public function request($url)
    {
        try {
            $resp = $this->guzzle->get($url);
            return (string) $resp->getBody();
        } catch (RequestException $e) {
            $response = $e->getResponse();
            throw new HttpException($response ? $response->getBody() : null, $e->getMessage(), $e->getCode(), $e);
        } catch (TransferException $e) {
            throw new HttpException('', $e->getMessage(), $e->getCode(), $e);
        }
    }