Re: [Jmap] Attachments and composing more complex MIME structures

[Neil Jenkins <[e-mail]>]

On Tue, 8 Aug 2017, at 07:23 PM, Josef 'Jeff' Sipek wrote:
> Some clients (most notably iOS Mail app) often produce multipart/mixed> emails with inline text and images.

Although not clear yet (this bit of the spec needs a lot more details),
the intention is that a JMAP server would convert this to an htmlBody in
the Message object that combined the text and images (with cids).
> However, I don't think the attachment API can be used to draft one of> these inline-mime-image mails since setMessages:

No, but you could produce an HTML part that's going to render the same
(and be more compatible).
> Did I miss something, or does this really mean that a client like this> must save drafts that are pre-composed RFC 5322 messages with all the
> inserted> images already embedded?

If the client absolutely MUST create a multipart/mixed email like this,
then yes. The intention with the Message object format is to hide the
complexities of MIME, and try to remove alternative ways of representing
the same things. This makes it easier for client authors, at the expense
of some more complexity for server developers.
> P.S. For what it is worth, the iOS mail app produces a totally
>      different> structure if any of the text has formatting.:
> 1.   text/plain with the whole text without any images
> 2.   multipart/related
> 2.1. text/html with the whole text with <img> tags using cids to
>      refer to>     the images
> 2.2. image/png with the first inserted image
> 2.3. image/png with the second inserted image

Doesn't sound like it would be difficult for it just to always generate
this even when no text formatting is applied then…
Neil.