How to catching the session expiry notification in Pharo Seaside 3.2? I need remove the user from de active user list when the session expiring.
You can subclass WASession and tell Seaside to use your session instead via the configuration (see WAApplicationConfiguration>>describeOn:). In your subclass implement #unregistered. This method will be executed when the session has expired (note that this may not happen immediately but only upon the next request to the same application as the this is triggered by the session cache).