public function exec($resourceUrl, $postString = '')
    {
        $url = UrlBuilder::buildApiUrl($resourceUrl);
        $headers = $this->getHttpHeaders();
        $postString = $this->filePathToUpload ? $this->postFileData : $postString;

        $result = $this
            ->httpClient
            ->execute($url, $postString, $headers);

        $this->setTokenFromCookies();

        $this->filePathToUpload = null;

        return $result;
    }