redis限制單ip、單用戶的訪問次數

有時候我們需要限制一個api或頁面訪問的頻率，例如單ip或單用戶一分鐘之內只能訪問多少次 
類似於這樣的需求很容易用Redis來實現

<?php
$redis = new Redis();
$redis->connect('127.0.0.1', 6379);
$redis->auth("php001");
//這個key記錄該ip的訪問次數 也可改成用戶id
//$key = 'userid_11100';
$key=get_real_ip();

//限制次數爲5
$limit = 5;

$check = $redis->exists($key);
if($check){
    $redis->incr($key);
    $count = $redis->get($key);
    if($count > 5){
        exit('請求太頻繁，請稍後再試！');
    }
}else{
    $redis->incr($key);
    //限制時間爲60秒
    $redis->expire($key,60);
}

$count = $redis->get($key);
echo '第 '.$count.' 次請求';

//獲取客戶端真實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;
}
?>