Python

Gravatar for andres.aguiar@auth0.com
By Andres Aguiar
Auth0

You can get started by either downloading the complete sample or following the tutorial steps to integrate Auth0 with an existing application.

Sample Project

Download a sample project specific to this tutorial configured with your Auth0 API Keys.

System Requirements
  • Python 2.7, 3.0 and up
  • Flask 0.10.1 and up
  • Python-dotenv 0.6.5 and up
  • Requests 2.3.0 and up
  • Authlib 0.6
  • Six 1.10.0 and up
Show requirements

Before you start

This guide walks you through setting up authentication and authorization in your Python apps with Auth0. If you are new to Auth0 we suggest you check our Overview. For a complete picture of authentication and authorization for regular web apps, check our Single Sign-On for Regular Web Apps documentation.

Auth0 uses OAuth. If you want to learn more about the OAuth flows used by regular web apps, read about Authentication for Server-side Web Apps.

Get Your Application Keys

When you signed up for Auth0, you created a new application.

You will need some details about this application to communicate with Auth0. You can get them from the Application Settings in the Auth0 dashboard.

You need the following information:

  • Client ID
  • Domain

If you download the sample from the top of this page, these details are filled out for you. If you have more than one application in your account, the sample comes with the values for your Default App.

App Dashboard

Configure Callback URLs

A callback URL is a URL in your application where Auth0 redirects the user after they have authenticated.

You need to whitelist the callback URL for your app in the Allowed Callback URLs field in your Application Settings. If you do not set any callback URL, your users will see a mismatch error when they log in.

If you are following along with the sample project you downloaded from the top of this page, Callback URL should be set to http://localhost:3000/callback.

Add the Dependencies

This example uses Flask and the Authlib OAuth library.

Add the following dependencies to your requirements.txt and run pip install -r requirements.txt.

// /requirements.txt

flask
python-dotenv
requests
authlib
six

Initialize Authlib

Create a file named server.py, and instantiate an application with your client keys, scopes, and OAuth endpoints.

# /server.py
    
from functools import wraps
import json
from os import environ as env
from werkzeug.exceptions import HTTPException

from dotenv import load_dotenv, find_dotenv
from flask import Flask
from flask import jsonify
from flask import redirect
from flask import render_template
from flask import session
from flask import url_for
from authlib.flask.client import OAuth
from six.moves.urllib.parse import urlencode
import requests
    
app = Flask(__name__)

oauth = OAuth(app)

auth0 = oauth.register(
    'auth0',
    client_id='YOUR_CLIENT_ID',
    client_secret='YOUR_CLIENT_SECRET',
    api_base_url='https://YOUR_AUTH0_DOMAIN',
    access_token_url='https://YOUR_AUTH0_DOMAIN/oauth/token',
    authorize_url='https://YOUR_AUTH0_DOMAIN/authorize',
    client_kwargs={
        'scope': 'openid profile',
    },
)

Add the Auth0 Callback Handler

This handler exchanges the code that Auth0 sends to the callback URL for an access_token and an id_token.

The access_token will be used to call the /userinfo endpoint to get the user profile. After the user information is obtained, store then in the flask session.

# /server.py

# Here we're using the /callback route.
@app.route('/callback')
def callback_handling():
    # Handles response from token endpoint
    resp = auth0.authorize_access_token()

    url = 'https://YOUR_AUTH0_DOMAIN/userinfo'
    headers = {'authorization': 'Bearer ' + resp['access_token']}
    resp = requests.get(url, headers=headers)
    userinfo = resp.json()

    # Store the tue user information in flask session.
    session['jwt_payload'] = userinfo

    session['profile'] = {
        'user_id': userinfo['sub'],
        'name': userinfo['name'],
        'picture': userinfo['picture']
    }

    return redirect('/dashboard')

Trigger Authentication

Add a /login route that uses the Authlib client instance to redirect the user to the login page.

# /server.py

@app.route('/login')
def login():
    return auth0.authorize_redirect(redirect_uri='YOUR_CALLBACK_URL', audience='https://YOUR_AUTH0_DOMAIN/userinfo')

Create a home.html file in a /template folder. Add a link to the /login route.

<div class="login-box auth0-box before">
    <img src="https://i.cloudup.com/StzWWrY34s.png" />
    <h3>Auth0 Example</h3>
    <p>Zero friction identity infrastructure, built for developers</p>
    <a class="btn btn-primary btn-lg btn-login btn-block" href="/login">Log In</a>
</div>

Logout

To log the user out, you have to clear the data from the session, and redirect the user to the Auth0 logout endpoint. You can find more information about this in our logout documentation.

# /server.py

@app.route('/logout')
def logout():
    # Clear session stored data
    session.clear()
    # Redirect user to logout endpoint
    params = {'returnTo': url_for('home', _external=True), 'client_id': 'YOUR_CLIENT_ID'}
    return redirect(auth0.base_url + '/v2/logout?' + urlencode(params))

Please take into consideration that the return to URL needs to be in the list of Allowed Logout URLs in the settings section of the application as explained in our documentation

Check if the user is authenticated

Add the following decorator to your Flask app. Use it to decorate methods that require authentication.

You should import wraps first, adding the following line to your server.py file: from functools import wraps.

# /server.py

def requires_auth(f):
  @wraps(f)
  def decorated(*args, **kwargs):
    if 'profile' not in session:
      # Redirect to Login page here
      return redirect('/')
    return f(*args, **kwargs)
    
  return decorated

Showing the User Profile

Add a /dashboard route to server.py that will render the user information stored in the Flask session.

Decorate it with @requires_auth. It will only be accessible if the user has been authenticated.

# /server.py

@app.route('/dashboard')
@requires_auth
def dashboard():
    return render_template('dashboard.html',
                           userinfo=session['profile'],
                           userinfo_pretty=json.dumps(session['jwt_payload'], indent=4))

Add a dashboard.html file in a /template folder to display the user information.

Add a link to allow users to Log Out.

<div class="logged-in-box auth0-box logged-in">
    <h1 id="logo"><img src="//cdn.auth0.com/samples/auth0_logo_final_blue_RGB.png" /></h1>
    <img class="avatar" src="{{userinfo['picture']}}"/>
    <h2>Welcome {{userinfo['name']}}</h2>
    <pre>{{userinfo_pretty}}</pre>
    <a class="btn btn-primary btn-lg btn-logout btn-block" href="/logout">Logout</a>
</div>
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