Is it possible to intercept ProcessRequest to determine forms timeout before GetControllerInstance is called?

In an ASP.NET MVC application when using a custom Dependency Injection container (in this case, Unity), is it possible to intercept a request before GetControllerInstance is called to determine if forms authentication timeout has occurred?

I have the following in web.config:

<authentication mode="Forms">
  <forms loginUrl="~/Home/Index" timeout="10" defaultUrl="~/Home/Index"/>
</authentication>

If I log in to the website, wait for the timeout to occur, and then access another page (well, controller action), I would have expected the framework to take care of automatically redirecting me to ~/Home/Index. Instead it merrily goes along trying to create the new controller to handle the request which fails and I end up being redirected to our custom error page.

Looking at the callstack, I would think this needs to happen somewhere around MvcHandler.System.Web.IHttpHandler.ProcessRequest or MvcHandler.ProcessRequest .. certainly before DefaultControllerFactory.CreateController is called.

Has anyone else had to handle this situation?

Update: To be honest, I think this approach is p开发者_开发技巧robably incorrect and the better idea is to handle forms authentication timeout on the client-side with some javascript on the master page. I could then redirect to an action that will clear the session and return them to the login page similar to what is described here.

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You could write a controller factory that wraps the unity controller factory (see my post on delegating decorators http://haacked.com/archive/2008/06/18/delegating-decorators.aspx for an example).

Then in your controller factory, you can override GetControllerInstance and wrap the delegate's call to GetControllerInstance with your before and after code.

Does that make sense?