"""
South Africa-specific Form helpers
"""
from django.core.validators import EMPTY_VALUES
from django.forms import ValidationError
from django.forms.fields import Field,RegexField
from django.utils.checksums import luhn
from django.utils.translation import gettext
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)
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