php页面防止刷新代码

        //代理IP直接退出
        empty($_SERVER['HTTP_VIA']) or exit('Access Denied');
        //防止快速刷新
        session_start();
        $seconds = '3'; //时间段[秒]
        $refresh = '5'; //刷新次数
        //设置监控变量
        $cur_time = time();
        if(isset($_SESSION['last_time'])){
            $_SESSION['refresh_times'] += 1;
        }else{
            $_SESSION['refresh_times'] = 1;
            $_SESSION['last_time']     = $cur_time;
        }
        //处理监控结果
        if($cur_time - $_SESSION['last_time'] < $seconds){
            if($_SESSION['refresh_times'] >= $refresh){
                //跳转至攻击者服务器地址
                header(sprintf('Location:%s', 'http://127.0.0.1'));
                exit('Access Denied');
            }
        }else{
            $_SESSION['refresh_times'] = 0;
            $_SESSION['last_time'] = $cur_time;
        }