How to subscribe to collections

[rfc2822]

How should subscriptions be registered at the WebDAV server? Our current ideas are

1. like Managed Attachments (POST with ?action= on collection URL)
2. with a separate URL space for the subscriptions, where they can be managed in a RESTful way
   • REST on /<collection>/push-subscriptions
   • REST on (/<principal>?)/push-subscriptions (would allow subscribing to multiple collections in one request)
3. (Edit) POST on /<collection> with subscription info in body, like to create a WebDAV share
4. Other?

[ArnyminerZ]

Based on RFC-8030, I'd either provide a custom endpoint such as /push/subscribe for example, and then pass the collection ID in the body or some header, for example; or provide an endpoint for each collection such as /push/collections/<collection> to which you can POST for example.

[tcitworld]

Why not create the subscription directly on the collection itself, and use the payload document type?

POST /<collection>
Content-Type: application/xml; charset="utf-8"

<create-subscription xmlns="DAV:Push">
  <transport>
   <!-- ...implementation-details -->
  </transport>
</create-subscription>

That's similar to how SabreDAV & Nextcloud create collection shares.

I don't think using the action query param is the right way to handle things here. In the case of managed attachments it's only used to avoid describing the action in the payload, which is reserved to the attachment data itself.

[rfc2822]

Sounds like an interesting alternative, I'll try to find more information about it!