Question

I am trying IPN callback, using servlet. The code I am using is provided by paypal for verifying the ipn data. But every time i getting a INVALID response.

Here is the code:

Enumeration en = req.getParameterNames();
String str = "cmd=_notify-validate";

    while (en.hasMoreElements()) {        
        String paramName = (String) en.nextElement();
        String paramValue = req.getParameter(paramName);

//str = str + "&" + paramName + "=" + URLEncoder.encode(paramValue,"UTF-8"); // for UTF-8 i set the encode format in my account as UTF-8
//str = str + "&" + paramName + "=" + URLEncoder.encode(paramValue,"ISO-8859-1");// for ISO-8859-1 i set the encode format in my account as ISO-8859-1
str = str + "&" + paramName + "=" + URLEncoder.encode(paramValue); //default as provided by paypal

    }
    URL u = new URL("http://www.sandbox.paypal.com/cgi-bin/webscr");
    URLConnection uc = u.openConnection();
    uc.setDoOutput(true);
    uc.setRequestProperty("Content-Type", "application/x-www-form-urlencoded");
    PrintWriter pw = new PrintWriter(uc.getOutputStream());
    pw.println(str);
    pw.close();

    BufferedReader in = new BufferedReader(new InputStreamReader(uc.getInputStream()));
    String res = in.readLine();
    in.close();

    if (res.equals("VERIFIED") || !res.equals("VERIFIED")) {
        //Update database...
    } else if (res.equals("INVALID")) {      
       //INVALID   
    }

I have checked all three possibilities provided by paypal in case paypal return INVALID as follow:

1) Missing Parameters – As I am send all the parameters no issue of missing parameters

2) Invalid URL. – I am using sandbox so URL is : http://www.sandbox.paypal.com/cgi-bin/webscr

3) Character encoding. – Tried with character encoding same as paypal account setting parameter encoding.

the request I am sending back to paypal using following parameters:

cmd=_notify-validate&last_name=User&test_ipn=1&address_name=Test+User&txn_type=web_accept&receiver_email=sellr1_1252495907_biz%40gmail.com&residence_country=US&address_city=San+Jose&payment_gross=&payment_date=01%3A55%3A04+Sep+26%2C+2009+PDT&address_zip=95131&payment_status=Completed&address_street=1+Main+St&first_name=Test&payer_email=buyer1_1252495751_per%40gmail.com&protection_eligibility=Eligible&payer_id=BXBKS22JQCUWL&verify_sign=AOMkeg7ofCL7FJfioyWA19uCxD4XAgZirsjiGh8cUy1fd2YAqBwOkkst&payment_type=instant&business=sellr1_1252495907_biz%40gmail.com&address_country_code=US&mc_fee=0.64&address_status=confirmed&transaction_subject=True+Up&quantity=1&notify_version=2.8&mc_currency=EUR&custom=&address_state=CA&payment_fee=&handling_amount=0.00&payer_status=verified&shipping=0.00&item_name=True+Up&tax=0.00&username=hannonj&charset=windows-1252&item_number=567&mc_gross=10.00&txn_id=7F456350BS7942738&receiver_id=MASSU6BSR9SC2&address_country=United+States

Please , can any one direct me to proper direction? I am not getting what is wrong the code or the URL or anything else. I tried all the possibilities. Please help me.

Answer 1

Thank you guys for your reply.
ohhh I solved it at last.

Actually in notify URL I also added a username parameter. Paypal want the parameter values for IPN same as it return to the servlet.(You can get it as req.getParameterNames()). As I have username parameter extra, which is not known to paypal. Paypal was returning INVALID.