[Twisted-web] 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