Forum Moderators: buckworks
// ***************** IPN LISTENER *********************
// PHP 4.1
// read the post from PayPal system and add 'cmd'
$req = 'cmd=_notify-validate';
foreach ($_POST as $key => $value) {
$value = urlencode(stripslashes($value));
$req .= "&$key=$value";
}
// post back to PayPal system to validate
$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";
// In a live application send it back to www.paypal.com
// but during development you will want to use the paypal sandbox
// So comment out one of the following lines
// $fp = fsockopen ('www.sandbox.paypal.com', 80, $errno, $errstr, 30);
$fp = fsockopen ('www.paypal.com', 80, $errno, $errstr, 30);
// or use port 443 for an SSL connection
//$fp = fsockopen ('ssl://www.paypal.com', 443, $errno, $errstr, 30);
if (!$fp) {
// HTTP ERROR
} else {
fputs ($fp, $header . $req);
while (!feof($fp)) {
$res = fgets ($fp, 1024);
if (strcmp ($res, "VERIFIED") == 0) {
// CODE TO UPDATE THE DATABASE TO SAY THAT
// IT HAS RETURNED VERIFIED
} else if (strcmp ($res, "INVALID") == 0) {
// CODE TO UPDATE THE DATABASE TO SAY THAT
// IT HAS RETURNED INVALID
} else {
// CODE TO UPDATE THE DATABASE TO SAY THAT
// IT HAS RETURNED NEITHER
}
}
fclose ($fp);
}
// ***************** END IPN LISTENER *********************
REASONS FOR INVALID
- Make sure you are posting back ALL variables/values.
For PayPal to return VERIFIED, your IPN script needs to post back ALL the variables that were posted to it in the first place. In other words, if your script only needs to manipulate 1 or 2 variables, it is not enough to post back to PayPal only the variables/values your script is concerned with. Your script should post back EVERYTHING that was initially posted to it from PayPal. This is the only way PayPal will return VERIFIED
- Make sure you are not posting back to the wrong URL.
If you are testing in the Sandbox, you need to ensure your script posts back to www.sandbox.paypal.com. If you are on the live site, the script should post back to www.paypal.com. You will receive INVALID if you are testing in the Sandbox and your script posts back to the live site (or vice versa)
- Encoding
PayPal's IPN server expects that your script will POST back all variables that were posted to it and more importantly, that they are encoded the same way as they were sent to your script. If your script inadvertently changed the encoding of a character or interprets an encoded character as another character and POSTs back, you will likely see INVALID. This can happen sporadically and tends to occur, for example, when a payment is received and the buyer may have an accented character in their name or the order is for some item with a non-standard character in the item name. These instances are tricky to troubleshoot but it is listed here as it can cause INVALID when you would expect VERIFIED. Look for this issue when you are seeing that certain IPNs are INVALID and all the rest are VERIFIED.
foreach ($_POST as $key => $value) {
$value = urlencode(stripslashes($value));
$req .= "&$key=$value";
}
$req .= '&'.http_build_query($_POST);
$fp = fsockopen ('ssl://www.sandbox.paypal.com', 443, $errno, $errstr, 30);
