[keycloak-user] Spring Security Adapter: Set locale on redirect to login page + Link back to application from login form

Hello everyone, 1. Set locale on redirect: We have a multilingual application where you can choose your locale. The login entry point then looks like https://localhost:8443/en_US/login.html Now I need to tell Keycloak which locale to use. The way I realized it isn't really clean: I'm extending from KeycloakWebSecurityConfigurerAdapter and overriding the keycloakAuthenticationProcessingFilter method in order to instantiate my own authentication processing filter implementation: @Bean @Override protected KeycloakAuthenticationProcessingFilter keycloakAuthenticationProcessingFilter() throws Exception { RequestMatcher requestMatcher = new OrRequestMatcher(new AntPathRequestMatcher("/*/login.html"), new RequestHeaderRequestMatcher(KeycloakAuthenticationProcessingFilter.AUTHORIZATION_HEADER)); KeycloakAuthenticationProcessingFilter filter = new LocaleAwareKeycloakAuthenticationProcessingFilter(keycloakAuthenticationManager(), requestMatcher); filter.setSessionAuthenticationStrategy(sessionAuthenticationStrategy()); return filter; } The custom authentication processing filter is the following: public class LocaleAwareKeycloakAuthenticationProcessingFilter extends KeycloakAuthenticationProcessingFilter implements ApplicationContextAware { private final Logger log = LogManager.getLogger(getClass()); private ApplicationContext applicationContext; private AdapterDeploymentContext adapterDeploymentContext; private AdapterTokenStoreFactory adapterTokenStoreFactory = new SpringSecurityAdapterTokenStoreFactory(); public LocaleAwareKeycloakAuthenticationProcessingFilter(AuthenticationManager authenticationManager, RequestMatcher requiresAuthenticationRequestMatcher) { super(authenticationManager, requiresAuthenticationRequestMatcher); } @Override public void afterPropertiesSet() { super.afterPropertiesSet(); adapterDeploymentContext = applicationContext.getBean(AdapterDeploymentContext.class); } @Override public Authentication attemptAuthentication(HttpServletRequest request, HttpServletResponse response) { log.debug("Attempting Keycloak authentication"); HttpFacade facade = new SimpleHttpFacade(request, response); KeycloakDeployment deployment = adapterDeploymentContext.resolveDeployment(facade); AdapterTokenStore tokenStore = adapterTokenStoreFactory.createAdapterTokenStore(deployment, request); RequestAuthenticator authenticator = new LocaleAwareRequestAuthenticator(facade, request, deployment, tokenStore, -1); AuthOutcome result = authenticator.authenticate(); log.debug("Auth outcome: {}", result); if (AuthOutcome.FAILED.equals(result)) { throw new KeycloakAuthenticationException("Auth outcome: " + result); } else if (AuthOutcome.AUTHENTICATED.equals(result)) { Authentication authentication = SecurityContextHolder.getContext().getAuthentication(); Assert.notNull(authentication, "Authentication SecurityContextHolder was null"); return getAuthenticationManager().authenticate(authentication); } else { AuthChallenge challenge = authenticator.getChallenge(); if (challenge != null) { challenge.challenge(facade); } return null; } } @Override public void setApplicationContext(ApplicationContext applicationContext) { super.setApplicationContext(applicationContext); this.applicationContext = applicationContext; } @Override public void setAdapterTokenStoreFactory(AdapterTokenStoreFactory adapterTokenStoreFactory) { super.setAdapterTokenStoreFactory(adapterTokenStoreFactory); this.adapterTokenStoreFactory = adapterTokenStoreFactory; } } The custom request authentication is the following: public class LocaleAwareRequestAuthenticator extends SpringSecurityRequestAuthenticator { public LocaleAwareRequestAuthenticator(HttpFacade facade, HttpServletRequest request, KeycloakDeployment deployment, AdapterTokenStore tokenStore, int sslRedirectPort) { super(facade, request, deployment, tokenStore, sslRedirectPort); } @Override protected OAuthRequestAuthenticator createOAuthAuthenticator() { return new LocaleAwareOAuthRequestAuthenticator(this, facade, deployment, sslRedirectPort, tokenStore); } } And finally the LocaleAwareOAuthRequestAuthenticator is the following: public class LocaleAwareOAuthRequestAuthenticator extends OAuthRequestAuthenticator { public LocaleAwareOAuthRequestAuthenticator(RequestAuthenticator requestAuthenticator, HttpFacade facade, KeycloakDeployment deployment, int sslRedirectPort, AdapterSessionStore tokenStore) { super(requestAuthenticator, facade, deployment, sslRedirectPort, tokenStore); } @Override protected String getRedirectUri(String state) { String redirect = super.getRedirectUri(state); if (redirect == null) { return null; } // getting the locale from our relative path and appending to the redirect uri String url = facade.getRequest().getRelativePath(); return redirect + "&kc_locale=" + ServletUtils.getLocaleFromURL(url).getLanguage(); } } As you can see I had to override many methods and had to duplicate much code. Is there really no other way to set the locale when redirecting to the login page? --- 2. Link back to application And another problem I had to fight with: We only use the login page from Keycloak. All other stuff should happen in our application as there are some processes we don't want to copy. As we use a custom user storage provider which accesses the external db from our application this isn't a problem. I had to make some template in order to set the URLs to link to our password reminder and registering pages. In this case I'm using "${client.baseUrl}/${.locale}" as base URL to link back to pwreminder.html and register.html. As ${client.baseUrl} isn't a mandatory field in the Keycloak Admin Console this isn't a clean way as well. But there's no ${client.rootUrl} to access. So this is the only chance to unsafely link back to our application. Why the client root url isn't accessible in the templates? Any good reason not to add it to the template data model? --- If good solutions for those problems need to be implemented I'll take a look at the code, opening issues and providing a pull requests on GitHub.