[Standards] XEP-0080 interoperability

Stephen Pendleton pendleto at movsoftware.com
Mon Apr 12 20:52:44 UTC 2010


PEP is great - it works, easy to implement and widely supported on the
server side. 

Without a way to search meta information for pubsub nodes, or to have a
well-known name for common services though, pubsub itself is less useful
than it could be.

For example, in the microblogging XEP it suggests using PEP, but says: "A
person's microblog SHOULD be located at a personal eventing (PEP) node whose
name is "urn:xmpp:microblog:0" but MAY be located at a generic
publish-subscribe node that is not attached to a user's IM account. For
instance, if the Shakespearean character Romeo has a JabberID of
<romeo at montague.lit> then his microblog would be located at that JID with a
node of "urn:xmpp:microblog:0". Outside of native XMPP systems, this node
can be referred to as the following XMPP URI (see RFC 5122 [5]).
xmpp:romeo at montague.lit?;node=urn%3Axmpp%3Atmp%3Amicroblog".

It goes on to say you can use service discovery to discover this node, but I
am not sure that can really be accomplished. I wouldn't know what to look
for in the service discovery output in a machine readable manner.

Also, I am not sure how this works for pubsub - what does "located at that
JID" mean in the above text? The server that they jid belongs to? It is my
understanding that pubsub nodes are globally named so romeo at montague.lit and
Juliet at montague.lit cannot both publish to pubsub node
"urn:xmpp:microblog:0"

If pubsub nodes ARE NOT globally named in scope, and since microblogging has
"urn:xmpp:microblog:0" why don't we have geoloc use "urn:xmpp:geoloc:0"?

How would I subscribe to a node like this? This doesn't seem legal, because
the to jid should be the pubsub service, not the JID:

<iq type='set'
    from='francisco at denmark.lit/barracks'
    to='juliet at denmark.lit'
    id='sub1'>
  <pubsub xmlns='http://jabber.org/protocol/pubsub'>
    <subscribe
        node='urn:xmpp:geoloc:0'
        jid='francisco at denmark.lit'/>
  </pubsub>
</iq>

-----Original Message-----
From: standards-bounces at xmpp.org [mailto:standards-bounces at xmpp.org] On
Behalf Of Joe Hildebrand
Sent: Monday, April 12, 2010 1:51 PM
To: XMPP Standards
Subject: Re: [Standards] XEP-0080 interoperability

Down this path lies http://xmpp.org/extensions/xep-0119.html, which has been
fully obsoleted in favor of PEP.


On 4/12/10 11:32 AM, "Stephen Pendleton" <pendleto at movsoftware.com> wrote:

> That does look promising...the only issue is that you would need to
retrieve
> all the meta-data for every node in order to find the one you were
> interested in OR there would need to be a search mechanism to find it. The
> XEP suggests Jabber Search, but I don't see any examples of how to use it
to
> search pubsub collections. You may have millions of nodes on a server.
> 






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