[standards-jig] [jepnews] JEP-0021: Jabber Event Notification Service

DJ Adams dj.adams at pobox.com
Wed Mar 6 14:22:26 UTC 2002


On Tue, Mar 05, 2002 at 12:51:53PM -0600, Peter Saint-Andre wrote:
> Question about http://www.pipetree.com/testwiki/JabberPubsubSpec --
> DJ, how would you define "publisher"?

A publisher is any entity (for example a JSM user or a component) 
that wants to publish, or send out, data for consumption (by consumers,
who have subscribed to that data by namespace).

All a publisher has to do is to push (IQ-set) data to a pubsub 
component, and the pubsub component will handle it from there, 
delivering that data to those consumers who have subscribed to 
data in that namespace (and optionally specifically from that
publisher). The publisher only has to send the data to one entity
destination, and the pubsub component will deal with the diffusion. 
The publisher also doesn't have to manage the subscriptions - that's
done by the pubsub component. 

As an example, consider the replacement of the typical headline
message component that retrieves RSS data, and pushes it out according
to who asked for it. Instead of that component having to send each
item out N times, it sends it once, to the pubsub component, like this[1]:

SEND: <iq type='set' to='pubsub.localhost'
           from='headline.localhost' id='rss32'>
        <query xmlns='jabber:iq:pubsub'>
          <publish ns='jabber:x:oob'>
            <query xmlns='jabber:x:oob'>
              <url>http://www.pipetree.com/jabber/</url>
              <desc>Some gunk</desc>
            </query>
          </publish>
        </query>
      </iq>


where the pubsub component would then diffuse it out, sending 
something like this:

SEND: <iq type='set' to='subscriber at localhost'
           from='pubsub.localhost' id='push22'>
        <query xmlns='jabber:iq:pubsub'>
          <publish ns='jabber:x:oob' from='headline.localhost'>
            <query xmlns='jabber:x:oob'>
              <url>http://www.pipetree.com/jabber/</url>
              <desc>Some gunk</desc>
            </query>
          </publish>
        </query>
      </iq>

to each subscriber.

dj



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