Mark Nottingham wrote:
On 14/10/2005, at 8:32 PM, James M Snell wrote:
1) Is it a closed or open set? If it's open (and I think 99% of
feeds are), what does "last" mean?
My answer would be: if "last" is used, it's a closed set; if "last"
is not used, it's an open set.
Can you walk me through a use case where this would be desirable?
E.g. what would the subscription URI be, would any of the entries be
updated, and how if so? In what scenario would having a closed set
feed be useful?
An archive for a blog that is no longer being updated? An archive of
entries pertaining to an event with a fixed endpoint? A discussion forum
that has been closed.
Separately, you say:
The "first" may not be relevant in the Feed history case but does
come into play when thinking about paged search results, sequences
of linked, non-incremental feeds, etc.
How? Can you give us a bit more flesh for the use case? Again, I'm
not saying it's bad, but I don't see how it's useful in a feed (as
opposed to a Web page).
Suppose that I perform a search on some feed searching service and get
back an entry from a feed in the middle of a set. I see the next and
previous links and realize that the entry I found is part of a larger
set. In order to get the full context, I want to navigate to the
beginning of the set and work my way down through the links to the end.
2) What's the relationship between these feed documents and the
feed document that people subscribe to?
I think the subscription feed needs to be pinned to one end of the
set (which is what FH does now). Otherwise, it becomes difficult
to figure out whether you have the complete set or not by polling.
I think this will be dependent on the context in which the link rels
are used. The "subscription" link rel you've suggested is a good
solution to this problem. Within any of the feeds in the set, the
"subscription" link rel would point to the feed that should be
subscribed to -- regardless of whether the subscription feed appears
at the start or end of the set.
What would the algorithm be for assuring that you have the complete
state of the feed, without necessitating traversal of the entire feed
every time?
Not sure. I suppose that it would be the same as it is with your
existing fh:prev element.
- James
