[Seaside] Implementing a session timeout counter

[jtuchel at objektfabrik.de]

Hi,


I'd like to present our users a countdown in the browser that shows the 
remaining time until the session times out.

The problems I see are not JavaScript timouts and stuff to make this 
thing count down. My problem is more related to how to keep the counter 
in sync with the server side timeout. I am not talking about msecs or 
such, but the fact that there are at least two things that reset the 
counter on the server side and that needs to be communicated to the 
client: one is every standard callback processing, the other is Ajax 
(and maybe in some applications we also have WebSockets involved).

I guess the best way to communicate the fact that the counter is back to 
(say) 40 minutes is to use an HTTP Header that gets added to every 
response, be it from some normal callback or Ajax callback. Do you guys 
agree?

If we agree so far, we'd have to add some javascript code to all our 
rendered pages that ask for that Header and reset/restart the countdown.

In case of complete-re-renders of a page this is probably something in 
the load script, right?

For Ajax, I'd use JQuery's .ajaxComplete() to do the same. I guess there 
is some way to access the headers and restart the timer.

Am I on the right track? Has anybody done this before? Maybe there 
already is something available in Seaside?


The next wish on our list would be a button that a user can press in 
order to keep the session alive without doing anything else. This, I 
think, would be easy by just sending a little ajax request to the server 
that does basically nothing. Everything else is implemented already when 
the above-mentioned steps are done... right?

Bonus question: Should the http header be filled with the end datetime 
of the session or the last tiome it was reset and to which value? In the 
former case, how can I determine it on the server, given I don't want to 
have the session timeout time in two places or a global


Thanks for your ideas and thoughts,


Joachim

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