Rails - List of active sessions

Question

Hi there,

I am trying to figure out the most straightforward and safe way to count the number of active sessions using a memcached storage option. With DB based session storage, I can just count the number of rows in the table but can't do the same thing with memcached.

Thanks, Vikram

Answer 1

I don't think you can do that with memcache.

Must admit I am yet to use MemCacheStore but you could probably implement something using before filters in the application controller with a cron job and a table in your database.

Answer 2

Memcache explicitly does not provide a way to iterate over the keys in use. You can read or write based on a specific key, but you can not get a list of all keys or iterate over them. This is a limitation of memcache.

Unfortunately, a before_filter won't work because sessions can be expired in memcached without your app being notified about it.

Why do you want to get this information?