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Re: Updated news-nntp-uri I-D

From: Frank Ellermann <nobody@xyzzy.claranet.de>
Date: Sun, 24 Feb 2008 03:27:05 +0100
To: uri@w3.org
Message-ID: <fpqkiq$qmc$1@ger.gmane.org>

Clive D.W. Feather wrote on the NNTP list 2007-11-28:

>>> RFC 3977 is much more generous in what it allows:
>>>     message-id = "<" 1*248A-NOTGT ">"
>>>     A-NOTGT    = %x21-3D / %x3F-7E  ; exclude ">"
 
>> OK, we have essentially two possibilities:
>> 1. restrict it to the USEFORE msgid syntax
>> 2. allow the wider RFC 3977 syntax
 
>> The point I was making was that if we went for #1,
>> as Franks draft proposes, then we should use the
>> syntax given in USEFOR normatively, rather than
>> inventing yet-another-version-of-it.
 
> Agreed. But I don't accept #1.

It is required for backwards compatibility among other 
reasons.  Almost all RFCs specifying something in the
direction of a Message-ID use the pattern <unique@domain>
with a syntax based on the <local@domain> pattern in
email addresses.

Notably that is also what RFC 822, RFC 1036, RFC 1738,
s-o-1036, RFC 2822, RFC.usefor-usefor, and 2822upd do,
known problems in 822 and 2822 not withstanding.

RFC 977 is based on RFC 850 (obsoleted by 1036), and
RFC 850 is based on RFC 822, so that is arguably also
about a Message-ID with "@". 

RFC 733, the predecessor of RFC 822, still used the
clause "at" instead of "@", separated by LWSP from the 
LHS (local / unique) and the RHS (domain).  This is
now ancient history, and a proposal to add syntax in
2822upd for occasionally parsing 733 messages did not
fly on the rfc822 list.

Obviously RFC 2822 ignored what works for NNTP, and
RFC 3977 ignored what works for s-o-1036 and RFC 1738.

The IETF USEFOR WG missed that there is a problem with
the most fundamental aspect of Netnews, the Message-ID,
for some years.  There were two separate drafts about
the Message-ID in 1998, both of course using "@".

IIRC in 2004 the USEFOR WG figured out that NO-WS-CTL,
permitted in (2)822, won't fly with NNTP, and fixed it
in the new "usefor-usefor" series of drafts leading to
what is now RFC.usefor-usefor.  It defines the maximal
proper subset of RFC 2822 still working with NNTP.

The Gilman drafts about the news and nntp URI schemes
in 1998 tried to unify both schemes, allowing to point
to specific servers and groups also in news URLs.  For
this purpose it's essential to distinguish Message-IDs,
NNTP article numbers, and newsgroup names syntactically.

To some degree it worked, the augmented news syntax was
widely adopted, today the nntp syntax is rarely used.

It is still needed if folks really want an NNTP article
number, and purists might still prefer the RFC 1738 nntp
syntax for talking about a group on a specific server -
the RFC 1738 news syntax did not offer this, this is a
"new" (1998) feature of the Gilman drafts.

With article numbers out of the way (by restricting them
to nntp URLs as in RFC 1738) the news scheme still needs
a clear syntactical distinction between a Message-ID and
a newsgroup name.

This clear distinction is the "@", as found in RFC 1738,
the Gilman drafts, and in STD 66 <gen-delims>.  In other
words RFC 3986 has precisely what's needed as a general
delimiter.

That RFC 3977 doesn't need the "@" for its own purposes
is understood.  But RFC 850 was published in 1983, for
about 25 years Message-IDs have an "@", and RFC 1738 was
published 1994, for about 14 years news URLs have an "@"
when talking about a Message-ID.

The news-nntp-URI draft tries to document common practice
based on RFC 1738 (as amended by the Gilman drafts) with 
the minimal updates needed for STD 66 for these schemes.

It expressly does not try to introduce some new features
theoretically permitted in RFC 3977, when that could harm
interoperability or backwards compatibility.  When users
see a news URL they should be confident that it works for
them no matter which UA or server they use.  

Likewise users creating some news URL should be confident
that this works for any UA and server, provided that the
article or newsgroup (still) exists on this server.  It
makes no sense to allow hypothetical Message-IDs without
"@" in news URLs when that is not allowed in any 2822upd
or RFC.usefor-usefor message.

 Frank
Received on Sunday, 24 February 2008 02:25:52 UTC

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