Modular use of flask-login

[artgoldberg]

I'm a big proponent of modular code because I think it's easier to design, write, test and maintain.

Therefore, I'd like to make modular use of flask-login. That is, I'd like to create a Python module (file) that defines all the generic functions and decorators described in the Usage documentation, have the Flask app factory initialize it with the app, and then use the decorators, like login_required that it defines.

But I don't see an obvious way to do this because of the interdependencies between the flask-login code and the Flask app factory.

I welcome any advice on how to achieve the modularity I want, or an argument that the modularity I want cannot be reasonably achieved.

Thanks
Arthur

[artgoldberg]

Hi Folks

Thanks for your great work.

I'm trying to stimulate a response to my question by adding this comment because I'd love to be able to put (almost all) of my code that uses flask-login in a Python module that's separate from the app factory.

Thanks
Arthur

[davidism]

It's the same pattern as any other Flask extension.

login = LoginManager()

def create_app():
    app = Flask(__name__)
    login.init_app(app)
    return app

Now you can import login anywhere without circular dependencies.

[artgoldberg]

Thanks David @davidism . I understand that snippet.

But I'm trying to make the custom login code modular. Using the example in the Project description, how would I put this code in custom_login.py:

# Our mock database.
users = {'foo@bar.tld': {'password': 'secret'}}

class User(flask_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

@app.route('/login', methods=['GET', 'POST'])
def login():
    if flask.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 = flask.request.form['email']
    if email in users and flask.request.form['password'] == users[email]['password']:
        user = User()
        user.id = email
        flask_login.login_user(user)
        return flask.redirect(flask.url_for('protected'))

    return 'Bad login'

and then use @flask_login.login_required in the app factory?

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

Thanks
Arthur

PS. How do you tell Markdown to highlight Python's syntax?

[davidism]

If you have an app object, then you're not using the factory pattern. Remove that and use blueprints.

[artgoldberg]

Thanks @davidism . I'll do that when I have time.

Arthur