Re: [Resin-interest] Fwd: ajax push app - comet/gwt/continuations
On Sat, May 17, 2008 at 12:33:08PM -0700, jdk head wrote: Hi y'all, For an ajax push app... Has anyone had any luck with: A) integrating resin's comet support with GWT's server side - extends com.google.gwt.user.server.rpc.RemoteServiceServlet ? • given they both seem to be servlet wrappers, any way can they play nice together? Hi, I've taken a look at this, but I think the work to do it would be pretty involved from the GWT side. Also, you probably wouldn't use the RemoteServiceServlet on the server side. In the case of Comet, you either need to send a message to the client or invoke a procedure on the client. Thus what I'd like to see in GWT is the creation of a proxy for an interface that's implemented on the client. This whole problem is much better addressed by HMTP: http://www.caucho.com/resin/doc/hmtp.xtp But I digress... :-) The real underlying problem is that GWT has it's own RPC format for its RemoteServiceServlet and it needs to be reversed to send requests to the client and return responses from it. I think there's a real opportunity for GWT to create a generic way to handle this that would work with any Comet/server-push implementation. B) resin / continuations? C) resin comet / continuations? I'm not sure why you would want to use continuations with Resin, given its server-push architecture. Continuations have nothing to do with Comet per se, they are just Tomcat's implementation, except that what Tomcat calls continuations are not. Java doesn't support continuations and Tomcat's attempt at them is closer to SIMD programming than continuations. SIMD is hard to get right as a user. I used to work on MPI, so I know how much difficultly users have with the concept. Maybe comet would be all that's needed. My main concern is trying to not chew up all the threads. Yup. Resin's server-push does this just fine. Also, any advice on the best way to configure resin to handle a lot of sleeping concurrent requests? Seemingly continuations might help out with the threads part, but what about the tcp connections? Best handled with mod_caucho or resin direct? Check out the latest snapshot. It's got improvements for timeouts with server-push and HMTP. If you can avoid Apache, do it. Apache support is only for people who have existing installations with plugins not available in Resin. Using Resin's web server is much better integrated than Apache with Resin. Best, Emil Emil Ong Chief Evangelist Caucho Technology, Inc. Tel. (858) 456-0300 mailto:[EMAIL PROTECTED] http://blog.caucho.com/ Caucho: Reliable Open Source -- Resin: application server -- Quercus: PHP in Java -- Hessian Web Services ___ resin-interest mailing list resin-interest@caucho.com http://maillist.caucho.com/mailman/listinfo/resin-interest
[Resin-interest] Fwd: ajax push app - comet/gwt/continuations
Thanks, Emil, for the quick response When resin's comet suspends the thread, does it not count against the thread-max setting? If not, that's great. We're pretty deeply committed to GWT right now - lots of implementation already, so I need to figure out a good way to get GWT to work with resin comet. I can think of two possibilities to try: 1) make inital calls to GWT's RemoteServiceServlet, and pass its getThreadLocalRequest() and getThreadLocalResponse() into the comet servlet service() and resume(). Then hope the suspension and everything still works ok 2) make initial calls to a resin comet servlet, then dig into the GWT source and figure out what classes are doing the serialization of the RPC objects. Have the comet servlet use these directly. Could you see either approach working? and if so, which would you recommend? ___ resin-interest mailing list resin-interest@caucho.com http://maillist.caucho.com/mailman/listinfo/resin-interest
Re: [Resin-interest] Fwd: ajax push app - comet/gwt/continuations
On Sun, May 18, 2008 at 09:34:22PM +, jdk head wrote: Thanks, Emil, for the quick response When resin's comet suspends the thread, does it not count against the thread-max setting? If not, that's great. Yes, that's right. It may be better to think of it in this way, though: the Comet servlet uses the threads from the same thread pool as everything else. When it suspends, the threads go back into the pool. When it resumes, it takes a thread from the pool. No additional threads are being allocated for Comet either dynamically or statically. We're pretty deeply committed to GWT right now - lots of implementation already, so I need to figure out a good way to get GWT to work with resin comet. I can think of two possibilities to try: I think GWT is a great choice. I hope I didn't imply that I don't think it's suitable. It would be great if it had better Comet support, but AFAIK, it's not there yet. 1) make inital calls to GWT's RemoteServiceServlet, and pass its getThreadLocalRequest() and getThreadLocalResponse() into the comet servlet service() and resume(). Then hope the suspension and everything still works ok I'd have to check on this, but I don't think it would work. That is, I don't think you can pass a thread from a normal servlet to a Comet servlet. Also, I'm not sure what the semantics would be on the client even if you could. 2) make initial calls to a resin comet servlet, then dig into the GWT source and figure out what classes are doing the serialization of the RPC objects. Have the comet servlet use these directly. This is more on track, but the problem still remains that you have to decode an RPC request on the client. This actually isn't that hard, but it requires hacking the GWT compiler a bit. All you really need to do is create a stable name for methods on the JavaScript side, since GWT will mangle them in its standard and obscure modes. Then you can just send down JavaScript invocations of those methods. Could you see either approach working? and if so, which would you recommend? There has been some work on GWT and Comet. I've just glanced at these, so I can't give detailed comments. This one is a bit dated, but it might still work: http://www.jroller.com/masini/entry/a_comet_implementation_for_google This one uses Jetty, so I'm not sure if it would work with Resin. http://docs.codehaus.org/display/JETTY/GWT Best, Emil Emil Ong Chief Evangelist Caucho Technology, Inc. Tel. (858) 456-0300 mailto:[EMAIL PROTECTED] http://blog.caucho.com/ Caucho: Reliable Open Source -- Resin: application server -- Quercus: PHP in Java -- Hessian Web Services ___ resin-interest mailing list resin-interest@caucho.com http://maillist.caucho.com/mailman/listinfo/resin-interest
[Resin-interest] Fwd: ajax push app - comet/gwt/continuations
Hi y'all, For an ajax push app... Has anyone had any luck with: A) integrating resin's comet support with GWT's server side - extends *com.google.gwt.user.server.rpc.RemoteServiceServlet ? * - given they both seem to be servlet wrappers, any way can they play nice together? B) resin / continuations? C) resin comet / continuations? Maybe comet would be all that's needed. My main concern is trying to not chew up all the threads. Also, any advice on the best way to configure resin to handle a lot of sleeping concurrent requests? Seemingly continuations might help out with the threads part, but what about the tcp connections? Best handled with mod_caucho or resin direct? Thanks, and push on! ___ resin-interest mailing list resin-interest@caucho.com http://maillist.caucho.com/mailman/listinfo/resin-interest
