Login_required decorator in Flask - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is the purpose of the login_required decorator in Flask?

The login_required decorator ensures that a user must be logged in to access a specific route or view. If the user is not logged in, they are redirected to the login page.

beginner

How do you apply the login_required decorator to a Flask route?

You place @login_required above the route function definition. For example:<br>

@app.route('/dashboard')<br>@login_required<br>def dashboard():<br>    return 'Welcome!'

beginner

Which Flask extension provides the login_required decorator?

The Flask-Login extension provides the login_required decorator to manage user sessions and protect routes.

beginner

What happens if a user who is not logged in tries to access a route protected by login_required?

They are redirected to the login page, usually specified by the login_view setting in Flask-Login. This prevents unauthorized access.

intermediate

Can you customize where users are redirected if they are not logged in when using login_required?

Yes, you can set the login page route by configuring login_manager.login_view in your Flask app. For example:<br>

login_manager.login_view = 'login'

What does the login_required decorator do in Flask?

A Encrypts user passwords

B Logs the user out automatically

C Creates a new user account

D Prevents access to a route if the user is not logged in

The login_required decorator restricts access to routes for users who are not logged in.

Which Flask extension must you install to use login_required?

A Flask-Login

B Flask-Mail

C Flask-WTF

D Flask-Migrate

login_required is provided by the Flask-Login extension.

If a user is not logged in and tries to access a protected route, what happens?

A They see a 404 error

B They are redirected to the login page

C They get access anyway

D The server crashes

Users not logged in are redirected to the login page when accessing routes with login_required.

How do you specify the login page URL for login_required redirection?

A By creating a <code>/login</code> route only

B By setting <code>app.secret_key</code>

C By setting <code>login_manager.login_view</code>

D By using <code>@app.before_request</code>

You configure login_manager.login_view to set the login page URL.

Where do you place the @login_required decorator in your Flask code?

A Above the route function

B Inside the route function

C After the route function

D In the HTML template

Decorators like @login_required go above the route function definition.

Explain how the login_required decorator works in Flask and why it is useful.

Think about what happens when a user tries to visit a page without logging in.

Describe the steps to protect a Flask route using login_required.

Consider setup and usage in code.