There is no spec-compliant way to remove remove/clear a user avatar

[dkanada]

I think it would be useful to be able to set an avatar to null again with an event, but I don't see the option anywhere in the android client. Is it just not implemented yet on android or is it not in the spec yet?

[turt2live]

Looks like it doesn't say it, but a PUT with avatar_url: null will get the job done. I've updated the title of this issue to represent the omission.

[dkanada]

I can't seem to find the API call to set a room avatar, does it work the same way? Also, would a null value be an empty string for the property or an empty json call? Haven't worked with the API on the android client yet, just want to make sure I understand correctly.

[bmarty]

@dkanada not sure it will work on Android, as null serialization is not enabled by default on the Rest client

[dkanada]

Is there any chance to get this working then? Since only certain API calls allow a null value, it could just be enabled where necessary, like setting newUrl in this method to accept a null value. Could also add an endpoint for deleting a user avatar.

/_matrix/client/r0/profile/{userId}/avatar_url/remove

[turt2live]

The API endpoint would be https://matrix.org/docs/spec/client_server/r0.4.0.html#put-matrix-client-r0-profile-userid-avatar-url where the avatar_url is specified as null, however that would be done. Issues/questions specific to riot-android should be directed at riot-android though, despite there being lack of documentation in the spec for this area.

[turt2live]

Actually, it looks like the spec allows one to post an empty object and achieve the same goal, it just doesn't say that. Changing this to a clarification and not an omission.

[bmarty]

@dkanada ,
Not without a specific change. As you can see, the constructor of ProfileRestClient call the super constructor with false for the last parameter (withNullSerialization)

[bmarty]

I think the best solution for a full Rest server should be to use the DELETE method for this API:
DELETE /_matrix/client/r0/profile/{userId}/avatar_url

[dkanada]

I didn't see too many delete calls in the client server API though, it seemed like you guys were trying to avoid them. Does the redact feature use delete for events?

Regardless, would an empty object work for this purpose, or maybe just an empty string for the avatar_url field? It hasn't been revisited yet but I would also like to add group icon removal as well, which would probably be a separate change.

[turt2live]

It's not that the spec tries to avoid DELETE, it's just that there's not a lot of use for it. Redacting doesn't use DELETE because redacting doesn't delete things, it redacts them which is an action. Events in matrix cannot be truly deleted.

An empty object would work as per my last comment. An empty string probably wouldn't have the effect you're looking for. Groups aren't in the spec yet, but I imagine they'll have similar semantics.

[turt2live]

So it turns out that the avatar_url is required, and we've decided that null isn't necessarily valid (https://github.com/matrix-org/matrix-doc/issues/2011). I guess an empty string would be the current way to do things, or possibly introducing a DELETE endpoint - I'd personally be in favour of a DELETE endpoint.

[KitsuneRal]

In whichever case, both user and room avatar cases should be addressed; and since in case of rooms an avatar is defined by a state event, introducing a DELETE endpoint would probably lead us to the long standing question of ability to remove other state events as well.

[dkanada]

I just found out group names (which I think are state events) can be removed so I agree that something should definitely be added to the spec for avatars as well.

[dkanada]

@turt2live any update on this one?

[jaller94]

Element Web resets avatars by sending an empty string.

[bmarty]

Related: element-hq/element-android#4254