docs: @SneakyThrows
      private static String getRelativeRedirectUrlFor(final WsFederationConfiguration config, final Service service, final HttpServletRequest request) {
          val builder = new URIBuilder(WsFederationNavigationController.ENDPOINT_REDIRECT);
          builder.addParameter(WsFederationNavigationController.PARAMETER_NAME, config.getId());
          if (service != null) {
              builder.addParameter(CasProtocolConstants.PARAMETER_SERVICE, service.getId());
          }
          val method = request.getParameter(CasProtocolConstants.PARAMETER_METHOD);
          if (StringUtils.isNotBlank(method)) {
              builder.addParameter(CasProtocolConstants.PARAMETER_METHOD, method);
          }
          return builder.toString();
      }