Application.php

<?php

class EtuDev_Zend_Application extends Zend_Application
{

    /**
     *
     * @var Zend_Cache_Core|null
     */
    protected $_configCache;

    public function __construct($environment, $options = null, Zend_Cache_Core $configCache = null)
    {
        $this->_configCache = $configCache;
        parent::__construct($environment, $options);
    }

    protected function _cacheId($file)
    {
        return 'appconfig_' . $this->getEnvironment() . '_' . sha1($file);
    }

    protected function _loadConfigCache()
    {
        $configCache = new Zend_Cache_Core(array('automatic_serialization' => true));

        if (extension_loaded('xcache')) {
            $backend_type = 'Xcache';
        } elseif (extension_loaded('apc')) {
            $backend_type = 'Apc';
        } elseif (extension_loaded('memcache')) {
            $backend_type = 'Memcached';
        } else {
            $backend_type = 'File';
        }

        $backend = Zend_Cache::_makeBackend($backend_type, array());

        $configCache->setBackend($backend);
        $this->_configCache = $configCache;
    }

    //Override
    protected function _loadConfig($file)
    {
        if (!$this->_configCache) {
            $this->_loadConfigCache();
        }
        $suffix = strtolower(pathinfo($file, PATHINFO_EXTENSION));
        if ($this->_configCache === null || $suffix == 'php' || $suffix == 'inc') { //No need for caching those
            return parent::_loadConfig($file);
        }

        $configMTime = filemtime($file);

        $cacheId = $this->_cacheId($file);

        //podemos quitar esto para acelerar, pero habría que borrar la cache manualmente en deploy entonces
        $cacheLastMTime = $this->_configCache->test($cacheId);
        if ($cacheLastMTime !== false && $configMTime < $cacheLastMTime) { //Valid cache?
            return $this->_configCache->load($cacheId, true);
        } else {
            $config = parent::_loadConfig($file);
            $this->_configCache->save($config, $cacheId);

            return $config;
        }
    }
}