public function cmdGetCache()
    {
        $id = $this->getParam(0);

        if (empty($id)) {
            $this->errorAndExit($this->text('Invalid command'));
        }

        $result = $this->cache->get($id);

        if (!isset($result)) {
            $this->errorAndExit($this->text('Unexpected result'));
        }

        $this->outputFormat($result, 'json');
        $this->output();
    }