☄ Cometd dev blog

We will be holding a developer meeting on irc on Wed, Feb 28.  It shouldn't last longer than an hour, but plan to stay for an hour.

Some topics that are up for discussion:

State of the Comet

• The latest progress on each of the server implementations, including the recent work on the perl server.  We may have a demo ready for the perl server also!
• Bayeux, including advices
  
• Flash socket connector
• Lightweight Bayeux JS library
• Unified test suite
• Python server and dojo bayeux client
  

I will schedule more of these, but at a later time.  Probably the same day and time.

Xantus
Project Lead

Grab your calendar and circle Jan 11th!

The Cometd project is having our first-ever developer get together at the Six Apart offices in San Francisco.
We'll even have some of our dojo friends there too!

Location:
548 4th St
San Francisco, CA 94107
Map

Time: 3pm ( tentative )
Demo at 4pm

Some of us will be having drinks later at the Hotel Utah Saloon.

It's been a good long while since we've blogged anything, but that doesn't mean that Cometd has been standing still.

Thanks to the tireless efforts of Greg Wilkins, the Bayeux protocol has been extended to support "advices", essentially server-sent "hints" that clients can use to avoid behaving badly. The Jetty implementation has advices implemented and the Twisted Python server is most of the way there. The laggards at this point are the clients who bare the brunt of the changes. They should be upgraded to handle advices soon.

Perhaps more excitingly, at this week's JavaPolis conference, Jonas Jacobi and John Fallows demonstrated a brand new Bayeux implementation based on Sun's Grizzly servlet container server. It was impressive to see them demo a real-time charting application that they developed using Dojo's charting infrastructure and their Bayeux server, all without any assistance from the Cometd team. We've been excited at how easy it is to implement Bayeux clients and servers to date, but out-of-the-woodwork implementations like these really help drive the point home that Bayeux's focus on simplicity is paying off.

It was an exciting OSCON for our little project. In addition to getting the first working demo running while sitting in the first night's keynote sessions, we had a small combined Dojo/Cometd BOF thanks to David's quick thinking.

In addition to general geekery, we also snuck in some time to discuss protocol semantics for the wire format that Cometd uses and a discussion of what to name the protocol.

In earlier discussions about what to call the project, Matt Trout had suggested "Bayeux", and while we eventually went with Cometd, we realize now that the protocol needs a separate moniker, so we're pressing Bayeux into service.

We hope to be publising a draft of the JSON protocol spec sometime in the next couple of weeks along with some demos (or at least a screencast of the demo we already have working). Until then, you can keep tabs on our progress in subversion and on the mailing lists.

-- Alex

Last week, the project formerly known as ShortBus was renamed Cometd.  Cometd is short for Comet Daemon.

What is Cometd?

Cometd is a scalable HTTP-based event routing bus that uses a push technology pattern known as Comet.  The term 'Comet' was coined by Alex Russell in his post 'Comet: Low Latency Data for the Browser'.   The term 'Daemon', as described by Answers.com is a program or process that sits idly in the background until it is invoked to perform its task.

There are efforts to create a Comet server in various languages.  Currently there is development underway on a Perl and Python comet server.  Others have expressed interest in writing one in Ruby on Rails, and Php.

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☄ David