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Gopal Ghate
Gopal Ghate

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🧱 Django Class-Based Views (CBVs) – Building APIs for the Frontend

#django #backend #api #webdev

In this article, we’ll explore how Class-Based Views (CBVs) can be used to build clean, reusable APIs instead of rendering templates.

💡 What Are Class-Based Views?

Class-Based Views (CBVs) allow you to organize request-handling logic using Python classes instead of functions. They provide structure and reusability for common API operations such as fetching lists, retrieving single records, creating, updating, and deleting data.

Example – converting FBV to CBV:
Function Based View

from django.http import JsonResponse

def home(request):
    return JsonResponse({"message" : Welcome to My Blog API"})
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Class Based view

from django.views import View
from django.http import JsonResponse

class HomeView(View):
    def get(self, request):
        return JsonResponse({"message": "Welcome to My Blog API!"})
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And in urls.py

from django.urls import path
from .views import HomeView


urlpatterns = [
    path('', HomeView.as_view(), name='home'),
]
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as_view() converts the class into a callable function that Django can handle.

⚙️ Example: API CRUD Using CBVs

Let's say we have a simple Post models:

from django.db import models

class Post(models.Model):
    title = models.CharField(max_length=200)
    content = models.TextField()
    created_at = models.DateTimeField(auto_now_add=True)

def __str__(self):
    return self.title
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We’ll create CBVs for each CRUD operation and return JSON responses.

1️⃣ ListView – Get All Posts 

class PostListView(View):
    def get(self, request):
        posts = list(Post.objects.values())
        return JsonResponse({"posts": posts})
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2️⃣ DetailView – Get a Single Post 

class PostDetailView(View):
    def get(self, request, pk):
        try:
            post = Post.objects.values().get(id=pk)
            return JsonResponse({"post": post})
        except Post.DoesNotExist:
            return HttpResponseNotFound(JsonResponse({"error": "Post not found"}))
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3️⃣ CreateView – Add a New Post

@method_decorator(csrf_exempt, name='dispatch')
class PostCreateView(View):
    def post(self, request):
        data = json.loads(request.body)
        post = Post.objects.create(title=data.get('title'), content=data.get('content'))
        return JsonResponse({"id": post.id, "message": "Post created successfully"}, status=201)
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4️⃣ UpdateView – Edit an Existing Post


@method_decorator(csrf_exempt, name='dispatch')
class PostUpdateView(View):
    def put(self, request, pk):
        try:
            post = Post.objects.get(id=pk)
            data = json.loads(request.body)
            post.title = data.get('title', post.title)
            post.content = data.get('content', post.content)
            post.save()
            return JsonResponse({"message": "Post updated successfully"})
        except Post.DoesNotExist:
            return JsonResponse({"error": "Post not found"}, status=404)
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5️⃣ DeleteView – Remove a Post 


@method_decorator(csrf_exempt, name='dispatch')
class PostDeleteView(View):
    def delete(self, request, pk):
        try:
            post = Post.objects.get(id=pk)
            post.delete()
            return JsonResponse({"message": "Post deleted successfully"})
        except Post.DoesNotExist:
            return JsonResponse({"error": "Post not found"}, status=404)
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🧠 Why CBVs Are Great for APIs

  • Cleaner, more structured code.
  • Each HTTP method has its own function (get, post, put, delete).
  • Easy to extend and reuse logic using inheritance.
  • Plays nicely with Django REST Framework if you decide to scale up.

⚡ Best Practices

  • Always return JSON for frontend consumption.

  • Use csrf_exempt carefully or rely on proper CSRF tokens for POST/PUT requests.

  • Validate input data before saving.

  • Use Django REST Framework for complex APIs with authentication, pagination, and serializers.

🏆 Summary

  • CBVs can be used not only for HTML rendering but also for clean API design.

  • Each request type (GET, POST, PUT, DELETE) can be handled within a single class.

  • Use CBVs for modular, maintainable, and testable backend APIs.

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