Hi,
On Mar 5, 2009, at 5:51 PM, Waqas Hussain wrote:
The table is what I had in mind.
"highest common permissions" wasn't the best of phrases to use. What I
was thinking of was sending presence subscribe. This wouldn't be
appropriate with the current presence information available to servers
(i.e., someone removed me, and my server didn't realize, then my
server shouldn't resubscribe automatically).
Actually, that's the only action possible. If you add automatic re-
subscribe, I can send you a probe and trick you into subscribing to
me. This allows me to look at your probe's to know when you get
online. With an external component, this is a 10 minute hack.
Not good. So the only safe option is to lower the permission to the
highest level consistent with both sides. This way, with a none on my
side, you'll never be able to change me.
But suppose we add a
timestamp for every subscription (last change), then if a server sees
that it has newer information (local timestamp for subscription is
newer than remote timestamp received in probe), then the server can
send a subscribe automatically (this is in addition to the transaction
from the table you specified). This still doesn't solve everything
though.
Timestamps + distributed systems = fun.
I don't think you need this. You have to downgrade the subscription
level, so it does not matter what the sequence, just the current level.
Best regards,
--
Pedro Melo
Blog: http://www.simplicidade.org/notes/
XMPP ID: m...@simplicidade.org
Use XMPP!
