WebsafeCharField for Django REST Framework

fields.py

class WebsafeCharField(serializers.CharField):
    """
    Like a regular CharField but does not allow certain characters.
    cannot contain / or \ or non-printable ASCII (0-31, 127)
    cannot contain non-characters from Unicode Plane 1 (U+FFFE and U+FFFF)
    cannot contain characters from Unicode Planes 2-16 (U+10000 through U+10FFFF)
    """
    default_error_messages = {
        'contains_unallowed_chars': _(r'Cannot contain non-printable ASCII, /, \, U+FFFE, U+FFFF, or U+10000 through U+10FFFF.'),
    }

    def __init__(self, *args, **kwargs):
        super(WebsafeCharField, self).__init__(*args, **kwargs)
        self.unallowed_char_regex = re.compile(u'[\x00-\x1f\x7f/\\\\\uFFFE-\U0010FFFF]', re.UNICODE)

    def from_native(self, value):
        value = super(WebsafeCharField, self).from_native(value)

        if isinstance(value, basestring):
            match = self.unallowed_char_regex.search(value)
            if match:
                raise ValidationError(self.error_messages['contains_unallowed_chars'])

        return value