I am wondering how I should handle a situation where a customer was billed for digital goods, so then the IPN is called and I deliver the digital good. What happens if something goes wrong in the delivery process? How should this case be handled? Is there something I can do to cancel / refund in this case?
I'm basing my IPN code off of a sample I found
protected void Page_Load(object sender, EventArgs e){ //Post back to either sandbox or live string strSandbox = "https://www.sandbox.paypal.com/cgi-bin/webscr"; // string strLive = "https://www.paypal.com/cgi-bin/webscr"; 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); streamOut.Write(strRequest); streamOut.Close(); StreamReader streamIn = new StreamReader(req.GetResponse().GetResponseStream()); string strResponse = streamIn.ReadToEnd(); streamIn.Close(); if (strResponse == "VERIFIED") { //UPDATE YOUR DATABASE //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") { //UPDATE YOUR DATABASE } else { //UPDATE YOUR DATABASE }}What if my updating of the database fails?