Master Django Basics: From Project Setup to Forms and Templates

Django Introduction

Django is a popular open‑source web application framework written in Python that follows the MVC (Model‑View‑Controller) design pattern.

Key Features of Django

Powerful ORM: define models as Python classes and perform database operations with minimal code.

Built‑in admin interface for easy content management.

Clean URL routing using regular expressions.

Extensible template system separating logic from presentation.

Integrated caching support (e.g., Memcached) for faster response.

Full internationalization and localization support.

Typical Django Project Layout

urls.py

: URL entry point mapping URLs to view functions or classes. views.py: Handles requests, renders templates, and returns responses. models.py: Defines data models and interacts with the database. forms.py: Manages form rendering and validation (optional). templates/: Stores HTML templates rendered by views. admin.py: Configures the automatic admin site. settings.py: Project configuration (debug mode, static files, etc.).

Basic Django Commands

Create a project: django-admin startproject project-name Create an app: python manage.py startapp app-name (or django-admin startapp app-name).

Run the development server: python manage.py runserver 0.0.0.0:8000 (or simply python manage.py runserver).

Views and URL Configuration

from django.http import HttpResponse

def helloWorld(request):
    return HttpResponse("Hello world! ")

from django.conf.urls import url
from . import view
urlpatterns = [
    url(r'^$', view.helloWorld),
]

Access the view at http://127.0.0.1:8000/ or /helloWorld after updating the URL pattern.

Django Template System

Example template helloWorld.html: <h1>{{ helloWorld }}</h1> Configure template directories in settings.py (add BASE_DIR + "/templates" to TEMPLATES['DIRS']).

from django.shortcuts import render

def hello(request):
    context = {'helloWorld': 'Hello World!'}
    return render(request, 'helloWorld.html', context)

Template tags include {% if %}, {% for %}, {% include %}, filters (e.g., {{ name|lower }}), and comments {# comment #}.

Models and Database Operations

Define a model in models.py:

from django.db import models
class Test(models.Model):
    name = models.CharField(max_length=20)

Configure the database in settings.py (example for MySQL):

DATABASES = {
    'default': {
        'ENGINE': 'django.db.backends.mysql',
        'NAME': 'test',
        'USER': 'test',
        'PASSWORD': 'test123',
        'HOST': 'localhost',
        'PORT': '3306',
    }
}

Run migrations:

python manage.py migrate
python manage.py makemigrations TestModel
python manage.py migrate TestModel

Basic CRUD examples:

# Create
test = Test(name='Alice')
test.save()

# Read
list = Test.objects.all()
for obj in list:
    print(obj.name)

# Update
test = Test.objects.get(id=1)
test.name = 'Alice'
test.save()

# Delete
test = Test.objects.get(id=1)
test.delete()

Form Handling (GET and POST)

GET form example ( search_form.html) and view:

def search_form(request):
    return render(request, 'search_form.html')

def search(request):
    if 'q' in request.GET:
        message = '搜索的内容为: ' + request.GET['q']
    else:
        message = '提交了空表单'
    return HttpResponse(message)

<form action="/search" method="get">
    <input type="text" name="q">
    <input type="submit" value="搜索">
</form>

POST form example ( post.html) with CSRF token and view:

def search_post(request):
    ctx = {}
    if request.POST:
        ctx['rlt'] = request.POST['q']
    return render(request, 'post.html', ctx)

<form action="/search-post" method="post">
    {% csrf_token %}
    <input type="text" name="q">
    <input type="submit" value="搜索">
</form>
<p>{{ rlt }}</p>

Update urls.py to include the new routes for the forms and database view.