private void handleInitialAuthenticationRequest(
        final WSFederationRequest fedRequest,
        final HttpServletResponse response,
        final HttpServletRequest request) throws Exception {

        val targetService = createService(fedRequest);
        val registeredService = findAndValidateFederationRequestForRegisteredService(targetService, fedRequest);
        LOGGER.debug("Redirecting to identity provider for initial authentication [{}]", fedRequest);
        redirectToIdentityProvider(fedRequest, response, request, targetService, registeredService);
    }
Handle federation request.

@param response the response
@param request  the request
@throws Exception the exception
support/cas-server-support-ws-idp/src/main/java/org/apereo/cas/ws/idp/web/WSFederationValidateRequestController.java