pubsubhubbub

The pubsubhubbub is a simple, open, server-to-server web-hook-based pubsub (publish/subscribe) protocol as an extension to Atom and RSS. The servers speaking pubsubhubbub (PSHB) protocol can get near-instant notifications (via webhook callbacks) when a topic (feed URL) they’re interested in is updated.

In a nutshell, the protocol is something like this:
1. Feed URL declares its hub server(s) in its Atom/RSS xml file. It mentions <link rel=”hub” …>. The hub(s) can be run by the publisher of the feed itself, or it can also be a community hub that anybody can use.
2. A subscriber (i.e. the server who is interested in the feed) initially fetches the Atom URL as usual. If the Atom file declare its hub(s), the subscriber then can avoid the polling repeatitions. Instead, it can resiter with the feed’s hub(s) to get notified about the updates.
3. The subscriber now subscribes for ther target feed URL from the hub.
4. Whenever publisher updates the feed, it pings the hub(s) telling them about the update.
5. The hub now fetches the published updates and multicasts the new/changed update to all the registered subscribers for this feed!

You can see following video and/or slide show to get fair idea about PSHB protocol.

This project is hosted on Google code. Source code, wiki and some other doucments are also available there.

eAccess

Type: Web aggregation
Tech: PHP-MySQL on IIS Server
Role: Design, Development and Testing