Introduction to Django

Introduction to Django

Avlayev Elbobo

Django “””The web framework for perfectionists with deadlines.”””

• “”” Django is a high-level Python web framework that encourages rapid development and clean, pragmatic design.””“

https://www.djangoprojects.com/

What is inside?

• Built-in ORM(Object-relational Mapper)
• ● Simple but powerful URL system
• ● Built-in template system
• ● I10n(Internationalization)
• ● Cache system
• ● Built-in authentication system
• ● Built-in webserver(for development)
• ● Automatic admin interface

MVT not MVC

• Model
• ○ defines the data structure
• ○ takes care for querying the database
• ● View
• ○ defines what data should be presented
• ○ returns HTTP response
• ● Template
• ○ renders the data in suitable format - HTML/XML/etc

The live of request

Project structure

• To start new project run:
• django-admin.py startproject my_project
• The following structure will be created
• my_project/
• manage.py
• my_project/
• __init__.py
• settings.py # project settings reside here
• urls.py
• wsgi.py
• This is the default created and good for learning the basics but this way the
• settings may be hard to maintain for project in production. Alternative approach
• is available at http://ilian.i-n-i.org/django-project-file-structure/.

Application structure

• To create new application in you project just run the following command
• in the shell:
• python manage.py startapp app
• The following structure will be created
• app/
• __init__.py
• admin.py # not created automatically before 1.5
• models.py
• tests.py
• views.py
• There is no urls.py file but most developer find it useful to keep the application
• specific URLs inside it and include them in the main URLs configuration file.

Models

• # models.py
• from django.db import models
• from django.utils.translation import ugettext_lazy as _
• class News(models.Model):
• title = models.CharField(_('Title'), max_length=255)
• slug = models.SlugField(_('Slug'))
• content = models.TextField()
• To create the tables for the define models just run:
• python manage.py syncdb

URLs dispatcher

• # urls.py
• from django.conf.urls import patterns, url, include
• urlpatterns = patterns('',
• url(r'^$', 'app.home', name='home'), # give the specific URL meaningful
• name
• url(r'offers/', include('offers.urls')), # include URLs from another app
• (r'^news/$', 'news.views.offers'), # point to specific view
• (r'^news/(\d{4})/$', 'news.views.year_archive'), # pass arg(s)
• (r'^news/(\d{4})/(\d{2})/$', 'news.views.month_archive'), # pass arg(s)
• (r'^news/(?P[-\w]+)/$', 'news.views.single_news'), # pass named args
• )
• ● URLs dispatcher uses regular expression
• ● The first match found is called
• ● All arguments are passed as unicode strings

Views

• # views.py
• from .models import News
• from django.shortcuts import get_object_or_404
• def single_news(request, slug):
• news = get_object_or_404(News.objects.public(), slug=slug)
• return render_to_response('news/single_news.html', {'news': news})

Templates

• # template.html
• {% extends 'my_project/base.html' %}

• {{ news.title }}

• {{ news.content|safe }}