ietf-nntp LIST EXTENSION caching, latest wording

[Rob Siemborski]

On Mon, 13 Oct 2003, Clive D.W. Feather wrote:

> Personally, I still think it's better to have this stuff in there than
> nothing at all, but I agree it's important to send the right messages
> on security. So I hope we can all feel we're converging on good text.

Well, accurately describing exactly what must be done to get caching right
is going to be difficult in the base document.  By not mentioning it at
all (as with SMTP, IMAP, and POP) you can avoid the entire issue until an
extension requires specific behavior.

> In 5.3.2, one paragraph:
>
>    While some extensions are likely to be always available or never
>    available, others will "appear" and "disappear" depending on other
>    changes. An NNTP client may cache the results of this command, but
>    MUST NOT rely on any cached results - whether from earlier in this
>    session or from a previous session - remaining correct, MUST cope

Note that what you're saying here is that I have to issue LIST EXTENSIONS
right before I execute every command -- and even that isn't really good
enough, since the server can randomly change LIST EXTENSIONS after every
time you issue it (a bogus server, but this is what this requirement is
doing to the client)

*If* the consensus is that we must include text about caching
(which I think causes more problems than it solves), then something more like

  others will appear and dissapear depending on state changes within
the session.  An NNTP client MAY cache the results of this command, but
MUST NOT rely on any cached results - from previous sessions or across
session state changes that are documented to potentially invalidate
the LIST EXTENSIONS response - remaining correct.

would probably be better.

-Rob

-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
Rob Siemborski | Andrew Systems Group * Research Systems Programmer
PGP:0x5CE32FCC | Cyert Hall 207 * rjs3 at andrew.cmu.edu * 412.268.7456
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