贝宝PDT总是对我的HTTP发布请求C＃MVC返回Fail

Question

I am facing very weird kind of problem that after successful payment transaction, I am not able to get TransactionId appended with returningUrl. Since Paypal auto redirects me to my ReturnUrl which I have mentioned in PDT settings page, and Paypal appends the trasactionId to this returningUrl named tx and using that trasactionId I make a Post request to this Url

https://www.sandbox.paypal.com/cgi-bin/webscr

But here is the problem that I am not able to get that transactionId? what could be the problem kindly any body help me in this issue. This is my code that I am using to make an HTTP post request.

string authTokenTest = "sMfRi9rJN3AjqsejnMxFfkeIwhwrCmVZz3nplUy9V6a9Yq0_2YdugSvZYNa";

            //used this but could not retrieved "tx" 
            //string txToken = Request.QueryString.Get("tx"); 
            //Then used this but no use
            var queryValues = HttpUtility.ParseQueryString(Request.Url.Query);
            var txToken = queryValues["tx"];

            string query = string.Format("cmd=_notify-synch&tx={0}&at={1}", txToken, authTokenTest);

            //// Create the request back


            string strSandbox = "https://www.sandbox.paypal.com/cgi-bin/webscr";
            string url = strSandbox;

            /// to use HTTP 1.1 and TLS 1.2
            ServicePointManager.Expect100Continue = true;
            ServicePointManager.SecurityProtocol = (SecurityProtocolType)3072;
            ServicePointManager.DefaultConnectionLimit = 9999;

            HttpWebRequest req = (HttpWebRequest)WebRequest.Create(url);

            // Set values for the request back
            req.Method = "POST";
            req.ContentType = "application/x-www-form-urlencoded";
            req.ContentLength = query.Length;

            // Write the request back IPN strings
            StreamWriter stOut = new StreamWriter(req.GetRequestStream(), System.Text.Encoding.ASCII);
            stOut.Write(query);
            stOut.Close();

            // Do the request to PayPal and get the response

            HttpWebResponse payResp = (HttpWebResponse)req.GetResponse();
            StreamReader sr = new StreamReader(payResp.GetResponseStream());
            string strResponse = sr.ReadToEnd();
            sr.Close();

If I make a direct request to this URL via browser and append a TransactionId and IdentityToken then I get the success response, but in this way I am not getting any way the transactionId and my Response is always Fail. Kindly help my in this problem. What could be the issue in my code or any other problem to resolve this issue. Thanks for your time.

Answer 1

I use MVC and so use model binding to get the tx value from the query string. But I don't think that's your problem.

The Return URL has to be set, as you said you did. Also PDT has to be turned on in the same place the URL is specified. Also, unfortunately, customers will not be returned automatically to your site if they use a credit card instead of a PayPal account.

I'm implementing IPN though because credit card customers may not return to the site.