ietf-nntp Proposed new HDR text

[Charles Lindsey]

In <ylhemwjc0t.fsf at windlord.stanford.edu> Russ Allbery <rra at stanford.edu> writes:


>...  In particular, I have, for the
>time being, dodged the entire issue of metadata and specified a command
>that always and exclusively returns the actual values of the headers of
>the articles.

Fair enough, though I think we ought to consider that possibility in due
course.


>...  I've not put in any requirement that HDR be supported on any
>particular set of headers; we can debate that further if people feel
>that's necessary.

There are essentially two possibilities we are likely to encounter. The
implementation supports HDR on ALL headers, or it supports just those in
the Overview.

So let us have a parameter in the extension label, with values "ALL" and
"OVERVIEW". Make it optional, so if it is absent you can't assume
anything.

Now, if a client is really determined to find all occurrences of some
obscure header, it can call LIST EXTENSIONS. If it sees "HDR ALL", then it
can go ahead and use HDR. If it sees "HDR OVERVIEW" then it can have a
look at OVERVIEW.FMT to see if the header it wants is available. And if it
is not available or it sees just "HDR", then it can call HEAD on all the
articles in its range, which is expensive (but I did say that this client
was "really determined").


>      [S] 221 Header Follows
           ^^^ ^^^^^^^^^^^^^^
	   225 Headers Follow

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Charles H. Lindsey ---------At Home, doing my own thing------------------------
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