[Standards-JIG] JEP 60: Requesting Items for a Node

Peter Saint-Andre stpeter at jabber.org
Fri May 20 20:39:37 UTC 2005


On Sun, May 01, 2005 at 03:32:47PM -0700, Chris Mullins wrote:
> Section 8.1.10 defines the process by which an entity can request the
> persistant items for a given node ID. 
> 
> A few things here confuse me - hopefully someone will be kind enough to
> clarify. 
> 
> 
> > "When an entity requests items, the pubsub service SHOULD verify that
> the > requesting entity has a subscription to the pubsub node."
> 
> Does this means that Owners and Publishers can't request the items for a
> node unless they also are subscribers? 

I think it would be reasonable for a pubsub service to consider owners 
and publishers to have "super-user" status and to allow JIDs with those 
affiliations to retrieve items. 

If Peter and Ralph don't have any objections, I will add a note about 
that.

> > If a subscription identifier is associated with a specific
> subscription,
> > the entity MUST append the 'subid' attribute to the items element when
> 
> > making the request (if it does not, the service SHOULD return a <not-
> > acceptable/> error).
> 
> This sentence doesn't make sense to me. By definition, a subscription
> identifier is associated with a specific subscription! When is this not
> true? 

By definition a SubID is associated with a subscription (what else would
a SubID be associated with?), but not all subscriptions have SubIDs.

> The whole 'subid' as an optional tag is confusing throughout the pubsub
> JEP. When a subscription happens, if it's not in the "multiple" case,
> there's no requirement for the 'subid'. This means that subid can't be a
> purely required field, as it's not always present. This is additional
> confusion and special casing for both clients and servers - and because
> it's special casing, it's going to have major compatiability issues
> between client implementations. 
> 
> Why not just make it required in all cases? 

Hmm. Currently, the SubID is used to differentiate between multiple
subscriptions from the same JID -- or, more precisely, it is used by 
the pubsub service on any subscription to a node that allows multiple
subscriptions to the same node by the same JID (so if the node allows
multiple subscriptions, then the service MUST add the 'subid' attribute
if one is not provided by the subscriber). If we specify that the SubID
is required in all cases, then services will be generating SubIDs when
they're not really necessary or used. I don't know if that is a major
hardship or not -- perhaps some implementors could voice their opinions.

Furthermore, no guidelines are specified for the generation of SubIDs.
At the least, I think the JEP needs to say that a SubID MUST be unique
per node+jid combination.

/psa




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