[NNTP] Extension snapshots 2

[Clive D.W. Feather]

Sorry: tuit supply shortage at work.

Russ Allbery said:
[quite a lot of sensible things]

>> what are those implications?
> Haven't we already covered this at great length in this discussion?

Yes, but how to put it in the document?

> Would it help if we just said that MODE READER MAY (but is not required
> to) reset the connection to the state that it was in immediately after the
> initial connection?

I can live with that. How does this look:

    If the server is mode-switching, it switches from its transit mode to
    its reader mode, indicating the fact by changing the capability list
    accordingly, and then MUST return a 200 or 201 response with the same
    meaning as for the initial greeting (as described in [REF]); note that
    the response need not be the same as the one presented during the
!   initial greeting. The client MUST NOT issue MODE READER more than once
!   in a session or after any security or privacy commands are issued.
!   When the MODE READER command is issued, the server MAY reset its state
!   to that immediately after the initial connection before switching mode.

[This paragraph only applies to mode-switching servers. For all other
servers MODE READER is a no-op or closes the connection, as appropriate.]

>> On the server side, I don't believe it is right to advertise a
>> capability when it is unsafe for the client to make use of it. If the
>> server state has changed, then either:
>> * MODE READER MUST NOT be advertised, or
>> * we must document how MODE READER affects the state.
> 
> So the choice is between fiddling with capabilities some more behind the
> back of the client or documenting that MODE READER may reset the state of
> the server.  The latter is looking more attractive to me; why not go with
> documenting the existing practice?

Okay.

> I guess I don't really care that much; all the solutions are ugly to me in
> one way or another, but that's because MODE READER is ugly so that
> shouldn't really be a surprise.

Indeed.

-- 
Clive D.W. Feather  | Work:  <clive at demon.net>   | Tel:    +44 20 8495 6138
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