Process PayPal IPN with cURL

<?php
// Set the request paramaeter
$req = 'cmd=_notify-validate';

// Run through the posted array
foreach ($_POST as $key => $value)
{
	// If magic quotes is enabled strip slashes
	if (get_magic_quotes_gpc())
	{
		$_POST[$key] = stripslashes($value);
		$value = stripslashes($value);
	}
	$value = urlencode($value);
	// Add the value to the request parameter
	$req .= "&$key=$value";
}

$url = "http://www.paypal.com/cgi-bin/webscr";
$ch = curl_init();    // Starts the curl handler
curl_setopt($ch, CURLOPT_URL,$url); // Sets the paypal address for curl
curl_setopt($ch, CURLOPT_FAILONERROR, 1);
curl_setopt($ch, CURLOPT_RETURNTRANSFER,1); // Returns result to a variable instead of echoing
curl_setopt($ch, CURLOPT_TIMEOUT, 3); // Sets a time limit for curl in seconds (do not set too low)
curl_setopt($ch, CURLOPT_POST, 1); // Set curl to send data using post
curl_setopt($ch, CURLOPT_POSTFIELDS, $req); // Add the request parameters to the post
$result = curl_exec($ch); // run the curl process (and return the result to $result
curl_close($ch);

if (strcmp ($result, "VERIFIED") == 0) // It may seem strange but this function returns 0 if the result matches the string So you MUST check it is 0 and not just do strcmp ($result, "VERIFIED") (the if will fail as it will equate the result as false)
{
	// Do some checks to ensure that the payment has been sent to the correct person
	// Check and ensure currency and amount are correct
	// Check that the transaction has not been processed before
	// Ensure the payment is complete
}
else 
{
	// Log an invalid request to look into
}
?>