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Wechat Miniprogram

Payment Flow

  1. Merchant retrieve OpenID using “wx.login’s code” and “code2session api”
  2. Merchant make API call to 2C2P to get the wx.requestPayment (prepay_id)
  3. Merchant Invoke wx.requestPayment in MiniProgram
  4. WeChat shall prompt customer to confirm payment
  5. Wechat shall display payment result to customer
  6. WeChat shall notify a notification from 2C2P regarding payment result
  7. 2C2P shall notify payment result to Merchant

 

Getting OpenID

  1. Merchant shall invoke “wx.login” in miniprogram to get “code”
    Document: https://developers.weixin.qq.com/miniprogram/dev/api/open-api/login/wx.login.html
  2. Merchant shall submit “code” to merchant’s backend to retrieve openID
    Document: https://developers.weixin.qq.com/miniprogram/dev/api-backend/open-api/login/auth.code2Session.html

 

Integration Guide

  1. Make SecurePay Payment
    1.1) Information to make Wechat MiniProgram
  • paymentChannel is WCMINI
  • miniProgramData show following. Required appID & openID
<miniProgramData>
    <wechat>
      <appID>{appid}</appID>
      <openID>{openid}</openID>
    </wechat>
</miniProgramData>
  1. You will receive the response back from 2C2P with response code “32”
  2. You will read the “miniProgramData/wechat” xml tag to receive the wx.requestPayment payload

📘

Refer Wechat Request Payment Parameter

<miniProgramData>
    <wechat>
      {"timeStamp":"","package":"","nonceStr":"","signType":"","paySign":""}
    </wechat>
</miniProgramData>

 
Sample code show following

🚧

Environment

Please refer Demo & Live Endpoint.

📘

Secure Pay API

Refer Payload Refer Payload Parameter Specification & API Parameter Specification

#region ALL Fields

string cardholderEmail = "", payCategoryID = "", userDefined1 = "", userDefined2 = "", userDefined3 = "", userDefined4 = "", userDefined5 = "", storeCard = "",
    ippTransaction = "", installmentPeriod = "", interestType = "", recurring = "", invoicePrefix = "", recurringAmount = "", allowAccumulate = "", maxAccumulateAmt = "",
    recurringInterval = "", recurringCount = "", chargeNextDate = "", promotion = "", request3DS = "", statementDescriptor = "", agentCode = "", channelCode = "", paymentExpiry = "", mobileNo = "", tokenizeWithoutAuthorization = "",
    paymentChannel = "", storeCardUniqueID = "", panBank = "", userId = "", storeId = "", storeName = "", storeTerminalId = "", wxAppId = "", wxOpenId = "";

#endregion

// RETRIEVE merchantId, merchantSecretKey from your database
//Merchant Account Information
string merchantID = "JT01"; //Get MerchantID from 2c2p PGW Dashboard
string secretKey = "7jYcp4FxFdf0"; //Get SecretKey from 2c2p PGW Dashboard

//Product Information
string uniqueTransactionCode = "Invoice" + DateTime.Now.ToString ("yyMMddHHmmss");
string desc = "item 1";
string amt = "000000000001"; //12 digit format
string currencyCode = "702"; //Ref: http://en.wikipedia.org/wiki/ISO_4217

//Customer Information
string cardholderName = "John Doe";
string country = "SG";

//Payment Channel
paymentChannel = "WCMINI"; // Wechat App 

string miniprogramData = "";
wxAppId = "wx0ecdd8f41c8ac9ab"; // app id
wxOpenId = paymentData.openId; // openid
miniprogramData = "<wechat>" +
  "<appID>" + wxAppId + "</appID>" +
  "<openID>" + wxOpenId + "</openID>" +
  "</wechat>";

//Request Information
string timeStamp = DateTime.Now.ToString ("ddMMyyHHmmss");
string apiVersion = "9.9";

//Construct payment request message
string payloadXml = "<PaymentRequest>" +
    "<timeStamp>" + timeStamp + "</timeStamp>" +
    "<merchantID>" + merchantID + "</merchantID>" +
    "<uniqueTransactionCode>" + uniqueTransactionCode + "</uniqueTransactionCode>" +
    "<desc>" + HttpUtility.HtmlEncode (desc) + "</desc>" +
    "<amt>" + amt + "</amt>" +
    "<currencyCode>" + currencyCode + "</currencyCode>" +
    "<panCountry>" + country + "</panCountry>" +
    "<cardholderName>" + cardholderName + "</cardholderName>" +
    "<paymentChannel>" + paymentChannel + "</paymentChannel>" +
    "<miniProgramData>" +
    miniprogramData +
    "</miniProgramData>" +
    "</PaymentRequest>";

string payload = Utility.Base64Encode (payloadXml); //Convert payload to base64  
string hash = Utility.GetHMAC2 (payload, secretKey); //Calculate Hash Value

string xml = "<PaymentRequest>" +
    "<version>" + apiVersion + "</version>" + //request version number (9.9)
    "<payload>" + payload + "</payload>" + //request payload
    "<signature>" + hash + "</signature>" + //signature
    "</PaymentRequest>";

string data = Utility.Base64Encode (xml); //Convert payload to base64          
data = "paymentRequest=" + HttpUtility.UrlEncode (data); //urlEncode data

string url = "https://demo2.2c2p.com/2C2PFrontEnd/SecurePayment/Payment.aspx";

var paymentResponse = Utility.PostRequest (url, data, Utility.PostContentType.FORM);
if (paymentResponse.Result) {
    if (!string.IsNullOrEmpty (paymentResponse.ResultOutput)) {
        string clearResult = Utility.Base64Decode (paymentResponse.ResultOutput);
        XmlDocument xDoc = new XmlDocument ();
        xDoc.LoadXml (clearResult);
        string respPayload = (xDoc.SelectNodes ("//payload").Count > 0 ? xDoc.SelectSingleNode ("//payload").InnerText : "");
        string respSign = (xDoc.SelectNodes ("//signature").Count > 0 ? xDoc.SelectSingleNode ("//signature").InnerText : "");

        string respHash = Utility.GetHMAC2 (respPayload, secretKey); //Calculate Hash Value

        respPayload = Utility.Base64Decode (respPayload);
        if (respHash.Equals (respSign, StringComparison.OrdinalIgnoreCase)) {
            XmlDocument xDocResponse = new XmlDocument ();
            xDocResponse.LoadXml (respPayload);
            string respCode = (xDocResponse.SelectNodes ("//respCode").Count > 0 ? xDocResponse.SelectSingleNode ("//respCode").InnerText : "");
            if (respCode == "32") {
               string wechatData = (xDocResponse.SelectNodes ("//miniProgramData//wechat").Count > 0 ? xDocResponse.SelectSingleNode ("//miniProgramData//wechat").InnerText : "");
               return Json (wechatData); 
            } else {
                return BadRequest ("Failed to get requestPayment");
            }

        } else {
            return BadRequest ();
        }
    } else {
        return BadRequest ("Empty response");
    }
} else {
    return BadRequest (paymentResponse.ErrorDetails);
}

Updated almost 3 years ago