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<?php
/**
* SPDX-FileCopyrightText: 2016-2024 Nextcloud GmbH and Nextcloud contributors
* SPDX-FileCopyrightText: 2016 ownCloud, Inc.
* SPDX-License-Identifier: AGPL-3.0-only
*/
namespace OC\Memcache;
use OCP\IMemcacheTTL;
class Redis extends Cache implements IMemcacheTTL {
/** name => [script, sha1] */
public const LUA_SCRIPTS = [
'dec' => [
'if redis.call("exists", KEYS[1]) == 1 then return redis.call("decrby", KEYS[1], ARGV[1]) else return "NEX" end',
'720b40cb66cef1579f2ef16ec69b3da8c85510e9',
],
'cas' => [
'if redis.call("get", KEYS[1]) == ARGV[1] then redis.call("set", KEYS[1], ARGV[2]) return 1 else return 0 end',
'94eac401502554c02b811e3199baddde62d976d4',
],
'cad' => [
'if redis.call("get", KEYS[1]) == ARGV[1] then return redis.call("del", KEYS[1]) else return 0 end',
'cf0e94b2e9ffc7e04395cf88f7583fc309985910',
],
'ncad' => [
'if redis.call("get", KEYS[1]) ~= ARGV[1] then return redis.call("del", KEYS[1]) else return 0 end',
'75526f8048b13ce94a41b58eee59c664b4990ab2',
],
'caSetTtl' => [
'if redis.call("get", KEYS[1]) == ARGV[1] then redis.call("expire", KEYS[1], ARGV[2]) return 1 else return 0 end',
'fa4acbc946d23ef41d7d3910880b60e6e4972d72',
],
];
private const MAX_TTL = 30 * 24 * 60 * 60; // 1 month
/**
* @var \Redis|\RedisCluster $cache
*/
private static $cache = null;
public function __construct($prefix = '', string $logFile = '') {
parent::__construct($prefix);
}
/**
* @return \Redis|\RedisCluster|null
* @throws \Exception
*/
public function getCache() {
if (is_null(self::$cache)) {
self::$cache = \OC::$server->get('RedisFactory')->getInstance();
}
return self::$cache;
}
public function get($key) {
$result = $this->getCache()->get($this->getPrefix() . $key);
if ($result === false) {
return null;
}
return self::decodeValue($result);
}
public function set($key, $value, $ttl = 0) {
$value = self::encodeValue($value);
if ($ttl === 0) {
// having infinite TTL can lead to leaked keys as the prefix changes with version upgrades
$ttl = self::DEFAULT_TTL;
}
$ttl = min($ttl, self::MAX_TTL);
return $this->getCache()->setex($this->getPrefix() . $key, $ttl, $value);
}
public function hasKey($key) {
return (bool)$this->getCache()->exists($this->getPrefix() . $key);
}
public function remove($key) {
if ($this->getCache()->unlink($this->getPrefix() . $key)) {
return true;
} else {
return false;
}
}
public function clear($prefix = '') {
// TODO: this is slow and would fail with Redis cluster
$prefix = $this->getPrefix() . $prefix . '*';
$keys = $this->getCache()->keys($prefix);
$deleted = $this->getCache()->del($keys);
return (is_array($keys) && (count($keys) === $deleted));
}
/**
* Set a value in the cache if it's not already stored
*
* @param string $key
* @param mixed $value
* @param int $ttl Time To Live in seconds. Defaults to 60*60*24
* @return bool
*/
public function add($key, $value, $ttl = 0) {
$value = self::encodeValue($value);
if ($ttl === 0) {
// having infinite TTL can lead to leaked keys as the prefix changes with version upgrades
$ttl = self::DEFAULT_TTL;
}
$ttl = min($ttl, self::MAX_TTL);
$args = ['nx'];
$args['ex'] = $ttl;
return $this->getCache()->set($this->getPrefix() . $key, $value, $args);
}
/**
* Increase a stored number
*
* @param string $key
* @param int $step
* @return int | bool
*/
public function inc($key, $step = 1) {
return $this->getCache()->incrBy($this->getPrefix() . $key, $step);
}
/**
* Decrease a stored number
*
* @param string $key
* @param int $step
* @return int | bool
*/
public function dec($key, $step = 1) {
$res = $this->evalLua('dec', [$key], [$step]);
return ($res === 'NEX') ? false : $res;
}
/**
* Compare and set
*
* @param string $key
* @param mixed $old
* @param mixed $new
* @return bool
*/
public function cas($key, $old, $new) {
$old = self::encodeValue($old);
$new = self::encodeValue($new);
return $this->evalLua('cas', [$key], [$old, $new]) > 0;
}
/**
* Compare and delete
*
* @param string $key
* @param mixed $old
* @return bool
*/
public function cad($key, $old) {
$old = self::encodeValue($old);
return $this->evalLua('cad', [$key], [$old]) > 0;
}
public function ncad(string $key, mixed $old): bool {
$old = self::encodeValue($old);
return $this->evalLua('ncad', [$key], [$old]) > 0;
}
public function setTTL($key, $ttl) {
if ($ttl === 0) {
// having infinite TTL can lead to leaked keys as the prefix changes with version upgrades
$ttl = self::DEFAULT_TTL;
}
$ttl = min($ttl, self::MAX_TTL);
$this->getCache()->expire($this->getPrefix() . $key, $ttl);
}
public function getTTL(string $key): int|false {
$ttl = $this->getCache()->ttl($this->getPrefix() . $key);
return $ttl > 0 ? (int)$ttl : false;
}
public function compareSetTTL(string $key, mixed $value, int $ttl): bool {
$value = self::encodeValue($value);
return $this->evalLua('caSetTtl', [$key], [$value, $ttl]) > 0;
}
public static function isAvailable(): bool {
return \OC::$server->get('RedisFactory')->isAvailable();
}
protected function evalLua(string $scriptName, array $keys, array $args) {
$keys = array_map(fn ($key) => $this->getPrefix() . $key, $keys);
$args = array_merge($keys, $args);
$script = self::LUA_SCRIPTS[$scriptName];
$result = $this->getCache()->evalSha($script[1], $args, count($keys));
if ($result === false) {
$result = $this->getCache()->eval($script[0], $args, count($keys));
}
return $result;
}
protected static function encodeValue(mixed $value): string {
return is_int($value) ? (string)$value : json_encode($value);
}
protected static function decodeValue(string $value): mixed {
return is_numeric($value) ? (int)$value : json_decode($value, true);
}
}
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