On Tue, Dec 15, 2009 at 11:01 PM, Caldarale, Charles R <chuck.caldar...@unisys.com> wrote: >> From: André Warnier [mailto:a...@ice-sa.com] >> Subject: Re: [OT - question] Limit user sessions in tomcat >> >> It would seem that there ought to be some low-level response-direction >> socket flag that should be available, to tell whether the receiving end >> has gone, without actually having to send anything from a higher-level >> code module. But getting to that low-level socket data does not seem >> to be so easy in Java, is it ? > > It's not hard in Java (Socket.getRemoteSocketAddress() or > Socket.isConnected() should work), but there's nothing in the servlet spec > that allows a servlet thread to obtain for that information. Ideally, the > container (Tomcat) would asynchronously monitor the socket status and set > some flag in the Request object for the webapp code to examine at its > leisure. Might also be able to implement this with a new form of listener. > > I haven't looked at the Servlet 3 spec to see if anything is in there for > this rather common problem.
Hmm, last time I implemented a tcp/ip stack (which is more than 10 years ago) there were no possibility in the tcp protocol to detect a broken (not closed) connection except via so_timeout which should be large enough for a webapp to reply. As far as I know, socket.isConnected will never return false, once connected, even if you close the Socket on your side, isConnected will still return true. As for the OPs question (and i apologize if the answer was already given) the common approach to prevent f5-hitting users on long-running requests is to start a background thread which processes the request (or, more modern, use a Future and the Executor facilities) and return the current request back to the user with a waiting page, which refreshes itself in short periods checking whether the background task is yet finished and redirecting to the result page when done. regards Leon --------------------------------------------------------------------- To unsubscribe, e-mail: users-unsubscr...@tomcat.apache.org For additional commands, e-mail: users-h...@tomcat.apache.org
