The (currently) definite way to achieve Push/Comet/Streaming in a GWT app? :)

[Stefan Sigvardsson]

Hi y'all!

Just a few quick questions. 

Background: 

We have a GWT app running on multiple touch-screen interfaces which need to stay up to date with each other. 

Currently we make scheduled callbacks to update the apps when they are idle, but some kind of Push technology would be preferable. 

We are not using app engine, instead we have our own tomcat 7 server which we deploy the application to. 

We are using RemoteService interfaces to do standard async callbacks to RemoteServiceServlet implementations. 

The touch-screens are all running the latest Firefox release (currently 9.0.1). 

We have held off dealing with Push, confident that GWT soon would include it natively, but now GWT seems to only focus on app engine from what I can tell. 

Questions:

1. What is your (currently) recommended way of dealing with Push in GWT? Is it still http://code.google.com/p/gwt-comet/ (or is it abandoned)?

2. Do you know if maybe GWT soon will include a simple Push technology for servers other than app engine?

3. If you have your own implementation, and it is stable and easy to run in a GWT app, would you mind sharing it?

Kind regards!

Stefan

[Andrea Boscolo]

There are a lot of libraries out there dealing with comet/push/reverse ajax technology. Some could be:

- http://code.google.com/p/gwt-comet/ (I don't see a valid update in almost an year)
- http://code.google.com/p/rocket-gwt/wiki/Comet (over 2 year of inactivity)
- http://code.google.com/p/atmosphere-gwt-comet/ (should be a gwt wrapper for atmosphere)
- http://code.google.com/p/gwt-comet-streamhub/ (I don't know if it could be work with tomcat)
- http://code.google.com/p/gwteventservice/ (updated, can be easily used with RPC, long polling/streaming options)

There are also websocket libraries (http://code.google.com/p/gwt-websocketrpc/wiki/ServerPushExample http://code.google.com/p/gwt-ws/), servlet 3.0 suspend/resume options, server-event communications and so on.
Probabily there are too many options to look into...

http://code.google.com/p/google-web-toolkit/issues/detail?id=267&colspec=ID%20Type%20Status%20Owner%20Milestone%20Summary%20Stars worth a read, even if it states a "PatchesWelcome" status and is ment for request factory.

GWT has always been server-agnostic, so you can still use whatever server tech you prefer. Of course by using servlets/app engine you can find some advantages.

Hope that helps.
Andrew.

[Stefan Sigvardsson]

GWTEventService looks promising, i'll look into that one. Thanks!

[Andrea Boscolo]

It has its own group: https://groups.google.com/forum/?hl=it#!forum/gwteventservice and forum http://gwteventservice.freeforums.org/
I've been using it in the last few weeks and looks (and works) good for my simple requests.

Andrew.