Tampilan berdasarkan-kelas¶
A view is a callable which takes a request and returns a response. This can be more than just a function, and Django provides an example of some classes which can be used as views. These allow you to structure your views and reuse code by harnessing inheritance and mixins. There are also some generic views for tasks which we'll get to later, but you may want to design your own structure of reusable views which suits your use case. For full details, see the class-based views reference documentation.
Contoh dasar¶
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 into the URLs, HTTP method dispatching and other
common features. RedirectView provides a
HTTP redirect, and TemplateView extends the
base class to make it also render a template.
Penggunaan dalam URLconf anda¶
The most direct way to use generic views is to create them directly in your
URLconf. If you're only changing a few attributes on a class-based view, you
can 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")),
]
Apapun argumen dilewatkan ke as_view() akan menimpa atribut disetel pada kelas. Dalam contoh ini, kami menyetel template_name` pada TemplateView. Pola penibanan mirip dapat digunakan untuk atribut url pada RedirectView.
Mensubkelaskan tampilan umum¶
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 subclass it, and
override the template name:
# some_app/views.py
from django.views.generic import TemplateView
class AboutView(TemplateView):
template_name = "about.html"
Then we 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:
# urls.py
from django.urls import path
from some_app.views import AboutView
urlpatterns = [
path('about/', AboutView.as_view()),
]
Untuk informasi lebih pada bagaimana menggunakan tampilan umum siap pakai, obrolkan topik selanjutnya di generic class-based views.
mendukung cara HTTP lain¶
Misalkan seseorang ingin mengakses pustaka buku kami terhadap HTTP menggunakan tampilan sebagai sebuah klien API akan terhubung setiap sekarang kemudian dan mengunduh buku untuk buku diterbitkan sejak kunjugan terakhir. Tetapi jika tidak ada buku baru muncul sejak itu, itu adalah pembuangan dari waktu CPU dan lebar pita untuk mengambil buku-buku dari basisdata, mengirim tanggapan penuh dan mengirim itu ke klien. Itu mungkin lebih baik untuk menanyakan API ketika kebanyakan buku saat ini telah diterbitkan.
Kami memetakan UTL pada tampilan daftar buku di URLconf:
from django.urls import path
from books.views import BookListView
urlpatterns = [
path('books/', BookListView.as_view()),
]
Dan tampilan:
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, an object list is returned in
the response (using the 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.
