Working IPN Handler with Parallel Payments – PayPal Adaptive Payments

Hey everyone,

Just a dummy implementation of a Parallel Payment and an accompanying IPN Handler using the C#/.NET SDK. Feel free to use it however you like.

//Handles PayPal IPN
        public String IPN()
        {
            //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(Request.ContentLength);
            string strRequest = Encoding.ASCII.GetString(param);
            strRequest += "&cmd=_notify-validate";
            req.ContentLength = strRequest.Length;

            //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")
            {
                //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
            }
            else
            {
                //log response/ipn data for manual investigation
            }


            return "";
        }

        //Pay for an order
        public void Pay(int OrderId)
        {
            RequestEnvelope envelopeRequest = new RequestEnvelope();
            envelopeRequest.errorLanguage = "en_US";
            PaySample paySample = new PaySample();
           
            List listReceiver = new List();
            // Amount to be credited to the receiver's account
            Receiver receiverA = new Receiver(Convert.ToDecimal("4.00"));

            // A receiver's email address
            receiverA.email = "test_buyer1@learnerlessons.com.au";
            listReceiver.Add(receiverA);

            // Amount to be credited to the receiver's account
            Receiver receiverB = new Receiver(Convert.ToDecimal("2.00"));

            // A receiver's email address
            receiverB.email = "test_buyer2@learnerlessons.com.au";
            listReceiver.Add(receiverB);

            ReceiverList receiverList = new ReceiverList(listReceiver);

            PayRequest requestPay = new PayRequest(envelopeRequest, "PAY", "http://localhost:53034/orders/cancel", "AUD", receiverList, "http://localhost:53034/orders/return");
            requestPay.reverseAllParallelPaymentsOnError = true;
            requestPay.ipnNotificationUrl = "http://123.123.123.123/Orders/IPN";

            //Send request to paypal, retrieve payKey
            PayResponse payResponse = paySample.PayAPIOperations(requestPay);

            Response.Redirect("https://www.sandbox.paypal.com/cgi-bin/webscr?cmd=_ap-payment&paykey=" + payResponse.payKey);
        }