Empty/unknown POST body returning 200

[donaldgray]

If I make a call to POST /convert with an empty ({}), or unrecognised body I get a 200 response code back, with the following JSON:

{
    "message": "Unknown operation",
    "status": "error"
}

This should be a non 2xx (400?) response.

[donaldgray]

This also happens if requesting "derivatives-only" and source is not a JP2