Login form and verification in Flask - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is the purpose of a login form in a Flask web application?

A login form collects user credentials like username and password to verify the user's identity before granting access to protected parts of the website.

beginner

Which Flask extension is commonly used to manage user sessions and authentication?

Flask-Login is a popular extension that helps manage user sessions, handle login/logout, and protect routes that require authentication.

intermediate

In Flask, how do you securely check if a user's password is correct?

You use password hashing functions like Werkzeug's generate_password_hash to store hashed passwords and check_password_hash to verify the entered password against the stored hash.

beginner

What is the role of the @app.route decorator in creating a login form?

The @app.route decorator defines the URL endpoint for the login page and specifies which HTTP methods (GET, POST) the function will handle to display the form and process login data.

beginner

Why should you use POST method instead of GET for submitting login forms?

POST hides the submitted data in the request body, making it more secure than GET, which appends data to the URL and can expose sensitive information like passwords.

Which Flask function helps you protect routes so only logged-in users can access them?

A @login_required

B @app.route

C render_template()

D flash()

The @login_required decorator from Flask-Login restricts access to routes to only authenticated users.

What does the function check_password_hash() do in Flask?

A Hashes a new password

B Checks if a password matches a stored hash

C Encrypts user data

D Creates a user session

check_password_hash() compares a plain password with a stored hashed password to verify if they match.

Which HTTP method should be used to submit login credentials securely?

A POST

B PUT

C GET

D DELETE

POST sends data in the request body, keeping credentials hidden from the URL, unlike GET.

What is the main purpose of Flask-Login?

A To create HTML forms

B To style web pages

C To manage user authentication and sessions

D To connect to databases

Flask-Login helps manage user login states and session handling.

Where do you define the URL path for the login page in Flask?

A In the database

B In the HTML template

C In the CSS file

D Using @app.route decorator

The @app.route decorator sets the URL endpoint for the login view function.

Explain how to create a simple login form in Flask and verify user credentials.

Think about the steps from showing the form to logging the user in.

Describe why password hashing is important in login verification and how Flask supports it.

Consider what happens if someone steals your password database.