Show info page after successful logout, including a link to the passed service url

src/main/java/org/keycloak/protocol/cas/CASLoginProtocol.java

@@ -5,6 +5,7 @@ import org.jboss.logging.Logger;
 import org.keycloak.common.util.KeycloakUriBuilder;
 import org.keycloak.events.EventBuilder;
 import org.keycloak.events.EventType;
+import org.keycloak.forms.login.LoginFormsProvider;
 import org.keycloak.models.*;
 import org.keycloak.protocol.LoginProtocol;
 import org.keycloak.protocol.cas.utils.LogoutHelper;
@@ -33,6 +34,8 @@ public class CASLoginProtocol implements LoginProtocol {
     public static final String SERVICE_TICKET_PREFIX = "ST-";
     public static final String SESSION_SERVICE_TICKET = "service_ticket";
 
+    public static final String LOGOUT_REDIRECT_URI = "CAS_LOGOUT_REDIRECT_URI";
+
     protected KeycloakSession session;
     protected RealmModel realm;
     protected UriInfo uriInfo;
@@ -131,9 +134,17 @@ public class CASLoginProtocol implements LoginProtocol {
 
     @Override
     public Response finishLogout(UserSessionModel userSession) {
+        String redirectUri = userSession.getNote(CASLoginProtocol.LOGOUT_REDIRECT_URI);
+
         event.event(EventType.LOGOUT);
         event.user(userSession.getUser()).session(userSession).success();
-        return Response.ok().build();
+        LoginFormsProvider infoPage = session.getProvider(LoginFormsProvider.class).setSuccess("Logout successful");
+        if (redirectUri != null) {
+            infoPage.setAttribute("pageRedirectUri", redirectUri);
+        } else {
+            infoPage.setAttribute("skipLink", true);
+        }
+        return infoPage.createInfoPage();
     }
 
     @Override

src/main/java/org/keycloak/protocol/cas/endpoints/LogoutEndpoint.java

@@ -5,13 +5,18 @@ import org.jboss.resteasy.annotations.cache.NoCache;
 import org.jboss.resteasy.spi.HttpRequest;
 import org.keycloak.common.ClientConnection;
 import org.keycloak.events.EventBuilder;
+import org.keycloak.models.ClientModel;
 import org.keycloak.models.KeycloakSession;
 import org.keycloak.models.RealmModel;
 import org.keycloak.models.UserSessionModel;
 import org.keycloak.protocol.cas.CASLoginProtocol;
+import org.keycloak.protocol.oidc.utils.RedirectUtils;
+import org.keycloak.services.ErrorPage;
 import org.keycloak.services.managers.AuthenticationManager;
+import org.keycloak.services.messages.Messages;
 
 import javax.ws.rs.GET;
+import javax.ws.rs.QueryParam;
 import javax.ws.rs.core.Context;
 import javax.ws.rs.core.HttpHeaders;
 import javax.ws.rs.core.Response;
@@ -37,6 +42,8 @@ public class LogoutEndpoint {
 
     private RealmModel realm;
     private EventBuilder event;
+    private ClientModel client;
+    private String redirectUri;
 
     public LogoutEndpoint(RealmModel realm, EventBuilder event) {
         this.realm = realm;
@@ -45,18 +52,36 @@ public class LogoutEndpoint {
 
     @GET
     @NoCache
-    public Response logout() {
+    public Response logout(@QueryParam(CASLoginProtocol.SERVICE_PARAM) String service) {
+        checkClient(service);
 
         AuthenticationManager.AuthResult authResult = AuthenticationManager.authenticateIdentityCookie(session, realm, false);
         if (authResult != null) {
             UserSessionModel userSession = authResult.getSession();
             userSession.setNote(AuthenticationManager.KEYCLOAK_LOGOUT_PROTOCOL, CASLoginProtocol.LOGIN_PROTOCOL);
+            if (redirectUri != null) userSession.setNote(CASLoginProtocol.LOGOUT_REDIRECT_URI, redirectUri);
 
             logger.debug("Initiating CAS browser logout");
             Response response =  AuthenticationManager.browserLogout(session, realm, authResult.getSession(), uriInfo, clientConnection, headers);
             logger.debug("finishing CAS browser logout");
             return response;
         }
-        return Response.ok().build();
+        return ErrorPage.error(session, Messages.FAILED_LOGOUT);
+    }
+
+    private void checkClient(String service) {
+        if (service == null) {
+            return;
+        }
+
+        client = realm.getClients().stream()
+                .filter(c -> CASLoginProtocol.LOGIN_PROTOCOL.equals(c.getProtocol()))
+                .filter(c -> RedirectUtils.verifyRedirectUri(uriInfo, service, realm, c) != null)
+                .findFirst().orElse(null);
+        if (client != null) {
+            redirectUri = RedirectUtils.verifyRedirectUri(uriInfo, service, realm, client);
+
+            session.getContext().setClient(client);
+        }
     }
 }