[NNTP] LIST EXTENSIONS and an NNTPv2 capability

[Clive D.W. Feather]

Ken Murchison said:
> I think where we diverge is that the NNTPv2 proposal follows the KISS 
> principal and only solves the existing problem(s); by putting a line in 
> the sand w.r.t. base functionality and existing extensions which we are 
> standardizing.  Your proposal wants to try to solve any problems with 
> extensions moving forward.

Yes, that's a key difference.

> 1)  Based on past history of IMAP/POP3/SMTP, few, if any, extensions 
> will have their functionality changed in any significant way.
> 
> 2)  If the functionality *is* changed in a drastic, non-backwards 
> compatible way, then a new extension should be advertised rather than 
> trying to wedge it into the existing extension.
> 
> 3) If the previous two assumptions turn out to be false, then we can 
> always address this issue at a later time.  The existing LIST EXTENSIONS 
> syntax already allows for extension labels to take arguments, which 
> could be used for versioning and/or enabled/disabled flags.

Okay. Furthermore, if we have reserved characters (as in the separate
proposal) then these can be used to introduce such a change as well.

>> My concerns, as explained in my previous messages, split into two areas:

>> (1) The ability to handle variations - version numbers - of extensions.
>> This *will* happen to lots of protocols, even if it hasn't happened yet.
> I agree that functionality *may* change for certain extensions, but my 
> guess is that the WGs responsible for the other protocols would just 
> create a new extension or separate extension label/capability.

I'm not convinced that's the right approach, but I appear to be pretty much
alone at present on this.

>> (2) NNTP's unique (as far as I know) concept of "extensions that aren't
>> available until you do something separate".
[...]
> I don't see this being an issue for clients.
[...]
> If we're interested in saving roundtrips, then we could always look at 
> Mark's proposal (which I haven't seen get to the list yet) of allowing 
> relevant responses to carry extension info.

I don't think this will work like this, but it's certainly worth thinking
through. Separate thread?

-- 
Clive D.W. Feather  | Work:  <clive at demon.net>   | Tel:    +44 20 8495 6138
Internet Expert     | Home:  <clive at davros.org>  | Fax:    +44 870 051 9937
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