Django (web framework)

Django

The default Django page
Original author(s)	Lawrence Journal-World
Developer(s)	Django Software Foundation
Initial release	July 21, 2005 (2005-07-21)
Stable release	1.4 / March 23, 2012 (2012-03-23)
Development status	active
Written in	Python
Size	6 MB
Type	Web application framework
License	BSD License
Website	djangoproject.com

Django ( /ˈdʒæŋɡoʊ/ JANG-goh) is an open source web application framework, written in Python, which follows the model-view-controller architectural pattern. It was originally developed to manage several news-oriented sites for The World Company of Lawrence, Kansas, and was released publicly under a BSD license in July 2005; the framework was named after guitarist Django Reinhardt. In June 2008 it was announced that a newly formed Django Software Foundation will maintain Django in the future.

Django's primary goal is to ease the creation of complex, database-driven websites. Django emphasizes reusability and "pluggability" of components, rapid development, and the principle of don't repeat yourself. Python is used throughout, even for settings, files, and data models.

Django also provides an optional administrative create, read, update and delete interface that is generated dynamically through introspection and configured via admin models.

Components

Screenshot of the Django admin interface for modifying a user.

The core Django MVC framework consists of an object-relational mapper which mediates between data models (defined as Python classes) and a relational database ("Model"); a system for processing requests with a web templating system ("View") and a regular-expression-based URL dispatcher ("Controller").

Also included in the core framework are:

• A lightweight, standalone web server for development and testing.
• A form serialization and validation system which can translate between HTML forms and values suitable for storage in the database.
• A caching framework which can use any of several cache methods.
• Support for middleware classes which can intervene at various stages of request processing and carry out custom functions.
• An internal dispatcher system which allows components of an application to communicate events to each other via pre-defined signals.
• An internationalization system, including translations of Django's own components into a variety of languages.
• A serialization system which can produce and read XML and/or JSON representations of Django model instances.
• A system for extending the capabilities of the template engine.
• An interface to Python's built-in unit test framework.

Bundled applications

The main Django distribution also bundles a number of applications in its "contrib" package, including:

• An extensible authentication system.
• The dynamic administrative interface.
• Tools for generating RSS and Atom syndication feeds.
• A flexible commenting system.
• A sites framework that allows one Django installation to run multiple websites, each with their own content and applications.
• Tools for generating Google Sitemaps.
• Tools for preventing cross-site request forgery.
• Template libraries which enable the use of lightweight markup languages such as Textile and Markdown.
• A framework for creating GIS applications.

Applications built on Django

• django CMS, a free and open source content management system platform for publishing content on the World Wide Web and intranets, and written in Python.
• Armstrong CMS for news blogging by large organizations.
• Greendizer for a cloud invoicing platform.
• The Pinax framework provides reusable applications aimed at Django-based social networking websites.
• RapidSMS is a framework for SMS applications built on Django.
• Pootle is an online translation management tool.
• Review Board is a web-based code review tool.
• Rietveld is another web-based code review tool built on Django. It was originally written to serve as a showcase for using Django with Google App Engine.
• Disqus uses Django for an online discussion platform.
• Firstpex uses Django to run an auction style site for startups and companies selling shares and looking for investment.
• Spotify uses Django for some of their web sites.
• Instagram uses Django for their web application
• Yandex uses Django for their weather forecast site, OpenID provider, blog hosting service, internal Wiki and internal Mail Archives.
• Transifex – an open source platform for localization.
• Bucketlist – uses Django to let users store life goals.
• The Public Broadcasting Service in the United States uses Django for some of their web sites.
• The Berkeley Graduate School of Journalism uses Django for their websites.
• The Faculty of Electrical Engineering and Information Sciences at the Ruhr University Bochum uses Django for their website.
• Universal Subtitles uses Django for its free and open source collaborative subtitling site.
• FreeNAS uses Django for its web interface in its 8.0 major release.
• DjangoSites.org uses Django for handling its Django-powered sites directory.
• Ion Torrent provides a Django-based web interface with their genome sequencers for viewing and organizing experimental and sequencing data
• PBS's Merlin, a platform for managing member stations' video metadata, is built on Django.
• Whiskey Media websites, including Giant Bomb, are built on Django.
• Fitocracy, a social network and fitness game is built on Django
• the European Centre for Medium-Range Weather Forecasts, uses Django for some of their web services

Server arrangements

Django can be run in conjunction with Apache using mod_wsgi or mod_python. Django can run nicely with Cherokee using flup (a Python module). Django also includes the ability to launch a FastCGI server, enabling use behind any web server which supports FastCGI, such as Lighttpd, Hiawatha. Another deployment option is nginx and uwsgi. It should also be possible to use other WSGI-compliant web servers. Django officially supports four database backends: PostgreSQL, MySQL, SQLite, and Oracle. MS SQL backend can be used with django-mssql but only in Microsoft operating systems, similarly external backends exist for IBM DB2, SQL Anywhere and Firebird. There is a fork named django-nonrel which supports NoSQL databases like MongoDB and Google App Engine's Datastore.

Django may also be run in conjunction with Jython on any Java EE application server such as GlassFish or JBoss. In this case django-jython must be installed in order to provide JDBC drivers for database connectivity, which also provides functionality to compile Django in to a .war suitable for deployment.

Versions of Django prior to 1.0 had multithreading issues. If you are using such a version, possibly you should use it in a single-threaded server configuration, such as with Apache prefork MPM using mod_python, or the embedded mode of mod_wsgi. Although Django 1.0 is principally believed to now be thread safe, some minor threading issues are still occasionally being found; it may be prudent to continue to use a single-threaded server configuration and/or stay current with Django releases and notices about the multithreading issues.

Google App Engine includes support for Django version 1.x.x as one of the bundled frameworks.

Integrated development environments

While a number of Django developers use text editors such as Vim, Emacs or TextMate with Django Bundle for their projects, others prefer more specialized tools providing debugging, refactoring, unit testing, etc.

• Komodo IDE
• Eclipse with PyDev
• PyCharm
• NetBeans with Django Plugin
• Wing IDE
• Eric Python IDE

DjangoCon

There is a twice-yearly conference for Django developers and users, named "DjangoCon", that has been held since September 2008. One DjangoCon a year is held in Europe, in May or June; while the other is held in the United States in September, usually in Portland, Oregon.

Books

• The Definitive Guide to Django (Apress) - first edition December 2007, second edition July 2009. Released under the GNU Free Documentation License. Available online for free at www.djangobook.com.
• Practical Django Projects by James Bennett (Apress) - first edition June 2008, second edition June 2009.
• Pro Django by Marty Alchin (Apress) - December 2008.
• Python Web Development with Django by Jeff Forcier, Wesley Chun, and Paul Bissex (Addison-Wesley) - November 2008.

See also

• Comparison of web application frameworks

Bibliography

• Alchin, Marty (December 16, 2008), Pro Django (1st ed.), Apress, p. 320, ISBN 1430210478, http://www.apress.com/book/view/1430210478 
• Forcier, Jeff; Bissex, Paul; Chun, Wesley (November 3, 2008), Python Web Development with Django (1st ed.), Addison-Wesley, p. 408, ISBN 0132356139, OCLC 213835556, http://www.informit.com/store/product.aspx?isbn=0132356139 
• Bennett, James (June 24, 2009), Practical Django Projects (2nd ed.), Apress, p. 272, ISBN 1430219386, http://www.apress.com/book/view/1430219386 
• Holovaty, Adrian; Kaplan-Moss, Jacob (July 8, 2009), The Definitive Guide to Django: Web Development Done Right (2nd ed.), Apress, p. 536, ISBN 143021936X, http://www.apress.com/book/view/143021936X 
• McGaw, Jim (October 29, 2009), Beginning Django E-Commerce (1st ed.), Apress, p. 300, ISBN 1430225351, http://www.apress.com/book/view/1430225351 

External links

• Django Project home page
• How to run Django on Lighttpd with FastCGI
• Popularity of the python-django package
• The trade character of Django