django/docs/topics/generic-views-migration.txt

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======================================
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.
The context data for ``object_list`` views
------------------------------------------
The context provided by :class:`~django.views.generic.list.MultipleObjectMixin`
is quite different from that provided by ``object_list``, with most pagination
related variables replaced by a single ``page_obj`` object. The following are no
longer provided:
* ``first_on_page``
* ``has_next``
* ``has_previous``
* ``hits``
* ``last_on_page``
* ``next``
* ``page_range``
* ``page``
* ``pages``
* ``previous``
* ``results_per_page``
``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
``post_save_redirect`` argument to create and update views
----------------------------------------------------------
The ``post_save_redirect`` argument to the create and update views
has been renamed ``success_url`` on the
:class:`~django.views.generic.edit.ModelFormMixin`.
``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])