[Active4d-dev] Determining if session has expired?

[Brad Perkins]

In a site that uses sessions to track state data etc, if a user visits a 
page for the first time or comes back to that page after a lengthy interval 
it is desirable to display a page that presents itself as a new visit. 
However if a user comes back to that page shortly after their session has 
expired, you want to let them know so because their state data no longer is 
accessible.

One solution is to set a lengthy session expiration interval and not worry 
about it, but this has its downsides, especially in a high traffic site.

In my case, considering workflow, I'm envisioning users who will visit a 
site and actively work with the data with little time away, therefore a 
5-10 minute expiration seems reasonables.

I suppose I could update a "last_interaction_timestamp" cookie and examine 
this when a new session is created, but I don't want to have to rely on 
cookies being on.
Also in the system in question users will be anonymous (no login required) 
so I can't think of a reliable way to store this information in the database.

How have others approached this problem?
Thanks,
Brad Perkins ([EMAIL PROTECTED])
DOE ARM Program Tropical Western Pacific Office
Los Alamos National Laboratory
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