The code is available on my Github: https://github.com/shenghuahe/zf2-cache-mvc-response

Configuration

The filesystem cache is configured within Application/module.config.php and therefore delegated to ZendCacheServiceStorageCacheAbstractServiceFactory to construct the Cache Adapter.

Response Caching

The caching for the MVC response is done through event listeners. This is for separating the concerns and making the code much better decoupled and reusable.

Check out the two methods loadPageCache() and savePageCache() within Application/Module.php

savePageCache() is attached to the MvcEvent::EVENT_RENDER event with a very low priority. This makes sure $e->getResponse()->getContent() is populated before adding it to the cache.

loadPageCache() is attached to the MvcEvent::EVENT_ROUTE event with a low priority. This allows all other attached events to run first before loading the response data cache. If the response data is within the cache, $e->getResponse()->setContent() will be called and the response object will be returned. This stops all subsequent listeners attached to the same event from executing. You might wonder why the savePageCache() method no longer gets ran either, and that’s attached to a different event (EVENT_RENDER). The trick is actually done within ZendMvcApplication::run() by the following block of code:

$result = $events->trigger(MvcEvent::EVENT_ROUTE, $event, $shortCircuit);
    if ($result->stopped()) {
        $response = $result->last();
        if ($response instanceof ResponseInterface) {
            $event->setTarget($this);
            $event->setResponse($response);
            $events->trigger(MvcEvent::EVENT_FINISH, $event);
            $this->response = $response;
            return $this;
        }
    }

You can see the $result->stopped() returns true in this case and the $result object is an instance of ZendEventManagerResponseCollection. The last result is the response object with the data retrieved from the cache!