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

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 or local_settings.py file. This is useful especially for reusable apps.

Getting ready

Either create your Django app manually or using the following command:

(myproject_env)$ django-admin.py startapp myapp1

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:

# models.py or app_settings.py
# -*- coding: UTF-8 -*-
from __future__ import unicode_literals
from django.conf import settings
from django.utils.translation import ugettext_lazy as _

SETTING1 = getattr(settings, "MYAPP1_SETTING1", u"default value")
MEANING_OF_LIFE = getattr(settings, "MYAPP1_MEANING_OF_LIFE", 42)
STATUS_CHOICES = getattr(settings, "MYAPP1_STATUS_CHOICES", (
    ("draft", _("Draft")),
    ("published", _("Published")),
    ("not_listed", _("Not Listed")),
))

Then, you can use the app settings in models.py, as follows:

# models.py
# -*- coding: UTF-8 -*-
from __future__ import unicode_literals
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 just one project, you simply open settings.py and add the following:

# settings.py
# …
from django.utils.translation import ugettext_lazy as _
MYAPP1_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 module, and if they are not found, the default values are assigned.