############################################################################################################################
##################  PayPal IPN verification - by Carol Braileanu of CyberTech SRL  -  cartman@b.astral.ro ##################
############################################################################################################################

// build the POST string adding the cmd=_notify-validate value

$req = "cmd=_notify_validate";

foreach($_POST as $key=>$value)
{
$value = urlencode(stripslashes($value));
$req .= "&" . $key . "=" . $value;
}

// construct the form to post
$header .= "POST /cgi-bin/webscr HTTP/1.0 \r\n";
$header .= "Content-Type: application/x-www-form-urlencoded \r\n";
$header .= "Content-Length: " . strlen($req) . "\r\n\r\n";

// open connection to server
$fp = fsockopen("www.paypal.com", 80);

$item_number = $_POST["item_number"];
$payment_status = $_POST["payment_status"];
$txn_id = $_POST["txn_id"];


if(!$fp)
{
	echo "cant contact IPN server";
}
else
{
	fputs($fp, $header . $req);
	while(!feof($fp))
	{
		$res = fgets($fp, 1024);
		if (strcmp($res, "VERIFIED")==0)
	{
		echo "successful";
	}
	else if (strcmp($res, "VERIFIED")==0)
	{
		echo "invalid";
	}
	}
fclose ($fp);
}