protected function callApi($queryString, $postData = null)
    {
        $this->setPostData($postData);

        $url = $this->apiUrl . '?' . $queryString . '&format=php';

        curl_setopt($this->curl, CURLOPT_URL, $url);

        $response = curl_exec($this->curl);
        $responseCode = curl_getinfo($this->curl, CURLINFO_HTTP_CODE);

        if (200 !== $responseCode) {
            throw new BuildException('Wiki webapi call failed (http response ' . $responseCode . ')');
        }

        $result = @unserialize($response);
        if (false === $result) {
            throw new BuildException('Couldn\'t unserialize Wiki webapi response');
        }

        return $result;
    }