==============
Editing mixins
==============
The following mixins are used to construct Django's editing views:
* :class:`django.views.generic.edit.FormMixin`
* :class:`django.views.generic.edit.ModelFormMixin`
* :class:`django.views.generic.edit.ProcessFormView`
* :class:`django.views.generic.edit.DeletionMixin`
.. note::
Examples of how these are combined into editing views can be found at
the documentation on ``Generic editing views``.
FormMixin
---------
.. class:: django.views.generic.edit.FormMixin
A mixin class that provides facilities for creating and displaying forms.
**Methods and Attributes**
.. attribute:: initial
A dictionary containing initial data for the form.
.. attribute:: form_class
The form class to instantiate.
.. attribute:: success_url
The URL to redirect to when the form is successfully processed.
.. method:: get_initial()
Retrieve initial data for the form. By default, returns a copy of
:attr:`~django.views.generic.edit.FormMixin.initial`.
.. versionchanged:: 1.4
In Django 1.3, this method was returning the
:attr:`~django.views.generic.edit.FormMixin.initial` class variable
itself.
.. method:: get_form_class()
Retrieve the form class to instantiate. By default
:attr:`.form_class`.
.. method:: get_form(form_class)
Instantiate an instance of ``form_class`` using
:meth:`~django.views.generic.edit.FormMixin.get_form_kwargs`.
.. method:: get_form_kwargs()
Build the keyword arguments required to instantiate the form.
The ``initial`` argument is set to :meth:`.get_initial`. If the
request is a ``POST`` or ``PUT``, the request data (``request.POST``
and ``request.FILES``) will also be provided.
.. method:: get_success_url()
Determine the URL to redirect to when the form is successfully
validated. Returns
:attr:`~django.views.generic.edit.FormMixin.success_url` by default.
.. method:: form_valid(form)
Redirects to
:meth:`~django.views.generic.edit.FormMixin.get_success_url`.
.. method:: form_invalid(form)
Renders a response, providing the invalid form as context.
.. method:: get_context_data(**kwargs)
Populates a context containing the contents of ``kwargs``.
**Context**
* ``form``: The form instance that was generated for the view.
.. note::
Views mixing ``FormMixin`` must provide an implementation of
:meth:`form_valid` and :meth:`form_invalid`.
ModelFormMixin
--------------
.. class:: django.views.generic.edit.ModelFormMixin
A form mixin that works on ``ModelForms``, rather than a standalone form.
Since this is a subclass of
:class:`~django.views.generic.detail.SingleObjectMixin`, instances of this
mixin have access to the
:attr:`~django.views.generic.detail.SingleObjectMixin.model` and
:attr:`~django.views.generic.detail.SingleObjectMixin.queryset` attributes,
describing the type of object that the ``ModelForm`` is manipulating. The
view also provides ``self.object``, the instance being manipulated. If the
instance is being created, ``self.object`` will be ``None``.
**Mixins**
* :class:`django.views.generic.edit.FormMixin`
* :class:`django.views.generic.detail.SingleObjectMixin`
**Methods and Attributes**
.. attribute:: model
A model class. Can be explicitly provided, otherwise will be determined
by examining ``self.object`` or
:attr:`~django.views.generic.detail.SingleObjectMixin.queryset`.
.. attribute:: success_url
The URL to redirect to when the form is successfully processed.
``success_url`` may contain dictionary string formatting, which
will be interpolated against the object's field attributes. For
example, you could use ``success_url="/polls/%(slug)s/"`` to
redirect to a URL composed out of the ``slug`` field on a model.
.. method:: get_form_class()
Retrieve the form class to instantiate. If
:attr:`~django.views.generic.edit.FormMixin.form_class` is provided,
that class will be used. Otherwise, a ``ModelForm`` will be
instantiated using the model associated with the
:attr:`~django.views.generic.detail.SingleObjectMixin.queryset`, or
with the :attr:`~django.views.generic.detail.SingleObjectMixin.model`,
depending on which attribute is provided.
.. method:: get_form_kwargs()
Add the current instance (``self.object``) to the standard
:meth:`~django.views.generic.edit.FormMixin.get_form_kwargs`.
.. method:: get_success_url()
Determine the URL to redirect to when the form is successfully
validated. Returns
:attr:`django.views.generic.edit.ModelFormMixin.success_url` if it is
provided; otherwise, attempts to use the ``get_absolute_url()`` of the
object.
.. method:: form_valid(form)
Saves the form instance, sets the current object for the view, and
redirects to
:meth:`~django.views.generic.edit.FormMixin.get_success_url`.
.. method:: form_invalid()
Renders a response, providing the invalid form as context.
ProcessFormView
---------------
.. class:: django.views.generic.edit.ProcessFormView
A mixin that provides basic HTTP GET and POST workflow.
.. note::
This is named 'ProcessFormView' and inherits directly from
:class:`django.views.generic.base.View`, but breaks if used
independently, so it is more of a mixin.
**Extends**
* :class:`django.views.generic.base.View`
**Methods and Attributes**
.. method:: get(request, *args, **kwargs)
Constructs a form, then renders a response using a context that
contains that form.
.. method:: post(request, *args, **kwargs)
Constructs a form, checks the form for validity, and handles it
accordingly.
.. method:: put(*args, **kwargs)
The ``PUT`` action is also handled and just passes all parameters
through to :meth:`post`.
.. class:: django.views.generic.edit.DeletionMixin
Enables handling of the ``DELETE`` http action.
**Methods and Attributes**
.. attribute:: success_url
The url to redirect to when the nominated object has been
successfully deleted.
.. method:: get_success_url()
Returns the url to redirect to when the nominated object has been
successfully deleted. Returns
:attr:`~django.views.generic.edit.DeletionMixin.success_url` by
default.
