Question

I was just wondering, How do comments appear instantly on Facebook? For example, when I’m on my profile and my friend comments something on my post, I can instantly see it. Is it AJAX? Or Queuing system? If I want to do the same thing, what do I do?

Thanks

Answer 1

I’m not exactly sure how facebook has implemented their system.
but it will either work with websockets, AJAX or a comet server.

If you want to have the same effect there are a lot of different techniques you could use,
but I would recommend looking into node.js and maybe even the now.js plugging, which allows for realtime updates via websockets. It even has support for older browsers, so if the browser does not support websockets, it will do a fall over to either a comet server implementation, AJAX or an iframe.

Basically websockets allow for better control over when data should be sent or received from and to the server since it constantly listening to the socket, so you only send data when required and same for receiving data as well, where with an AJAX approach you had to make a call every X seconds.

It’s extremely easy to setup on a linux environment, and there’s ample documentation to get you started.

It works with javascript and is build on the Google V8 engine, so if you’ve ever worked with OOP Javascript, you should be able to pick it up relatively easy.

LINKS:
http://nodejs.org/
http://nowjs.com/