Why sessions matter in Django - See It in Action

Why sessions matter

📖 Scenario: You are building a simple Django web app where users can add items to a shopping cart. Since HTTP is stateless, the app needs a way to remember the cart contents as the user browses different pages.Sessions help keep track of user data between requests without requiring login. This project will show how to use Django sessions to store and retrieve cart items.

🎯 Goal: Build a Django view that uses sessions to store a list of cart items. The user can add items, and the session remembers them across page visits.

📋 What You'll Learn

Create a Django view function called add_to_cart that adds an item to the session cart list.

Initialize the cart list in the session if it does not exist.

Add a new item string to the session cart list.

Save the session after updating the cart.

Return a simple HTTP response confirming the item was added.

💡 Why This Matters

🌍 Real World

Websites use sessions to remember user data like shopping carts, login status, or preferences across multiple pages.

💼 Career

Understanding sessions is essential for backend web developers to manage user state and build interactive web applications.

1

Set up the initial Django view function

Create a Django view function called add_to_cart that takes request as a parameter and returns an HttpResponse with the text 'Item added to cart'. Import HttpResponse from django.http.

Django

from django.http import HttpResponse

# Create the add_to_cart view function
# Your code here

Need a hint?

Remember to import HttpResponse and define a function named add_to_cart that returns a simple response.

2

Initialize the cart list in the session

Inside the add_to_cart function, check if 'cart' exists in request.session. If not, create it as an empty list. Use if 'cart' not in request.session: and set request.session['cart'] = [].

Django

from django.http import HttpResponse

def add_to_cart(request):
    # Initialize 'cart' in session if it does not exist
    # Your code here
    return HttpResponse('Item added to cart')

Need a hint?

Use if 'cart' not in request.session: to check and then assign an empty list to request.session['cart'].

3

Add an item to the session cart list

Still inside add_to_cart, append the string 'apple' to the request.session['cart'] list. Use request.session['cart'].append('apple').

Django

from django.http import HttpResponse

def add_to_cart(request):
    if 'cart' not in request.session:
        request.session['cart'] = []
    # Add 'apple' to the cart list in session
    # Your code here
    return HttpResponse('Item added to cart')

Need a hint?

Use the append method on request.session['cart'] to add the string 'apple'.

4

Save the session after updating the cart

After appending the item, call request.session.modified = True to tell Django the session data changed. Keep the existing return statement.

Django

from django.http import HttpResponse

def add_to_cart(request):
    if 'cart' not in request.session:
        request.session['cart'] = []
    request.session['cart'].append('apple')
    # Mark session as modified
    # Your code here
    return HttpResponse('Item added to cart')

Need a hint?

Set request.session.modified = True after changing the session list to save changes.