Simple LRU cache for TYPO3

ext_localconf.php

<?php
if (!defined('TYPO3_MODE')) {
    die('Access denied.');
}

/* *************************************************************
 *  Copyright notice
 *
 *  (c) 2018 Luis Antonio García Escobar <lgescobar@outlook.com>
 *
 *  All rights reserved
 *
 *  This script is part of the TYPO3 project. The TYPO3 project 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 2 of the License, or
 *  (at your option) any later version.
 *
 *  The GNU General Public License can be found at
 *  http://www.gnu.org/copyleft/gpl.html.
 *
 *  This script 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.
 *
 *  This copyright notice MUST APPEAR in all copies of the script!
 ***************************************************************/

// Register cache
if (!is_array($GLOBALS['TYPO3_CONF_VARS']['SYS']['caching']['cacheConfigurations']['extname'])) {
    $GLOBALS['TYPO3_CONF_VARS']['SYS']['caching']['cacheConfigurations']['extname'] = [];
}

if (!isset($GLOBALS['TYPO3_CONF_VARS']['SYS']['caching']['cacheConfigurations']['extname']['backend'])) {
    $GLOBALS['TYPO3_CONF_VARS']['SYS']['caching']['cacheConfigurations']['extname']['backend'] =
       \Vendor\Product\Cache\Backend\TransientMemoryLRUBackend::class;
}

// Define string frontend as default frontend because only the token (of type string) will be stored in cache.
if (!isset($GLOBALS['TYPO3_CONF_VARS']['SYS']['caching']['cacheConfigurations']['extname']['frontend'])) {
    $GLOBALS['TYPO3_CONF_VARS']['SYS']['caching']['cacheConfigurations']['extname']['frontend'] =
        \Vendor\Product\Cache\Frontend\RawFrontend::class;
}

if (!isset($GLOBALS['TYPO3_CONF_VARS']['SYS']['caching']['cacheConfigurations']['extname']['options'])) {
    $GLOBALS['TYPO3_CONF_VARS']['SYS']['caching']['cacheConfigurations']['extname']['options'] =
        ['maximumSize' => 10];
}

if (!isset($GLOBALS['TYPO3_CONF_VARS']['SYS']['caching']['cacheConfigurations']['extname']['groups'])) {
    $GLOBALS['TYPO3_CONF_VARS']['SYS']['caching']['cacheConfigurations']['extname']['groups'] = ['all'];
}

RawFrontend.php

<?php
namespace Vendor\Product\Cache\Frontend;

/* *************************************************************
 *  Copyright notice
 *
 *  (c) 2018 Luis Antonio García Escobar <lgescobar@outlook.com>
 *
 *  All rights reserved
 *
 *  This script is part of the TYPO3 project. The TYPO3 project 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 2 of the License, or
 *  (at your option) any later version.
 *
 *  The GNU General Public License can be found at
 *  http://www.gnu.org/copyleft/gpl.html.
 *
 *  This script 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.
 *
 *  This copyright notice MUST APPEAR in all copies of the script!
 ***************************************************************/

use TYPO3\CMS\Core\Cache\Frontend\StringFrontend;

/**
 * A cache frontend for the LRU cache.
 */
class RawFrontend extends StringFrontend
{
    /**
     * Saves the value of a PHP variable in the cache.
     *
     * @param string|int|float $entryIdentifier An identifier used for this cache entry
     * @param mixed $string The variable to cache
     * @param array $tags Tags to associate with this cache entry
     * @param int $lifetime Lifetime of this cache entry in seconds. If NULL is specified, the default lifetime is used. "0" means unlimited liftime.
     * @return void
     *
     * @throws \InvalidArgumentException If the identifier or tag is not valid
     * @throws \TYPO3\CMS\Core\Cache\Exception If no cache frontend has been set
     * @throws \TYPO3\CMS\Core\Cache\Exception\InvalidDataException It doesn't apply
     */
    public function set($entryIdentifier, $string, array $tags = [], $lifetime = null)
    {
        if (!$this->isValidEntryIdentifier($entryIdentifier)) {
            throw new \InvalidArgumentException('"' . $entryIdentifier . '" is not a valid cache entry identifier.', 1233057566);
        }

        foreach ($tags as $tag) {
            if (!$this->isValidTag($tag)) {
                throw new \InvalidArgumentException('"' . $tag . '" is not a valid tag for a cache entry.', 1233057512);
            }
        }

        $this->backend->set($entryIdentifier, $string, $tags, $lifetime);
    }

    /**
     * Checks the validity of an entry identifier. Returns TRUE if it's valid.
     *
     * @param string $identifier An identifier to be checked for validity
     * @return bool
     */
    public function isValidEntryIdentifier($identifier)
    {
        return is_string($identifier) || is_int($identifier) || is_float($identifier);
    }

    /**
     * Checks the validity of a tag. Returns TRUE if it's valid.
     *
     * @param string $tag An identifier to be checked for validity
     * @return bool
     */
    public function isValidTag($tag)
    {
        return is_string($tag);
    }
}

RelationUidTrait.php

<?php
namespace Vendor\Product\Domain\Model;

/* *************************************************************
 *  Copyright notice
 *
 *  (c) 2018 Luis Antonio García Escobar <lgescobar@outlook.com>
 *
 *  All rights reserved
 *
 *  This script is part of the TYPO3 project. The TYPO3 project 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 2 of the License, or
 *  (at your option) any later version.
 *
 *  The GNU General Public License can be found at
 *  http://www.gnu.org/copyleft/gpl.html.
 *
 *  This script 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.
 *
 *  This copyright notice MUST APPEAR in all copies of the script!
 ***************************************************************/

use TYPO3\CMS\Extbase\Persistence\Generic\LazyLoadingProxy;

trait RelationUidTrait
{
    /**
     * @param string $propertyName relation name (plural, lower camelCase)
     * @return int
     * @throws \ReflectionException
     */
    protected function getRelationUid($propertyName)
    {
        if ($this->$propertyName instanceof LazyLoadingProxy) {
            /** @var \ReflectionClass $reflectionClass */
            $reflectionClass = new \ReflectionClass(LazyLoadingProxy::class);
            $reflectionProperty = $reflectionClass->getProperty('fieldValue');
            $reflectionProperty->setAccessible(true);

            $uid = (int)$reflectionProperty->getValue($this->$propertyName);
        } elseif (is_numeric($this->$propertyName)) {
            $uid = $this->$propertyName;
        } elseif (is_null($this->$propertyName)) {
            $uid = 0;
        } else {
            $uid = $this->$propertyName->getUid();
        }

        return $uid;
    }
}

TransientMemoryLRUBackend.php

<?php
namespace Vendor\Product\Cache\Backend;

/* *************************************************************
 *  Copyright notice
 *
 *  (c) 2018 Luis Antonio García Escobar <lgescobar@outlook.com>
 *
 *  All rights reserved
 *
 *  This script is part of the TYPO3 project. The TYPO3 project 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 2 of the License, or
 *  (at your option) any later version.
 *
 *  The GNU General Public License can be found at
 *  http://www.gnu.org/copyleft/gpl.html.
 *
 *  This script 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.
 *
 *  This copyright notice MUST APPEAR in all copies of the script!
 ***************************************************************/

use TYPO3\CMS\Core\Cache\Backend\AbstractBackend;
use TYPO3\CMS\Core\Cache\Backend\TransientBackendInterface;

class TransientMemoryLRUBackend extends AbstractBackend implements TransientBackendInterface
{
    const FALLBACK_CACHE_SIZE = 25;

    /**
     * @var int
     */
    protected $maximumSize;

    /**
     * @var array
     */
    protected $entries = [];

    protected $accessCount = 0;

    protected $hitCount = 0;

    protected $missCount = 0;

    protected $setCount = 0;

    protected $evictionCount = 0;

    /**
     * @param int $maximumSize
     */
    public function setMaximumSize($maximumSize)
    {
        if (is_numeric($maximumSize)) {
            $maximumSize = (int)$maximumSize;
        }

        if (is_int($maximumSize) && $maximumSize > 0) {
            $this->maximumSize = $maximumSize;
        } else {
            $this->maximumSize = self::FALLBACK_CACHE_SIZE;
        }
    }

    function __destruct()
    {
        if (TYPO3_REQUESTTYPE & TYPO3_REQUESTTYPE_CLI) {
            echo json_encode([
                'accessCount' => $this->accessCount,
                'hitCount' => $this->hitCount,
                'missCount' => $this->missCount,
                'setCount' => $this->setCount,
                'evictionCount' => $this->evictionCount,
                'memoryPeakUsage' => memory_get_peak_usage() . ' B',
            ]);
        }
    }

    /**
     * Saves data in the cache.
     *
     * @param string $entryIdentifier An identifier for this specific cache entry
     * @param string $data The data to be stored
     * @param array $tags Tags to associate with this cache entry
     * @param int $lifetime Lifetime of this cache entry in seconds. If NULL is specified, the default lifetime is
     *     used. "0" means unlimited liftime.
     * @return void
     *
     * @throws \TYPO3\CMS\Core\Cache\Exception if no cache frontend has been set.
     */
    public function set($entryIdentifier, $data, array $tags = [], $lifetime = null)
    {
        if (!$this->cache instanceof \TYPO3\CMS\Core\Cache\Frontend\FrontendInterface) {
            throw new \TYPO3\CMS\Core\Cache\Exception('No cache frontend has been set yet via setCache().', 1238244992);
        }

        $this->setCount++;
        if (isset($this->entries[$entryIdentifier])) {
            $data = $this->entries[$entryIdentifier];
            unset($this->entries[$entryIdentifier]);
            $this->entries[$entryIdentifier] = $data;
        } else {
            if (count($this->entries) >= $this->maximumSize) {
                // remove least recently used element (front of array)
                $this->evictionCount++;
                reset($this->entries);
                unset($this->entries[key($this->entries)]);
            }

            $this->entries[$entryIdentifier] = $data;
        }
    }

    /**
     * Loads data from the cache.
     *
     * @param string $entryIdentifier An identifier which describes the cache entry to load
     * @return mixed The cache entry's content as a string or FALSE if the cache entry could not be loaded
     * @api
     */
    public function get($entryIdentifier)
    {
        $this->accessCount++;
        if (isset($this->entries[$entryIdentifier])) {
            $this->hitCount++;
            $data = $this->entries[$entryIdentifier];
            unset($this->entries[$entryIdentifier]);
            $this->entries[$entryIdentifier] = $data;
            return $data;
        } else {
            $this->missCount++;
            return false;
        }
    }

    /**
     * Checks if a cache entry with the specified identifier exists.
     *
     * @param string $entryIdentifier An identifier specifying the cache entry
     * @return bool TRUE if such an entry exists, FALSE if not
     * @api
     */
    public function has($entryIdentifier)
    {
        return isset($this->entries[$entryIdentifier]);
    }

    /**
     * Removes all cache entries matching the specified identifier.
     *
     * @param string $entryIdentifier Specifies the cache entry to remove
     * @return bool TRUE if the entry could be removed or FALSE if no entry was found
     * @api
     */
    public function remove($entryIdentifier)
    {
        if (isset($this->entries[$entryIdentifier])) {
            unset($this->entries[$entryIdentifier]);
            return true;
        } else {
            return false;
        }
    }

    /**
     * Removes all cache entries of this cache.
     *
     * @return void
     * @api
     */
    public function flush()
    {
        $this->entries = [];
    }

    /**
     * Does nothing
     *
     * @return void
     */
    public function collectGarbage()
    {
    }
}