On 11/8/2009 5:26 PM, Peter Saint-Andre wrote:
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My apologies for the delayed reply.
On 10/2/09 12:46 AM, Brett Zamir wrote:
While attributes are being added to<item/>, would there also be some
way to add meta-data about the node to the event as well, e.g.,
pubsub#num_subscribers (the number of subscribers to the node) or
pubsub#title (human-readable node name)? I know it can be retrieved
separately, but this seems it could be useful to be able to get back
together...
I don't see the logic of this -- you want to include meta-data about the
node in an element that has information about a specific item?
I don't think it makes sense as a part of <item/> (nor as part of the
payload within <item/>) but a sibling of the <event/> in the <message/>
that delivers the item. It is, for example, wasteful to have to make a
separate query to know the number of subscribers for the node that just
delivered the item (our client would like to indicate this), but a
delivery of a news item would be an opportune time to be given an update
on the sending leaf node's variable meta-data (or possibly also
meta-data on the collection node containing the leaf node for which the
item was delivered)--maybe something like this:
<message>
<event><items>...</items></event>
<node type="leaf"
xmlns="http://jabber.org/protocol/pubsub#meta-data";><field
var="pubsub#num_subscribers"><value>121</value></field></node>
<node type="collection"
xmlns="http://jabber.org/protocol/pubsub#meta-data";><field
var="pubsub#num_subscribers"><value>345</value></field></node>
</message>
Some meta-data I think would make sense to deliver exclusively at the
time of a successful subscription (e.g., the value of
pubsub#creation_date delivered inside a <subscription/> element from
either an IQ response or as part of a subscription approval message
where approval was required), but other information like
#num_subscribers would be of potential use to update more frequently (it
is to us at least).
I suggested elsewhere in the thread that a (list-multi) option could be
added to subscription options which could provide choices of which
meta-data would be delivered in events, so not every subscriber/client
would need to get this information, but the delivery of meta-data could
have default values so a generic application would know which
information was typically shared to clients.
Brett
