Friday, February 3, 2012

Paypal IPN in c#

// ASP .NET C#

using System;
using System.IO;
using System.Text;
using System.Net;
using System.Web;

public partial class csIPNexample : System.Web.UI.Page
protected void Page_Load(object sender, EventArgs e)
//Post back to either sandbox or live
string strSandbox = "";
string strLive = "";
HttpWebRequest req = (HttpWebRequest)WebRequest.Create(strSandbox);

//Set values for the request back
req.Method = "POST";
req.ContentType = "application/x-www-form-urlencoded";
byte[] param = Request.BinaryRead(HttpContext.Current.Request.ContentLength);
string strRequest = Encoding.ASCII.GetString(param);
strRequest += "&cmd=_notify-validate";
req.ContentLength = strRequest.Length;

//for proxy
//WebProxy proxy = new WebProxy(new Uri("http://url:port#"));
//req.Proxy = proxy;

//Send the request to PayPal and get the response
StreamWriter streamOut = new StreamWriter(req.GetRequestStream(), System.Text.Encoding.ASCII);
StreamReader streamIn = new StreamReader(req.GetResponse().GetResponseStream());
string strResponse = streamIn.ReadToEnd();

if (strResponse == "VERIFIED")
//check the payment_status is Completed
//check that txn_id has not been previously processed
//check that receiver_email is your Primary PayPal email
//check that payment_amount/payment_currency are correct
//process payment
else if (strResponse == "INVALID")
//log for manual investigation
//log response/ipn data for manual investigation