Book Image

Django 2 Web Development Cookbook - Third Edition

By : Jake Kronika, Aidas Bendoraitis

Book Image

Django 2 Web Development Cookbook - Third Edition

By: Jake Kronika, Aidas Bendoraitis

Overview of this book

Django is a framework designed to balance rapid web development with high performance. It handles high levels of user traffic and interaction, integrates with a variety of databases, and collects and processes data in real time. This book follows a task-based approach to guide you through developing with the Django 2.1 framework, starting with setting up and configuring Docker containers and a virtual environment for your project. You'll learn how to write reusable pieces of code for your models and manage database changes. You'll work with forms and views to enter and list data, applying practical examples using templates and JavaScript together for the optimum user experience. This cookbook helps you to adjust the built-in Django administration to fit your needs and sharpen security and performance to make your web applications as robust, scalable, and dependable as possible. You'll also explore integration with Django CMS, the popular content management suite. In the final chapters, you'll learn programming and debugging tricks and discover how collecting data from different sources and providing it to others in various formats can be a breeze. By the end of the book, you'll learn how to test and deploy projects to a remote dedicated server and scale your application to meet user demands.

Preface

Who this book is for

What this book covers

To get the most out of this book

Free Chapter

Getting Started with Django 2.1

Getting Started with Django 2.1

Working with a virtual environment

Creating a virtual environment project file structure

Working with Docker

Creating a Docker project file structure

Handling project dependencies with pip

Including external dependencies in your project

Configuring settings for development, testing, staging, and production environments

Defining relative paths in the settings

Creating and including local settings

Setting up STATIC_URL dynamically for Subversion users

Setting up STATIC_URL dynamically for Git users

Setting UTF-8 as the default encoding for MySQL configuration

Setting the Subversion ignore property

Creating the Git ignore file

Deleting Python-compiled files

Respecting the import order in Python files

Creating app configuration

Defining overwritable app settings

Database Structure and Modeling

Database Structure and Modeling

Using model mixins

Creating a model mixin with URL-related methods

Creating a model mixin to handle creation and modification dates

Creating a model mixin to take care of meta tags

Creating a model mixin to handle generic relations

Handling multilingual fields

Enabling schema microdata enhancements

Using migrations

Switching from South migrations to Django migrations

Changing a foreign key to the many-to-many field

Forms and Views

Forms and Views

Passing HttpRequest to a form

Utilizing the save method of the form

Uploading images

Creating a form layout with custom templates

Creating a form layout with django-crispy-forms

Filtering object lists

Managing paginated lists

Composing class-based views

Generating PDF documents

Implementing a multilingual search with Haystack and Whoosh

Templates and JavaScript

Templates and JavaScript

Exposing settings in JavaScript

Arranging the base.html template

Using HTML5 data attributes

Providing responsive images

Opening object details in a modal dialog

Implementing a continuous scroll

Implementing the Like widget

Uploading images via Ajax

Customizing Template Filters and Tags

Customizing Template Filters and Tags

Following conventions for your own template filters and tags

Creating a template filter to show how much time has passed since a post was published

Creating a template filter to extract the first media object

Creating a template filter to humanize URLs

Creating a template tag to include a template if it exists

Creating a template tag to load a QuerySet in a template

Creating a template tag to parse content as a template

Creating a template tag to modify request query parameters

Model Administration

Model Administration

Customizing columns on the change list page

Creating admin actions

Developing change list filters

Customizing default admin settings

Inserting a map into a change form

Security and Performance

Security and Performance

Making forms secure from Cross Site Request Forgery (CSRF)

Implementing password validation

Downloading authorized files

Adding a dynamic watermark to images

Authenticating with Auth0

Caching the method return value

Using Memcached to cache Django views

Using Redis to cache Django views

Django CMS

Creating templates for Django CMS

Structuring the page menu

Converting an app to a CMS app

Attaching your own navigation

Writing your own CMS plugin

Adding new fields to the CMS page

Hierarchical Structures

Hierarchical Structures

Creating hierarchical categories with django-mptt

Creating a category administration interface with django-mptt-admin

Rendering categories in a template with django-mptt

Using a single selection field to choose a category in forms with django-mptt

Using a checkbox list to choose multiple categories in forms with django-mptt

Creating hierarchical categories with django-treebeard

Creating a basic category administration interface with django-treebeard

Importing and Exporting Data

Importing and Exporting Data

Importing data from a local CSV file

Importing data from a local Excel file

Importing data from an external JSON file

Importing data from an external XML file

Creating filterable RSS feeds

Using Tastypie to create an API

Using Django REST framework to create an API

Bells and Whistles

Bells and Whistles

Using the Django shell

Using database query expressions

Monkey patching the slugify() function for better internationalization support

Toggling the Debug Toolbar

Using ThreadLocalMiddleware

Using signals to notify administrators about new entries

Checking for missing settings

Testing and Deployment

Testing and Deployment

Testing views with mock

Testing APIs created using the Django REST framework

Releasing a reusable Django app

Getting detailed error reporting via email

Deploying on Apache with mod_wsgi

Setting up cron jobs for regular tasks

Other Books You May Enjoy

Other Books You May Enjoy

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Defining overwritable app settings

This recipe will show you how to define settings for your app that can be then overwritten in your project's settings.py file. This is useful especially for reusable apps.

Getting ready

Follow the steps for Getting ready in the Creating app configuration recipe to create your Django app.

How to do it...

If you just have one or two settings, you can use the following pattern in your models.py file. If the settings are extensive and you want to have them organized better, create an app_settings.py file in the app and put the settings in the following way:

# magazine/models.py or magazine/app_settings.py
from django.conf import settings
from django.utils.translation import ugettext_lazy as _
 
SETTING1 = getattr(settings, "MAGAZINE_SETTING1", "default value")
MEANING_OF_LIFE = getattr(settings, "MAGAZINE_MEANING_OF_LIFE", 42)
STATUS_CHOICES = getattr(settings, "MAGAZINE_STATUS_CHOICES", (
    ("draft", _("Draft")),
    ("published", _("Published")),
    ("not_listed", _("Not Listed")),
))

If the settings were defined in an app_settings.py file, then you can import and use them in models.py, as follows:

# magazine/models.py
from django.db import models
from django.utils.translation import ugettext_lazy as _

from .app_settings import STATUS_CHOICES


class NewsArticle(models.Model):
    # ...
    status = models.CharField(_("Status"),
                              max_length=20,
                              choices=STATUS_CHOICES)

If you want to overwrite the STATUS_CHOICES setting for a given project, you simply open settings.py for that project and add the following:

# settings.py
from django.utils.translation import ugettext_lazy as _

# ...

MAGAZINE_STATUS_CHOICES = (
    ("imported", _("Imported")),
    ("draft", _("Draft")),
    ("published", _("Published")),
    ("not_listed", _("Not Listed")),
    ("expired", _("Expired")),
)

How it works...

The getattr(object, attribute_name[, default_value]) Python function tries to get the attribute_name attribute from object and returns default_value if it is not found. In this case, different settings are tried in order to be taken from the Django project settings.py module or, if they are not found, the default values are assigned.