Sorry for taking so long to reply. I have been off on a 700km cycle trip
http://blogs.sun.com/roller/page/bblfish/20050807
I don't really want to spend to much time on the top-X discussion, as
I am
a lot more interested in the feed history itself, but here are some
thoughts
anyway...
On 29 Jul 2005, at 17:01, Eric Scheid wrote:
On 29/7/05 11:39 PM, "Henry Story" <[EMAIL PROTECTED]> wrote:
Below I think I have worked out how one can in fact have a top20
feed, and I
show how this can be combined without trouble with the
<history:next ...>
link...
On 29 Jul 2005, at 13:12, Eric Scheid wrote:
On 29/7/05 7:57 PM, "Henry Story" <[EMAIL PROTECTED]> wrote:
1- The top 20 list: here one wants to move to the previous top
20 list and
think of them as one thing. The link to the next feed is not
meant to be
additive. Each feed is to be seen as a whole. I have a little
trouble still
thinking of these as feeds, but ...
What happens if the publisher realises they have a typo and need
to emit an
update to an entry? Would the set of 20 entries (with one entry
updated) be
seen as a complete replacement set?
Well if it is a typo and this is considered to be an
insignificant change
then they can change the typo in the feed document and not need to
change any
updated time stamps.
Misspelling the name of the artist for the top 20 songs list is not
insignificant. Even worse fubars are possible too -- such as
attributing the
wrong artist/author to the #1 song/book (and even worse: leaving off a
co-author).
Yes, I see this now. This is a problem for my suggestion. The
atom:updated field
cannot be used to indicate the date at which an entry has a certain
position in a
chart for the reason you mention. We could then no longer update that
entry
for spelling mistakes or other more serious issues. One would have to
add
a about date or something, and then the things gets a little more
complicated
than I care to think about right now.
The way I see it, maybe a better way would be to have a sliding
window feed
where each entry points to another Atom Feed Document with it's
own URI, and
it is that second Feed Document which contains the individual
items (the top
20 list).
This is certainly closer to my intuitions too. A top 20 something
is *not* a
feed. Feed entries are not ordered, and are not meant to be
thought of as a
closed collection. At least this is my initial intuition. BUT....
Not all Atom Feed Documents are feeds, some are static collections of
entries. We keep tripping over this :-(
I can think of a solution like the following: Let us imagine a top
20 feed
where the resources being described by the entries are the
position in the
top list. So we have entries with ids such as
http://TopOfThePops.co.uk/top20/Number1
http://TopOfThePops.co.uk/top20/Number2
http://TopOfThePops.co.uk/top20/Number3 ...
will contain a new entry such as
<entry>
<title>Top of the pops entry number 1</title>
<link href="http://TopOfThePops.co.uk/top20/Number1/"/>
<id>http://TopOfThePops.co.uk/top20/Number1</id>
<updated>2005-07-05T18:30:00Z</updated>
<summary>Top of the pops winner for the week starting 5 July
2005</summary>
</entry>
The problem here is that this doesn't describe the referent, it only
describes the reference. I want to see top 20 feeds where each
entry links
to the referent in question. For example, the Amazon Top 10 Selling
Books
feed would link to the book specific page at Amazon, not to some
page saying
"the #3 selling book is at the other end of this link".
Oh, I don't really want to defend this position too much but there would
be a way around this criticism by simply having the link point to the
album
like this:
<entry>
<title>Top of the pops entry number 1</title>
<link href="http://www.amazon.fr/exec/obidos/ASIN/B00004ULZV"/>
<id>http://TopOfThePops.co.uk/top20/Number1</id>
<updated>2005-07-05T18:30:00Z</updated>
<summary>Top of the pops winner for the week starting 5 July
2005</summary>
</entry>
So here the id would be the same for each position from week to week,
but
the link it points to would change.
We would still need to solve the issue of the date at which it had that
position, though...
And so yes, a feed where the entry is a feed seems easier to work
with in this case.
The feed would be something like this I suppose:
<feed>
<title>top 20 French songs</title>
...
<entry>
<title>week of August 1 2005</title>
<id>...?...</id>
<updated>2005-08-01T18:30:00Z</updated>
<content src="http://TopOfThePops.fr/top20/2005_08_01/";
type="application/atom+xml">
</entry>
<entry>
<title>week of August 1 2005</title>
<id>...?...</id>
<!--There was an important update-->
<content src="http://TopOfThePops.fr/top20/2005_08_01/";
type="application/atom+xml">
<updated>2005-08-02T18:30:00Z</updated>
</entry>
<entry>
<title>week of August 8 2005</title>
<id>...?...</id>
<!--There was an important update-->
<content src="http://TopOfThePops.fr/top20/2005_08_08/";
type="application/atom+xml">
<updated>2005-08-08T18:30:00Z</updated>
</entry>
</feed>
But while you are at it then why not just create a special top-X
ontology and express
your information in RDF?
<feed>
<title>top 20 French songs</title>
...
<entry>
<title>week of August 1 2005</title>
<id>...?...</id>
<updated>2005-08-01T18:30:00Z</updated>
<content src="http://TopOfThePops.fr/top20/2005_08_01/";
type="application/rdf+xml">
</entry>
<entry>
<title>week of August 1 2005</title>
<id>...?...</id>
<!--There was an important update-->
<content src="http://TopOfThePops.fr/top20/2005_08_01/";
type="application/rdf+xml">
<updated>2005-08-02T18:30:00Z</updated>
</entry>
<entry>
<title>week of August 8 2005</title>
<id>...?...</id>
<!--There was an important update-->
<content src="http://TopOfThePops.fr/top20/2005_08_08/";
type="application/rdf+xml">
<updated>2005-08-08T18:30:00Z</updated>
</entry>
</feed>
Or if you want to make your life more difficult invent a special
purpose xml format for
your top-X. In either case you could really add all the bells and
whistles
for the particular domain of discourse of interest, such as
popularity, number of sales, etc, etc.
One can of course shoe-horn a top X into a feed document, but it
feels a little cramped...
Henry
