public static function static_constructor() { self::$allowed_request_headers = array('Host', 'Referer', 'Range', 'Cookie'); self::$custom_request_headers = array('User-Agent' => 'YouTube Cache', 'X-Cache-Admin' => $GLOBALS['admin_email']); self::$cached_headers = array('Content-Type', 'Content-Length', 'Last-Modified', 'Server'); }