How to detect when sessions expire in asp.net?

Question

I want to track if users loout or their session expire. I need to k now exactly when their session expired (within +/- 5 min). Right now if a users leaves the page open in the browser and returns after a day, I will know it expired when he tries to do something after a day- but in reality the session expired after say an hour of inactivity.

I want to have a script run every 5 minutes on the server and check which sessions are expired and detect them and then log the expiration time in a db. How do I have a script run continuously with such short intervals on the server? What exactly does the script do? Is there a better way to do this?

Why would you want to do this? – Lazarus Feb 02 '11 at 13:47 — Lazarus, Feb 02 '11 at 13:47

score 10 · Answer 1 · edited May 23 '17 at 11:47

10

In your global.asax, you can capture the Session_End event. See this question for further details:

How to handle session end in global.asax?

Note that a five minute timeout is not easily possible, since you have to wait for the session to expire (= usually 20 min.) before you can detect the inactivity. Thus, if you really need the short interval, you'd need to

reduce the Session timeout to five minutes.

On the other hand, you also need to

make sure that five minutes of inactivity with an open browser does not cause the session to be abandoned (unless you want your users to lose their session when they leave the computer to get a cup of coffee). Such an "automatic keepalive" can be implemented, for example, by using JavaScript.

edited May 23 '17 at 11:47

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answered Feb 02 '11 at 13:47

Heinzi

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This only works if the SessionState is set to InProc. Another SO question with different details: http://stackoverflow.com/questions/1262867/session-end-code-on-browser-close – Joel Etherton Feb 02 '11 at 13:55
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Might also be worth noting that if you check for the existence of a Session it will reset it's timeout timer if it exists... – hunter Feb 02 '11 at 13:55
@hunter, any more info on this? :-) – IrishChieftain Feb 02 '11 at 14:50
@hunter yeah, I wasn't aware of it being reset – IrishChieftain Feb 02 '11 at 15:07
If you touch an item in the Session and it is set to expire it will reset it's timer. Checking if it `== null` will cause it to reset. – hunter Feb 02 '11 at 15:21

How to detect when sessions expire in asp.net?

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