Implemented configurable forcing of tags to lowercase before they are…

… saved to the database

docs/overview.txt

@@ -47,6 +47,23 @@ creates permission objects for all installed apps that need them.
 That's it!
 
 
+Settings
+========
+
+Some of django-tagging's behaviour may be configured by adding the
+appropriate settings to your project's settings file.
+
+The following settings are available:
+
+FORCE_LOWERCASE_TAGS
+--------------------
+
+Default: ``False``
+
+A boolean that turns on/off forcing of tags to lowercase before they
+are saved to the database.
+
+
 Tags
 ====
 

tagging/fields.py

@@ -2,6 +2,7 @@
 from django.db.models.fields import CharField
 from django.dispatch import dispatcher
 
+from tagging import settings
 from tagging.models import Tag
 from tagging.validators import isTagList
 
@@ -63,7 +64,10 @@ def __set__(self, instance, value):
         """
         if instance is None:
             raise AttributeError('%s can only be set on instances.' % self.name)
-        self._set_instance_tag_cache(instance, value)
+        if settings.FORCE_LOWERCASE_TAGS:
+            self._set_instance_tag_cache(instance, value.lower())
+        else:
+            self._set_instance_tag_cache(instance, value)
 
     def _save(self, signal, sender, instance):
         """
@@ -87,7 +91,7 @@ def _get_instance_tag_cache(self, instance):
 
     def _set_instance_tag_cache(self, instance, tags):
         """
-        Helper: set and instance's tag cache.
+        Helper: set an instance's tag cache.
         """
         setattr(instance, '_%s_cache' % self.attname, tags)
 

tagging/managers.py

@@ -8,6 +8,7 @@
 from django.db.models.query import QuerySet, parse_lookup
 from django.contrib.contenttypes.models import ContentType
 
+from tagging import settings
 from tagging.utils import calculate_cloud, get_tag_name_list, get_tag_list, LOGARITHMIC
 
 # Python 2.3 compatibility
@@ -25,6 +26,8 @@ def update_tags(self, obj, tag_names):
         current_tags = list(self.filter(items__content_type__pk=ctype.id,
                                         items__object_id=obj._get_pk_val()))
         updated_tag_names = set(get_tag_name_list(tag_names))
+        if settings.FORCE_LOWERCASE_TAGS:
+            updated_tag_names = [t.lower() for t in updated_tag_names]
 
         TaggedItemModel = self._get_related_model_by_accessor('items')
 

tagging/settings.py

@@ -0,0 +1,13 @@
+"""
+Convenience module for access of custom tagging application settings,
+which enforces default settings when the main settings module which has
+been configured does not contain the appropriate settings.
+"""
+from django.conf import settings
+
+# Whether to force all tags to lowercase before they are saved to the
+# database. Default is False.
+try:
+    FORCE_LOWERCASE_TAGS = settings.FORCE_LOWERCASE_TAGS
+except AttributeError:
+    FORCE_LOWERCASE_TAGS = False

tagging/tests/tests.py

@@ -2,6 +2,7 @@
 r"""
 >>> import os
 >>> from django import newforms as forms
+>>> from tagging import settings
 >>> from tagging.models import Tag, TaggedItem
 >>> from tagging.tests.models import Article, Link, Perch, Parrot, FormTest
 >>> from tagging.utils import calculate_cloud, get_tag_name_list, get_tag_list, get_tag, LINEAR
@@ -217,6 +218,22 @@
 >>> Tag.objects.get_for_object(f1)
 []
 
+# Forcing tags to lowercase
+>>> settings.FORCE_LOWERCASE_TAGS = True
+>>> Tag.objects.update_tags(dead, 'foO bAr Ter')
+>>> Tag.objects.get_for_object(dead)
+[<Tag: bar>, <Tag: foo>, <Tag: ter>]
+>>> Tag.objects.update_tags(dead, 'foO bAr baZ')
+>>> Tag.objects.get_for_object(dead)
+[<Tag: bar>, <Tag: baz>, <Tag: foo>]
+>>> Tag.objects.update_tags(dead, None)
+>>> f1.tags = u'TEST5'
+>>> f1.save()
+>>> Tag.objects.get_for_object(f1)
+[<Tag: test5>]
+>>> f1.tags
+u'test5'
+
 # Retrieving tags by Model ####################################################
 
 >>> Tag.objects.usage_for_model(Parrot)