Real-time chat with push notification

Question

Hi, I am working on a private messasing functionality for my site, is there a way to get push notifications from the server, that the user has received a new message?

the only technique I know is to constantly poll the server via ajax to see if there are new messages, and reload the messenger window if needed.

thanks for any feedback!

UPD: so far the following directions have been identified:

1) Comet
2) BOSH - Bidirectional-streams Over Synchronous HTTP
3) XMPP - this is what google talk is based on

Answer 1

There isn't any way for the server to push information to the client, but you could always use Comet. Yes, you'd be polling the server, but not constantly. You'd keep each connection open for about 30 seconds (that's the interval I've always seen used) and then open a new connection when needed.

EDIT: Adobe Flash allows persistent connections to the server, so you could use that. See this article for details.

Answer 2

Sounds like the Comet probably links to some useful stuff (Look into Google's GTalk):

http://alex.dojotoolkit.org/2006/02/what-else-is-burried-down-in-the-depths-of-googles-amazing-javascript/

Answer 3

You might want to look into XMPP and BOSH. Very comet like and ejabberd combined with nginx can maintain 1000's of connections on a very small box.

Take a look at one of my projects www.vooices.us to see what we have done with XMPP and BOSH.

http://www.ejabberd.im/

http://github.com/ssoper/jquery-bosh/tree/master JQueryBosh - to enable quick and easy access to XMPP over HTTP

It is relativly easy to set up and install.

Paul.