"notification" pattern for web services

In several documents, I've seen references to providing web services
that follow the notification (or publish/subscribe) pattern, but I've
never seen any sample code. I can see a way to do it using socket
connections for the notification, but obviously there are going to be
many situations where this won't work.

Does anyone know where I can find code implementing a publish/subscribe
web service? The scenario I have in mind is: (1) the web service
advertises that it can provide information about a given set of topics;
(2) clients connect to the web service and subscribe to particular
topics; (3) other clients publish information about some topic by
sending that information to the web service; (4) the web service sends
the information to all the clients that subscribe to that topic. This
has to work regardless of whether the clients are behind a firewall, and
it would also be nice if there was some way for browser-based clients to
participate.

If building a publish/subscribe system using just web services is
impractical in the general case, I'd also be interested in other ideas
that would play well in a system that is primarily based on web
services.

Thanks in advance,

Steven Gollery
sgollery@cadrc.calpoly.edu

Received on Thursday, 24 January 2002 13:01:56 UTC