Re: more on the simplified feed format

[Seairth Jacobs <seairth@xxxxxxxxxxx>]

"Sam Ruby" wrote:

> Where exactly would you fetch this item from?  ID/GUIDs are not 
> guaranteed to be fetchable.

As I said, the content of the element would still be the entry 
document's URL.  In other words, a feed's entry element would look like:

<feed>
   <entry guid="uid:012345"/>http://example.org/entries/1</entry>
   <entry guid="uid:012346"/>http://example.org/entries/2</entry>
   <entry guid="uid:012347"/>http://example.org/entries/3</entry>
</feed>

Note that lack of the etag attribute is because I realized you could 
handle that bit by doing a conditional GET on the entry document itself 
(see my response to Randy).  This would also reduce the number of times 
the feed itself needs to be updated (kept synchronized with the entry 
documents).

However, the GUID still allows a couple things:

1) Allows you to detect if an entry URL has changed (as opposed to 
adding one entry and removing another entry).
2) Allows you to detect if the same entry exists in multiple feeds, 
regardless of the the value of the entry URL.  For instance, a cached 
copy of an entry could be kept at a different URL, but we would still 
know that the entries were the same (or at least closely related, since 
they may be different revisions).

> Even though it isn't an absolute minimum of bytes, an entry with a 
> link rel="alternate", an "id" and a "modified" element should be 
> sufficient.  Using relative URLs would often save more than the extra 
> bytes used by elements vs attributes.

Adding a <link> element would certainly be more extensible than just 
having a URL in the content of the element.  And if you do that, I agree 
that the guid attribute could be moved to an element.  So, the 
alternative format would be:

<entry>
   <link>http://example.org/entries/1</link>
   <id>uid:012345</id>
</entry>

I have intentionally left the <modified> element out for the same reason 
that I removed the etag attribute.  This way, even if the entry is 
modified (as long as the guid and link URL don't change), the feed does 
not need to change.

Seairth