[Standards-JIG] Re: pubsub tracking proto-JEP

Bob Wyman bob at wyman.us
Tue Feb 7 01:19:28 UTC 2006


Remko Troncon wrote:
> i don't think a person will subscribe from 2 clients
> at the same instant
	At PubSub.com, we regularly see users who have two, three or more
clients open at the same time. One will be at home, another would be at the
office and a third could be a daemon or fuselet process that does things
like forward results to their phones via SMS or Email. We've even had some
users implement systems that create subscriptions automatically in response
to detected events. (i.e. If you notice that some company has filed a 10-K
report with the SEC, then automatically create a weblog subscription to see
if any interesting comments appear... The same process has been used to
catch comments about earthquakes that exceed some magnitude.) All active
clients need to maintain a synchronized view of what subscriptions are
outstanding. Given a dynamic environment like this, only the server that
maintains that subscriptions can ever know what is subscribed to. Thus, I
can't see it is useful for a client to maintain persistent information about
anything other than which servers have subscriptions for it.
	An interesting protocol addition would be to publish to attached
clients information about changes to subscriptions that impact them but that
they didn't originate. (i.e. send out notifications of new subscriptions,
deletions, and modifications.)

	bob wyman






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