CleanCharField

from django import newforms as forms
from django.conf import settings
from django.newforms.fields import EMPTY_VALUES
from django.utils.translation import ugettext as _, ungettext

from utils.BeautifulSoup import BeautifulSoup, Comment


class CleanCharField(forms.CharField):
	valid_tags= settings.VALID_TAGS.split()
	valid_attrs= settings.VALID_ATTRS.split()

	def clean(self, value):
		"""
			Checks that the given string has no profanities in it. This does a simple
			check for whether each profanity exists within the string, so 'fuck' will
			catch 'motherfucker' as well. Raises a ValidationError such as:
			Watch your mouth! The words "f--k" and "s--t" are not allowed here.
		"""
		value= value.lower() # normalize
		words_seen= [w for w in settings.PROFANITIES_LIST if w in value]
		if words_seen:
			from django.utils.text import get_text_list
			plural= len(words_seen)
			raise forms.ValidationError, ungettext("Watch your mouth! The word %s is not allowed here.",
				"Watch your mouth! The words %s are not allowed here.", plural) % \
				get_text_list(['"%s%s%s"' % (i[0], '-'*(len(i)-2), i[-1]) for i in words_seen], _('and'))
		"""
			Cleans non-allowed HTML from the input
		"""
		value= super(CleanCharField, self).clean(value)
		soup= BeautifulSoup(value)
		for comment in soup.findAll(text=lambda text: isinstance(text, Comment)):
			comment.extract()
		for tag in soup.findAll(True):
			if tag.name not in self.valid_tags:
				tag.hidden= True
				tag.attrs= [(attr, val) for attr, val in tag.attrs if attr in self.valid_attrs]
		return soup.renderContents().decode('utf8')


settings.py:
PROFANITIES_LIST = ('asshat', 'asshead', 'asshole', 'cunt', 'fuck', 'gook', 'nigger', 'shit',)
VALID_TAGS= 'p i strong b u a h1 h2 h3 pre br img'
VALID_ATTRS= 'href src'