In this inaugural article, we embark on a journey to demystify Django, a high-level Python web framework. We’ll explore its key features, its origins, and what sets it apart in the world of web development. By the end of this article, you’ll have a solid grasp of Django’s fundamentals and why it’s a top choice […]
In this inaugural article, we embark on a journey to demystify Django, a high-level Python web framework. We’ll explore its key features, its origins, and what sets it apart in the world of web development. By the end of this article, you’ll have a solid grasp of Django’s fundamentals and why it’s a top choice for building web applications.
Prerequisites
Before we dive in, let’s clarify the prerequisites for this journey:
- Basic Computer Literacy: You should be comfortable with using a computer.
- Understanding of Server-Side Website Programming: Familiarity with the concepts of server-side programming will be beneficial.
- Client-Server Interactions: A basic understanding of how clients (like web browsers) interact with servers in the context of websites.
Objective
Our primary objective is to introduce you to Django, shedding light on what it is, the functionality it offers, and the core building blocks of a Django application.
What is Django?
Django is a Python web framework designed to expedite the development of secure and maintainable websites. Developed by experienced programmers, Django streamlines web development, allowing you to focus on crafting your application without reinventing the wheel. Here’s why Django stands out:
1. Completeness
Django adheres to the “Batteries included” philosophy, offering almost everything a developer might need “out of the box.” With all essential components seamlessly integrated, Django maintains consistency in design principles and provides extensive, up-to-date documentation.
2. Versatility
Django’s versatility shines through its ability to construct a wide range of websites, from content management systems to social networks. It plays well with various client-side frameworks and can deliver content in multiple formats, including HTML, RSS feeds, JSON, and XML. While it provides default choices for various functionalities (like databases and templating engines), it remains highly extensible to accommodate other components when needed.
3. Security
Django takes security seriously, helping developers avoid common security pitfalls. It offers secure user account and password management, protecting against vulnerabilities such as SQL injection, cross-site scripting, cross-site request forgery, and clickjacking. Passwords are stored as hashes, making it challenging for attackers to decipher the original password even if the hash is compromised.
4. Scalability
Django embraces a component-based “shared-nothing” architecture, allowing independent scaling of different parts of the application, whether it’s caching servers, database servers, or application servers. Several high-traffic websites, including Instagram and Disqus, have successfully scaled Django to meet their demands.
5. Maintainability
Django encourages the creation of maintainable and reusable code by adhering to principles like “Don’t Repeat Yourself” (DRY). It promotes the organization of related functionality into reusable “applications” and modularizes code following the Model-View-Controller (MVC) pattern.
6. Portability
Being written in Python, Django enjoys broad platform support, freeing you from platform lock-in. You can run Django applications on various operating systems, and many web hosting providers offer dedicated infrastructure and documentation for Django sites.
Where Did Django Come From?
Django’s roots trace back to its initial development between 2003 and 2005. It was crafted by a web development team responsible for creating and maintaining newspaper websites. As they accumulated common code and design patterns across multiple projects, this shared codebase eventually evolved into the open-source “Django” project in July 2005.
Django has evolved continuously since its first milestone release (1.0) in September 2008. Each release has introduced new functionalities, bug fixes, and support for diverse databases, template engines, and caching mechanisms. Today, Django thrives as a collaborative open-source project with a vibrant community of users and contributors. While it retains some of its original features, Django has matured into a versatile framework capable of building a wide array of websites.
How Popular is Django?
Measuring the popularity of server-side frameworks can be challenging, but Django’s prominence is evident. High-profile websites like Disqus, Instagram, Mozilla, National Geographic, Pinterest, and more rely on Django to power their platforms. The growing number of contributors, extensive documentation, and both free and paid support options attest to Django’s popularity and continued evolution.
Is Django Opinionated?
Frameworks often classify themselves as “opinionated” or “unopinionated.” Let’s clarify Django’s stance:
- Opinionated Frameworks: These frameworks have strong opinions about the “right way” to perform specific tasks, often within a well-defined domain. While they excel in their chosen domain, they might offer limited flexibility for tasks outside that domain.
- Unopinionated Frameworks: Unopinionated frameworks provide more freedom, allowing developers to choose from various components and approaches to tackle tasks. While they offer flexibility, they may require more decisions and configuration.
Django finds itself in a middle ground, being “somewhat opinionated.” It offers a set of components and preferred methods for common web development tasks. However, Django’s decoupled architecture permits you to mix and match components or incorporate entirely new ones as needed, providing flexibility without overwhelming choices.
What Does Django Code Look Like?
In a typical data-driven website, a web application processes HTTP requests from clients, retrieves or manipulates data as required, and returns HTTP responses. Django structures its code into distinct files to manage these steps:
1. URLs (urls.py)
URL routing plays a crucial role in Django. In the urls.py file, URL patterns are defined, mapping specific URL patterns to corresponding view functions. These view functions handle incoming HTTP requests based on the URL.
2. Views (views.py)
Views act as request handlers, receiving HTTP requests and crafting HTTP responses. Views access data through models and delegate response rendering to templates. View functions take an HttpRequest object as input and return an HttpResponse.
3. Models (models.py)
Django models define the data structure and offer mechanisms for managing and querying records in the database. Models are Python objects representing data entities and their relationships.
4. Templates
Templates define the structure of output documents, such as HTML pages. They include placeholders for dynamic data, allowing views to populate these placeholders with content before rendering the final output.
Sending the Request to the Right View (urls.py)
In the urls.py file, URL patterns are mapped to view functions. For instance, a URL mapper might redirect HTTP requests to an appropriate view function based on the request URL. Django’s URL mapper can also capture and pass specific URL components as named arguments to view functions.
python
urlpatterns = [
path('book/<int:book_id>/', views.book_detail),
]
Handling the Request (views.py)
View functions in Django receive HTTP requests and return HTTP responses. They serve as intermediaries, interacting with models to access data and using templates to render responses. Here’s a simple example of a view function:
python
from django.http import HttpResponse
def index(request):
return HttpResponse(“Welcome to our website!”)
Defining Data Models (models.py)
Django models define the structure of data stored in the application. Models encompass data fields, relationships, and database-specific details. Below is a basic Django model for a Team object:
python
from django.db import models
class Team(models.Model):
team_name = models.CharField(max_length=100)
team_level = models.CharField(
max_length=3,
choices=[(‘U09’, ‘Under 9’), (‘U11’, ‘Under 11’)],
default=‘U09’
)
Querying Data (views.py)
Django models come with a straightforward query API for database interactions. You can filter, retrieve, and manipulate data efficiently. For instance, the code below fetches all teams with the level ‘U09’:
python
def list_teams(request):
youngest_teams = Team.objects.filter(team_level__exact="U09")
return render(request, 'team_list.html', {'teams': youngest_teams})
Rendering Data (HTML Templates)
Templates define the structure of output documents and placeholders for dynamic data. Views populate these placeholders with actual content before rendering the final output. Here’s an example of an HTML template:
html
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Team List</title>
</head>
<body>
<ul>
{% for team in teams %}
<li>{{ team.team_name }}</li>
{% endfor %}
</ul>
</body>
</html>
What Else Can You Do with Django?
Django offers a plethora of features beyond the basics we’ve covered. Some notable ones include:
– Forms
Django simplifies form creation, validation, and processing, making it effortless to collect user data for server-side processing.
– User Authentication and Permissions
Django includes a robust user authentication and permission system with a strong focus on security.
– Caching
Caching is crucial for optimizing performance. Django provides flexible caching options to store rendered pages and reduce computational overhead.
– Administration Site
Django’s administration site, included by default, facilitates the creation, editing, and viewing of data models for site administrators.
– Serializing Data
Django streamlines the serialization of data, enabling easy serving of data as XML or JSON. This is particularly useful for creating web services or data-centric websites.
Conclusion
Congratulations! You’ve completed the first step in your Django journey. You now have a firm understanding of what Django is, its key benefits, its origin story, and the core components of a Django application. While you’ve glimpsed real Django code, the next step on your journey is to set up a development environment to run it effectively. Stay tuned for the next installment!