Flask-Login extension - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is the main purpose of the Flask-Login extension?

Flask-Login helps manage user sessions in Flask apps. It keeps track of logged-in users and handles login, logout, and session protection easily.

beginner

Which function in Flask-Login is used to log a user in?

The login_user() function logs a user in by creating a session for them.

beginner

What does the @login_required decorator do?

It protects routes so only logged-in users can access them. If a user is not logged in, it redirects them to the login page.

intermediate

How does Flask-Login identify the current user in a request?

Flask-Login provides a current_user proxy that represents the logged-in user or an anonymous user if no one is logged in.

intermediate

What must a user class implement to work with Flask-Login?

The user class must have these methods: <code>is_authenticated</code>, <code>is_active</code>, <code>is_anonymous</code>, and a method <code>get_id()</code> that returns a unique ID as a string.

Which Flask-Login function logs out the current user?

A logout_user()

B login_user()

C current_user()

D user_loader()

The logout_user() function ends the user session and logs the user out.

What does the user_loader callback do in Flask-Login?

A Loads a user from the database by ID

B Logs a user in

C Logs a user out

D Protects routes

The user_loader callback tells Flask-Login how to get a user object from a user ID stored in the session.

What happens if a non-logged-in user tries to access a route with @login_required?

A They get a 404 error

B They see the page anyway

C The app crashes

D They are redirected to the login page

The @login_required decorator redirects users who are not logged in to the login page.

Which attribute tells if a user is logged in or not?

A current_user.is_active

B current_user.is_authenticated

C current_user.get_id()

D current_user.is_anonymous

is_authenticated is True if the user is logged in, False otherwise.

What type of value should get_id() return?

A A list of permissions

B A boolean

C A unique string identifying the user

D An integer count

get_id() must return a unique string that identifies the user for session management.

Explain how Flask-Login manages user sessions in a Flask app.

Think about how users log in, stay logged in, and how routes can be protected.

Describe the requirements for a user class to work with Flask-Login.

Focus on the methods Flask-Login expects to check user status and identity.