Bad request is returning 500 status code instead of 400

[MrRace]

1. When post a bad request that should be a json, how can I define the response for the client？ It seems just reply "500 Internal Server Error" now. When the client post a request that is not json format, how can I tell the client with the response?
2. If I do not set the -H "Content-Type: application/json", but the request data is standard json format, the payload in the server is empty. I just print the payload in the predict :

        print("payload type=", type(payload))
        print("payload=", payload)

the print result are below:

payload type= starlette.datastructures.FormData
payload= FormData([]) # it is empty, why?

why the body get by the server is empty?
Thanks a lot!

[RobertLucian]

@MrRace thank you a lot for reporting this. Indeed, this doesn't appear to be the right behavior for the webserver:

1. When a post request with a malformed JSON is made, a 400 error code should be returned. Instead, it gets a 500.
2. When the content-type is not set (i.e."Content-Type: "), your payload parameter should be a bytes object.

Also, when the user doesn't set the content-type for a curl request, curl will automatically set it to multipart/form. This can explain why you are getting a starlette.datastructures.FormData object. I presume you were using the curl utility for this. Check this out:
https://stackoverflow.com/questions/37718308/what-is-default-header-content-type-for-http-post-method-in-curl-form

[RobertLucian]

@MrRace we've created PR #1212 to address this problem.