protected String getUserCodeFromRequest(final HttpServletRequest request) {
        final FessConfig fessConfig = ComponentUtil.getFessConfig();
        final String userCode = request.getParameter(fessConfig.getUserCodeRequestParameter());
        if (StringUtil.isBlank(userCode)) {
            return null;
        }

        if (fessConfig.isValidUserCode(userCode)) {
            request.setAttribute(Constants.USER_CODE, userCode);