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InfoQ Homepage Presentations Interactive Websites with Comet and DWR

Interactive Websites with Comet and DWR



In this session filmed during QCon London 2008, Joe Walker presents Comet, a long polling AJAX method used for updating the browser’s page, and DWR, a Java library for writing web sites using AJAX.


Joe Walker is lead developer of the DWR framework, and Director of Support and Development at Sitepen UK. He is a frequent speaker at industry events like InfoQ, JavaOne, FoWA and The Ajax Experience. He is an author of Ajax in Practice by Manning, and blogs at and also at

About the conference

QCon is a conference that is organized by the community, for the community.The result is a high quality conference experience where a tremendous amount of attention and investment has gone into having the best content on the most important topics presented by the leaders in our community. QCon is designed with the technical depth and enterprise focus of interest to technical team leads, architects, and project managers.

Recorded at:

Apr 08, 2009

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Community comments

  • Excellent!

    by Siva Prasanna Kumar,

    Your message is awaiting moderation. Thank you for participating in the discussion.

    Excellent talk, but what about the number of open connections on the servers? Isn't their a limitation on that? Hmmm long back I had written a article about Server Push using Blaze DS, in that article we had to explicitly specify the user-agent based settings as shown below:

    <user-agent match-on="MSIE" kickstart-bytes="2048" max-streaming-connections-per-session="3"/>
    <user-agent match-on="Firefox" kickstart-bytes="2048" max-streaming-connections-per-session="3"/>

    Do we need to do something similar in DWR also? My previous experience was with DWR 1.0, it was great but had some browser specific behaviors (had some issues with Mozilla, use to work great on IE). Never got a chance to look in to DWR 2.x, I think I will directly try DWR 3.0, when is it expected to release?


    Siva Prasanna.

  • I've another idea

    by Hazem Salem,

    Your message is awaiting moderation. Thank you for participating in the discussion.

    I used to implement comet using WCF (Dublex) over HTTP in real time applicaiton
    We face a lot of challenges in implmenting it but we succefully overcome them all and the idea is running perfectly now.
    we succfuly overcome the problem of this max-streaming-connections-per-session="3"
    Now no limits in using comet

    I'm preparing to post our idea soon


  • Comet on the rise?

    by Jurgen Huls,

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    I think general Comet use is on the rise again. Its the new Ajax, lots of people seem to be using it now. We're starting to implement Comet features in to our social networking site using StreamHub Comet server. Like DWR, we can use our existing Java skillset so it suited us. It will be interesting to see how Comet grows in the future.

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