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To return a 404 response in Django, you can use the Http404 exception or the get_object_or_404() utility function, which are both simple and efficient ways to handle cases where a resource is not found. Here’s how you can use each method:

1. Using Http404 Exception

You can raise the Http404 exception in your views when a certain condition is not met (e.g., when an object does not exist in the database). Here’s an example:

from django.http import Http404

def my_view(request, id):
    try:
        item = MyModel.objects.get(pk=id)
    except MyModel.DoesNotExist:
        raise Http404("Item does not exist")

    # Proceed with the rest of the view
    return render(request, 'template.html', {'item': item})

2. Using get_object_or_404()

Django provides a shortcut function get_object_or_404() that encapsulates the try-except block used with Http404. It tries to get an object from the model and if it fails, it automatically raises Http404. Here’s how to use it:

from django.shortcuts import get_object_or_404, render

def my_view(request, id):
    item = get_object_or_404(MyModel, pk=id)
    return render(request, 'template.html', {'item': item})

URL Configuration

To capture values from URLs, you define path converters in your URL patterns. Django offers several built-in path converters like str, int, slug, uuid, and more. You can also define custom path converters if needed.

Here’s an example of how to define a URL pattern that captures an integer value:

# urls.py

from django.urls import path
from . import views

urlpatterns = [
    path('article/<int:article_id>/', views.article_detail, name='article_detail'),
]

In this example, <int:article_id> is a dynamic segment. int is the converter that tells Django to convert this part of the URL into an integer. article_id is the name of the variable that will be passed to the view function.

View Function

In the view, you can capture the value from the URL as a parameter. Here’s how you might handle it:

# views.py

from django.http import HttpResponse

def article_detail(request, article_id):
    # You can now use `article_id` which is passed from the URL
    return HttpResponse(f"Displaying article {article_id}")

In the article_detail function, article_id is received as a parameter directly from the URL.

Using Captured Values

You can use these captured values to perform database queries, logic processing, or pass them into templates. For instance, to fetch an article from a database by its ID:

from django.shortcuts import get_object_or_404
from .models import Article

def article_detail(request, article_id):
    article = get_object_or_404(Article, pk=article_id)
    return HttpResponse(f"Title: {article.title}")

This function fetches an article using the captured article_id, and if the article does not exist, it raises a 404 error.

python manage.py startapp myapp

Register the App

Open the settings.py file in your project directory (myproject/myproject/settings.py). Add your new app to the INSTALLED_APPS list:

INSTALLED_APPS = [
    'django.contrib.admin',
    'django.contrib.auth',
    'django.contrib.contenttypes',
    'django.contrib.sessions',
    'django.contrib.messages',
    'django.contrib.staticfiles',
    'myapp',  # Add this line
]

Create a View

In your app directory (myapp), open the views.py file and add the following function:

from django.http import HttpResponse

def home(request):
    return HttpResponse("Hello, world. This is my first Django app.")

Set Up URLs

In your app directory, create a file named urls.py and add the following code:

from django.urls import path
from . import views

urlpatterns = [
    path('', views.home, name='home'),
]

from django.contrib import admin
from django.urls import include, path

urlpatterns = [
    path('admin/', admin.site.urls),
    path('', include('myapp.urls')),  # Include this line
]

python manage.py runserver 8080

pip install django

django-admin startproject myproject

python manage.py migrate

python manage.py createsuperuser

References
https://stackoverflow.com/questions/39696310/django-contrib-admin-default-admin-and-password