feed.issued?

[Eric Scheid <eric.scheid@xxxxxxxxxxxxxxx>]

> 4.12  "atom:modified" Element [of <feed>]
> 
> The "atom:modified" element is a Date construct that indicates the time when
> the state of the feed was last modified, including any changes to entries
> therein. atom:feed elements MUST contain exactly one atom:modified element.

Say I poll the feed, and the <feed>'s <modified> element hasn't changed
since the last time I looked. I don't know by looking at that if there have
actually been any changes recently which have not yet been published. As
time goes by, and hours turn into days and days into weeks, I would have
decreasing confidence in that fact. For all I know, I could be polling the
wrong darn URL, with the real feed being somewhere else.

If however, the <feed> had an <issued> element, then I could tell just how
old that news is. If I see the feed has a very recent <issued> date, while
the feed <modified> date remained old, then this would be the equivalent of
saying "Here is the news: nothing's changed since last time".

Generally, I can see most feeds being issued when they get modified, and not
for any other reason (eg. a feed generated hourly by some automated system),
and so the <issued> date would be the same as the <modified> date.

One drawback of a feed issued hourly would be that the new feed wouldn't
304, even if the message is "there is no new news". For the (presumably)
rare case of a feed with a publishing schedule, I'd consider that OK - the
meta message of "as of 2 minutes ago, there is no new news" is qualitatively
better.

So, a suggestion for the spec:

> The "atom:issued" element is a Date construct that indicates the time when the
> feed was last issued, even if there have been no changes. atom:feed elements
> MAY contain an atom:issued element, but MUST NOT contain more than one. If
> atom:issued is not present, its content MUST be considered to be the same as
> that of atom:modified.

As you see, I'm thinking it would be an optional element. This is in
contrast to the entry.issued element, which is required. What do you think,
should the feed.issued element be required or optional?

e.