Web Development with Django

Learn to build modern web applications with a Python-based framework

Ben Shaw, Saurabh Badhwar, Andrew Bird, Bharath Chandra K S, Chris Guest

• Publisher: Packt Publishing
• Year: 2021
• ISBN:
  9781839213779
• Edition: 1
• Topic: Ciencia de la computación
• Subtopic: Programación en Python

Learn how to create your own websites simply, safely, and quickly with Django by tackling practical activities based on realistic case studies

Key Features

• Understand Django functionality and the Model-View-Template (MVT) paradigm
• Create and iteratively build a book review website, adding features as you build your knowledge
• Explore advanced concepts such as REST API implementation and third-party module integration

Book Description

Do you want to develop reliable and secure applications which stand out from the crowd, rather than spending hours on boilerplate code? Then the Django framework is where you should begin. Often referred to as a 'batteries included' web development framework, Django comes with all the core features needed to build a standalone application.

Web Development with Django takes this philosophy and equips you with the knowledge and confidence to build real-world applications using Python.

Starting with the essential concepts of Django, you'll cover its major features by building a website called Bookr – a repository for book reviews. This end-to-end case study is split into a series of bitesize projects that are presented as exercises and activities, allowing you to challenge yourself in an enjoyable and attainable way.

As you progress, you'll learn various practical skills, including how to serve static files to add CSS, JavaScript, and images to your application, how to implement forms to accept user input, and how to manage sessions to ensure a reliable user experience. Throughout this book, you'll cover key daily tasks that are part of the development cycle of a real-world web application.

By the end of this book, you'll have the skills and confidence to creatively tackle your own ambitious projects with Django.

What you will learn

• Create a new application and add models to describe your data
• Use views and templates to control behavior and appearance
• Implement access control through authentication and permissions
• Develop practical web forms to add features such as file uploads
• Develop a RESTful API and JavaScript code that communicates with it
• Connect to a database such as PostgreSQL

Who this book is for

Web Development with Django is designed for programmers who want to gain web development skills with the Django framework. To fully understand the concepts explained in this book, you must have basic knowledge of Python programming, as well as familiarity with JavaScript, HTML, and CSS.

1. Introduction to Django

Overview

This chapter introduces you to Django and its role in web development. You will begin by learning how the Model View Template (MVT) paradigm works and how Django processes HTTP requests and responses. Equipped with the basic concepts, you'll create your first Django project, called Bookr, an application for adding, viewing, and managing book reviews. It's an application you'll keep enhancing and adding features to throughout this book. You will then learn about the manage.py command (used to orchestrate Django actions). You will use this command to start the Django development server and test whether the code you've written works as expected. You will also learn how to work with PyCharm, a popular Python IDE that you'll be using throughout this book. You will use it to write code that returns a response to your web browser. Finally, you'll learn how to use PyCharm's debugger to troubleshoot problems with your code. By the end of this chapter, you'll have the necessary skills to start creating projects using Django.

Introduction

"The web framework for perfectionists with deadlines." It's a tagline that aptly describes Django, a framework that has been around for over 10 years now. It is battle-tested and widely used, with more and more people using it every day. All this might make you think that Django is old and no longer relevant. On the contrary, its longevity has proved that its Application Programming Interface (API) is reliable and consistent, and even those who learned Django v1.0 in 2007 can mostly write the same code for Django 3 today. Django is still in active development, with bugfixes and security patches being released monthly.

Like Python, the language in which it is written, Django is easy to learn, yet powerful and flexible enough to grow with your needs. It is a "batteries-included" framework, which is to say that you do not have to find and install many other libraries or components to get your application up and running. Other frameworks, such as Flask or Pylons, require manually installing third-party frameworks for database connections or template rendering. Instead, Django has built-in support for database querying, URL mapping, and template rendering (we'll go into detail on what these mean soon). But just because Django is easy to use doesn't mean it is limited. Django is used by many large sites, including Disqus (https://disqus.com/), Instagram (https://www.instagram.com/), Mozilla (https://www.mozilla.org/), Pinterest (https://www.pinterest.com/), Open Stack (https://www.openstack.org/), and National Geographic (http://www.nationalgeographic.com/).

Where does Django fit into the web? When talking about web frameworks, you might think of frontend JavaScript frameworks such as ReactJS, Angular, or Vue. These frameworks are used to enhance or add interactivity to already-generated web pages. Django sits in the layer beneath these tools and instead is responsible for routing a URL, fetching data from databases, rendering templates, and handling form input from users. However, this does not mean you must pick one or the other; JavaScript frameworks can be used to enhance the output from Django, or to interact with a REST API generated by Django.

In this book, we will build a Django project using the methods that professional Django developers use every day. The application is called Bookr, and it allows browsing and adding books and book reviews. This book is divided into four sections. In the first section, we'll start with the basics of scaffolding a Django app and quickly build some pages and serve them with the Django development server. You'll be able to add data to the database using the Django admin site.

The next section focuses on adding enhancements to Bookr. You'll serve static files to add styles and images to the site. By using Django's form library, you'll add interactivity, and by using file uploads, you will be able to upload book covers and other files. You'll then implement user login and learn how to store information about the current user in the session.

In section three, you'll build on your existing knowledge and move to the next level of development. You'll customize the Django admin site and then learn about advanced templating. Next, you'll learn how to build a REST API and generate non-HTML data (such as CSVs and PDFs), and you'll finish the section by learning about testing Django.

Many third-party libraries are available to add functionality to Django and to make development easier and thus save time. In the final section, you'll learn about some of the useful ones and how to integrate them into your application. Applying this knowledge, you'll integrate a JavaScript library to communicate with the REST framework you built in the previous section. Finally, you'll learn how to deploy your Django application to a virtual server.

By the end of the book, you will have enough experience to design and build your own Django project from start to finish.

Scaffolding a Django Project and App

Before diving deep into the theory behind Django paradigms and HTTP requests, we'll show you how easy it is to get a Django project up and running. After this first section and exercise, you will have created a Django project, made a request to it with your browser, and seen the response.

A Django project is a directory that contains all the data for your project: code, settings, templates, and assets. It is created and scaffolded by running the django-admin.py command on the command line with the startproject argument and providing the project name. For example, to create a Django project with the name myproject, the command that is run is this:

django-admin.py startproject myproject

This will create the myproject directory, which Django populates with the necessary files to run the project. Inside the myproject directory are two files (shown in Figure 1.1):

Figure 1.1: Project directory for myproject

manage.py is a Python script that is executed at the command line to interact with your project. We will use it to start the Django dev server, a development web server you will use to interact with your Django project on your local computer. Like django-admin.py, commands are passed in on the command line. Unlike django-admin.py, this script is not mapped in your system path, so we must execute it using Python. We will need to use the command line to do that. For example, inside the project directory, run the following command:

python3 manage.py runserver

This passes the runserver command to the manage.py script, which starts the Django dev server. We will examine more of the commands that manage.py accepts in the Django Project section. When interacting with manage.py in this way, we call these management commands. For example, we might say that we are "executing the runserver management command."

The startproject command also created a directory with the same name as the project, in this case, myproject (Figure 1.1). This is a Python package that contains settings and some other configuration files that your project needs to run. We will examine...