Create a requirements.txt file in your project directory:

# 📁 requirements.txt -----

flask>=2.0.3
python-dotenv>=0.19.2
authlib>=1.0
requests>=2.27.1

Run the following command from your shell to enable these dependencies in your project:

pip install -r requirements.txt

Next, create an .env file in your project directory. This file will hold your client keys and other configuration details.

# 📁 .env -----

AUTH0_CLIENT_ID={yourClientId}
AUTH0_CLIENT_SECRET={yourClientSecret}
AUTH0_DOMAIN={yourDomain}
APP_SECRET_KEY=

• Generate a string for APP_SECRET_KEY using openssl rand -hex 32 from your shell.

Next, set up your application. Create a server.py file in your project directory - this file will contain your application logic.

Import all the libraries your application needs.

Load the configuration .env file you made in the previous step.

Configure Authlib to handle your application's authentication with Auth0. To learn more about the configuration options available for Authlib's OAuth register() method from their documentation.

In this example, you will add four routes to the application: login, callback, logout, and home.

When visitors to your app visit the /login route, your application will route them to the Auth0 login page.

After your users log in with Auth0, your application will route them to the /callback route. This route saves the session for the user and bypasses the need for them to login again when they return.

The /logout route signs users out from your application. This route clears the user session in your app and redirects to the Auth0 logout endpoint to ensure the session is no longer saved. Then, the application redirects the user to your home route.

Your / home route either renders an authenticated user's details or allows visitors to sign in.

Next, create the template file used in the home route (during render_template() calls).

Create a new sub-directory in your project folder named templates, and create home.html in the directory. Paste the content from the right into that file.

To run your application, navigate to the root of your project directory and open a terminal. Run the following command:

python3 server.py