Qfyilyi

I am trying to get a cache working in my plugin.
In ext_localconf.php

if (!is_array($GLOBALS['TYPO3_CONF_VARS']['SYS']['caching']['cacheConfigurations']['myextension'])) {

$GLOBALS['TYPO3_CONF_VARS']['SYS']['caching']['cacheConfigurations']['myextension'] = ;}



if (!isset($GLOBALS['TYPO3_CONF_VARS']['SYS']['caching']['cacheConfigurations']['myextension']['frontend'])) {

$GLOBALS['TYPO3_CONF_VARS']['SYS']['caching']['cacheConfigurations']['myextension']['frontend'] = 'TYPO3\CMS\Core\Cache\Frontend\StringFrontend';}



if (!isset($GLOBALS['TYPO3_CONF_VARS']['SYS']['caching']['cacheConfigurations']['myextension']['options'])) {

$GLOBALS['TYPO3_CONF_VARS']['SYS']['caching']['cacheConfigurations']['myextension']['options'] = ['defaultLifetime' => 0];}



if (!isset($GLOBALS['TYPO3_CONF_VARS']['SYS']['caching']['cacheConfigurations']['myextension']['groups'])) {

$GLOBALS['TYPO3_CONF_VARS']['SYS']['caching']['cacheConfigurations']['myextension']['groups'] = ['pages'];}

In my controller action :

$cacheIdentifier = 'topic' . $topic->getUid();

$cache = GeneralUtility::makeInstance(CacheManager::class)->getCache('myextension');



$result = unserialize($cache->get($cacheIdentifier));



if ($result !== false ) {

    DebuggerUtility::var_dump($result);

} else {

    $result = $this->postRepository->findByTopic($topic->getUid(), $page, $itemsPerPage);

    $cache->set($cacheIdentifier, serialize($result), ['tag1', 'tag2']);

    DebuggerUtility::var_dump($result);

}

The first time the page with the action gets loaded all is ok and the entry has been made in de database (cf_myextension and cf_myextension_tags}.

But the 2nd time the cache gets loaded and I get an error. Even DebuggerUtility::var_dump($result); does not work:

Call to a member function map() on null    

in ../typo3/sysext/extbase/Classes/Persistence/Generic/QueryResult.php line 96



*/

protected function initialize()

{

    if (!is_array($this->queryResult)) {

        $this->queryResult = $this->dataMapper->map($this->query->getType(), $this->persistenceManager->getObjectDataByQuery($this->query));

    }

}



/**

A normal var_dump works and spits out the cache entry. What is the problem? Do I forget something? Can't a QueryResult together with some other variables not be stored as an array in the cache? I also tried VariableFrontend cache, which produced the same error.