{"id":142,"date":"2026-11-06T08:00:00","date_gmt":"2026-11-06T07:00:00","guid":{"rendered":"https:\/\/hoja.in\/blog\/?p=142"},"modified":"2026-10-16T14:00:13","modified_gmt":"2026-10-16T12:00:13","slug":"using-the-typo3-caching-framework-in-your-own-extension","status":"publish","type":"post","link":"https:\/\/hoja.in\/blog\/using-the-typo3-caching-framework-in-your-own-extension\/","title":{"rendered":"Using the TYPO3 caching framework in your own extension"},"content":{"rendered":"

Here is a situation I have seen more than once. An extension shows data from an external service, for example opening hours or events from a city API. The plugin is USER_INT<\/code> because “the data must be fresh”, and every page view makes an HTTP call. The external service answers in one or two seconds on a good day. On a bad day the whole page waits.<\/p>\n

The fix is not to make the page cached and hope. The fix is to cache the expensive part, the API answer, with the TYPO3 caching framework. It has been in the core since 4.3, and it is still one of the most underused APIs in extensions I review.<\/p>\n

Step 1: register the cache<\/h2>\n

A cache is a frontend (how values are stored: VariableFrontend<\/code> for any serializable PHP value, PhpFrontend<\/code> for PHP code) plus a backend (where they are stored). Register it in ext_localconf.php<\/code>:<\/p>\n

<?php\n\ndefined('TYPO3') or die();\n\n$GLOBALS['TYPO3_CONF_VARS']['SYS']['caching']['cacheConfigurations']['myext_feed'] ??= [];\n$GLOBALS['TYPO3_CONF_VARS']['SYS']['caching']['cacheConfigurations']['myext_feed']['groups'] ??= ['pages'];<\/code><\/pre>\n
That’s really all. When frontend and backend are not set, the CacheManager<\/code> uses VariableFrontend<\/code> with Typo3DatabaseBackend<\/code>. The ??=<\/code> is important: it lets the project override the configuration in config\/system\/additional.php<\/code> without fighting your extension.<\/p>\n
The groups<\/code> entry decides which “flush” actions clear your cache. Without it, the default group is all<\/code>. I put this cache in pages<\/code>, because its content is shown on pages and should be cleared together with the page cache. You will see in step 4 why this choice brings a nice bonus.<\/p>\n
With the database backend, TYPO3 needs two tables, cache_myext_feed<\/code> and cache_myext_feed_tags<\/code>. The Database Analyzer in the Install Tool or ddev typo3 extension:setup<\/code> creates them for you.<\/p>\n
Step 2: inject the cache<\/h2>\n
Don’t call GeneralUtility::makeInstance(CacheManager::class)->getCache()<\/code> all over the place. Define the cache as a service and inject it, just like the core does for cache.hash<\/code> or cache.pages<\/code>:<\/p>\n
# Configuration\/Services.yaml\nservices:\n  _defaults:\n    autowire: true\n    autoconfigure: true\n    public: false\n\n  VendorMyExt:\n    resource: '..\/Classes\/*'\n\n  cache.myext_feed:\n    class: TYPO3CMSCoreCacheFrontendFrontendInterface\n    factory: ['@TYPO3CMSCoreCacheCacheManager', 'getCache']\n    arguments: ['myext_feed']\n\n  VendorMyExtServiceFeedService:\n    arguments:\n      $cache: '@cache.myext_feed'<\/code><\/pre>\n
Instead of the last three lines you can also write #[Autowire(service: 'cache.myext_feed')]<\/code> in front of the constructor parameter. Several core classes do exactly that with cache.runtime<\/code>.<\/p>\n
Step 3: read, fetch, tag, store<\/h2>\n
<?php\n\ndeclare(strict_types=1);\n\nnamespace VendorMyExtService;\n\nuse TYPO3CMSCoreCacheFrontendFrontendInterface;\nuse TYPO3CMSCoreHttpRequestFactory;\n\nfinal readonly class FeedService\n{\n    public function __construct(\n        private FrontendInterface $cache,\n        private RequestFactory $requestFactory,\n    ) {}\n\n    \/**\n     * @param array{uid: int, url: string, lifetime: int} $feed record from tx_myext_feed\n     *\/\n    public function getItems(array $feed): array\n    {\n        $identifier = 'feed_' . $feed['uid'] . '_' . sha1($feed['url']);\n        $items = $this->cache->get($identifier);\n        if (is_array($items)) {\n            return $items;\n        }\n\n        try {\n            $response = $this->requestFactory->request($feed['url'], 'GET', ['timeout' => 3]);\n            $items = json_decode((string)$response->getBody(), true, 32, JSON_THROW_ON_ERROR);\n        } catch (Throwable) {\n            \/\/ Remember the failure for one minute, do not hammer a broken API\n            $this->cache->set($identifier, [], ['tx_myext_feed_' . $feed['uid']], 60);\n            return [];\n        }\n\n        $this->cache->set(\n            $identifier,\n            $items,\n            ['tx_myext_feed', 'tx_myext_feed_' . $feed['uid']],\n            $feed['lifetime'] ?: 3600\n        );\n        return $items;\n    }\n}<\/code><\/pre>\n
A few things that I learned the hard way:<\/p>\n