protected function extractZip($file)
    {
        $tempFolder = sys_get_temp_dir().'/'.md5(rand(0, 99999));
        if (@mkdir($tempFolder) === false) {
            throw new ImportException('Impossible to create a temp folder for zip extraction');
        }
        $zip = new \ZipArchive();
        $zip->open($file->getRealPath());
        $zip->extractTo($tempFolder);
        $zip->close();

        return $tempFolder;
    }