Book Image

Web Development with Django

By : Ben Shaw, Saurabh Badhwar, Andrew Bird, Bharath Chandra K S, Chris Guest
Book Image

Web Development with Django

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

Overview of this book

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.

Related Content you might be interested in

Current Title:

Small book image
Web Development with Django
Ben Shaw | Saurabh Badhwar | Andrew Bird | Bharath Chandra K S | Chris Guest
Feb, 2021 | 826 pages
No titles found
Table of Contents (17 chapters)
Preface
About the Book
1
1. Introduction to Django
1. Introduction to Django
Introduction
Scaffolding a Django Project and App
Model View Template
Summary
Free Chapter
2
2. Models and Migrations
2. Models and Migrations
Introduction
Databases
SQL CRUD Operations
Relationships
Many to Many
Django's Database CRUD Operations
Summary
3
3. URL Mapping, Views, and Templates
3. URL Mapping, Views, and Templates
Introduction
Function-Based Views
Class-Based Views
URL Configuration
Templates
Django Template Language
Summary
4
4. Introduction to Django Admin
4. Introduction to Django Admin
Introduction
Creating a Superuser Account
CRUD Operations Using the Django Admin App
Registering the Reviews Model
Customizing the Admin Interface
Summary
5
5. Serving Static Files
5. Serving Static Files
Introduction
Static File Serving
Summary
6
6. Forms
6. Forms
Introduction
What Is a Form?
The Django Forms Library
Validating Forms and Retrieving Python Values
Summary
7
7. Advanced Form Validation and Model Forms
7. Advanced Form Validation and Model Forms
Introduction
Custom Field Validation and Cleaning
Summary
8
8. Media Serving and File Uploads
8. Media Serving and File Uploads
Introduction
Settings for Media Uploads and Serving
Context Processors and Using MEDIA_URL in Templates
File Uploads Using HTML Forms
Storing Files on Model Instances
Summary
9
9. Sessions and Authentication
9. Sessions and Authentication
Introduction
Middleware
Sessions
Summary
10
10. Advanced Django Admin and Customizations
10. Advanced Django Admin and Customizations
Introduction
Customizing the Admin Site
Adding Views to the Admin Site
Summary
11
11. Advanced Templating and Class-Based Views
11. Advanced Templating and Class-Based Views
Introduction
Template Filters
Custom Template Filters
Template Tags
Django Views
Class-Based Views
Summary
12
12. Building a REST API
12. Building a REST API
Introduction
REST APIs
Serializers
ViewSets
Routers
Authentication
Summary
13
13. Generating CSV, PDF, and Other Binary Files
13. Generating CSV, PDF, and Other Binary Files
Introduction
Working with Python's CSV Module
Working with Excel Files in Python
Working with PDF Files in Python
Playing with Graphs in Python
Integrating Visualizations with Django
Summary
14
14. Testing
14. Testing
Introduction
The Importance of Testing
Automation Testing
Testing in Django
Testing Django Models
Testing Django Views
Django Request Factory
Test Case Classes in Django
Summary
15
15. Django Third-Party Libraries
15. Django Third-Party Libraries
Introduction
django-crispy-forms
Summary
16
16. Using a Frontend JavaScript Library with Django
16. Using a Frontend JavaScript Library with Django
Introduction
JavaScript Frameworks
JavaScript Introduction
Summary

Databases

A database is a structured collection of data that helps manage information easily. A software layer called the Database Management System (DBMS) is used to store, maintain, and perform operations on the data. Databases are of two types, relational databases and non-relational databases.

Relational Databases

Relational databases or Structured Query Language (SQL) databases store data in a pre-determined structure of rows and columns called tables. A database can be made up of more than one such table, and these tables have a fixed structure of attributes, data types, and relations with other tables. For example, as we just saw in Figure 2.1, the book inventory table has a fixed structure of columns comprising Book Number, Author, Title, and Number of Copies, and the entries form the rows in the table. There could be other tables as well, such as Student Information and Lending Records, which could be related to the inventory table. Also, whenever a book is lent to a student, the records will be stored per the relationships between multiple tables (say, the Student Information and the Book Inventory tables).

This pre-determined structure of rules defining the data types, tabular structures, and relationships across different tables acts like scaffolding or a blueprint for a database. This blueprint is collectively called a database schema. When applied to a database, it will prepare the database to store application data. To manage and maintain these databases, there is a common language for relational databases called SQL. Some examples of relational databases are SQLite, PostgreSQL, MySQL, and OracleDB.

Non-Relational Databases

Non-relational databases or NoSQL (Not Only SQL) databases are designed to store unstructured data. They are well suited to large amounts of generated data that does not follow rigid rules, as is the case with relational databases. Some examples of non-relational databases are Cassandra, MongoDB, CouchDB, and Redis.

For example, imagine that you need to store the stock value of companies in a database using Redis. Here, the company name will be stored as the key and the stock value as the value. Using the key-value type NoSQL database in this use case is appropriate because it stores the desired value for a unique key and is faster to access.

For the scope of this book, we will be dealing only with relational databases as Django does not officially support non-relational databases. However, if you wish to explore, there are many forked projects, such as Django non-rel, that support NoSQL databases.

Database Operations Using SQL

SQL uses a set of commands to perform a variety of database operations, such as creating an entry, reading values, updating an entry, and deleting an entry. These operations are collectively called CRUD operations, which stands for Create, Read, Update, and Delete. To understand database operations in detail, let's first get some hands-on experience with SQL commands. Most relational databases share a similar SQL syntax; however, some operations will differ.

For the scope of this chapter, we will use SQLite as the database. SQLite is a lightweight relational database that is a part of Python standard libraries. That's why Django uses SQLite as its default database configuration. However, we will also learn more about how to perform configuration changes to use other databases in Chapter 17, Deployment of a Django Application (Part 1 – Server Setup). This chapter can be downloaded from the GitHub repository of this book, from http://packt.live/2Kx6FmR.

Data Types in Relational databases

Databases provide us with a way to restrict the type of data that can be stored in a given column. These are called data types. Some examples of data types for a relational database such as SQLite3 are given here:

  • INTEGER is used for storing integers.
  • TEXT can store text.
  • REAL is used for floating-point values.

For example, you would want the title of a book to have TEXT as the data type. So, the database will enforce a rule that no type of data, other than text data, can be stored in that column. Similarly, the book's price can have a REAL data type, and so on.

Exercise 2.01: Creating a Book Database

In this exercise, you will create a book database for a book review application. For better visualization of the data in the SQLite database, you will install an open-source tool called DB Browser for SQLite. This tool helps visualize the data and provides a shell to execute the SQL commands.

If you haven't done so already, visit the URL https://sqlitebrowser.org and from the downloads section, install the application as per your operating system and launch it. Detailed instructions for DB Browser installation can be found in the Preface.

Note

Database operations can be performed using a command-line shell as well.

  1. After launching the application, create a new database by clicking New Database in the top-left corner of the application. Create a database named bookr, as you are working on a book review application:
    Figure 2.2: Creating a database named bookr

    Figure 2.2: Creating a database named bookr

  2. Next, click the Create Table button in the top-left corner and enter book as the table name.

    Note

    After clicking the Save button, you may find that the window for creating a table opens up automatically. In that case, you won't have to click the Create Table button; simply proceed with the creation of the book table as specified in the preceding step.

  3. Now, click the Add field button, enter the field name as title, and select the type as TEXT from the dropdown. Here TEXT is the data type for the title field in the database:
    Figure 2.3: Adding a TEXT field named title

    Figure 2.3: Adding a TEXT field named title

  4. Similarly, add two more fields for the table named publisher and author and select TEXT as the type for both the fields. Then, click the OK button:
    Figure 2.4: Creating TEXT fields named publisher and author

Figure 2.4: Creating TEXT fields named publisher and author

This creates a database table called book in the bookr database with the fields title, publisher, and author. This can be seen as follows:

Figure 2.5: Database with the fields title, publisher, and author

Figure 2.5: Database with the fields title, publisher, and author

In this exercise, we used an open-source tool called DB Browser (SQLite) to create our first database called bookr, and in it, we created our first table named book.

Previous Section
End of Section 3
Next Section