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Source code for django.contrib.auth.password_validation

import functools
import gzip
import os
import re
from difflib import SequenceMatcher

from django.conf import settings
from django.core.exceptions import (
    FieldDoesNotExist, ImproperlyConfigured, ValidationError,
)
from django.utils.functional import lazy
from django.utils.html import format_html
from django.utils.module_loading import import_string
from django.utils.translation import gettext as _, ngettext


@functools.lru_cache(maxsize=None)
def get_default_password_validators():
    return get_password_validators(settings.AUTH_PASSWORD_VALIDATORS)


[docs]def get_password_validators(validator_config): validators = [] for validator in validator_config: try: klass = import_string(validator['NAME']) except ImportError: msg = "The module in NAME could not be imported: %s. Check your AUTH_PASSWORD_VALIDATORS setting." raise ImproperlyConfigured(msg % validator['NAME']) validators.append(klass(**validator.get('OPTIONS', {}))) return validators
[docs]def validate_password(password, user=None, password_validators=None): """ Validate whether the password meets all validator requirements. If the password is valid, return ``None``. If the password is invalid, raise ValidationError with all error messages. """ errors = [] if password_validators is None: password_validators = get_default_password_validators() for validator in password_validators: try: validator.validate(password, user) except ValidationError as error: errors.append(error) if errors: raise ValidationError(errors)
[docs]def password_changed(password, user=None, password_validators=None): """ Inform all validators that have implemented a password_changed() method that the password has been changed. """ if password_validators is None: password_validators = get_default_password_validators() for validator in password_validators: password_changed = getattr(validator, 'password_changed', lambda *a: None) password_changed(password, user)
[docs]def password_validators_help_texts(password_validators=None): """ Return a list of all help texts of all configured validators. """ help_texts = [] if password_validators is None: password_validators = get_default_password_validators() for validator in password_validators: help_texts.append(validator.get_help_text()) return help_texts
def _password_validators_help_text_html(password_validators=None): """ Return an HTML string with all help texts of all configured validators in an <ul>. """ help_texts = password_validators_help_texts(password_validators) help_items = [format_html('<li>{}</li>', help_text) for help_text in help_texts] return '<ul>%s</ul>' % ''.join(help_items) if help_items else '' password_validators_help_text_html = lazy(_password_validators_help_text_html, str)
[docs]class MinimumLengthValidator: """ Validate whether the password is of a minimum length. """ def __init__(self, min_length=8): self.min_length = min_length def validate(self, password, user=None): if len(password) < self.min_length: raise ValidationError( ngettext( "This password is too short. It must contain at least %(min_length)d character.", "This password is too short. It must contain at least %(min_length)d characters.", self.min_length ), code='password_too_short', params={'min_length': self.min_length}, ) def get_help_text(self): return ngettext( "Your password must contain at least %(min_length)d character.", "Your password must contain at least %(min_length)d characters.", self.min_length ) % {'min_length': self.min_length}
[docs]class UserAttributeSimilarityValidator: """ Validate whether the password is sufficiently different from the user's attributes. If no specific attributes are provided, look at a sensible list of defaults. Attributes that don't exist are ignored. Comparison is made to not only the full attribute value, but also its components, so that, for example, a password is validated against either part of an email address, as well as the full address. """ DEFAULT_USER_ATTRIBUTES = ('username', 'first_name', 'last_name', 'email') def __init__(self, user_attributes=DEFAULT_USER_ATTRIBUTES, max_similarity=0.7): self.user_attributes = user_attributes self.max_similarity = max_similarity def validate(self, password, user=None): if not user: return for attribute_name in self.user_attributes: value = getattr(user, attribute_name, None) if not value or not isinstance(value, str): continue value_parts = re.split(r'\W+', value) + [value] for value_part in value_parts: if SequenceMatcher(a=password.lower(), b=value_part.lower()).quick_ratio() >= self.max_similarity: try: verbose_name = str(user._meta.get_field(attribute_name).verbose_name) except FieldDoesNotExist: verbose_name = attribute_name raise ValidationError( _("The password is too similar to the %(verbose_name)s."), code='password_too_similar', params={'verbose_name': verbose_name}, ) def get_help_text(self): return _("Your password can't be too similar to your other personal information.")
[docs]class CommonPasswordValidator: """ Validate whether the password is a common password. The password is rejected if it occurs in a provided list, which may be gzipped. The list Django ships with contains 1000 common passwords, created by Mark Burnett: https://xato.net/passwords/more-top-worst-passwords/ """ DEFAULT_PASSWORD_LIST_PATH = os.path.join( os.path.dirname(os.path.realpath(__file__)), 'common-passwords.txt.gz' ) def __init__(self, password_list_path=DEFAULT_PASSWORD_LIST_PATH): try: with gzip.open(password_list_path) as f: common_passwords_lines = f.read().decode().splitlines() except IOError: with open(password_list_path) as f: common_passwords_lines = f.readlines() self.passwords = {p.strip() for p in common_passwords_lines} def validate(self, password, user=None): if password.lower().strip() in self.passwords: raise ValidationError( _("This password is too common."), code='password_too_common', ) def get_help_text(self): return _("Your password can't be a commonly used password.")
[docs]class NumericPasswordValidator: """ Validate whether the password is alphanumeric. """ def validate(self, password, user=None): if password.isdigit(): raise ValidationError( _("This password is entirely numeric."), code='password_entirely_numeric', ) def get_help_text(self): return _("Your password can't be entirely numeric.")
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