The other day, Jason Goecke wrote an awesome post about using Tropo with WebSockets.

I was inspired by Jason’s work to try and replicate it with a slightly different kind of technology. I also wanted to use Node.js.

I had come across the very cool faye Node.js library a while ago and wanted to try it out on a small project. This project seemed like the perfect fit.

Having now used faye for this project, I can tell you that I am amazed at how easy it is to use, and how powerful it is.

var faye = require('faye'), sys = require('sys'),
      http = require('http'), port = process.ARGV[2] || '8000';

var bayeux  = new faye.NodeAdapter({ mount: '/tropo' });

var server = http.createServer(function(request, response) {
  response.writeHead(200, {'Content-Type': 'text/plain'});
  response.write('Move along. Nothing to see here.');
  response.end();
});

bayeux.attach(server);
sys.puts('Server listening on port ' + port + "...");
server.listen(port);    

Examine the code for the Bayeux server used in this example above – in less than 15 lines of code I was able to create a server that can act as a real-time DTMF relay between a phone application running in the Tropo cloud, and multiple clients who can consume that input. How awesome is that!

(Note – all of the code used in this example is available on GitHub.)

To provide a bit more clarity and some contrast to the approach Jason used in his post, let’s talk about the Bayeux protocol and Comet servers.

Comet is really an overarching term used to describe push technologies in web browsers. Bayeux is one protocol for implementing a Comet server. From the spec:

Bayeux is a protocol for transporting asynchronous messages (primarily over HTTP), with low latency between a web server and a web client. The messages are routed via named channels and can be delivered:

• server to client
• client to server
• client to client (via the server)

Bayeux seeks to reduce the complexity of developing Comet web applications by allowing implementors to more easily interoperate, to solve common message distribution and routing problems, and to provide mechanisms for incremental improvements and extensions.

As Jason described in his post, the WebSocket spec is still in flux and will likely change going forward. How things shake out with the WebSockets spec and where Comet technoloiges fit into the mix is still the subject of some debate.

That aside, it is worth noting that you can use either technology with Tropo, and other real-time technologies as well.

With Tropo, there are a number of options available for building real-time applications across multiple channels.