Re: [Extra] Is this a plausible IMAP extension ?

Arnt Gulbrandsen <arnt@gulbrandsen.priv.no> Thu, 28 February 2019 18:08 UTC

Return-Path: <arnt@gulbrandsen.priv.no>
X-Original-To: extra@ietfa.amsl.com
Delivered-To: extra@ietfa.amsl.com
Received: from localhost (localhost [127.0.0.1]) by ietfa.amsl.com (Postfix) with ESMTP id 6F689130F04 for <extra@ietfa.amsl.com>; Thu, 28 Feb 2019 10:08:10 -0800 (PST)
X-Virus-Scanned: amavisd-new at amsl.com
X-Spam-Flag: NO
X-Spam-Score: -2
X-Spam-Level:
X-Spam-Status: No, score=-2 tagged_above=-999 required=5 tests=[BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1] autolearn=ham autolearn_force=no
Authentication-Results: ietfa.amsl.com (amavisd-new); dkim=pass (1024-bit key) header.d=gulbrandsen.priv.no
Received: from mail.ietf.org ([4.31.198.44]) by localhost (ietfa.amsl.com [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id N_Zhw37P17fY for <extra@ietfa.amsl.com>; Thu, 28 Feb 2019 10:08:08 -0800 (PST)
Received: from stabil.gulbrandsen.priv.no (stabil.gulbrandsen.priv.no [IPv6:2a01:4f8:191:91a8::3]) (using TLSv1.2 with cipher ADH-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ietfa.amsl.com (Postfix) with ESMTPS id 6FD0B12F1AB for <extra@ietf.org>; Thu, 28 Feb 2019 10:08:08 -0800 (PST)
Received: from stabil.gulbrandsen.priv.no (stabil.gulbrandsen.priv.no [IPv6:2a01:4f8:191:91a8::3]) by stabil.gulbrandsen.priv.no (Postfix) with ESMTP id 51924C05E3; Thu, 28 Feb 2019 18:09:57 +0000 (GMT)
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=gulbrandsen.priv.no; s=mail; t=1551377397; bh=Chtygh/p2KVktBtN6LrcbU+Cy2u8V58vg0AEsL+E5gY=; h=From:To:Subject:Date:In-Reply-To:References:From; b=hS8RPKW1jhy5AW8+J+CdpOslfIPsYiH+v3c3U+CSfK/YWqc3UJ8wWCbsSviH3db14 96zZRfwUFrZzKMlwJPRf4eqk5+Zob58+CJNPOKM55bR3pwYUf+QdVW+8y7iv7yOQlD BILiL2gokTiSvnLcWl3GvqPu2z1BfC8uMY7o1Ykc=
Received: from arnt@gulbrandsen.priv.no by stabil.gulbrandsen.priv.no (Archiveopteryx 3.2.0) with esmtpsa id 1551377396-2663-2661/9/152; Thu, 28 Feb 2019 18:09:56 +0000
From: Arnt Gulbrandsen <arnt@gulbrandsen.priv.no>
To: extra@ietf.org
Date: Thu, 28 Feb 2019 19:08:04 +0100
Mime-Version: 1.0
Message-Id: <01fd8d9e-fe47-453a-b4e0-f0a9d68ce43b@gulbrandsen.priv.no>
In-Reply-To: <20190228161213.D1442200F6FF92@ary.local>
References: <alpine.OSX.2.21.1902262150050.14048@ary.local> <af25a165-ff24-41d4-810e-b00adf2092d5@beta.fastmail.com> <01R3P86JVOOM00004L@mauve.mrochek.com> <a05121fb-a105-458a-bd69-9d6c289860b2@www.fastmail.com> <20190228015702.5B252200F6CDEE@ary.local> <8ce7f4bf-805d-4fbe-8854-5381a4346b2a@gulbrandsen.priv.no> <20190228161213.D1442200F6FF92@ary.local>
User-Agent: Trojita/0.7; Qt/5.7.1; xcb; Linux; Devuan GNU/Linux 2.0 (ascii)
Content-Type: text/plain; charset=utf-8; format=flowed
Archived-At: <https://mailarchive.ietf.org/arch/msg/extra/pI9-riJiqNLr4q-hLoyufzFpoRo>
Subject: Re: [Extra] Is this a plausible IMAP extension ?
X-BeenThere: extra@ietf.org
X-Mailman-Version: 2.1.29
Precedence: list
List-Id: Email mailstore and eXtensions To Revise or Amend <extra.ietf.org>
List-Unsubscribe: <https://www.ietf.org/mailman/options/extra>, <mailto:extra-request@ietf.org?subject=unsubscribe>
List-Archive: <https://mailarchive.ietf.org/arch/browse/extra/>
List-Post: <mailto:extra@ietf.org>
List-Help: <mailto:extra-request@ietf.org?subject=help>
List-Subscribe: <https://www.ietf.org/mailman/listinfo/extra>, <mailto:extra-request@ietf.org?subject=subscribe>
X-List-Received-Date: Thu, 28 Feb 2019 18:08:11 -0000

On Thursday 28 February 2019 17:12:13 CET, John Levine wrote:
> Urrgh.  Most of the mail that's likely to have a logo is 
> multipart/alternative
> and I'm not interested in wrapping contents in yet more MIME 
> layers, which would
> among other things break any existing DKIM signatures.

You don't need that. Look at 3676. It doesn't wrap, it marks. In this case, 
either mark the top-level multipart with the content-id of the logo

  content-type: multipart/mixed; boundary=foo; logo=bar

(the logo will mostly have a content-id because the html refers to it) or 
mark the bodypart with the logo

  content-type: image/jpeg; content-id=bar; logo

or mark the logo's disposition

  content-disposition: attachment; logo

It's not obvious to me which way is the best. Is being a logo part of the 
type or rather part of the disposition? I don't even want o discuss that.

All are immutable though, since they're part of the message, and the info 
is returned as part of the FETCH BODYSTRUCTURE command most/all clients 
use. Very easy to implement in typical clients, and zero work for the 
server.

Arnt