public function getAtomURL()
    {
        $atomURL = null;

        $searchQuery = $this->searchQueryWithEqualsAndWildcard(' ', '*', true);
        if ($searchQuery) {
            $searchQuery = urlencode($searchQuery);

            $atomBaseURL = GeneralUtility::getIndpEnv('TYPO3_SITE_URL') . 'opac.atom?q=';
            $atomURL = $atomBaseURL . $searchQuery;
        }

        return $atomURL;
    }