Creating an online shop project

Let's start with a new Django project to build an online shop. Your users will be able to browse through a product catalog and add products to a shopping cart. Finally, they will be able to check out the cart and place an order. This chapter will cover the following functionalities of an online shop:

• Creating the product catalog models, adding them to the administration site, and building the basic views to display the catalog
• Building a shopping cart system using Django sessions to allow users to keep selected products while they browse the site
• Creating the form and functionality to place orders on the site
• Sending an asynchronous email confirmation to users when they place an order

Open a shell and use the following command to create a new virtual environment for this project within the env/ directory:

python -m venv env/myshop

If you are using Linux or macOS, run the following command to activate your virtual environment:

source env/myshop...

Building a shopping cart

After building the product catalog, the next step is to create a shopping cart so that users can pick the products that they want to purchase. A shopping cart allows users to select products and set the amount they want to order, and then store this information temporarily while they browse the site, until they eventually place an order. The cart has to be persisted in the session so that the cart items are maintained during a user's visit.

You will use Django's session framework to persist the cart. The cart will be kept in the session until it finishes or the user checks out of the cart. You will also need to build additional Django models for the cart and its items.

Using Django sessions

Django provides a session framework that supports anonymous and user sessions. The session framework allows you to store arbitrary data for each visitor. Session data is stored on the server side, and cookies contain the session ID unless you use the cookie-based...

Registering customer orders

When a shopping cart is checked out, you need to save an order in the database. Orders will contain information about customers and the products they are buying.

Create a new application for managing customer orders using the following command:

python manage.py startapp orders

Edit the settings.py file of your project and add the new application to the INSTALLED_APPS setting, as follows:

INSTALLED_APPS = [
    # ...
    'shop.apps.ShopConfig',
    'cart.apps.CartConfig',
    'orders.apps.OrdersConfig',
]

You have activated the orders application.

Creating order models

You will need a model to store the order details and a second model to store items bought, including their price and quantity. Edit the models.py file of the orders application and add the following code to it:

from django.db import models
from shop.models import Product
class Order(models.Model):
    first_name = models.CharField(max_length=50)
    last_name...

Asynchronous tasks

When receiving an HTTP request, you need to return a response to the user as quickly as possible. Remember that in Chapter 7, Tracking User Actions, you used the Django Debug Toolbar to check the time for the different phases of the request/response cycle and the execution time for the SQL queries performed. Every task executed during the course of the request/response cycle adds up to the total response time. Long-running tasks can seriously slow down the server response. How do we return a fast response to the user while still completing time-consuming tasks? We can do it with asynchronous execution.

Working with asynchronous tasks

We can offload work from the request/response cycle by executing certain tasks in the background. For example, a video-sharing platform allows users to upload videos but requires a long time to transcode uploaded videos. When the user uploads a video, the site might return a response informing that the transcoding will start soon and start...

Additional resources

The following resources provide additional information related to the topics covered in this chapter:

• Source code for this chapter – https://github.com/PacktPublishing/Django-5-by-example/tree/main/Chapter08
• Static files for the project – https://github.com/PacktPublishing/Django-5-by-Example/tree/main/Chapter08/myshop/shop/static
• Django session settings – https://docs.djangoproject.com/en/5.0/ref/settings/#sessions
• Django built-in context processors – https://docs.djangoproject.com/en/5.0/ref/templates/api/#built-in-template-context-processors
• Information about RequestContext – https://docs.djangoproject.com/en/5.0/ref/templates/api/#django.template.RequestContext
• Celery documentation – https://docs.celeryq.dev/en/stable/index.html
• Introduction to Celery – https://docs.celeryq.dev/en/stable/getting-started/introduction.html
• Official RabbitMQ Docker image — https://hub.docker.com/_/rabbitmq
• RabbitMQ installation...

Summary

In this chapter, you created a basic e-commerce application. You made a product catalog and built a shopping cart using sessions. You implemented a custom context processor to make the cart available to all templates and created a form for placing orders. You also learned how to implement asynchronous tasks using Celery and RabbitMQ.

In the next chapter, you will discover how to integrate a payment gateway into your shop, add custom actions to the administration site, export data in CSV format, and generate PDF files dynamically.

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Additional resources

The following resources provide additional information related to the topics covered in this chapter:

• Source code for this chapter: https://github.com/PacktPublishing/Django-5-by-example/tree/main/Chapter09
• Stripe website: https://www.stripe.com/
• Stripe Checkout documentation: https://stripe.com/docs/payments/checkout
• Creating a Stripe account: https://dashboard.stripe.com/register
• Stripe account settings: https://dashboard.stripe.com/settings/account
• Stripe Python library: https://github.com/stripe/stripe-python
• Stripe test API keys: https://dashboard.stripe.com/test/apikeys
• Stripe API keys documentation: https://stripe.com/docs/keys
• Stripe API version 2024-04-10 release: https://stripe.com/docs/upgrades#2024-04-10
• Stripe checkout session modes: https://stripe.com/docs/api/checkout/sessions/object#checkout_session_object-mode
• Building absolute URIs with Django: https://docs.djangoproject.com...