Code-Memo

Function-Based Views (FBVs)

Function-Based Views (FBVs) in Django are one of the simplest and most straightforward ways to handle requests and responses. Each view is defined as a Python function that receives a web request and returns a web response.

Basic Structure of a Function-Based View

A basic function-based view receives a HttpRequest object as its first parameter and returns an HttpResponse object.

Simple Function-Based View

from django.http import HttpResponse

def hello_world(request):
    return HttpResponse("Hello, world!")

• hello_world is a function that takes a request and returns a simple HttpResponse.

You can also create a view that returns a JsonResponse:

from django.http import JsonResponse

def hello_world(request):
    return JsonResponse({'message': 'Hello World!'})

urls.py would be

from django.urls import path
from . import views

urlpatterns = [
    path('hello/', views.hello_world, name='hello_world'),
]

Using URL Parameters in FBVs

FBVs can capture URL parameters and use them in the view function.

from django.http import HttpResponse

def greet(request, name):
    return HttpResponse(f"Hello, {name}!")

• The name parameter is captured from the URL and used in the response.

Here the url would be

path('greet/<str:name>/', views.greet, name='greet')

Handling 404 Errors in FBVs

You can raise a Http404 exception to handle not found errors.

from django.http import Http404

def get_item(request, item_id):
    try:
        item = Item.objects.get(pk=item_id)
    except Item.DoesNotExist:
        raise Http404("Item does not exist")
    return render(request, 'item_detail.html', {'item': item})

• The view raises a Http404 exception if the Item does not exist.