PHP结合Redis来限制用户或者IP某个时间段内访问的次数

$redis = new Redis();
$redis->connect('127.0.0.1', 6379);   

//获取客户端真实ip地址
function get_real_ip(){
    static $realip;
    if(isset($_SERVER)){
        if(isset($_SERVER['HTTP_X_FORWARDED_FOR'])){
            $realip=$_SERVER['HTTP_X_FORWARDED_FOR'];
        }else if(isset($_SERVER['HTTP_CLIENT_IP'])){
            $realip=$_SERVER['HTTP_CLIENT_IP'];
        }else{
            $realip=$_SERVER['REMOTE_ADDR'];
        }
    }else{
        if(getenv('HTTP_X_FORWARDED_FOR')){
            $realip=getenv('HTTP_X_FORWARDED_FOR');
        }else if(getenv('HTTP_CLIENT_IP')){
            $realip=getenv('HTTP_CLIENT_IP');
        }else{
            $realip=getenv('REMOTE_ADDR');
        }
    }
    return $realip;
}  

//这个key记录该ip的访问次数 也可改成用户id
$key = get_client_ip();  //该Key记录访问的次数，目前是以IP为例，也可以把用户id作为key，如userid_123456

//限制次数为3次。
$limit = 3;  

$check = $redis->exists($key);
if($check){
    $redis->incr($key);
    $count = $redis->get($key);
    if($count > 3){
        exit('已经超出了限制次数');
    }
}else{
    $redis->incr($key);
    //限制时间为60秒
    $redis->expire($key,60);
}  

$count = $redis->get($key);
echo '第 '.$count.' 次请求';