[NEW] Endpoint to retrieve message read receipts

[MarcosSpessatto]

Closes #9904.
Added endpoint to retrieve message read receipts.

[rafaelks]

I added it to 0.63 because this is something we'll need on the mobile apps.

[winterstefan]

May I humbly ask how exactly you would use this endpoint for a (huge) list of messages & rooms?

we'll need on the mobile apps.

I may have a similar use-case (adding it to a custom chat client based on the Realtime API) and therefore thought about how & when the pull endpoint ('get read status for one message') should be triggered.

Wouldn't some kind of push (e.g. via WebSocket @ Realtime API) make sense to propagate the new read status to other room members?

[rafaelks]

@winterstefan That's a great question. Basically, this request will only happen when some user wants to see who read that message. The indication of read is already present in the Message object with the read property.

The RealTime API will indicate the update on the message (read becomes true), but we don't need to know who read it for now.

[winterstefan]

Thank you very much for your fast reply, @rafaelks!

The RealTime API will indicate the update on the message (read becomes true), but we don't need to know who read it for now.

Ah, got it - there it is. I was focussing on subscriptions.

Just tested that with three users in a room - works great! 👍
When all users have read a certain message, the stream-room-message sends a changed event where the message.unread has been removed.