Spring security OAuth2 request as object instead of query parameters - spring

Question

I want to customise OAuth Endpoint URI's.
I want to sent parameters in post body instead of query params.
now my request is like -
example.com/oauth/token?grant_type=password&client_id={CLIENT_ID}&client_secret={CLIENT_SECRET}&username={USERNAME}&password={PASSWORD}
But I want it like this.
example.com/oauth/token
Request body -
{
grant_type=password,
client_id={CLIENT_ID},
client_secret={CLIENT_SECRET},
username={USERNAME},
password={PASSWORD}
}
How should I do it?

Answer 1

The token endpoint of a properly-implemented authorization server does NOT accept GET requests because RFC 6749, "3.2. Token Endpoint" says as follows:
The client MUST use the HTTP "POST" method when making access token requests.
So, your authorization server's token endpoint should reject GET requests.
RFC 6749, "4.3. Resource Owner Password Credentials Grant" says that request parameters of a token request using Resource Owner Password Credentials flow should be embedded in the request body in the format of "application/x-www-form-urlencoded". The following is an excerpt from "4.3.2. Access Token Request".
POST /token HTTP/1.1
Host: server.example.com
Authorization: Basic czZCaGRSa3F0MzpnWDFmQmF0M2JW
Content-Type: application/x-www-form-urlencoded
grant_type=password&username=johndoe&password=A3ddj3w
Therefore, you don't have to customize your authorization server. If the server is implemented correctly, its token endpoint accepts POST requests.

Answer 2

The token endpoint created by spring-oauth2 already deals with POST as well.
It would be hard to customize it to accept a JSON request body, because the TokenEndpoint class expects all the params as #RequestParam params.
However, if your concern is about security (as HTTPs does not secure query parameters) you indeed can send the request parameters through post. It is just a matter of sending the request in the form "form-data" or "x-www-form-urlencoded". These are 2 ways of sending arbitrary key-value parameters in the request body, in a way that appears to the server as they are regular request parameters. So it is a matter of making your client using this.
Also, note that in spring-oauth2 it is possible to disable the GET endpoint, this way forcing your clients to use POST with one of the ways above.