Web Development with Django Cookbook- Second Edition

Web Development with Django Cookbook- Second Edition - Second Edition

By : Aidas Bendoraitis

Buy this Book

Web Development with Django Cookbook- Second Edition - Second Edition

By: Aidas Bendoraitis

Buy this Book

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.

Web Development with Django Cookbook Second Edition

Credits

About the Author

About the Reviewers

www.PacktPub.com

Preface

Free Chapter

Getting Started with Django 1.8

Introduction

Working with a virtual environment

Creating a project file structure

Handling project dependencies with pip

Making your code compatible with both Python 2.7 and Python 3

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

Introduction

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

Using migrations

Switching from South migrations to Django migrations

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

Forms and Views

Introduction

Passing HttpRequest to the form

Utilizing the save method of the form

Uploading images

Creating a form layout with django-crispy-forms

Downloading authorized files

Filtering object lists

Managing paginated lists

Composing class-based views

Generating PDF documents

Implementing a multilingual search with Haystack

Templates and JavaScript

Introduction

Arranging the base.html template

Including JavaScript settings

Using HTML5 data attributes

Opening object details in a modal dialog

Implementing a continuous scroll

Implementing the Like widget

Uploading images by Ajax

Custom Template Filters and Tags

Introduction

Following conventions for your own template filters and tags

Creating a template filter to show how many days have 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

Introduction

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

Django CMS

Introduction

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

Introduction

Creating hierarchical categories

Creating a category administration interface with django-mptt-admin

Creating a category administration interface with django-mptt-tree-editor

Rendering categories in a template

Using a single selection field to choose a category in forms

Using a checkbox list to choose multiple categories in forms

Data Import and Export

Introduction

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 API

Using Django REST framework to create API

Bells and Whistles

Introduction

Using the Django shell

Using database query expressions

Monkey-patching the slugify() function for better internationalization support

Toggling the Debug Toolbar

Using ThreadLocalMiddleware

Caching the method return value

Using Memcached to cache Django views

Using signals to notify administrators about new entries

Checking for missing settings

Testing and Deployment

Introduction

Testing pages with Selenium

Testing views with mock

Testing API created using Django REST framework

Releasing a reusable Django app

Getting detailed error reporting via e-mail

Deploying on Apache with mod_wsgi

Setting up cron jobs for regular tasks

Creating and using the Fabric deployment script

Index

Customer Reviews

5 star

4 star

3 star

2 star

1 star

Creating app configuration

When developing a website with Django, you create one module for the project itself and then, multiple Python modules called applications or apps that combine the different modular functionalities and usually consist of models, views, forms, URL configurations, management commands, migrations, signals, tests, and so on. The Django framework has application registry, where all apps and models are collected and later used for configuration and introspection. Since Django 1.7, meta information about apps can be saved in the AppConfig instance for each used app. Let's create a sample magazine app to take a look at how to use the app configuration there.

Getting ready

Either create your Django app manually or using this command in your virtual environment (learn how to use virtual environments in the Working with a virtual environment recipe), as follows:

(myproject_env)$ django-admin.py startapp magazine

Add some NewsArticle model to models.py, create administration for the model in admin.py, and put "magazine" in INSTALLED_APPS in the settings. If you are not yet familiar with these tasks, study the official Django tutorial at https://docs.djangoproject.com/en/1.8/intro/tutorial01/.

How to do it…

Follow these steps to create and use the app configuration:

First of all, create the apps.py file and put this content in it, as follows:

# magazine/apps.py
# -*- coding: UTF-8 -*-
from __future__ import unicode_literals
from django.apps import AppConfig
from django.utils.translation import ugettext_lazy as _

class MagazineAppConfig(AppConfig):
    name = "magazine"
    verbose_name = _("Magazine")

    def ready(self):
        from . import signals

Then, edit the __init__.py file of the app and put the following content:

# magazine/__init__.py
# -*- coding: UTF-8 -*-
from __future__ import unicode_literals
default_app_config = "magazine.apps.MagazineAppConfig"

Lastly, let's create a signals.py file and add some signal handlers there:

# magazine/signals.py
# -*- coding: UTF-8 -*-
from __future__ import unicode_literals
from django.db.models.signals import post_save, post_delete
from django.dispatch import receiver
from django.conf import settings
from .models import NewsArticle

@receiver(post_save, sender=NewsArticle)
def news_save_handler(sender, **kwargs):
    if settings.DEBUG:
        print("%s saved." % kwargs['instance'])

@receiver(post_delete, sender=NewsArticle)
def news_delete_handler(sender, **kwargs):
    if settings.DEBUG:
        print("%s deleted." % kwargs['instance'])

How it works…

When you run an HTTP server or invoke a management command, django.setup() is called. It loads the settings, sets up logging, and initializes app registry. The app registry is initialized in three steps, as shown in the following:

Django imports the configurations for each item from INSTALLED_APPS in the settings. These items can point to app names or configuration directly, for example,"magazine" or "magazine.apps.NewsAppConfig".
Django tries to import models.py from each app in INSTALLED_APPS and collect all the models.
Finally, Django runs the ready() method for each app configuration. This method is a correct place to register signal handlers, if you have any. The ready() method is optional.
In our example, the MagazineAppConfig class sets the configuration for the magazine app. The name parameter defines the name of the current app. The verbose_name parameter is used in the Django model administration, where models are presented and grouped by apps. The ready() method imports and activates the signal handlers that, when in DEBUG mode, print in the terminal that a NewsArticle was saved or deleted.

There is more…

After calling django.setup(), you can load the app configurations and models from the registry as follows:

>>> from django.apps import apps as django_apps
>>> magazine_app_config = django_apps.get_app_config("magazine")
>>> magazine_app_config
<MagazineAppConfig: magazine>
>>> magazine_app_config.models_module
<module 'magazine.models' from 'magazine/models.pyc'>
NewsArticle = django_apps.get_model("magazine", "NewsArticle")

You can read more about app configuration in the official Django documentation at https://docs.djangoproject.com/en/1.8/ref/applications/

Web Development with Django Cookbook- Second Edition - Second Edition

By : Aidas Bendoraitis

Web Development with Django Cookbook- Second Edition - Second Edition

By: Aidas Bendoraitis

Overview of this book

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Web Development with Django Cookbook- Second Edition - Second Edition

Creating app configuration

Getting ready

How to do it…

How it works…

There is more…

See also