+
−"""
+
−South Africa-specific Form helpers
+
−"""
+
−
+
−from django.forms import ValidationError
+
−from django.forms.fields import Field, RegexField, EMPTY_VALUES
+
−from django.utils.checksums import luhn
+
−from django.utils.translation import gettext as _
+
−import re
+
−from datetime import date
+
−
+
−id_re = re.compile(r'^(?P<yy>\d\d)(?P<mm>\d\d)(?P<dd>\d\d)(?P<mid>\d{4})(?P<end>\d{3})')
+
−
+
−class ZAIDField(Field):
+
−    """A form field for South African ID numbers -- the checksum is validated
+
−    using the Luhn checksum, and uses a simlistic (read: not entirely accurate)
+
−    check for the birthdate
+
−    """
+
−    default_error_messages = {
+
−        'invalid': _(u'Enter a valid South African ID number'),
+
−    }
+
−
+
−    def clean(self, value):
+
−        # strip spaces and dashes
+
−        value = value.strip().replace(' ', '').replace('-', '')
+
−
+
−        super(ZAIDField, self).clean(value)
+
−
+
−        if value in EMPTY_VALUES:
+
−            return u''
+
−
+
−        match = re.match(id_re, value)
+
−
+
−        if not match:
+
−            raise ValidationError(self.error_messages['invalid'])
+
−
+
−        g = match.groupdict()
+
−
+
−        try:
+
−            # The year 2000 is conveniently a leapyear.
+
−            # This algorithm will break in xx00 years which aren't leap years
+
−            # There is no way to guess the century of a ZA ID number
+
−            d = date(int(g['yy']) + 2000, int(g['mm']), int(g['dd']))
+
−        except ValueError:
+
−            raise ValidationError(self.error_messages['invalid'])
+
−
+
−        if not luhn(value):
+
−            raise ValidationError(self.error_messages['invalid'])
+
−
+
−        return value
+
−
+
−class ZAPostCodeField(RegexField):
+
−    default_error_messages = {
+
−        'invalid': _(u'Enter a valid South African postal code'),
+
−    }
+
−
+
−    def __init__(self, *args, **kwargs):
+
−        super(ZAPostCodeField, self).__init__(r'^\d{4}$',
+
−            max_length=None, min_length=None)