利用Memcache來限制訪問次數過快

 <?php

$limit = 50;
$seconds = 60;
$block_for_seconds = 300;

$status = ‘OK’;

$memcache = new Memcache;
$memcache->connect(‘localhost’, 11211);

$ip = $_SERVER['REMOTE_ADDR'];

$r = $memcache->get($ip, array(‘c’, ‘t’));

$c = 1; // count
$init_time = time();
if($r) {
$s = $r[3]; // status
$c = $r[0]+1;
$init_time = $r[1];
if($s == ‘TOO_MANY_REQUESTS’) {
$d = time()-$r[1]; // time since block
if($block_for_seconds-$d > 0) { // still blocked
die(‘Flood detected!! You are going to wait ‘.($block_for_seconds-$d).’ and try again.’);
} else { // block is over
$status = ‘OK’;
$init_time = time();
$c = 0;
}
}

$new_time = time();
if($c > $limit) { // check if happened within a minute
$time_elapsed = $new_time – $init_time;
if($time_elapsed < $seconds) {
$status = ‘TOO_MANY_REQUESTS’;
}
print “time elapsed: $time_elapsed, count:$c”;
$c = 0;
$init_time = time();
}
}
print_r($r);
$memcache->set($ip, array($c, $init_time, $new_time, $status) );
?>