Flask token based authentication

flask_login_token.py

# Author: Gouthaman Balaraman
# http://gouthamanbalaraman.com/minimal-flask-login-example.html

from flask import Flask, Response
from flask.ext.login import LoginManager, UserMixin, login_required


app = Flask(__name__)
login_manager = LoginManager()
login_manager.init_app(app)


class User(UserMixin):
    # proxy for a database of users
    user_database = {"JohnDoe": ("JohnDoe", "John"),
               "JaneDoe": ("JaneDoe", "Jane")}

    def __init__(self, username, password):
        self.id = username
        self.password = password

    @classmethod
    def get(cls,id):
        return cls.user_database.get(id)


@login_manager.request_loader
def load_user(request):
    token = request.headers.get('Authorization')
    if token is None:
        token = request.args.get('token')

    if token is not None:
        username,password = token.split(":") # naive token
        user_entry = User.get(username)
        if (user_entry is not None):
            user = User(user_entry[0],user_entry[1])
            if (user.password == password):
                return user
    return None


@app.route("/",methods=["GET"])
def index():
    return Response(response="Hello World!",status=200)


@app.route("/protected/",methods=["GET"])
@login_required
def protected():
    return Response(response="Hello Protected World!", status=200)


if __name__ == '__main__':
    app.config["SECRET_KEY"] = "ITSASECRET"
    app.run(port=5000,debug=True)

LICENSE

The MIT License


Further resources on the MIT License
Copyright 2014 Gouthaman Balaraman

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

This is the gist from my blog post Flask login tutorial.

It might be better to use an else instead of an if not on line 33, i.e.:

if token is None:
    # do stuff
else:
    # do other stuff

instead of

if token is None:
    # do stuff
if token is not None:
    # do other stuff

if token is none, how to send user to login page?

if token is none, how to send user to login page?

`if token is None:
return redirect(url_for('login'))
else:

`