app/Services/RateLimitService.php
<?php
/**
* webtrees: online genealogy
* Copyright (C) 2023 webtrees development team
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <https://www.gnu.org/licenses/>.
*/
declare(strict_types=1);
namespace Fisharebest\Webtrees\Services;
use Fisharebest\Webtrees\Contracts\UserInterface;
use Fisharebest\Webtrees\Http\Exceptions\HttpTooManyRequestsException;
use Fisharebest\Webtrees\Site;
use LogicException;
use function array_filter;
use function count;
use function explode;
use function intdiv;
use function strlen;
use function time;
/**
* Throttle events to prevent abuse.
*/
class RateLimitService
{
private int $now;
/**
*
*/
public function __construct()
{
$this->now = time();
}
/**
* Rate limit for actions related to a user, such as password reset request.
* Allow $num requests every $seconds
*
* @param int $num allow this number of events
* @param int $seconds in a rolling window of this number of seconds
* @param string $limit name of limit to enforce
*
* @return void
*/
public function limitRateForSite(int $num, int $seconds, string $limit): void
{
$history = Site::getPreference($limit);
$history = $this->checkLimitReached($num, $seconds, $history);
Site::setPreference($limit, $history);
}
/**
* Rate limit for actions related to a user, such as password reset request.
* Allow $num requests every $seconds
*
* @param UserInterface $user limit events for this user
* @param int $num allow this number of events
* @param int $seconds in a rolling window of this number of seconds
* @param string $limit name of limit to enforce
*
* @return void
*/
public function limitRateForUser(UserInterface $user, int $num, int $seconds, string $limit): void
{
$history = $user->getPreference($limit);
$history = $this->checkLimitReached($num, $seconds, $history);
$user->setPreference($limit, $history);
}
/**
* Rate limit - allow $num requests every $seconds
*
* @param int $num allow this number of events
* @param int $seconds in a rolling window of this number of seconds
* @param string $history comma-separated list of previous timestamps
*
* @return string updated list of timestamps
* @throws HttpTooManyRequestsException
*/
private function checkLimitReached(int $num, int $seconds, string $history): string
{
// Make sure we can store enough previous timestamps in a database field.
$max = intdiv(256, strlen($this->now . ','));
if ($num > $max) {
throw new LogicException('Cannot store ' . $num . ' previous events in the database');
}
// Extract the timestamps.
$timestamps = array_filter(explode(',', $history));
// Filter events within our time window.
$filter = fn (string $x): bool => (int) $x >= $this->now - $seconds && (int) $x <= $this->now;
$in_window = array_filter($timestamps, $filter);
if (count($in_window) >= $num) {
throw new HttpTooManyRequestsException();
}
$timestamps[] = (string) $this->now;
while (count($timestamps) > $max) {
array_shift($timestamps);
}
return implode(',', $timestamps);
}
}