Re: FYI: Feed History extension

Hi Lucas,

Thanks for the reference. Having a complete archive has been
mentioned by a number of 
people (and was part of the original proposal I made to the Atom WG a
while back), but 
there was a lot of pushback from people who believe that the size of
the complete archive, 
in some cases, will be problematic. 

For example, if your feed has a history that goes back years, and you
have full content in 
the entries, there could be several (if not several tens or even
hundreds) of megabytes of 
content. If an automated (or just malicious) agent got a hold of the
URI for the archived 
feed (e.g., your aggregator subscribed to it) it could spell a lot of
trouble.

The proposal I made allows you to reconstruct the entire state of the
feed, by "walking" 
back through the archives. The downside of this is that potentially,
a number of requests 
need to be made, but with HTTP pipelining, etc., the overhead should
be negligible. 

All of that said, I'd be amenable to having some way of telling if an
archive is a full 
representation of the feed; I dropped it because so many people
(especially including 
implementors) thought it wasn't such a hot idea.

Also, note that fh:prev doesn't disallow the archive from being
complete; i.e., you could 
have one archive file that contains all entries, and just put an
fh:prev on your subscription 
feed that points to it, without any further fh:prev in the archive
(because there are no other 
entries).

WRT stateful -- the interesting case is when it's "false"; that tells
the consumer that they 
shouldn't try to keep a history (many aggregators do this by default
now, so this is a 
graceful way to introduce this explicitly hinted behaviour).

Cheers and thanks,

P.S. I'm not subscribed to e-mails from this list, so if you want to
make sure I see a reply, 
please CC me.

--- In [email protected], Lucas Gonze <lgonze@p...> wrote:
> A related issue came up in the Media RSS group.  Yahoo wanted an 
> 'archive' element to signify that a feed was either complete or
partial, 
> partial meaning that there were entries not included in the feed. 
The 
> purpose was to be able to retrieve (and publish) a complete copy of
the 
> feed.  The main difference between their proposal and yours was
that 
> there were two feed documents -- a current view of the feed with a 
> partial collection of entries and an archive view with a complete 
> collection.
> 
> If your fh:prev element allowed the archive to be complete, meaning
that 
> it includes both previous entries and entries in the current feed,
then 
> these proposals would be almost the same.
> 
> The fh:stateful element seems redundant.  My reading is that you
can 
> safely infer that a feed is stateful when you see an fn:prev
element -- 
> are there situations where that's not true?
> 
> Mark Nottingham wrote:
> 
> >I've put together the draft announced below as a way to allow
feeds'
> >history to be 
> >reconstructed; e.g., if Scripting News supported this (by adding
one
> >tag to the feed and 
> >archived feed headers), you could track Dave's writings back to the
> >very beginning, 
> >automatically.
> >
> >Note that it's submitted to the Atom WG, but it's equally
applicable
> >to RSS; there are RSS 
> >examples, and there shouldn't be any overhead or problem.
> >
> >I've modified my blog feed to demonstrate it:
> >  http://www.mnot.net/blog/index.rdf
> >
> >Comments and suggestions much appreciated,
> >
> >[[[
> >A New Internet-Draft is available from the on-line Internet-Drafts
> >directories.
> >
> >
> >        Title           : Feed History: Enabling Stateful
Syndication
> >        Author(s)       : M. Nottingham
> >        Filename        : draft-nottingham-atom
pub-feed-history-01.txt
> >        Pages           : 10
> >        Date            : 2005-7-1
> >        
> >This document specifies mechanisms that allow feed publishers to
give
> >   hints about the nature of the feed's statefulness, and a means
of
> >   retrieving "missed" entries from a stateful feed.
> >
> >A URL for this Internet-Draft is:
> >http://www.ietf.org/internet-drafts/draft-nottingh
> >am-atompub-feed-history-01.txt
> >
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> >
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> >Internet-Draft.
> ><ftp://ftp.ietf.org/internet-drafts/draft-nottingh
> >am-atompub-feed-history-01.txt>
> >]]]
> >--- End forwarded message ---
> >
> >
> >
> >
> > 
> >Yahoo! Groups Links
> >
> >
> >
> > 
> >
> >
> >.
> >
> >  
> >




 
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