Why a field-scoped operation was refused, independent of the wording of message, so a host can pick an HTTP status without parsing text: - required — the field is empty. - conflict — the value collides with an existing entry. - not_found — the referenced entry does not exist. - invalid — the value has the wrong shape or an unsupported value.
-
REQUIRED(value:'required') -
CONFLICT(value:'conflict') -
NOT_FOUND(value:'not_found') -
INVALID(value:'invalid')