easyappointments/application/helpers/rate_limit_helper.php

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<?php defined('BASEPATH') or exit('No direct script access allowed');
/* ----------------------------------------------------------------------------
* Easy!Appointments - Open Source Web Scheduler
*
* @package EasyAppointments
* @author A.Tselegidis <alextselegidis@gmail.com>
* @copyright Copyright (c) 2013 - 2020, Alex Tselegidis
* @license http://opensource.org/licenses/GPL-3.0 - GPLv3
* @link http://easyappointments.org
* @since v1.1.0
* ---------------------------------------------------------------------------- */
if ( ! function_exists('rate_limit'))
{
/**
* Rate-limit the application requests.
*
* Example:
*
* rate_limit($CI->input->ip_address(), 100, 300);
*
* @link https://github.com/alexandrugaidei-atomate/ratelimit-codeigniter-filebased
*
* @param string $ip Client IP address.
* @param int $max_requests Number of allowed requests, defaults to 100.
* @param int $duration In seconds, defaults to 5 minutes.
*/
function rate_limit($ip, $max_requests = 100, $duration = 300)
{
$CI =& get_instance();
$rate_limiting = $CI->config->item('rate_limiting');
if ( ! $rate_limiting)
{
return;
}
$CI->load->driver('cache', ['adapter' => 'file']);
$cache_key = str_replace(':', '', 'rate_limit_key_' . $ip);
$cache_remain_time_key = str_replace(':', '', 'rate_limit_tmp_' . $ip);
$current_time = date('Y-m-d H:i:s');
if ($CI->cache->get($cache_key) === FALSE) // First request
{
$current_time_plus = date('Y-m-d H:i:s', strtotime('+' . $duration . ' seconds'));
$CI->cache->save($cache_key, 1, $duration);
$CI->cache->save($cache_remain_time_key, $current_time_plus, $duration * 2);
}
else // Consequent request
{
$requests = $CI->cache->get($cache_key);
$time_lost = $CI->cache->get($cache_remain_time_key);
if ($current_time > $time_lost)
{
$current_time_plus = date('Y-m-d H:i:s', strtotime('+' . $duration . ' seconds'));
$CI->cache->save($cache_key, 1, $duration);
$CI->cache->save($cache_remain_time_key, $current_time_plus, $duration * 2);
}
else
{
$CI->cache->save($cache_key, $requests + 1, $duration);
}
$requests = $CI->cache->get($cache_key);
if ($requests > $max_requests)
{
header('HTTP/1.0 429 Too Many Requests');
exit;
}
}
}
}