php 通过redis限制速度

limitRquestRate.php

<?php
$ip = $_SERVER['REMOTE_ADDR'];
$time = $_SERVER['REQUEST_TIME'];
$maxPerSecond = 10;
try {
  $redis = new Redis();
	$redis -> connect('127.0.0.1', 6379, 20);
	$redis -> lpush($ip, $time);
	if(
		($redis -> llen ($ip) >= $maxPerSecond) && ($redis -> lrange($ip, $maxPerSecond - 1, $maxPerSecond - 1))[0] + 1 >= $time
	) {
		//sleep(3);

		echo 'request too much';

	} else {
		echo 'normal';	
	}
	$redis -> ltrim($ip, 0, $maxPerSecond - 1);
} catch(Exception $e) {
	echo $e -> getMessage();
}