Book Image

Django Design Patterns and Best Practices - Second Edition

By : Arun Ravindran
Book Image

Django Design Patterns and Best Practices - Second Edition

By: Arun Ravindran

Overview of this book

Building secure and maintainable web applications requires comprehensive knowledge. The second edition of this book not only sheds light on Django, but also encapsulates years of experience in the form of design patterns and best practices. Rather than sticking to GoF design patterns, the book looks at higher-level patterns. Using the latest version of Django and Python, you’ll learn about Channels and asyncio while building a solid conceptual background. The book compares design choices to help you make everyday decisions faster in a rapidly changing environment. You’ll first learn about various architectural patterns, many of which are used to build Django. You’ll start with building a fun superhero project by gathering the requirements, creating mockups, and setting up the project. Through project-guided examples, you’ll explore the Model, View, templates, workflows, and code reusability techniques. In addition to this, you’ll learn practical Python coding techniques in Django that’ll enable you to tackle problems related to complex topics such as legacy coding, data modeling, and code reusability. You’ll discover API design principles and best practices, and understand the need for asynchronous workflows. During this journey, you’ll study popular Python code testing techniques in Django, various web security threats and their countermeasures, and the monitoring and performance of your application.
Table of Contents (21 chapters)
Title Page
Copyright and Credits
PacktPub.com
Contributors
Preface
Index

How forms work


Forms can be tricky to understand because interacting with them takes more than one request-response cycle. In the simplest scenario, you need to present an empty form, which the user then fills in correctly and submits. Conversely, they might enter some invalid data, in which case the form needs to be resubmitted until the entire form is valid.

From this scenario, we can see that a form can be one of several states, changing between them:

  • Empty form (unfilled form): This form is called an unbound form in Django
  • Filled form: This form is called a bound form in Django
  • Submitted form with errors: This form is called a bound form but not a valid form
  • Submitted form without errors: This form is called a bound and valid form

Note

The users will never see the form in the submitted form without errors state. They don't have to. Typically, submitting a valid form should take the users to a success page.

Forms in Django

Django's form class instances contain the state of each field and, by...