mirror of
https://github.com/django/django.git
synced 2025-09-17 22:49:35 +00:00
f81e6e3a53
Lines in the docs files were manually adjusted to conform to the 79 columns limit per line (plus newline), improving readability and consistency across the content.
394 lines
14 KiB
Plaintext
394 lines
14 KiB
Plaintext
==========
|
|
Validators
|
|
==========
|
|
|
|
.. module:: django.core.validators
|
|
:synopsis: Validation utilities and base classes
|
|
|
|
Writing validators
|
|
==================
|
|
|
|
A validator is a callable that takes a value and raises a
|
|
:exc:`~django.core.exceptions.ValidationError` if it doesn't meet some
|
|
criteria. Validators can be useful for reusing validation logic between
|
|
different types of fields.
|
|
|
|
For example, here's a validator that only allows even numbers::
|
|
|
|
from django.core.exceptions import ValidationError
|
|
from django.utils.translation import gettext_lazy as _
|
|
|
|
|
|
def validate_even(value):
|
|
if value % 2 != 0:
|
|
raise ValidationError(
|
|
_("%(value)s is not an even number"),
|
|
params={"value": value},
|
|
)
|
|
|
|
You can add this to a model field via the field's
|
|
:attr:`~django.db.models.Field.validators` argument::
|
|
|
|
from django.db import models
|
|
|
|
|
|
class MyModel(models.Model):
|
|
even_field = models.IntegerField(validators=[validate_even])
|
|
|
|
Because values are converted to Python before validators are run, you can even
|
|
use the same validator with forms::
|
|
|
|
from django import forms
|
|
|
|
|
|
class MyForm(forms.Form):
|
|
even_field = forms.IntegerField(validators=[validate_even])
|
|
|
|
You can also use a class with a ``__call__()`` method for more complex or
|
|
configurable validators. :class:`RegexValidator`, for example, uses this
|
|
technique. If a class-based validator is used in the
|
|
:attr:`~django.db.models.Field.validators` model field option, you should make
|
|
sure it is :ref:`serializable by the migration framework
|
|
<migration-serializing>` by adding :ref:`deconstruct()
|
|
<custom-deconstruct-method>` and ``__eq__()`` methods.
|
|
|
|
How validators are run
|
|
======================
|
|
|
|
See the :doc:`form validation </ref/forms/validation>` for more information on
|
|
how validators are run in forms, and :ref:`Validating objects
|
|
<validating-objects>` for how they're run in models. Note that validators will
|
|
not be run automatically when you save a model, but if you are using a
|
|
:class:`~django.forms.ModelForm`, it will run your validators on any fields
|
|
that are included in your form. See the
|
|
:doc:`ModelForm documentation </topics/forms/modelforms>` for information on
|
|
how model validation interacts with forms.
|
|
|
|
Built-in validators
|
|
===================
|
|
|
|
The :mod:`django.core.validators` module contains a collection of callable
|
|
validators for use with model and form fields. They're used internally but
|
|
are available for use with your own fields, too. They can be used in addition
|
|
to, or in lieu of custom ``field.clean()`` methods.
|
|
|
|
``RegexValidator``
|
|
------------------
|
|
|
|
.. class:: RegexValidator(regex=None, message=None, code=None, inverse_match=None, flags=0)
|
|
|
|
:param regex: If not ``None``, overrides :attr:`regex`. Can be a regular
|
|
expression string or a pre-compiled regular expression.
|
|
:param message: If not ``None``, overrides :attr:`.message`.
|
|
:param code: If not ``None``, overrides :attr:`code`.
|
|
:param inverse_match: If not ``None``, overrides :attr:`inverse_match`.
|
|
:param flags: If not ``None``, overrides :attr:`flags`. In that case,
|
|
:attr:`regex` must be a regular expression string, or
|
|
:exc:`TypeError` is raised.
|
|
|
|
A :class:`RegexValidator` searches the provided ``value`` for a given
|
|
regular expression with :func:`re.search`. By default, raises a
|
|
:exc:`~django.core.exceptions.ValidationError` with :attr:`message` and
|
|
:attr:`code` if a match **is not** found. Its behavior can be inverted by
|
|
setting :attr:`inverse_match` to ``True``, in which case the
|
|
:exc:`~django.core.exceptions.ValidationError` is raised when a match
|
|
**is** found.
|
|
|
|
.. attribute:: regex
|
|
|
|
The regular expression pattern to search for within the provided
|
|
``value``, using :func:`re.search`. This may be a string or a
|
|
pre-compiled regular expression created with :func:`re.compile`.
|
|
Defaults to the empty string, which will be found in every possible
|
|
``value``.
|
|
|
|
.. attribute:: message
|
|
|
|
The error message used by
|
|
:exc:`~django.core.exceptions.ValidationError` if validation fails.
|
|
Defaults to ``"Enter a valid value"``.
|
|
|
|
.. attribute:: code
|
|
|
|
The error code used by :exc:`~django.core.exceptions.ValidationError`
|
|
if validation fails. Defaults to ``"invalid"``.
|
|
|
|
.. attribute:: inverse_match
|
|
|
|
The match mode for :attr:`regex`. Defaults to ``False``.
|
|
|
|
.. attribute:: flags
|
|
|
|
The :ref:`regex flags <python:contents-of-module-re>` used when
|
|
compiling the regular expression string :attr:`regex`. If :attr:`regex`
|
|
is a pre-compiled regular expression, and :attr:`flags` is overridden,
|
|
:exc:`TypeError` is raised. Defaults to ``0``.
|
|
|
|
``EmailValidator``
|
|
------------------
|
|
|
|
.. class:: EmailValidator(message=None, code=None, allowlist=None)
|
|
|
|
:param message: If not ``None``, overrides :attr:`.message`.
|
|
:param code: If not ``None``, overrides :attr:`code`.
|
|
:param allowlist: If not ``None``, overrides :attr:`allowlist`.
|
|
|
|
An :class:`EmailValidator` ensures that a value looks like an email, and
|
|
raises a :exc:`~django.core.exceptions.ValidationError` with
|
|
:attr:`message` and :attr:`code` if it doesn't. Values longer than 320
|
|
characters are always considered invalid.
|
|
|
|
.. attribute:: message
|
|
|
|
The error message used by
|
|
:exc:`~django.core.exceptions.ValidationError` if validation fails.
|
|
Defaults to ``"Enter a valid email address"``.
|
|
|
|
.. attribute:: code
|
|
|
|
The error code used by :exc:`~django.core.exceptions.ValidationError`
|
|
if validation fails. Defaults to ``"invalid"``.
|
|
|
|
.. attribute:: allowlist
|
|
|
|
Allowlist of email domains. By default, a regular expression (the
|
|
``domain_regex`` attribute) is used to validate whatever appears after
|
|
the ``@`` sign. However, if that string appears in the ``allowlist``,
|
|
this validation is bypassed. If not provided, the default ``allowlist``
|
|
is ``['localhost']``. Other domains that don't contain a dot won't pass
|
|
validation, so you'd need to add them to the ``allowlist`` as
|
|
necessary.
|
|
|
|
``DomainNameValidator``
|
|
-----------------------
|
|
|
|
.. class:: DomainNameValidator(accept_idna=True, message=None, code=None)
|
|
|
|
A :class:`RegexValidator` subclass that ensures a value looks like a domain
|
|
name. Values longer than 255 characters are always considered invalid. IP
|
|
addresses are not accepted as valid domain names.
|
|
|
|
In addition to the optional arguments of its parent :class:`RegexValidator`
|
|
class, ``DomainNameValidator`` accepts an extra optional attribute:
|
|
|
|
.. attribute:: accept_idna
|
|
|
|
Determines whether to accept internationalized domain names, that is,
|
|
domain names that contain non-ASCII characters. Defaults to ``True``.
|
|
|
|
``URLValidator``
|
|
----------------
|
|
|
|
.. class:: URLValidator(schemes=None, regex=None, message=None, code=None)
|
|
|
|
A :class:`RegexValidator` subclass that ensures a value looks like a URL,
|
|
and raises an error code of ``'invalid'`` if it doesn't. Values longer than
|
|
:attr:`max_length` characters are always considered invalid.
|
|
|
|
Loopback addresses and reserved IP spaces are considered valid. Literal
|
|
IPv6 addresses (:rfc:`3986#section-3.2.2`) and Unicode domains are both
|
|
supported.
|
|
|
|
In addition to the optional arguments of its parent :class:`RegexValidator`
|
|
class, ``URLValidator`` accepts an extra optional attribute:
|
|
|
|
.. attribute:: schemes
|
|
|
|
URL/URI scheme list to validate against. If not provided, the default
|
|
list is ``['http', 'https', 'ftp', 'ftps']``. As a reference, the IANA
|
|
website provides a full list of `valid URI schemes`_.
|
|
|
|
.. _valid URI schemes: https://www.iana.org/assignments/uri-schemes/uri-schemes.xhtml
|
|
|
|
.. warning::
|
|
|
|
Values starting with ``file:///`` will not pass validation even
|
|
when the ``file`` scheme is provided. Valid values must contain a
|
|
host.
|
|
|
|
.. attribute:: max_length
|
|
|
|
The maximum length of values that could be considered valid. Defaults
|
|
to 2048 characters.
|
|
|
|
``validate_email``
|
|
------------------
|
|
|
|
.. data:: validate_email
|
|
|
|
An :class:`EmailValidator` instance without any customizations.
|
|
|
|
``validate_domain_name``
|
|
------------------------
|
|
|
|
.. data:: validate_domain_name
|
|
|
|
A :class:`DomainNameValidator` instance without any customizations.
|
|
|
|
``validate_slug``
|
|
-----------------
|
|
|
|
.. data:: validate_slug
|
|
|
|
A :class:`RegexValidator` instance that ensures a value consists of only
|
|
letters, numbers, underscores or hyphens.
|
|
|
|
``validate_unicode_slug``
|
|
-------------------------
|
|
|
|
.. data:: validate_unicode_slug
|
|
|
|
A :class:`RegexValidator` instance that ensures a value consists of only
|
|
Unicode letters, numbers, underscores, or hyphens.
|
|
|
|
``validate_ipv4_address``
|
|
-------------------------
|
|
|
|
.. data:: validate_ipv4_address
|
|
|
|
A :class:`RegexValidator` instance that ensures a value looks like an IPv4
|
|
address.
|
|
|
|
``validate_ipv6_address``
|
|
-------------------------
|
|
|
|
.. data:: validate_ipv6_address
|
|
|
|
Uses ``django.utils.ipv6`` to check the validity of an IPv6 address.
|
|
|
|
``validate_ipv46_address``
|
|
--------------------------
|
|
|
|
.. data:: validate_ipv46_address
|
|
|
|
Uses both ``validate_ipv4_address`` and ``validate_ipv6_address`` to
|
|
ensure a value is either a valid IPv4 or IPv6 address.
|
|
|
|
``validate_comma_separated_integer_list``
|
|
-----------------------------------------
|
|
|
|
.. data:: validate_comma_separated_integer_list
|
|
|
|
A :class:`RegexValidator` instance that ensures a value is a
|
|
comma-separated list of integers.
|
|
|
|
``int_list_validator``
|
|
----------------------
|
|
|
|
.. function:: int_list_validator(sep=',', message=None, code='invalid', allow_negative=False)
|
|
|
|
Returns a :class:`RegexValidator` instance that ensures a string consists
|
|
of integers separated by ``sep``. It allows negative integers when
|
|
``allow_negative`` is ``True``.
|
|
|
|
``MaxValueValidator``
|
|
---------------------
|
|
|
|
.. class:: MaxValueValidator(limit_value, message=None)
|
|
|
|
Raises a :exc:`~django.core.exceptions.ValidationError` with a code of
|
|
``'max_value'`` if ``value`` is greater than ``limit_value``, which may be
|
|
a callable.
|
|
|
|
``MinValueValidator``
|
|
---------------------
|
|
|
|
.. class:: MinValueValidator(limit_value, message=None)
|
|
|
|
Raises a :exc:`~django.core.exceptions.ValidationError` with a code of
|
|
``'min_value'`` if ``value`` is less than ``limit_value``, which may be a
|
|
callable.
|
|
|
|
``MaxLengthValidator``
|
|
----------------------
|
|
|
|
.. class:: MaxLengthValidator(limit_value, message=None)
|
|
|
|
Raises a :exc:`~django.core.exceptions.ValidationError` with a code of
|
|
``'max_length'`` if the length of ``value`` is greater than
|
|
``limit_value``, which may be a callable.
|
|
|
|
``MinLengthValidator``
|
|
----------------------
|
|
|
|
.. class:: MinLengthValidator(limit_value, message=None)
|
|
|
|
Raises a :exc:`~django.core.exceptions.ValidationError` with a code of
|
|
``'min_length'`` if the length of ``value`` is less than ``limit_value``,
|
|
which may be a callable.
|
|
|
|
``DecimalValidator``
|
|
--------------------
|
|
|
|
.. class:: DecimalValidator(max_digits, decimal_places)
|
|
|
|
Raises :exc:`~django.core.exceptions.ValidationError` with the following
|
|
codes:
|
|
|
|
- ``'max_digits'`` if the number of digits is larger than ``max_digits``.
|
|
- ``'max_decimal_places'`` if the number of decimals is larger than
|
|
``decimal_places``.
|
|
- ``'max_whole_digits'`` if the number of whole digits is larger than
|
|
the difference between ``max_digits`` and ``decimal_places``.
|
|
|
|
``FileExtensionValidator``
|
|
--------------------------
|
|
|
|
.. class:: FileExtensionValidator(allowed_extensions, message, code)
|
|
|
|
Raises a :exc:`~django.core.exceptions.ValidationError` with a code of
|
|
``'invalid_extension'`` if the extension of ``value.name`` (``value`` is
|
|
a :class:`~django.core.files.File`) isn't found in ``allowed_extensions``.
|
|
The extension is compared case-insensitively with ``allowed_extensions``.
|
|
|
|
.. warning::
|
|
|
|
Don't rely on validation of the file extension to determine a file's
|
|
type. Files can be renamed to have any extension no matter what data
|
|
they contain.
|
|
|
|
``validate_image_file_extension``
|
|
---------------------------------
|
|
|
|
.. data:: validate_image_file_extension
|
|
|
|
Uses Pillow to ensure that ``value.name`` (``value`` is a
|
|
:class:`~django.core.files.File`) has `a valid image extension
|
|
<https://pillow.readthedocs.io/en/latest/handbook/image-file-formats.html>`__.
|
|
|
|
``ProhibitNullCharactersValidator``
|
|
-----------------------------------
|
|
|
|
.. class:: ProhibitNullCharactersValidator(message=None, code=None)
|
|
|
|
Raises a :exc:`~django.core.exceptions.ValidationError` if ``str(value)``
|
|
contains one or more null characters (``'\x00'``).
|
|
|
|
:param message: If not ``None``, overrides :attr:`.message`.
|
|
:param code: If not ``None``, overrides :attr:`code`.
|
|
|
|
.. attribute:: message
|
|
|
|
The error message used by
|
|
:exc:`~django.core.exceptions.ValidationError` if validation fails.
|
|
Defaults to ``"Null characters are not allowed."``.
|
|
|
|
.. attribute:: code
|
|
|
|
The error code used by :exc:`~django.core.exceptions.ValidationError`
|
|
if validation fails. Defaults to ``"null_characters_not_allowed"``.
|
|
|
|
``StepValueValidator``
|
|
----------------------
|
|
|
|
.. class:: StepValueValidator(limit_value, message=None, offset=None)
|
|
|
|
Raises a :exc:`~django.core.exceptions.ValidationError` with a code of
|
|
``'step_size'`` if ``value`` is not an integral multiple of
|
|
``limit_value``, which can be a float, integer or decimal value or a
|
|
callable. When ``offset`` is set, the validation occurs against
|
|
``limit_value`` plus ``offset``. For example, for
|
|
``StepValueValidator(3, offset=1.4)`` valid values include ``1.4``,
|
|
``4.4``, ``7.4``, ``10.4``, and so on.
|
|
|