Fixed #20249 - Removed a "feature" in the tutorial that doesn't actually work.

Thanks bmispelon for the report and draft patch.
This commit is contained in:
Tim Graham 2013-05-11 19:08:57 -04:00
parent a6edde3260
commit 679a2ac843
2 changed files with 77 additions and 70 deletions

View file

@ -378,45 +378,40 @@ Improving our view
The list of polls shows polls that aren't published yet (i.e. those that have a
``pub_date`` in the future). Let's fix that.
In :doc:`Tutorial 4 </intro/tutorial04>` we deleted the view functions from
``views.py`` in favor of a :class:`~django.views.generic.list.ListView` in
``urls.py``::
In :doc:`Tutorial 4 </intro/tutorial04>` we introduced a class-based view,
based on :class:`~django.views.generic.list.ListView`::
url(r'^$',
ListView.as_view(
queryset=Poll.objects.order_by('-pub_date')[:5],
context_object_name='latest_poll_list',
template_name='polls/index.html'),
name='index'),
class IndexView(generic.ListView):
template_name = 'polls/index.html'
context_object_name = 'latest_poll_list'
def get_queryset(self):
"""Return the last five published polls."""
return Poll.objects.order_by('-pub_date')[:5]
``response.context_data['latest_poll_list']`` extracts the data this view
places into the context.
We need to amend the line that gives us the ``queryset``::
queryset=Poll.objects.order_by('-pub_date')[:5],
Let's change the queryset so that it also checks the date by comparing it with
``timezone.now()``. First we need to add an import::
We need to amend the ``get_queryset`` method and change it so that it also
checks the date by comparing it with ``timezone.now()``. First we need to add
an import::
from django.utils import timezone
and then we must amend the existing ``url`` function to::
and then we must amend the ``get_queryset`` method like so::
url(r'^$',
ListView.as_view(
queryset=Poll.objects.filter(pub_date__lte=timezone.now) \
.order_by('-pub_date')[:5],
context_object_name='latest_poll_list',
template_name='polls/index.html'),
name='index'),
def get_queryset(self):
"""
Return the last five published polls (not including those set to be
published in the future).
"""
return Poll.objects.filter(
pub_date__lte=timezone.now()
).order_by('-pub_date')[:5]
``Poll.objects.filter(pub_date__lte=timezone.now)`` returns a queryset
``Poll.objects.filter(pub_date__lte=timezone.now())`` returns a queryset
containing Polls whose ``pub_date`` is less than or equal to - that is, earlier
than or equal to - ``timezone.now``. Notice that we use a callable queryset
argument, ``timezone.now``, which will be evaluated at request time. If we had
included the parentheses, ``timezone.now()`` would be evaluated just once when
the web server is started.
than or equal to - ``timezone.now``.
Testing our new view
--------------------
@ -527,20 +522,18 @@ Testing the ``DetailView``
What we have works well; however, even though future polls don't appear in the
*index*, users can still reach them if they know or guess the right URL. So we
need similar constraints in the ``DetailViews``, by adding::
need to add a similar constraint to ``DetailView``::
queryset=Poll.objects.filter(pub_date__lte=timezone.now)
to them - for example::
class DetailView(generic.DetailView):
...
def get_queryset(self):
"""
Excludes any polls that aren't published yet.
"""
return Poll.objects.filter(pub_date__lte=timezone.now())
url(r'^(?P<pk>\d+)/$',
DetailView.as_view(
queryset=Poll.objects.filter(pub_date__lte=timezone.now),
model=Poll,
template_name='polls/detail.html'),
name='detail'),
and of course, we will add some tests, to check that a ``Poll`` whose
And of course, we will add some tests, to check that a ``Poll`` whose
``pub_date`` is in the past can be displayed, and that one with a ``pub_date``
in the future is not::
@ -566,9 +559,9 @@ in the future is not::
Ideas for more tests
--------------------
We ought to add similar ``queryset`` arguments to the other ``DetailView``
URLs, and create a new test class for each view. They'll be very similar to
what we have just created; in fact there will be a lot of repetition.
We ought to add a similar ``get_queryset`` method to ``ResultsView`` and
create a new test class for that view. It'll be very similar to what we have
just created; in fact there will be a lot of repetition.
We could also improve our application in other ways, adding tests along the
way. For example, it's silly that ``Polls`` can be published on the site that