public static void putUnauthorizedRedirectUrlIntoFlowScope(final RequestContext context, final URI url) {
        context.getFlowScope().put(PARAMETER_UNAUTHORIZED_REDIRECT_URL, url);
    }
Adds the unauthorized redirect url to the flow scope.

@param context the request context
@param url     the uri to redirect the flow
core/cas-server-core-web-api/src/main/java/org/apereo/cas/web/support/WebUtils.java