Subject: Feed paging and atom:feed/atom:id

From: James M Snell <[email-masked]>
Date: Fri, 10 Mar 2006 09:44:21 -0800

Are linked feeds required to have unique atom:id values? Or, are they
required to have the same atom:id values?

That is, for instance:

  <!-- feed1.xml -->
  <feed>
    <id>tag:example.org,2005:feed1</id>
    <link rel="previous" href="feed2.xml" />
  </feed>

  <!-- feed2.xml -->
  <feed>
    <id>tag:example.org,2005:feed2</id>
    <link rel="next" href="feed1.xml" />
  </feed>

Or

  <!-- feed1.xml -->
  <feed>
    <id>tag:example.org,2005:feed1</id>
    <link rel="previous" href="feed2.xml" />
  </feed>

  <!-- feed2.xml -->
  <feed>
    <id>tag:example.org,2005:feed1</id>
    <link rel="next" href="feed1.xml" />
  </feed>

If the feeds have the same atom:id, I would submit that they form a
single logical feed.  Meaning that all of the feed documents in an
incremental feed (using Mark's Feed History terminology) SHOULD use the
same atom:id value.  This is the way I have implemented paging in our
APP implementation.  If the linked feeds have different atom:id values,
they should represent different logical feeds.

Thoughts?

- James

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From: Henry Story <[email-masked]>
Date: Fri, 10 Mar 2006 19:39:25 +0100

I think they should all have the same id.  But I don't have any good  
arguments in favor. It just seems to make sense that way.

Henry

---

From: David Powell <[email-masked]>
Date: Fri, 10 Mar 2006 19:17:20 +0000

> Thoughts?

The history spec frequently uses the phrase "the feed" in the
singular, this implies to me that the id's of the feeds must be the
same to the satisfy atom:id semantics.

-- 
Dave

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From: Antone Roundy <[email-masked]>
Date: Fri, 10 Mar 2006 12:36:14 -0700

> they should represent different logical feeds.

Agreed.  From 4.2.6:

    "Put another way, an atom:id element
    pertains to all instantiations of a particular Atom entry or feed;
    revisions retain the same content in their atom:id elements."

All the Atom Feed Documents representing one incremental feed (or  
parts of one incremental feed) are "instantiations of a particular  
Atom ... feed", are they not?  So they should have the same value in  
atom:id.  If they don't, then they can't be considered instantiations  
of the same Atom feed.

---

From: James M Snell <[email-masked]>
Date: Fri, 10 Mar 2006 11:56:25 -0800

Yep. Good.. I just wanted to make sure I wasn't making any baseless
assumptions with this.  sounds like I'm safe.

- James

Antone Roundy wrote:
> All the Atom Feed Documents representing one incremental feed (or parts
> of one incremental feed) are "instantiations of a particular Atom ...
> feed", are they not?  So they should have the same value in atom:id.  If
> they don't, then they can't be considered instantiations of the same
> Atom feed.
> 
>