Can we make a asynchronous call from server to client in ext gwt

[samwells]

Hi
Is it possible to make a asynchronous call from server to client
which we call reverse ajax . Is it supported in ext gwt
Or is there any other way to do that

Thanks in advance

[gslender]

http://code.google.com/p/google-web-toolkit-incubator/wiki/ServerPushFAQ

[jpnet]

Here is a helpful wikipedia entry:
http://en.wikipedia.org/wiki/Comet_(programming) (http://en.wikipedia.org/wiki/Comet_%28programming%29)

-JP

[zaccret]

Hey, interesting question. Has anyone already implemented comet/server push in a GXT or GWT application ?

[sheesh-kebab]

I've done it - and would recommend using latest Jetty with Continuations and Spring MVC for this (e.g. spring MVC wrapping a raw GWT rpc - or you can also use json it doesn't particularly matter). There is some debate going on about hanging connections like Comet/Continuations vs polling. I can't say I'm onboard with either - I think it should be both and decision on which to use should be dynamically chosed by the application and ajusted at runtime, depending on the usage of the messaging/event sessions by the clients (i.e. the more clients are "interested" in the frequency of updates, the closer it would go to hanging connections and thus more timely updates). Keep in mind, most of the current web architecture/infrastructure, including load balancers/web servers are designed to handle small but large number of requests - rather than long/hanging reqs like those involved into Comet.

[zaccret]

I see that Jetty 7 also implements Servlet 3.0 spec, which permits suspendable requests (= server push "ouf-of-the-box" ?)

Why would you recommend Jetty/Continuations more than Tomcat/Comet ? Easier to use ?

[zaccret]

A new GWT framework has been released : GWTEventService.
The annoucement from http://gwteventservice.freeforums.org/first-version-of-gwteventservice-released-t2.html :

Hi,

2008-11-09: I am happy to announce that the first public version of
GWTEventService has been released!

The first public version is v0.9. All features for version v1.0 are
contained and I hope many developers are interested and will use and
test the framework in their applications, so that v1.0 can be reached
soon. GWTEventService is an event-based client-server communication
framework. The client side offers a high-level API with opportunities
to register listeners to the remote server like to a GUI component.
GWTEventService can be used to resolve "old-style" polling calls in
GWT applications with a clean and extensible architecture.

The release (developer-release) contains a small demo chat application
to demonstrate the event listening technique with GWT. I will try to
bring it online soon. A short manual / tutorial can be found in the
Wiki or in the developer-release of GWTEventService.

I would be glad, if some other people were also interested in support
or developing of GWTEventService.

Thanks in advance.

Sven StrohscheinIt is very interesting and looks well documented !!!! It provides both server side and client side API to implement server push. The official site is http://code.google.com/p/gwteventservice/
I'll try to test it as soon as possible.

[sdc]

Did someone test it ?

[EagleEye666666]

A new GWT framework has been released : GWTEventService.
The annoucement from http://gwteventservice.freeforums.org/first-version-of-gwteventservice-released-t2.html :
It is very interesting and looks well documented !!!! It provides both server side and client side API to implement server push. The official site is http://code.google.com/p/gwteventservice/
I'll try to test it as soon as possible.

Looks interesting, thanks for the info! :) (I do not need it, but i will keep that in mind)

kind regards