Extend RealURL to store cHash when not already calculated

ext_localconf.php

<?php

$GLOBALS['TYPO3_CONF_VARS']['EXTCONF']['realurl']['storeInUrlCache']['realurl_cache_hash_generation'] = \Serfhos\RealurlCacheHashGeneration\Cache\StoreInUrlCacheHook::class . '->manipulateUrlCacheEntry';

StoreInUrlCacheHook.php

<?php

namespace Serfhos\RealurlCacheHashGeneration\Cache;

use DmitryDulepov\Realurl\Cache\UrlCacheEntry;
use TYPO3\CMS\Core\Utility\GeneralUtility;
use TYPO3\CMS\Frontend\Page\CacheHashCalculator;

/**
 * RealURL Hook: StoreInUrlCache
 * @package Serfhos\Realurl\CacheHashGeneration\Cache
 */
class StoreInUrlCacheHook
{
    /**
     * Store cHash when url not already generated based on incoming input..
     *
     * @param array $parameter
     */
    public function manipulateUrlCacheEntry($parameter)
    {
        $cacheEntry = $parameter['cacheEntry'];
        if ($cacheEntry instanceof UrlCacheEntry && !array_key_exists('cHash', $cacheEntry->getRequestVariables())) {
            $cacheHashParameters = $this->getCacheHashCalculator()->getRelevantParameters($cacheEntry->getOriginalUrl());
            if (!empty($cacheHashParameters)) {
                $calculatedCacheHash = $this->getCacheHashCalculator()->calculateCacheHash($cacheHashParameters);
                // Append cHash to current UrlCacheEntry
                $cacheEntry->setRequestVariables($cacheEntry->getRequestVariables() + ['cHash' => $calculatedCacheHash]);
            }
        }
    }

    /**
     * @return CacheHashCalculator
     */
    protected function getCacheHashCalculator()
    {
        return GeneralUtility::makeInstance(CacheHashCalculator::class);
    }
}