Book Image

Web Development with Django Cookbook- Second Edition - Second Edition

By : Aidas Bendoraitis
Book Image

Web Development with Django Cookbook- Second Edition - Second Edition

By: Aidas Bendoraitis

Overview of this book

Django is a web framework that was designed to strike a balance between rapid web development and high performance. It has the capacity to handle applications with high levels of user traffic and interaction, and can integrate with massive databases on the backend, constantly collecting and processing data in real time. Through this book, you'll discover that collecting data from different sources and providing it to others in different formats isn't as difficult as you thought. It follows a task-based approach to guide you through all the web development processes using the Django framework. We’ll start by setting up the virtual environment for a Django project and configuring it. Then you’ll learn to write reusable pieces of code for your models and find out how to manage database schema changes using South migrations. After that, we’ll take you through working with forms and views to enter and list data. With practical examples on using templates and JavaScript together, you will discover how to create the best user experience. In the final chapters, you'll be introduced to some programming and debugging tricks and finally, you will be shown how to test and deploy the project to a remote dedicated server. By the end of this book, you will have a good understanding of the new features added to Django 1.8 and be an expert at web development processes.
Table of Contents (18 chapters)
Web Development with Django Cookbook Second Edition
Credits
About the Author
About the Reviewers
www.PacktPub.com
Preface
Index

Caching the method return value


If you call the same model method with heavy calculations or database queries multiple times in the request-response cycle, the performance of the view might be very slow. In this recipe, you will learn about a pattern that you can use to cache the return value of a method for later repetitive use. Note that we are not using the Django cache framework here, we are just using what Python provides us by default.

Getting ready

Choose an app with a model that has a time-consuming method that will be used repetitively in the same request-response cycle.

How to do it...

This is a pattern that you can use to cache a method return value of a model for repetitive use in views, forms, or templates, as follows:

class SomeModel(models.Model):
    # ...
    def some_expensive_function(self):
        if not hasattr(self, "_expensive_value_cached"):
            # do some heavy calculations...
            # ... and save the result to result variable
            self._expensive_value_cached...