ietf-nntp Re: [NNTP Draft] 8. The CAPABILITIES DISCOVERY Step
rra at stanford.edu
Sat Feb 26 23:04:01 PST 2000
These are responses to a complete reading of the current draft (I took
advantage of Andrew's recent posting of it to news.software.nntp to review
it). I'm commenting as I see things that seem unclear.
Andrew Gierth <andrew at erlenstar.demon.co.uk> writes:
> 8.1 LIST EXTENSIONS
> Each line listing an extension in the extension-listing
> begins with a single space. That space IS NOT optional, nor
> does it indicate general white space. This space guarantees
> that the line can never be misinterpreted as the end of the
> extension- listing, but is required even where there is no
> possibility of ambiguity.
I don't understand the purpose of this. What's the justification for not
using period-stuffing like every other multiline response uses? In
practice, the stuffing will rarely be necessary, as capabilities won't
begin with a period (in fact, that could simply be explicitly ruled out).
Requiring specific types of whitespace is a recipe for disaster. Humans
assume that where there is whitespace, arbitrary whitespace is allowed.
> A typical example reply to the LIST EXTENSIONS command might
> be a multiline reply of the form:
> [C] LIST EXTENSIONS
> [S] 202 Extensions supported:
> [S] OVER
> [S] PAT
> [S] LISTGROUP
> [S] .
Note that the single space doesn't appear to be present in the example.
> The client NNTP should configure itself for the basic NNTP
> functionality defined in this document, or issue commands that
> might change the state of the server, or issue the QUIT
> command (see section 10.1) if a particular extension is
> required for the client to properly operate.
The note about "commands that might change the state of the server" seems
a bit poorly specified and vague. At the least, I think it would be worth
saying that the client, upon taking any action that may make extensions
available, should confirm their presence by sending LIST EXTENSIONS again.
Russ Allbery (rra at stanford.edu) <URL:http://www.eyrie.org/~eagle/>
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