Flex:how to count online user and record user visits?

Question

Hey guys,

I want to write a module that count online user and record user visits.

I'm using Cairngorm,it seems to me when user open the Application,I should dispatch an event,and increase onlineCount stored in ModelLocator,get the visits number from DB and increase 1.When user leave the Application,decrease onlineCount and update the visits number from DB.

I know there's a life cycle in ASP.NET and could easily implement this function in Global.asax,using Application_Start,Application_End,Session_start and Session_End event.

Is there any similar way to do that in Flex?

What's the best routine to implement online count and user visits?

Thanks in advance,Shuo