When you create a Form class, the most important part is defining the\nfields of the form. Each field has custom validation logic, along with a few\nother hooks.
Although the primary way you’ll use Field classes is in Form classes,\nyou can also instantiate them and use them directly to get a better idea of\nhow they work. Each Field instance has a clean() method, which takes\na single argument and either raises a\ndjango.core.exceptions.ValidationError exception or returns the clean\nvalue:
>>> from django import forms\n>>> f = forms.EmailField()\n>>> f.clean("foo@example.com")\n'foo@example.com'\n>>> f.clean("invalid email address")\nTraceback (most recent call last):\n...\nValidationError: ['Enter a valid email address.']\nEach Field class constructor takes at least these arguments. Some\nField classes take additional, field-specific arguments, but the following\nshould always be accepted:
requiredLink to this heading#By default, each Field class assumes the value is required, so if you pass\nan empty value – either None or the empty string ("") – then\nclean() will raise a ValidationError exception:
>>> from django import forms\n>>> f = forms.CharField()\n>>> f.clean("foo")\n'foo'\n>>> f.clean("")\nTraceback (most recent call last):\n...\nValidationError: ['This field is required.']\n>>> f.clean(None)\nTraceback (most recent call last):\n...\nValidationError: ['This field is required.']\n>>> f.clean(0)\n'0'\n>>> f.clean(True)\n'True'\n>>> f.clean(False)\n'False'\nTo specify that a field is not required, pass required=False to the\nField constructor:
>>> f = forms.CharField(required=False)\n>>> f.clean("foo")\n'foo'\n>>> f.clean("")\n''\n>>> f.clean(None)\n''\n>>> f.clean(0)\n'0'\n>>> f.clean(True)\n'True'\n>>> f.clean(False)\n'False'\nIf a Field has required=False and you pass clean() an empty value,\nthen clean() will return a normalized empty value rather than raising\nValidationError. For CharField, this will return\nempty_value which defaults to an empty string. For other\nField classes, it might be None. (This varies from field to field.)
Widgets of required form fields have the required HTML attribute. Set the\nForm.use_required_attribute attribute to False to disable it. The\nrequired attribute isn’t included on forms of formsets because the browser\nvalidation may not be correct when adding and deleting formsets.
labelLink to this heading#The label argument lets you specify the “human-friendly” label for this\nfield. This is used when the Field is displayed in a Form.
As explained in Outputting forms as HTML, the default label for a\nField is generated from the field name by converting all underscores to\nspaces and upper-casing the first letter. Specify label if that default\nbehavior doesn’t result in an adequate label.
Here’s a full example Form that implements label for two of its fields.\nWe’ve specified auto_id=False to simplify the output:
>>> from django import forms\n>>> class CommentForm(forms.Form):\n... name = forms.CharField(label="Your name")\n... url = forms.URLField(label="Your website", required=False)\n... comment = forms.CharField()\n...\n>>> f = CommentForm(auto_id=False)\n>>> print(f)\n<div>Your name:<input type="text" name="name" required></div>\n<div>Your website:<input type="url" name="url"></div>\n<div>Comment:<input type="text" name="comment" required></div>\nlabel_suffixLink to this heading#The label_suffix argument lets you override the form’s\nlabel_suffix on a per-field basis:
>>> class ContactForm(forms.Form):\n... age = forms.IntegerField()\n... nationality = forms.CharField()\n... captcha_answer = forms.IntegerField(label="2 + 2", label_suffix=" =")\n...\n>>> f = ContactForm(label_suffix="?")\n>>> print(f)\n<div><label for="id_age">Age?</label><input type="number" name="age" required id="id_age"></div>\n<div><label for="id_nationality">Nationality?</label><input type="text" name="nationality" required id="id_nationality"></div>\n<div><label for="id_captcha_answer">2 + 2 =</label><input type="number" name="captcha_answer" required id="id_captcha_answer"></div>\ninitialLink to this heading#The initial argument lets you specify the initial value to use when\nrendering 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\nfield is initialized to a particular value. For example:
\n>>> from django import forms\n>>> class CommentForm(forms.Form):\n... name = forms.CharField(initial="Your name")\n... url = forms.URLField(initial="https://")\n... comment = forms.CharField()\n...\n>>> f = CommentForm(auto_id=False)\n>>> print(f)\n<div>Name:<input type="text" name="name" value="Your name" required></div>\n<div>Url:<input type="url" name="url" value="https://" required></div>\n<div>Comment:<input type="text" name="comment" required></div>\nYou may be thinking, why not just pass a dictionary of the initial values as\ndata when displaying the form? Well, if you do that, you’ll trigger validation,\nand the HTML output will include any validation errors:
\n>>> class CommentForm(forms.Form):\n... name = forms.CharField()\n... url = forms.URLField()\n... comment = forms.CharField()\n...\n>>> default_data = {"name": "Your name", "url": "https://"}\n>>> f = CommentForm(default_data, auto_id=False)\n>>> print(f)\n<div>Name:\n <input type="text" name="name" value="Your name" required>\n</div>\n<div>Url:\n <ul class="errorlist"><li>Enter a valid URL.</li></ul>\n <input type="url" name="url" value="https://" required aria-invalid="true">\n</div>\n<div>Comment:\n <ul class="errorlist"><li>This field is required.</li></ul>\n <input type="text" name="comment" required aria-invalid="true">\n</div>\nThis is why initial values are only displayed for unbound forms. For bound\nforms, the HTML output will use the bound data.
Also note that initial values are not used as “fallback” data in\nvalidation if a particular field’s value is not given. initial values are\nonly intended for initial form display:
>>> class CommentForm(forms.Form):\n... name = forms.CharField(initial="Your name")\n... url = forms.URLField(initial="https://")\n... comment = forms.CharField()\n...\n>>> data = {"name": "", "url": "", "comment": "Foo"}\n>>> f = CommentForm(data)\n>>> f.is_valid()\nFalse\n# The form does *not* fallback to using the initial values.\n>>> f.errors\n{'url': ['This field is required.'], 'name': ['This field is required.']}\nInstead of a constant, you can also pass any callable:
\n>>> import datetime\n>>> class DateForm(forms.Form):\n... day = forms.DateField(initial=datetime.date.today)\n...\n>>> print(DateForm())\n<div><label for="id_day">Day:</label><input type="text" name="day" value="2023-02-11" required id="id_day"></div>\nThe callable will be evaluated only when the unbound form is displayed, not when it is defined.
\nwidgetLink to this heading#The widget argument lets you specify a Widget class to use when\nrendering this Field. See Widgets for more information.
help_textLink to this heading#The help_text argument lets you specify descriptive text for this\nField. If you provide help_text, it will be displayed next to the\nField when the Field is rendered by one of the convenience Form\nmethods (e.g., as_ul()).
Like the model field’s help_text, this value\nisn’t HTML-escaped in automatically-generated forms.
Here’s a full example Form that implements help_text for two of its\nfields. We’ve specified auto_id=False to simplify the output:
>>> from django import forms\n>>> class HelpTextContactForm(forms.Form):\n... subject = forms.CharField(max_length=100, help_text="100 characters max.")\n... message = forms.CharField()\n... sender = forms.EmailField(help_text="A valid email address, please.")\n... cc_myself = forms.BooleanField(required=False)\n...\n>>> f = HelpTextContactForm(auto_id=False)\n>>> print(f)\n<div>Subject:<div class="helptext">100 characters max.</div><input type="text" name="subject" maxlength="100" required></div>\n<div>Message:<input type="text" name="message" required></div>\n<div>Sender:<div class="helptext">A valid email address, please.</div><input type="email" name="sender" required></div>\n<div>Cc myself:<input type="checkbox" name="cc_myself"></div>\nWhen a field has help text it is associated with its input using the\naria-describedby HTML attribute. If the widget is rendered in a\n<fieldset> then aria-describedby is added to this element, otherwise it\nis added to the widget’s <input>:
>>> from django import forms\n>>> class UserForm(forms.Form):\n... username = forms.CharField(max_length=255, help_text="e.g., user@example.com")\n...\n>>> f = UserForm()\n>>> print(f)\n<div>\n<label for="id_username">Username:</label>\n<div class="helptext" id="id_username_helptext">e.g., user@example.com</div>\n<input type="text" name="username" maxlength="255" required aria-describedby="id_username_helptext" id="id_username">\n</div>\nWhen adding a custom aria-describedby attribute, make sure to also include\nthe id of the help_text element (if used) in the desired order. For\nscreen reader users, descriptions will be read in their order of appearance\ninside aria-describedby:
>>> class UserForm(forms.Form):\n... username = forms.CharField(\n... max_length=255,\n... help_text="e.g., user@example.com",\n... widget=forms.TextInput(\n... attrs={"aria-describedby": "custom-description id_username_helptext"},\n... ),\n... )\n...\n>>> f = UserForm()\n>>> print(f["username"])\n<input type="text" name="username" aria-describedby="custom-description id_username_helptext" maxlength="255" id="id_username" required>\nerror_messagesLink to this heading#The error_messages argument lets you override the default messages that the\nfield will raise. Pass in a dictionary with keys matching the error messages you\nwant to override. For example, here is the default error message:
>>> from django import forms\n>>> generic = forms.CharField()\n>>> generic.clean("")\nTraceback (most recent call last):\n ...\nValidationError: ['This field is required.']\nAnd here is a custom error message:
\n>>> name = forms.CharField(error_messages={"required": "Please enter your name"})\n>>> name.clean("")\nTraceback (most recent call last):\n ...\nValidationError: ['Please enter your name']\nIn the built-in Field classes section below, each Field defines the\nerror message keys it uses.
validatorsLink to this heading#The validators argument lets you provide a list of validation functions\nfor this field.
See the validators documentation for more information.
\nlocalizeLink to this heading#The localize argument enables the localization of form data input, as well\nas the rendered output.
See the format localization documentation for\nmore information.
\ndisabledLink to this heading#The disabled boolean argument, when set to True, disables a form field\nusing the disabled HTML attribute so that it won’t be editable by users.\nEven if a user tampers with the field’s value submitted to the server, it will\nbe ignored in favor of the value from the form’s initial data.
template_nameLink to this heading#The template_name argument allows a custom template to be used when the\nfield is rendered with as_field_group(). By\ndefault this value is set to "django/forms/field.html". Can be changed per\nfield by overriding this attribute or more generally by overriding the default\ntemplate, see also Overriding built-in field templates.
has_changed()Link to this heading#The has_changed() method is used to determine if the field value has changed\nfrom the initial value. Returns True or False.
See the Form.has_changed() documentation for more information.
Field classesLink to this heading#Naturally, the forms library comes with a set of Field classes that\nrepresent common validation needs. This section documents each built-in field.
For each field, we describe the default widget used if you don’t specify\nwidget. We also specify the value returned when you provide an empty value\n(see the section on required above to understand what that means).
BooleanFieldLink to this heading#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\nthe field has required=True.
Error message keys: required
CharFieldLink to this heading#Default widget: TextInput
Empty value: Whatever you’ve given as empty_value.
Normalizes to: A string.
Uses MaxLengthValidator and\nMinLengthValidator if max_length and\nmin_length are provided. Otherwise, all inputs are valid.
Error message keys: required, max_length, min_length
Has the following optional arguments for validation:
\nIf provided, these arguments ensure that the string is at most or at\nleast the given length.
\nIf True (default), the value will be stripped of leading and\ntrailing whitespace.
The value to use to represent “empty”. Defaults to an empty string.
\nChoiceFieldLink to this heading#Default widget: Select
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\nreplaced with the selected choice.
Takes one extra argument:
\nEither an iterable of 2-tuples to use as choices for this\nfield, enumeration type, or a\ncallable that returns such an iterable. This argument accepts the same\nformats as the choices argument to a model field. See the\nmodel field reference documentation on choices\nfor more details. If the argument is a callable, it is evaluated each\ntime the field’s form is initialized, in addition to during rendering.\nDefaults to an empty list.
DateFieldLink to this heading#Default widget: DateInput
Empty value: None
Normalizes to: A Python datetime.date object.
Validates that the given value is either a datetime.date,\ndatetime.datetime or string formatted in a particular date format.
Error message keys: required, invalid
Takes one optional argument:
\nAn iterable of formats used to attempt to convert a string to a valid\ndatetime.date object.
If no input_formats argument is provided, the default input formats are\ntaken from the active locale format DATE_INPUT_FORMATS key, or from\nDATE_INPUT_FORMATS if localization is disabled. See also\nformat localization.
DateTimeFieldLink to this heading#Default widget: DateTimeInput
Empty value: None
Normalizes to: A Python datetime.datetime object.
Validates that the given value is either a datetime.datetime,\ndatetime.date or string formatted in a particular datetime format.
Error message keys: required, invalid
Takes one optional argument:
\nAn iterable of formats used to attempt to convert a string to a valid\ndatetime.datetime object, in addition to ISO 8601 formats.
The field always accepts strings in ISO 8601 formatted dates or similar\nrecognized by parse_datetime(). Some examples\nare:
'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\ntaken from the active locale format DATETIME_INPUT_FORMATS and\nDATE_INPUT_FORMATS keys, or from DATETIME_INPUT_FORMATS and\nDATE_INPUT_FORMATS if localization is disabled. See also\nformat localization.
DecimalFieldLink to this heading#Default widget: NumberInput when Field.localize is\nFalse, else TextInput.
Empty value: None
Normalizes to: A Python decimal.
Validates that the given value is a decimal. Uses\nMaxValueValidator and\nMinValueValidator if max_value and\nmin_value are provided. Uses\nStepValueValidator if step_size is\nprovided. Leading and trailing whitespace is ignored.
Error message keys: required, invalid, max_value,\nmin_value, max_digits, max_decimal_places,\nmax_whole_digits, step_size.
The max_value and min_value error messages may contain\n%(limit_value)s, which will be substituted by the appropriate limit.\nSimilarly, the max_digits, max_decimal_places and\nmax_whole_digits error messages may contain %(max)s.
Takes five optional arguments:
\nThese control the range of values permitted in the field, and should be\ngiven as decimal.Decimal values.
The maximum number of digits (those before the decimal point plus those\nafter the decimal point, with leading zeros stripped) permitted in the\nvalue.
\nThe maximum number of decimal places permitted.
\nLimit valid inputs to an integral multiple of step_size. If\nmin_value is also provided, it’s added as an offset to determine if\nthe step size matches.
DurationFieldLink to this heading#Default widget: TextInput
Empty value: None
Normalizes to: A Python timedelta.
Validates that the given value is a string which can be converted into a\ntimedelta. The value must be between datetime.timedelta.min\nand datetime.timedelta.max.
Error message keys: required, invalid, overflow.
Accepts any format understood by\nparse_duration().
EmailFieldLink to this heading#Default widget: EmailInput
Empty value: Whatever you’ve given as empty_value.
Normalizes to: A string.
Uses EmailValidator to validate that\nthe given value is a valid email address, using a moderately complex\nregular expression.
Error message keys: required, invalid
Has the optional arguments max_length, min_length, and\nempty_value which work just as they do for CharField. The\nmax_length argument defaults to 320 (see RFC 3696 Section 3).
FileFieldLink to this heading#Default widget: ClearableFileInput
Empty value: None
Normalizes to: An UploadedFile object that wraps the file content\nand 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,\nmax_length
Has the optional arguments for validation: max_length and\nallow_empty_file. If provided, these ensure that the file name is at\nmost the given length, and that validation will succeed even if the file\ncontent is empty.
To learn more about the UploadedFile object, see the file uploads\ndocumentation.
When you use a FileField in a form, you must also remember to\nbind the file data to the form.
The max_length error refers to the length of the filename. In the error\nmessage for that key, %(max)d will be replaced with the maximum filename\nlength and %(length)d will be replaced with the current filename length.
FilePathFieldLink to this heading#Default widget: Select
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\nextra arguments; only path is required:
The absolute path to the directory whose contents you want listed. This\ndirectory must exist.
\nIf False (the default) only the direct contents of path will be\noffered as choices. If True, the directory will be descended into\nrecursively and all descendants will be listed as choices.
A regular expression pattern; only files with names matching this expression\nwill be allowed as choices.
\nOptional. Either True or False. Default is True. Specifies\nwhether files in the specified location should be included. Either this or\nallow_folders must be True.
Optional. Either True or False. Default is False. Specifies\nwhether folders in the specified location should be included. Either this or\nallow_files must be True.
FloatFieldLink to this heading#Default widget: NumberInput when Field.localize is\nFalse, else TextInput.
Empty value: None
Normalizes to: A Python float.
Validates that the given value is a float. Uses\nMaxValueValidator and\nMinValueValidator if max_value and\nmin_value are provided. Uses\nStepValueValidator if step_size is\nprovided. Leading and trailing whitespace is allowed, as in Python’s\nfloat() function.
Error message keys: required, invalid, max_value,\nmin_value, step_size.
Takes three optional arguments:
\nThese control the range of values permitted in the field.
\nLimit valid inputs to an integral multiple of step_size. If\nmin_value is also provided, it’s added as an offset to determine if\nthe step size matches.
GenericIPAddressFieldLink to this heading#A field containing either an IPv4 or an IPv6 address.
\nDefault 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, max_length
The IPv6 address normalization follows RFC 4291 Section 2.2 section 2.2,\nincluding using the IPv4 format suggested in paragraph 3 of that section, like\n::ffff:192.0.2.0. For example, 2001:0::0:01 would be normalized to\n2001::1, and ::ffff:0a0a:0a0a to ::ffff:10.10.10.10. All characters\nare converted to lowercase.
Takes three optional arguments:
\nLimits valid inputs to the specified protocol.\nAccepted values are both (default), IPv4\nor IPv6. Matching is case insensitive.
Unpacks IPv4 mapped addresses like ::ffff:192.0.2.1.\nIf this option is enabled that address would be unpacked to\n192.0.2.1. Default is disabled. Can only be used\nwhen protocol is set to 'both'.
Defaults to 39, and behaves the same way as it does for\nCharField.
ImageFieldLink to this heading#Default widget: ClearableFileInput
Empty value: None
Normalizes to: An UploadedFile object that wraps the file content\nand file name into a single object.
Validates that file data has been bound to the form. Also uses\nFileExtensionValidator to validate that\nthe file extension is supported by Pillow.
Error message keys: required, invalid, missing, empty,\ninvalid_image
Using an ImageField requires that pillow is installed with\nsupport for the image formats you use. If you encounter a corrupt image\nerror when you upload an image, it usually means that Pillow doesn’t\nunderstand its format. To fix this, install the appropriate library and\nreinstall Pillow.
When you use an ImageField on a form, you must also remember to\nbind the file data to the form.
After the field has been cleaned and validated, the UploadedFile\nobject will have an additional image attribute containing the Pillow\nImage instance used to check if the file was a valid image. Pillow\ncloses the underlying file descriptor after verifying an image, so while\nnon-image data attributes, such as format, height, and width,\nare available, methods that access the underlying image data, such as\ngetdata() or getpixel(), cannot be used without reopening the file.\nFor example:
>>> from PIL import Image\n>>> from django import forms\n>>> from django.core.files.uploadedfile import SimpleUploadedFile\n>>> class ImageForm(forms.Form):\n... img = forms.ImageField()\n...\n>>> file_data = {"img": SimpleUploadedFile("test.png", b"file data")}\n>>> form = ImageForm({}, file_data)\n# Pillow closes the underlying file descriptor.\n>>> form.is_valid()\nTrue\n>>> image_field = form.cleaned_data["img"]\n>>> image_field.image\n<PIL.PngImagePlugin.PngImageFile image mode=RGBA size=191x287 at 0x7F5985045C18>\n>>> image_field.image.width\n191\n>>> image_field.image.height\n287\n>>> image_field.image.format\n'PNG'\n>>> image_field.image.getdata()\n# Raises AttributeError: 'NoneType' object has no attribute 'seek'.\n>>> image = Image.open(image_field)\n>>> image.getdata()\n<ImagingCore object at 0x7f5984f874b0>\nAdditionally, UploadedFile.content_type will be updated with the\nimage’s content type if Pillow can determine it, otherwise it will be set\nto None.
IntegerFieldLink to this heading#Default widget: NumberInput when Field.localize is\nFalse, else TextInput.
Empty value: None
Normalizes to: A Python integer.
Validates that the given value is an integer. Uses\nMaxValueValidator and\nMinValueValidator if max_value and\nmin_value are provided. Uses\nStepValueValidator if step_size is\nprovided. Leading and trailing whitespace is allowed, as in Python’s\nint() function.
Error message keys: required, invalid, max_value,\nmin_value, step_size
The max_value, min_value and step_size error messages may\ncontain %(limit_value)s, which will be substituted by the appropriate\nlimit.
Takes three optional arguments for validation:
\nThese control the range of values permitted in the field.
\nLimit valid inputs to an integral multiple of step_size. If\nmin_value is also provided, it’s added as an offset to determine if\nthe step size matches.
JSONFieldLink to this heading#A field which accepts JSON encoded data for a\nJSONField.
Default widget: Textarea
Empty value: None
Normalizes to: A Python representation of the JSON value (usually as a\ndict, 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:
\nA json.JSONEncoder subclass to serialize data types not\nsupported by the standard JSON serializer (e.g. datetime.datetime\nor UUID). For example, you can use the\nDjangoJSONEncoder class.
Defaults to json.JSONEncoder.
A json.JSONDecoder subclass to deserialize the input. Your\ndeserialization may need to account for the fact that you can’t be\ncertain of the input type. For example, you run the risk of returning a\ndatetime that was actually a string that just happened to be in the\nsame format chosen for datetimes.
The decoder can be used to validate the input. If\njson.JSONDecodeError is raised during the deserialization,\na ValidationError will be raised.
Defaults to json.JSONDecoder.
MultipleChoiceFieldLink to this heading#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\nof choices.
Error message keys: required, invalid_choice, invalid_list
The invalid_choice error message may contain %(value)s, which will be\nreplaced with the selected choice.
Takes one extra required argument, choices, as for ChoiceField.
NullBooleanFieldLink to this heading#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\nSelect or RadioSelect\nby providing the widget choices:
NullBooleanField(\n widget=Select(\n choices=[\n ("", "Unknown"),\n (True, "Yes"),\n (False, "No"),\n ]\n )\n)\nRegexFieldLink to this heading#Default widget: TextInput
Empty value: Whatever you’ve given as empty_value.
Normalizes to: A string.
Uses RegexValidator to validate that\nthe given value matches a certain regular expression.
Error message keys: required, invalid
Takes one required argument:
\nA regular expression specified either as a string or a compiled regular\nexpression object.
\nAlso takes max_length, min_length, strip, and empty_value\nwhich work just as they do for CharField.
Defaults to False. If enabled, stripping will be applied before the\nregex validation.
SlugFieldLink to this heading#Default widget: TextInput
Empty value: Whatever you’ve given as empty_value.
Normalizes to: A string.
Uses validate_slug or\nvalidate_unicode_slug to validate that\nthe given value contains only letters, numbers, underscores, and hyphens.
Error messages: required, invalid
This field is intended for use in representing a model\nSlugField in forms.
Takes two optional parameters:
\nA boolean instructing the field to accept Unicode letters in addition\nto ASCII letters. Defaults to False.
The value to use to represent “empty”. Defaults to an empty string.
\nTimeFieldLink to this heading#Default widget: TimeInput
Empty value: None
Normalizes to: A Python datetime.time object.
Validates that the given value is either a datetime.time or string\nformatted in a particular time format.
Error message keys: required, invalid
Takes one optional argument:
\nAn iterable of formats used to attempt to convert a string to a valid\ndatetime.time object.
If no input_formats argument is provided, the default input formats are\ntaken from the active locale format TIME_INPUT_FORMATS key, or from\nTIME_INPUT_FORMATS if localization is disabled. See also\nformat localization.
TypedChoiceFieldLink to this heading#Just like a ChoiceField, except TypedChoiceField takes two\nextra 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\nargument.
Validates that the given value exists in the list of choices and can be\ncoerced.
Error message keys: required, invalid_choice
Takes extra arguments:
\nA function that takes one argument and returns a coerced value. Examples\ninclude the built-in int, float, bool and other types. Defaults\nto an identity function. Note that coercion happens after input\nvalidation, so it is possible to coerce to a value not present in\nchoices.
The value to use to represent “empty.” Defaults to the empty string;\nNone is another common choice here. Note that this value will not be\ncoerced by the function given in the coerce argument, so choose it\naccordingly.
TypedMultipleChoiceFieldLink to this heading#Just like a MultipleChoiceField, except TypedMultipleChoiceField\ntakes 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\nargument.
Validates that the given values exists in the list of choices and can be\ncoerced.
Error message keys: required, invalid_choice
The invalid_choice error message may contain %(value)s, which will be\nreplaced with the selected choice.
Takes two extra arguments, coerce and empty_value, as for\nTypedChoiceField.
URLFieldLink to this heading#Default widget: URLInput
Empty value: Whatever you’ve given as empty_value.
Normalizes to: A string.
Uses URLValidator to validate that the\ngiven value is a valid URL.
Error message keys: required, invalid
Has the optional arguments max_length, min_length, empty_value\nwhich work just as they do for CharField, and one more argument:
The scheme assumed for URLs provided without one. Defaults to\n"http". For example, if assume_scheme is "https" and the\nprovided value is "example.com", the normalized value will be\n"https://example.com".
UUIDFieldLink to this heading#Default widget: TextInput
Empty value: None
Normalizes to: A UUID object.
Error message keys: required, invalid
This field will accept any string format accepted as the hex argument\nto the UUID constructor.
Field classesLink to this heading#ComboFieldLink to this heading#Default widget: TextInput
Empty value: '' (an empty string)
Normalizes to: A string.
Validates the given value against each of the fields specified\nas an argument to the ComboField.
Error message keys: required, invalid
Takes one extra required argument:
\nThe list of fields that should be used to validate the field’s value (in\nthe order in which they are provided).
\n>>> from django.forms import ComboField\n>>> f = ComboField(fields=[CharField(max_length=20), EmailField()])\n>>> f.clean("test@example.com")\n'test@example.com'\n>>> f.clean("longemailaddress@example.com")\nTraceback (most recent call last):\n...\nValidationError: ['Ensure this value has at most 20 characters (it has 28).']\nMultiValueFieldLink to this heading#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\nas an argument to the MultiValueField.
Error message keys: required, invalid, incomplete
Aggregates the logic of multiple fields that together produce a single\nvalue.
\nThis field is abstract and must be subclassed. In contrast with the\nsingle-value fields, subclasses of MultiValueField must not\nimplement clean() but instead - implement\ncompress().
Takes one extra required argument:
\nA tuple of fields whose values are cleaned and subsequently combined\ninto a single value. Each value of the field is cleaned by the\ncorresponding field in fields – the first value is cleaned by the\nfirst field, the second value is cleaned by the second field, etc.\nOnce all fields are cleaned, the list of clean values is combined into\na single value by compress().
Also takes some optional arguments:
\nDefaults to True, in which case a required validation error\nwill be raised if no value is supplied for any field.
When set to False, the Field.required attribute can be set\nto False for individual fields to make them optional. If no value\nis supplied for a required field, an incomplete validation error\nwill be raised.
A default incomplete error message can be defined on the\nMultiValueField subclass, or different messages can be defined\non each individual field. For example:
from django.core.validators import RegexValidator\n\n\nclass PhoneField(MultiValueField):\n def __init__(self, **kwargs):\n # Define one message for all fields.\n error_messages = {\n "incomplete": "Enter a country calling code and a phone number.",\n }\n # Or define a different message for each field.\n fields = (\n CharField(\n error_messages={"incomplete": "Enter a country calling code."},\n validators=[\n RegexValidator(r"^[0-9]+$", "Enter a valid country calling code."),\n ],\n ),\n CharField(\n error_messages={"incomplete": "Enter a phone number."},\n validators=[RegexValidator(r"^[0-9]+$", "Enter a valid phone number.")],\n ),\n CharField(\n validators=[RegexValidator(r"^[0-9]+$", "Enter a valid extension.")],\n required=False,\n ),\n )\n super().__init__(\n error_messages=error_messages,\n fields=fields,\n require_all_fields=False,\n **kwargs\n )\nMust be a subclass of django.forms.MultiWidget.\nDefault value is TextInput, which\nprobably is not very useful in this case.
Takes a list of valid values and returns a “compressed” version of\nthose values – in a single value. For example,\nSplitDateTimeField is a subclass which combines a time field\nand a date field into a datetime object.
This method must be implemented in the subclasses.
\nSplitDateTimeFieldLink to this heading#Default widget: SplitDateTimeWidget
Empty value: None
Normalizes to: A Python datetime.datetime object.
Validates that the given value is a datetime.datetime or string\nformatted in a particular datetime format.
Error message keys: required, invalid, invalid_date,\ninvalid_time
Takes two optional arguments:
\nA list of formats used to attempt to convert a string to a valid\ndatetime.date object.
If no input_date_formats argument is provided, the default input formats\nfor DateField are used.
A list of formats used to attempt to convert a string to a valid\ndatetime.time object.
If no input_time_formats argument is provided, the default input formats\nfor TimeField are used.
Two fields are available for representing relationships between\nmodels: ModelChoiceField and\nModelMultipleChoiceField. Both of these fields require a\nsingle queryset parameter that is used to create the choices for\nthe field. Upon form validation, these fields will place either one\nmodel object (in the case of ModelChoiceField) or multiple model\nobjects (in the case of ModelMultipleChoiceField) into the\ncleaned_data dictionary of the form.
For more complex uses, you can specify queryset=None when declaring the\nform field and then populate the queryset in the form’s __init__()\nmethod:
class FooMultipleChoiceForm(forms.Form):\n foo_select = forms.ModelMultipleChoiceField(queryset=None)\n\n def __init__(self, *args, **kwargs):\n super().__init__(*args, **kwargs)\n self.fields["foo_select"].queryset = ...\nBoth ModelChoiceField and ModelMultipleChoiceField have an iterator\nattribute which specifies the class used to iterate over the queryset when\ngenerating choices. See Iterating relationship choices for details.
ModelChoiceFieldLink to this heading#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\nbe replaced with the selected choice.
Allows the selection of a single model object, suitable for representing a\nforeign key. Note that the default widget for ModelChoiceField becomes\nimpractical when the number of entries increases. You should avoid using it\nfor more than 100 items.
A single argument is required:
\nA QuerySet of model objects from which the choices for the field\nare derived and which is used to validate the user’s selection. It’s\nevaluated when the form is rendered.
ModelChoiceField also takes several optional arguments:
By default the <select> widget used by ModelChoiceField will have an\nempty choice at the top of the list. You can change the text of this\nlabel (which is "---------" by default) with the empty_label\nattribute, or you can disable the empty label entirely by setting\nempty_label to None:
# A custom empty label\nfield1 = forms.ModelChoiceField(queryset=..., empty_label="(Nothing)")\n\n# No empty label\nfield2 = forms.ModelChoiceField(queryset=..., empty_label=None)\nNote that no empty choice is created (regardless of the value of\nempty_label) if a ModelChoiceField is required and has a\ndefault initial value, or a widget is set to\nRadioSelect and the\nblank argument is False.
This optional argument is used to specify the field to use as the value\nof the choices in the field’s widget. Be sure it’s a unique field for\nthe model, otherwise the selected value could match more than one\nobject. By default it is set to None, in which case the primary key\nof each object will be used. For example:
# No custom to_field_name\nfield1 = forms.ModelChoiceField(queryset=...)\nwould yield:
\n<select id="id_field1" name="field1">\n<option value="obj1.pk">Object1</option>\n<option value="obj2.pk">Object2</option>\n...\n</select>\nand:
\n# to_field_name provided\nfield2 = forms.ModelChoiceField(queryset=..., to_field_name="name")\nwould yield:
\n<select id="id_field2" name="field2">\n<option value="obj1.name">Object1</option>\n<option value="obj2.name">Object2</option>\n...\n</select>\nWhen using the RadioSelect widget, this optional\nboolean argument determines whether an empty choice is created. By\ndefault, blank is False, in which case no empty choice is\ncreated.
ModelChoiceField also has the attribute:
The iterator class used to generate field choices from queryset. By\ndefault, ModelChoiceIterator.
The __str__() method of the model will be called to generate string\nrepresentations of the objects for use in the field’s choices. To provide\ncustomized representations, subclass ModelChoiceField and override\nlabel_from_instance. This method will receive a model object and should\nreturn a string suitable for representing it. For example:
from django.forms import ModelChoiceField\n\n\nclass MyModelChoiceField(ModelChoiceField):\n def label_from_instance(self, obj):\n return "My Object #%i" % obj.id\nModelMultipleChoiceFieldLink to this heading#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\nqueryset.
Error message keys: required, invalid_list, invalid_choice,\ninvalid_pk_value
The invalid_choice message may contain %(value)s and the\ninvalid_pk_value message may contain %(pk)s, which will be\nsubstituted by the appropriate values.
Allows the selection of one or more model objects, suitable for\nrepresenting a many-to-many relation. As with ModelChoiceField,\nyou can use label_from_instance to customize the object\nrepresentations.
A single argument is required:
\nSame as ModelChoiceField.queryset.
Takes one optional argument:
\nSame as ModelChoiceField.to_field_name.
ModelMultipleChoiceField also has the attribute:
Same as ModelChoiceField.iterator.
By default, ModelChoiceField and ModelMultipleChoiceField use\nModelChoiceIterator to generate their field choices.
When iterated, ModelChoiceIterator yields 2-tuple choices containing\nModelChoiceIteratorValue instances as the first value element in\neach choice. ModelChoiceIteratorValue wraps the choice value while\nmaintaining a reference to the source model instance that can be used in custom\nwidget implementations, for example, to add data-* attributes to\n<option> elements.
For example, consider the following models:
\nfrom django.db import models\n\n\nclass Topping(models.Model):\n name = models.CharField(max_length=100)\n price = models.DecimalField(decimal_places=2, max_digits=6)\n\n def __str__(self):\n return self.name\n\n\nclass Pizza(models.Model):\n topping = models.ForeignKey(Topping, on_delete=models.CASCADE)\nYou can use a Select widget subclass to include\nthe value of Topping.price as the HTML attribute data-price for each\n<option> element:
from django import forms\n\n\nclass ToppingSelect(forms.Select):\n def create_option(\n self, name, value, label, selected, index, subindex=None, attrs=None\n ):\n option = super().create_option(\n name, value, label, selected, index, subindex, attrs\n )\n if value:\n option["attrs"]["data-price"] = value.instance.price\n return option\n\n\nclass PizzaForm(forms.ModelForm):\n class Meta:\n model = Pizza\n fields = ["topping"]\n widgets = {"topping": ToppingSelect}\nThis will render the Pizza.topping select as:
<select id="id_topping" name="topping" required>\n<option value="" selected>---------</option>\n<option value="1" data-price="1.50">mushrooms</option>\n<option value="2" data-price="1.25">onions</option>\n<option value="3" data-price="1.75">peppers</option>\n<option value="4" data-price="2.00">pineapple</option>\n</select>\nFor more advanced usage you may subclass ModelChoiceIterator in order to\ncustomize the yielded 2-tuple choices.
ModelChoiceIteratorLink to this heading#The default class assigned to the iterator attribute of\nModelChoiceField and ModelMultipleChoiceField. An\niterable that yields 2-tuple choices from the queryset.
A single argument is required:
\nThe instance of ModelChoiceField or ModelMultipleChoiceField to\niterate and yield choices.
ModelChoiceIterator has the following method:
Yields 2-tuple choices, in the (value, label) format used by\nChoiceField.choices. The first value element is a\nModelChoiceIteratorValue instance.
ModelChoiceIteratorValueLink to this heading#Two arguments are required:
\nThe value of the choice. This value is used to render the value\nattribute of an HTML <option> element.
The model instance from the queryset. The instance can be accessed in\ncustom ChoiceWidget.create_option() implementations to adjust the\nrendered HTML.
ModelChoiceIteratorValue has the following method:
Return value as a string to be rendered in HTML.
If the built-in Field classes don’t meet your needs, you can create custom\nField classes. To do this, create a subclass of django.forms.Field. Its\nonly requirements are that it implement a clean() method and that its\n__init__() method accept the core arguments mentioned above (required,\nlabel, initial, widget, help_text).
You can also customize how a field will be accessed by overriding\nget_bound_field().