[Seaside] scriptaculous - updater

[Ramon Leon]

> This I find interesting.  Doesn't this mean that if one 
> wanted, one could make the expiration cache extremely low 
> (e.g. like 30 seconds) and use something like this to ensure 
> people who keep their browser open don't lose the session, 
> while not having to waste space on sessions for people who 
> have already surfed away from the site?  And it should be 
> fairly simple to make a hidden field in normal html (i.e. not
> javascript) that does this autoupdate transparently (well, 
> the user will see a little blue reload every 10 seconds or 
> so) to support users who don't have javascript enabled?
> 
> Of course it isn't quite this simple.  The reason the session 
> isn't getting updates may be that the user is surfing a 
> different part of the site and will come back later via the 
> back button.  But with a little work I think something like 
> this would be possible.  Right?

Yup, I do this for exactly that reason, though I still keep a 10 minute
timeout.  As long as the browser stays open, the session remains active.
You don't even need to render anything to the client.

renderSessionKeepAliveOn: html 
    html script: ((html periodical)
        frequency: (self preferenceAt: #sessionExpirySeconds) - 20;
        callback: [Transcript show: 'session touch'; cr];
        yourself)

Ramon Leon
http://onsmalltalk.com