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<?php
declare(strict_types=1);
/**
* @copyright Copyright (c) 2017 Lukas Reschke <lukas@statuscode.ch>
*
* @author Christoph Wurst <christoph@winzerhof-wurst.at>
* @author Lukas Reschke <lukas@statuscode.ch>
* @author Morris Jobke <hey@morrisjobke.de>
* @author Roeland Jago Douma <roeland@famdouma.nl>
*
* @license GNU AGPL version 3 or any later version
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU Affero 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 Affero General Public License for more details.
*
* You should have received a copy of the GNU Affero General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*
*/
namespace OC\Security\RateLimiting\Backend;
use OCP\AppFramework\Utility\ITimeFactory;
use OCP\ICache;
use OCP\ICacheFactory;
/**
* Class MemoryCache uses the configured distributed memory cache for storing
* rate limiting data.
*
* @package OC\Security\RateLimiting\Backend
*/
class MemoryCache implements IBackend {
/** @var ICache */
private $cache;
/** @var ITimeFactory */
private $timeFactory;
/**
* @param ICacheFactory $cacheFactory
* @param ITimeFactory $timeFactory
*/
public function __construct(ICacheFactory $cacheFactory,
ITimeFactory $timeFactory) {
$this->cache = $cacheFactory->createDistributed(__CLASS__);
$this->timeFactory = $timeFactory;
}
/**
* @param string $methodIdentifier
* @param string $userIdentifier
* @return string
*/
private function hash(string $methodIdentifier,
string $userIdentifier): string {
return hash('sha512', $methodIdentifier . $userIdentifier);
}
/**
* @param string $identifier
* @return array
*/
private function getExistingAttempts(string $identifier): array {
$cachedAttempts = $this->cache->get($identifier);
if ($cachedAttempts === null) {
return [];
}
$cachedAttempts = json_decode($cachedAttempts, true);
if (\is_array($cachedAttempts)) {
return $cachedAttempts;
}
return [];
}
/**
* {@inheritDoc}
*/
public function getAttempts(string $methodIdentifier,
string $userIdentifier,
int $seconds): int {
$identifier = $this->hash($methodIdentifier, $userIdentifier);
$existingAttempts = $this->getExistingAttempts($identifier);
$count = 0;
$currentTime = $this->timeFactory->getTime();
/** @var array $existingAttempts */
foreach ($existingAttempts as $attempt) {
if (($attempt + $seconds) > $currentTime) {
$count++;
}
}
return $count;
}
/**
* {@inheritDoc}
*/
public function registerAttempt(string $methodIdentifier,
string $userIdentifier,
int $period) {
$identifier = $this->hash($methodIdentifier, $userIdentifier);
$existingAttempts = $this->getExistingAttempts($identifier);
$currentTime = $this->timeFactory->getTime();
// Unset all attempts older than $period
foreach ($existingAttempts as $key => $attempt) {
if (($attempt + $period) < $currentTime) {
unset($existingAttempts[$key]);
}
}
$existingAttempts = array_values($existingAttempts);
// Store the new attempt
$existingAttempts[] = (string)$currentTime;
$this->cache->set($identifier, json_encode($existingAttempts));
}
}
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