public function getItem($cache, $key)
    {
        $cache = self::encodeCache($cache);
        $key = self::encodeKey($key);
        $url = "projects/{$this->project_id}/caches/$cache/items/$key";

        $this->setJsonHeaders();
        try {
            $res = $this->apiCall(self::GET, $url);
        } catch (Http_Exception $e) {
            if ($e->getCode() == Http_Exception::NOT_FOUND) {
                return null;
            } else {
                throw $e;
            }
        }
        return self::json_decode($res);
    }