root/django/branches/gis/docs/generic_views.txt

=============
Generic views
=============

Writing Web applications can be monotonous, because we repeat certain patterns
again and again. In Django, the most common of these patterns have been
abstracted into "generic views" that let you quickly provide common views of
an object without actually needing to write any Python code.

Django's generic views contain the following:

    * A set of views for doing list/detail interfaces (for example,
      Django's `documentation index`_ and `detail pages`_).

    * A set of views for year/month/day archive pages and associated
      detail and "latest" pages (for example, the Django weblog's year_,
      month_, day_, detail_, and latest_ pages).

    * A set of views for creating, editing, and deleting objects.

.. _`documentation index`: http://www.djangoproject.com/documentation/
.. _`detail pages`: http://www.djangoproject.com/documentation/faq/
.. _year: http://www.djangoproject.com/weblog/2005/
.. _month: http://www.djangoproject.com/weblog/2005/jul/
.. _day: http://www.djangoproject.com/weblog/2005/jul/20/
.. _detail: http://www.djangoproject.com/weblog/2005/jul/20/autoreload/
.. _latest: http://www.djangoproject.com/weblog/

All of these views are used by creating configuration dictionaries in
your URLconf files and passing those dictionaries as the third member of the
URLconf tuple for a given pattern. For example, here's the URLconf for the
simple weblog app that drives the blog on djangoproject.com::

    from django.conf.urls.defaults import *
    from django_website.apps.blog.models import Entry

    info_dict = {
        'queryset': Entry.objects.all(),
        'date_field': 'pub_date',
    }

    urlpatterns = patterns('django.views.generic.date_based',
       (r'^(?P<year>\d{4})/(?P<month>[a-z]{3})/(?P<day>\w{1,2})/(?P<slug>[-\w]+)/$', 'object_detail', info_dict),
       (r'^(?P<year>\d{4})/(?P<month>[a-z]{3})/(?P<day>\w{1,2})/$',               'archive_day',   info_dict),
       (r'^(?P<year>\d{4})/(?P<month>[a-z]{3})/$',                                'archive_month', info_dict),
       (r'^(?P<year>\d{4})/$',                                                    'archive_year',  info_dict),
       (r'^$',                                                                    'archive_index', info_dict),
    )

As you can see, this URLconf defines a few options in ``info_dict``.
``'queryset'`` gives the generic view a ``QuerySet`` of objects to use (in this
case, all of the ``Entry`` objects) and tells the generic view which model is
being used.

Documentation of each generic view follows, along with a list of all keyword
arguments that a generic view expects. Remember that as in the example above,
arguments may either come from the URL pattern (as ``month``, ``day``,
``year``, etc. do above) or from the additional-information dictionary (as for
``queryset``, ``date_field``, etc.).

Most generic views require the ``queryset`` key, which is a ``QuerySet``
instance; see the `database API docs`_ for more information about ``Queryset``
objects.

Most views also take an optional ``extra_context`` dictionary that you can use
to pass any auxiliary information you wish to the view. The values in the
``extra_context`` dictionary can be either functions (or other callables) or
other objects. Functions are evaluated just before they are passed to the
template. However, note that QuerySets retrieve and cache their data when they
are first evaluated, so if you want to pass in a QuerySet via
``extra_context`` that is always fresh you need to wrap it in a function or
lambda that returns the QuerySet.

.. _database API docs: ../db-api/

"Simple" generic views
======================

The ``django.views.generic.simple`` module contains simple views to handle a
couple of common cases: rendering a template when no view logic is needed,
and issuing a redirect.

``django.views.generic.simple.direct_to_template``
--------------------------------------------------

Description
~~~~~~~~~~~

Renders a given template, passing it a ``{{ params }}`` template variable,
which is a dictionary of the parameters captured in the URL.

Required arguments
~~~~~~~~~~~~~~~~~~

``template``
    The full name of a template to use.

Optional arguments
~~~~~~~~~~~~~~~~~~

``extra_context``
    A dictionary of values to add to the template context. By default, this is
    an empty dictionary. If a value in the dictionary is callable, the generic
    view will call it just before rendering the template.

``mimetype``
    The MIME type to use for the resulting document. Defaults to the value of
    the ``DEFAULT_CONTENT_TYPE`` setting.

**Example:**

Given the following URL patterns::

    urlpatterns = patterns('django.views.generic.simple',
        (r'^foo/$',             'direct_to_template', {'template': 'foo_index.html'}),
        (r'^foo/(?P<id>\d+)/$', 'direct_to_template', {'template': 'foo_detail.html'}),
    )

... a request to ``/foo/`` would render the template ``foo_index.html``, and a
request to ``/foo/15/`` would render the ``foo_detail.html`` with a context
variable ``{{ params.id }}`` that is set to ``15``.

``django.views.generic.simple.redirect_to``
-------------------------------------------

Description
~~~~~~~~~~~

Redirects to a given URL.

The given URL may contain dictionary-style string formatting, which will be
interpolated against the parameters captured in the URL.

If the given URL is ``None``, Django will return an ``HttpResponseGone`` (410).

Required arguments
~~~~~~~~~~~~~~~~~~

``url``
    The URL to redirect to, as a string. Or ``None`` to raise a 410 (Gone)
    HTTP error.

**Example:**

This example redirects from ``/foo/<id>/`` to ``/bar/<id>/``::

    urlpatterns = patterns('django.views.generic.simple',
        ('^foo/(?P<id>\d+)/$', 'redirect_to', {'url': '/bar/%(id)s/'}),
    )

This example returns a 410 HTTP error for requests to ``/bar/``::

    urlpatterns = patterns('django.views.generic.simple',
        ('^bar/$', 'redirect_to', {'url': None}),
    )

Date-based generic views
========================

Date-based generic views (in the module ``django.views.generic.date_based``)
are views for displaying drilldown pages for date-based data.

``django.views.generic.date_based.archive_index``
-------------------------------------------------

Description
~~~~~~~~~~~

A top-level index page showing the "latest" objects, by date. Objects with
a date in the *future* are not included unless you set ``allow_future`` to
``True``.

Required arguments
~~~~~~~~~~~~~~~~~~

``queryset``
    A ``QuerySet`` of objects for which the archive serves.

``date_field``
    The name of the ``DateField`` or ``DateTimeField`` in the ``QuerySet``'s
    model that the date-based archive should use to determine the objects on
    the page.

Optional arguments
~~~~~~~~~~~~~~~~~~

``num_latest``
    The number of latest objects to send to the template context. By default,
    it's 15.

``template_name``
    The full name of a template to use in rendering the page. This lets you
    override the default template name (see below).

``template_loader``
    The template loader to use when loading the template. By default, it's
    ``django.template.loader``.

``extra_context``
    A dictionary of values to add to the template context. By default, this is
    an empty dictionary. If a value in the dictionary is callable, the generic
    view will call it just before rendering the template.

``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``.

``context_processors``
    A list of template-context processors to apply to the view's template. See
    the `RequestContext docs`_.

``mimetype``
    The MIME type to use for the resulting document. Defaults to the value of
    the ``DEFAULT_CONTENT_TYPE`` setting.

``allow_future``
    A boolean specifying whether to include "future" objects on this page,
    where "future" means objects in which the field specified in ``date_field``
    is greater than the current date/time. By default, this is ``False``.

``template_object_name`` (**New in Django development version**)
    Designates the name of the template variable to use in the template
    context. By default, this is ``'latest'``.

Template name
~~~~~~~~~~~~~

If ``template_name`` isn't specified, this view will use the template
``<app_label>/<model_name>_archive.html`` by default, where:

    * ``<model_name>`` is your model's name in all lowercase. For a model
      ``StaffMember``, that'd be ``staffmember``.

    * ``<app_label>`` is the right-most part of the full Python path to
      your model's app. For example, if your model lives in
      ``apps/blog/models.py``, that'd be ``blog``.

Template context
~~~~~~~~~~~~~~~~

In addition to ``extra_context``, the template's context will be:

``date_list``
    A list of ``datetime.date`` objects representing all years that have
    objects available according to ``queryset``. These are ordered in reverse.
    This is equivalent to ``queryset.dates(date_field, 'year')[::-1]``.

``latest``
    The ``num_latest`` objects in the system, ordered descending by
    ``date_field``. For example, if ``num_latest`` is ``10``, then ``latest``
    will be a list of the latest 10 objects in ``queryset``.

    **New in Django development version:** This variable's name depends on the
    ``template_object_name`` parameter, which is ``'latest'`` by default.
    If ``template_object_name`` is ``'foo'``, this variable's name will be
    ``foo``.

.. _RequestContext docs: ../templates_python/#subclassing-context-requestcontext

``django.views.generic.date_based.archive_year``
------------------------------------------------

Description
~~~~~~~~~~~

A yearly archive page showing all available months in a given year. Objects
with a date in the *future* are not displayed unless you set ``allow_future``
to ``True``.

Required arguments
~~~~~~~~~~~~~~~~~~

``year``
    The four-digit year for which the archive serves.

``queryset``
    A ``QuerySet`` of objects for which the archive serves.

``date_field``
    The name of the ``DateField`` or ``DateTimeField`` in the ``QuerySet``'s
    model that the date-based archive should use to determine the objects on
    the page.

Optional arguments
~~~~~~~~~~~~~~~~~~

``template_name``
    The full name of a template to use in rendering the page. This lets you
    override the default template name (see below).

``template_loader``
    The template loader to use when loading the template. By default, it's
    ``django.template.loader``.

``extra_context``
    A dictionary of values to add to the template context. By default, this is
    an empty dictionary. If a value in the dictionary is callable, the generic
    view will call it just before rendering the template.

``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
    ``False``.

``context_processors``
    A list of template-context processors to apply to the view's template. See
    the `RequestContext docs`_.

``template_object_name``
    Designates the name of the template variable to use in the template
    context. By default, this is ``'object'``. The view will append ``'_list'``
    to the value of this parameter in determining the variable's name.

``make_object_list``
    A boolean specifying whether to retrieve the full  list of objects for this
    year and pass those to the template. If ``True``, this list of objects will
    be made available to the template as ``object_list``. (The name
    ``object_list`` may be different; see the docs for ``object_list`` in the
    "Template context" section below.) By default, this is ``False``.

``mimetype``
    The MIME type to use for the resulting document. Defaults to the value of
    the ``DEFAULT_CONTENT_TYPE`` setting.

``allow_future``
    A boolean specifying whether to include "future" objects on this page,
    where "future" means objects in which the field specified in ``date_field``
    is greater than the current date/time. By default, this is ``False``.

Template name
~~~~~~~~~~~~~

If ``template_name`` isn't specified, this view will use the template
``<app_label>/<model_name>_archive_year.html`` by default.

Template context
~~~~~~~~~~~~~~~~

In addition to ``extra_context``, the template's context will be:

``date_list``
    A list of ``datetime.date`` objects representing all months that have
    objects available in the given year, according to ``queryset``, in
    ascending order.

``year``
    The given year, as a four-character string.

``object_list``
    If the ``make_object_list`` parameter is ``True``, this will be set to a
    list of objects available for the given year, ordered by the date field.
    This variable's name depends on the ``template_object_name`` parameter,
    which is ``'object'`` by default. If ``template_object_name`` is ``'foo'``,
    this variable's name will be ``foo_list``.

    If ``make_object_list`` is ``False``, ``object_list`` will be passed to the
    template as an empty list.

``django.views.generic.date_based.archive_month``
-------------------------------------------------

Description
~~~~~~~~~~~

A monthly archive page showing all objects in a given month. Objects with a
date in the *future* are not displayed unless you set ``allow_future`` to
``True``.

Required arguments
~~~~~~~~~~~~~~~~~~

``year``
    The four-digit year for which the archive serves (a string).

``month``
    The month for which the archive serves, formatted according to the
    ``month_format`` argument.

``queryset``
    A ``QuerySet`` of objects for which the archive serves.

``date_field``
    The name of the ``DateField`` or ``DateTimeField`` in the ``QuerySet``'s
    model that the date-based archive should use to determine the objects on
    the page.

Optional arguments
~~~~~~~~~~~~~~~~~~

``month_format``
    A format string that regulates what format the ``month`` parameter uses.
    This should be in the syntax accepted by Python's ``time.strftime``. (See
    the `strftime docs`_.) It's set to ``"%b"`` by default, which is a three-
    letter month abbreviation. To change it to use numbers, use ``"%m"``.

``template_name``
    The full name of a template to use in rendering the page. This lets you
    override the default template name (see below).

``template_loader``
    The template loader to use when loading the template. By default, it's
    ``django.template.loader``.

``extra_context``
    A dictionary of values to add to the template context. By default, this is
    an empty dictionary. If a value in the dictionary is callable, the generic
    view will call it just before rendering the template.

``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
    ``False``.

``context_processors``
    A list of template-context processors to apply to the view's template. See
    the `RequestContext docs`_.

``template_object_name``
    Designates the name of the template variable to use in the template
    context. By default, this is ``'object'``. The view will append ``'_list'``
    to the value of this parameter in determining the variable's name.

``mimetype``
    The MIME type to use for the resulting document. Defaults to the value of
    the ``DEFAULT_CONTENT_TYPE`` setting.

``allow_future``
    A boolean specifying whether to include "future" objects on this page,
    where "future" means objects in which the field specified in ``date_field``
    is greater than the current date/time. By default, this is ``False``.

Template name
~~~~~~~~~~~~~

If ``template_name`` isn't specified, this view will use the template
``<app_label>/<model_name>_archive_month.html`` by default.

Template context
~~~~~~~~~~~~~~~~

In addition to ``extra_context``, the template's context will be:

``month``
    A ``datetime.date`` object representing the given month.

``next_month``
    A ``datetime.date`` object representing the first day of the next month. If
     the next month is in the future, this will be ``None``.

``previous_month``
    A ``datetime.date`` object representing the first day of the previous
    month. Unlike ``next_month``, this will never be ``None``.

``object_list``
    A list of objects available for the given month. This variable's name
    depends on the ``template_object_name`` parameter, which is ``'object'`` by
    default. If ``template_object_name`` is ``'foo'``, this variable's name
    will be ``foo_list``.

.. _strftime docs: http://www.python.org/doc/current/lib/module-time.html#l2h-1941

``django.views.generic.date_based.archive_week``
------------------------------------------------

Description
~~~~~~~~~~~

A weekly archive page showing all objects in a given week. Objects with a date
in the *future* are not displayed unless you set ``allow_future`` to ``True``.

Required arguments
~~~~~~~~~~~~~~~~~~

``year``
    The four-digit year for which the archive serves (a string).

``week``
    The week of the year for which the archive serves (a string). Weeks start
    with Sunday.

``queryset``
    A ``QuerySet`` of objects for which the archive serves.

``date_field``
    The name of the ``DateField`` or ``DateTimeField`` in the ``QuerySet``'s
    model that the date-based archive should use to determine the objects on
    the page.

Optional arguments
~~~~~~~~~~~~~~~~~~

``template_name``
    The full name of a template to use in rendering the page. This lets you
    override the default template name (see below).

``template_loader``
    The template loader to use when loading the template. By default, it's
    ``django.template.loader``.

``extra_context``
    A dictionary of values to add to the template context. By default, this is
    an empty dictionary. If a value in the dictionary is callable, the generic
    view will call it just before rendering the template.

``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``.

``context_processors``
    A list of template-context processors to apply to the view's template. See
    the `RequestContext docs`_.

``template_object_name``
    Designates the name of the template variable to use in the template
    context. By default, this is ``'object'``. The view will append ``'_list'``
    to the value of this parameter in determining the variable's name.

``mimetype``
    The MIME type to use for the resulting document. Defaults to the value of
    the ``DEFAULT_CONTENT_TYPE`` setting.

``allow_future``
    A boolean specifying whether to include "future" objects on this page,
    where "future" means objects in which the field specified in ``date_field``
    is greater than the current date/time. By default, this is ``False``.

Template name
~~~~~~~~~~~~~

If ``template_name`` isn't specified, this view will use the template
``<app_label>/<model_name>_archive_week.html`` by default.

Template context
~~~~~~~~~~~~~~~~

In addition to ``extra_context``, the template's context will be:

``week``
    A ``datetime.date`` object representing the first day of the given week.

``object_list``
    A list of objects available for the given week. This variable's name
    depends on the ``template_object_name`` parameter, which is ``'object'`` by
    default. If ``template_object_name`` is ``'foo'``, this variable's name
    will be ``foo_list``.

``django.views.generic.date_based.archive_day``
-----------------------------------------------

Description
~~~~~~~~~~~

A day archive page showing all objects in a given day. Days in the future throw
a 404 error, regardless of whether any objects exist for future days, unless
you set ``allow_future`` to ``True``.

Required arguments
~~~~~~~~~~~~~~~~~~

``year``
    The four-digit year for which the archive serves (a string).

``month``
    The month for which the archive serves, formatted according to the
    ``month_format`` argument.

``day``
    The day for which the archive serves, formatted according to the
    ``day_format`` argument.

``queryset``
    A ``QuerySet`` of objects for which the archive serves.

``date_field``
    The name of the ``DateField`` or ``DateTimeField`` in the ``QuerySet``'s
    model that the date-based archive should use to determine the objects on
    the page.

Optional arguments
~~~~~~~~~~~~~~~~~~

``month_format``
    A format string that regulates what format the ``month`` parameter uses.
    This should be in the syntax accepted by Python's ``time.strftime``. (See
    the `strftime docs`_.) It's set to ``"%b"`` by default, which is a three-
    letter month abbreviation. To change it to use numbers, use ``"%m"``.

``day_format``
    Like ``month_format``, but for the ``day`` parameter. It defaults to
    ``"%d"`` (day of the month as a decimal number, 01-31).

``template_name``
    The full name of a template to use in rendering the page. This lets you
    override the default template name (see below).

``template_loader``
    The template loader to use when loading the template. By default, it's
    ``django.template.loader``.

``extra_context``
    A dictionary of values to add to the template context. By default, this is
    an empty dictionary. If a value in the dictionary is callable, the generic
    view will call it just before rendering the template.

``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
    ``False``.

``context_processors``
    A list of template-context processors to apply to the view's template. See
    the `RequestContext docs`_.

``template_object_name``
     Designates the name of the template variable to use in the template
     context. By default, this is ``'object'``. The view will append
     ``'_list'`` to the value of this parameter in determining the variable's
     name.

``mimetype``
    The MIME type to use for the resulting document. Defaults to the value of
    the ``DEFAULT_CONTENT_TYPE`` setting.

``allow_future``
    A boolean specifying whether to include "future" objects on this page,
    where "future" means objects in which the field specified in ``date_field``
    is greater than the current date/time. By default, this is ``False``.

Template name
~~~~~~~~~~~~~

If ``template_name`` isn't specified, this view will use the template
``<app_label>/<model_name>_archive_day.html`` by default.

Template context
~~~~~~~~~~~~~~~~

In addition to ``extra_context``, the template's context will be:

``day``
    A ``datetime.date`` object representing the given day.

``next_day``
    A ``datetime.date`` object representing the next day. If the next day is in
    the future, this will be ``None``.

``previous_day``
    A ``datetime.date`` object representing the given day. Unlike ``next_day``,
    this will never be ``None``.

``object_list``
    A list of objects available for the given day. This variable's name depends
    on the ``template_object_name`` parameter, which is ``'object'`` by
    default. If ``template_object_name`` is ``'foo'``, this variable's name
    will be ``foo_list``.

``django.views.generic.date_based.archive_today``
-------------------------------------------------

Description
~~~~~~~~~~~

A day archive page showing all objects for *today*. This is exactly the same as
``archive_day``, except the ``year``/``month``/``day`` arguments are not used,
and today's date is used instead.

``django.views.generic.date_based.object_detail``
-------------------------------------------------

Description
~~~~~~~~~~~

A page representing an individual object. If the object has a date value in the
future, the view will throw a 404 error by default, unless you set
``allow_future`` to ``True``.

Required arguments
~~~~~~~~~~~~~~~~~~

``year``
    The object's four-digit year (a string).

``month``
    The object's month , formatted according to the ``month_format`` argument.

``day``
    The object's day , formatted according to the ``day_format`` argument.

``queryset``
    A ``QuerySet`` that contains the object.

``date_field``
    The name of the ``DateField`` or ``DateTimeField`` in the ``QuerySet``'s
    model that the generic view should use to look up the object according to
    ``year``, ``month`` and ``day``.

Either ``object_id`` or (``slug`` *and* ``slug_field``) is required.
    If you provide ``object_id``, it should be the value of the primary-key
    field for the object being displayed on this page.

    Otherwise, ``slug`` should be the slug of the given object, and
    ``slug_field`` should be the name of the slug field in the ``QuerySet``'s
    model. By default, ``slug_field`` is ``'slug'``.

Optional arguments
~~~~~~~~~~~~~~~~~~

``month_format``
    A format string that regulates what format the ``month`` parameter uses.
    This should be in the syntax accepted by Python's ``time.strftime``. (See
    the `strftime docs`_.) It's set to ``"%b"`` by default, which is a three-
    letter month abbreviation. To change it to use numbers, use ``"%m"``.

``day_format``
    Like ``month_format``, but for the ``day`` parameter. It defaults to
    ``"%d"`` (day of the month as a decimal number, 01-31).

``template_name``
    The full name of a template to use in rendering the page. This lets you
    override the default template name (see below).

``template_name_field``
    The name of a field on the object whose value is the template name to use.
    This lets you store template names in the data. In other words, if your
    object has a field ``'the_template'`` that contains a string
    ``'foo.html'``, and you set ``template_name_field`` to ``'the_template'``,
    then the generic view for this object will use the template ``'foo.html'``.

    It's a bit of a brain-bender, but it's useful in some cases.

``template_loader``
    The template loader to use when loading the  template. By default, it's
    ``django.template.loader``.

``extra_context``
    A dictionary of values to add to the template context. By default, this is
    an empty dictionary. If a value in the dictionary is callable, the generic
    view will call it just before rendering the template.

``context_processors``
    A list of template-context processors to apply to the view's template. See
    the `RequestContext docs`_.

``template_object_name``
    Designates the name of the template variable to use in the template
    context. By default, this is ``'object'``.

``mimetype``
    The MIME type to use for the resulting document. Defaults to the value of
    the ``DEFAULT_CONTENT_TYPE`` setting.

``allow_future``
    A boolean specifying whether to include "future" objects on this page,
    where "future" means objects in which the field specified in ``date_field``
    is greater than the current date/time. By default, this is ``False``.

Template name
~~~~~~~~~~~~~

If ``template_name`` isn't specified, this view will use the template
``<app_label>/<model_name>_detail.html`` by default.

Template context
~~~~~~~~~~~~~~~~

In addition to ``extra_context``, the template's context will be:

``object``
    The object. This variable's name depends on the ``template_object_name``
    parameter, which is ``'object'`` by default. If ``template_object_name`` is
    ``'foo'``, this variable's name will be ``foo``.

List/detail generic views
=========================

The list-detail generic-view framework (in the
``django.views.generic.list_detail`` module) is similar to the date-based one,
except the former simply has two views: a list of objects and an individual
object page.

``django.views.generic.list_detail.object_list``
------------------------------------------------

Description
~~~~~~~~~~~

A page representing a list of objects.

Required arguments
~~~~~~~~~~~~~~~~~~

``queryset``
    A ``QuerySet`` that represents the objects.

Optional arguments
~~~~~~~~~~~~~~~~~~

``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 ``GET``) or a ``page`` variable specified in the URLconf. See `Notes
    on pagination`_ below.

``page``
    The current (1-based) page number, as an integer, or the string ``'last'``.
    See `Notes on pagination`_ below.

``template_name``
    The full name of a template to use in rendering the page. This lets you
    override the default template name (see below).

``template_loader``
    The template loader to use when loading the template. By default, it's
    ``django.template.loader``.

``extra_context``
    A dictionary of values to add to the template context. By default, this is
    an empty dictionary. If a value in the dictionary is callable, the generic
    view will call it just before rendering the template.

``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``.

``context_processors``
    A list of template-context processors to apply to the view's template. See
    the `RequestContext docs`_.

``template_object_name``
    Designates the name of the template variable to use in the template
    context. By default, this is ``'object'``. The view will append ``'_list'``
    to the value of this parameter in determining the variable's name.

``mimetype``
    The MIME type to use for the resulting document. Defaults to the value of
    the ``DEFAULT_CONTENT_TYPE`` setting.

Template name
~~~~~~~~~~~~~

If ``template_name`` isn't specified, this view will use the template
``<app_label>/<model_name>_list.html`` by default.

Template context
~~~~~~~~~~~~~~~~

In addition to ``extra_context``, the template's context will be:

``object_list``
    The list of objects. This variable's name depends on the
    ``template_object_name`` parameter, which is ``'object'`` by default. If
    ``template_object_name`` is ``'foo'``, this variable's name will be
    ``foo_list``.

``is_paginated``
    A boolean representing whether the results are paginated. Specifically,
    this is set to ``False`` if the number of available objects is less than or
    equal to ``paginate_by``.

If the results are paginated, the context will contain these extra variables:

``paginator`` (**New in Django development version**)
    An instance of ``django.core.paginator.Paginator``.

``page_obj`` (**New in Django development version**)
    An instance of ``django.core.paginator.Page``.

See the `pagination documentation`_ for more information on the ``Paginator``
and ``Page`` objects.

Notes on pagination
~~~~~~~~~~~~~~~~~~~

If ``paginate_by`` is specified, Django will paginate the results. 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::

        (r'^objects/page(?P<page>[0-9]+)/$', 'object_list', dict(info_dict))

    * Pass the page number via the ``page`` query-string parameter. For
      example, a URL would look like this::

        /objects/?page=3

    * To loop over all the available page numbers, use the ``page_range``
      variable. You can iterate over the list provided by ``page_range``
      to create a link to every page of results.

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 `pagination documentation`_.

.. _`pagination documentation`: ../pagination/

**New in Django development version:**

As a special case, you are also permitted to use ``last`` as a value for
``page``::

    /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.

``django.views.generic.list_detail.object_detail``
--------------------------------------------------

A page representing an individual object.

Description
~~~~~~~~~~~

A page representing an individual object.

Required arguments
~~~~~~~~~~~~~~~~~~

``queryset``
    A ``QuerySet`` that contains the object.

Either ``object_id`` or (``slug`` *and* ``slug_field``)
    If you provide ``object_id``, it should be the value of the primary-key
    field for the object being displayed on this page.

    Otherwise, ``slug`` should be the slug of the given object, and
    ``slug_field`` should be the name of the slug field in the ``QuerySet``'s
    model. By default, ``slug_field`` is ``'slug'``.

Optional arguments
~~~~~~~~~~~~~~~~~~

``template_name``
    The full name of a template to use in rendering the page. This lets you
    override the default template name (see below).

``template_name_field``
    The name of a field on the object whose value is the template name to use.
    This lets you store template names in the data. In other words, if your
    object has a field ``'the_template'`` that contains a string
    ``'foo.html'``, and you set ``template_name_field`` to ``'the_template'``,
    then the generic view for this object will use the template ``'foo.html'``.

    It's a bit of a brain-bender, but it's useful in some cases.

``template_loader``
    The template loader to use when loading the template. By default, it's
    ``django.template.loader``.

``extra_context``
    A dictionary of values to add to the template context. By default, this is
    an empty dictionary. If a value in the dictionary is callable, the generic
    view will call it just before rendering the template.

``context_processors``
    A list of template-context processors to apply to the view's template. See
    the `RequestContext docs`_.

``template_object_name``
    Designates the name of the template variable to use in the template
    context. By default, this is ``'object'``.

``mimetype``
    The MIME type to use for the resulting document. Defaults to the value of
    the ``DEFAULT_CONTENT_TYPE`` setting.

Template name
~~~~~~~~~~~~~

If ``template_name`` isn't specified, this view will use the template
``<app_label>/<model_name>_detail.html`` by default.

Template context
~~~~~~~~~~~~~~~~

In addition to ``extra_context``, the template's context will be:

``object``
    The object. This variable's name depends on the ``template_object_name``
    parameter, which is ``'object'`` by default. If ``template_object_name`` is
    ``'foo'``, this variable's name will be ``foo``.

Create/update/delete generic views
==================================

The ``django.views.generic.create_update`` module contains a set of functions
for creating, editing and deleting objects.

**Changed in Django development version:**

``django.views.generic.create_update.create_object`` and
``django.views.generic.create_update.update_object`` now use the new `forms
library`_ to build and display the form.

.. _forms library: ../forms/

``django.views.generic.create_update.create_object``
----------------------------------------------------

Description
~~~~~~~~~~~

A page that displays a form for creating an object, redisplaying the form with
validation errors (if there are any) and saving the object.

Required arguments
~~~~~~~~~~~~~~~~~~

Either ``form_class`` or ``model``
    If you provide ``form_class``, it should be a ``django.forms.ModelForm``
    subclass.  Use this argument when you need to customize the model's form.
    See the `ModelForm docs`_ for more information.

    Otherwise, ``model`` should be a Django model class and the form used will
    be a standard ``ModelForm`` for ``model``.

Optional arguments
~~~~~~~~~~~~~~~~~~

``post_save_redirect``
    A URL to which the view will redirect after saving the object. By default,
    it's ``object.get_absolute_url()``.

    ``post_save_redirect`` may contain dictionary string formatting, which will
    be interpolated against the object's field attributes. For example, you
    could use ``post_save_redirect="/polls/%(slug)s/"``.

``login_required``
    A boolean that designates whether a user must be logged in, in order to see
    the page and save changes. This hooks into the Django `authentication
    system`_. By default, this is ``False``.

    If this is ``True``, and a non-logged-in user attempts to visit this page
    or save the form, Django will redirect the request to ``/accounts/login/``.

``template_name``
    The full name of a template to use in rendering the page. This lets you
    override the default template name (see below).

``template_loader``
    The template loader to use when loading the template. By default, it's
    ``django.template.loader``.

``extra_context``
    A dictionary of values to add to the template context. By default, this is
    an empty dictionary. If a value in the dictionary is callable, the generic
    view will call it just before rendering the template.

``context_processors``
    A list of template-context processors to apply to the view's template. See
    the `RequestContext docs`_.

Template name
~~~~~~~~~~~~~

If ``template_name`` isn't specified, this view will use the template
``<app_label>/<model_name>_form.html`` by default.

Template context
~~~~~~~~~~~~~~~~

In addition to ``extra_context``, the template's context will be:

``form``
    A ``django.forms.ModelForm`` instance representing the form for creating
    the object. This lets you refer to form fields easily in the template
    system.

    For example, if the model has two fields, ``name`` and ``address``::

        <form action="" method="post">
        <p>{{ form.name.label_tag }} {{ form.name }}</p>
        <p>{{ form.address.label_tag }} {{ form.address }}</p>
        </form>

    See the `forms documentation`_ for more information about using ``Form``
    objects in templates.

.. _authentication system: ../authentication/
.. _ModelForm docs: ../modelforms/
.. _forms documentation: ../forms/

``django.views.generic.create_update.update_object``
----------------------------------------------------

Description
~~~~~~~~~~~

A page that displays a form for editing an existing object, redisplaying the
form with validation errors (if there are any) and saving changes to the
object. This uses a form automatically generated from the object's
model class.

Required arguments
~~~~~~~~~~~~~~~~~~

Either ``form_class`` or ``model``
    If you provide ``form_class``, it should be a ``django.forms.ModelForm``
    subclass.  Use this argument when you need to customize the model's form.
    See the `ModelForm docs`_ for more information.

    Otherwise, ``model`` should be a Django model class and the form used will
    be a standard ``ModelForm`` for ``model``.

Either ``object_id`` or (``slug`` *and* ``slug_field``)
    If you provide ``object_id``, it should be the value of the primary-key
    field for the object being displayed on this page.

    Otherwise, ``slug`` should be the slug of the given object, and
    ``slug_field`` should be the name of the slug field in the ``QuerySet``'s
    model. By default, ``slug_field`` is ``'slug'``.

Optional arguments
~~~~~~~~~~~~~~~~~~

``post_save_redirect``
    A URL to which the view will redirect after saving the object. By default,
    it's ``object.get_absolute_url()``.

    ``post_save_redirect`` may contain dictionary string formatting, which will
    be interpolated against the object's field attributes. For example, you
    could use ``post_save_redirect="/polls/%(slug)s/"``.

``login_required``
    A boolean that designates whether a user must be logged in, in order to see
    the page and save changes. This hooks into the Django `authentication
    system`_. By default, this is ``False``.

    If this is ``True``, and a non-logged-in user attempts to visit this page
    or save the form, Django will redirect the request to ``/accounts/login/``.

``template_name``
    The full name of a template to use in rendering the page. This lets you
    override the default template name (see below).

``template_loader``
    The template loader to use when loading the template. By default, it's
    ``django.template.loader``.

``extra_context``
    A dictionary of values to add to the template context. By default, this is
    an empty dictionary. If a value in the dictionary is callable, the generic
    view will call it just before rendering the template.

``context_processors``: A list of template-context processors to apply to
      the view's template. See the `RequestContext docs`_.

``template_object_name``
    Designates the name of the template variable to use in the template
    context. By default, this is ``'object'``.

Template name
~~~~~~~~~~~~~

If ``template_name`` isn't specified, this view will use the template
``<app_label>/<model_name>_form.html`` by default.

Template context
~~~~~~~~~~~~~~~~

In addition to ``extra_context``, the template's context will be:

``form``
    A ``django.forms.ModelForm`` instance representing the form for editing the
    object. This lets you refer to form fields easily in the template system.

    For example, if the model has two fields, ``name`` and ``address``::