Ticket #3961: za-localflavor.diff

django/utils/checksums.py

@@ +1 @@
+"""Implementations of useful checksum algorithms"""
+
+def luhn(s):
+    """A Luhn checksum is a simplistic checksum designed to catch typing
+    errors. Takes a string of digits or an int.
+
+    This checksum is commonly used with credit card numbers.
+
+    http://en.wikipedia.org/wiki/Luhn_algorithm
+    """
+
+    if isinstance(s, int):
+        s = str(s)
+
+    if not (isinstance(s, basestring) and s.isdigit()):
+        return False
+
+    lookup = (0, 2, 4, 6, 8, 1, 3, 5, 7, 9) # sum_of_digits(index * 2)
+    evens = sum([int(c) for c in s[-1::-2]])
+    odds = sum([lookup[int(c)] for c in s[-2::-2]])
+    return ((evens + odds) % 10 == 0)

django/contrib/localflavor/za/za_provinces.py

@@ +1 @@
+from django.utils.translation import gettext_lazy as _
+
+PROVINCE_CHOICES = (
+    ('EC', _('Eastern Cape')),
+    ('FS', _('Free State')),
+    ('GP', _('Gauteng')),
+    ('KN', _('KwaZulu-Natal')),
+    ('LP', _('Limpopo')),
+    ('MP', _('Mpumalanga')),
+    ('NC', _('Northern Cape')),
+    ('NW', _('North West')),
+    ('WC', _('Western Cape')),
+)

django/contrib/localflavor/za/forms.py

@@ +1 @@
+"""
+South Africa-specific Form helpers
+"""
+
+from django.newforms import ValidationError
+from django.newforms.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
+    """
+
+    def __init__(self, *args, **kwargs):
+        super(ZAIDField, self).__init__()
+        self.error_message = _(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_message)
+
+        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_message)
+
+        if not luhn(value):
+            raise ValidationError(self.error_message)
+
+        return value
+
+class ZAPostCodeField(RegexField):
+    def __init__(self, *args, **kwargs):
+        super(ZAPostCodeField, self).__init__(r'^\d{4}$',
+            max_length=None, min_length=None,
+            error_message=_(u'Enter a valid South African postal code'))

tests/regressiontests/forms/localflavor.py

@@ -882 +882 @@
 Traceback (most recent call last):
 ...
 ValidationError: [u'Enter a valid German identity card number in XXXXXXXXXXX-XXXXXXX-XXXXXXX-X format.']
+
+# ZAIDField #################################################################
+
+ZAIDField validates that the date is a valid birthdate and that the value
+has a valid checksum. It allows spaces and dashes, and returns a plain 
+string of digits.
+>>> from django.contrib.localflavor.za.forms import ZAIDField
+>>> f = ZAIDField()
+>>> f.clean('0002290001003')
+'0002290001003'
+>>> f.clean('000229 0001 003')
+'0002290001003'
+>>> f.clean('0102290001001')
+Traceback (most recent call last):
+...
+ValidationError: [u'Enter a valid South African ID number']
+>>> f.clean('811208')
+Traceback (most recent call last):
+...
+ValidationError: [u'Enter a valid South African ID number']
+>>> f.clean('0002290001004')
+Traceback (most recent call last):
+...
+ValidationError: [u'Enter a valid South African ID number']
+
+# ZAPostCodeField ###########################################################
+>>> from django.contrib.localflavor.za.forms import ZAPostCodeField
+>>> f = ZAPostCodeField()
+>>> f.clean('abcd')
+Traceback (most recent call last):
+...
+ValidationError: [u'Enter a valid South African postal code']
+>>> f.clean('0000')
+u'0000'
+>>> f.clean(' 7530')
+Traceback (most recent call last):
+...
+ValidationError: [u'Enter a valid South African postal code']
 """