Django framework development process and best practices

The Django framework is a web application framework developed using the Python language. It uses the MVC (Model-View-Controller) software architecture pattern and the DRY (Don't Repeat Yourself) design principle. It is extremely fast to develop as the optimized Python code and built-in tools allow developers to build web applications quickly. This article will introduce the development process and best practices of the Django framework and provide some code examples.

1. Installing Django and creating projects

Before you start using Django, you need to install Python and Django. After installing Python, you can use the following command to install the latest version of Django:

pip install django

After the installation is complete, you can use the following command to create a new Django project:

django-admin startproject projectname

In this command, " projectname" is the project name. This command will create a new Django project and a Python file named "manage.py" in the root directory of the project. This file is used to manage Django applications during development.

2. Creating Django Applications

In Django, you can create multiple applications to organize and manage application code. The following command will create a new application named "appname":

python manage.py startapp appname

In this command, "appname" is the application name. This command will create a new application directory, "appname", in the root of the Django project and automatically generate some default files such as models, views, and controllers.

3. Writing Models

Models are one of the most important components of a Django application. They are used to define the structure and relationships of data, usually corresponding to database tables. Here is a simple model example that defines the structure of a student:

from django.db import models

class Student(models.Model):
    first_name = models.CharField(max_length=50)
    last_name = models.CharField(max_length=50)
    email = models.EmailField(max_length=254)
    phone = models.CharField(max_length=15)

    def __str__(self):
        return "{0} {1}".format(self.first_name, self.last_name)

In the above code, "Student" is the name of the model. It contains the student's "first_name", "last_name", email, and phone number. By using the model object, a new student record can be created in the database.

4. Writing views

Views are one of the cores of the Django framework. Views are Python functions or methods that handle HTTP requests and return HTTP responses. Views can render HTML templates, passing model data into the template for rendering. Here is an example of a view:

from django.shortcuts import render
from .models import Student

def student_list(request):
    students = Student.objects.all()
    context = {'students': students}
    return render(request, 'students/student_list.html', context)

In the above code, "student_list" is the name of the view function. This function queries all students by using the "Student" model and stores the results in the "students" variable. Next, use the "render" function to render the results into the "student_list.html" template.

5. Writing Templates

Templates are typically used to define the look and feel of a website, as well as to render data passed from views. Django uses a template engine to render HTML templates and inject data received from views into the templates. The following is a simple template example:

{% extends 'base.html' %}

{% block content %}
<table>
  <thead>
    <tr>
      <th>First Name</th>
      <th>Last Name</th>
      <th>Email</th>
      <th>Phone</th>
    </tr>
  </thead>
  <tbody>
    {% for student in students %}
    <tr>
      <td>{{ student.first_name }}</td>
      <td>{{ student.last_name }}</td>
      <td>{{ student.email }}</td>
      <td>{{ student.phone }}</td>
    </tr>
    {% endfor %}
  </tbody>
</table>
{% endblock %}

In the above code, the "{% extends 'base.html' %}" directive indicates that the template extends the base template. The content between the "{% block content %}" and "{% endblock %}" directives defines the main content of the template. Use the "{% for student in students %}" directive to loop through all students and render them in the template using appropriate HTML tags.

6. Testing the Application

Write and run automated tests using Django’s “unittest” module. Views, models, and URLs can be tested to ensure application correctness. Here is a simple test view example:

from django.test import TestCase
from django.urls import reverse

class StudentListViewTestCase(TestCase):
    def setUp(self):
        self.url = reverse('students:student_list')

    def test_student_list_view_correct_template(self):
        response = self.client.get(self.url)
        self.assertTemplateUsed(response, 'students/student_list.html')

    def test_student_list_view_context(self):
        response = self.client.get(self.url)
        self.assertTrue('students' in response.context)
        self.assertTrue(len(response.context['students']) == 0)

In the above code, the "setUp" method is used to set the view URL before each test case. In the "test_student_list_view_correct_template" test case, use the self.client.get method to access the view by accessing the URL and use the "assertTemplateUsed" method to check that the correct HTML template is used to render the view. In the "test_student_list_view_context" test case, check if the "students" variable exists in the template context by checking the "response.context" property and make sure its value is zero.

Best Practices

1. Use models to represent data structures and relationships

Django’s model is the core of the ORM (Object Relational Mapping) system. Model classes define data structures and relationships and map them into database tables. Using models, you can avoid manually managing database tables and take advantage of Django's built-in advanced features like queries, joins, and data validation.

2. Separating views and templates

Separating views and templates is a best practice in Django development, which helps classify and organize the code. Views handle data, while templates are primarily responsible for presentation. Maintainability of the application is ensured through clear views and template design.

3. Try using Django’s built-in features

Django provides a large number of built-in features that can speed up the web application development process. Using Django's built-in ORM, forms, security, URL routing, and template engine, you can avoid writing a lot of duplicate code and ensure the quality and stability of your application.

4. Use Django’s default settings

Django’s settings contain all configuration values ​​used in the application. Using appropriate default settings can improve performance, security, and usability. Optimizing settings can greatly reduce code errors and vulnerabilities and improve application maintainability.

5. Writing Automated Tests

Writing automated tests can help find and resolve errors in your application. Django provides a powerful testing framework that can be used to automate testing of critical parts of Django applications. Writing test cases maintains the stability of the application throughout the development cycle and ensures that new features developed do not break other parts of the application.

Conclusion

Django is a simple, flexible and powerful web framework. Use its built-in features, optimized settings, and automated testing methods to build highly maintainable and scalable web applications. Django's development process is clear and simple, allowing application development to be carried out quickly and efficiently.

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