Book Image

Web Development with Django - Second Edition

By : Ben Shaw, Saurabh Badhwar, Chris Guest, Bharath Chandra K S
4.7 (3)
Book Image

Web Development with Django - Second Edition

4.7 (3)
By: Ben Shaw, Saurabh Badhwar, Chris Guest, Bharath Chandra K S

Overview of this book

Do you want to develop reliable and secure applications that stand out from the crowd without spending hours on boilerplate code? You’ve made the right choice trusting the Django framework, and this book will tell you why. 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 will take you through all the essential concepts and help you explore its power to build real-world applications using Python. Throughout the book, you’ll get the grips with the major features of Django 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 presented as exercises and activities, allowing you to challenge yourself in an enjoyable and attainable way. As you advance, you'll acquire 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. You’ll cover everyday tasks that are part of the development cycle of a real-world web application. By the end of this Django book, you'll have the skills and confidence to creatively develop and deploy your own projects.
Table of Contents (19 chapters)

Validating forms and retrieving Python values

So far, we have seen how Django forms make it much simpler to define a form using Python code and have it automatically rendered. We will now look at the other part of what makes Django forms useful: their ability to automatically validate the form and then retrieve native Python objects and values from them.

In Django, a form can either be unbound or bound. These terms describe whether or not the form has had the submitted POST data sent to it for validation. So far, we have only seen unbound forms – they are instantiated without arguments, like this:

form = ExampleForm()

A form is bound if it is called with some data to be used for validation, such as the POST data. A bound form can be created like this:

form = ExampleForm(request.POST)

A bound form allows us to start using built-in validation-related tools on the form instance. First, there’s the is_valid method, which checks the form validity, then the cleaned_data...