Consolidating Cache Management in Zend Framework

In version 1.10, Zend added an Application Resource to the Zend Framework for easily setting up your Caching resources through configuration files.

resources.cachemanager.cacheCoreFile.frontend.name = "Core"
resources.cachemanager.cacheCoreFile.frontend.options.lifetime = 3600
resources.cachemanager.cacheCoreFile.frontend.options.cache_id_prefix = APPLICATION_ENV "_cache_core_file"
resources.cachemanager.cacheCoreFile.frontend.options.automatic_serialization = true
resources.cachemanager.cacheCoreFile.frontend.options.automatic_cleaning_factor = 1
resources.cachemanager.cacheCoreFile.backend.name = "File"
resources.cachemanager.cacheCoreFile.backend.options.cache_dir = APPLICATION_PATH "/data/cache"

The problem is that components like Doctrine, Zend_Translate, Zend_Db and so on all have directives for their own cache configurations.

This makes managing cache times, invalidations, and timeouts very difficult.

A solution to this is to use the cachemanger to create your cache then pass that cache onto your other components through the bootstrap ( see example below ).

class Bootstrap extends Zend_Application_Bootstrap_Bootstrap {
  ...
  $this->_cache = null;
  protected function _initCache() {
    $this->bootstrap('cachemanager');
    $cache = $this->getResource('cachemanager')
        ->getCache('cacheCoreFile');
    $this->_cache = $cache;
    Zend_Registry::set('cacheCoreFile', $cache);
  }

  protected function _initTranslateCache() {
    $this->bootstrap('cache');
    $this->bootstrap('translate');
    Zend_Translate::setCache($this->_cache);
  }

  protected function _initDoctrineCache() {
    $this->bootstrap('cache');
    $this->bootstrap('doctrine');
    $doctrineAdapter = new DoctrineAdapter(
        $this->_cache
        , 'my_doctrine_cache_prefix'
    );
    $manager = Doctrine_Manager::getInstance()
    $manager->setAttribute(
      Doctrine_Core::ATTR_RESULT_CACHE
      , $doctrineAdapter
    );
  }
  ...
}

Most of the Zend components are pretty straight forward in that they accept an instance of Zend_Cache. Doctrine on the other hand defines it's own cache drivers. Thanks to Benjamin Steininger we have a Doctrin_Cache driver implementation for Zend_Cache.

I made a small modification to the "save" method to add some custom cache tags, which I'll explain in a minute.

class DoctrineAdapter implements Doctrine_Cache_Interface {
  ...
  public function save($id, $data, $lifetime = false) {
    $id = $this->_prefix . $id;
    return $this->_cache->save(
      $data
      , $id
      , array(
        My_CacheTags::TAG_DOCTRINE
      )
      , $lifetime
    );
  }
  ...
}

Zend_Cache tags allow for "categorizing" of cached items.

To make my tag management easier I created a class with all the tags I use as static properties. This also allows me to reflect on the class for building my cache admin interfaces.

class My_CacheTags {
  const TAG_MODULE_DEFAULT = "TAG_MODULE_DEFAULT";
  const TAG_MODULE_OTHER = "TAG_MODULE_OTHER";
  const TAG_ACTION = "TAG_ACTION";
  const TAG_VIEW = "TAG_VIEW";
  const TAG_DOCTRINE = "TAG_DOCTRINE";
  // Zend Translate automatically adds it's tag Zend_Translate so we'll use it's tag name
  const TAG_TRANSLATE = "Zend_Translate";
}

Now, emptying specific groups of items from the cache is much easier since we can specify which tags I want to clean from the cache.

$cache->clean(
  Zend_Cache::CLEANING_MODE_MATCHING_TAG,
  array(
    My_CacheTags::TAG_MODULE_DEFAULT
    , My_CacheTags::TAG_VIEW
  )
);

The set-up described gives me much better insite as to how my application is configured, allows for easier changes and managing my cache is much simpler.