ietf-nntp Draft 17 pre-2

Russ Allbery rra at stanford.edu
Fri Feb 28 12:05:28 PST 2003


Charles Lindsey <chl at clw.cs.man.ac.uk> writes:

> Suppose some implementation decides to incldue the Foo:, Bar: and Baz:
> headers in the overviews (in addition to the 7 obligatory ones).

> Is there currently anything to stop it including those three headers (if
> and when they are present) in a different order for different articles?

No.

> Or, if the OVERVIEW.FMT said they occurred in a particular order, would
> the implementation be obliged to present them in that order?

In practice, no.

> And if, for some article, only the Bar: header appears, how can you tell
> from the overview alone which headers were being described as 'absent'?

You can't.

> And Russ said the OVERVIEW.FMT might keep changing its mind as to what
> headers were to be overviewed. But is that a realistic prospect, or just
> a theoretical possibility that could reasonably be ignored?

I'm unaware of any server that implements LIST OVERVIEW.FMT in a way such
that it's guaranteed to be consistent with the entire overview database.
That doesn't mean that such a server doesn't exist, however.

Another possible approach to this would be to state that LIST OVERVIEW.FMT
is optional and should only be implemented if the implementation can
guarantee that what it returns is consistent with the entire overview
database.  But even this doesn't address the question of what happens if
the headers that go into the overview database change during the course of
a single NNTP session.

-- 
Russ Allbery (rra at stanford.edu)             <http://www.eyrie.org/~eagle/>



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