MBOX-Line: From jkt at flaska.net  Wed Oct 16 14:24:57 2013
To: imap-protocol@u.washington.edu
From: =?iso-8859-1?Q?Jan_Kundr=E1t?= <jkt@flaska.net>
Date: Fri Jun  8 12:34:51 2018
Subject: [Imap-protocol] Accessing the Content-Transfer-Encoding of a
	=?iso-8859-1?Q?top-level_multipart?=
In-Reply-To: <CAKHUCzwE6K_ySgiTuHxXyX2V7z+etTngCQHRcQFzt6mNpSWA8Q@mail.gmail.com>
References: <18960e4a-19cb-4a82-b287-aee478965e77@flaska.net>
	<CAKHUCzwE6K_ySgiTuHxXyX2V7z+etTngCQHRcQFzt6mNpSWA8Q@mail.gmail.com>
Message-ID: <ee7bc79b-7903-4789-bde6-3d88aa9252ab@flaska.net>

On Wednesday, 16 October 2013 22:44:55 CEST, Dave Cridland wrote:
> Perhaps I'm misunderstanding, but isn't the CTE of any multipart/* 7bit 
by
> definition?

No, as per page 17 of RFC2045:

   Certain Content-Transfer-Encoding values may only be used on certain
   media types.  In particular, it is EXPRESSLY FORBIDDEN to use any
   encodings other than "7bit", "8bit", or "binary" with any composite
   media type, i.e. one that recursively includes other Content-Type
   fields.  Currently the only composite media types are "multipart" and
   "message".  All encodings that are desired for bodies of type
   multipart or message must be done at the innermost level, by encoding
   the actual body that needs to be encoded.

And indeed, I'm seeing multipart/mixed with CTE: 8bit; they are produced by 
mlmmj mailing list moderation.

The next paragraph is related to my fourth question: 

   It should also be noted that, by definition, if a composite entity
   has a transfer-encoding value such as "7bit", but one of the enclosed
   entities has a less restrictive value such as "8bit", then either the
   outer "7bit" labelling is in error, because 8bit data are included,
   or the inner "8bit" labelling placed an unnecessarily high demand on
   the transport system because the actual included data were actually
   7bit-safe.

It doesn't answer what one might expect when dealing with such errors -- I 
know that's a difficulr question, though.

Cheers,
Jan

-- 
Trojit?, a fast Qt IMAP e-mail client -- http://trojita.flaska.net/

