>>> from django import forms
>>> f = forms.EmailField()
>>> f.clean("[email protected]")
'[email protected]'
>>> f.clean("invalid email address")
Traceback (most recent call last):
ValidationError: ['Enter a valid email address.']
Core field arguments
Each Field class constructor takes at least these arguments. Some
Field classes take additional, field-specific arguments, but the following
should always be accepted:
required
Field.required
By default, each Field class assumes the value is required, so if you pass
an empty value – either None or the empty string ("") – then
clean() will raise a ValidationError exception:
>>> from django import forms
>>> f = forms.CharField()
>>> f.clean("foo")
'foo'
>>> f.clean("")
Traceback (most recent call last):
ValidationError: ['This field is required.']
>>> f.clean(None)
Traceback (most recent call last):
ValidationError: ['This field is required.']
>>> f.clean(" ")
>>> f.clean(0)
>>> f.clean(True)
'True'
>>> f.clean(False)
'False'
To specify that a field is not required, pass required=False to the
Field constructor:
>>> f = forms.CharField(required=False)
>>> f.clean("foo")
'foo'
>>> f.clean("")
>>> f.clean(None)
>>> f.clean(0)
>>> f.clean(True)
'True'
>>> f.clean(False)
'False'
If a Field has required=False and you pass clean() an empty value,
then clean() will return a normalized empty value rather than raising
ValidationError. For CharField, this will return
empty_value which defaults to an empty string. For other
Field classes, it might be None. (This varies from field to field.)
Widgets of required form fields have the required HTML attribute. Set the
Form.use_required_attribute attribute to False to disable it. The
required attribute isn’t included on forms of formsets because the browser
validation may not be correct when adding and deleting formsets.
label
Field.label
The label argument lets you specify the “human-friendly” label for this
field. This is used when the Field is displayed in a Form.
As explained in “Outputting forms as HTML” above, the default label for a
Field is generated from the field name by converting all underscores to
spaces and upper-casing the first letter. Specify label if that default
behavior doesn’t result in an adequate label.
Here’s a full example Form that implements label for two of its fields.
We’ve specified auto_id=False to simplify the output:
>>> from django import forms
>>> class CommentForm(forms.Form):
... name = forms.CharField(label="Your name")
... url = forms.URLField(label="Your website", required=False)
... comment = forms.CharField()
>>> f = CommentForm(auto_id=False)
>>> print(f)
<div>Your name:<input type="text" name="name" required></div>
<div>Your website:<input type="url" name="url"></div>
<div>Comment:<input type="text" name="comment" required></div>
The label_suffix argument lets you override the form’s
label_suffix on a per-field basis:
>>> class ContactForm(forms.Form):
... age = forms.IntegerField()
... nationality = forms.CharField()
... captcha_answer = forms.IntegerField(label="2 + 2", label_suffix=" =")
>>> f = ContactForm(label_suffix="?")
>>> print(f)
<div><label for="id_age">Age?</label><input type="number" name="age" required id="id_age"></div>
<div><label for="id_nationality">Nationality?</label><input type="text" name="nationality" required id="id_nationality"></div>
<div><label for="id_captcha_answer">2 + 2 =</label><input type="number" name="captcha_answer" required id="id_captcha_answer"></div>
The initial argument lets you specify the initial value to use when
rendering this Field in an unbound Form.
To specify dynamic initial data, see the Form.initial parameter.
The use-case for this is when you want to display an “empty” form in which a
field is initialized to a particular value. For example:
>>> from django import forms
>>> class CommentForm(forms.Form):
... name = forms.CharField(initial="Your name")
... url = forms.URLField(initial="https://")
... comment = forms.CharField()
>>> f = CommentForm(auto_id=False)
>>> print(f)
<div>Name:<input type="text" name="name" value="Your name" required></div>
<div>Url:<input type="url" name="url" value="https://" required></div>
<div>Comment:<input type="text" name="comment" required></div>
You may be thinking, why not just pass a dictionary of the initial values as
data when displaying the form? Well, if you do that, you’ll trigger validation,
and the HTML output will include any validation errors:
>>> class CommentForm(forms.Form):
... name = forms.CharField()
... url = forms.URLField()
... comment = forms.CharField()
>>> default_data = {"name": "Your name", "url": "https://"}
>>> f = CommentForm(default_data, auto_id=False)
>>> print(f)
<div>Name:
<input type="text" name="name" value="Your name" required>
<div>Url:
<ul class="errorlist"><li>Enter a valid URL.</li></ul>
<input type="url" name="url" value="https://" required aria-invalid="true">
<div>Comment:
<ul class="errorlist"><li>This field is required.</li></ul>
<input type="text" name="comment" required aria-invalid="true">
This is why initial values are only displayed for unbound forms. For bound
forms, the HTML output will use the bound data.
Also note that initial values are not used as “fallback” data in
validation if a particular field’s value is not given. initial values are
only intended for initial form display:
>>> class CommentForm(forms.Form):
... name = forms.CharField(initial="Your name")
... url = forms.URLField(initial="https://")
... comment = forms.CharField()
>>> data = {"name": "", "url": "", "comment": "Foo"}
>>> f = CommentForm(data)
>>> f.is_valid()
False
# The form does *not* fall back to using the initial values.
>>> f.errors
{'url': ['This field is required.'], 'name': ['This field is required.']}
Instead of a constant, you can also pass any callable:
>>> import datetime
>>> class DateForm(forms.Form):
... day = forms.DateField(initial=datetime.date.today)
>>> print(DateForm())
<div><label for="id_day">Day:</label><input type="text" name="day" value="2023-02-11" required id="id_day"></div>
The callable will be evaluated only when the unbound form is displayed, not when it is defined.
widget
Field.widget
The widget argument lets you specify a Widget class to use when
rendering this Field. See Widgets for more information.
help_text
Field.help_text
The help_text argument lets you specify descriptive text for this
Field. If you provide help_text, it will be displayed next to the
Field when the Field is rendered by one of the convenience Form
methods (e.g., as_ul()).
Like the model field’s help_text, this value
isn’t HTML-escaped in automatically-generated forms.
Here’s a full example Form that implements help_text for two of its
fields. We’ve specified auto_id=False to simplify the output:
>>> from django import forms
>>> class HelpTextContactForm(forms.Form):
... subject = forms.CharField(max_length=100, help_text="100 characters max.")
... message = forms.CharField()
... sender = forms.EmailField(help_text="A valid email address, please.")
... cc_myself = forms.BooleanField(required=False)
>>> f = HelpTextContactForm(auto_id=False)
>>> print(f)
<div>Subject:<div class="helptext">100 characters max.</div><input type="text" name="subject" maxlength="100" required></div>
<div>Message:<input type="text" name="message" required></div>
<div>Sender:<div class="helptext">A valid email address, please.</div><input type="email" name="sender" required></div>
<div>Cc myself:<input type="checkbox" name="cc_myself"></div>
When a field has help text it is associated with its input using the
aria-describedby HTML attribute. If the widget is rendered in a
<fieldset> then aria-describedby is added to this element, otherwise it
is added to the widget’s <input>:
>>> from django import forms
>>> class UserForm(forms.Form):
... username = forms.CharField(max_length=255, help_text="e.g., [email protected]")
>>> f = UserForm()
>>> print(f)
<label for="id_username">Username:</label>
<div class="helptext" id="id_username_helptext">e.g., [email protected]</div>
<input type="text" name="username" maxlength="255" required aria-describedby="id_username_helptext" id="id_username">
When adding a custom aria-describedby attribute, make sure to also include
the id of the help_text element (if used) in the desired order. For
screen reader users, descriptions will be read in their order of appearance
inside aria-describedby:
>>> class UserForm(forms.Form):
... username = forms.CharField(
... max_length=255,
... help_text="e.g., [email protected]",
... widget=forms.TextInput(
... attrs={"aria-describedby": "custom-description id_username_helptext"},
... ),
... )
>>> f = UserForm()
>>> print(f["username"])
<input type="text" name="username" aria-describedby="custom-description id_username_helptext" maxlength="255" id="id_username" required>
Changed in Django 5.0: aria-describedby was added to associate help_text with its input.
Changed in Django 5.1: aria-describedby support was added for <fieldset>.
error_messages
Field.error_messages
The error_messages argument lets you override the default messages that the
field will raise. Pass in a dictionary with keys matching the error messages you
want to override. For example, here is the default error message:
>>> from django import forms
>>> generic = forms.CharField()
>>> generic.clean("")
Traceback (most recent call last):
ValidationError: ['This field is required.']
And here is a custom error message:
>>> name = forms.CharField(error_messages={"required": "Please enter your name"})
>>> name.clean("")
Traceback (most recent call last):
ValidationError: ['Please enter your name']
In the built-in Field classes section below, each Field defines the
error message keys it uses.
validators
Field.validators
The validators argument lets you provide a list of validation functions
for this field.
See the validators documentation for more information.
localize
Field.localize
The localize argument enables the localization of form data input, as well
as the rendered output.
See the format localization documentation for
more information.
disabled
Field.disabled
The disabled boolean argument, when set to True, disables a form field
using the disabled HTML attribute so that it won’t be editable by users.
Even if a user tampers with the field’s value submitted to the server, it will
be ignored in favor of the value from the form’s initial data.
template_name
Field.template_name
New in Django 5.0.
The template_name argument allows a custom template to be used when the
field is rendered with as_field_group(). By
default this value is set to "django/forms/field.html". Can be changed per
field by overriding this attribute or more generally by overriding the default
template, see also Overriding built-in field templates.
Checking if the field data has changed
has_changed()
Field.has_changed()[source]
The has_changed() method is used to determine if the field value has changed
from the initial value. Returns True or False.
See the Form.has_changed() documentation for more information.
Built-in Field classes
Naturally, the forms library comes with a set of Field classes that
represent common validation needs. This section documents each built-in field.
For each field, we describe the default widget used if you don’t specify
widget. We also specify the value returned when you provide an empty value
(see the section on required above to understand what that means).
BooleanField
class BooleanField(**kwargs)[source]
Default widget: CheckboxInput
Empty value: False
Normalizes to: A Python True or False value.
Validates that the value is True (e.g. the check box is checked) if
the field has required=True.
Error message keys: required
Since all Field subclasses have required=True by default, the
validation condition here is important. If you want to include a boolean
in your form that can be either True or False (e.g. a checked or
unchecked checkbox), you must remember to pass in required=False when
creating the BooleanField.
Default widget: TextInput
Empty value: Whatever you’ve given as empty_value.
Normalizes to: A string.
Uses MaxLengthValidator and
MinLengthValidator if max_length and
min_length are provided. Otherwise, all inputs are valid.
Error message keys: required, max_length, min_length
Has the following optional arguments for validation:
max_length
Empty value: '' (an empty string)
Normalizes to: A string.
Validates that the given value exists in the list of choices.
Error message keys: required, invalid_choice
The invalid_choice error message may contain %(value)s, which will be
replaced with the selected choice.
Takes one extra argument:
choices[source]
Either an iterable of 2-tuples to use as choices for this
field, enumeration type, or a
callable that returns such an iterable. This argument accepts the same
formats as the choices argument to a model field. See the
model field reference documentation on choices
for more details. If the argument is a callable, it is evaluated each
time the field’s form is initialized, in addition to during rendering.
Defaults to an empty list.
Choice type
This field normalizes choices to strings, so if choices are required in
other data types, such as integers or booleans, consider using
TypedChoiceField instead.
Changed in Django 5.0: Support for mappings and using
enumeration types directly in
choices was added.
Empty value: None
Normalizes to: A Python datetime.date object.
Validates that the given value is either a datetime.date,
datetime.datetime or string formatted in a particular date format.
Error message keys: required, invalid
Takes one optional argument:
input_formats
An iterable of formats used to attempt to convert a string to a valid
datetime.date object.
If no input_formats argument is provided, the default input formats are
taken from the active locale format DATE_INPUT_FORMATS key, or from
DATE_INPUT_FORMATS if localization is disabled. See also
format localization.
Default widget: DateTimeInput
Empty value: None
Normalizes to: A Python datetime.datetime object.
Validates that the given value is either a datetime.datetime,
datetime.date or string formatted in a particular datetime format.
Error message keys: required, invalid
Takes one optional argument:
input_formats
An iterable of formats used to attempt to convert a string to a valid
datetime.datetime object, in addition to ISO 8601 formats.
The field always accepts strings in ISO 8601 formatted dates or similar
recognized by parse_datetime(). Some examples
'2006-10-25 14:30:59'
'2006-10-25T14:30:59'
'2006-10-25 14:30'
'2006-10-25T14:30'
'2006-10-25T14:30Z'
'2006-10-25T14:30+02:00'
'2006-10-25'
If no input_formats argument is provided, the default input formats are
taken from the active locale format DATETIME_INPUT_FORMATS and
DATE_INPUT_FORMATS keys, or from DATETIME_INPUT_FORMATS and
DATE_INPUT_FORMATS if localization is disabled. See also
format localization.
class DecimalField(**kwargs)[source]
Default widget: NumberInput when Field.localize is
False, else TextInput.
Empty value: None
Normalizes to: A Python decimal.
Validates that the given value is a decimal. Uses
MaxValueValidator and
MinValueValidator if max_value and
min_value are provided. Uses
StepValueValidator if step_size is
provided. Leading and trailing whitespace is ignored.
Error message keys: required, invalid, max_value,
min_value, max_digits, max_decimal_places,
max_whole_digits, step_size.
The max_value and min_value error messages may contain
%(limit_value)s, which will be substituted by the appropriate limit.
Similarly, the max_digits, max_decimal_places and
max_whole_digits error messages may contain %(max)s.
Takes five optional arguments:
max_value
max_digits
The maximum number of digits (those before the decimal point plus those
after the decimal point, with leading zeros stripped) permitted in the
value.
step_size
Limit valid inputs to an integral multiple of step_size. If
min_value is also provided, it’s added as an offset to determine if
the step size matches.
Empty value: None
Normalizes to: A Python timedelta.
Validates that the given value is a string which can be converted into a
timedelta. The value must be between datetime.timedelta.min
and datetime.timedelta.max.
Error message keys: required, invalid, overflow.
Accepts any format understood by
parse_duration().
Default widget: EmailInput
Empty value: Whatever you’ve given as empty_value.
Normalizes to: A string.
Uses EmailValidator to validate that
the given value is a valid email address, using a moderately complex
regular expression.
Error message keys: required, invalid
Has the optional arguments max_length, min_length, and
empty_value which work just as they do for CharField. The
max_length argument defaults to 320 (see RFC 3696#section-3).
Default widget: ClearableFileInput
Empty value: None
Normalizes to: An UploadedFile object that wraps the file content
and file name into a single object.
Can validate that non-empty file data has been bound to the form.
Error message keys: required, invalid, missing, empty,
max_length
Has the optional arguments for validation: max_length and
allow_empty_file. If provided, these ensure that the file name is at
most the given length, and that validation will succeed even if the file
content is empty.
To learn more about the UploadedFile object, see the file uploads
documentation.
When you use a FileField in a form, you must also remember to
bind the file data to the form.
The max_length error refers to the length of the filename. In the error
message for that key, %(max)d will be replaced with the maximum filename
length and %(length)d will be replaced with the current filename length.
Empty value: '' (an empty string)
Normalizes to: A string.
Validates that the selected choice exists in the list of choices.
Error message keys: required, invalid_choice
The field allows choosing from files inside a certain directory. It takes five
extra arguments; only path is required:
path
The absolute path to the directory whose contents you want listed. This
directory must exist.
recursive
If False (the default) only the direct contents of path will be
offered as choices. If True, the directory will be descended into
recursively and all descendants will be listed as choices.
allow_files
Optional. Either True or False. Default is True. Specifies
whether files in the specified location should be included. Either this or
allow_folders must be True.
allow_folders
Optional. Either True or False. Default is False. Specifies
whether folders in the specified location should be included. Either this or
allow_files must be True.
class FloatField(**kwargs)[source]
Default widget: NumberInput when Field.localize is
False, else TextInput.
Empty value: None
Normalizes to: A Python float.
Validates that the given value is a float. Uses
MaxValueValidator and
MinValueValidator if max_value and
min_value are provided. Uses
StepValueValidator if step_size is
provided. Leading and trailing whitespace is allowed, as in Python’s
float() function.
Error message keys: required, invalid, max_value,
min_value, step_size.
Takes three optional arguments:
max_value
step_size
Limit valid inputs to an integral multiple of step_size. If
min_value is also provided, it’s added as an offset to determine if
the step size matches.
class GenericIPAddressField(**kwargs)[source]
A field containing either an IPv4 or an IPv6 address.
Default widget: TextInput
Empty value: '' (an empty string)
Normalizes to: A string. IPv6 addresses are normalized as described below.
Validates that the given value is a valid IP address.
Error message keys: required, invalid
The IPv6 address normalization follows RFC 4291#section-2.2 section 2.2,
including using the IPv4 format suggested in paragraph 3 of that section, like
::ffff:192.0.2.0. For example, 2001:0::0:01 would be normalized to
2001::1, and ::ffff:0a0a:0a0a to ::ffff:10.10.10.10. All characters
are converted to lowercase.
Takes two optional arguments:
protocol
Limits valid inputs to the specified protocol.
Accepted values are both (default), IPv4
or IPv6. Matching is case insensitive.
unpack_ipv4
Unpacks IPv4 mapped addresses like ::ffff:192.0.2.1.
If this option is enabled that address would be unpacked to
192.0.2.1. Default is disabled. Can only be used
when protocol is set to 'both'.
Default widget: ClearableFileInput
Empty value: None
Normalizes to: An UploadedFile object that wraps the file content
and file name into a single object.
Validates that file data has been bound to the form. Also uses
FileExtensionValidator to validate that
the file extension is supported by Pillow.
Error message keys: required, invalid, missing, empty,
invalid_image
Using an ImageField requires that pillow is installed with
support for the image formats you use. If you encounter a corrupt image
error when you upload an image, it usually means that Pillow doesn’t
understand its format. To fix this, install the appropriate library and
reinstall Pillow.
When you use an ImageField on a form, you must also remember to
bind the file data to the form.
After the field has been cleaned and validated, the UploadedFile
object will have an additional image attribute containing the Pillow
Image instance used to check if the file was a valid image. Pillow
closes the underlying file descriptor after verifying an image, so while
non-image data attributes, such as format, height, and width,
are available, methods that access the underlying image data, such as
getdata() or getpixel(), cannot be used without reopening the file.
For example:
>>> from PIL import Image
>>> from django import forms
>>> from django.core.files.uploadedfile import SimpleUploadedFile
>>> class ImageForm(forms.Form):
... img = forms.ImageField()
>>> file_data = {"img": SimpleUploadedFile("test.png", b"file data")}
>>> form = ImageForm({}, file_data)
# Pillow closes the underlying file descriptor.
>>> form.is_valid()
>>> image_field = form.cleaned_data["img"]
>>> image_field.image
<PIL.PngImagePlugin.PngImageFile image mode=RGBA size=191x287 at 0x7F5985045C18>
>>> image_field.image.width
>>> image_field.image.height
>>> image_field.image.format
'PNG'
>>> image_field.image.getdata()
# Raises AttributeError: 'NoneType' object has no attribute 'seek'.
>>> image = Image.open(image_field)
>>> image.getdata()
<ImagingCore object at 0x7f5984f874b0>
Additionally, UploadedFile.content_type will be updated with the
image’s content type if Pillow can determine it, otherwise it will be set
to None.
class IntegerField(**kwargs)[source]
Default widget: NumberInput when Field.localize is
False, else TextInput.
Empty value: None
Normalizes to: A Python integer.
Validates that the given value is an integer. Uses
MaxValueValidator and
MinValueValidator if max_value and
min_value are provided. Uses
StepValueValidator if step_size is
provided. Leading and trailing whitespace is allowed, as in Python’s
int() function.
Error message keys: required, invalid, max_value,
min_value, step_size
The max_value, min_value and step_size error messages may
contain %(limit_value)s, which will be substituted by the appropriate
limit.
Takes three optional arguments for validation:
max_value
step_size
Limit valid inputs to an integral multiple of step_size. If
min_value is also provided, it’s added as an offset to determine if
the step size matches.
class JSONField(encoder=None, decoder=None, **kwargs)[source]
A field which accepts JSON encoded data for a
JSONField.
Default widget: Textarea
Empty value: None
Normalizes to: A Python representation of the JSON value (usually as a
dict, list, or None), depending on JSONField.decoder.
Validates that the given value is a valid JSON.
Error message keys: required, invalid
Takes two optional arguments:
encoder
A json.JSONEncoder subclass to serialize data types not
supported by the standard JSON serializer (e.g. datetime.datetime
or UUID). For example, you can use the
DjangoJSONEncoder class.
Defaults to json.JSONEncoder.
decoder
A json.JSONDecoder subclass to deserialize the input. Your
deserialization may need to account for the fact that you can’t be
certain of the input type. For example, you run the risk of returning a
datetime that was actually a string that just happened to be in the
same format chosen for datetimes.
The decoder can be used to validate the input. If
json.JSONDecodeError is raised during the deserialization,
a ValidationError will be raised.
Defaults to json.JSONDecoder.
If you use a ModelForm, the
encoder and decoder from JSONField
will be used.
User friendly forms
JSONField is not particularly user friendly in most cases. However,
it is a useful way to format data from a client-side widget for
submission to the server.
Default widget: SelectMultiple
Empty value: [] (an empty list)
Normalizes to: A list of strings.
Validates that every value in the given list of values exists in the list
of choices.
Error message keys: required, invalid_choice, invalid_list
The invalid_choice error message may contain %(value)s, which will be
replaced with the selected choice.
Takes one extra required argument, choices, as for ChoiceField.
Default widget: NullBooleanSelect
Empty value: None
Normalizes to: A Python True, False or None value.
Validates nothing (i.e., it never raises a ValidationError).
NullBooleanField may be used with widgets such as
Select or RadioSelect
by providing the widget choices:
NullBooleanField(
widget=Select(
choices=[
("", "Unknown"),
(True, "Yes"),
(False, "No"),
Default widget: TextInput
Empty value: Whatever you’ve given as empty_value.
Normalizes to: A string.
Uses RegexValidator to validate that
the given value matches a certain regular expression.
Error message keys: required, invalid
Takes one required argument:
regex
A regular expression specified either as a string or a compiled regular
expression object.
Also takes max_length, min_length, strip, and empty_value
which work just as they do for CharField.
strip
Defaults to False. If enabled, stripping will be applied before the
regex validation.
Default widget: TextInput
Empty value: Whatever you’ve given as empty_value.
Normalizes to: A string.
Uses validate_slug or
validate_unicode_slug to validate that
the given value contains only letters, numbers, underscores, and hyphens.
Error messages: required, invalid
This field is intended for use in representing a model
SlugField in forms.
Takes two optional parameters:
allow_unicode
A boolean instructing the field to accept Unicode letters in addition
to ASCII letters. Defaults to False.
Empty value: None
Normalizes to: A Python datetime.time object.
Validates that the given value is either a datetime.time or string
formatted in a particular time format.
Error message keys: required, invalid
Takes one optional argument:
input_formats
An iterable of formats used to attempt to convert a string to a valid
datetime.time object.
If no input_formats argument is provided, the default input formats are
taken from the active locale format TIME_INPUT_FORMATS key, or from
TIME_INPUT_FORMATS if localization is disabled. See also
format localization.
class TypedChoiceField(**kwargs)[source]
Just like a ChoiceField, except TypedChoiceField takes two
extra arguments, coerce and empty_value.
Default widget: Select
Empty value: Whatever you’ve given as empty_value.
Normalizes to: A value of the type provided by the coerce
argument.
Validates that the given value exists in the list of choices and can be
coerced.
Error message keys: required, invalid_choice
Takes extra arguments:
coerce
A function that takes one argument and returns a coerced value. Examples
include the built-in int, float, bool and other types. Defaults
to an identity function. Note that coercion happens after input
validation, so it is possible to coerce to a value not present in
choices.
empty_value
The value to use to represent “empty.” Defaults to the empty string;
None is another common choice here. Note that this value will not be
coerced by the function given in the coerce argument, so choose it
accordingly.
class TypedMultipleChoiceField(**kwargs)[source]
Just like a MultipleChoiceField, except TypedMultipleChoiceField
takes two extra arguments, coerce and empty_value.
Default widget: SelectMultiple
Empty value: Whatever you’ve given as empty_value
Normalizes to: A list of values of the type provided by the coerce
argument.
Validates that the given values exists in the list of choices and can be
coerced.
Error message keys: required, invalid_choice
The invalid_choice error message may contain %(value)s, which will be
replaced with the selected choice.
Takes two extra arguments, coerce and empty_value, as for
TypedChoiceField.
Default widget: URLInput
Empty value: Whatever you’ve given as empty_value.
Normalizes to: A string.
Uses URLValidator to validate that the
given value is a valid URL.
Error message keys: required, invalid
Has the optional arguments max_length, min_length, empty_value
which work just as they do for CharField, and one more argument:
assume_scheme
New in Django 5.0.
The scheme assumed for URLs provided without one. Defaults to
"http". For example, if assume_scheme is "https" and the
provided value is "example.com", the normalized value will be
"https://example.com".
Deprecated since version 5.0: The default value for assume_scheme will change from "http" to
"https" in Django 6.0. Set FORMS_URLFIELD_ASSUME_HTTPS
transitional setting to True to opt into using "https" during
the Django 5.x release cycle.
Error message keys: required, invalid
This field will accept any string format accepted as the hex argument
to the UUID constructor.
Empty value: '' (an empty string)
Normalizes to: A string.
Validates the given value against each of the fields specified
as an argument to the ComboField.
Error message keys: required, invalid
Takes one extra required argument:
fields
The list of fields that should be used to validate the field’s value (in
the order in which they are provided).
>>> from django.forms import ComboField
>>> f = ComboField(fields=[CharField(max_length=20), EmailField()])
>>> f.clean("[email protected]")
'[email protected]'
>>> f.clean("[email protected]")
Traceback (most recent call last):
ValidationError: ['Ensure this value has at most 20 characters (it has 28).']
Default widget: TextInput
Empty value: '' (an empty string)
Normalizes to: the type returned by the compress method of the subclass.
Validates the given value against each of the fields specified
as an argument to the MultiValueField.
Error message keys: required, invalid, incomplete
Aggregates the logic of multiple fields that together produce a single
value.
This field is abstract and must be subclassed. In contrast with the
single-value fields, subclasses of MultiValueField must not
implement clean() but instead - implement
compress().
Takes one extra required argument:
fields
A tuple of fields whose values are cleaned and subsequently combined
into a single value. Each value of the field is cleaned by the
corresponding field in fields – the first value is cleaned by the
first field, the second value is cleaned by the second field, etc.
Once all fields are cleaned, the list of clean values is combined into
a single value by compress().
Also takes some optional arguments:
require_all_fields
Defaults to True, in which case a required validation error
will be raised if no value is supplied for any field.
When set to False, the Field.required attribute can be set
to False for individual fields to make them optional. If no value
is supplied for a required field, an incomplete validation error
will be raised.
A default incomplete error message can be defined on the
MultiValueField subclass, or different messages can be defined
on each individual field. For example:
from django.core.validators import RegexValidator
class PhoneField(MultiValueField):
def __init__(self, **kwargs):
# Define one message for all fields.
error_messages = {
"incomplete": "Enter a country calling code and a phone number.",
# Or define a different message for each field.
fields = (
CharField(
error_messages={"incomplete": "Enter a country calling code."},
validators=[
RegexValidator(r"^[0-9]+$", "Enter a valid country calling code."),
CharField(
error_messages={"incomplete": "Enter a phone number."},
validators=[RegexValidator(r"^[0-9]+$", "Enter a valid phone number.")],
CharField(
validators=[RegexValidator(r"^[0-9]+$", "Enter a valid extension.")],
required=False,
super().__init__(
error_messages=error_messages,
fields=fields,
require_all_fields=False,
**kwargs
widget
Must be a subclass of django.forms.MultiWidget.
Default value is TextInput, which
probably is not very useful in this case.
compress(data_list)[source]
Takes a list of valid values and returns a “compressed” version of
those values – in a single value. For example,
SplitDateTimeField is a subclass which combines a time field
and a date field into a datetime object.
This method must be implemented in the subclasses.
Default widget: SplitDateTimeWidget
Empty value: None
Normalizes to: A Python datetime.datetime object.
Validates that the given value is a datetime.datetime or string
formatted in a particular datetime format.
Error message keys: required, invalid, invalid_date,
invalid_time
Takes two optional arguments:
input_date_formats
A list of formats used to attempt to convert a string to a valid
datetime.date object.
If no input_date_formats argument is provided, the default input formats
for DateField are used.
input_time_formats
A list of formats used to attempt to convert a string to a valid
datetime.time object.
If no input_time_formats argument is provided, the default input formats
for TimeField are used.
Fields which handle relationships
Two fields are available for representing relationships between
models: ModelChoiceField and
ModelMultipleChoiceField. Both of these fields require a
single queryset parameter that is used to create the choices for
the field. Upon form validation, these fields will place either one
model object (in the case of ModelChoiceField) or multiple model
objects (in the case of ModelMultipleChoiceField) into the
cleaned_data dictionary of the form.
For more complex uses, you can specify queryset=None when declaring the
form field and then populate the queryset in the form’s __init__()
method:
class FooMultipleChoiceForm(forms.Form):
foo_select = forms.ModelMultipleChoiceField(queryset=None)
def __init__(self, *args, **kwargs):
super().__init__(*args, **kwargs)
self.fields["foo_select"].queryset = ...
Both ModelChoiceField and ModelMultipleChoiceField have an iterator
attribute which specifies the class used to iterate over the queryset when
generating choices. See Iterating relationship choices for details.
ModelChoiceField
class ModelChoiceField(**kwargs)[source]
Default widget: Select
Empty value: None
Normalizes to: A model instance.
Validates that the given id exists in the queryset.
Error message keys: required, invalid_choice
The invalid_choice error message may contain %(value)s, which will
be replaced with the selected choice.
Allows the selection of a single model object, suitable for representing a
foreign key. Note that the default widget for ModelChoiceField becomes
impractical when the number of entries increases. You should avoid using it
for more than 100 items.
A single argument is required:
queryset
A QuerySet of model objects from which the choices for the field
are derived and which is used to validate the user’s selection. It’s
evaluated when the form is rendered.
ModelChoiceField also takes several optional arguments:
empty_label
By default the <select> widget used by ModelChoiceField will have an
empty choice at the top of the list. You can change the text of this
label (which is "---------" by default) with the empty_label
attribute, or you can disable the empty label entirely by setting
empty_label to None:
# A custom empty label
field1 = forms.ModelChoiceField(queryset=..., empty_label="(Nothing)")
# No empty label
field2 = forms.ModelChoiceField(queryset=..., empty_label=None)
Note that no empty choice is created (regardless of the value of
empty_label) if a ModelChoiceField is required and has a
default initial value, or a widget is set to
RadioSelect and the
blank argument is False.
to_field_name
This optional argument is used to specify the field to use as the value
of the choices in the field’s widget. Be sure it’s a unique field for
the model, otherwise the selected value could match more than one
object. By default it is set to None, in which case the primary key
of each object will be used. For example:
# No custom to_field_name
field1 = forms.ModelChoiceField(queryset=...)
would yield:
<select id="id_field1" name="field1">
<option value="obj1.pk">Object1</option>
<option value="obj2.pk">Object2</option>
</select>
# to_field_name provided
field2 = forms.ModelChoiceField(queryset=..., to_field_name="name")
would yield:
<select id="id_field2" name="field2">
<option value="obj1.name">Object1</option>
<option value="obj2.name">Object2</option>
</select>
blank
When using the RadioSelect widget, this optional
boolean argument determines whether an empty choice is created. By
default, blank is False, in which case no empty choice is
created.
ModelChoiceField also has the attribute:
iterator
The iterator class used to generate field choices from queryset. By
default, ModelChoiceIterator.
The __str__() method of the model will be called to generate string
representations of the objects for use in the field’s choices. To provide
customized representations, subclass ModelChoiceField and override
label_from_instance. This method will receive a model object and should
return a string suitable for representing it. For example:
from django.forms import ModelChoiceField
class MyModelChoiceField(ModelChoiceField):
def label_from_instance(self, obj):
return "My Object #%i" % obj.id
Default widget: SelectMultiple
Empty value: An empty QuerySet (self.queryset.none())
Normalizes to: A QuerySet of model instances.
Validates that every id in the given list of values exists in the
queryset.
Error message keys: required, invalid_list, invalid_choice,
invalid_pk_value
The invalid_choice message may contain %(value)s and the
invalid_pk_value message may contain %(pk)s, which will be
substituted by the appropriate values.
Allows the selection of one or more model objects, suitable for
representing a many-to-many relation. As with ModelChoiceField,
you can use label_from_instance to customize the object
representations.
A single argument is required:
queryset
Same as ModelChoiceField.queryset.
Takes one optional argument:
to_field_name
Same as ModelChoiceField.to_field_name.
ModelMultipleChoiceField also has the attribute:
iterator
Same as ModelChoiceField.iterator.
Iterating relationship choices
By default, ModelChoiceField and ModelMultipleChoiceField use
ModelChoiceIterator to generate their field choices.
When iterated, ModelChoiceIterator yields 2-tuple choices containing
ModelChoiceIteratorValue instances as the first value element in
each choice. ModelChoiceIteratorValue wraps the choice value while
maintaining a reference to the source model instance that can be used in custom
widget implementations, for example, to add data-* attributes to
<option> elements.
For example, consider the following models:
from django.db import models
class Topping(models.Model):
name = models.CharField(max_length=100)
price = models.DecimalField(decimal_places=2, max_digits=6)
def __str__(self):
return self.name
class Pizza(models.Model):
topping = models.ForeignKey(Topping, on_delete=models.CASCADE)
You can use a Select widget subclass to include
the value of Topping.price as the HTML attribute data-price for each
<option> element:
from django import forms
class ToppingSelect(forms.Select):
def create_option(
self, name, value, label, selected, index, subindex=None, attrs=None
option = super().create_option(
name, value, label, selected, index, subindex, attrs
if value:
option["attrs"]["data-price"] = value.instance.price
return option
class PizzaForm(forms.ModelForm):
class Meta:
model = Pizza
fields = ["topping"]
widgets = {"topping": ToppingSelect}
This will render the Pizza.topping select as:
<select id="id_topping" name="topping" required>
<option value="" selected>---------</option>
<option value="1" data-price="1.50">mushrooms</option>
<option value="2" data-price="1.25">onions</option>
<option value="3" data-price="1.75">peppers</option>
<option value="4" data-price="2.00">pineapple</option>
</select>
For more advanced usage you may subclass ModelChoiceIterator in order to
customize the yielded 2-tuple choices.
ModelChoiceIterator
class ModelChoiceIterator(field)[source]
The default class assigned to the iterator attribute of
ModelChoiceField and ModelMultipleChoiceField. An
iterable that yields 2-tuple choices from the queryset.
A single argument is required:
field
The instance of ModelChoiceField or ModelMultipleChoiceField to
iterate and yield choices.
ModelChoiceIterator has the following method:
__iter__()[source]
Yields 2-tuple choices, in the (value, label) format used by
ChoiceField.choices. The first value element is a
ModelChoiceIteratorValue instance.
class ModelChoiceIteratorValue(value, instance)[source]
Two arguments are required:
value
The value of the choice. This value is used to render the value
attribute of an HTML <option> element.
instance
The model instance from the queryset. The instance can be accessed in
custom ChoiceWidget.create_option() implementations to adjust the
rendered HTML.
ModelChoiceIteratorValue has the following method:
__str__()[source]
Return value as a string to be rendered in HTML.
Creating custom fields
If the built-in Field classes don’t meet your needs, you can create custom
Field classes. To do this, create a subclass of django.forms.Field. Its
only requirements are that it implement a clean() method and that its
__init__() method accept the core arguments mentioned above (required,
label, initial, widget, help_text).
You can also customize how a field will be accessed by overriding
get_bound_field().
Try the FAQ — it's got answers to many common questions.
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