}
        final SearchHelper searchHelper = ComponentUtil.getSearchHelper();
        final FessConfig fessConfig = ComponentUtil.getFessConfig();

        if (!fessConfig.isAcceptedSearchReferer(request.getHeader("referer"))) {
            writeJsonResponse(HttpServletResponse.SC_BAD_REQUEST, escapeJsonKeyValue(MESSAGE_FIELD, "Referer is invalid."));
            return;
        }

        if (!fessConfig.isApiSearchScroll()) {

     *
     * @param request the HTTP servlet request
     * @return the client IP address
     */
    public String getClientIp(final HttpServletRequest request) {
        final String value = request.getHeader("x-forwarded-for");
        if (StringUtil.isNotBlank(value)) {
            return value;
        }
        return request.getRemoteAddr();
    }

    /**