Currently requests made with the PUT, POST, and DELETE verbs all return 404, even if made against a file which exists.
It seems like POST and DELETE should return 200 for files which exist and 404 otherwise. PUT should always return 200. In all three cases, no actual operations should be performed by the server, just accept-and-ignore so that HTTP response is at least "happy path" so clients can issue mutating requests and have them succeed for the main use cases.