How to use an authentication decorator from within a blueprint in flask

Question

I would like to use the following basic authentication decorator in my blueprints:

def requires_auth(func):
    @wraps(func)
    def decorated(*args, **kwargs):
        request_auth = request.authorization
        if not request_auth or not auth.authenticate(request_auth.username, request_auth.password):
            return api.response_auth_failed()
        return func(*args, **kwargs)
    return decorated

And in the blueprint:

@bp.route("/")
@requires_auth
def root():
  return "root"

But it relies on the flask_peewee.auth module which also requires a db instance, which requires the app instance as the Database() module uses the app for configuration:

db = Database(app)
auth = Auth(app, db)

I had this working before when the application was simpler by instantiating all of this in the one app.py file, but now I'd like to organize it a little better.

Would it be possible to move my db.Model definitions, and the above requires_auth decorator to another file, say a db_models.py module, and import the requires_auth decorator into my individual Blueprint definitions? How can I do that if I need access to the app object to create the db object?

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Edit: I've reorganized my app to look like this: http://charlesleifer.com/blog/structuring-flask-apps-a-how-to-for-those-coming-from-django/ I put the requires_auth function in my auth.py module an I can import and use it in the view.py but when I try and import it into one of my blueprints it fails. I think it's because auth module imports the app module, and the blueprint is extending the app module so I'm getting a circular import. Any ideas?

Answer 1

As you've noted, I think the problem is your module organization. What if you create a decorators module that contains requires_auth?

Then you will structure your imports to flow like:

1. app.py (instantiate app & db)
2. auth.py (instantiate auth, imports from app.py)
3. api.py (instantiate api, imports from app.py)
4. decorators.py (define requires_auth, imports from auth and api)
5. blueprints/views.py (imports from app.py, auth.py, api.py, decorators.py)
6. main.py (imports app, auth, api, decorators, blueprints) and is entry-point for application.