Re: [Jmap] the large email (attachment) problem

John R Levine <johnl@taugh.com> Sun, 01 August 2021 17:43 UTC

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Date: 1 Aug 2021 13:43:30 -0400
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From: "John R Levine" <johnl@taugh.com>
To: "Jamey Sharp" <jamey@minilop.net>
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Subject: Re: [Jmap] the large email (attachment) problem
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>> Take a look at message/external-body in RFC 2017, 2046 and 2912.  It already has size,
>> URL, expiration, and content-features parameters.

> I assume the "normal" way to use this in an HTML email would be to assign a 
> Content-ID to the multipart/alternative containing the external-body, if 
> there is one, or to the external-body part itself, and then reference it 
> using "cid:" links, right? But that doesn't work if recipients don't 
> understand message/external-body.

External-body parts are just like any other MIME part, and can go 
anywhere.  It is my strong impression that the vast majortity of giant 
MIME parts are attached videos or other opaque formats so they appear as 
attachments.  I don't see any reaspn a Content-ID wouldn't work but it 
rarely would be needed.

I agree there is a bootstrap problem.  Some mail programs implemented it 
back in the 1990s when people still dialed in to download their mail, then 
it went away when we all got permanently online, now we need it again as 
the size of bloatware has pulled away from what mail systems do.

Regards,
John Levine, johnl@taugh.com, Taughannock Networks, Trumansburg NY
Please consider the environment before reading this e-mail. https://jl.ly