Sometimes it may be useful to know how many sessions are active on you cherrypy server. For example you may wish to limit the number of simultaneous logins.

To get the current number of sessions use

len(cherrypy.session.cache)

For example you might use

class website(object):
    def login(self, user, pass):
        if len(cherrypy.session.cache) > 42:
            return "Sorry to many active users"
        else:
            # log in code

The count does not include a new session that was created during the current request.

Note this may only work when using a RAM session.

http://www.cherrypy.org/ticket/717 has a patch to cherrypy that allows use of len() on the session object.