Django Programming: A Complete Guide from Theory to Practice

Django is an open source web application framework written in Python language. Since its release, it has become one of the preferred frameworks for developing high-quality web applications.

This article will introduce you to the basics of Django, including a complete guide from theory to practice. We will cover the following:

1. Django’s background and development history
2. The basics of Django
3. Django’s MVC architecture and MTV architecture
4. Django’s routing system and views
5. Django’s template system
6. Django’s form processing
7. Django’s database access
8. Django’s user authentication system
9. Django's Web server and deployment
10. Django's background and development history

Django appeared in 2005 and was created by a group of news group editors and programmers. They created a framework for handling large amounts of web content. The main goal of Django is to provide a simple framework for developing web applications.

The Django program framework has a well-known name: The Web framework for perfectionists with deadlines. This is because Django emphasizes development standards such as fast, efficient, simple, safe and scalable.

2. Basic knowledge of Django

Django is based on the MVC design pattern, which splits the program into three parts: Model, View and Controller. These components divide the program into data, user interface, and bridge parts. Django calls MVC the MTV architecture and introduces the Template layer.

Django core components include:

• Routing system: used to map a URL address to a program view
• View system: template displayed in the front-end user interface Series
• ORM Object Relational Mapping: used to manage data in the database
• Middleware: By extending the middleware class that sends requests and receives responses

3. Django’s MVC architecture and MTV architecture

The goal of the MVC pattern is to split an application into three components: Model, View and Controller. The Model is the data part of the application. It contains components of application data. View is part of the user interface of the application. It is responsible for the interaction between interface and data. Controller is the bridge of MVC. It connects Model and View. Controller handles all application logic in MVC.

Django introduces the MTV architecture. In MTV, Model is the part of the database that stores data. The Template layer is the View part of MTV. In MTV, View is the logical part and can be written using Python. Views respond to requests from a specific URL and include all the logic to retrieve data from the database and assemble it into a template.

A simple MTV example can be seen as a template representing a list of students. The database stores information about all students. The view retrieves data from the database and passes it into the template so that the user can manage all students' information.

4. Django’s routing system and views

Django’s routing system maps the requested URL address to the view function. A URL address is a string that indicates the location and view of the page that the application needs to display.

Using Django's routing system, complex routing can be handled using standard regular expression syntax or template views. For example, the following type of routing can be used:

For example, we can map the URL /admin to a view by adding the following to the urls.py file: admin_site.site.urls:

  from django.contrib import admin
  from django.conf.urls import url, include
   
  admin.autodiscover()
   
  urlpatterns = [
      url(r'^admin/', admin.site.urls),
  ]

5. Django’s template system

Django’s template system enables developers to use templates to efficiently build code in websites. The Django template engine allows templates to be fully converted into HTML code before writing the logic in Python.

Some basic concepts of templates include:

• Template variables: enclosed by double curly brackets {{}}. Template variables are placeholders that need to be replaced with actual values ​​when rendering.
• Template tag: enclosed by curly braces {% %}. Template tags will control how the template is rendered. For example, {% if %} brackets are used to use conditions in templates.
• Template filter: Modifier used on template variables.

6. Django's form processing

Django's form processing system is a part of the web application that handles input and output to the database. Django requires developers to define a form class, which defines how the form is displayed on the page. The advantage of this is that it allows developers to understand the specific details of the form, increasing the security and maintainability of the application.

Key classes for form processing include:

• Form: Define each field of the form
• ModelForm: Automatically create a form from a model
• FormView: Process forms and display templates

7. Django’s database access

Django ORM is an advanced object-relational mapping framework. ORM allows developers to write model classes using Python and map them to database tables. Django ORM provides a data access layer that allows data structures to be described through models.

ORM has two main aspects: model definition and data manipulation. A model definition describes an entity in an application and defines properties for that entity. Data manipulation is the process of converting between entities and data stored in the database.

The main features of ORM include:

• Pythonic: Using Python’s data types and syntax landscape
• Model-centric: The model is by far the most important part
• DRY: Data definition and manipulation together
• Plug-in: supports multiple ORMs and databases
• Extensive query API: including complex queries and connections

8. Django’s user authentication system

Django has a built-in user authentication system, which is a standard way to manage user authentication in web applications. The user authentication system includes:

• Registration of username and password
• Login/logout
• Computer side verification and session security

The Django user authentication system has the following authentication backends built in:

• User
• PasswordResetToken
• EmailVerificationToken
• SocialAuthenticatio

9. Django's Web server and deployment

In a production environment, Django recommends using mature web servers such as Apache and nginx. Django also provides a Python WSGI HTTP server called Gunicorn, which is a lightweight web server integrated with Django.

We can start the Gunicorn server using the following command:

gunicorn myproject.wsgi: application -w 2 -b: 8000

Django also provides a method called Fabric Deployment tools. By using Fabric, Django developers can easily set up and deploy Django web applications.

Summary

Django is an efficient, simple, fast, scalable and secure web application framework. It adopts the MTV architecture, has a built-in ORM system and user authentication system, and also provides a flexible template system and powerful form processing.

Our guide provides the basics and introduces key aspects of Django development, including the routing system, view handling, database access, form processing, web servers, and deployment. Hope this article helps you get started with Django programming.

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