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Fixed #15906 - Documented HEAD method in CBVs; thanks zsiciarz for th…

…e patch.
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commit 518c58296667ffc36f90b873eb97aa99fa00eb1e 1 parent 72ca530
@timgraham timgraham authored
View
5 docs/ref/class-based-views/base.txt
@@ -71,6 +71,11 @@ View
delegated to :meth:`~View.get()`, a ``POST`` to :meth:`~View.post()`,
and so on.
+ By default, a ``HEAD`` request will be delegated to :meth:`~View.get()`.
+ If you need to handle ``HEAD`` requests in a different way than ``GET``,
+ you can override the :meth:`~View.head()` method. See
+ :ref:`supporting-other-http-methods` for an example.
+
The default implementation also sets ``request``, ``args`` and
``kwargs`` as instance variables, so any method on the view can know
the full details of the request that was made to invoke the view.
View
44 docs/topics/class-based-views/index.txt
@@ -84,6 +84,50 @@ function-like entry to class-based views::
For more information on how to use the built in generic views, consult the next
topic on :doc:`generic class based views</topics/class-based-views/generic-display>`.
+.. _supporting-other-http-methods:
+
+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.conf.urls import patterns
+ from books.views import BookListView
+
+ urlpatterns = patterns('',
+ (r'^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.
+
Decorating class-based views
============================

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