On 1/23/07, Will McCutchen <[EMAIL PROTECTED]> wrote: ... > I would add option #5: Write a custom middleware component to update a > last_accessed attribute for logged in users on every request. > > http://www.djangobook.com/en/beta/chapter16/
If you have a lot of requests, I doubt you really want to update a table on every request. Hitting the DB is somewhat expensive; re-pickling a session on top of that is pretty pricey. The attached file implements a (lightly-tested) middleware. It makes a dictionary keyed by datetime down to an even minute. The value is a Set of user_id's seen that minute. This dict is updated by a request middleware. The dict has keys for ONLINE_MINUTES (the number of minutes you consider a user to be "online") + 1 minutes. Every ONLINE_MINUTES * PURGE_MULTIPLE minutes, it removes old minute keys from the dictionary. This allows fast updating no matter how many users you have, fast counting, and fast eviction. A downside is that it Includes partial minutes (i.e. 2 minutes would count up to users seen in 2:59, due to minute rollover); I think this amount of slop is probably OK given the reduction in maintenance cost. ;-) You'll want to use OnlineUsers.get_online_user_ids() wherever you need the list of IDs. If you have multiple web servers, this problem gets more complicated -- then you probably need to use the DB or some shared process. Please test it out and tell me if it works. If you need to -list- users rather than count them, you may wish to keep usernames or user objects rather than user_id's. That's a pretty straight-forward change if you want it. Let me know if it's useful; I can post it somewhere for others... --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "Django users" group. To post to this group, send email to [email protected] To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/django-users?hl=en -~----------~----~----~----~------~----~------~--~---
OnlineUsers.py
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