Newbie question : client connection lost

Hi !
I am very new at Twisted. What i am trying to achieve is a simple web
service using basic HTTTP GET and POST requests. My big requirement is
being able to detect when the connection is closed client side. Bottom
line being : i want to know that each GET or POST result has been
successfully or not sent to the client. I could not managed to do that using WSGI. 
Is there way to try: catch sockets exception using Twisted or should i
go the async way and use notifyFinish() and friends ?

Thanks in advance !


Seb