Fixed #3919 -- Added German identity card number validation to German

localflavor. Thanks, Jannis Leidel.


git-svn-id: http://code.djangoproject.com/svn/django/trunk@4922 bcc190cf-cafb-0310-a4f2-bffc1f526a37

1 files changed, 64 insertions, 0 deletions

diff --git a/django/contrib/localflavor/de/forms.py b/django/contrib/localflavor/de/forms.py
index 7e1bee5b4e..c82d2d5b8d 100644
--- a/django/contrib/localflavor/de/forms.py
+++ b/django/contrib/localflavor/de/forms.py
@@ -7,6 +7,8 @@ from django.newforms.fields import Field, RegexField, Select, EMPTY_VALUES
 from django.utils.translation import gettext
 import re
 
+id_re = re.compile(r"^(?P<residence>\d{10})(?P<origin>\w{1,3})[-\ ]?(?P<birthday>\d{7})[-\ ]?(?P<validity>\d{7})[-\ ]?(?P<checksum>\d{1})$")
+
 class DEZipCodeField(RegexField):
     def __init__(self, *args, **kwargs):
         super(DEZipCodeField, self).__init__(r'^\d{5}$',
@@ -21,3 +23,65 @@ class DEStateSelect(Select):
     def __init__(self, attrs=None):
         from de_states import STATE_CHOICES # relative import
         super(DEStateSelect, self).__init__(attrs, choices=STATE_CHOICES)
+
+class DEIdentityCardNumberField(Field):
+    """
+    A German identity card number.
+
+    Checks the following rules to determine whether the number is valid:
+
+        * Conforms to the XXXXXXXXXXX-XXXXXXX-XXXXXXX-X format.
+        * No group consists entirely of zeroes.
+        * Included checksums match calculated checksums
+
+    Algorithm is documented at http://de.wikipedia.org/wiki/Personalausweis
+    """
+    def has_valid_checksum(self, number):
+        given_number, given_checksum = number[:-1], number[-1]
+        calculated_checksum = 0
+        fragment = ""
+        parameter = 7
+
+        for i in range(len(given_number)):
+          fragment = str(int(given_number[i])*parameter)
+          if fragment.isalnum():
+            calculated_checksum += int(fragment[-1])
+
+          if parameter == 1:
+            parameter = 7
+          elif parameter == 3:
+            parameter = 1
+          elif parameter ==7:
+            parameter = 3
+
+        if str(calculated_checksum)[-1] == given_checksum:
+            return True
+        return False
+
+    def clean(self, value):
+        super(DEIdentityCardNumberField, self).clean(value)
+        error_msg = gettext(u'Enter a valid German identity card number in XXXXXXXXXXX-XXXXXXX-XXXXXXX-X format')
+        if value in EMPTY_VALUES:
+            return u''
+        match = re.match(id_re, value)
+        if not match:
+            raise ValidationError(error_msg)
+
+        residence, origin, birthday, validity, checksum = \
+        match.groupdict()['residence'], match.groupdict()['origin'], \
+        match.groupdict()['birthday'], match.groupdict()['validity'], \
+        match.groupdict()['checksum']
+
+        if residence == '0000000000' or \
+           birthday == '0000000' or \
+           validity == '0000000':
+            raise ValidationError(error_msg)
+
+        all_digits = "%s%s%s%s" % (residence, birthday, validity, checksum)
+        if not self.has_valid_checksum(residence) or \
+            not self.has_valid_checksum(birthday) or \
+            not self.has_valid_checksum(validity) or \
+            not self.has_valid_checksum(all_digits):
+                raise ValidationError(error_msg)
+
+        return u'%s%s-%s-%s-%s' % (residence, origin, birthday, validity, checksum)