IPN Listener

$value) {
if($get_magic_quotes_exists == true && get_magic_quotes_gpc() == 1) {
$value = urlencode(stripslashes($value));
} else {
$value = urlencode($value);
}
$req .= “&$key=$value”;
}
// Post IPN data back to PayPal to validate the IPN data is genuine
// Without this step anyone can fake IPN data
if(USE_SANDBOX == true) {
$paypal_url = “https://www.sandbox.paypal.com/cgi-bin/webscr”;
} else {
$paypal_url = “https://www.paypal.com/cgi-bin/webscr”;
}
$ch = curl_init($paypal_url);
if ($ch == FALSE) {
return FALSE;
}
curl_setopt($ch, CURLOPT_HTTP_VERSION, CURL_HTTP_VERSION_1_1);
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);
curl_setopt($ch, CURLOPT_SSL_VERIFYHOST, 2);
curl_setopt($ch, CURLOPT_FORBID_REUSE, 1);
if(DEBUG == true) {
curl_setopt($ch, CURLOPT_HEADER, 1);
curl_setopt($ch, CURLINFO_HEADER_OUT, 1);
}
// CONFIG: Optional proxy configuration
//curl_setopt($ch, CURLOPT_PROXY, $proxy);
//curl_setopt($ch, CURLOPT_HTTPPROXYTUNNEL, 1);
// Set TCP timeout to 30 seconds
curl_setopt($ch, CURLOPT_CONNECTTIMEOUT, 30);
curl_setopt($ch, CURLOPT_HTTPHEADER, array(‘Connection: Close’));
// CONFIG: Please download ‘cacert.pem’ from “http://curl.haxx.se/docs/caextract.html” and set the directory path
// of the certificate as shown below. Ensure the file is readable by the webserver.
// This is mandatory for some environments.
//$cert = __DIR__ . “./cacert.pem”;
//curl_setopt($ch, CURLOPT_CAINFO, $cert);
$res = curl_exec($ch);
if (curl_errno($ch) != 0) // cURL error
{
if(DEBUG == true) {
error_log(date(‘[Y-m-d H:i e] ‘). “Can’t connect to PayPal to validate IPN message: ” . curl_error($ch) . PHP_EOL, 3, LOG_FILE);
}
curl_close($ch);
exit;
} else {
// Log the entire HTTP response if debug is switched on.
if(DEBUG == true) {
error_log(date(‘[Y-m-d H:i e] ‘). “HTTP request of validation request:”. curl_getinfo($ch, CURLINFO_HEADER_OUT) .” for IPN payload: $req” . PHP_EOL, 3, LOG_FILE);
error_log(date(‘[Y-m-d H:i e] ‘). “HTTP response of validation request: $res” . PHP_EOL, 3, LOG_FILE);
}
curl_close($ch);
}
// Inspect IPN validation result and act accordingly
// Split response headers and payload, a better way for strcmp
$tokens = explode(“\r\n\r\n”, trim($res));
$res = trim(end($tokens));
if (strcmp ($res, “VERIFIED”) == 0) {
// check whether the payment_status is Completed
// check that txn_id has not been previously processed
// check that receiver_email is your PayPal email
// check that payment_amount/payment_currency are correct
// process payment and mark item as paid.
// assign posted variables to local variables
//$item_name = $_POST[‘item_name’];
//$item_number = $_POST[‘item_number’];
//$payment_status = $_POST[‘payment_status’];
//$payment_amount = $_POST[‘mc_gross’];
//$payment_currency = $_POST[‘mc_currency’];
//$txn_id = $_POST[‘txn_id’];
//$receiver_email = $_POST[‘receiver_email’];
//$payer_email = $_POST[‘payer_email’];

if(DEBUG == true) {
error_log(date(‘[Y-m-d H:i e] ‘). “Verified IPN: $req “. PHP_EOL, 3, LOG_FILE);
}
} else if (strcmp ($res, “INVALID”) == 0) {
// log for manual investigation
// Add business logic here which deals with invalid IPN messages
if(DEBUG == true) {
error_log(date(‘[Y-m-d H:i e] ‘). “Invalid IPN: $req” . PHP_EOL, 3, LOG_FILE);
}
}
?>

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