[Jmap] Message Tracking and JMAP extensibility (was Re: Submission is not hard)

["Chris Newman" <[e-mail]>]

On 21 Apr 2017, at 15:34, Adrien de Croy wrote:
> ------ Original Message ------
> From: "John Levine" <[e-mail]>
> To: "[e-mail]" <[e-mail]>
> Cc: "[e-mail]" <[e-mail]>
> Sent: 22/04/2017 3:16:36 AM
> Subject: Re: [Jmap] Submission is not hard
>>
>> Finally, if people want to try whizbang ways to show animations of
>> mail zipping through the aether, that sounds like a swell optional
>> add-on to try and implement and test and perhaps bring back later as
>> an extension, but it'd be nuts to try to invent it now.
>
> IME, if we don't design it now, it will never happen.  Surely it's 
> important enough to do the work up front?

I believe that client-convenient message tracking status is a desirable 
feature of a mail system. But the real world shows that tracking status 
and automated DSN/MDN handling is not sufficiently important for clients 
to have used existing facilities to provide that functionality; even 
though it's completely possible to do so. So no, I do not think this 
feature should be included in the base JMAP specification and believe 
the client developer community has spoken through their actions that it 
is not high priority. Furthermore, Message Tracking functionality is 
presently out of scope for the JMAP charter. The WG Chair can shut down 
any significant discussion on the topic to keep us on track to deliver 
the base JMAP specification.

What I'd consider appropriate to discuss on this list is if JMAP is 
extensible in such a way that we can add client-convenient tracking 
status to JMAP in a future extension. Extensibility is critical for a 
base specification to get right.

Here's an example client-convenient tracking model: have a 
server-mutable object attached to messages in the \Sent folder that can 
convey tracking status along the lines of RFC 3887 + DSN + MDN. I 
believe that's a completely workable model for message tracking that can 
be added in the future as a JMAP extension. Such an extension could go 
further and allow the JMAP view of the mailstore to convert DSN and MDN 
to status on the message in the \Sent folder (if such a message can be 
found) for clients that want the convenient delivery/tracking/MDN-status 
feature.

So the question that's in-scope for the working group is if there's 
anything in the present design of JMAP that would prevent an extension 
along those lines?

		- Chris