CacheHashCalculator.php

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<?php
 
/*
 * This file is part of the TYPO3 CMS project.
 *
 * It is free software; you can redistribute it and/or modify it under
 * the terms of the GNU General Public License, either version 2
 * of the License, or any later version.
 *
 * For the full copyright and license information, please read the
 * LICENSE.txt file that was distributed with this source code.
 *
 * The TYPO3 project - inspiring people to share!
 */
 
namespace ‪TYPO3\CMS\Frontend\Page;
 
use ‪TYPO3\CMS\Core\SingletonInterface;
use ‪TYPO3\CMS\Core\Utility\GeneralUtility;
 
class ‪CacheHashCalculator implements ‪SingletonInterface
{
    protected ‪$configuration;
 
    public function ‪__construct(‪CacheHashConfiguration ‪$configuration = null)
    {
        $this->configuration = ‪$configuration ?? GeneralUtility::makeInstance(CacheHashConfiguration::class);
    }
 
    public function ‪calculateCacheHash(array $params)
    {
        return !empty($params) ? md5(serialize($params)) : '';
    }
 
    public function ‪generateForParameters($queryString)
    {
        $cacheHashParams = $this->‪getRelevantParameters($queryString);
        return $this->‪calculateCacheHash($cacheHashParams);
    }
 
    public function ‪doParametersRequireCacheHash($queryString)
    {
        if (!$this->configuration->hasData(‪CacheHashConfiguration::ASPECT_REQUIRED_CACHE_HASH_PRESENCE_PARAMETERS)) {
            return false;
        }
        $parameterNames = array_keys($this->‪splitQueryStringToArray($queryString));
        foreach ($parameterNames as $parameterName) {
            $hasRequiredParameter = $this->configuration->applies(
                ‪CacheHashConfiguration::ASPECT_REQUIRED_CACHE_HASH_PRESENCE_PARAMETERS,
                $parameterName
            );
            if ($hasRequiredParameter) {
                return  true;
            }
        }
        return false;
    }
 
    public function ‪getRelevantParameters($queryString)
    {
        $parameters = $this->‪splitQueryStringToArray($queryString);
        $relevantParameters = [];
        foreach ($parameters as $parameterName => $parameterValue) {
            if ($this->‪isAdminPanelParameter($parameterName) || $this->‪isExcludedParameter($parameterName) || $this->‪isCoreParameter($parameterName)) {
                continue;
            }
            if ($this->‪hasCachedParametersWhiteList() && !$this->‪isInCachedParametersWhiteList($parameterName)) {
                continue;
            }
            if (($parameterValue === null || $parameterValue === '') && $this->‪isAllowedWithEmptyValue($parameterName)) {
                continue;
            }
            $relevantParameters[$parameterName] = $parameterValue;
        }
        if (!empty($relevantParameters)) {
            if (empty($parameters['id'])) {
                throw new \RuntimeException('ID parameter needs to be passed for the cHash calculation!', 1467983513);
            }
            $relevantParameters['id'] = $parameters['id'];
            // Finish and sort parameters array by keys:
            $relevantParameters['encryptionKey'] = ‪$GLOBALS['TYPO3_CONF_VARS']['SYS']['encryptionKey'];
            ksort($relevantParameters);
        }
        return $relevantParameters;
    }
 
    protected function ‪splitQueryStringToArray($queryString)
    {
        $parameters = array_filter(explode('&', ltrim($queryString, '?')));
        $parameterArray = [];
        foreach ($parameters as $parameter) {
            // should not remove empty values with trimExplode, otherwise cases like &=value, value is used as parameterName.
            $parts = ‪GeneralUtility::trimExplode('=', $parameter, false);
            $parameterName = $parts[0];
            $parameterValue = $parts[1] ?? '';
            if (trim($parameterName) === '') {
                // This parameter cannot appear in $_GET in PHP even if its value is not empty, so it should be ignored!
                continue;
            }
            $parameterArray[rawurldecode($parameterName)] = rawurldecode($parameterValue);
        }
        return $parameterArray;
    }
 
    protected function ‪isAdminPanelParameter($key)
    {
        return $key === 'ADMCMD_simUser' || $key === 'ADMCMD_simTime' || $key === 'ADMCMD_prev';
    }
 
    protected function ‪isCoreParameter($key)
    {
        return $key === 'id' || $key === 'type' || $key === 'no_cache' || $key === 'cHash' || $key === 'MP';
    }
 
    protected function ‪isExcludedParameter($key)
    {
        return $this->configuration->applies(
            ‪CacheHashConfiguration::ASPECT_EXCLUDED_PARAMETERS,
            $key
        );
    }
 
    protected function ‪isInCachedParametersWhiteList($key)
    {
        return $this->configuration->applies(
            ‪CacheHashConfiguration::ASPECT_CACHED_PARAMETERS_WHITELIST,
            $key
        );
    }
 
    protected function ‪hasCachedParametersWhiteList()
    {
        return $this->configuration->hasData(
            ‪CacheHashConfiguration::ASPECT_CACHED_PARAMETERS_WHITELIST
        );
    }
 
    protected function ‪isAllowedWithEmptyValue($key)
    {
        return $this->configuration->shallExcludeAllEmptyParameters()
            || $this->configuration->applies(
                ‪CacheHashConfiguration::ASPECT_EXCLUDED_PARAMETERS_IF_EMPTY,
                $key
            );
    }
 
    public function ‪setConfiguration(array ‪$configuration)
    {
        $newConfiguration = GeneralUtility::makeInstance(
            CacheHashConfiguration::class,
            ‪$configuration ?? ‪$GLOBALS['TYPO3_CONF_VARS']['FE']['cacheHash'] ?? []
        );
        $this->configuration = $this->configuration->with($newConfiguration);
    }
}