Django Auth Application Implements User Authentication

In this tutorial, we'll cover how to implement user authentication in your Django application using the built-in Django authentication app.

Prerequisites:

Basic knowledge of Python
Familiarity with Django framework
A Django project set up and running

Step 1: Set up Django authentication

1.1. Install the necessary packages, if not already done:

pip install django

1.2. Create a new Django project and app, if you haven't already:

django-admin startproject myproject
cd myproject
python manage.py startapp myapp

1.3. Enable the authentication middleware in your project settings. Open myproject/settings.py and make sure 'django.contrib.auth.middleware.AuthenticationMiddleware' is included in the MIDDLEWARE list.

Step 2: Configure Django authentication

2.1. In myproject/settings.py, make sure the following apps are included in the INSTALLED_APPS list:

INSTALLED_APPS = [
    # ...
    'django.contrib.auth',
    'django.contrib.contenttypes',
    'myapp',
]

2.2. Add a login URL and login redirect URL to myproject/settings.py:

LOGIN_URL = 'login'
LOGIN_REDIRECT_URL = 'home'

Step 3: Implement authentication views

3.1. Create a view for user registration in myapp/views.py:

from django.contrib.auth.forms import UserCreationForm
from django.contrib.auth import login
from django.shortcuts import render, redirect

def register(request):
    if request.method == 'POST':
        form = UserCreationForm(request.POST)
        if form.is_valid():
            user = form.save()
            login(request, user)
            return redirect('home')
    else:
        form = UserCreationForm()
    return render(request, 'myapp/register.html', {'form': form})

3.2. Create a view for the home page (where users will be redirected after login) in myapp/views.py:

from django.shortcuts import render

def home(request):
    return render(request, 'myapp/home.html')

Step 4: Implement authentication templates

4.1. Create a template for user registration in myapp/templates/myapp/register.html:

{% extends "myapp/base.html" %}

{% block content %}
  <h2>Register</h2>
  <form method="post">
    {% csrf_token %}
    {{ form.as_p }}
    <button type="submit">Register</button>
  </form>
{% endblock %}

4.2. Create a template for the home page in myapp/templates/myapp/home.html:

{% extends "myapp/base.html" %}

{% block content %}
  <h2>Welcome, {{ user.username }}!</h2>
{% endblock %}

4.3. Create a base template for your application in myapp/templates/myapp/base.html:

<!DOCTYPE html>
<html>
<head>
  <title>My Django App</title>
</head>
<body>
  <div>
    {% if user.is_authenticated %}
      <p>Welcome, {{ user.username }}! <a href="{% url 'logout' %}">Logout</a></p>
    {% else %}
      <p><a href="{% url 'login' %}">Login</a> | <a href="{% url 'register' %}">Register</a></p>
    {% endif %}
  </div>
  {% block content %}
  {% endblock %}
</body>
</html>

Django login view and authentication backend: Django's login view (django.contrib.auth.views.LoginView) uses an authentication backend to verify user credentials. You can customize the authentication backend for advanced scenarios.
```
# urls.py
from django.contrib.auth.views import LoginView

urlpatterns = [
    path('login/', LoginView.as_view(), name='login'),
]
```
Django authentication forms in auth app: Django provides authentication forms (django.contrib.auth.forms) for handling login, password reset, and other authentication-related tasks.
```
# forms.py
from django import forms
from django.contrib.auth.forms import AuthenticationForm

class CustomAuthenticationForm(AuthenticationForm):
    # Customizations here
```

User registration in Django auth application: While Django's auth app focuses on authentication, user registration involves creating a custom form and view for user creation.

# views.py
from django.contrib.auth.forms import UserCreationForm
from django.contrib.auth import authenticate, login

def register(request):
    if request.method == 'POST':
        form = UserCreationForm(request.POST)
        if form.is_valid():
            user = form.save()
            login(request, user)
            return redirect('home')
    else:
        form = UserCreationForm()
    return render(request, 'registration/register.html', {'form': form})