[EPIC] JMAP protocol support

[okias]

I'd like to create this issue for tracking of JMAP protocol support [1] progress/interest. I guess at some point JMAP protocol will be implemented by K9 Mail.

This time, JMAP is already implemented in few Mail servers, so wide adoption will probably follow soon.

Update: there is guide for client authors: https://jmap.io/client.html

[1] http://jmap.io/

Subtasks

• JMAP: add support for sending messages #4564
• JMAP: respect maximum download size #4565
• JMAP: add server settings screen #4566
• JMAP: support remote search #4567
• JMAP: don't show "load up to X more" when all messages have already been downloaded #4568
• JMAP: tweak Proguard rules for jmap-client library #4569
• JMAP: add support for messages in multiple folders #4570
• JMAP: respect maximum message age on sync #4572
• JMAP: allow setting up JMAP accounts #4573

[ghost]

Recently this was published:

https://fastmail.blog/2018/12/27/jmap-is-on-the-home-straight/
https://news.ycombinator.com/item?id=18766709

I think JMAP is an eventual evolution. It has a lot to offer particularly on mobile devices which IMAP was not designed for. It would be a suitable investment in time for K-9 to be the first JMAP client. I do see this being eventually baked into Android however as a complete replacement for IMAP.

[marclaporte]

This request (which I strongly support) is now listed at: https://jmap.io/software.html

[iNPUTmice]

Just as a quick FYI there is a Java / Android library available here: https://github.com/iNPUTmice/jmap

The jmap-mua part of the library makes a lot of assumptions about the mail client, its work flow and how it stores it's data and might not be a good fit for k9. However the lower level jmap-client module would still take a lot of work of the shoulders of anyone wanting to implement JMAP in k9.

[cketti]

I'm happy to report that the Prototype Fund has "pre-selected" my project to add JMAP support to K-9 Mail for funding. I still have to complete the formal application and then the project will probably start in September.

[bortzmeyer]

The standard has just been published: RFC 8621 https://www.rfc-editor.org/info/rfc8621

[cketti]

Short update: The project funding was approved and I'll be working on this for the next 6 months.

[marclaporte]

@cketti The great news was published here: https://jmap.io/news.html#k-9-mail-is-working-on-adding-jmap-support

If you have any updates, we are very interested :-)

Thanks!

[cketti]

The 6 months are up. The repository now contains a module called k9mail-jmap that is a version of the K-9 Mail app with rudimentary support for JMAP. The usability is not great and I don't plan on making APKs of it available. People interested in the current state will have to build the app themselves.

I created a JMAP milestone in the issue tracker with things that have to be implemented before I feel comfortable to include the JMAP code in the main app.

I plan to continue working on JMAP support, but I don't consider it a blocker for the next stable version of K-9 Mail. So it might be a while before I'll get back to it.

[doctorlard]

This is something I would like to contribute to; I'm considering moving (some of) my mail to Fastmail, so I can test it. This should probably depend on the updated UnifiedPush issue #5165 (which is currently understandably locked as off-topic)

[cketti]

There's a milestone for adding JMAP support: https://github.com/thundernest/k-9/milestone/26

It's currently not a high priority and there's a significant amount of work left to get this into a state that is good enough to be included in the app.
If you want to contribute to this, please try to keep the pull requests at a reasonable size and don't try to make too many changes at once.

UnifiedPush is just one possible push mechanism that can be used with JMAP. It's an optional feature, not a requirement.

[quickfixdemon]

What's the status on JMAP support?

[kewisch]

JMAP support is not on our immediate roadmap, therefore this unfortunately isn't something we'll be getting to soon. Given the scope of this project it might be worth creating an idea on https://mzla.link/tb-android-connect that others can upvote. I'd love to see broader adoption of JMAP from email providers to support the urgency as well.

[r0bbie]

Like others am hopeful to see JMAP support become a priority in future - we really need a solid mobile client.

There's an existing idea here - https://connect.mozilla.org/t5/ideas/jmap-support-or-similar-for-thunderbird/idi-p/28974 for Thunderbird, I guess a separate one should be setup for support in K9?

[kewisch]

Yes, a separate idea for Android would be great, you can link to the other idea (and this issue) and the connect folks will do the right things. Also note that it doesn't need to be on the Thunderbird for Android roadmap for others to work on. If someone want to take a few small steps towards JMAP they are certainly welcome to!