Class-based views

request を受け取り、response. を返すビューは、呼び出し可能です。Djangoは、ビューを関数としてのみではなく、いくつかのクラスの例を提供します。これらのクラスはあなたがビューを構造化し、継承とミックスインを利用して、コードを再利用することを可能にします。後に行うことになる単純な作業のための汎用ビューもいくつかありますが、ユースケースに合った再利用可能なビューの構造を設計したいですよね。完全な詳細に関しては class-based views reference documentation を参照してください。

Basic examples

Django provides base view classes which will suit a wide range of applications. All views inherit from the View class, which handles linking the view in to the URLs, HTTP method dispatching and other simple features. RedirectView is for a simple HTTP redirect, and TemplateView extends the base class to make it also render a template.

Simple usage in your URLconf

The simplest way to use generic views is to create them directly in your URLconf. If you're only changing a few simple attributes on a class-based view, you can simply pass them into the as_view() method call itself:

from django.urls import path
from django.views.generic import TemplateView

urlpatterns = [
    path('about/', TemplateView.as_view(template_name="about.html")),

Any arguments passed to as_view() will override attributes set on the class. In this example, we set template_name on the TemplateView. A similar overriding pattern can be used for the url attribute on RedirectView.

Subclassing generic views

The second, more powerful way to use generic views is to inherit from an existing view and override attributes (such as the template_name) or methods (such as get_context_data) in your subclass to provide new values or methods. Consider, for example, a view that just displays one template, about.html. Django has a generic view to do this - TemplateView - so we can just subclass it, and override the template name:

# some_app/
from django.views.generic import TemplateView

class AboutView(TemplateView):
    template_name = "about.html"

Then we just need to add this new view into our URLconf. TemplateView is a class, not a function, so we point the URL to the as_view() class method instead, which provides a function-like entry to class-based views:

from django.urls import path
from some_app.views import AboutView

urlpatterns = [
    path('about/', AboutView.as_view()),

For more information on how to use the built in generic views, consult the next topic on generic class-based views.

Supporting other HTTP methods

Suppose somebody wants to access our book library over HTTP using the views as an API. The API client would connect every now and then and download book data for the books published since last visit. But if no new books appeared since then, it is a waste of CPU time and bandwidth to fetch the books from the database, render a full response and send it to the client. It might be preferable to ask the API when the most recent book was published.

We map the URL to book list view in the URLconf:

from django.urls import path
from books.views import BookListView

urlpatterns = [
    path('books/', BookListView.as_view()),

And the view:

from django.http import HttpResponse
from django.views.generic import ListView
from books.models import Book

class BookListView(ListView):
    model = Book

    def head(self, *args, **kwargs):
        last_book = self.get_queryset().latest('publication_date')
        response = HttpResponse('')
        # RFC 1123 date format
        response['Last-Modified'] = last_book.publication_date.strftime('%a, %d %b %Y %H:%M:%S GMT')
        return response

If the view is accessed from a GET request, a plain-and-simple object list is returned in the response (using book_list.html template). But if the client issues a HEAD request, the response has an empty body and the Last-Modified header indicates when the most recent book was published. Based on this information, the client may or may not download the full object list.

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