PHP防止快速刷新代码

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;
}