public static function getRequestHeaderList() { if (!empty(self::$headers)) { return self::$headers; } if (function_exists('apache_request_headers')) { self::$headers = apache_request_headers(); } else { foreach ($_SERVER as $key => $value) { if (substr($key, 0, 5) == "HTTP_") { $name = self::extractHeader($key, "_", 5); self::$headers[$name] = $value; } } } return self::$headers; }