PayPal how to get post back params if response is FAIL - paypal

Question

Could I get post back params if in scenario to a buyer click 'cancel and return to xxx store'? below code is how I tried to have post back params echo out after buyer click cancel during the palpal webscr process:
$req = 'cmd=_notify-synch';
$pp_hostname = "www.sandbox.paypal.com";
$tx_token = $_GET['tx'];
$auth_token = "Ti-bfX-sv-zNDXZS";
$req .= "&tx=".$tx_token."&at=".$auth_token;
$ch = curl_init();
curl_setopt($ch, CURLOPT_URL, "https://".$pp_hostname."/cgi-bin/webscr");
curl_setopt($ch, CURLOPT_POST, 1);
curl_setopt($ch, CURLOPT_RETURNTRANSFER,1);
curl_setopt($ch, CURLOPT_POSTFIELDS, $req);
curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, 1);
//set cacert.pem verisign certificate path in curl using 'CURLOPT_CAINFO' field here,
//if your server does not bundled with default verisign certificates.
curl_setopt($ch, CURLOPT_SSL_VERIFYHOST, 2);
curl_setopt($ch, CURLOPT_HTTPHEADER, array("Host: ".$pp_hostname));
$res = curl_exec($ch);
curl_close($ch);
if(!$res){
//HTTP ERROR
}else{
// parse the data
$lines = explode("\n", $res);
$keyarray = array();
if(strcmp($lines[0], "SUCCESS") == 0){
for($i=1; $i<count($lines);$i++){
list($key,$val) = explode("=", $lines[$i]);
$keyarray[urldecode($key)] = urldecode($val);
}
//process payment
}else if(strcmp($lines[0], "FAIL") == 0){
$lines = explode("\n", $res);
$keyarray = array();
for($i=1; $i<count($lines);$i++){
list($key,$val) = explode("=", $lines[$i]);
$keyarray[urldecode($key)] = urldecode($val);
}
// echo post back params if FAIL
echo "<p><h3>Transaction ".$keyarray['payment_status']."!</h3></p>";
}
}
Is that possible to get post back params if response FAIL? I need some data to process in db if buyer cancel the transaction.
Thanks.

Answer 1

PayPal would not pass back any parameters to your cancel your, but you could pass back your own. You could dynamically populate the cancel URL that helps you to identify the user or order, and then read that on the cancel URL. For example, you could dynamically populate the cancel URL to something like https://www.mysite.com/cancel.php?orderid=483723 and then you would do your own look up in your system based on the order id, or what ever you pass over and back to your cancel URL.

Answer 2

paypal provide all things about transaction information for more information check below link info
reason_code
https://developer.paypal.com/webapps/developer/docs/classic/ipn/integration-guide/IPNandPDTVariables/