Views and URLs

urls.py routes to views

A view receives an HttpRequest and returns an HttpResponse; JsonResponse serialises dictionaries for APIs. URL patterns map paths (with converters such as <int:pk>) to views and get names for reverse(). Helpers like get_object_or_404 and decorators like require_GET reduce boilerplate. For larger APIs, Django REST Framework or Django Ninja add serializers, validation, authentication and OpenAPI docs.

Requests in, validated data out

Views and URLs serve requests, forms validate input, and transactions keep data consistent.

The catalog views and URLs

I ran this with Django 6.1.1 and Python 3.12 in a demo project (shopsite with a catalog app) using SQLite. A filtered list view using select_related and a detail view returning 404 for missing products; URL names are used by the tests.

from django.http import JsonResponse
from django.shortcuts import get_object_or_404
from django.views.decorators.http import require_GET

from .models import Product


@require_GET
def product_list(request):
    max_price = request.GET.get("max_price")
    qs = Product.objects.select_related("category").filter(in_stock=True)
    if max_price:
        qs = qs.filter(price__lte=max_price)
    data = [{"name": p.name, "price": str(p.price), "category": p.category.name} for p in qs]
    return JsonResponse({"count": len(data), "results": data})


@require_GET
def product_detail(request, pk):
    p = get_object_or_404(Product, pk=pk)
    return JsonResponse({"id": p.pk, "name": p.name, "price": str(p.price)})

# catalog/urls.py
from django.urls import path

from . import views

urlpatterns = [
    path("products/", views.product_list, name="product-list"),
    path("products/<int:pk>/", views.product_detail, name="product-detail"),
]

Name every URL

Named URLs let code and tests use reverse() instead of hard-coded paths.

Quick check: What does get_object_or_404 do when the object is missing?

• Raises Http404, producing a 404 response
• Returns None
• Creates the object
• Returns status 500