Implement CalDAV-Managed Attachments (RFC 8607)

[AnorBanantje]

Is your feature request related to a problem? Please describe.

Hey, i installed Calendar 4.3.0 (Manual Way) on my Nextcloud server, adding attachments to events through web interface works but when i want to add attachment through aCalendar+ which normally support attachments with davx5.
Attachments are added through aCalendar+ and are available on aCalendar+ but is not synced to nextcloud calendar (Event is synced).

Describe the solution you'd like

DAVx5 support to Extended event properties:
https://manual.davx5.com/integration.html#extended-event-properties

Could be possible to implement attachments synchronisation in this way through DAVx5?

Describe alternatives you've considered

No response

Additional context

No response

[tcitworld]

The page you've linked to refers to DAVx5 <-> Android app compatibility, not DAVx5 <-> CalDAV Server compatibility.

It's unclear from the release notes if DAVx5 has brought RFC 8607 support (see #4251 (comment) and #4251 (comment)). In any case, that's what Nextcloud currently misses, even though #4251 is available.

cc @devvv4ever

[devvv4ever]

Currently we don't have support for Managed Attachments in DAVx5 either. It is however on our "This will definitely come to DAVx5"- to do list :) It was a bit post-poned since we now bundling forces to bring WebDAV (+CalDAV) Push to life first. This is our main goal for the next months.

Attachment support will be on the list after the Push I think. We primarily want to support Managed Attachments, where the server is managing the file. This would be the best way I think and we will get in touch with Nextcloud people to possibly coordinate an implementation for this at maybe the same time as we implement it in DAVx5 so that it can get to people on Android without much delay.

[jakobroehrl]

Maybe it would make sense to add a link to the attached file in the description so on mobile the user can click on the link and open the attachment?

[KaeTuuN]

@devvv4ever Any news/ticket/timeline on that now?

[devvv4ever]

WebDAV Push is on a good way, and we'll probably start on support for attachments after this as our next "bigger" project.