C# ATOM Payment Gateway Implementation

1. Payment Request Page
   
   protected void Page_Load(object sender, EventArgs e)
   {
   try
   {           
       string ATOMPaymentIP = ATOMPaymentIP // PROVIDED BY ATOM //203.114.240.183--Stage
       string ATOMLogin = ATOMLogin // PROVIDED BY ATOM
       string ATOMPassword = ATOMPassword // PROVIDED BY ATOM
       string ATOMTransactionType = ATOMTransactionType // PROVIDED BY ATOM
       string ATOMProductId = ATOMProductId // PROVIDED BY ATOM
   
       HttpWebRequest request = (HttpWebRequest)WebRequest.Create("http://" + ATOMPaymentIP + "/paynetz/epi/fts");
   
       request.Method = "POST";
   
       request.ContentType = "application/x-www-form-urlencoded";
       request.UserAgent = "Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.2; SV1; CK={CVxk71YSfgiE6+6P6ftT7lWzblrdvMbRqavYf/6OcMIH8wfE6iK7TNkcwFAsxeChX7qRAlQhvPWso3KI6Jthvnvls9scl+OnAEhsgv+tuvs=}; .NET CLR 1.1.4322; .NET CLR 2.0.50727)";
       int pos = Request.Url.AbsoluteUri.LastIndexOf('/');
      
       // PAYMENT RESPONSE PAGE
       string strURL = Request.Url.AbsoluteUri.Substring(0, pos + 1) + "PaymentResponseATOM.aspx";
      
       string postData = "custacc=1234567890&login=" + ATOMLogin + "&pass=" + ATOMPassword + "&ttype=" + ATOMTransactionType + "&prodid=" + ATOMProductId + "&amt=" + PAYMENT AMOUNT + "&txncurr=INR&txnscamt=0&clientcode=" + CLIENT CODE(USER DEFINED) + "=&txnid=" + TRANSACTION ID + "&date=" + DateTime.Now.ToString("dd/mm/yyyy hh:mm:ss") + "&ru=" + strURL + "&udf1=" + FIRST NAME + "&udf2=" + EMAIL OF CUSTOMER + "&udf3=" + CUSTOMER MOBILE + "&udf4=" + CUSTOMER ADDRESS + "&udf5=" + EMI OPTION IF REQUIRED(BANK NAME) + "&udf6=" + EMI OPTION IF REQUIRED;
   
       byte[] byteArray = Encoding.UTF8.GetBytes(postData);
   
       request.ContentType = "application/x-www-form-urlencoded";
   
       request.ContentLength = byteArray.Length;
       request.AllowAutoRedirect = true;
   
       request.Proxy.Credentials = CredentialCache.DefaultCredentials;
   
       Stream dataStream = request.GetRequestStream();
   
       dataStream.Write(byteArray, 0, byteArray.Length);
   
       dataStream.Close();
   
       WebResponse response = request.GetResponse();
   
       XmlDocument objXML = new XmlDocument();
   
       dataStream = response.GetResponseStream();
   
       objXML.Load(dataStream);
   
       string TxnId = objXML.DocumentElement.ChildNodes[0].ChildNodes[0].ChildNodes[2].InnerText;
   
       string Token = objXML.DocumentElement.ChildNodes[0].ChildNodes[0].ChildNodes[3].InnerText;
       string txnData = "ttype=NBFundTransfer&txnStage=1&tempTxnId=" + TxnId + "&token=" + Token;
   
       dataStream.Close();
       response.Close();
       Response.Redirect("http://" + ATOMPaymentIP + "/paynetz/epi/fts?" + txnData);
   }
   catch (Exception ex)
   {
       HANDLE ERROR   
   }
   }
2. Payment Response Page
   
   protected void Page_Load(object sender, EventArgs e)
   {
   try
   {
       if (!IsPostBack)
       {
       NameValueCollection nvc = Request.Form;
       string mmp_Transaction = nvc["mmp_txn"].ToString();
       string PaymentStatus = nvc["f_code"].ToString();
       string MerchantTransactionId = Request.Form["mer_txn"];
   
       string Amount = Request.Form["amt"];
       string Product = Request.Form["prod"];
       string TransactionDate = Request.Form["date"];
       string BankTransactionId = Request.Form["bank_txn"];
       string ClientCode = Request.Form["clientcode"]; // Encrypted User Information
       string BankName = Request.Form["bank_name"];
   
       //User Details
       string Udf1 = Request.Form["udf1"]; //First Name
       string Udf2 = Request.Form["udf2"]; //Email
       string Udf3 = Request.Form["udf3"]; //Mobile
       string Udf4 = Request.Form["udf4"]; //Address
       string Udf5 = Request.Form["udf5"]; //Bank Name
       string Udf6 = Request.Form["udf6"]; //EMI Option
   
       string strResponceIP = HttpContext.Current.Request.UserHostAddress;
       string strRemarks = "txnId:" + MerchantTransactionId + ", txnStatus:" + PaymentStatus + ", amount:" + Amount + ", pgTxnId:" + mmp_Transaction + ", BankTransactionId:" + BankTransactionId + ", Udf1:" + Udf1 + ", Udf2:" + Udf2 + ", Udf3:" + Udf3 + ", Udf4:" + Udf4 + ", Udf5:" + Udf5 + ", Udf6:" + Udf6;
   
      
       string ATOMPaymentIP = ConfigurationManager.AppSettings["ATOMPaymentIP"].ToString();//203.114.240.183--Stage
       //Verify the Response Server
       if (Request.UrlReferrer.Host.Trim() != ATOMPaymentIP)
       {
           // REDIRECT TO ERROR PAGE IF RESPONSE IP IS NOT VERIFIED
       }
   
       // CHECK THE PAYMENT STATUS AND VALIDATE THE TRANSACTION ID
       if (PaymentStatus.ToUpper().Trim() == "OK" && transactionid.Trim()==MerchantTransactionId.Trim())
       {
           //"Transaction proceed successfully."
   
           // UPDATE THE TRANSACTION STATUS IN DB
           //
           // CODE FOR UPDATE STATUS
           //
           //
          
           // REDIRECT TO SUCCESS PAGE OR SHOW THE PAYMENT RESPONSE ON SAME PAGE   
   
       }
       else
       {
           // PAYMENT STATUS IS NOT SUCCESS OR TRANSACTION ID IS NOT VERIFIED
           // REDIRECT TO ERROR PAGE
       }
       }
   }
   catch (Exception ex)
   {
       // HANDLE ERROR
   }
   }