[NNTP] Re: MODE READER

[Clive D.W. Feather]

Russ Allbery said:
>> There are three classes of commands: "transit", "reader", and "general".
>> Of the core commands apart from MODE READER:
>> * IHAVE is transit
>> * HEAD, STAT, LIST ACTIVE, LIST EXTENSIONS are general
>>   (that's what the present text implies; I think at least QUIT needs
>>    to be added to that list)
> QUIT is indeed also a general command.  (In practice, STAT probably is
> too, but we didn't put it into that category for some reason that I don't
> recall off-hand and which isn't important enough to revisit.)

Um, STAT *is* in that list. Did you mean something else?

>> * everything else is reader.
> Right.

>> There are *four* possible types of connection.
[...]
>> (4) Switching. Initially reader commands cannot be used; they get a 401
>> response. Once MODE READER has been issued, transit commands cannot be
>> used; they get a 502 response. MODE READER destroys all server state
>> apart from the switch and therefore LIST EXTENSIONS output can change in
>> this one case.
> 
>> Is this correct, in people's opinion?

But is it what we think happens in real life?

> This is correct according to what's specified in our standard.  It's worth
> noting that, as 401 is an innovation of this document, the last point
> isn't what happens right now in practice; instead, 502 is returned.

Yes, and we comment that as a historical point.

>> If so, then why don't I revamp the description to express it like that?
>> MODE READER can then be rewritten in these terms, which I expect will be
>> far less confusing. LIST EXTENSIONS can indicate which of the four cases
>> applies (I would make (1) the default, with the others being
>> READER_ONLY, TRANSIT_ONLY, and MODE_READER). We'll need to decide which
>> commands are "transit" and which are "reader", but that won't hold up
>> the rewrite.
> I'm not entirely sure that this will really be an improvement, but it may
> be.  In any case, let's hold off until we decide what extensions we're
> using to advertise the availability of IHAVE, POST, and reader commands,
> since that will have a lot of influence on the wording of the MODE READER
> description.

Um, no it won't.

My intention is to rewrite various parts of the document to talk about
"reader" and "transit" connections. Some commands will be tagged as reader
commands, which need not be supported on transit connections, and transit
commands, which need not be supported on reader connections. Then we talk
about using different ports, heuristics, both-transit-and-reader servers,
and, finally, MODE READER (if we don't kill it). I already have a fair
amount sketched out in my head.

How we advertise this becomes the least of our concerns. Really.

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