The most complete guide to building web applications with Python and Django

With the popularity of the Internet and the prosperity of e-commerce, Web application development has attracted more and more attention. As one of the most popular web development languages ​​and frameworks, Python and Django are widely used to develop various types of applications, such as social networks, blogs, e-commerce platforms, etc. This article will introduce you to how to use Python and Django to build a successful web application. This article mainly includes the following content:

1. What are Python and Django?
2. Advantages and Disadvantages of Python and Django
3. Steps to Build Web Applications with Python and Django
4. What are Python and Django?

Python is a high-level programming language created by Guido van Rossum in 1989. Python's design philosophy emphasizes code readability and clarity, as well as code maintainability and reusability. Python is an object-oriented programming language with powerful data structures and dynamic typing. Python is widely used in the field of web application development due to its ease of learning, ease of use and efficiency.

Django is a web framework, which is one of the most popular web frameworks in the Python language. Django was created by Adrian Holovaty and Simon Willison originally to support numerous news websites.

Django adopts the MTV pattern (Model-Template-View) to organize the application architecture, making the code structure clear and easy to maintain. Django provides many tools and libraries, such as forms, template systems, authentication, management backend, etc., to facilitate developers to quickly build web applications.

2. Advantages and Disadvantages of Python and Django

Both Python and Django offer many advantages that make them popular choices in the field of web application development.

The advantages of Python include ease of learning and use, readability and clarity, powerful data structures and dynamic types, interpreted language, etc. These make Python a fast, efficient and consistent development language suitable for a variety of web application projects.

The advantages of Django include MTV mode, a large number of application and tool support, automated management background, etc. Django's MTV pattern forces developers to separate applications into clear components and makes application structure simple and rigid. Django also provides many built-in applications and tools, such as forms, authentication, template systems, static file processing, etc., which bring great convenience to developers.

The disadvantages of Python and Django include not being suitable for processing large-scale data, being slower than C/C, and requiring more memory and processor resources. For large-scale data processing projects, Python and Django may not be the best choices.

3. Steps to build a web application using Python and Django

Building a web application using Python and Django can be divided into the following steps:

First Step: Install Python and Django

Before you start building your web application, you need to install Python and Django on your computer. Python can be downloaded from the official website https://www.python.org/downloads/, and Django can be installed using the pip command. After installing Python, run the following command on the command line to install Django:

pip install django

Step 2: Create a Django project

Creating a Django project is very simple. In the command line, enter the directory where you want to store the project and run the following command:

django-admin startproject myproject

where "myproject" is the name of the project. After executing the command, a directory named "myproject" will be created in the current directory. The files and subdirectories inside are used to store various components of the Django project.

Step 3: Create an application

Applications in Django refer to various components of a web application, such as blogs, social networks, etc. Each application is an independent code package, and applications can be easily added or removed by reusing code. To create an application, go to the root directory of your Django project on the command line and run the following command:

python manage.py startapp myapp

where "myapp" is the name of the application. After executing the command, a directory named "myapp" will be created in the root directory of the Django project.

Step 4: Define the data model

The data model in Django refers to the class associated with data. Use ORM (Object Relational Mapping) in Django to handle data models. When creating a data model class, you need to inherit from Django's Model class and define each field and its data type. For example, the following code defines the Article class, which contains title, summary, and body fields:

from django.db import models

class Article(models.Model):
    title = models.CharField(max_length=200)
    summary = models.TextField()
    content = models.TextField()

Step 5: Create a view

A view in Django refers to a view that can return a web page or data Python functions. Views used in Django are usually functions, which can be imported from django.views. For example, the following code defines a hello_world view:

from django.http import HttpResponse

def hello_world(request):
    return HttpResponse("Hello, world!")

Step 6: Define the URL

In Django, the URL is responsible for determining which view should be run when a request is made. In order to associate URLs with views, create a file called "urls.py" in the root directory of your Django project. In this file, URL patterns can be defined using the urlpatterns list. For example, the following code defines the URL pattern for the hello_world view:

from django.urls import path
from . import views

urlpatterns = [
    path('hello-world/', views.hello_world, name='hello_world'),
]

The above code defines the /hello-world/ URL, which will map to a view named "hello_world".

Step 7: Define the template

在Django中，模板是一种用于生成Web页面的框架。模板使用变量、标记和过滤器来渲染页面。在Django中的模板存储在应用程序中的“templates”目录中。例如，以下代码定义了一个名为“article.html”的模板：

<!DOCTYPE html>
<html>
<head>
  <title>{{ article.title }}</title>
</head>
<body>
  <h1>{{ article.title }}</h1>
  <p>{{ article.content }}</p>
</body>
</html>

第八步：创建视图函数

视图函数是Django中的一个组件，它能够处理URL请求并返回HttpResponse对象。在本例中，我们将创建一个视图函数来处理文章的请求。在views.py文件中，我们将定义一个名为“article_view”的视图函数，该函数必须接受一个request参数。

def article_view(request):
    article = Article.objects.get(id=1)
    context = {
        'article': article,
    }
    return render(request, 'article.html', context)

第九步：更新URL配置

现在，我们需要更新URL配置以便Django可以将请求发送到我们的新视图函数。我们将根据层次结构将托管于URLConfs中的URL分配。

from django.urls import path
from . import views

urlpatterns = [
    path('articles/', views.article_view, name='article'),
]

第十步：创建模板

为文章添加模板：为了渲染我们刚定义的视图，您需要将内容放入一个模板中。为了让代码更具可扩展性，让我们创建一个基本模板文件。

<!doctype html>
<html lang="en">
<head>
  <title>Basic Template</title>
</head>
<body>
  {% block content %}{% endblock %}
</body>
</html>

现在你有了一个文章应用程序，你可以通过url "/articles/" 下载这个视图。

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