From: Pete Resnick (presnick@qualcomm.com)
Date: Mon May 19 2003 - 11:29:44 CDT
On 5/16/03 at 1:59 PM -0400, Bruce Lilly wrote:
>1. While the 2822 issue affects a single production (viz. FWS) and in
> a very specific instance (a specific case of a continuation line),
> the discrepancies in the Lindsey draft are numerous and affect the
> ABNF for every header field (and presumably MIME-part header fields
> as well).
How about the bare CR and LF rule in 2.3? How about the table in 3.6?
There are some things that are required for interoperation that are
impossible (or at least really difficult) to put in the ABNF. And
these two certainly affect more than a single production.
>2. It is possible to comply with the 2822 restriction without violating
> MIME or other standards' restrictions, in every case. That is not the
> case with the must-have-non-whitespace-content-on-initial-field-line
> rule, as demonstrated by the example containing a long encoded-word
> (which must conform to the RFC 2047 line-length limit rule).
Nonsense. It is perfectly easy to comply with the
must-have-non-whitespace-content-on-initial-field-line rule in your
example:
From: (Comment to deal with broken parsers)
=?Extended_UNIX_Code_Packed_Format_for_Japanese*cel-gaulish?q?a?=
<a@b.com>
>3. A message containing the proscribed construct (essentially an "empty"
> continuation line) can be easily transformed into a compliant message
> simply and without affecting semantics (simply by eliding the line in
> question). That is not the case for the Lindsey draft restriction.
> (item #2 above affects message generators, this item (#3) affects
> gateways and other message-processing entities).
See previous answer. Compliant and doesn't affect the semantics.
>4. 2822 is the common text message format standards (track) document.
> It provides a single ABNF for From (and other) header fields. The
> Lindsey draft claims compatibility with 2822...
Uh, no it doesn't. It only claims that articles are a subset of 2822
messages. As far as I can tell, that's true: there are no articles
that are illegal under 2822.
>5. There exist such things as common UAs (these are nearly ubiquitous
> and include Netscape Communicator, Mozilla, MS Outlook/Outlook Express,
> Pine, etc.) and which are affected by such additional (i.e. not in
> the common message format) restrictions. This is a corollary of item #2;
> such UAs may find it impossible to cope with the restrictions when
> generating a message (which may be a followup).
By definition, if there are interoperability issues in one
environment that do not exist in the other, there are going to be
messages which cannot be reliably transported between the two. That
is the difficulty in being a gateway. I have yet to see an example
from you where a gateway can't at least do a reasonable job.
>6. Common UAs on the receiving end of messages must be able to parse and
> cope with full RFC [2]822 syntax in any event.
The must-have-non-whitespace-content-on-initial-field-line rule isn't
there for common UAs (assuming by that you mean combined UAs), so I
don't understand why you think this argument applies to what we're
discussing.
>7. There are common messaging protocols (e.g. IMAP) which may be affected
> by the differences.
An IMAP client receiving a messaging from usenet should have no
problem getting something it can understand. An IMAP client
*injecting* a message into usenet (or, more precisely, a gateway
doing so on its behalf) *is* going to have to watch itself. That's
what it is to be a gateway.
>8. 2822 has provision (via obs-FWS) which is documented (2822 section 4.2,
> including ABNF) requiring conforming parsers to be able to accept that
> which section 3.2.3 forbids generation of. The Lindsey draft has no
> such provision, nor documentation, for an acceptance requirement for
> conforming parsers which may encounter a field with (RFC 822-legal,
> 2822-legal, 2047-mandated) initial non-WS field body content appearing
> on a continuation line, such as may be generated by an 822/2822/MIME-
> compliant message generator.
This seems like a legitimate complaint, especially if we see messages
in the wild that do not conform to the draft. Documentation of those
things should appear.
>[Pete, I've addressed most of these issues in off-list email to you...]
Received.
pr
-- Pete Resnick <mailto:presnick@qualcomm.com> QUALCOMM Incorporated - Direct phone: (858)651-4478, Fax: (858)651-1102