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drf fbv

Django has two types of views;

  • function-based views (FBVs), &
  • class-based views (CBVs)

Django originally started out with only FBVs, but then added CBVs as a way to templatize functionality so that you didn’t have to write boilerplate (i.e. the same code) code over and over again.

Function-based views (FBVs)

FBVs code here:

Todo App (using FBVs)

Let's look at how a simple todo application that allows CRUD operations would be written using only FBVs.

# todo/views.py

from django.shortcuts import render, get_object_or_404, redirect

from .forms import TaskForm, ConfirmForm
from .models import Task


def task_list_view(request):
    return render(request, 'todo/task_list.html', {
        'tasks': Task.objects.all(),
    })


def task_create_view(request):
    if request.method == 'POST':
        form = TaskForm(data=request.POST)
        if form.is_valid():
            form.save()
            return HttpResponseRedirect(reverse('task-list'))

    return render(request, 'todo/task_create.html', {
        'form': TaskForm(),
    })


def task_detail_view(request, pk):
    task = get_object_or_404(Task, pk=pk)
    return render(request, 'todo/task_detail.html', {
        'task': task,
    })


def task_update_view(request, pk):
    task = get_object_or_404(Task, pk=pk)

    if request.method == 'POST':
        form = TaskForm(instance=task, data=request.POST)
        if form.is_valid():
            form.save()
            return HttpResponseRedirect(reverse('task-detail', args={pk: pk}))

    return render(request, 'todo/task_update.html', {
        'task': task,
        'form': TaskForm(instance=task),
    })


def task_delete_view(request, pk):
    task = get_object_or_404(Task, pk=pk)

    if request.method == 'POST':
        form = ConfirmForm(data=request.POST)
        if form.is_valid():
            task.delete()
            return HttpResponseRedirect(reverse('task-list'))

    return render(request, 'todo/task_delete.html', {
        'task': task,
        'form': ConfirmForm(),
    })

You can get the full source code on GitHub.

Class-based views (CBVs)

CBVs code here:

django-cbv-flow

Todo App (using CBVs)

Now, let's rewrite our todo application to only use CBVs:

# todo/views.py

from django.shortcuts import render, get_object_or_404, redirect
from django.views import View

from .forms import TaskForm, ConfirmForm
from .models import Task


class TaskListView(View):

    def get(self, request, *args, **kwargs):
        return render(request, 'todo/task_list.html', {
            'tasks': Task.objects.all(),
        })


class TaskCreateView(View):

    def get(self, request, *args, **kwargs):
        return render(request, 'todo/task_create.html', {
            'form': TaskForm(),
        })

    def post(self, request, *args, **kwargs):
        form = TaskForm(data=request.POST)
        if form.is_valid():
            task = form.save()
            return redirect('task-detail', pk=task.pk)

        return self.get(request)


class TaskDetailView(View):

    def get(self, request, pk, *args, **kwargs):
        task = get_object_or_404(Task, pk=pk)

        return render(request, 'todo/task_detail.html', {
            'task': task,
        })


class TaskUpdateView(View):

    def get(self, request, pk, *args, **kwargs):
        task = get_object_or_404(Task, pk=pk)
        return render(request, 'todo/task_update.html', {
            'task': task,
            'form': TaskForm(instance=task),
        })

    def post(self, request, pk, *args, **kwargs):
        task = get_object_or_404(Task, pk=pk)
        form = TaskForm(instance=task, data=request.POST)
        if form.is_valid():
            form.save()
            return redirect('task-detail', pk=task.pk)

        return self.get(request, pk)


class TaskDeleteView(View):

    def get(self, request, pk, *args, **kwargs):
        task = get_object_or_404(Task, pk=pk)
        return render(request, 'todo/task_confirm_delete.html', {
            'task': task,
            'form': ConfirmForm(),
        })

    def post(self, request, pk, *args, **kwargs):
        task = get_object_or_404(Task, pk=pk)
        form = ConfirmForm(data=request.POST)
        if form.is_valid():
            task.delete()
            return redirect('task-list')

        return self.get(request, pk)

Also, let's not forget to make our urls.py call as_view():

# todo/urls.py

from django.urls import path

from .views import TaskListView, TaskDetailView, TaskCreateView, TaskUpdateView, TaskDeleteView


urlpatterns = [
    path('', TaskListView.as_view(), name='task-list'),
    path('create/', TaskCreateView.as_view(), name='task-create'),
    path('<int:pk>/', TaskDetailView.as_view(), name='task-detail'),
    path('update/<int:pk>/', TaskUpdateView.as_view(), name='task-update'),
    path('delete/<int:pk>/', TaskDeleteView.as_view(), name='task-delete'),
]

You can get the full source code on Github

Django's Generic CBVs

Django's generic CBVs are great for solving common problems like retrieving, creating, modifying, and deleting objects as well as pagination and archive views. They speed up the development process too.

from django.views.generic import CreateView


class TaskCreateView(CreateView):
    model = Task
    context_object_name = 'task'
    fields = ('name', 'description', 'is_done')
    template_name = 'todo/task_create.html'

Django's Built-in CBV Types

Reference