PHP HTTPS 변환 리다이렉트 하기

$prot = $_SERVER["HTTPS"];    //on   if($prot != "on"){  // HTTPS가 아니면 동작     $host = $_SERVER['HTTP_HOST'];             $request_uri = $_SERVER['REQUEST_URI'];             $m_url = "https://" . $host . $request_uri;             header( "HTTP/1.1 301 Moved Permanently" );             header( "Location: $m_url" );             exit; }