Dave Cridland schrieb:
On Thu Jul 16 10:57:51 2009, Jonathan Schleifer wrote:
I know that this is also an implementation issue, maybe more of an
implementation issue than a protocol issue. But having a protocol
that sends all initial presences at once would do two things:
1.) Force server developers to cache.
Which in turn would force many server developers to read the
specification, laugh hysterically, and ignore it. The base specification
clearly does not require caching of presence, and this is a substantial
amount of work, for very debatable gain. Speaking as a server
implementor, I doubt very much if I would implement such a proposal.
2.) You know when you got all presences and then definitely know if
somebody is online without waiting 10 minutes just in case you
didn't get the initial presence yet.
Responding to probes with an offline presence (as well as delay-stamping
probe responses) solves this.
Both these techniques would benefit from mentioning in the bis drafts
and/or a best-practise XEP.
Always responding to presence probes was already in RFC 3921. -bis
no longer mentions the option not to send a reply.
Not sending a reply MAY make sense, assuming that only 50% of your
contacts are online usually.
I think the best practise is something like "reply unless contact has
been offline for more than a week".
philipp
