Django Tutorial - Part I

Reference: 
Django Project / Django Book

Django web framework / Python web development with Django

Django is a high-level Python Web framework that encourages rapid development and clean, pragmatic design.
The tage line for Django is "The web framework for perfectionists with deadlines"
Django makes it easier to build Web apps more quickly and with less code, mainly used for web development

Main components of The Django framework

Object-relational mapper
Define your data models entirely in Python. You get a rich, dynamic database-access API for free, but you can still write SQL if required.
If your web application is data extensive, better write your SQL instead of object-relational mapper

Automatic admin interface
It comes with Admin interface, you need to enable it in the web framework
There by saving extra effort in creating the admin interface from the scratch

Elegant URL design
Very Flexible URL design using loose coupling
URL definitions and the view functions they call are loosely coupled; that is, the decision of what the URL should be for a given function, and the implementation of the function itself, reside in two separate places. This lets you switch out one piece without affecting the other.
Map the URLs and view methods, if you want to change the URL pattern later, you can do it very easily by changing urls.py
It makes use of regular expression for mapping the URL patterns
It generates dynamic URLs as well

Template system
Use Django's powerful, extensible and designer-friendly template language to separate design, content and Python code.

Cache system
Hook into memcached or other cache frameworks for super performance — caching is as granular as you need.

Internationalization
Django has full support for multi-language applications, letting you specify translation strings and providing hooks for language-specific functionality.

How to Install Django

Download Django (https://www.djangoproject.com/download/) and unzip

django-admin.py should be on your system path if you installed Django via its setup.py utility.
on Windows, you need to update your PATH environment variable.

python setup.py install
python -c 'import sys, pprint; pprint.pprint(sys.path)' #this locate site-packages direcotry

How to check Django Installed

>>> import django
>>> django.VERSION
(1, 4, 2, 'final', 0)

How to create a project

django-admin.py startproject <proj_name>
E.g., django-admin.py startproject mysite

Django Project Structure

The startproject command creates a directory containing five files:
mysite/
    manage.py
    mysite/
        __init__.py
        settings.py
        urls.py
        wsgi.py

How to access Django from shell

python manage.py shell

Django Development Server

Django comes with its own development server

Difference between Django Development Server Vs Web Development Server like Apache is as mentioned below :

Advantage:
Comes as part of Django itself
You can develop your site rapidly without having to deal with configuring your production server (e.g., Apache) until you are ready for production
Django Development server watches your code and automatically reloads it. making it easy for you to change code without restarting server

Disadvantage:
Not suitable for production environment
You have to deploy your code to Apache when moving to production

Django Development Server suitable in development environment
Apache web development server suitable in production environment

How to start Django Development Server

Django develeopment server works on default port 8000
python manage.py runserver 8000

How to test home page on Web Page

Using Django Development Server
http://127.0.0.1:8000/

Using Apache Server (If you configure Apache)
http://127.0.0.1/mysite/

How to configure Apache with Django

In Apache httpd.conf
WSGScriptAlias /mysite "C:/django_workspace/mysite/mysite/wsgi.py"


Thanks for reading this article. I will discuss more examples in the coming sessions, stay tuned :-)