notify.php

<?php
require_once "ShoppingCart.php";


$shoppingCart = new ShoppingCart();


$raw_post_data = file_get_contents('php://input');
$raw_post_array = explode('&', $raw_post_data);
$myPost = array();
foreach ($raw_post_array as $keyval) {
	$keyval = explode ('=', $keyval);
	if (count($keyval) == 2)
		$myPost[$keyval[0]] = urldecode($keyval[1]);
}

// read the post from PayPal system and add 'cmd'
$req = 'cmd=_notify-validate';
if(function_exists('get_magic_quotes_gpc')) {
	$get_magic_quotes_exists = true;
}


foreach ($myPost as $key => $value) {
	if($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

$ch = curl_init("https://www.sandbox.paypal.com/cgi-bin/webscr");
if ($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);
curl_setopt($ch, CURLOPT_HEADER, 1);
curl_setopt($ch, CURLINFO_HEADER_OUT, 1);

// Set TCP timeout to 30 seconds
curl_setopt($ch, CURLOPT_CONNECTTIMEOUT, 30);
curl_setopt($ch, CURLOPT_HTTPHEADER, array('Connection: Close'));

$res = curl_exec($ch);


if (curl_errno($ch) != 0) // cURL error
	{
	error_log(date('[Y-m-d H:i e] '). "Can't connect to PayPal to validate IPN message: " . curl_error($ch) . PHP_EOL, 3, 'app.log');
	curl_close($ch);
	exit;
} else {
		// Log the entire HTTP response if debug is switched on.
		error_log(date('[Y-m-d H:i e] '). "HTTP request of validation request:". curl_getinfo($ch, CURLINFO_HEADER_OUT) ." for IPN payload: $req" . PHP_EOL, 3, 'app.log');
		error_log(date('[Y-m-d H:i e] '). "HTTP response of validation request: $res" . PHP_EOL, 3, 'app.log');
		curl_close($ch);
}
// Inspect IPN validation result and act accordingly
// Split response headers and payload, a better way for strcmp
$payment_response = $res;

$tokens = explode("\r\n\r\n", trim($res));
$res = trim(end($tokens));
if (strcmp ($res, "VERIFIED") == 0) {
	// 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'];
	
	// check whether the payment_status is Completed
	$isPaymentCompleted = false;
	if($payment_status == "Completed") {
		$isPaymentCompleted = true;
	}
	$payment_id = $shoppingCart->insertPayment($item_number, $payment_status, $payment_response);
	
	// process payment and mark item as paid.
	$shoppingCart->paymentStatusChange ( $item_number,"PAID" );
	error_log(date('[Y-m-d H:i e] '). "Verified IPN: $req ". PHP_EOL, 3, 'app.log');
	
} else if (strcmp ($res, "INVALID") == 0) {
	// log for manual investigation
	// Add business logic here which deals with invalid IPN messages
	error_log(date('[Y-m-d H:i e] '). "Invalid IPN: $req" . PHP_EOL, 3, 'app.log');
}
?>