[Standards] vCard4: IQ vs. PEP

Dave Cridland dave at cridland.net
Wed Apr 6 19:13:33 UTC 2011

On Wed Apr  6 19:55:17 2011, Waqas Hussain wrote:
> Also, PEP in MUC is not a solved problem. I do like avatars in MUC.

I'd note that in Belgium, the consensus seemed to be to solve that  
problem rather than continue to work around it. Additionally, a  
recall the consensus as being to deprecate vcard4-for-avatars in  
favour of XEP-0084.

> All that said, I would really really love to have a generic  
> framework
> to do for PEP and pubsub and disco and everything what we currently  
> do
> for avatars via hash in presence. We added hashes in presence to  
> avoid
> iq:avatar, iq:disco and iq:version floods on login. When we start
> having large data in PEP/PubSub, PEP floods are going to become a
> serious problem.
> One obvious solution is a 'hashes' node in PEP. You subscribe to  
> that,
> and you get hash updates. A hash update is a set of hashes for  
> avatar,
> versions, custom namespace, etc. You send a manual request for what
> you want to actually get, and cache the result for the future. It
> would be nice to have this also requestable via IQ (possibly a  
> pubsub
> IQ).

Perhaps a subscription option?

We treat PEP's auto-subscribe from the bare jid, plus filtered  
notifications, as an auto-subscribe from each full-jid, incidentally,  
which makes this easier (if semantically wrong), but if these  
subscriptions could (by dint of an additional disco#info feature  
advertised via caps) indicate that a they only wishes to receive a  
hash of the last item on subscribe, that might work.

But I suspect it places us into a canonicalization trap, and in any  
case it will increase, not decrease, the number of stanzas.

Alternatives are to send a timestamp with initial presence - possibly  
managed by the server on a per contact basis to mitigate the privacy  

Dave Cridland - mailto:dave at cridland.net - xmpp:dwd at dave.cridland.net
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