[NNTP] Snapshot 6

[Ken Murchison]

Clive D.W. Feather wrote:

> Charles Lindsey said:
> 
>>I mean that if the OVER command is merely an "optional" command, and the
>>LIST OVERVIEW.FMT is also an "optional" command (or an "optional"
>>parameter to LIST, which comes to the same thing), then there is nothing
>>to prevent a server offerring either, neither, or both (and at least one
>>of those 4 possibilities is a nonsense).
>>
>>In the days when OVER was an extension, then those commands were never
>>"optional" (they were obligatory if you implemented the extension).
>>
>>I just want to be sure that the nonsense case(s) does not arise.
> 
> 
> This is not possible.
> 
> Under the old regime, nothing stopped a server creating an XOVER extension
> that did OVER but not LIST OVERVIEW.FMT. Or an XOVERFMT extension that did
> LIST OVERVIEW.FMT but not OVER. However, if it advertised the OVER
> extension in LIST EXTENSIONS, then it had to provide both commands.
> 
> Under the new regime, the same applies mutans mutandis.
> 
> Here's the actual situation:
> 
>   If server provides               then it
> 
>   * Neither                        MUST NOT advertise OVER capability
>                                    MUST NOT advertise OVERVIEW.FMT ... [1]
>   * Only LIST OVERVIEW.FMT         MUST NOT advertise OVER capability
>                                    MUST advertise OVERVIEW.FMT argument
>   * Only OVER                      MUST NOT advertise OVER capability
>                                    MUST NOT advertise OVERVIEW.FMT argument
>   * Both                           SHOULD [2] advertise OVER capability
>                                    MUST advertise OVERVIEW.FMT argument
> 
>   If server advertises             then it
> 
>   * OVERVIEW.FMT argument          MUST provide LIST OVERVIEW.FMT
> 
>   * OVER capability                MUST provide both commands
>                                    MUST advertise OVERVIEW.FMT argument.
> 
>   If server does not advertise     then it
> 
>   * OVERVIEW.FMT argument          MUST NOT provide LIST OVERVIEW.FMT
>                                    MUST NOT advertise OVER capability
> 
>   * OVER capability                MAY provide either command
>                                    SHOULD NOT provide both commands


Isn't providing LIST OVERVIEW.FMT or LIST HEADERS without OVER or HDR 
(respectively) nonsense?  I really don't see how the former are useful 
without the latter.

This goes back to my opposition to having OVERVIEW.FMT and HEADERS as 
arguments to the LIST capability.  By having these arguments, we open 
ourselves up to this kind of nonsense.  I believe that OVER and LIST 
OVERVIEW.FMT should be tied together via the OVER capability (you can't 
implement one without the other), and similarly for HDR.  In fact you 
almost state as much in pre-6 because the indicating capability for LIST 
OVERVIEW.FMT is OVER.

-- 
Kenneth Murchison     Oceana Matrix Ltd.
Software Engineer     21 Princeton Place
716-662-8973 x26      Orchard Park, NY 14127
--PGP Public Key--    http://www.oceana.com/~ken/ksm.pgp