jamiejackherer / quart-login

Quart user session management.

Quart-Login

Quart-Login provides user session management for Quart. It handles the common tasks of logging in, logging out, and remembering your users' sessions over extended periods of time.

Quart-Login is not bound to any particular database system or permissions model. The only requirement is that your user objects implement a few methods, and that you provide a callback to the extension capable of loading users from their ID.

Installation

Install the extension with pip:

$ pip install git+https://github.com/jamiejackherer/quart-login.git

Usage

Once installed, the Quart-Login is easy to use. Let's walk through setting up a basic application. Also please note that this is a very basic guide: we will be taking shortcuts here that you should never take in a real application.

To begin we'll set up a Quart app:

import quart

app = quart.Quart(__name__)
app.secret_key = 'super secret string'  # Change this!

Quart-Login works via a login manager. To kick things off, we'll set up the login manager by instantiating it and telling it about our Quart app:

import quart_login

login_manager = quart_login.LoginManager()

login_manager.init_app(app)

To keep things simple we're going to use a dictionary to represent a database of users. In a real application, this would be an actual persistence layer. However it's important to point out this is a feature of Quart-Login: it doesn't care how your data is stored so long as you tell it how to retrieve it!

# Our mock database.
users = {'[email protected]': {'password': 'secret'}}

We also need to tell Quart-Login how to load a user from a Quart request and from its session. To do this we need to define our user object, a user_loader callback, and a request_loader callback.

class User(quart_login.UserMixin):
    pass


@login_manager.user_loader
def user_loader(email):
    if email not in users:
        return

    user = User()
    user.id = email
    return user


@login_manager.request_loader
def request_loader(request):
    email = request.form.get('email')
    if email not in users:
        return

    user = User()
    user.id = email
    return user

Now we're ready to define our views. We can start with a login view, which will populate the session with authentication bits. After that we can define a view that requires authentication.

@app.route('/login', methods=['GET', 'POST'])
def login():
    if quart.request.method == 'GET':
        return '''
               <form action='login' method='POST'>
                <input type='text' name='email' id='email' placeholder='email'/>
                <input type='password' name='password' id='password' placeholder='password'/>
                <input type='submit' name='submit'/>
               </form>
               '''

    email = quart.request.form['email']
    if email in users and quart.request.form['password'] == users[email]['password']:
        user = User()
        user.id = email
        quart_login.login_user(user)
        return quart.redirect(quart.url_for('protected'))

    return 'Bad login'


@app.route('/protected')
@quart_login.login_required
def protected():
    return 'Logged in as: ' + quart_login.current_user.id

Finally we can define a view to clear the session and log users out:

@app.route('/logout')
def logout():
    quart_login.logout_user()
    return 'Logged out'

We now have a basic working application that makes use of session-based authentication. To round things off, we should provide a callback for login failures:

@login_manager.unauthorized_handler
def unauthorized_handler():
    return 'Unauthorized', 401

Documentation for Quart-Login is available on ReadTheDocs. For complete understanding of available configuration, please refer to the source code.

Contributing

We welcome contributions! If you would like to hack on Quart-Login, please follow these steps:

1. Fork this repository
2. Make your changes
3. Install the dev requirements with pip install -r requirements/dev.txt
4. Submit a pull request after running tox (ensure it does not error!)

Please give us adequate time to review your submission. Thanks!