writeHeaders(response);
                final String responseContentType = curlResponse.getHeaderValue("Content-Type");
                if (StringUtil.isBlank(responseContentType)) {
                    response.setHeader("Content-Type", "application/json");
                } else {
                    response.setHeader("Content-Type", responseContentType);
                }

                if (resultsPerPage instanceof Integer) {
                    form.num = (Integer) resultsPerPage;
                }
            }
        }

        if (StringUtil.isBlank(form.q) && form.fields.isEmpty() && !form.hasConditionQuery()) {
            // redirect to index page
            form.q = null;
            return redirectToRoot();
        }

        try {

            init();
        }

        final String virtualHostKey = ComponentUtil.getVirtualHostHelper().getVirtualHostKey();
        final List<LabelTypeItem> labelList;
        if (StringUtil.isBlank(virtualHostKey)) {
            labelList =
                    labelTypeItemList.stream().filter(item -> matchLocale(requestLocale, item.getLocale())).collect(Collectors.toList());
        } else {

        if (config == null) {
            return OptionalThing.empty();
        }
        final String pipeline = config.getConfigParameterMap(ConfigName.CONFIG).get(Config.PIPELINE);
        if (StringUtil.isBlank(pipeline)) {
            return OptionalThing.empty();
        }
        return OptionalThing.of(pipeline);
    }

    public void refresh() {
        crawlingConfigCache.invalidateAll();
    }

            if (f.equals(field)) {
                return true;
            }
        }
        return false;
    }

    public boolean isFacetField(final String field) {
        if (StringUtil.isBlank(field)) {
            return false;
        }
        boolean flag = false;
        for (final String f : facetFields) {
            if (field.equals(f)) {
                flag = true;
            }

    protected String crawlingConfigInternal(final CrawlingConfigForm form) {

        String configName = form.crawlingConfigName;
        String configPath = form.crawlingConfigPath.trim();
        if (StringUtil.isBlank(configName)) {
            configName = StringUtils.abbreviate(configPath, 30);
        }

        // normalize
        final StringBuilder buf = new StringBuilder(1000);

        // TODO use cache
    }

    @Override
    public boolean visited(final EsUrlQueue urlQueue) {
        final String url = urlQueue.getUrl();
        if (StringUtil.isBlank(url)) {
            if (logger.isDebugEnabled()) {
                logger.debug("URL is a blank: {}", url);
            }
            return false;
        }

        final String loginUrl = replaceCredentials(credentials, originalLoginUrl);
        final String loginReqParams = replaceCredentials(credentials, getParameter(LOGIN_PARAMETERS));

        if (StringUtil.isBlank(loginUrl)) {
            if (logger.isDebugEnabled()) {
                logger.debug("No login.url");
            }
            return;
        }

        final HttpUriRequest httpRequest;

            urlQueueService.offerAll(crawlerContext.sessionId, childList);
        }
    }

    protected boolean isValid(final UrlQueue<?> urlQueue) {
        if ((urlQueue == null) || StringUtil.isBlank(urlQueue.getUrl())
                || (crawlerContext.getMaxDepth() >= 0 && urlQueue.getDepth() > crawlerContext.getMaxDepth())) {
            return false;
        }

        // url filter

        }
    }

    protected List<String> getDefaultGroupList() {
        final String value = ComponentUtil.getFessConfig().getSystemProperty("aad.default.groups");
        if (StringUtil.isBlank(value)) {
            return Collections.emptyList();
        }
        return split(value, ",").get(stream -> stream.filter(StringUtil::isNotBlank).map(String::trim).collect(Collectors.toList()));
    }