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Fixed #6735 -- Added class-based views.

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This patch is the result of the work of many people, over many years.
To try and thank individuals would inevitably lead to many people
being left out or forgotten -- so rather than try to give a list that
will inevitably be incomplete, I'd like to thank *everybody* who
contributed in any way, big or small, with coding, testing, feedback
and/or documentation over the multi-year process of getting this into
trunk.

git-svn-id: http://code.djangoproject.com/svn/django/trunk@14254 bcc190cf-cafb-0310-a4f2-bffc1f526a37
This commit is contained in:
Russell Keith-Magee
2010-10-18 13:34:47 +00:00
parent fa2159f85b
commit 0fcb094557
55 changed files with 5020 additions and 74 deletions
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6
docs/index.txt
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@@ -103,8 +103,8 @@ The view layer
:doc:`Custom storage <howto/custom-file-storage>`
* **Generic views:**
:doc:`Overview<topics/generic-views>` |
:doc:`Built-in generic views<ref/generic-views>`
:doc:`Overview<topics/class-based-views>` |
:doc:`Built-in generic views<ref/class-based-views>`
* **Advanced:**
:doc:`Generating CSV <howto/outputting-csv>` |
@@ -189,6 +189,8 @@ Other batteries included
* :doc:`Unicode in Django <ref/unicode>`
* :doc:`Web design helpers <ref/contrib/webdesign>`
* :doc:`Validators <ref/validators>`
* Function-based generic views (Deprecated) :doc:`Overview<topics/generic-views>` | :doc:`Built-in generic views<ref/generic-views>` | :doc:`Migration guide<topics/generic-views-migration>`
The Django open-source project
==============================

9
docs/internals/deprecation.txt
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@@ -118,6 +118,15 @@ their deprecation, as per the :ref:`Django deprecation policy
:func:`django.contrib.formtools.utils.security_hash`
is deprecated, in favour of :func:`django.contrib.formtools.utils.form_hmac`
* The function-based generic views have been deprecated in
favor of their class-based cousins. The following modules
will be removed:
* :mod:`django.views.generic.create_update`
* :mod:`django.views.generic.date_based`
* :mod:`django.views.generic.list_detail`
* :mod:`django.views.generic.simple`
* 2.0
* ``django.views.defaults.shortcut()``. This function has been moved
to ``django.contrib.contenttypes.views.shortcut()`` as part of the

140
docs/intro/tutorial04.txt
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@@ -232,6 +232,7 @@ tutorial so far::
Change it like so::
from django.conf.urls.defaults import *
from django.views.generic import DetailView, ListView
from polls.models import Poll
info_dict = {
@@ -239,88 +240,91 @@ Change it like so::
}
urlpatterns = patterns('',
(r'^$', 'django.views.generic.list_detail.object_list', info_dict),
(r'^(?P<object_id>\d+)/$', 'django.views.generic.list_detail.object_detail', info_dict),
url(r'^(?P<object_id>\d+)/results/$', 'django.views.generic.list_detail.object_detail', dict(info_dict, template_name='polls/results.html'), 'poll_results'),
(r'^$',
ListView.as_view(
models=Poll,
context_object_name='latest_poll_list'
template_name='polls/index.html')),
(r'^(?P<pk>\d+)/$',
DetailView.as_view(
models=Poll,
template_name='polls/detail.html')),
url(r'^(?P<pk>\d+)/results/$',
DetailView.as_view(
models=Poll,
template_name='polls/results.html'),
'poll_results'),
(r'^(?P<poll_id>\d+)/vote/$', 'polls.views.vote'),
)
We're using two generic views here:
:func:`~django.views.generic.list_detail.object_list` and
:func:`~django.views.generic.list_detail.object_detail`. Respectively, those two
views abstract the concepts of "display a list of objects" and "display a detail
page for a particular type of object."
:class:`~django.views.generic.list.ListView` and
:class:`~django.views.generic.detail.DetailView`. Respectively, those
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 data it will be acting upon. This
data is provided in a dictionary. The ``queryset`` key in this dictionary
points to the list of objects to be manipulated by the generic view.
* Each generic view needs to know what model it will be acting
upon. This is provided using the ``model`` parameter.
* The :func:`~django.views.generic.list_detail.object_detail` generic view
expects the ID value captured from the URL to be called ``"object_id"``,
so we've changed ``poll_id`` to ``object_id`` for the generic views.
* The :class:`~django.views.generic.list.DetailView` generic view
expects the primary key value captured from the URL to be called
``"pk"``, so we've changed ``poll_id`` to ``pk`` for the generic
views.
* We've added a name, ``poll_results``, to the results view so that we have
a way to refer to its URL later on (see the documentation about
:ref:`naming URL patterns <naming-url-patterns>` for information). We're
also using the :func:`~django.conf.urls.default.url` function from
* We've added a name, ``poll_results``, to the results view so
that we have a way to refer to its URL later on (see the
documentation about :ref:`naming URL patterns
<naming-url-patterns>` for information). We're also using the
:func:`~django.conf.urls.default.url` function from
:mod:`django.conf.urls.defaults` here. It's a good habit to use
:func:`~django.conf.urls.defaults.url` when you are providing a pattern
name like this.
:func:`~django.conf.urls.defaults.url` when you are providing a
pattern name like this.
By default, the :func:`~django.views.generic.list_detail.object_detail` generic
view uses a template called ``<app name>/<model name>_detail.html``. In our
case, it'll use the template ``"polls/poll_detail.html"``. Thus, rename your
``polls/detail.html`` template to ``polls/poll_detail.html``, and change the
:func:`~django.shortcuts.render_to_response` line in ``vote()``.
By default, the :class:`~django.views.generic.list.DetailView` generic
view uses a template called ``<app name>/<model name>_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 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
different appearance when rendered, even though they're both a
:class:`~django.views.generic.list.DetailView` behind the scenes.
Similarly, the :func:`~django.views.generic.list_detail.object_list` generic
view uses a template called ``<app name>/<model name>_list.html``. Thus, rename
``polls/index.html`` to ``polls/poll_list.html``.
Similarly, the :class:`~django.views.generic.list.ListView` generic
view uses a default template called ``<app name>/<model
name>_list.html``; we use ``template_name`` to tell
:class:`~django.views.generic.list.ListView` to use our existing
``"polls/index.html"`` template.
Because we have more than one entry in the URLconf that uses
:func:`~django.views.generic.list_detail.object_detail` for the polls app, we
manually specify a template name for the results view:
``template_name='polls/results.html'``. Otherwise, both views would use the same
template. Note that we use ``dict()`` to return an altered dictionary in place.
In previous parts of the tutorial, the templates have been provided
with a context that contains the ``poll`` and ``latest_poll_list``
context variables. For DetailView the ``poll`` variable is provided
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.
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.
.. note:: :meth:`django.db.models.QuerySet.all` is lazy
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.
It might look a little frightening to see ``Poll.objects.all()`` being used
in a detail view which only needs one ``Poll`` object, but don't worry;
``Poll.objects.all()`` is actually a special object called a
:class:`~django.db.models.QuerySet`, which is "lazy" and doesn't hit your
database until it absolutely has to. By the time the database query happens,
the :func:`~django.views.generic.list_detail.object_detail` generic view
will have narrowed its scope down to a single object, so the eventual query
will only select one row from the database.
The ``vote()`` view is still required. However, it must be modified to
match the new context variables. In the
:func:`~django.shortcuts.render_to_response` call, rename the ``poll``
context variable to ``object``.
If you'd like to know more about how that works, The Django database API
documentation :ref:`explains the lazy nature of QuerySet objects
<querysets-are-lazy>`.
In previous parts of the tutorial, the templates have been provided with a
context that contains the ``poll`` and ``latest_poll_list`` context variables.
However, the generic views provide the variables ``object`` and ``object_list``
as context. Therefore, you need to change your templates to match the new
context variables. Go through your templates, and modify any reference to
``latest_poll_list`` to ``object_list``, and change any reference to ``poll``
to ``object``.
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.
The ``vote()`` view is still required. However, it must be modified to match the
new context variables. In the :func:`~django.shortcuts.render_to_response` call,
rename the ``poll`` context variable to ``object``.
The last thing to do is fix the URL handling to account for the use of generic
views. In the vote view above, we used the
:func:`~django.core.urlresolvers.reverse` function to avoid hard-coding our
URLs. Now that we've switched to a generic view, we'll need to change the
:func:`~django.core.urlresolvers.reverse` call to point back to our new generic
view. We can't simply use the view function anymore -- generic views can be (and
are) used multiple times -- but we can use the name we've given::
The last thing to do is fix the URL handling to account for the use of
generic views. In the vote view above, we used the
:func:`~django.core.urlresolvers.reverse` function to avoid
hard-coding our URLs. Now that we've switched to a generic view, we'll
need to change the :func:`~django.core.urlresolvers.reverse` call to
point back to our new generic view. We can't simply use the view
function anymore -- generic views can be (and are) used multiple times
-- but we can use the name we've given::
return HttpResponseRedirect(reverse('poll_results', args=(p.id,)))

1391
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2
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@@ -8,7 +8,7 @@ abstracted into "generic views" that let you quickly provide common views of
an object without actually needing to write any Python code.
A general introduction to generic views can be found in the :doc:`topic guide
</topics/http/generic-views>`.
</topics/generic-views>`.
This reference contains details of Django's built-in generic views, along with
a list of all keyword arguments that a generic view expects. Remember that

10
docs/ref/index.txt
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@@ -12,7 +12,7 @@ API Reference
exceptions
files/index
forms/index
generic-views
class-based-views
middleware
models/index
request-response
@@ -22,3 +22,11 @@ API Reference
unicode
utils
validators
Deprecated features
-------------------
.. toctree::
:maxdepth: 1
generic-views

29
docs/releases/1.3.txt
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@@ -17,6 +17,23 @@ upgrade path from Django 1.2.
What's new in Django 1.3
========================
Class-based views
~~~~~~~~~~~~~~~~~
Django 1.3 adds a framework that allows you to use a class as a view.
This means you can compose a view out of a collection of methods that
can be subclassed and overridden to provide
Analogs of all the old function-based generic views have been
provided, along with a completely generic view base class that can be
used as the basis for reusable applications that can be easily
extended.
See :doc:`the documentation on Generic Views</topics/generic-views>`
for more details. There is also a document to help you :doc:`convert
your function-based generic views to class-based
views</topics/generic-views-migration>`.
Logging
~~~~~~~
@@ -174,6 +191,18 @@ If you are currently using the ``mod_python`` request handler, it is strongly
encouraged you redeploy your Django instances using :doc:`mod_wsgi
</howto/deployment/modwsgi>`.
Function-based generic views
~~~~~~~~~~~~~~~~~~~~~~~~~~~~
As a result of the introduction of class-based generic views, the
function-based generic views provided by Django have been deprecated.
The following modules and the views they contain have been deprecated:
* :mod:`django.views.generic.create_update`
* :mod:`django.views.generic.date_based`
* :mod:`django.views.generic.list_detail`
* :mod:`django.views.generic.simple`
Test client response ``template`` attribute
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

535
docs/topics/class-based-views.txt Normal file
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@@ -0,0 +1,535 @@
=========================
Class-based generic views
=========================
.. versionadded:: 1.3
.. note::
Prior to Django 1.3, generic views were implemented as functions. The
function-based implementation has been deprecated in favor of the
class-based approach described here.
For the reference to the old on details on the old implementation,
see the :doc:`topic guide </topics/generic-views>` and
:doc:`detailed reference </topics/generic-views>`.
Writing Web applications can be monotonous, because we repeat certain patterns
again and again. Django tries to take away some of that monotony at the model
and template layers, but Web developers also experience this boredom at the view
level.
Django's *generic views* were developed to ease that pain. They take certain
common idioms and patterns found in view development and abstract them so that
you can quickly write common views of data without having to write too much
code.
We can recognize certain common tasks, like displaying a list of objects, and
write code that displays a list of *any* object. Then the model in question can
be passed as an extra argument to the URLconf.
Django ships with generic views to do the following:
* Perform common "simple" tasks: redirect to a different page and
render a given template.
* Display list and detail pages for a single object. If we were creating an
application to manage conferences then a ``TalkListView`` and a
``RegisteredUserListView`` would be examples of list views. A single
talk page is an example of what we call a "detail" view.
* Present date-based objects in year/month/day archive pages,
associated detail, and "latest" pages. The Django Weblog's
(http://www.djangoproject.com/weblog/) year, month, and
day archives are built with these, as would be a typical
newspaper's archives.
* Allow users to create, update, and delete objects -- with or
without authorization.
Taken together, these views provide easy interfaces to perform the most common
tasks developers encounter.
Simple usage
============
Class-based generic views (and indeed any class-based views that are
based on the base classes Django provides) can be configured in two
ways: subclassing, or passing in arguments directly in the URLconf.
When you subclass a class-based view, you can override attributes
(such as the template name, ``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 -
:class:`~django.views.generic.base.TemplateView` - so we can just
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 just need to add this new view into our URLconf. As the class-based
views themselves are classes, we point the URL to the as_view class method
instead, which is the entrypoint for class-based views::
# urls.py
from django.conf.urls.defaults import *
from some_app.views import AboutView
urlpatterns = patterns('',
(r'^about/', AboutView.as_view()),
)
Alternatively, if you're only changing a few simple attributes on a
class-based view, you can simply pass the new attributes into the as_view
method call itself::
from django.conf.urls.defaults import *
from django.views.generic import TemplateView
urlpatterns = patterns('',
(r'^about/', TemplateView.as_view(template_name="about.html")),
)
A similar overriding pattern can be used for the ``url`` attribute on
:class:`~django.views.generic.base.RedirectView`, another simple
generic view.
Generic views of objects
========================
:class:`~django.views.generic.base.TemplateView` certainly is useful,
but Django's generic views really shine when it comes to presenting
views on your database content. Because it's such a common task,
Django comes with a handful of built-in generic views that make
generating list and detail views of objects incredibly easy.
Let's take a look at one of these generic views: the "object list" view. We'll
be using these models::
# models.py
from django.db import models
class Publisher(models.Model):
name = models.CharField(max_length=30)
address = models.CharField(max_length=50)
city = models.CharField(max_length=60)
state_province = models.CharField(max_length=30)
country = models.CharField(max_length=50)
website = models.URLField()
def __unicode__(self):
return self.name
class Meta:
ordering = ["-name"]
class Book(models.Model):
title = models.CharField(max_length=100)
authors = models.ManyToManyField('Author')
publisher = models.ForeignKey(Publisher)
publication_date = models.DateField()
To build a list page of all publishers, we'd use a URLconf along these lines::
from django.conf.urls.defaults import *
from django.views.generic import ListView
from books.models import Publisher
urlpatterns = patterns('',
(r'^publishers/$', ListView.as_view(
model=Publisher,
)),
)
That's all the Python code we need to write. We still need to write a template,
however. We could explicitly tell the view which template to use
by including a ``template_name`` key in the arguments to as_view, but in
the absence of an explicit template Django will infer one from the object's
name. In this case, the inferred template will be
``"books/publisher_list.html"`` -- the "books" part comes from the name of the
app that defines the model, while the "publisher" bit is just the lowercased
version of the model's name.
.. highlightlang:: html+django
This template will be rendered against a context containing a variable called
``object_list`` that contains all the publisher objects. A very simple template
might look like the following::
{% extends "base.html" %}
{% block content %}
<h2>Publishers</h2>
<ul>
{% for publisher in object_list %}
<li>{{ publisher.name }}</li>
{% endfor %}
</ul>
{% endblock %}
That's really all there is to it. All the cool features of generic views come
from changing the "info" dictionary passed to the generic view. The
:doc:`generic views reference</ref/class-based-views>` documents all the generic
views and all their options in detail; the rest of this document will consider
some of the common ways you might customize and extend generic views.
Extending generic views
=======================
.. highlightlang:: python
There's no question that using generic views can speed up development
substantially. In most projects, however, there comes a moment when the
generic views no longer suffice. Indeed, the most common question asked by new
Django developers is how to make generic views handle a wider array of
situations.
This is one of the reasons generic views were redesigned for the 1.3 release -
previously, they were just view functions with a bewildering array of options;
now, rather than passing in a large amount of configuration in the URLconf,
the recommended way to extend generic views is to subclass them, and override
their attributes or methods.
Making "friendly" template contexts
-----------------------------------
You might have noticed that our sample publisher list template stores all the
books in a variable named ``object_list``. While this works just fine, it isn't
all that "friendly" to template authors: they have to "just know" that they're
dealing with publishers here. A better name for that variable would be
``publisher_list``; that variable's content is pretty obvious.
We can change the name of that variable easily with the ``context_object_name``
attribute - here, we'll override it in the URLconf, since it's a simple change:
.. parsed-literal::
urlpatterns = patterns('',
(r'^publishers/$', ListView.as_view(
model=Publisher,
**context_object_name = "publisher_list",**
)),
)
Providing a useful ``context_object_name`` is always a good idea. Your
coworkers who design templates will thank you.
Adding extra context
--------------------
Often you simply need to present some extra information beyond that
provided by the generic view. For example, think of showing a list of
all the books on each publisher detail page. The
:class:`~django.views.generic.detail.DetailView` generic view provides
the publisher to the context, but it seems there's no way to get
additional information in that template.
However, there is; you can subclass
:class:`~django.views.generic.detail.DetailView` and provide your own
implementation of the ``get_context_data`` method. The default
implementation of this that comes with
:class:`~django.views.generic.detail.DetailView` simply adds in the
object being displayed to the template, but we can override it to show
more::
from django.views.generic import DetailView
from some_app.models import Publisher, Book
class PublisherDetailView(DetailView):
context_object_name = "publisher"
model = Publisher
def get_context_data(self, **kwargs):
# Call the base implementation first to get a context
context = DetailView.get_context_data(self, **kwargs)
# Add in a QuerySet of all the books
context['book_list'] = Book.objects.all()
return context
Viewing subsets of objects
--------------------------
Now let's take a closer look at the ``model`` argument we've been
using all along. The ``model`` argument, which specifies the database
model that the view will operate upon, is available on all the
generic views that operate on a single object or a collection of
objects. However, the ``model`` argument is not the only way to
specify the objects that the view will operate upon -- you can also
specify the list of objects using the ``queryset`` argument::
from django.views.generic import DetailView
from some_app.models import Publisher, Book
class PublisherDetailView(DetailView):
context_object_name = "publisher"
queryset = Publisher.object.all()
Specifying ``mode = Publisher`` is really just shorthand for saying
``queryset = Publisher.objects.all()``. However, by using ``queryset``
to define a filtered list of objects you can be more specific about the
objects that will be visible in the view (see :doc:`/topics/db/queries`
for more information about ``QuerySet`` objects, and see the
:doc:`generic views reference</ref/generic-views>` for the complete details).
To pick a simple example, we might want to order a list of books by
publication date, with the most recent first::
urlpatterns = patterns('',
(r'^publishers/$', ListView.as_view(
queryset = Publisher.objects.all(),
context_object_name = "publisher_list",
)),
(r'^publishers/$', ListView.as_view(
queryset = Book.objects.order_by("-publication_date"),
context_object_name = "book_list",
)),
)
That's a pretty simple example, but it illustrates the idea nicely. Of course,
you'll usually want to do more than just reorder objects. If you want to
present a list of books by a particular publisher, you can use the same
technique (here, illustrated using subclassing rather than by passing arguments
in the URLconf)::
from django.views.generic import ListView
from some_app.models import Book
class AcmeBookListView(ListView):
context_object_name = "book_list"
queryset = Book.objects.filter(publisher__name="Acme Publishing")
template_name = "books/acme_list.html"
Notice that along with a filtered ``queryset``, we're also using a custom
template name. If we didn't, the generic view would use the same template as the
"vanilla" object list, which might not be what we want.
Also notice that this isn't a very elegant way of doing publisher-specific
books. If we want to add another publisher page, we'd need another handful of
lines in the URLconf, and more than a few publishers would get unreasonable.
We'll deal with this problem in the next section.
.. note::
If you get a 404 when requesting ``/books/acme/``, check to ensure you
actually have a Publisher with the name 'ACME Publishing'. Generic
views have an ``allow_empty`` parameter for this case. See the
:doc:`generic views reference</ref/class-based-views>` for more details.
Dynamic filtering
-----------------
Another common need is to filter down the objects given in a list page by some
key in the URL. Earlier we hard-coded the publisher's name in the URLconf, but
what if we wanted to write a view that displayed all the books by some arbitrary
publisher?
Handily, the ListView has a ``get_queryset`` method we can override. Previously,
it has just been returning the value of the ``queryset`` attribute, but now we
can add more logic.
The key part to making this work is that when class-based views are called,
various useful things are stored on ``self``; as well as the request
(``self.request``) this includes the positional (``self.args``) and name-based
(``self.kwargs``) arguments captured according to the URLconf.
Here, we have a URLconf with a single captured group::
from some_app.views import PublisherBookListView
urlpatterns = patterns('',
(r'^books/(\w+)/$', PublisherBookListView.as_view()),
)
Next, we'll write the ``PublisherBookListView`` view itself::
from django.shortcuts import get_object_or_404
from django.views.generic import ListView
from some_app.models import Book, Publisher
class PublisherBookListView(ListView):
context_object_name = "book_list"
template_name = "books/books_by_publisher.html",
def get_queryset(self):
publisher = get_object_or_404(Publisher, name__iexact=self.args[0])
return Book.objects.filter(publisher=publisher)
As you can see, it's quite easy to add more logic to the queryset selection;
if we wanted, we could use ``self.request.user`` to filter using the current
user, or other more complex logic.
We can also add the publisher into the context at the same time, so we can
use it in the template::
class PublisherBookListView(ListView):
context_object_name = "book_list"
template_name = "books/books_by_publisher.html",
def get_queryset(self):
self.publisher = get_object_or_404(Publisher, name__iexact=self.args[0])
return Book.objects.filter(publisher=self.publisher)
def get_context_data(self, **kwargs):
# Call the base implementation first to get a context
context = ListView.get_context_data(self, **kwargs)
# Add in the publisher
context['publisher'] = self.publisher
return context
Performing extra work
---------------------
The last common pattern we'll look at involves doing some extra work before
or after calling the generic view.
Imagine we had a ``last_accessed`` field on our ``Author`` object that we were
using to keep track of the last time anybody looked at that author::
# models.py
class Author(models.Model):
salutation = models.CharField(max_length=10)
first_name = models.CharField(max_length=30)
last_name = models.CharField(max_length=40)
email = models.EmailField()
headshot = models.ImageField(upload_to='/tmp')
last_accessed = models.DateTimeField()
The generic ``DetailView`` class, of course, wouldn't know anything about this
field, but once again we could easily write a custom view to keep that field
updated.
First, we'd need to add an author detail bit in the URLconf to point to a
custom view:
.. parsed-literal::
from some_app.views import AuthorDetailView
urlpatterns = patterns('',
#...
**(r'^authors/(?P<pk>\\d+)/$', AuthorDetailView.as_view()),**
)
Then we'd write our new view - ``get_object`` is the method that retrieves the
object, so we simply override it and wrap the call::
import datetime
from some_app.models import Author
from django.views.generic import DetailView
from django.shortcuts import get_object_or_404
class AuthorDetailView(DetailView):
queryset = Author.objects.all()
def get_object(self, **kwargs):
# Call the superclass
object = DetailView.get_object(self, **kwargs)
# Record the lass accessed date
object.last_accessed = datetime.datetime.now()
object.save()
# Return the object
return object
.. note::
This code won't actually work unless you create a
``books/author_detail.html`` template.
.. note::
The URLconf here uses the named group ``pk`` - this name is the default
name that DetailView uses to find the value of the primary key used to
filter the queryset.
If you want to change it, you'll need to do your own ``get()`` call
on ``self.queryset`` using the new named parameter from ``self.kwargs``.
More than just HTML
-------------------
So far, we've been focusing on rendering templates to generate
responses. However, that's not all generic views can do.
Each generic view is composed out of a series of mixins, and each
mixin contributes a little piece of the entire view. Some of these
mixins -- such as
:class:`~django.views.generic.base.TemplateResponseMixin` -- are
specifically designed for rendering content to a HTML response using a
template. However, you can write your own mixins that perform
different rendering behavior.
For example, you a simple JSON mixin might look something like this::
class JSONResponseMixin(object):
def render_to_response(self, context):
"Returns a JSON response containing 'context' as payload"
return self.get_json_response(self.convert_context_to_json(context))
def get_json_response(self, content, **httpresponse_kwargs):
"Construct an `HttpResponse` object."
return http.HttpResponse(content,
content_type='application/json',
**httpresponse_kwargs)
def convert_context_to_json(self, context):
"Convert the context dictionary into a JSON object"
# Note: This is *EXTREMELY* naive; in reality, you'll need
# to do much more complex handling to ensure that arbitrary
# objects -- such as Django model instances or querysets
# -- can be serialized as JSON.
return json.dumps(content)
Then, you could build a JSON-returning
:class:`~django.views.generic.detail.DetailView` by mixing your
:class:`JSONResponseMixin` with the
:class:`~django.views.generic.detail.BaseDetailView` -- (the
:class:`~django.views.generic.detail.DetailView` before template
rendering behavior has been mixed in)::
class JSONDetailView(JSONResponseMixin, BaseDetailView):
pass
This view can then be deployed in the same way as any other
:class:`~django.views.generic.detail.DetailView`, with exactly the
same behavior -- except for the format of the response.
If you want to be really adventurous, you could even mix a
:class:`~django.views.generic.detail.DetailView` subclass that is able
to return *both* HTML and JSON content, depending on some property of
the HTTP request, such as a query argument or a HTTP header. Just mix
in both the :class:`JSONResponseMixin` and a
:class:`~django.views.generic.detail.SingleObjectTemplateResponseMixin`,
and override the implementation of :func:`render_to_response()` to defer
to the appropriate subclass depending on the type of response that the user
requested::
class HybridDetailView(JSONResponseMixin, SingleObjectTemplateResponseMixin, BaseDetailView):
def render_to_response(self, context):
# Look for a 'format=json' GET argument
if self.request.GET.get('format','html') == 'json':
return JSONResponseMixin.render_to_response(self, context)
else:
return SingleObjectTemplateResponseMixin.render_to_response(self, context)
Because of the way that Python resolves method overloading, the local
:func:``render_to_response()`` implementation will override the
versions provided by :class:`JSONResponseMixin` and
:class:`~django.views.generic.detail.SingleObjectTemplateResponseMixin`.

127
docs/topics/generic-views-migration.txt Normal file
View File

@@ -0,0 +1,127 @@
======================================
Migrating function-based generic views
======================================
All the :doc:`function-based generic views</ref/generic-views>`
that existed in Django 1.2 have analogs as :doc:`class-based generic
views</ref/class-based-views>` in Django 1.3. The feature set
exposed in those function-based views can be replicated in a
class-based way.
How to migrate
==============
Replace generic views with generic classes
------------------------------------------
Existing usage of function-based generic views should be replaced with
their class-based analogs:
==================================================== ====================================================
Old function-based generic view New class-based generic view
==================================================== ====================================================
``django.views.generic.simple.direct_to_template`` :class:`django.views.generic.base.TemplateView`
``django.views.generic.simple.redirect_to`` :class:`django.views.generic.base.RedirectView`
``django.views.generic.list_detail.object_list`` :class:`django.views.generic.list.ListView`
``django.views.generic.list_detail.object_detail`` :class:`django.views.generic.detail.DetailView`
``django.views.generic.create_update.create_object`` :class:`django.views.generic.edit.CreateView`
``django.views.generic.create_update.update_object`` :class:`django.views.generic.edit.UpdateView`
``django.views.generic.create_update.delete_object`` :class:`django.views.generic.edit.DeleteView`
``django.views.generic.date_based.archive_index`` :class:`django.views.generic.dates.ArchiveIndexView`
``django.views.generic.date_based.archive_year`` :class:`django.views.generic.dates.YearArchiveView`
``django.views.generic.date_based.archive_month`` :class:`django.views.generic.dates.MonthArchiveView`
``django.views.generic.date_based.archive_week`` :class:`django.views.generic.dates.WeekArchiveView`
``django.views.generic.date_based.archive_day`` :class:`django.views.generic.dates.DayArchiveView`
``django.views.generic.date_based.archive_today`` :class:`django.views.generic.dates.TodayArchiveView`
``django.views.generic.date_based.object_detail`` :class:`django.views.generic.dates.DateDetailView`
==================================================== ====================================================
To do this, replace the reference to the generic view function with
a ``as_view()`` instantiation of the class-based view. For example,
the old-style ``direct_to_template`` pattern::
('^about/$', direct_to_template, {'template': 'about.html'})
can be replaced with an instance of
:class:`~django.views.generic.base.TemplateView`::
('^about/$', TemplateView.as_view(template_name='about.html'))
``template`` argument to ``direct_to_template`` views
-----------------------------------------------------
The ``template`` argument to the ``direct_to_template`` view has been renamed
``template_name``. This has ben done to maintain consistency with other views.
``object_id`` argument to detail views
--------------------------------------
The object_id argument to the ``object_detail`` view has been renamed
``pk`` on the :class:`~django.views.generic.detail.DetailView`.
``template_object_name``
------------------------
``template_object_name`` has been renamed ``context_object_name``,
reflecting the fact that the context data can be used for purposes
other than template rendering (e.g., to populate JSON output).
The ``_list`` suffix on list views
----------------------------------
In a function-based :class:`ListView`, the ``template_object_name``
was appended with the suffix ``'_list'`` to yield the final context
variable name. In a class-based ``ListView``, the
``context_object_name`` is used verbatim.
``extra_context``
-----------------
Function-based generic views provided an ``extra_context`` argument
as way to insert extra items into the context at time of rendering.
Class-based views don't provide an ``extra_context`` argument.
Instead, you subclass the view, overriding :meth:`get_context_data()`.
For example::
class MyListView(ListView):
def get_context_data(self, **kwargs):
context = super(MyListView, self).get_context_data(**kwargs)
context.update({
'foo': 42,
'bar': 37
})
return context
``mimetype``
------------
Some function-based generic views provided a ``mimetype`` argument
as way to control the mimetype of the response.
Class-based views don't provide a ``mimetype`` argument. Instead, you
subclass the view, overriding
:meth:`TemplateResponseMixin.get_response()` and pass in arguments for
the HttpResponse constructor. For example::
class MyListView(ListView):
def get_response(self, content, **kwargs):
return super(MyListView, self).get_response(content,
content_type='application/json', **kwargs)
``context_processors``
----------------------
Some function-based generic views provided a ``context_processors``
argument that could be used to force the use of specialized context
processors when rendering template content.
Class-based views don't provide a ``context_processors`` argument.
Instead, you subclass the view, overriding
:meth:`TemplateResponseMixin.get_context_instance()`. For example::
class MyListView(ListView):
def get_context_instance(self, context):
return RequestContext(self.request,
context,
processors=[custom_processor])

10
docs/topics/index.txt
View File

@@ -12,7 +12,8 @@ Introductions to all the key parts of Django you'll need to know:
forms/index
forms/modelforms
templates
generic-views
class-based-views
generic-views-migration
files
testing
auth
@@ -26,3 +27,10 @@ Introductions to all the key parts of Django you'll need to know:
settings
signals
Deprecated features
-------------------
.. toctree::
:maxdepth: 1
generic-views