XAMPP | Mail2Disk script

<?php
/**
 * Mail2Disk XAMPP utility for native sendmail function
 *
 *  In php.ini set following:
 *  sendmail_path="C:\xampp\php\php.exe C:\xampp\mailtodisk\mailtodisk.php"
 *              (path to php executable) (path to this script)
 *
 */


// Absolute path to folder we would like to store our emails in
const MAIL_DIR = 'C:\\XAMPP\\mailtodisk\\';

// File extension of recieved email message
const MAIL_EXT = '.eml';

$input = file_get_contents('php://stdin');
$filename = MAIL_DIR . 'mail-' . gmdate('Ymd-Hi-s') . MAIL_EXT;
$retry = 0;

while(is_file($filename))
{
    $filename = MAIL_DIR . 'mail-' . gmdate('Ymd-Hi-s') . '-' . ++$retry . MAIL_EXT;
}

file_put_contents($filename, $input);
?>