Introduction to Django, given at an Auckland NZPUG meeting in June 2008.

1. Django 101
Robert Coup
http://rob.coup.net.nz/

2. What is Django?
“ The Web framework for perfectionists
with deadlines
Django makes it easier to build better Web
apps more quickly and with less code
www.djangoproject.com

3. Who am I?
• Robert Coup
• CTO of Koordinates
- making geospatial data more accessible
- http://koordinates.com
• OSS contributor
• 2 year Djangonaut
• robert@coup.net.nz

4. What’s it for?
• Building dynamic Web sites
• A high level Web framework
• Abstracts common problems
• Shortcuts for fast development

5. Key Features
• nice url handling
• object : db mapping
• forms
• templating
• admin interface
• caching, syndication, middleware, email, sql, modules, authentication, sessions,
comments, sitemaps, gis, …

6. So? And?
• work at a nice abstraction level
• just Python, no magic
• gets out of your way

7. Architecture
• “MVT”
• Models describe your data
• Views control what a user sees and does
• Templates are what they see

8. Sample App - Yachties
• Yacht racing crews
• Schedule of races
• Notify and Invite crew to races
• Know who’s coming

9. Install Django
• Database: Sqlite, Postgres, MySQL, Oracle
• Web: Apache, FastCGI, wsgi, dev-server
• Use Trunk, checkout from SVN
• www.djangoproject.com/download
• python setup.py install

10. Projects and Apps
• django-admin startproject yachties
• cd yachties
• django-admin startapp racing

11. Models
• models.py
• describes the fields
• turned into database tables
• the logic and rules of the application

12. Settings
• settings.py
• Just a Python file

13. Databases
• Django will create your tables for you
• python manage.py syncdb
• Additional SQL commands:
• python manage.py sql*
• Ability to preload data

14. Shell
• python manage.py shell
• from yachties.racing.models import
Race
• Manipulate your models live

15. Server
• Server for development & debugging
• python manage.py runserver
• http://localhost:8000/

16. Automatic Admin Site
• Built dynamically from your models
• Authentication & validation
• Flexible and customisable

17. URL Handling
• All in urls.py
• Separates views from how they’re called
• Just regular expressions

18. Views
• The “controller”
• Just Python functions
• that take a request
• and return a response

19. Templates
• What the user sees
• No code

20. Templates
• Pulls data from a dictionary (“context”)
• Simple logic constructs (“tags”)
• Simple data manipulation (“filters”)
• Inheritance

21. More
• Form generation & handling
• Contrib apps:
• builtin: admin, forms, gis, feeds,
• 3 party: see Google Code
rd
• Any Python code will work with Django

22. Support
• Quality documentation
• Django Book www.djangobook.com
• www.djangosnippets.org
• Mailing lists, IRC

23. Google App Engine
• Google’s “cloud computing” platform
• Python based
• Runs Django
• Modified model layer
• http://code.google.com/appengine/

24. Sites
• Lots of news/journalism sites
• Washington Post
• Pownce
• Koordinates
• www.djangosites.org

25. Questions?