How to use Custom built REST API to authenticate airflow webserver login?

Question

I am using Airflow 2.0.1

I have created one REST API as below which takes username and password and returns if user is authenticated or not.

API: http://localhost:port/api/authenticate

Request Body: {"username": "user", "password": "pswd"}

Now, i have to use this api in airflow code to authenticate users for the webserver login.

I have tried to follow "Roll your own API authentication" section in https://airflow.apache.org/docs/apache-airflow/stable/security/api.html

But i am still not very clear on what needs to be done.

Any help here is highly appreciated. Let me know in case you need any further details.