Agile Web Development with Django October 1st, 2009 South Coast Linux User Group Joshua Partogi http://scrum8.com http://twitter.com/scrum8

About Me Java programmer by profession Web developer hobbyist

Java programmer by profession

Web developer hobbyist

How I got here 1) I want to have an online web that I can play with during my freetime 2) I want to deploy my webapp/website on a cheap VPS 3) Java is too expensive to deploy on standard VPS plan 4) PHP is just so messy for long term development 5) Ruby on Rails is good but it's on steroids

1) I want to have an online web that I can play with during my freetime

2) I want to deploy my webapp/website on a cheap VPS

3) Java is too expensive to deploy on standard VPS plan

4) PHP is just so messy for long term development

5) Ruby on Rails is good but it's on steroids

What is django? It is a web framework for perfectionists with deadline It came out of online publishing world in Lawrence, Kansas For that reason, it gain popularity (mostly) in journalism world It is made with python, a really clean multi-paradigm dynamic language

It is a web framework for perfectionists with deadline

It came out of online publishing world in Lawrence, Kansas

For that reason, it gain popularity (mostly) in journalism world

It is made with python, a really clean multi-paradigm dynamic language

An opiniated (but flexible) web framework for online publishing system that gears web developers towards fast-moving changes

An opiniated (but flexible) web framework for online publishing system that gears web developers towards fast-moving changes

Opiniated framework is good. If your have the same opinions about how a framework should be, you will most likely like that framework django is opiniated towards online newspaper site

Why django? 1) Comprehensive documentation Everybody on the net just praise about it 2) No rocket science, really simple 3) Many built-in features Mainly the admin system 4) Reusable software concept Plug and play one application accross many other django projects Build many small applications, not monolithic gigantic applications

1) Comprehensive documentation

Everybody on the net just praise about it

2) No rocket science, really simple

3) Many built-in features

Mainly the admin system

4) Reusable software concept

Plug and play one application accross many other django projects

Build many small applications, not monolithic gigantic applications

Get django 1) sudo python setup.py install 2) The bleeding edge version: http://code.djangoproject.com/svn/django/trunk/

1) sudo python setup.py install

2) The bleeding edge version:

http://code.djangoproject.com/svn/django/trunk/

Let's see some code!

Create django project django-admin.py startproject myblog

django-admin.py startproject myblog

Create django app python manage.py startapp blog

python manage.py startapp blog

Install django app settings.py INSTALLED_APPS = ( 'django.contrib.admin', 'myblog.blog', )

settings.py

INSTALLED_APPS = (

'django.contrib.admin',

'myblog.blog',

)

Modify DB config settings.py DATABASE_ENGINE = 'sqlite3' DATABASE_NAME = 'myblog' DATABASE_USER = '' DATABASE_PASSWORD = ''

settings.py

DATABASE_ENGINE = 'sqlite3'

DATABASE_NAME = 'myblog'

DATABASE_USER = ''

DATABASE_PASSWORD = ''

Create model models.py from django.db import models from django.contrib.auth.models import User class Entry(models.Model): title = models.CharField(max_length=128) content = models.TextField() slug = models.SlugField(max_length=128) created = models.DateTimeField(auto_now_add=True) def get_absolute_url(self): return "/%s/%s/" % (self.created.strftime("%Y/%m/%d"), self.slug)

models.py

from django.db import models

from django.contrib.auth.models import User

class Entry(models.Model):

title = models.CharField(max_length=128)

content = models.TextField()

slug = models.SlugField(max_length=128)

created = models.DateTimeField(auto_now_add=True)

def get_absolute_url(self):

return "/%s/%s/" % (self.created.strftime("%Y/%m/%d"), self.slug)

Generate tables python manage.py syncdb

python manage.py syncdb

Activate admin urls.py from django.contrib import admin admin.autodiscover urlpatterns = patterns('', (r'^admin/', include(admin.site.urls)), )

urls.py

from django.contrib import admin

admin.autodiscover

urlpatterns = patterns('',

(r'^admin/', include(admin.site.urls)),

)

Create admin admin.py from django.contrib import admin from myblog.blog.models import Entry class EntryAdmin(admin.ModelAdmin): date_hierarchy = 'created' list_filter = ('created',) list_display = ('title', 'created') admin.site.register(Entry, EntryAdmin)

admin.py

from django.contrib import admin

from myblog.blog.models import Entry

class EntryAdmin(admin.ModelAdmin):

date_hierarchy = 'created'

list_filter = ('created',)

list_display = ('title', 'created')

admin.site.register(Entry, EntryAdmin)

Design URL urls.py urlpatterns = patterns('', (r'^$', 'myblog.blog.views.list'), )

urls.py

urlpatterns = patterns('',

(r'^$', 'myblog.blog.views.list'),

)

Create views views.py from django.template import RequestContext from django.shortcuts import render_to_response from myblog.blog.models import Entry def list(request): entries = Entry.objects.all() return render_to_response('blog/list.html',{ 'entries': entries, 'request': request }, context_instance=RequestContext(request))

views.py

from django.template import RequestContext

from django.shortcuts import render_to_response

from myblog.blog.models import Entry

def list(request):

entries = Entry.objects.all()

return render_to_response('blog/list.html',{

'entries': entries,

'request': request

}, context_instance=RequestContext(request))

Set template directory settings.py import os ROOT_PATH = os.path.realpath(os.path.dirname(__file__)) TEMPLATE_DIRS = ( os.path.join(ROOT_PATH, 'templates'), )

settings.py

import os

ROOT_PATH = os.path.realpath(os.path.dirname(__file__))

TEMPLATE_DIRS = (

os.path.join(ROOT_PATH, 'templates'),

)

Create templates In templates/blog/list.html {% for entry in entries %} <div><a href=&quot;{{ entry.get_absolute_url }}&quot;> {{ entry.title }}</a> posted on: {{ entry.created|date:&quot;D d M Y&quot; }} </div> <div>{{ entry.content }}</div> {% endfor %}

In templates/blog/list.html

{% for entry in entries %}

<div><a href=&quot;{{ entry.get_absolute_url }}&quot;>

{{ entry.title }}</a>

posted on: {{ entry.created|date:&quot;D d M Y&quot; }}

</div>

<div>{{ entry.content }}</div>

{% endfor %}

MTV Concept Models domain spesific representation of the data on which the application operates Template how the data that is delegated from the view is presented Views describes the data that gets presented to the user (which data is presented)

Models

domain spesific representation of the data on which the application operates

Template

how the data that is delegated from the view is presented

Views

describes the data that gets presented to the user (which data is presented)

Deployment 1) Dynamic processing a) mod_python b) mod_wsgi c) fastcgi 2) Static pages a) Apache b) lighttpd c) nginx

1) Dynamic processing

a) mod_python

b) mod_wsgi

c) fastcgi

2) Static pages

a) Apache

b) lighttpd

c) nginx

Database support 1) MySQL 2) Postgresql 3) SQLite 4) Oracle 5) SQL Server http://code.google.com/p/django-mssql/ 6) IBM DB2 http://code.google.com/p/ibm-db/

1) MySQL

2) Postgresql

3) SQLite

4) Oracle

5) SQL Server http://code.google.com/p/django-mssql/

6) IBM DB2 http://code.google.com/p/ibm-db/

Other cool stuff 1) commenting system 2) feeds system 3) generic view

1) commenting system

2) feeds system

3) generic view

Pre-made django project Pinax Project: Content Management System http://pinaxproject.com/ Satchmo Project: Online cart system http://satchmoproject.com

Pinax Project: Content Management System

http://pinaxproject.com/

Satchmo Project: Online cart system

http://satchmoproject.com

Sites using it http://www.washingtontimes.com/ http://www.torontolife.com/ http://bitbucket.org/ http://www.tabblo.com/

http://www.washingtontimes.com/

http://www.torontolife.com/

http://bitbucket.org/

http://www.tabblo.com/

My django apps Online site http://scrum8.com Simple weblog http://blog.scrum8.com Free listing job board http://jobs.scrum8.com Other stuffs http://github.com/scrum8

Online site

http://scrum8.com

Simple weblog

http://blog.scrum8.com

Free listing job board

http://jobs.scrum8.com

Other stuffs

http://github.com/scrum8

Django is not a silver bullet

But it's really helpful to build a website quickly

Resources Documentations http://docs.djangoproject.com/ Books http://www.djangobook.com/en/2.0/ Mailing lists [email_address] [email_address]

Documentations

http://docs.djangoproject.com/

Books

http://www.djangobook.com/en/2.0/

Mailing lists

[email_address]

[email_address]

Thank You! [email_address] http://slideshare.net/jpartogi