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31 KiB
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==================
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Working with forms
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==================
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.. currentmodule:: django.forms
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.. admonition:: About this document
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This document provides an introduction to the basics of web forms and how
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they are handled in Django. For a more detailed look at specific areas of
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the forms API, see :doc:`/ref/forms/api`, :doc:`/ref/forms/fields`, and
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:doc:`/ref/forms/validation`.
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Unless you're planning to build websites and applications that do nothing but
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publish content, and don't accept input from your visitors, you're going to
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need to understand and use forms.
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Django provides a range of tools and libraries to help you build forms to
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accept input from site visitors, and then process and respond to the input.
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HTML forms
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==========
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In HTML, a form is a collection of elements inside ``<form>...</form>`` that
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allow a visitor to do things like enter text, select options, manipulate
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objects or controls, and so on, and then send that information back to the
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server.
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Some of these form interface elements - text input or checkboxes - are built
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into HTML itself. Others are much more complex; an interface that pops up a
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date picker or allows you to move a slider or manipulate controls will
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typically use JavaScript and CSS as well as HTML form ``<input>`` elements to
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achieve these effects.
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As well as its ``<input>`` elements, a form must specify two things:
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* *where*: the URL to which the data corresponding to the user's input should
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be returned
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* *how*: the HTTP method the data should be returned by
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As an example, the login form for the Django admin contains several
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``<input>`` elements: one of ``type="text"`` for the username, one of
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``type="password"`` for the password, and one of ``type="submit"`` for the
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"Log in" button. It also contains some hidden text fields that the user
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doesn't see, which Django uses to determine what to do next.
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It also tells the browser that the form data should be sent to the URL
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specified in the ``<form>``’s ``action`` attribute - ``/admin/`` - and that it
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should be sent using the HTTP mechanism specified by the ``method`` attribute -
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``post``.
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When the ``<input type="submit" value="Log in">`` element is triggered, the
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data is returned to ``/admin/``.
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``GET`` and ``POST``
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--------------------
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``GET`` and ``POST`` are the only HTTP methods to use when dealing with forms.
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Django's login form is returned using the ``POST`` method, in which the browser
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bundles up the form data, encodes it for transmission, sends it to the server,
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and then receives back its response.
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``GET``, by contrast, bundles the submitted data into a string, and uses this
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to compose a URL. The URL contains the address where the data must be sent, as
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well as the data keys and values. You can see this in action if you do a search
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in the Django documentation, which will produce a URL of the form
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``https://docs.djangoproject.com/search/?q=forms&release=1``.
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``GET`` and ``POST`` are typically used for different purposes.
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Any request that could be used to change the state of the system - for example,
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a request that makes changes in the database - should use ``POST``. ``GET``
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should be used only for requests that do not affect the state of the system.
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``GET`` would also be unsuitable for a password form, because the password
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would appear in the URL, and thus, also in browser history and server logs,
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all in plain text. Neither would it be suitable for large quantities of data,
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or for binary data, such as an image. A web application that uses ``GET``
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requests for admin forms is a security risk: it can be easy for an attacker to
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mimic a form's request to gain access to sensitive parts of the system.
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``POST``, coupled with other protections like Django's :doc:`CSRF protection
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</ref/csrf/>` offers more control over access.
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On the other hand, ``GET`` is suitable for things like a web search form,
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because the URLs that represent a ``GET`` request can easily be bookmarked,
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shared, or resubmitted.
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Django's role in forms
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======================
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Handling forms is a complex business. Consider Django's admin, where numerous
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items of data of several different types may need to be prepared for display in
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a form, rendered as HTML, edited using a convenient interface, returned to the
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server, validated and cleaned up, and then saved or passed on for further
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processing.
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Django's form functionality can simplify and automate vast portions of this
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work, and can also do it more securely than most programmers would be able to
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do in code they wrote themselves.
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Django handles three distinct parts of the work involved in forms:
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* preparing and restructuring data to make it ready for rendering
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* creating HTML forms for the data
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* receiving and processing submitted forms and data from the client
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It is *possible* to write code that does all of this manually, but Django can
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take care of it all for you.
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Forms in Django
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===============
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We've described HTML forms briefly, but an HTML ``<form>`` is just one part of
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the machinery required.
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In the context of a web application, 'form' might refer to that HTML
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``<form>``, or to the Django :class:`Form` that produces it, or to the
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structured data returned when it is submitted, or to the end-to-end working
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collection of these parts.
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The Django :class:`Form` class
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------------------------------
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At the heart of this system of components is Django's :class:`Form` class. In
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much the same way that a Django model describes the logical structure of an
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object, its behavior, and the way its parts are represented to us, a
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:class:`Form` class describes a form and determines how it works and appears.
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In a similar way that a model class's fields map to database fields, a form
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class's fields map to HTML form ``<input>`` elements. (A :class:`ModelForm`
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maps a model class's fields to HTML form ``<input>`` elements via a
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:class:`Form`; this is what the Django admin is based upon.)
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A form's fields are themselves classes; they manage form data and perform
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validation when a form is submitted. A :class:`DateField` and a
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:class:`FileField` handle very different kinds of data and have to do
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different things with it.
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A form field is represented to a user in the browser as an HTML "widget" - a
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piece of user interface machinery. Each field type has an appropriate default
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:doc:`Widget class </ref/forms/widgets/>`, but these can be overridden as
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required.
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Instantiating, processing, and rendering forms
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----------------------------------------------
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When rendering an object in Django, we generally:
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#. get hold of it in the view (fetch it from the database, for example)
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#. pass it to the template context
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#. expand it to HTML markup using template variables
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Rendering a form in a template involves nearly the same work as rendering any
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other kind of object, but there are some key differences.
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In the case of a model instance that contained no data, it would rarely if ever
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be useful to do anything with it in a template. On the other hand, it makes
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perfect sense to render an unpopulated form - that's what we do when we want
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the user to populate it.
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So when we handle a model instance in a view, we typically retrieve it from the
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database. When we're dealing with a form we typically instantiate it in the
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view.
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When we instantiate a form, we can opt to leave it empty or prepopulate it, for
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example with:
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* data from a saved model instance (as in the case of admin forms for editing)
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* data that we have collated from other sources
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* data received from a previous HTML form submission
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The last of these cases is the most interesting, because it's what makes it
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possible for users not just to read a website, but to send information back
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to it too.
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Building a form
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===============
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The work that needs to be done
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------------------------------
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Suppose you want to create a simple form on your website, in order to obtain
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the user's name. You'd need something like this in your template:
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.. code-block:: html+django
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<form action="/your-name/" method="post">
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<label for="your_name">Your name: </label>
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<input id="your_name" type="text" name="your_name" value="{{ current_name }}">
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<input type="submit" value="OK">
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</form>
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This tells the browser to return the form data to the URL ``/your-name/``, using
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the ``POST`` method. It will display a text field, labeled "Your name:", and a
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button marked "OK". If the template context contains a ``current_name``
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variable, that will be used to pre-fill the ``your_name`` field.
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You'll need a view that renders the template containing the HTML form, and
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that can supply the ``current_name`` field as appropriate.
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When the form is submitted, the ``POST`` request which is sent to the server
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will contain the form data.
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Now you'll also need a view corresponding to that ``/your-name/`` URL which will
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find the appropriate key/value pairs in the request, and then process them.
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This is a very simple form. In practice, a form might contain dozens or
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hundreds of fields, many of which might need to be prepopulated, and we might
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expect the user to work through the edit-submit cycle several times before
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concluding the operation.
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We might require some validation to occur in the browser, even before the form
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is submitted; we might want to use much more complex fields, that allow the
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user to do things like pick dates from a calendar and so on.
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At this point it's much easier to get Django to do most of this work for us.
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Building a form in Django
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-------------------------
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The :class:`Form` class
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~~~~~~~~~~~~~~~~~~~~~~~
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We already know what we want our HTML form to look like. Our starting point for
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it in Django is this:
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.. code-block:: python
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:caption: ``forms.py``
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from django import forms
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class NameForm(forms.Form):
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your_name = forms.CharField(label='Your name', max_length=100)
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This defines a :class:`Form` class with a single field (``your_name``). We've
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applied a human-friendly label to the field, which will appear in the
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``<label>`` when it's rendered (although in this case, the :attr:`~Field.label`
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we specified is actually the same one that would be generated automatically if
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we had omitted it).
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The field's maximum allowable length is defined by
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:attr:`~CharField.max_length`. This does two things. It puts a
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``maxlength="100"`` on the HTML ``<input>`` (so the browser should prevent the
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user from entering more than that number of characters in the first place). It
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also means that when Django receives the form back from the browser, it will
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validate the length of the data.
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A :class:`Form` instance has an :meth:`~Form.is_valid()` method, which runs
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validation routines for all its fields. When this method is called, if all
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fields contain valid data, it will:
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* return ``True``
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* place the form's data in its :attr:`~Form.cleaned_data` attribute.
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The whole form, when rendered for the first time, will look like:
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.. code-block:: html+django
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<label for="your_name">Your name: </label>
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<input id="your_name" type="text" name="your_name" maxlength="100" required>
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Note that it **does not** include the ``<form>`` tags, or a submit button.
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We'll have to provide those ourselves in the template.
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.. _using-a-form-in-a-view:
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The view
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~~~~~~~~
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Form data sent back to a Django website is processed by a view, generally the
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same view which published the form. This allows us to reuse some of the same
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logic.
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To handle the form we need to instantiate it in the view for the URL where we
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want it to be published:
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.. code-block:: python
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:caption: ``views.py``
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from django.http import HttpResponseRedirect
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from django.shortcuts import render
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from .forms import NameForm
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def get_name(request):
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# if this is a POST request we need to process the form data
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if request.method == 'POST':
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# create a form instance and populate it with data from the request:
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form = NameForm(request.POST)
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# check whether it's valid:
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if form.is_valid():
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# process the data in form.cleaned_data as required
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# ...
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# redirect to a new URL:
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return HttpResponseRedirect('/thanks/')
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# if a GET (or any other method) we'll create a blank form
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else:
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form = NameForm()
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return render(request, 'name.html', {'form': form})
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If we arrive at this view with a ``GET`` request, it will create an empty form
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instance and place it in the template context to be rendered. This is what we
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can expect to happen the first time we visit the URL.
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If the form is submitted using a ``POST`` request, the view will once again
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create a form instance and populate it with data from the request: ``form =
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NameForm(request.POST)`` This is called "binding data to the form" (it is now
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a *bound* form).
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We call the form's ``is_valid()`` method; if it's not ``True``, we go back to
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the template with the form. This time the form is no longer empty (*unbound*)
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so the HTML form will be populated with the data previously submitted, where it
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can be edited and corrected as required.
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If ``is_valid()`` is ``True``, we'll now be able to find all the validated form
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data in its ``cleaned_data`` attribute. We can use this data to update the
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database or do other processing before sending an HTTP redirect to the browser
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telling it where to go next.
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.. _topics-forms-index-basic-form-template:
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The template
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~~~~~~~~~~~~
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We don't need to do much in our ``name.html`` template:
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.. code-block:: html+django
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<form action="/your-name/" method="post">
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{% csrf_token %}
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{{ form }}
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<input type="submit" value="Submit">
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</form>
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All the form's fields and their attributes will be unpacked into HTML markup
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from that ``{{ form }}`` by Django's template language.
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.. admonition:: Forms and Cross Site Request Forgery protection
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Django ships with an easy-to-use :doc:`protection against Cross Site Request
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Forgeries </ref/csrf>`. When submitting a form via ``POST`` with
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CSRF protection enabled you must use the :ttag:`csrf_token` template tag
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as in the preceding example. However, since CSRF protection is not
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directly tied to forms in templates, this tag is omitted from the
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following examples in this document.
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.. admonition:: HTML5 input types and browser validation
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If your form includes a :class:`~django.forms.URLField`, an
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:class:`~django.forms.EmailField` or any integer field type, Django will
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use the ``url``, ``email`` and ``number`` HTML5 input types. By default,
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browsers may apply their own validation on these fields, which may be
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stricter than Django's validation. If you would like to disable this
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behavior, set the ``novalidate`` attribute on the ``form`` tag, or specify
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a different widget on the field, like :class:`TextInput`.
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We now have a working web form, described by a Django :class:`Form`, processed
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by a view, and rendered as an HTML ``<form>``.
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That's all you need to get started, but the forms framework puts a lot more at
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your fingertips. Once you understand the basics of the process described above,
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you should be prepared to understand other features of the forms system and
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ready to learn a bit more about the underlying machinery.
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More about Django :class:`Form` classes
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=======================================
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All form classes are created as subclasses of either :class:`django.forms.Form`
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or :class:`django.forms.ModelForm`. You can think of ``ModelForm`` as a
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subclass of ``Form``. ``Form`` and ``ModelForm`` actually inherit common
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functionality from a (private) ``BaseForm`` class, but this implementation
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detail is rarely important.
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.. admonition:: Models and Forms
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In fact if your form is going to be used to directly add or edit a Django
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model, a :doc:`ModelForm </topics/forms/modelforms>` can save you a great
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deal of time, effort, and code, because it will build a form, along with the
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appropriate fields and their attributes, from a ``Model`` class.
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Bound and unbound form instances
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--------------------------------
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The distinction between :ref:`ref-forms-api-bound-unbound` is important:
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* An unbound form has no data associated with it. When rendered to the user,
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it will be empty or will contain default values.
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* A bound form has submitted data, and hence can be used to tell if that data
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is valid. If an invalid bound form is rendered, it can include inline error
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messages telling the user what data to correct.
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The form's :attr:`~Form.is_bound` attribute will tell you whether a form has
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data bound to it or not.
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More on fields
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--------------
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Consider a more useful form than our minimal example above, which we could use
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to implement "contact me" functionality on a personal website:
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.. code-block:: python
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:caption: ``forms.py``
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from django import forms
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class ContactForm(forms.Form):
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subject = forms.CharField(max_length=100)
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message = forms.CharField(widget=forms.Textarea)
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sender = forms.EmailField()
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cc_myself = forms.BooleanField(required=False)
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Our earlier form used a single field, ``your_name``, a :class:`CharField`. In
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this case, our form has four fields: ``subject``, ``message``, ``sender`` and
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``cc_myself``. :class:`CharField`, :class:`EmailField` and
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:class:`BooleanField` are just three of the available field types; a full list
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can be found in :doc:`/ref/forms/fields`.
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Widgets
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~~~~~~~
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Each form field has a corresponding :doc:`Widget class </ref/forms/widgets/>`,
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which in turn corresponds to an HTML form widget such as ``<input
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type="text">``.
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In most cases, the field will have a sensible default widget. For example, by
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default, a :class:`CharField` will have a :class:`TextInput` widget, that
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produces an ``<input type="text">`` in the HTML. If you needed ``<textarea>``
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instead, you'd specify the appropriate widget when defining your form field,
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as we have done for the ``message`` field.
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Field data
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~~~~~~~~~~
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Whatever the data submitted with a form, once it has been successfully
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validated by calling ``is_valid()`` (and ``is_valid()`` has returned ``True``),
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the validated form data will be in the ``form.cleaned_data`` dictionary. This
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data will have been nicely converted into Python types for you.
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.. note::
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You can still access the unvalidated data directly from ``request.POST`` at
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this point, but the validated data is better.
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In the contact form example above, ``cc_myself`` will be a boolean value.
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Likewise, fields such as :class:`IntegerField` and :class:`FloatField` convert
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values to a Python ``int`` and ``float`` respectively.
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Here's how the form data could be processed in the view that handles this form:
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.. code-block:: python
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:caption: ``views.py``
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from django.core.mail import send_mail
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if form.is_valid():
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subject = form.cleaned_data['subject']
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message = form.cleaned_data['message']
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sender = form.cleaned_data['sender']
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cc_myself = form.cleaned_data['cc_myself']
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recipients = ['info@example.com']
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if cc_myself:
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recipients.append(sender)
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send_mail(subject, message, sender, recipients)
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return HttpResponseRedirect('/thanks/')
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.. tip::
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For more on sending email from Django, see :doc:`/topics/email`.
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Some field types need some extra handling. For example, files that are uploaded
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using a form need to be handled differently (they can be retrieved from
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``request.FILES``, rather than ``request.POST``). For details of how to handle
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file uploads with your form, see :ref:`binding-uploaded-files`.
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Working with form templates
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===========================
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All you need to do to get your form into a template is to place the form
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instance into the template context. So if your form is called ``form`` in the
|
||
context, ``{{ form }}`` will render its ``<label>`` and ``<input>`` elements
|
||
appropriately.
|
||
|
||
.. admonition:: Additional form template furniture
|
||
|
||
Don't forget that a form's output does *not* include the surrounding
|
||
``<form>`` tags, or the form's ``submit`` control. You will have to provide
|
||
these yourself.
|
||
|
||
Reusable form templates
|
||
-----------------------
|
||
|
||
The HTML output when rendering a form is itself generated via a template. You
|
||
can control this by creating an appropriate template file and setting a custom
|
||
:setting:`FORM_RENDERER` to use that
|
||
:attr:`~django.forms.renderers.BaseRenderer.form_template_name` site-wide. You
|
||
can also customize per-form by overriding the form's
|
||
:attr:`~django.forms.Form.template_name` attribute to render the form using the
|
||
custom template, or by passing the template name directly to
|
||
:meth:`.Form.render`.
|
||
|
||
The example below will result in ``{{ form }}`` being rendered as the output of
|
||
the ``form_snippet.html`` template.
|
||
|
||
In your templates:
|
||
|
||
.. code-block:: html+django
|
||
|
||
# In your template:
|
||
{{ form }}
|
||
|
||
# In form_snippet.html:
|
||
{% for field in form %}
|
||
<div class="fieldWrapper">
|
||
{{ field.errors }}
|
||
{{ field.label_tag }} {{ field }}
|
||
</div>
|
||
{% endfor %}
|
||
|
||
Then you can configure the :setting:`FORM_RENDERER` setting:
|
||
|
||
.. code-block:: python
|
||
:caption: ``settings.py``
|
||
|
||
from django.forms.renderers import TemplatesSetting
|
||
|
||
class CustomFormRenderer(TemplatesSetting):
|
||
form_template_name = "form_snippet.html"
|
||
|
||
FORM_RENDERER = "project.settings.CustomFormRenderer"
|
||
|
||
… or for a single form::
|
||
|
||
class MyForm(forms.Form):
|
||
template_name = "form_snippet.html"
|
||
...
|
||
|
||
… or for a single render of a form instance, passing in the template name to
|
||
the :meth:`.Form.render`. Here's an example of this being used in a view::
|
||
|
||
def index(request):
|
||
form = MyForm()
|
||
rendered_form = form.render("form_snippet.html")
|
||
context = {'form': rendered_form}
|
||
return render(request, 'index.html', context)
|
||
|
||
See :ref:`ref-forms-api-outputting-html` for more details.
|
||
|
||
.. versionchanged:: 4.1
|
||
|
||
The ability to set the default ``form_template_name`` on the form renderer
|
||
was added.
|
||
|
||
Form rendering options
|
||
----------------------
|
||
|
||
There are other output options though for the ``<label>``/``<input>`` pairs:
|
||
|
||
* ``{{ form.as_div }}`` will render them wrapped in ``<div>`` tags.
|
||
|
||
* ``{{ form.as_table }}`` will render them as table cells wrapped in ``<tr>``
|
||
tags.
|
||
|
||
* ``{{ form.as_p }}`` will render them wrapped in ``<p>`` tags.
|
||
|
||
* ``{{ form.as_ul }}`` will render them wrapped in ``<li>`` tags.
|
||
|
||
Note that you'll have to provide the surrounding ``<table>`` or ``<ul>``
|
||
elements yourself.
|
||
|
||
Here's the output of ``{{ form.as_p }}`` for our ``ContactForm`` instance:
|
||
|
||
.. code-block:: html+django
|
||
|
||
<p><label for="id_subject">Subject:</label>
|
||
<input id="id_subject" type="text" name="subject" maxlength="100" required></p>
|
||
<p><label for="id_message">Message:</label>
|
||
<textarea name="message" id="id_message" required></textarea></p>
|
||
<p><label for="id_sender">Sender:</label>
|
||
<input type="email" name="sender" id="id_sender" required></p>
|
||
<p><label for="id_cc_myself">Cc myself:</label>
|
||
<input type="checkbox" name="cc_myself" id="id_cc_myself"></p>
|
||
|
||
Note that each form field has an ID attribute set to ``id_<field-name>``, which
|
||
is referenced by the accompanying label tag. This is important in ensuring that
|
||
forms are accessible to assistive technology such as screen reader software.
|
||
You can also :ref:`customize the way in which labels and ids are generated
|
||
<ref-forms-api-configuring-label>`.
|
||
|
||
See :ref:`ref-forms-api-outputting-html` for more on this.
|
||
|
||
Rendering fields manually
|
||
-------------------------
|
||
|
||
We don't have to let Django unpack the form's fields; we can do it manually if
|
||
we like (allowing us to reorder the fields, for example). Each field is
|
||
available as an attribute of the form using ``{{ form.name_of_field }}``, and
|
||
in a Django template, will be rendered appropriately. For example:
|
||
|
||
.. code-block:: html+django
|
||
|
||
{{ form.non_field_errors }}
|
||
<div class="fieldWrapper">
|
||
{{ form.subject.errors }}
|
||
<label for="{{ form.subject.id_for_label }}">Email subject:</label>
|
||
{{ form.subject }}
|
||
</div>
|
||
<div class="fieldWrapper">
|
||
{{ form.message.errors }}
|
||
<label for="{{ form.message.id_for_label }}">Your message:</label>
|
||
{{ form.message }}
|
||
</div>
|
||
<div class="fieldWrapper">
|
||
{{ form.sender.errors }}
|
||
<label for="{{ form.sender.id_for_label }}">Your email address:</label>
|
||
{{ form.sender }}
|
||
</div>
|
||
<div class="fieldWrapper">
|
||
{{ form.cc_myself.errors }}
|
||
<label for="{{ form.cc_myself.id_for_label }}">CC yourself?</label>
|
||
{{ form.cc_myself }}
|
||
</div>
|
||
|
||
Complete ``<label>`` elements can also be generated using the
|
||
:meth:`~django.forms.BoundField.label_tag`. For example:
|
||
|
||
.. code-block:: html+django
|
||
|
||
<div class="fieldWrapper">
|
||
{{ form.subject.errors }}
|
||
{{ form.subject.label_tag }}
|
||
{{ form.subject }}
|
||
</div>
|
||
|
||
|
||
Rendering form error messages
|
||
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
|
||
|
||
The price of this flexibility is a bit more work. Until now we haven't had to
|
||
worry about how to display form errors, because that's taken care of for us. In
|
||
this example we have had to make sure we take care of any errors for each field
|
||
and any errors for the form as a whole. Note ``{{ form.non_field_errors }}`` at
|
||
the top of the form and the template lookup for errors on each field.
|
||
|
||
Using ``{{ form.name_of_field.errors }}`` displays a list of form errors,
|
||
rendered as an unordered list. This might look like:
|
||
|
||
.. code-block:: html+django
|
||
|
||
<ul class="errorlist">
|
||
<li>Sender is required.</li>
|
||
</ul>
|
||
|
||
The list has a CSS class of ``errorlist`` to allow you to style its appearance.
|
||
If you wish to further customize the display of errors you can do so by looping
|
||
over them:
|
||
|
||
.. code-block:: html+django
|
||
|
||
{% if form.subject.errors %}
|
||
<ol>
|
||
{% for error in form.subject.errors %}
|
||
<li><strong>{{ error|escape }}</strong></li>
|
||
{% endfor %}
|
||
</ol>
|
||
{% endif %}
|
||
|
||
Non-field errors (and/or hidden field errors that are rendered at the top of
|
||
the form when using helpers like ``form.as_p()``) will be rendered with an
|
||
additional class of ``nonfield`` to help distinguish them from field-specific
|
||
errors. For example, ``{{ form.non_field_errors }}`` would look like:
|
||
|
||
.. code-block:: html+django
|
||
|
||
<ul class="errorlist nonfield">
|
||
<li>Generic validation error</li>
|
||
</ul>
|
||
|
||
See :doc:`/ref/forms/api` for more on errors, styling, and working with form
|
||
attributes in templates.
|
||
|
||
Looping over the form's fields
|
||
------------------------------
|
||
|
||
If you're using the same HTML for each of your form fields, you can reduce
|
||
duplicate code by looping through each field in turn using a ``{% for %}``
|
||
loop:
|
||
|
||
.. code-block:: html+django
|
||
|
||
{% for field in form %}
|
||
<div class="fieldWrapper">
|
||
{{ field.errors }}
|
||
{{ field.label_tag }} {{ field }}
|
||
{% if field.help_text %}
|
||
<p class="help">{{ field.help_text|safe }}</p>
|
||
{% endif %}
|
||
</div>
|
||
{% endfor %}
|
||
|
||
Useful attributes on ``{{ field }}`` include:
|
||
|
||
``{{ field.errors }}``
|
||
Outputs a ``<ul class="errorlist">`` containing any validation errors
|
||
corresponding to this field. You can customize the presentation of
|
||
the errors with a ``{% for error in field.errors %}`` loop. In this
|
||
case, each object in the loop is a string containing the error message.
|
||
|
||
``{{ field.field }}``
|
||
The :class:`~django.forms.Field` instance from the form class that
|
||
this :class:`~django.forms.BoundField` wraps. You can use it to access
|
||
:class:`~django.forms.Field` attributes, e.g.
|
||
``{{ char_field.field.max_length }}``.
|
||
|
||
``{{ field.help_text }}``
|
||
Any help text that has been associated with the field.
|
||
|
||
``{{ field.html_name }}``
|
||
The name of the field that will be used in the input element's name
|
||
field. This takes the form prefix into account, if it has been set.
|
||
|
||
``{{ field.id_for_label }}``
|
||
The ID that will be used for this field (``id_email`` in the example
|
||
above). If you are constructing the label manually, you may want to use
|
||
this in lieu of ``label_tag``. It's also useful, for example, if you have
|
||
some inline JavaScript and want to avoid hardcoding the field's ID.
|
||
|
||
``{{ field.is_hidden }}``
|
||
This attribute is ``True`` if the form field is a hidden field and
|
||
``False`` otherwise. It's not particularly useful as a template
|
||
variable, but could be useful in conditional tests such as:
|
||
|
||
.. code-block:: html+django
|
||
|
||
{% if field.is_hidden %}
|
||
{# Do something special #}
|
||
{% endif %}
|
||
|
||
``{{ field.label }}``
|
||
The label of the field, e.g. ``Email address``.
|
||
|
||
``{{ field.label_tag }}``
|
||
The field's label wrapped in the appropriate HTML ``<label>`` tag. This
|
||
includes the form's :attr:`~django.forms.Form.label_suffix`. For example,
|
||
the default ``label_suffix`` is a colon::
|
||
|
||
<label for="id_email">Email address:</label>
|
||
|
||
``{{ field.legend_tag }}``
|
||
|
||
.. versionadded:: 4.1
|
||
|
||
Similar to ``field.label_tag`` but uses a ``<legend>`` tag in place of
|
||
``<label>``, for widgets with multiple inputs wrapped in a ``<fieldset>``.
|
||
|
||
``{{ field.use_fieldset }}``
|
||
|
||
.. versionadded:: 4.1
|
||
|
||
This attribute is ``True`` if the form field's widget contains multiple
|
||
inputs that should be semantically grouped in a ``<fieldset>`` with a
|
||
``<legend>`` to improve accessibility. An example use in a template:
|
||
|
||
.. code-block:: html+django
|
||
|
||
{% if field.use_fieldset %}
|
||
<fieldset>
|
||
{% if field.label %}{{ field.legend_tag }}{% endif %}
|
||
{% else %}
|
||
{% if field.label %}{{ field.label_tag }}{% endif %}
|
||
{% endif %}
|
||
{{ field }}
|
||
{% if field.use_fieldset %}</fieldset>{% endif %}
|
||
|
||
``{{ field.value }}``
|
||
The value of the field. e.g ``someone@example.com``.
|
||
|
||
.. seealso::
|
||
|
||
For a complete list of attributes and methods, see
|
||
:class:`~django.forms.BoundField`.
|
||
|
||
Looping over hidden and visible fields
|
||
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
|
||
|
||
If you're manually laying out a form in a template, as opposed to relying on
|
||
Django's default form layout, you might want to treat ``<input type="hidden">``
|
||
fields differently from non-hidden fields. For example, because hidden fields
|
||
don't display anything, putting error messages "next to" the field could cause
|
||
confusion for your users -- so errors for those fields should be handled
|
||
differently.
|
||
|
||
Django provides two methods on a form that allow you to loop over the hidden
|
||
and visible fields independently: ``hidden_fields()`` and
|
||
``visible_fields()``. Here's a modification of an earlier example that uses
|
||
these two methods:
|
||
|
||
.. code-block:: html+django
|
||
|
||
{# Include the hidden fields #}
|
||
{% for hidden in form.hidden_fields %}
|
||
{{ hidden }}
|
||
{% endfor %}
|
||
{# Include the visible fields #}
|
||
{% for field in form.visible_fields %}
|
||
<div class="fieldWrapper">
|
||
{{ field.errors }}
|
||
{{ field.label_tag }} {{ field }}
|
||
</div>
|
||
{% endfor %}
|
||
|
||
This example does not handle any errors in the hidden fields. Usually, an
|
||
error in a hidden field is a sign of form tampering, since normal form
|
||
interaction won't alter them. However, you could easily insert some error
|
||
displays for those form errors, as well.
|
||
|
||
Further topics
|
||
==============
|
||
|
||
This covers the basics, but forms can do a whole lot more:
|
||
|
||
.. toctree::
|
||
:maxdepth: 2
|
||
|
||
formsets
|
||
modelforms
|
||
media
|
||
|
||
.. seealso::
|
||
|
||
:doc:`The Forms Reference </ref/forms/index>`
|
||
Covers the full API reference, including form fields, form widgets,
|
||
and form and field validation.
|