Basic OAuth v2

What is it?

The Oauth v2 spec defines several authorization grant. This library implements the "Resource Owner Password Credentials Grant" as described in http://tools.ietf.org/html/draft-ietf-oauth-v2-31#section-4.3

Requirements:

• Flask
• Redis

Why using it?

The goal of this Grant is to replace the classic "HTTP Basic over SSL" widely used. With Oauth, you exchange your crendentials against a token.

This mechanism has several advantages:

• The client does not pass the full credentials for each request.
• The server does not check the username and password each time, it will only check the access token, this will reduce the database lookups.

Basic Oauth uses Redis to store the sessions.

Is it secure?

It would be stupid to use this mechanism without SSL. Even if the token is passed instead of the credentials, the credentials needs to be passed in clear text during the Authentication phase. Also, it can be problematic to lose the token.

To limit the risk of losing the token, every single token generated is signed using the User-Agent and the client IP address. If an attacker tries to re-use a stolen token, he will have to connect to the same IP and using the same User-Agent (browser version, OS, architecture) to get access. A wrong try will result in destroying the session.

How to use it?

Install basic_oauth from PYPI:

pip install basic_oauth

Create a sample WSGI app with Flask:

import flask
import basic_oauth

app = flask.Flask(__name__)

oauth = basic_oauth.BasicOauth(app)
oauth.mount_endpoint('login', '/login')
oauth.mount_endpoint('script', '/js/oauth_client.js')
oauth.credentials.append(('johndoe', 'foobar42'))
# You can declare "oauth.authenticate_handler" to plug your own
# database instead of using the in-memory credentials

@app.route('/')
@oauth.require
def hello(user_id):
    return 'Hello World!'

if __name__ == '__main__':
    app.debug = True
    app.run()

Checkout the "example" directory for a complete server/client example.