I have similar apps on Flask and FastAPI. When I do this curl requests with Flask, that is all right:
Without TLS:
curl -X POST -H "Content-Type: application/json" -d '{"method": "account.auth"}' http://X.X.X.X:5050/
{"error":0,"result":{"token":"XXX"}}
With TLS:
curl -X POST -H "Content-Type: application/json" -d '{"method": "account.auth"}' https://example.com:8443/api/
{"error":0,"result":{"token":"XXX"}}
!!! But with FastAPI I get another result:
Without TLS:
curl -X POST -H "Content-Type: application/json" -d '{"method": "account.auth"}' http://X.X.X.X:5050/
{"error":0,"result":{"token":"XXX"}}
With TLS:
curl -X POST -H "Content-Type: application/json" -d '{"method": "account.auth"}' https://example.com:8443/api/
Unsupported upgrade request.
How to fix problem with "Unsupported upgrade request."? And what is it? Flask are working with it normally.
This same issue usually seems to arise from incomplete uvicorn installations, but is usually related to websockets.
A solution for this issue might be to reinstall uvicorn with the recommended (by FastAPI) extras:
python3 -m pip uninstall uvicorn
python3 -m pip install uvicorn[standard]