How to get query params in fast api from POST request

Question

Client might send multiple query params like:

# method = POST 
http://api.com?x=foo&y=bar

I need to get all the query params and extract it as a string x=foo&y=bar from the POST request.

Is there a way to do this on fast api? I could not find it on their docs.

NOTE :

We are not sure of the names of the params before hand.