The form rendering API¶
In older versions, widgets are rendered using Python. All APIs described in this document are new.
Django’s form widgets are rendered using Django’s template engines system.
The form rendering process can be customized at several levels:
- Widgets can specify custom template names.
- Forms and widgets can specify custom renderer classes.
- A widget’s template can be overridden by a project. (Reusable applications typically shouldn’t override built-in templates because they might conflict with a project’s custom templates.)
The low-level render API¶
The rendering of form templates is controlled by a customizable renderer class.
A custom renderer can be specified by updating the FORM_RENDERER
setting. It defaults to
'
django.forms.renderers.DjangoTemplates
'
.
You can also provide a custom renderer by setting the
Form.default_renderer
attribute or by using the renderer
argument
of Widget.render()
.
Use one of the built-in template form renderers or implement your own. Custom renderers
must implement a render(template_name, context, request=None)
method. It
should return a rendered templates (as a string) or raise
TemplateDoesNotExist
.
Built-in-template form renderers¶
DjangoTemplates
¶
This renderer uses a standalone
DjangoTemplates
engine (unconnected to what you might have configured in the
TEMPLATES
setting). It loads templates first from the built-in form
templates directory in django/forms/templates
and then from the installed
apps’ templates directories using the app_directories
loader.
If you want to render templates with customizations from your
TEMPLATES
setting, such as context processors for example, use the
TemplatesSetting
renderer.
Jinja2
¶
This renderer is the same as the DjangoTemplates
renderer except that
it uses a Jinja2
backend. Templates
for the built-in widgets are located in django/forms/jinja2
and installed
apps can provide templates in a jinja2
directory.
To use this backend, all the widgets in your project and its third-party apps
must have Jinja2 templates. Unless you provide your own Jinja2 templates for
widgets that don’t have any, you can’t use this renderer. For example,
django.contrib.admin
doesn’t include Jinja2 templates for its widgets
due to their usage of Django template tags.
TemplatesSetting
¶
This renderer gives you complete control of how widget templates are sourced.
It uses get_template()
to find widget
templates based on what’s configured in the TEMPLATES
setting.
Using this renderer along with the built-in widget templates requires either:
'django.forms'
inINSTALLED_APPS
and at least one engine withAPP_DIRS=True
.Adding the built-in widgets templates directory in
DIRS
of one of your template engines. To generate that path:import django django.__path__[0] + '/forms/templates' # or '/forms/jinja2'
Using this renderer requires you to make sure the form templates your project needs can be located.
Context available in widget templates¶
Widget templates receive a context from Widget.get_context()
. By
default, widgets receive a single value in the context, widget
. This is a
dictionary that contains values like:
name
value
attrs
is_hidden
template_name
Some widgets add further information to the context. For instance, all widgets
that subclass Input
defines widget['type']
and MultiWidget
defines widget['subwidgets']
for looping purposes.
Overriding built-in widget templates¶
Each widget has a template_name
attribute with a value such as
input.html
. Built-in widget templates are stored in the
django/forms/widgets
path. You can provide a custom template for
input.html
by defining django/forms/widgets/input.html
, for example.
See Built-in widgets for the name of each widget’s template.
If you use the TemplatesSetting
renderer, overriding widget templates
works the same as overriding any other template in your project. You can’t
override built-in widget templates using the other built-in renderers.