ietf-nntp MODE STREAM (was: draft-ietf-nntpext-streaming-00.txt)

[Russ Allbery]

Clive D W Feather <clive at demon.net> writes:

> I'm not clear what's going on with MODE STREAM. I take it it's a command
> like MODE READER that possibly changes internal state.

Yes.  It's in essence a protocol negotiation that was developed before the
general extension mechanism was available.  The idea was that you send
MODE STREAM first to see if streaming is available and allowed.

> In which case, I suggest you copy the entirety of the MODE READER
> section and then edit it to describe the actual situation.

MODE STREAM can be pipelined (although you don't want to pipeline into
CHECK commands, obviously).

> Questions that immediately come to mind for me are:

> - Does using MODE STREAM make certain commands unavailable?

No.

> - Does LIST EXTENSIONS report STREAMING when MODE STREAM before this
>   command is used?

Yes.

> - Can I use CHECK without using MODE STREAM?

Yes, in the long term, I think.  I think MODE STREAM is more of a legacy
thing, although it's going to be an important one for a while.  Right now,
you have to send MODE STREAM before you send any of the streaming commands
and people put the check for whether you want to allow streaming in the
MODE STREAM command, but I don't see any need to continue that going
forward.  The command does need to be supported for backward compatibility
(since otherwise people won't stream at all), but I don't see any reason
for new servers not to start supporting CHECK and TAKETHIS for those
clients that they allow streaming before a MODE STREAM.

We may want to say something about all that.

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