,
    "outTradeNo" : event.outTradeNo,
    "spbillCreateIp" : "127.0.0.1"."subMchId" : "0000000000".// The key is the sub-merchant ID, but it is the normal merchant ID
    "totalFee" : parseInt(event.totalFee),   UnifiedOrder :fail WX API error: -202
    "envId": "ooo-xxxxxxxxxxxxxxxx".// Here is the id of the cloud environment to which the callback function belongs
    "functionName": "payCallBack".// This is the callback function name
    "nonceStr":event.nonceStr,            // There is no nonceStr and tradeType in the relevant cloud function code in the official documentation. When testing, nonceStr does not exist, the error will be reported
    "tradeType":"JSAPI"
  })
  return res
}
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2.3 Uploading and Deploying cloud Functions

Three, small program call

3.1 Unified Order

• The data obtained after the wechat order, it is best to save to the database, keep the bottom
• To adjust the wechat payment interface

// Call the cloud function, wechat unified order
  cloudPay(){
    var _this = this
    this.setData({
      body: "Bill Payment - XXXXX".outTradeNo: this.data.id+"-"+util.uuid(16),
      totalFee: this.data.totalCost*100 // Unit of payment: cent
    })
    app.showLoading(true)
    wx.cloud.callFunction({
      name: "pay".data: {
        body: _this.data.body,
        outTradeNo: _this.data.outTradeNo,
        totalFee: _this.data.totalFee,
        nonceStr:util.uuid(32)// Call your own uuid function
      },
      success(res) {
        // errCode: 0
        // errMsg: "cloudPay.unifiedOrder:ok"
        // returnCode: "FAIL"
        // returnMsg: "total_fee is empty. "
        console.log("Submission successful", res.result)
        if(res.result.returnCode! ="SUCCESS"){
          app.showToast(res.result.returnMsg)
          return
        }
        _this.unifiedOrder(res.result)
        // _this.requestPayment(res.result)
      },
      fail(res) {
        console.log("Submission failed", res)
      }
    })
  },
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3.2 Setting up the wechat payment interface

  // Official standard payment method, set up the payment interface
  requestPayment(payData) {
    var _this = this;
    const payment = payData.payment// The result of the previous function directly combines the parameters to be used in this functionwx.requestPayment({ ... payment,/ /... Is the syntax for expanding variables
      success(res) {
        console.log("Payment successful", res)
        _this.paySuccess()
      },
      fail(res) {
        console.log("Payment failure", res)
      }
    })
  },
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3.2 Payment callback successfully

• It is not recommended to go directly torequestPaymentthesuccessIn the callback function, perform the successful payment operation
• It is best to build another cloud functionpayCallBack
• The cloud functionpayCallBackCall the interface of our home-built server to execute the successful payment operation
• This is how to call the HTTP interface in the cloud function, but I’m not sure. Why not

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