獲取訪問者的IP

    public function get_ip(){
        if (getenv("HTTP_CLIENT_IP") && strcasecmp(getenv("HTTP_CLIENT_IP"), "unknown"))
        $ip = getenv("HTTP_CLIENT_IP");
        else if (getenv("HTTP_X_FORWARDED_FOR") && strcasecmp(getenv("HTTP_X_FORWARDED_FOR"), "unknown"))
        $ip = getenv("HTTP_X_FORWARDED_FOR");
        else if (getenv("REMOTE_ADDR") && strcasecmp(getenv("REMOTE_ADDR"), "unknown"))
        $ip = getenv("REMOTE_ADDR");
        else if (isset($_SERVER['REMOTE_ADDR']) && $_SERVER['REMOTE_ADDR'] && strcasecmp($_SERVER['REMOTE_ADDR'], "unknown"))
        $ip = $_SERVER['REMOTE_ADDR'];
        else
        $ip = "unknown";
        return($ip);
    }