mirror of https://github.com/django/django.git
226 lines
8.3 KiB
Plaintext
226 lines
8.3 KiB
Plaintext
======================
|
||
Multiple object mixins
|
||
======================
|
||
|
||
``MultipleObjectMixin``
|
||
=======================
|
||
|
||
.. class:: django.views.generic.list.MultipleObjectMixin
|
||
|
||
A mixin that can be used to display a list of objects.
|
||
|
||
If ``paginate_by`` is specified, Django will paginate the results returned
|
||
by this. You can specify the page number in the URL in one of two ways:
|
||
|
||
* Use the ``page`` parameter in the URLconf. For example, this is what
|
||
your URLconf might look like::
|
||
|
||
path("objects/page<int:page>/", PaginatedView.as_view()),
|
||
|
||
* Pass the page number via the ``page`` query-string parameter. For
|
||
example, a URL would look like this:
|
||
|
||
.. code-block:: text
|
||
|
||
/objects/?page=3
|
||
|
||
These values and lists are 1-based, not 0-based, so the first page would be
|
||
represented as page ``1``.
|
||
|
||
For more on pagination, read the :doc:`pagination documentation
|
||
</topics/pagination>`.
|
||
|
||
As a special case, you are also permitted to use ``last`` as a value for
|
||
``page``:
|
||
|
||
.. code-block:: text
|
||
|
||
/objects/?page=last
|
||
|
||
This allows you to access the final page of results without first having to
|
||
determine how many pages there are.
|
||
|
||
Note that ``page`` *must* be either a valid page number or the value
|
||
``last``; any other value for ``page`` will result in a 404 error.
|
||
|
||
**Extends**
|
||
|
||
* :class:`django.views.generic.base.ContextMixin`
|
||
|
||
**Methods and Attributes**
|
||
|
||
.. attribute:: allow_empty
|
||
|
||
A boolean specifying whether to display the page if no objects are
|
||
available. If this is ``False`` and no objects are available, the view
|
||
will raise a 404 instead of displaying an empty page. By default, this
|
||
is ``True``.
|
||
|
||
.. attribute:: model
|
||
|
||
The model that this view will display data for. Specifying ``model
|
||
= Foo`` is effectively the same as specifying ``queryset =
|
||
Foo.objects.all()``, where ``objects`` stands for ``Foo``’s
|
||
:ref:`default manager <default-managers>`.
|
||
|
||
.. attribute:: queryset
|
||
|
||
A ``QuerySet`` that represents the objects. If provided, the value of
|
||
``queryset`` supersedes the value provided for :attr:`model`.
|
||
|
||
.. warning::
|
||
|
||
``queryset`` is a class attribute with a *mutable* value so care
|
||
must be taken when using it directly. Before using it, either call
|
||
its :meth:`~django.db.models.query.QuerySet.all` method or
|
||
retrieve it with :meth:`get_queryset` which takes care of the
|
||
cloning behind the scenes.
|
||
|
||
.. attribute:: ordering
|
||
|
||
A string or list of strings specifying the ordering to apply to the ``queryset``.
|
||
Valid values are the same as those for :meth:`~django.db.models.query.QuerySet.order_by`.
|
||
|
||
.. attribute:: paginate_by
|
||
|
||
An integer specifying how many objects should be displayed per page. If
|
||
this is given, the view will paginate objects with
|
||
``paginate_by`` objects per page. The view will
|
||
expect either a ``page`` query string parameter (via ``request.GET``)
|
||
or a ``page`` variable specified in the URLconf.
|
||
|
||
.. attribute:: paginate_orphans
|
||
|
||
An integer specifying the number of "overflow" objects the last page
|
||
can contain. This extends the :attr:`paginate_by` limit on the last
|
||
page by up to ``paginate_orphans``, in order to keep the last page from
|
||
having a very small number of objects.
|
||
|
||
.. attribute:: page_kwarg
|
||
|
||
A string specifying the name to use for the page parameter.
|
||
The view will expect this parameter to be available either as a query
|
||
string parameter (via ``request.GET``) or as a kwarg variable specified
|
||
in the URLconf. Defaults to ``page``.
|
||
|
||
.. attribute:: paginator_class
|
||
|
||
The paginator class to be used for pagination. By default,
|
||
:class:`django.core.paginator.Paginator` is used. If the custom paginator
|
||
class doesn't have the same constructor interface as
|
||
:class:`django.core.paginator.Paginator`, you will also need to
|
||
provide an implementation for :meth:`get_paginator`.
|
||
|
||
.. attribute:: context_object_name
|
||
|
||
Designates the name of the variable to use in the context.
|
||
|
||
.. method:: get_queryset()
|
||
|
||
Get the list of items for this view. This must be an iterable and may
|
||
be a queryset (in which queryset-specific behavior will be enabled).
|
||
|
||
.. method:: get_ordering()
|
||
|
||
Returns a string (or iterable of strings) that defines the ordering that
|
||
will be applied to the ``queryset``.
|
||
|
||
Returns :attr:`ordering` by default.
|
||
|
||
.. method:: paginate_queryset(queryset, page_size)
|
||
|
||
Returns a 4-tuple containing (``paginator``, ``page``, ``object_list``,
|
||
``is_paginated``).
|
||
|
||
Constructed by paginating ``queryset`` into pages of size ``page_size``.
|
||
If the request contains a ``page`` argument, either as a captured URL
|
||
argument or as a GET argument, ``object_list`` will correspond to the
|
||
objects from that page.
|
||
|
||
.. method:: get_paginate_by(queryset)
|
||
|
||
Returns the number of items to paginate by, or ``None`` for no
|
||
pagination. By default this returns the value of :attr:`paginate_by`.
|
||
|
||
.. method:: get_paginator(queryset, per_page, orphans=0, allow_empty_first_page=True)
|
||
|
||
Returns an instance of the paginator to use for this view. By default,
|
||
instantiates an instance of :attr:`paginator_class`.
|
||
|
||
.. method:: get_paginate_orphans()
|
||
|
||
An integer specifying the number of "overflow" objects the last page
|
||
can contain. By default this returns the value of
|
||
:attr:`paginate_orphans`.
|
||
|
||
.. method:: get_allow_empty()
|
||
|
||
Return a boolean specifying whether to display the page if no objects
|
||
are available. If this method returns ``False`` and no objects are
|
||
available, the view will raise a 404 instead of displaying an empty
|
||
page. By default, this is ``True``.
|
||
|
||
.. method:: get_context_object_name(object_list)
|
||
|
||
Return the context variable name that will be used to contain
|
||
the list of data that this view is manipulating. If
|
||
``object_list`` is a queryset of Django objects and
|
||
:attr:`context_object_name` is not set,
|
||
the context name will be the ``model_name`` of the model that
|
||
the queryset is composed from, with postfix ``'_list'``
|
||
appended. For example, the model ``Article`` would have a
|
||
context object named ``article_list``.
|
||
|
||
.. method:: get_context_data(**kwargs)
|
||
|
||
Returns context data for displaying the list of objects.
|
||
|
||
**Context**
|
||
|
||
* ``object_list``: The list of objects that this view is displaying. If
|
||
``context_object_name`` is specified, that variable will also be set
|
||
in the context, with the same value as ``object_list``.
|
||
|
||
* ``is_paginated``: A boolean representing whether the results are
|
||
paginated. Specifically, this is set to ``False`` if no page size has
|
||
been specified, or if the available objects do not span multiple
|
||
pages.
|
||
|
||
* ``paginator``: An instance of
|
||
:class:`django.core.paginator.Paginator`. If the page is not
|
||
paginated, this context variable will be ``None``.
|
||
|
||
* ``page_obj``: An instance of
|
||
:class:`django.core.paginator.Page`. If the page is not paginated,
|
||
this context variable will be ``None``.
|
||
|
||
|
||
``MultipleObjectTemplateResponseMixin``
|
||
=======================================
|
||
|
||
.. class:: django.views.generic.list.MultipleObjectTemplateResponseMixin
|
||
|
||
A mixin class that performs template-based response rendering for views
|
||
that operate upon a list of object instances. Requires that the view it is
|
||
mixed with provides ``self.object_list``, the list of object instances that
|
||
the view is operating on. ``self.object_list`` may be, but is not required
|
||
to be, a :class:`~django.db.models.query.QuerySet`.
|
||
|
||
**Extends**
|
||
|
||
* :class:`~django.views.generic.base.TemplateResponseMixin`
|
||
|
||
**Methods and Attributes**
|
||
|
||
.. attribute:: template_name_suffix
|
||
|
||
The suffix to append to the auto-generated candidate template name.
|
||
Default suffix is ``_list``.
|
||
|
||
.. method:: get_template_names()
|
||
|
||
Returns a list of candidate template names. Returns the following list:
|
||
|
||
* the value of ``template_name`` on the view (if provided)
|
||
* ``<app_label>/<model_name><template_name_suffix>.html``
|