The Django Web Framework (EuroPython 2006)

The Django Web FrameworkSimon Willisonhttp://simonwillison.net/EuroPython, 3rd July 2006

Web development onJournalism deadlines

... in three days

Characteristics Clean URLs Loosely coupled components Designer-friendly templates Less code Really fast development

Components

URL dispatching

http://www.example.com/poll/5/ What code shall we execute?

(r^$, views.index),(r^hello/$, ‘views.hello),(r^poll/(d+)/$, ‘views.poll),

def index(request): s = "Hello, World" return HttpResponse(s)

def index(request): name = request.GET[name] s = "Hi, " + escape(name) return HttpResponse(s)

Models

...(r^poll/(d+)/$, views.poll),...

...(r^poll/(d+)/$, views.poll),...def poll(request, poll_id): poll = Poll.objects.get( pk=poll_id ) return HttpResponse( Question: + poll.question )

class Poll(Model): question = CharField(maxlength=200) pub_date = DateTimeField()class Choice(Model): poll = ForeignKey(Poll) choice = CharField(maxlength=200) votes = IntegerField()

BEGIN;CREATE TABLE "polls_poll" ( "id" serial NOT NULL PRIMARY KEY, "question" varchar(200) NOT NULL, "pub_date" timestamp with time zone NOT NULL);CREATE TABLE "polls_choice" ( "id" serial NOT NULL PRIMARY KEY, "poll_id" integer NOT NULL REFERENCES "polls_polls" ("id"), "choice" varchar(200) NOT NULL, "votes" integer NOT NULL);COMMIT;

p = Poll( question = "Whats up?", pub_date = datetime.now())p.save()p.choice_set.create( choice = "Some choice", votes = 0)

>>> p.id1>>> p.question"Whats up?">>> p.choice_set.all()[<Choice: Some choice>]

>>> Poll.objects.count()7>>> Poll.objects.filter( pub_date__year = 2006, pub_date__month = 5)["Whats up?"]>>> Poll.objects.all()[0:2]["Whats up", "Like Django?"]

Templates

Gluing strings together gets old fast

c = Context({ today: datetime.date.today(), edibles: [pear, apple, orange]})

<h1>Hello World!</h1><p>Today is {{ today|date:"jS F, Y" }}</p>{% if edibles %}<ul> {% for fruit in edibles %} <li>{{ fruit }}</li> {% endfor %}</ul>{% endif %}

<h1>Hello World!</h1><p>Today is 2nd July, 2006</p><ul> <li>pear</li> <li>apple</li> <li>orange</li></ul>

def hello(request): return render_to_response(hello.html,{ today: datetime.date.today(), edibles: [pear, apple, orange] })

Common headers and footers?

Template inheritance

home.html{% extends “base.html” %}{% block title %}Homepage{% endblock %}{% block main %}Main page contents goes here.{% endblock %}

Loosely coupled

Bengali Japanese Czech Dutch Welsh Norwegian Danish BrazilianGerman Romanian Greek Russian English Slovak Spanish Slovenian French Serbian Galician SwedishHebrew UkrainianIcelandic Simpliﬁed Chinese Italian Traditional Chinese

msgid "Usernames cannot contain the @ character."msgstr "Імя не може містити @ символ"

Forms are boring

1. Display form2. Validate submitted data3. If errors, redisplay with: 3.1. Contextual error messages 3.2. Correct fields pre-filled4. ... do something useful!

Model validation rules+ the Manipulator API do all of this for you

The admin package does even more

No time to talk about... Generic views Data object serialisation Syndication framework Middleware Authentication and authorisation

Success stories

170+ public Django-powered sites http://code.djangoproject.com/wiki/DjangoPoweredSites90+ contributors1900+ mailing list subscribers (and 900+ onthe development list)And the Journal-World have convinced threenew people to go and work in Kansas

Find out more

www.djangoproject.com

The Django Web Framework (EuroPython 2006)

by Simon Willison on Aug 02, 2012

Accessibility

Categories

Upload Details

Usage Rights

1 Embed 12

Statistics