Deprecate generic.checksums.luhn and ean

docs/changelog.rst

@@ -13,7 +13,7 @@ New fields for existing flavors:
 
 Modifications to existing flavors:
 
-- None
+- Deprecated `generic.checksums.luhn` and `generic.checksums.ean`. Please use the python-stdnum library instead.
 
 Other changes:
 

localflavor/ca/forms.py

@@ -8,8 +8,7 @@
 from django.forms import ValidationError
 from django.forms.fields import CharField, Field, Select
 from django.utils.translation import ugettext_lazy as _
-
-from localflavor.generic.checksums import luhn
+from stdnum import luhn
 
 sin_re = re.compile(r"^(\d{3})-(\d{3})-(\d{3})$")
 
@@ -113,6 +112,6 @@ def clean(self, value):
             match.group(1),
             match.group(2),
             match.group(3))
-        if not luhn(check_number):
+        if not luhn.is_valid(check_number):
             raise ValidationError(self.error_messages['invalid'])
         return number

localflavor/fr/forms.py

@@ -5,12 +5,10 @@
 import re
 from datetime import date
 
-from django.core.validators import EMPTY_VALUES
 from django.forms import ValidationError
 from django.forms.fields import CharField, RegexField, Select
 from django.utils.translation import ugettext_lazy as _
-
-from localflavor.generic.checksums import luhn
+from stdnum import luhn
 
 from .fr_department import DEPARTMENT_CHOICES_PER_REGION
 from .fr_region import REGION_2016_CHOICES, REGION_CHOICES
@@ -189,7 +187,7 @@ def clean(self, value):
             return self.empty_value
 
         value = value.replace(' ', '').replace('-', '')
-        if not self.r_valid.match(value) or not luhn(value):
+        if not self.r_valid.match(value) or not luhn.is_valid(value):
             raise ValidationError(self.error_messages['invalid'])
         return value
 
@@ -234,14 +232,15 @@ class FRSIRETField(FRSIRENENumberMixin, CharField):
     }
 
     def clean(self, value):
-        if value not in EMPTY_VALUES:
-            value = value.replace(' ', '').replace('-', '')
+        value = super(FRSIRETField, self).clean(value)
+        if value in self.empty_values:
+            return self.empty_value
 
-        ret = super(FRSIRETField, self).clean(value)
+        value = value.replace(' ', '').replace('-', '')
 
-        if ret is not None and not luhn(ret[:9]):
+        if not luhn.is_valid(value[:9]):
             raise ValidationError(self.error_messages['invalid'])
-        return ret
+        return value
 
     def prepare_value(self, value):
         if value is None:

localflavor/generic/checksums.py

@@ -1,10 +1,13 @@
 """Common checksum routines."""
+import warnings
+
 from django.utils import six
+from stdnum import ean as stdnum_ean
+from stdnum import luhn as stdnum_luhn
 
-__all__ = ['luhn', 'ean']
+from localflavor.deprecation import RemovedInLocalflavor30Warning
 
-LUHN_ODD_LOOKUP = (0, 2, 4, 6, 8, 1, 3, 5, 7, 9)  # sum_of_digits(index * 2)
-EAN_LOOKUP = (3, 1)
+__all__ = ['luhn', 'ean']
 
 
 def luhn(candidate):
@@ -13,15 +16,25 @@ def luhn(candidate):
 
     Luhn algorithm is used in validation of, for example, credit cards.
     Both numeric and string candidates are accepted.
+
+    .. deprecated:: 2.2
+       Use the luhn function in the python-stdnum_ library instead.
+
+    .. _python-stdnum: https://arthurdejong.org/python-stdnum/
     """
+    warnings.warn(
+        'luhn is deprecated in favor of the luhn function in the python-stdnum library.',
+        RemovedInLocalflavor30Warning,
+    )
+
     if not isinstance(candidate, six.string_types):
         candidate = str(candidate)
-    try:
-        evens = sum(int(c) for c in candidate[-1::-2])
-        odds = sum(LUHN_ODD_LOOKUP[int(c)] for c in candidate[-2::-2])
-        return ((evens + odds) % 10 == 0)
-    except ValueError:  # Raised if an int conversion fails
-        return False
+
+    # Our version returned True for empty strings.
+    if candidate == '':
+        return True
+
+    return stdnum_luhn.is_valid(candidate)
 
 
 def ean(candidate):
@@ -31,16 +44,18 @@ def ean(candidate):
     Note that this validator does not enforce any length checks (usually 13 or 8).
 
     http://en.wikipedia.org/wiki/International_Article_Number_(EAN)
+
+    .. deprecated:: 2.2
+       Use the ean function in the python-stdnum_ library instead.
+
+    .. _python-stdnum: https://arthurdejong.org/python-stdnum/
     """
+    warnings.warn(
+        'ean is deprecated in favor of the ean function in the python-stdnum library.',
+        RemovedInLocalflavor30Warning,
+    )
+
     if not isinstance(candidate, six.string_types):
         candidate = str(candidate)
-    if len(candidate) <= 1:
-        return False
-    given_number, given_checksum = candidate[:-1], candidate[-1]
-    try:
-        calculated_checksum = sum(
-            int(digit) * EAN_LOOKUP[i % 2] for i, digit in enumerate(reversed(given_number)))
-        calculated_checksum = 9 - ((calculated_checksum - 1) % 10)
-        return str(calculated_checksum) == given_checksum
-    except ValueError:  # Raised if an int conversion fails
-        return False
+
+    return stdnum_ean.is_valid(candidate)

localflavor/generic/validators.py

@@ -7,8 +7,8 @@
 from django.core.exceptions import ImproperlyConfigured, ValidationError
 from django.utils.deconstruct import deconstructible
 from django.utils.translation import ugettext_lazy as _
+from stdnum import ean
 
-from . import checksums
 from .countries.iso_3166 import ISO_3166_1_ALPHA2_COUNTRY_CODES
 
 # Dictionary of ISO country code to IBAN length.
@@ -272,7 +272,7 @@ def __call__(self, value):
             return value
         if self.strip_nondigits:
             value = re.compile(r'[^\d]+').sub('', value)
-        if not checksums.ean(value):
+        if not ean.is_valid(value):
             raise ValidationError(self.message, code='invalid')
 
 

localflavor/gr/forms.py

@@ -6,8 +6,7 @@
 from django.forms import Field, RegexField, ValidationError
 from django.utils.encoding import force_text
 from django.utils.translation import ugettext_lazy as _
-
-from localflavor.generic.checksums import luhn
+from stdnum import luhn
 
 
 class GRPostalCodeField(RegexField):
@@ -100,7 +99,7 @@ def clean(self, value):
             raise ValidationError(self.error_messages['invalid'])
 
         self.check_date(val)
-        if not luhn(val):
+        if not luhn.is_valid(val):
             raise ValidationError(self.error_messages['invalid'])
 
         return val

localflavor/hr/forms.py

@@ -10,8 +10,7 @@
 from django.forms.fields import Field, RegexField, Select
 from django.utils.encoding import force_text
 from django.utils.translation import ugettext_lazy as _
-
-from localflavor.generic.checksums import luhn
+from stdnum import luhn
 
 from .hr_choices import HR_COUNTY_CHOICES, HR_LICENSE_PLATE_PREFIX_CHOICES
 
@@ -227,7 +226,7 @@ def clean(self, value):
             raise ValidationError(self.error_messages['copy'])
 
         # Validate checksum using Luhn algorithm.
-        if not luhn(value):
+        if not luhn.is_valid(value):
             raise ValidationError(self.error_messages['invalid'])
 
         return '%s' % value

localflavor/il/forms.py

@@ -7,8 +7,7 @@
 from django.core.validators import EMPTY_VALUES
 from django.forms.fields import Field, RegexField
 from django.utils.translation import ugettext_lazy as _
-
-from localflavor.generic.checksums import luhn
+from stdnum import luhn
 
 id_number_re = re.compile(r'^(?P<number>\d{1,8})-?(?P<check>\d)$')
 
@@ -66,6 +65,6 @@ def clean(self, value):
             raise ValidationError(self.error_messages['invalid'])
 
         value = match.group('number') + match.group('check')
-        if not luhn(value):
+        if not luhn.is_valid(value):
             raise ValidationError(self.error_messages['invalid'])
         return value

localflavor/za/forms.py

@@ -7,8 +7,7 @@
 from django.forms import ValidationError
 from django.forms.fields import CharField, RegexField, Select
 from django.utils.translation import gettext_lazy as _
-
-from localflavor.generic.checksums import luhn
+from stdnum import luhn
 
 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})')
 
@@ -49,7 +48,7 @@ def clean(self, value):
         except ValueError:
             raise ValidationError(self.error_messages['invalid'])
 
-        if not luhn(value):
+        if not luhn.is_valid(value):
             raise ValidationError(self.error_messages['invalid'])
 
         return value

setup.py

@@ -119,7 +119,10 @@ def find_package_data(where='.', package='',
     author_email='foundation@djangoproject.com',
     packages=find_packages(exclude=['tests', 'tests.*']),
     package_data=find_package_data(),
-    install_requires=['django>=1.11'],
+    install_requires=[
+        'django>=1.11',
+        'python-stdnum>=1.0',
+    ],
     classifiers=[
         'Development Status :: 5 - Production/Stable',
         'Environment :: Web Environment',