Refs #7864 -- Updates to documentation for the oldforms/newforms switch.
* Moved forms.txt to oldforms.txt * Moved newforms.txt to forms.txt * Updated links and most references to "newforms" (there are a few sections that need a more significant rewrite). git-svn-id: http://code.djangoproject.com/svn/django/trunk@8020 bcc190cf-cafb-0310-a4f2-bffc1f526a37
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@ -76,7 +76,7 @@ Requires the sites_ contrib package to be installed as well.
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formtools
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=========
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A set of high-level abstractions for Django forms (django.newforms).
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A set of high-level abstractions for Django forms (django.forms).
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django.contrib.formtools.preview
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--------------------------------
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@ -115,6 +115,6 @@ change:
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.. _template language: ../templates/
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.. _transactions: ../transactions/
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.. _url dispatch: ../url_dispatch/
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.. _forms and validation: ../forms/
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.. _forms and validation: ../oldforms/
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.. _serialization: ../serialization/
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.. _authentication: ../authentication/
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@ -517,7 +517,7 @@ It's your responsibility to provide the login form in a template called
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template context variables:
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* ``form``: A ``Form`` object representing the login form. See the
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`newforms documentation`_ for more on ``Form`` objects.
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`forms documentation`_ for more on ``FormWrapper`` objects.
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* ``next``: The URL to redirect to after successful login. This may contain
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a query string, too.
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* ``site_name``: The name of the current ``Site``, according to the
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@ -557,7 +557,7 @@ block::
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{% endblock %}
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.. _newforms documentation: ../newforms/
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.. _forms documentation: ../forms/
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.. _site framework docs: ../sites/
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Other built-in views
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@ -111,7 +111,7 @@ into the precise details of what ``Field`` can do later on; for now, suffice it
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to say that everything descends from ``Field`` and then customizes key pieces
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of the class behavior.
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.. _form fields: ../newforms/#fields
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.. _form fields: ../forms/#fields
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It's important to realize that a Django field class is not what is stored in
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your model attributes. The model attributes contain normal Python objects. The
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@ -493,8 +493,8 @@ This assumes we're imported a ``MyFormField`` field class (which has its own
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default widget). This document doesn't cover the details of writing custom form
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fields.
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.. _helper functions: ../newforms/#generating-forms-for-models
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.. _forms documentation: ../newforms/
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.. _helper functions: ../forms/#generating-forms-for-models
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.. _forms documentation: ../forms/
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``get_internal_type(self)``
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~~~~~~~~~~~~~~~~~~~~~~~~~~~
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@ -20,13 +20,13 @@ For this reason, Django provides a few helper functions that let you create a
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``form_for_model()``
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--------------------
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The method ``django.newforms.form_for_model()`` creates a form based on the
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The method ``django.forms.form_for_model()`` creates a form based on the
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definition of a specific model. Pass it the model class, and it will return a
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``Form`` class that contains a form field for each model field.
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For example::
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>>> from django.newforms import form_for_model
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>>> from django.forms import form_for_model
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# Create the form class.
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>>> ArticleForm = form_for_model(Article)
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@ -93,11 +93,11 @@ the full list of conversions:
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As you might expect, the ``ForeignKey`` and ``ManyToManyField`` model field
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types are special cases:
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* ``ForeignKey`` is represented by ``django.newforms.ModelChoiceField``,
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* ``ForeignKey`` is represented by ``django.forms.ModelChoiceField``,
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which is a ``ChoiceField`` whose choices are a model ``QuerySet``.
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* ``ManyToManyField`` is represented by
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``django.newforms.ModelMultipleChoiceField``, which is a
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``django.forms.ModelMultipleChoiceField``, which is a
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``MultipleChoiceField`` whose choices are a model ``QuerySet``.
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In addition, each generated form field has attributes set as follows:
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@ -228,7 +228,7 @@ Using an alternate base class
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~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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If you want to add custom methods to the form generated by
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``form_for_model()``, write a class that extends ``django.newforms.BaseForm``
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``form_for_model()``, write a class that extends ``django.forms.BaseForm``
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and contains your custom methods. Then, use the ``form`` argument to
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``form_for_model()`` to tell it to use your custom form as its base class.
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For example::
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@ -412,8 +412,8 @@ note is that the form display in the ``GET`` branch of the function
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will use the values from the ``message`` instance as initial values for the
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form field.
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.. _contact form: ../newforms/#simple-view-example
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.. _`simple example view`: ../newforms/#simple-view-example
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.. _contact form: ../forms/#simple-view-example
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.. _`simple example view`: ../forms/#simple-view-example
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When should you use ``form_for_model()`` and ``form_for_instance()``?
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~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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@ -13,7 +13,7 @@ Python class.
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Overview
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=========
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Given a ``django.newforms.Form`` subclass that you define, this application
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Given a ``django.forms.Form`` subclass that you define, this application
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takes care of the following workflow:
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1. Displays the form as HTML on a Web page.
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@ -65,7 +65,7 @@ How to use ``FormPreview``
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from myapp.preview import SomeModelFormPreview
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from myapp.models import SomeModel
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from django import newforms as forms
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from django import forms
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...and add the following line to the appropriate model in your URLconf::
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@ -17,7 +17,7 @@ etc.
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The term "wizard," in this context, is `explained on Wikipedia`_.
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.. _explained on Wikipedia: http://en.wikipedia.org/wiki/Wizard_%28software%29
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.. _forms: ../newforms/
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.. _forms: ../forms/
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How it works
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============
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@ -41,7 +41,7 @@ Usage
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This application handles as much machinery for you as possible. Generally, you
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just have to do these things:
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1. Define a number of ``django.newforms`` ``Form`` classes -- one per wizard
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1. Define a number of ``django.forms`` ``Form`` classes -- one per wizard
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page.
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2. Create a ``FormWizard`` class that specifies what to do once all of your
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forms have been submitted and validated. This also lets you override some
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@ -55,8 +55,8 @@ Defining ``Form`` classes
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=========================
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The first step in creating a form wizard is to create the ``Form`` classes.
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These should be standard ``django.newforms`` ``Form`` classes, covered in the
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`newforms documentation`_.
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These should be standard ``django.forms`` ``Form`` classes, covered in the
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`forms documentation`_.
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These classes can live anywhere in your codebase, but convention is to put them
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in a file called ``forms.py`` in your application.
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collects the sender's e-mail address and subject, and the second page collects
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the message itself. Here's what the ``forms.py`` might look like::
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from django import newforms as forms
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from django import forms
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class ContactForm1(forms.Form):
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subject = forms.CharField(max_length=100)
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@ -78,7 +78,7 @@ the message itself. Here's what the ``forms.py`` might look like::
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data between pages, you may not include a ``FileField`` in any form except the
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last one.
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.. _newforms documentation: ../newforms/
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.. _forms documentation: ../forms/
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Creating a ``FormWizard`` class
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===============================
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and validated. This method is passed two arguments:
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* ``request`` -- an HttpRequest_ object
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* ``form_list`` -- a list of ``django.newforms`` ``Form`` classes
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* ``form_list`` -- a list of ``django.forms`` ``Form`` classes
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In this simplistic example, rather than perform any database operation, the
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method simply renders a template of the validated data::
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@ -209,7 +209,7 @@ Default implementation::
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def prefix_for_step(self, step):
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return str(step)
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.. _form prefix documentation: ../newforms/#prefixes-for-forms
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.. _form prefix documentation: ../forms/#prefixes-for-forms
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``render_hash_failure``
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~~~~~~~~~~~~~~~~~~~~~~~
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2983
docs/forms.txt
2983
docs/forms.txt
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<p>{{ form.address.label_tag }} {{ form.address }}</p>
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</form>
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See the `newforms documentation`_ for more information about using
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See the `forms documentation`_ for more information about using
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``Form`` objects in templates.
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.. _authentication system: ../authentication/
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.. _ModelForm docs: ../newforms/modelforms
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.. _newforms documentation: ../newforms/
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.. _forms documentation: ../forms/
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``django.views.generic.create_update.update_object``
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----------------------------------------------------
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@ -33,7 +33,7 @@ Reference
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transactions
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templates
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templates_python
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newforms
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forms
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modelforms
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testing
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sessions
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@ -11,7 +11,7 @@ Inside that package, country- or culture-specific code is organized into
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subpackages, named using `ISO 3166 country codes`_.
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Most of the ``localflavor`` add-ons are localized form components deriving from
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the newforms_ framework -- for example, a ``USStateField`` that knows how to
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the forms_ framework -- for example, a ``USStateField`` that knows how to
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validate U.S. state abbreviations, and a ``FISocialSecurityNumber`` that knows
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how to validate Finnish social security numbers.
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@ -19,7 +19,7 @@ To use one of these localized components, just import the relevant subpackage.
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For example, here's how you can create a form with a field representing a
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French telephone number::
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from django import newforms as forms
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from django import forms
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from django.contrib.localflavor import fr
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class MyForm(forms.Form):
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@ -58,10 +58,10 @@ Countries currently supported by ``localflavor`` are:
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The ``localflavor`` package also includes a ``generic`` subpackage, containing
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useful code that is not specific to one particular country or culture.
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Currently, it defines date and datetime input fields based on those from
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newforms_, but with non-US default formats. Here's an example of how to use
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forms_, but with non-US default formats. Here's an example of how to use
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them::
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from django import newforms as forms
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from django import forms
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from django.contrib.localflavor import generic
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class MyForm(forms.Form):
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@ -92,7 +92,7 @@ them::
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.. _Switzerland: `Switzerland (django.contrib.localflavor.ch)`_
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.. _United Kingdom: `United Kingdom (django.contrib.localflavor.uk)`_
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.. _United States of America: `United States of America (django.contrib.localflavor.us)`_
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.. _newforms: ../newforms/
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.. _forms: ../forms/
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Adding flavors
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==============
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@ -716,7 +716,7 @@ that takes the parameters ``field_data, all_data`` and raises
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Django comes with quite a few validators. They're in ``django.core.validators``.
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.. _validator docs: ../forms/#validators
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.. _validator docs: ../oldforms/#validators
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Verbose field names
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-------------------
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@ -1,6 +1,6 @@
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==========================
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Using newforms with models
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==========================
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=======================
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Using forms with models
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=======================
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``ModelForm``
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=============
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@ -16,7 +16,7 @@ class from a Django model.
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For example::
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>>> from django.newforms import ModelForm
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>>> from django.forms import ModelForm
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# Create the form class.
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>>> class ArticleForm(ModelForm):
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As you might expect, the ``ForeignKey`` and ``ManyToManyField`` model field
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types are special cases:
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* ``ForeignKey`` is represented by ``django.newforms.ModelChoiceField``,
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* ``ForeignKey`` is represented by ``django.forms.ModelChoiceField``,
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which is a ``ChoiceField`` whose choices are a model ``QuerySet``.
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* ``ManyToManyField`` is represented by
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``django.newforms.ModelMultipleChoiceField``, which is a
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``django.forms.ModelMultipleChoiceField``, which is a
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``MultipleChoiceField`` whose choices are a model ``QuerySet``.
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In addition, each generated form field has attributes set as follows:
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@ -121,7 +121,7 @@ A full example
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Consider this set of models::
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from django.db import models
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from django.newforms import ModelForm
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from django.forms import ModelForm
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TITLE_CHOICES = (
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('MR', 'Mr.'),
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@ -240,14 +240,14 @@ For example::
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>>> new_author = f.save()
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Other than the ``save()`` and ``save_m2m()`` methods, a ``ModelForm``
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works exactly the same way as any other ``newforms`` form. For
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works exactly the same way as any other ``forms`` form. For
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example, the ``is_valid()`` method is used to check for validity, the
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``is_multipart()`` method is used to determine whether a form requires
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multipart file upload (and hence whether ``request.FILES`` must be
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passed to the form), etc. See `the standard newforms documentation`_
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passed to the form), etc. See `the standard forms documentation`_
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for more information.
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.. _the standard newforms documentation: ../newforms/
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.. _the standard forms documentation: ../forms/
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Using a subset of fields on the form
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------------------------------------
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2522
docs/newforms.txt
2522
docs/newforms.txt
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===============================
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Forms, fields, and manipulators
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===============================
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Forwards-compatibility note
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===========================
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The legacy forms/manipulators system described in this document is going to be
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replaced in the next Django release. If you're starting from scratch, we
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strongly encourage you not to waste your time learning this. Instead, learn and
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use the django.forms system, which we have begun to document in the
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`forms documentation`_.
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If you have legacy form/manipulator code, read the "Migration plan" section in
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that document to understand how we're making the switch.
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.. _forms documentation: ../forms/
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Introduction
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============
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Once you've got a chance to play with Django's admin interface, you'll probably
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wonder if the fantastic form validation framework it uses is available to user
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code. It is, and this document explains how the framework works.
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We'll take a top-down approach to examining Django's form validation framework,
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because much of the time you won't need to use the lower-level APIs. Throughout
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this document, we'll be working with the following model, a "place" object::
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from django.db import models
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PLACE_TYPES = (
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(1, 'Bar'),
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(2, 'Restaurant'),
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(3, 'Movie Theater'),
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(4, 'Secret Hideout'),
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)
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class Place(models.Model):
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name = models.CharField(max_length=100)
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address = models.CharField(max_length=100, blank=True)
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city = models.CharField(max_length=50, blank=True)
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state = models.USStateField()
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zip_code = models.CharField(max_length=5, blank=True)
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place_type = models.IntegerField(choices=PLACE_TYPES)
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class Admin:
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pass
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def __unicode__(self):
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return self.name
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Defining the above class is enough to create an admin interface to a ``Place``,
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but what if you want to allow public users to submit places?
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Automatic Manipulators
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======================
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|
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The highest-level interface for object creation and modification is the
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**automatic Manipulator** framework. An automatic manipulator is a utility
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class tied to a given model that "knows" how to create or modify instances of
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that model and how to validate data for the object. Automatic Manipulators come
|
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in two flavors: ``AddManipulators`` and ``ChangeManipulators``. Functionally
|
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they are quite similar, but the former knows how to create new instances of the
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model, while the latter modifies existing instances. Both types of classes are
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automatically created when you define a new class::
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>>> from mysite.myapp.models import Place
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>>> Place.AddManipulator
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<class 'django.models.manipulators.AddManipulator'>
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>>> Place.ChangeManipulator
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<class 'django.models.manipulators.ChangeManipulator'>
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Using the ``AddManipulator``
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----------------------------
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We'll start with the ``AddManipulator``. Here's a very simple view that takes
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POSTed data from the browser and creates a new ``Place`` object::
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from django.shortcuts import render_to_response
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from django.http import Http404, HttpResponse, HttpResponseRedirect
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from django import oldforms as forms
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from mysite.myapp.models import Place
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def naive_create_place(request):
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"""A naive approach to creating places; don't actually use this!"""
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# Create the AddManipulator.
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manipulator = Place.AddManipulator()
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# Make a copy of the POSTed data so that do_html2python can
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# modify it in place (request.POST is immutable).
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new_data = request.POST.copy()
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# Convert the request data (which will all be strings) into the
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# appropriate Python types for those fields.
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manipulator.do_html2python(new_data)
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# Save the new object.
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new_place = manipulator.save(new_data)
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# It worked!
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return HttpResponse("Place created: %s" % new_place)
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|
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The ``naive_create_place`` example works, but as you probably can tell, this
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view has a number of problems:
|
||||
|
||||
* No validation of any sort is performed. If, for example, the ``name`` field
|
||||
isn't given in ``request.POST``, the save step will cause a database error
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because that field is required. Ugly.
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|
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* Even if you *do* perform validation, there's still no way to give that
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information to the user in any sort of useful way.
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* You'll have to separately create a form (and view) that submits to this
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page, which is a pain and is redundant.
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|
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Let's dodge these problems momentarily to take a look at how you could create a
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view with a form that submits to this flawed creation view::
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|
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def naive_create_place_form(request):
|
||||
"""Simplistic place form view; don't actually use anything like this!"""
|
||||
# Create a FormWrapper object that the template can use. Ignore
|
||||
# the last two arguments to FormWrapper for now.
|
||||
form = forms.FormWrapper(Place.AddManipulator(), {}, {})
|
||||
return render_to_response('places/naive_create_form.html', {'form': form})
|
||||
|
||||
(This view, as well as all the following ones, has the same imports as in the
|
||||
first example above.)
|
||||
|
||||
The ``forms.FormWrapper`` object is a wrapper that templates can
|
||||
easily deal with to create forms. Here's the ``naive_create_form.html``
|
||||
template::
|
||||
|
||||
{% extends "base.html" %}
|
||||
|
||||
{% block content %}
|
||||
<h1>Create a place:</h1>
|
||||
|
||||
<form method="post" action="../do_new/">
|
||||
<p><label for="id_name">Name:</label> {{ form.name }}</p>
|
||||
<p><label for="id_address">Address:</label> {{ form.address }}</p>
|
||||
<p><label for="id_city">City:</label> {{ form.city }}</p>
|
||||
<p><label for="id_state">State:</label> {{ form.state }}</p>
|
||||
<p><label for="id_zip_code">Zip:</label> {{ form.zip_code }}</p>
|
||||
<p><label for="id_place_type">Place type:</label> {{ form.place_type }}</p>
|
||||
<input type="submit" />
|
||||
</form>
|
||||
{% endblock %}
|
||||
|
||||
Before we get back to the problems with these naive set of views, let's go over
|
||||
some salient points of the above template:
|
||||
|
||||
* Field "widgets" are handled for you: ``{{ form.field }}`` automatically
|
||||
creates the "right" type of widget for the form, as you can see with the
|
||||
``place_type`` field above.
|
||||
|
||||
* There isn't a way just to spit out the form. You'll still need to define
|
||||
how the form gets laid out. This is a feature: Every form should be
|
||||
designed differently. Django doesn't force you into any type of mold.
|
||||
If you must use tables, use tables. If you're a semantic purist, you can
|
||||
probably find better HTML than in the above template.
|
||||
|
||||
* To avoid name conflicts, the ``id`` values of form elements take the
|
||||
form "id_*fieldname*".
|
||||
|
||||
By creating a creation form we've solved problem number 3 above, but we still
|
||||
don't have any validation. Let's revise the validation issue by writing a new
|
||||
creation view that takes validation into account::
|
||||
|
||||
def create_place_with_validation(request):
|
||||
manipulator = Place.AddManipulator()
|
||||
new_data = request.POST.copy()
|
||||
|
||||
# Check for validation errors
|
||||
errors = manipulator.get_validation_errors(new_data)
|
||||
manipulator.do_html2python(new_data)
|
||||
if errors:
|
||||
return render_to_response('places/errors.html', {'errors': errors})
|
||||
else:
|
||||
new_place = manipulator.save(new_data)
|
||||
return HttpResponse("Place created: %s" % new_place)
|
||||
|
||||
In this new version, errors will be found -- ``manipulator.get_validation_errors``
|
||||
handles all the validation for you -- and those errors can be nicely presented
|
||||
on an error page (templated, of course)::
|
||||
|
||||
{% extends "base.html" %}
|
||||
|
||||
{% block content %}
|
||||
|
||||
<h1>Please go back and correct the following error{{ errors|pluralize }}:</h1>
|
||||
<ul>
|
||||
{% for e in errors.items %}
|
||||
<li>Field "{{ e.0 }}": {{ e.1|join:", " }}</li>
|
||||
{% endfor %}
|
||||
</ul>
|
||||
|
||||
{% endblock %}
|
||||
|
||||
Still, this has its own problems:
|
||||
|
||||
* There's still the issue of creating a separate (redundant) view for the
|
||||
submission form.
|
||||
|
||||
* Errors, though nicely presented, are on a separate page, so the user will
|
||||
have to use the "back" button to fix errors. That's ridiculous and unusable.
|
||||
|
||||
The best way to deal with these issues is to collapse the two views -- the form
|
||||
and the submission -- into a single view. This view will be responsible for
|
||||
creating the form, validating POSTed data, and creating the new object (if the
|
||||
data is valid). An added bonus of this approach is that errors and the form will
|
||||
both be available on the same page, so errors with fields can be presented in
|
||||
context.
|
||||
|
||||
.. admonition:: Philosophy:
|
||||
|
||||
Finally, for the HTTP purists in the audience (and the authorship), this
|
||||
nicely matches the "true" meanings of HTTP GET and HTTP POST: GET fetches
|
||||
the form, and POST creates the new object.
|
||||
|
||||
Below is the finished view::
|
||||
|
||||
def create_place(request):
|
||||
manipulator = Place.AddManipulator()
|
||||
|
||||
if request.method == 'POST':
|
||||
# If data was POSTed, we're trying to create a new Place.
|
||||
new_data = request.POST.copy()
|
||||
|
||||
# Check for errors.
|
||||
errors = manipulator.get_validation_errors(new_data)
|
||||
manipulator.do_html2python(new_data)
|
||||
|
||||
if not errors:
|
||||
# No errors. This means we can save the data!
|
||||
new_place = manipulator.save(new_data)
|
||||
|
||||
# Redirect to the object's "edit" page. Always use a redirect
|
||||
# after POST data, so that reloads don't accidently create
|
||||
# duplicate entires, and so users don't see the confusing
|
||||
# "Repost POST data?" alert box in their browsers.
|
||||
return HttpResponseRedirect("/places/edit/%i/" % new_place.id)
|
||||
else:
|
||||
# No POST, so we want a brand new form without any data or errors.
|
||||
errors = new_data = {}
|
||||
|
||||
# Create the FormWrapper, template, context, response.
|
||||
form = forms.FormWrapper(manipulator, new_data, errors)
|
||||
return render_to_response('places/create_form.html', {'form': form})
|
||||
|
||||
and here's the ``create_form`` template::
|
||||
|
||||
{% extends "base.html" %}
|
||||
|
||||
{% block content %}
|
||||
<h1>Create a place:</h1>
|
||||
|
||||
{% if form.has_errors %}
|
||||
<h2>Please correct the following error{{ form.error_dict|pluralize }}:</h2>
|
||||
{% endif %}
|
||||
|
||||
<form method="post" action=".">
|
||||
<p>
|
||||
<label for="id_name">Name:</label> {{ form.name }}
|
||||
{% if form.name.errors %}*** {{ form.name.errors|join:", " }}{% endif %}
|
||||
</p>
|
||||
<p>
|
||||
<label for="id_address">Address:</label> {{ form.address }}
|
||||
{% if form.address.errors %}*** {{ form.address.errors|join:", " }}{% endif %}
|
||||
</p>
|
||||
<p>
|
||||
<label for="id_city">City:</label> {{ form.city }}
|
||||
{% if form.city.errors %}*** {{ form.city.errors|join:", " }}{% endif %}
|
||||
</p>
|
||||
<p>
|
||||
<label for="id_state">State:</label> {{ form.state }}
|
||||
{% if form.state.errors %}*** {{ form.state.errors|join:", " }}{% endif %}
|
||||
</p>
|
||||
<p>
|
||||
<label for="id_zip_code">Zip:</label> {{ form.zip_code }}
|
||||
{% if form.zip_code.errors %}*** {{ form.zip_code.errors|join:", " }}{% endif %}
|
||||
</p>
|
||||
<p>
|
||||
<label for="id_place_type">Place type:</label> {{ form.place_type }}
|
||||
{% if form.place_type.errors %}*** {{ form.place_type.errors|join:", " }}{% endif %}
|
||||
</p>
|
||||
<input type="submit" />
|
||||
</form>
|
||||
{% endblock %}
|
||||
|
||||
The second two arguments to ``FormWrapper`` (``new_data`` and ``errors``)
|
||||
deserve some mention.
|
||||
|
||||
The first is any "default" data to be used as values for the fields. Pulling
|
||||
the data from ``request.POST``, as is done above, makes sure that if there are
|
||||
errors, the values the user put in aren't lost. If you try the above example,
|
||||
you'll see this in action.
|
||||
|
||||
The second argument is the error list retrieved from
|
||||
``manipulator.get_validation_errors``. When passed into the ``FormWrapper``,
|
||||
this gives each field an ``errors`` item (which is a list of error messages
|
||||
associated with the field) as well as a ``html_error_list`` item, which is a
|
||||
``<ul>`` of error messages. The above template uses these error items to
|
||||
display a simple error message next to each field. The error list is saved as
|
||||
an ``error_dict`` attribute of the ``FormWrapper`` object.
|
||||
|
||||
Using the ``ChangeManipulator``
|
||||
-------------------------------
|
||||
|
||||
The above has covered using the ``AddManipulator`` to create a new object. What
|
||||
about editing an existing one? It's shockingly similar to creating a new one::
|
||||
|
||||
def edit_place(request, place_id):
|
||||
# Get the place in question from the database and create a
|
||||
# ChangeManipulator at the same time.
|
||||
try:
|
||||
manipulator = Place.ChangeManipulator(place_id)
|
||||
except Place.DoesNotExist:
|
||||
raise Http404
|
||||
|
||||
# Grab the Place object in question for future use.
|
||||
place = manipulator.original_object
|
||||
|
||||
if request.method == 'POST':
|
||||
new_data = request.POST.copy()
|
||||
errors = manipulator.get_validation_errors(new_data)
|
||||
manipulator.do_html2python(new_data)
|
||||
if not errors:
|
||||
manipulator.save(new_data)
|
||||
|
||||
# Do a post-after-redirect so that reload works, etc.
|
||||
return HttpResponseRedirect("/places/edit/%i/" % place.id)
|
||||
else:
|
||||
errors = {}
|
||||
# This makes sure the form accurate represents the fields of the place.
|
||||
new_data = manipulator.flatten_data()
|
||||
|
||||
form = forms.FormWrapper(manipulator, new_data, errors)
|
||||
return render_to_response('places/edit_form.html', {'form': form, 'place': place})
|
||||
|
||||
The only real differences are:
|
||||
|
||||
* We create a ``ChangeManipulator`` instead of an ``AddManipulator``.
|
||||
The argument to a ``ChangeManipulator`` is the ID of the object
|
||||
to be changed. As you can see, the initializer will raise an
|
||||
``ObjectDoesNotExist`` exception if the ID is invalid.
|
||||
|
||||
* ``ChangeManipulator.original_object`` stores the instance of the
|
||||
object being edited.
|
||||
|
||||
* We set ``new_data`` based upon ``flatten_data()`` from the manipulator.
|
||||
``flatten_data()`` takes the data from the original object under
|
||||
manipulation, and converts it into a data dictionary that can be used
|
||||
to populate form elements with the existing values for the object.
|
||||
|
||||
* The above example uses a different template, so create and edit can be
|
||||
"skinned" differently if needed, but the form chunk itself is completely
|
||||
identical to the one in the create form above.
|
||||
|
||||
The astute programmer will notice the add and create functions are nearly
|
||||
identical and could in fact be collapsed into a single view. This is left as an
|
||||
exercise for said programmer.
|
||||
|
||||
(However, the even-more-astute programmer will take heed of the note at the top
|
||||
of this document and check out the `generic views`_ documentation if all she
|
||||
wishes to do is this type of simple create/update.)
|
||||
|
||||
Custom forms and manipulators
|
||||
=============================
|
||||
|
||||
All the above is fine and dandy if you just want to use the automatically
|
||||
created manipulators. But the coolness doesn't end there: You can easily create
|
||||
your own custom manipulators for handling custom forms.
|
||||
|
||||
Custom manipulators are pretty simple. Here's a manipulator that you might use
|
||||
for a "contact" form on a website::
|
||||
|
||||
from django import oldforms as forms
|
||||
|
||||
urgency_choices = (
|
||||
(1, "Extremely urgent"),
|
||||
(2, "Urgent"),
|
||||
(3, "Normal"),
|
||||
(4, "Unimportant"),
|
||||
)
|
||||
|
||||
class ContactManipulator(forms.Manipulator):
|
||||
def __init__(self):
|
||||
self.fields = (
|
||||
forms.EmailField(field_name="from", is_required=True),
|
||||
forms.TextField(field_name="subject", length=30, max_length=200, is_required=True),
|
||||
forms.SelectField(field_name="urgency", choices=urgency_choices),
|
||||
forms.LargeTextField(field_name="contents", is_required=True),
|
||||
)
|
||||
|
||||
A certain similarity to Django's models should be apparent. The only required
|
||||
method of a custom manipulator is ``__init__`` which must define the fields
|
||||
present in the manipulator. See the ``django.forms`` module for
|
||||
all the form fields provided by Django.
|
||||
|
||||
You use this custom manipulator exactly as you would use an auto-generated one.
|
||||
Here's a simple function that might drive the above form::
|
||||
|
||||
def contact_form(request):
|
||||
manipulator = ContactManipulator()
|
||||
if request.method == 'POST':
|
||||
new_data = request.POST.copy()
|
||||
errors = manipulator.get_validation_errors(new_data)
|
||||
manipulator.do_html2python(new_data)
|
||||
if not errors:
|
||||
|
||||
# Send e-mail using new_data here...
|
||||
|
||||
return HttpResponseRedirect("/contact/thankyou/")
|
||||
else:
|
||||
errors = new_data = {}
|
||||
form = forms.FormWrapper(manipulator, new_data, errors)
|
||||
return render_to_response('contact_form.html', {'form': form})
|
||||
|
||||
Implementing ``flatten_data`` for custom manipulators
|
||||
------------------------------------------------------
|
||||
|
||||
It is possible (although rarely needed) to replace the default automatically
|
||||
created manipulators on a model with your own custom manipulators. If you do
|
||||
this and you are intending to use those models in generic views, you should
|
||||
also define a ``flatten_data`` method in any ``ChangeManipulator`` replacement.
|
||||
This should act like the default ``flatten_data`` and return a dictionary
|
||||
mapping field names to their values, like so::
|
||||
|
||||
def flatten_data(self):
|
||||
obj = self.original_object
|
||||
return dict(
|
||||
from = obj.from,
|
||||
subject = obj.subject,
|
||||
...
|
||||
)
|
||||
|
||||
In this way, your new change manipulator will act exactly like the default
|
||||
version.
|
||||
|
||||
``FileField`` and ``ImageField`` special cases
|
||||
==============================================
|
||||
|
||||
Dealing with ``FileField`` and ``ImageField`` objects is a little more
|
||||
complicated.
|
||||
|
||||
First, you'll need to make sure that your ``<form>`` element correctly defines
|
||||
the ``enctype`` as ``"multipart/form-data"``, in order to upload files::
|
||||
|
||||
<form enctype="multipart/form-data" method="post" action="/foo/">
|
||||
|
||||
Next, you'll need to treat the field in the template slightly differently. A
|
||||
``FileField`` or ``ImageField`` is represented by *two* HTML form elements.
|
||||
|
||||
For example, given this field in a model::
|
||||
|
||||
photo = model.ImageField('/path/to/upload/location')
|
||||
|
||||
You'd need to display two formfields in the template::
|
||||
|
||||
<p><label for="id_photo">Photo:</label> {{ form.photo }}{{ form.photo_file }}</p>
|
||||
|
||||
The first bit (``{{ form.photo }}``) displays the currently-selected file,
|
||||
while the second (``{{ form.photo_file }}``) actually contains the file upload
|
||||
form field. Thus, at the validation layer you need to check the ``photo_file``
|
||||
key.
|
||||
|
||||
Finally, in your view, make sure to access ``request.FILES``, rather than
|
||||
``request.POST``, for the uploaded files. This is necessary because
|
||||
``request.POST`` does not contain file-upload data.
|
||||
|
||||
For example, following the ``new_data`` convention, you might do something like
|
||||
this::
|
||||
|
||||
new_data = request.POST.copy()
|
||||
new_data.update(request.FILES)
|
||||
|
||||
Validators
|
||||
==========
|
||||
|
||||
One useful feature of manipulators is the automatic validation. Validation is
|
||||
done using a simple validation API: A validator is a callable that raises a
|
||||
``ValidationError`` if there's something wrong with the data.
|
||||
``django.core.validators`` defines a host of validator functions (see below),
|
||||
but defining your own couldn't be easier::
|
||||
|
||||
from django.core import validators
|
||||
from django import oldforms as forms
|
||||
|
||||
class ContactManipulator(forms.Manipulator):
|
||||
def __init__(self):
|
||||
self.fields = (
|
||||
# ... snip fields as above ...
|
||||
forms.EmailField(field_name="to", validator_list=[self.isValidToAddress])
|
||||
)
|
||||
|
||||
def isValidToAddress(self, field_data, all_data):
|
||||
if not field_data.endswith("@example.com"):
|
||||
raise validators.ValidationError("You can only send messages to example.com e-mail addresses.")
|
||||
|
||||
Above, we've added a "to" field to the contact form, but required that the "to"
|
||||
address end with "@example.com" by adding the ``isValidToAddress`` validator to
|
||||
the field's ``validator_list``.
|
||||
|
||||
The arguments to a validator function take a little explanation. ``field_data``
|
||||
is the value of the field in question, and ``all_data`` is a dictionary of all
|
||||
the data being validated.
|
||||
|
||||
.. admonition:: Note::
|
||||
|
||||
At the point validators are called all data will still be
|
||||
strings (as ``do_html2python`` hasn't been called yet).
|
||||
|
||||
Also, because consistency in user interfaces is important, we strongly urge you
|
||||
to put punctuation at the end of your validation messages.
|
||||
|
||||
When are validators called?
|
||||
---------------------------
|
||||
|
||||
After a form has been submitted, Django validates each field in turn. First,
|
||||
if the field is required, Django checks that it is present and non-empty. Then,
|
||||
if that test passes *and the form submission contained data* for that field, all
|
||||
the validators for that field are called in turn. The emphasized portion in the
|
||||
last sentence is important: if a form field is not submitted (because it
|
||||
contains no data -- which is normal HTML behavior), the validators are not
|
||||
run against the field.
|
||||
|
||||
This feature is particularly important for models using
|
||||
``models.BooleanField`` or custom manipulators using things like
|
||||
``forms.CheckBoxField``. If the checkbox is not selected, it will not
|
||||
contribute to the form submission.
|
||||
|
||||
If you would like your validator to run *always*, regardless of whether its
|
||||
attached field contains any data, set the ``always_test`` attribute on the
|
||||
validator function. For example::
|
||||
|
||||
def my_custom_validator(field_data, all_data):
|
||||
# ...
|
||||
my_custom_validator.always_test = True
|
||||
|
||||
This validator will always be executed for any field it is attached to.
|
||||
|
||||
Ready-made validators
|
||||
---------------------
|
||||
|
||||
Writing your own validator is not difficult, but there are some situations
|
||||
that come up over and over again. Django comes with a number of validators
|
||||
that can be used directly in your code. All of these functions and classes
|
||||
reside in ``django/core/validators.py``.
|
||||
|
||||
The following validators should all be self-explanatory. Each one provides a
|
||||
check for the given property:
|
||||
|
||||
* isAlphaNumeric
|
||||
* isAlphaNumericURL
|
||||
* isSlug
|
||||
* isLowerCase
|
||||
* isUpperCase
|
||||
* isCommaSeparatedIntegerList
|
||||
* isCommaSeparatedEmailList
|
||||
* isValidIPAddress4
|
||||
* isNotEmpty
|
||||
* isOnlyDigits
|
||||
* isNotOnlyDigits
|
||||
* isInteger
|
||||
* isOnlyLetters
|
||||
* isValidANSIDate
|
||||
* isValidANSITime
|
||||
* isValidEmail
|
||||
* isValidFloat
|
||||
* isValidImage
|
||||
* isValidImageURL
|
||||
* isValidPhone
|
||||
* isValidQuicktimeVideoURL
|
||||
* isValidURL
|
||||
* isValidHTML
|
||||
* isWellFormedXml
|
||||
* isWellFormedXmlFragment
|
||||
* isExistingURL
|
||||
* isValidUSState
|
||||
* hasNoProfanities
|
||||
|
||||
There are also a group of validators that are slightly more flexible. For
|
||||
these validators, you create a validator instance, passing in the parameters
|
||||
described below. The returned object is a callable that can be used as a
|
||||
validator.
|
||||
|
||||
For example::
|
||||
|
||||
from django.core import validators
|
||||
from django import oldforms as forms
|
||||
|
||||
power_validator = validators.IsAPowerOf(2)
|
||||
|
||||
class InstallationManipulator(forms.Manipulator)
|
||||
def __init__(self):
|
||||
self.fields = (
|
||||
...
|
||||
forms.IntegerField(field_name = "size", validator_list=[power_validator])
|
||||
)
|
||||
|
||||
Here, ``validators.IsAPowerOf(...)`` returned something that could be used as
|
||||
a validator (in this case, a check that a number was a power of 2).
|
||||
|
||||
Each of the standard validators that take parameters have an optional final
|
||||
argument (``error_message``) that is the message returned when validation
|
||||
fails. If no message is passed in, a default message is used.
|
||||
|
||||
``AlwaysMatchesOtherField``
|
||||
Takes a field name and the current field is valid if and only if its value
|
||||
matches the contents of the other field.
|
||||
|
||||
``ValidateIfOtherFieldEquals``
|
||||
Takes three parameters: ``other_field``, ``other_value`` and
|
||||
``validator_list``, in that order. If ``other_field`` has a value of
|
||||
``other_value``, then the validators in ``validator_list`` are all run
|
||||
against the current field.
|
||||
|
||||
``RequiredIfOtherFieldGiven``
|
||||
Takes a field name of the current field is only required if the other
|
||||
field has a value.
|
||||
|
||||
``RequiredIfOtherFieldsGiven``
|
||||
Similar to ``RequiredIfOtherFieldGiven``, except that it takes a list of
|
||||
field names and if any one of the supplied fields has a value provided,
|
||||
the current field being validated is required.
|
||||
|
||||
``RequiredIfOtherFieldNotGiven``
|
||||
Takes the name of the other field and this field is only required if the
|
||||
other field has no value.
|
||||
|
||||
``RequiredIfOtherFieldEquals`` and ``RequiredIfOtherFieldDoesNotEqual``
|
||||
Each of these validator classes takes a field name and a value (in that
|
||||
order). If the given field does (or does not have, in the latter case) the
|
||||
given value, then the current field being validated is required.
|
||||
|
||||
An optional ``other_label`` argument can be passed which, if given, is used
|
||||
in error messages instead of the value. This allows more user friendly error
|
||||
messages if the value itself is not descriptive enough.
|
||||
|
||||
Note that because validators are called before any ``do_html2python()``
|
||||
functions, the value being compared against is a string. So
|
||||
``RequiredIfOtherFieldEquals('choice', '1')`` is correct, whilst
|
||||
``RequiredIfOtherFieldEquals('choice', 1)`` will never result in the
|
||||
equality test succeeding.
|
||||
|
||||
``IsLessThanOtherField``
|
||||
Takes a field name and validates that the current field being validated
|
||||
has a value that is less than (or equal to) the other field's value.
|
||||
Again, comparisons are done using strings, so be cautious about using
|
||||
this function to compare data that should be treated as another type. The
|
||||
string "123" is less than the string "2", for example. If you don't want
|
||||
string comparison here, you will need to write your own validator.
|
||||
|
||||
``NumberIsInRange``
|
||||
Takes two boundary numbers, ``lower`` and ``upper``, and checks that the
|
||||
field is greater than ``lower`` (if given) and less than ``upper`` (if
|
||||
given).
|
||||
|
||||
Both checks are inclusive. That is, ``NumberIsInRange(10, 20)`` will allow
|
||||
values of both 10 and 20. This validator only checks numeric values
|
||||
(e.g., float and integer values).
|
||||
|
||||
``IsAPowerOf``
|
||||
Takes an integer argument and when called as a validator, checks that the
|
||||
field being validated is a power of the integer.
|
||||
|
||||
``IsValidDecimal``
|
||||
Takes a maximum number of digits and number of decimal places (in that
|
||||
order) and validates whether the field is a decimal with no more than the
|
||||
maximum number of digits and decimal places.
|
||||
|
||||
``MatchesRegularExpression``
|
||||
Takes a regular expression (a string) as a parameter and validates the
|
||||
field value against it.
|
||||
|
||||
``AnyValidator``
|
||||
Takes a list of validators as a parameter. At validation time, if the
|
||||
field successfully validates against any one of the validators, it passes
|
||||
validation. The validators are tested in the order specified in the
|
||||
original list.
|
||||
|
||||
``URLMimeTypeCheck``
|
||||
Used to validate URL fields. Takes a list of MIME types (such as
|
||||
``text/plain``) at creation time. At validation time, it verifies that the
|
||||
field is indeed a URL and then tries to retrieve the content at the URL.
|
||||
Validation succeeds if the content could be retrieved and it has a content
|
||||
type from the list used to create the validator.
|
||||
|
||||
``RelaxNGCompact``
|
||||
Used to validate an XML document against a Relax NG compact schema. Takes
|
||||
a file path to the location of the schema and an optional root element
|
||||
(which is wrapped around the XML fragment before validation, if supplied).
|
||||
At validation time, the XML fragment is validated against the schema using
|
||||
the executable specified in the ``JING_PATH`` setting (see the settings_
|
||||
document for more details).
|
||||
|
||||
.. _`generic views`: ../generic_views/
|
||||
.. _`models API`: ../model-api/
|
||||
.. _settings: ../settings/
|
|
@ -17,7 +17,7 @@ Basic file uploads
|
|||
|
||||
Consider a simple form containing a ``FileField``::
|
||||
|
||||
from django import newforms as forms
|
||||
from django import forms
|
||||
|
||||
class UploadFileForm(forms.Form):
|
||||
title = forms.CharField(max_length=50)
|
||||
|
@ -48,7 +48,7 @@ something like::
|
|||
form = UploadFileForm()
|
||||
return render_to_response('upload.html', {'form': form})
|
||||
|
||||
.. _binding uploaded files to a form: ../newforms/#binding-uploaded-files-to-a- form
|
||||
.. _binding uploaded files to a form: ../forms/#binding-uploaded-files-to-a- form
|
||||
|
||||
Notice that we have to pass ``request.FILES`` into the form's constructor; this
|
||||
is how file data gets bound into a form.
|
||||
|
|
Loading…
Reference in New Issue