How do you override the WCF AuthenticationService IsLoggedIn() method?

Question

I have three current thoughts on how to do this:

1. re-implement AuthenticationService, which uses lots of internal constructors and internal helpers,
2. implement custom IIdentity and IPrincipal types and somehow hook these into FormsAuthentication.
3. give up and roll my own.

The problem is that we've got web apps and fat client apps using authentication and storing cookies. However, logging out of a web app does not log out of a fat client app, and we have now way of forcing a refreshed cookie, atm.

Answer 1

Found what I needed. Use number 2, implement my own IIdentity, and then implement the FormsAuthentication_OnAuthenticate on Global.asax [1].

[1] http://msdn.microsoft.com/en-us/library/system.web.security.formsauthenticationmodule.aspx