how to list all sessions?

I have created ActiveRecord session store in a rails 3 project:

rake db:sessions:create rake db:migrate

then

Myapp::Application.config.session_store :active_record_store, :key => '_myapp_session'

in initializers/session_store.rb and it all works.

Now the question: how do I list ALL active sessions?

If you want to be completely accurate you can't: you'll have a row corresponding to a particular session, but you can't tell if that person has since quit their browser. Or they could still have your site open but not actually be sitting at their computer. If you sessions table has an updated_at column you will get when their session last changed which is probably a reasonable approximation. Why do you care?

Fred

Imagine a chat room, where all (more or less) active users are listed. I don't need them to log in, and I don't care if they quit the browser, a background worker would purge inactive sessions. I also understand that I can query the "sessions" table, I was just wondering if there is a more abstracted way of doing this in Rails.