Flask-CAS is a Flask extension which makes it easy to authenticate with a CAS Server (v2.0+).
The Central Authentication Service (CAS) is a single sign-on protocol for the web. Its purpose is to permit a user to access multiple applications while providing their credentials (such as userid and password) only once. It also allows web applications to authenticate users without gaining access to a user's security credentials, such as a password. The name CAS also refers to a software package that implements this protocol.
Want to see it in action? Here is a live demo that lets you authenticate against your favorite CAS Server!
http://flask-cas-extension-demo.cameronbwhite.com/
Flask-CAS is available on PyPI! You can install it with pip.
pip install Flask-CASIf you want to do it the hard way you can clone the repository and install Flask-CAS in a virtualenv.
- Clone it
git clone [email protected]:cameronbwhite/Flask-CAS.git - Enter it
cd Flask-CAS - Create a virtualenv and enter it (Optional)
virtualenv venv && source venv/bin/activate - Install it
python setup.py install
After Flask-CAS is installed you will be able to import the flask_cas
packages. There is only one thing you care about inside the package
which is the CAS class.
from flask_cas import CASThere are two ways to use the CAS class.
- Add the application object at construction time
app = Flask(__name__)
CAS(app)- Or initialize the application with
CAS.init_app
cas = CAS()
app = Flask(__name__)
cas.init_app(app)The CAS class will add two routes /login/ and /logout/. You can
prefix these routes if you pass a second argument to the CAS
constructor or init_app depending on the method you choose.
The /login/ route will redirect the user to the CAS specified by the
CAS_SERVER configuration value. If login is successful the user will
be redirect to the endpoint specified by the CAS_AFTER_LOGIN
configuration value, and the logged in user's username will be store
in the session under the key specified by the CAS_USERNAME_SESSION_KEY
configuration value. If attributes are available, they will be stored
in the session under the key specified by the
CAS_ATTRIBUTES_SESSION_KEY
The /logout/ route will redirect the user to the CAS logout page and
the username and attributes will be removed from the session.
For convenience you can use the cas.login and cas.logout
functions to redirect users to the login and logout pages.
from flask_cas import login
from flask_cas import logoutIf you would like to require that a user is logged in before continuing
you may use the cas.login_required method.
from flask_cas import login_required
app.route('/foo')
@login_required
def foo():
pass| Key | Description | Example |
|---|---|---|
| CAS_SERVER | URL of CAS | 'http://sso.pdx.edu' |
| Key | Default |
|---|---|
| CAS_TOKEN_SESSION_KEY | _CAS_TOKEN |
| CAS_USERNAME_SESSION_KEY | CAS_USERNAME |
| CAS_ATTRIBUTES_SESSION_KEY | CAS_ATTRIBUTES |
| CAS_LOGIN_ROUTE | '/cas' |
| CAS_LOGOUT_ROUTE | '/cas/logout' |
| CAS_VALIDATE_ROUTE | '/cas/serviceValidate' |
| CAS_AFTER_LOGOUT | None |
| CAS_AFTER_LOGIN | None -> redirects to '/'. Can be relative path or hard URL |
import flask
from flask import Flask
from flask_cas import CAS
from flask_cas import login_required
app = Flask(__name__)
cas = CAS(app, '/cas')
app.config['CAS_SERVER'] = 'https://sso.pdx.edu'
app.config['CAS_AFTER_LOGIN'] = '/'
@app.route('/')
@login_required
def route_root():
return flask.render_template(
'layout.html',
username = cas.username,
display_name = cas.attributes['cas:displayName']
)