if (isLoginRequired()) {
            return redirectToLogin();
        }

        final Map<String, Object> doc =
                searchHelper.getDocumentByDocId(form.docId, queryFieldConfig.getResponseFields(), getUserBean()).orElse(null);
        final String url = DocumentUtil.getValue(doc, fessConfig.getIndexFieldThumbnail(), String.class);

        if (isLoginRequired()) {
            return redirectToLogin();
        }

        Map<String, Object> doc = null;
        try {
            doc = searchHelper.getDocumentByDocId(form.docId, queryFieldConfig.getCacheResponseFields(), getUserBean()).orElse(null);
        } catch (final Exception e) {
            logger.warn("Failed to request: {}", form.docId, e);
        }
        if (doc == null) {

        if (isLoginRequired()) {
            return redirectToLogin();
        }

        Map<String, Object> doc = null;
        try {
            doc = searchHelper.getDocumentByDocId(form.docId,
                    new String[] { fessConfig.getIndexFieldUrl(), fessConfig.getIndexFieldConfigId() }, getUserBean()).orElse(null);
        } catch (final Exception e) {