DED9

What Is Django And Why Is It One Of The Most Popular Web Application Development Frameworks?

Herbert Huffner

Django Is A Python-based Web Application Development Framework That Enables The Rapid Development Of Secure, Highly Maintainable Websites.

Django helps web developers write clean, efficient, and robust code. Besides being among the most popular web frameworks, it is one of the most widely used web development technologies.

The mentioned framework has been used by popular platforms such as Instagram, YouTube, Google, etc. Django allows developers to produce applications faster by writing less code.

In addition, it is free and open source, supported by an active developer community, has excellent documentation, and provides developers with many valuable features.

How did Django come about?

Django was first developed in 2003 by Adrian Holovaty and Simon Willison and demonstrated its ability to handle high-traffic sites. Over the years, various versions of this framework have been published, the latest version of which is version 4.0, which was released in 2022.

Today, Django is a collaborative open source project with a wide range of developers worldwide actively involved in its development and bug fixes. In general, Django came about for the following reasons:

General familiarity with Django architecture

Django is a platform for developing web-based applications using Python and supports MVC and MVT architectures. When we talk about applications with a user interface, we’re referring to a specific architecture called the Model-View-Controller (MVC) architecture. As it is clear from the name of the mentioned architecture, the MVC architecture consists of three components: Model, View, and Controller. MVT architecture is slightly different from MVC architecture.

The main difference between the above two architectures is that the Django library manages the controller component in the MVT model. The controller component is the software code that controls the interaction between the model and display components.

Considering that, in the MVT architecture, the Django library manages the controller component, it also monitors the operation of the Template component. The Template component is an HTML file combined with the Django Template Language.

Figure 1 shows how different components of the MVT architecture interact with each other to serve the user’s request. Based on the mentioned architecture, the developer defines the Model module, then, using View and Template, the specified Model is mapped to an Internet address. Finally, the Django platform provides the desired content or service to the user.

figure 1

Why do developers use Django?

Django provides the following features to developers:

A password hash is a fixed-length value that encrypts the password using a hash function. Once the password is encrypted, the hash function is then used to compare the output of the hash with the original value to confirm the correctness of the password. Due to the one-way nature of the function, if the stored hash value is tampered with, Django will quickly notice this, preventing hackers from easily gaining access to passwords.

Django’s great benefits are protecting web-based applications against vulnerabilities such as SQL code injection, cross-site scripting, cross-site request forgery, and clickbait.

What does Django code look like in programing?

Data may be read or written to a database depending on what is needed. In a traditional data-driven website, a web application waits for HTTP requests from the user’s web browser. The application checks the requirements when a request is received based on the URL and the POST or GE information data.

The program then sends a response to the web browser, often dynamically creating and sending an HTML page so the browser can display the received data correctly in HTML format. Typically, Django web-based programs put the codes needed to perform the mentioned steps in separate files (Figure 2). The components shown in Figure 2 are as follows:

figure 2

As we mentioned at the beginning of the article, Django supports MVT and MVC, and the above pattern is based on the MVT architecture.

Send the request to the correct display function (urls.py)

Typically, a URL mapper is stored in a file called urls.py. In the following code snippet, the mapper (URL patterns) defines a list of mappings between paths (specific url patterns) and the corresponding display functions.

If an HTTP request with a URL matching the specified pattern is received, the corresponding display function is called, and the request is sent. The following code snippet illustrates this.

URL patterns = [

path(‘admin/’, admin.site.urls),

path(‘book/<int:id>/’, views.book_detail, name=’book_detail’),

path(‘catalog/’, include(‘catalog.urls’)),

re_path(r’^([0-9]+)/$’, views.best),

]

Request handling and management (views.py)

The View component is the heart of web applications. It receives HTTP requests from web clients and returns HTTP responses. For this purpose, display components have access to databases, processing patterns, etc.

The following code snippet shows an index display function that can be called by the URL mapper component of the previous code snippet. The following code snippet takes an HttpRequest object as a parameter (request) and returns an HttpResponse object. In this case, we don’t do anything with the request and get the response as a string.

# filename: views.py (Django view functions)

from Django.HTTP import HttpResponse

def index(request):

# Get an HttpRequest – the request parameter

# perform operations using information from the request.

# Return HttpResponse

return HttpResponse(‘Hello from Django!’)

Views are stored in a file called views.py.

Defining data models (models.py)

Django -based web applications manage and interact with data through Python objects called “models.” Models define stored data structure such as field types and maximum sizes, default values, picklist options, help text for documents, label text for forms, etc. The model definition is independent of the underlying database.

The code snippet below is a straightforward Django model for a Team object. The Team class is derived from the models. Model class. The following code snippet defines team name and team level as character fields. Also, the maximum number of characters stored for each record is specified. team_level can be one of several values; Hence, we define it as an optional field and provide a mapping between the displayed options and the stored data along with a default value.

# filename: models.py

from Django.DB import models

class Team(models. Model):

team_name = models.CharField(max_length=40)

TEAM_LEVELS = (

(‘U09’, ‘Under 09s’),

(‘U10’, ‘Under 10s’),

(‘U11’, ‘Under 11s’),

…  #list other team levels

)

team_level = models.CharField(max_length=3, choices=TEAM_LEVELS, default=’U11’)

Running queries on data (views.py)

The Django model provides programmers with a functional programming interface to run simple queries on the database. The above interface can work with several fields simultaneously using different criteria and support complex expressions. The following code snippet shows a display function (resource controller) to display all U09 teams.

The line list_teams = Team.objects.filter(team_level__exact=” U09″) shows how we can use the model query API to filter out all records where the team_level field has exactly the value “U09” (note how this criterion acts as a filter for the argument).

## filename: views.py

from Django. shortcuts import render

from .models import Team

def index(request):

list_teams = Team.objects.filter(team_level__exact=”U09”)

context = {‘youngest_teams’: list_teams}

return render(request, ‘/best/index.html’, context)

The code above uses the render function to create an HttpResponse sent to the browser and act as a shortcut. The above code snippet creates an HTML file by combining a specified HTML template and some data added to the format (provided in a variable called context).

Data processing (HTML templates)

Templates allow you to specify the structure of an output document in which data is to be placed. Templates are most often used to create HTML, but they can make other types of documents.

Django supports its native template system and a popular Python library called Jinja2. The following code snippet shows what the render function calls the HTML template. The template is written assuming it will access a list variable called Youngest_teams when processed.

In the HTML body, we have a command that checks whether the Youngest_teams variable exists and reads its content through a loop.

The template displays the team_name value via each iteration’s <li> element.

## filename: best/templates/best/index.html

<!DOCTYPE html>

<html lang=”en”>

<head>

<meta charset=”utf-8”>

<title>Home page</title>

</head>

<body>

{% if youngest_teams %}

<ul>

{% for the team in youngest_teams %}

<li>{{ team.team_name }}</li>

{% endfor %}

</ul>

{% else %}

<p>No teams are available.</p>

{% endif %}

</body>

</html>

 

Die mobile Version verlassen