ActivityPub C2S: Error 400 when posting non-activity objects not wrapped into a Create activity
When posting an object that is not an activity to the user's outbox, it is expected that the server wraps it in a Create activity (See https://www.w3.org/TR/activitypub/#object-without-create ).
Currently, Pleroma responds with an error 400 (Bad Request), with the message "Unhandled activity type". When wrapping the same item inside a Create activity, Pleroma accepts the request.
Ex: Unwrapped note causing an error:
{"@context":"https://www.w3.org/ns/activitystreams","type":"Note","to":["http://localhost:4000/users/test"],"cc":[],"summary":"Test note","content":"A small note"}When wrapped in a Create activity, no error, the note is created:
{"@context":"https://www.w3.org/ns/activitystreams","type":"Create","to":["http://localhost:4000/users/test"],"cc":[],"object":{"@context":"https://www.w3.org/ns/activitystreams","type":"Note","to":["http://localhost:4000/users/test"],"cc":[],"summary":"Test note","content":"A small note"}}Tested on commit 54997500 from develop.