From 13de270bd52d057584023de08ea869722a7e5d5a Mon Sep 17 00:00:00 2001 From: Tim Graham Date: Sat, 11 May 2013 19:08:57 -0400 Subject: [PATCH] [1.5.X] Fixed #20249 - Removed a "feature" in the tutorial that doesn't actually work. Thanks bmispelon for the report and draft patch. Backport of 679a2ac843 from master --- docs/intro/tutorial04.txt | 70 +++++++++++++++++++++-------------- docs/intro/tutorial05.txt | 77 ++++++++++++++++++--------------------- 2 files changed, 77 insertions(+), 70 deletions(-) diff --git a/docs/intro/tutorial04.txt b/docs/intro/tutorial04.txt index 87d8e584ad7..9f54243a3e6 100644 --- a/docs/intro/tutorial04.txt +++ b/docs/intro/tutorial04.txt @@ -185,7 +185,7 @@ conversion. We will: 2. Delete some of the old, unneeded views. -3. Fix up URL handling for the new views. +3. Introduce new views based on Django's generic views. Read on for details. @@ -205,32 +205,51 @@ Amend URLconf First, open the ``polls/urls.py`` URLconf and change it like so:: from django.conf.urls import patterns, url - from django.views.generic import DetailView, ListView - from polls.models import Poll + + from polls import views urlpatterns = patterns('', - url(r'^$', - ListView.as_view( - queryset=Poll.objects.order_by('-pub_date')[:5], - context_object_name='latest_poll_list', - template_name='polls/index.html'), - name='index'), - url(r'^(?P\d+)/$', - DetailView.as_view( - model=Poll, - template_name='polls/detail.html'), - name='detail'), - url(r'^(?P\d+)/results/$', - DetailView.as_view( - model=Poll, - template_name='polls/results.html'), - name='results'), - url(r'^(?P\d+)/vote/$', 'polls.views.vote', name='vote'), + url(r'^$', views.IndexView.as_view(), name='index'), + url(r'^(?P\d+)/$', views.DetailView.as_view(), name='detail'), + url(r'^(?P\d+)/results/$', views.ResultsView.as_view(), name='results'), + url(r'^(?P\d+)/vote/$', views.vote, name='vote'), ) Amend views ----------- +Next, we're going to remove our old ``index``, ``detail``, and ``results`` +views and use Django's generic views instead. To do so, open the +``polls/views.py`` file and change it like so:: + + from django.shortcuts import get_object_or_404, render + from django.http import HttpResponseRedirect + from django.core.urlresolvers import reverse + from django.views import generic + + from polls.models import Choice, Poll + + 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] + + + class DetailView(generic.DetailView): + model = Poll + template_name = 'polls/detail.html' + + + class ResultsView(generic.DetailView): + model = Poll + template_name = 'polls/results.html' + + def vote(request, poll_id): + .... + We're using two generic views here: :class:`~django.views.generic.list.ListView` and :class:`~django.views.generic.detail.DetailView`. Respectively, those @@ -238,7 +257,7 @@ two views abstract the concepts of "display a list of objects" and "display a detail page for a particular type of object." * Each generic view needs to know what model it will be acting - upon. This is provided using the ``model`` parameter. + upon. This is provided using the ``model`` attribute. * The :class:`~django.views.generic.detail.DetailView` generic view expects the primary key value captured from the URL to be called @@ -248,7 +267,7 @@ two views abstract the concepts of "display a list of objects" and By default, the :class:`~django.views.generic.detail.DetailView` generic view uses a template called ``/_detail.html``. In our case, it'll use the template ``"polls/poll_detail.html"``. The -``template_name`` argument is used to tell Django to use a specific +``template_name`` attribute is used to tell Django to use a specific template name instead of the autogenerated default template name. We also specify the ``template_name`` for the ``results`` list view -- this ensures that the results view and the detail view have a @@ -268,16 +287,11 @@ automatically -- since we're using a Django model (``Poll``), Django is able to determine an appropriate name for the context variable. However, for ListView, the automatically generated context variable is ``poll_list``. To override this we provide the ``context_object_name`` -option, specifying that we want to use ``latest_poll_list`` instead. +attribute, specifying that we want to use ``latest_poll_list`` instead. As an alternative approach, you could change your templates to match the new default context variables -- but it's a lot easier to just tell Django to use the variable you want. -You can now delete the ``index()``, ``detail()`` and ``results()`` views from -``polls/views.py``. We don't need them anymore -- they have been replaced by -generic views. You can also delete the import for ``HttpResponse``, which is no -longer required. - Run the server, and use your new polling app based on generic views. For full details on generic views, see the :doc:`generic views documentation diff --git a/docs/intro/tutorial05.txt b/docs/intro/tutorial05.txt index 5229856f080..60a8996ec49 100644 --- a/docs/intro/tutorial05.txt +++ b/docs/intro/tutorial05.txt @@ -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 ` 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 ` 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\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