[NNTP] 64-bit article counter extension strawman

[Russ Allbery]

Ken Murchison <ken at oceana.com> writes:

> I gave some more thought to this today and came up with the following:

> - Servers which support 64-bit (large) article counters advertise a
> capability such as 'LARGEGROUP' (or some better named capability).

> - If a group has exceeded the 32-bit article count, and the server
> supports the extension, then it uses a new 212 response code to
> GROUP/LISTGROUP which tells the client that the response may contain
> 64-bit numbers.

> - Similarly, a new 216 response code is used for LIST ACTIVE if any of
> the requested groups has exceeded the 32-bit article count.

> - Clients which don't support this extension will not understand the new
> response codes and *should* fail elegantly.

This is pretty nasty from a backward compatibility standpoint.  Old
clients that rely on LIST ACTIVE would potentially be unable to use the
server at all.  Plus, I hate to change the response code for a standard
command.

> As an alternative:

> - Servers which support 64-bit (large) article counters advertise a
> capability such as 'LARGEGROUP' (or some better named capability).

> - Servers always hide (411 response for [LIST]GROUP, ommission from LIST
> ACTIVE response) groups which have exceeded the 32-bit article count
> from clients until the client tells the server that it can support such
> groups.

> - A client tells the server that it supports large groups by using the
> new keyword 'LARGEGROUP' as an argument to the CAPABILITY command.

> - The server can then use the existing response codes for the
> [LIST]GROUP and LIST ACTIVE commands.

I like this a lot better; this was the sort of extension that I had in
mind.

One possible variation would be to add a new command other than GROUP for
accessing large-numbered groups and a new command other than LIST ACTIVE
for retrieving active file information, which would obviate the need for
client-side negotiation and storing additional server state to remember if
the client supports large-numbered groups.

-- 
Russ Allbery (rra at stanford.edu)             <http://www.eyrie.org/~eagle/>