Build Comet applications using Scala, Lift, and jQuery

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News: Build Comet applications using Scala, Lift, and jQuery

  1. Advanced Ajax libraries, such as jQuery, make it easy to write Comet applications on the client side, but getting them to scale on the server is still a challenge. That is where the Scala programming language and the Lift Web application framework can step in and deliver a scalable back end for your Comet application. In this tutorial, build a real-time Web auction using these technologies.
  2. Scala makes perfect sense for comet apps because of the Actor model, which makes it easy to process events. You can actually capture and process events for HTML elements like links, buttons etc., by simply passing messages to the appropriate actors. This is far better than the event dispatch model like in Wicket (which is similar to Swing’s). You write less code and components are loosely coupled. Does Lift have a proper template engine? The sample code in the article shows HTML in the classes…
  3. What are Comet applications ?[ Go to top ]

    What are "Comet" applications ?
  4. Re: What are Comet applications ?[ Go to top ]

    What are "Comet" applications ?
    A type of AJAX application where the server pushes data to the client. Chat in GMail is a good example. You can read about it here from the guy who coined the term: http://alex.dojotoolkit.org/2006/03/comet-low-latency-data-for-the-browser/
  5. Is it accessible[ Go to top ]

    I'm pretty keen on scala/lift.. but.. are the end applications accessible by default? It's a hallmark of a good design that it's leading edge in useful functionality, yet doesn't forget persons with disabilities, as well as mobile browsers, etc. There's zero chance I'd use it if it doesn't have support for accessible applications, effectively its not for general markets.
  6. One of Lift's committers, Charles Munat, insists that all his sites are accessible. Lift lets you build accessible sites.
  7. Thanks for clarifying that. How about migration strategies? I built a substantial app that uses a simple front end servlet and jsp pages, built around a context object embedded in the session. It has a lot of good details I wouldn't want to lose. Could I port my app gradually or is it all or nothing?
  8. Presentation separation.[ Go to top ]

    Well to be honest I haven't looked into Lift closely. But on a first impression it looks like logic and presentation are mixed liberally which put me off a bit. Is this really the case or should I just spend more time trying to grasp concepts of Lift?
  9. Lift's templating mechanism does not allow any business logic to exist in the views, yet the templating mechanism is powerful and flexible. So, it is very easy to enforce separation between presentation and business logic.
  10. Re: Presentation separation.[ Go to top ]

    first impression is just well... first impression. I would suggest you look at the Scala/Lift more closely before you "get off a bit" again. Short answer: There is clear separation present in the framework BUT for POC pursoses you may put small chunks in - at least for now.