On 11/22/2011 2:13 PM, Julien Genestoux wrote:
Jay,
I think the spec should say something like : "The publisher MUST inform the
hub about new content." without which, obviously the protocol won't work.
However the "how" should be left outside the protocol, or may be something
like "the hub MAY implement method X to get notifications".
I think one of the "design" principles of the protocol was that subscribers
should not care which hub a feed is using as their subscription should work
with *any* hub. On the other end, since the publisher designates a *specific
hub*, the hub and the publisher can agree on the method they want to use
without affecting anyone else.
In other words : there should be no coupling between subscribers and hubs,
no coupling between subscribers and publishers, but since there is coupling
(thru the discovery) between the hub and the publisher no matter what, we
should probably not spec it. Does it make sense?
Honestly, no - it doesn't make sense to me. The whole point of the
specification is to define expected behaviors universally. If a hub wants to
enable alternate discovery methods outside of the specification, there's
nothing preventing that, but I believe that having this defined is of
significant benefit to publishers. No matter what hub they use, they always
know that whatever software they implemented for notification will continue to
work. The publish method is ubiquitous at that point - there's no guesswork
for anyone involved. If made optional then every hub may institute different
policies which are /not/ universal.
By leaving update discovery methods up to each implementation, you're enabling
user lock-in because they won't want to go through the extra work required by
whatever their new hub might implement.
I always found it a failing that there was no ability for the publisher to
send a content blob along with their notification. In essence this turns the
publisher into a pseudo-hub, however they're only distributing to the central
hub, not directly to clients (and without adding hub discovery). This becomes
important in situations where publishing content may be behind a time-delay on
file updates. (e.g. a CDN, etc.) In the end, this just turns toward the
discussion of hub chaining (which has never been defined), not general purpose
publishing.
--
Jay Rossiter | Jack of All Trades
[email protected] <mailto:[email protected]> | Phone: 503.896.6187 | Fax:
503.235.2216
Website: dlvr.it <http://dlvr.it/> | RSS: blog.dlvr.it <http://blog.dlvr.it/>
| Support: support.dlvr.it <http://support.dlvr.it/>
