On Wednesday, April 27, 2005, at 04:21 AM, Brett Lindsley wrote:
One reason for title only feeds is to address bandwidth limited devices. The
server I set up provides the same feed in two different formats - one title
only and the other with title/summary/etc. The end client can decide which
feed it wants to work with based on its capabilities;
This raises a few questions:
1) How does one indicate the existence of variants?
2) Can/should the variant feeds use the same atom:ids for variants of the same entries?
3) How does a client select a preferred variant?
4) How does an aggregator discover the "complete" and/or "authoritative" variant of an entry?
Here's a quick idea for how this might be done. Especially at this late stage, this would almost certainly go in an extension. But I bring it up now because of the issue raised by question #2 could mean that the extension MIGHT be contradicting the Atom spec if it said to use the same atom:id for multiple variants, depending on one's interpretation:
<feed>
<link rel="variants" ... /><!--this is a link to a file listing variants-->
<link rel="complete" ... /><!--this is a link to a variant which contains all of the elements found in any variant--it's conceivable that no such variant may exist in some cases--they might just be alternatives--or there could be more than one--thus this concept may not be useful-->
<link rel="authoritative" ... /><!--this is a link to the feed that the publisher considers to be the authoritative version from which the others are derived-->
...
</feed>
<variants xmlns="...">
<variant href="..."><!--the entries in this variant contains the following elements...-->
<elem>title</elem>
<elem>id</elem>
<elem>updated</elem>
<elem>[EMAIL PROTECTED]"alternate"]</elem>
</variant>
<variant href="..."><!--this could be "complete"-->
<elem>title</elem>
<elem>id</elem>
<elem>updated</elem>
<elem>[EMAIL PROTECTED]"alternate"]</elem>
<elem>[EMAIL PROTECTED]"html"]</elem>
</variant>
<variant href="..."><!--this also could be "complete"-->
<elem>title</elem>
<elem>id</elem>
<elem>updated</elem>
<elem>[EMAIL PROTECTED]"alternate"]</elem>
<elem>[EMAIL PROTECTED]"xhtml"]</elem>
</variant>
</variants>
