Add cover with logos.

[wolnelektury.git] / apps / newtagging / models.py

diff --git a/apps/newtagging/models.py b/apps/newtagging/models.py
index 5385e95..7e0f949 100644 (file)
--- a/apps/newtagging/models.py
+++ b/apps/newtagging/models.py
@@ -1,8 +1,12 @@
+# -*- coding: utf-8 -*-

 """
 Models and managers for generic tagging.
 """
 """
 Models and managers for generic tagging.
 """

+

 # Python 2.3 compatibility
 # Python 2.3 compatibility

-if not hasattr(__builtins__, 'set'):
+try:
+    set
+except NameError:

     from sets import Set as set
 
 from django.contrib.contenttypes import generic
     from sets import Set as set
 
 from django.contrib.contenttypes import generic


@@ -10,6 +14,8 @@ from django.contrib.contenttypes.models import ContentType
 from django.db import connection, models
 from django.utils.translation import ugettext_lazy as _
 from django.db.models.base import ModelBase
 from django.db import connection, models
 from django.utils.translation import ugettext_lazy as _
 from django.db.models.base import ModelBase

+from django.core.exceptions import ObjectDoesNotExist
+from django.dispatch import Signal

 
 qn = connection.ops.quote_name
 
 
 qn = connection.ops.quote_name
 


@@ -19,6 +25,8 @@ except ImportError:
     parse_lookup = None
 
 
     parse_lookup = None
 
 

+tags_updated = Signal(providing_args=["affected_tags"])
+

 def get_queryset_and_model(queryset_or_model):
     """
     Given a ``QuerySet`` or a ``Model``, returns a two-tuple of
 def get_queryset_and_model(queryset_or_model):
     """
     Given a ``QuerySet`` or a ``Model``, returns a two-tuple of


@@ -40,7 +48,17 @@ class TagManager(models.Manager):
     def __init__(self, intermediary_table_model):
         super(TagManager, self).__init__()
         self.intermediary_table_model = intermediary_table_model
     def __init__(self, intermediary_table_model):
         super(TagManager, self).__init__()
         self.intermediary_table_model = intermediary_table_model

-    
+        models.signals.pre_delete.connect(self.target_deleted)
+
+    def target_deleted(self, instance, **kwargs):
+        """ clear tag relations before deleting an object """
+        try:
+            int(instance.pk)
+        except ValueError:
+            return
+
+        self.update_tags(instance, [])
+

     def update_tags(self, obj, tags):
         """
         Update tags associated with an object.
     def update_tags(self, obj, tags):
         """
         Update tags associated with an object.


@@ -49,7 +67,7 @@ class TagManager(models.Manager):
         current_tags = list(self.filter(items__content_type__pk=content_type.pk,
                                         items__object_id=obj.pk))
         updated_tags = self.model.get_tag_list(tags)
         current_tags = list(self.filter(items__content_type__pk=content_type.pk,
                                         items__object_id=obj.pk))
         updated_tags = self.model.get_tag_list(tags)

-    
+

         # Remove tags which no longer apply
         tags_for_removal = [tag for tag in current_tags \
                             if tag not in updated_tags]
         # Remove tags which no longer apply
         tags_for_removal = [tag for tag in current_tags \
                             if tag not in updated_tags]


@@ -58,10 +76,22 @@ class TagManager(models.Manager):
                                                object_id=obj.pk,
                                                tag__in=tags_for_removal).delete()
         # Add new tags
                                                object_id=obj.pk,
                                                tag__in=tags_for_removal).delete()
         # Add new tags

-        for tag in updated_tags:
+        tags_to_add = [tag for tag in updated_tags
+                       if tag not in current_tags]
+        for tag in tags_to_add:

             if tag not in current_tags:
                 self.intermediary_table_model._default_manager.create(tag=tag, content_object=obj)
             if tag not in current_tags:
                 self.intermediary_table_model._default_manager.create(tag=tag, content_object=obj)

-    
+
+        tags_updated.send(sender=obj, affected_tags=tags_to_add + tags_for_removal)
+
+    def remove_tag(self, obj, tag):
+        """
+        Remove tag from an object.
+        """
+        content_type = ContentType.objects.get_for_model(obj)
+        self.intermediary_table_model._default_manager.filter(content_type__pk=content_type.pk,
+            object_id=obj.pk, tag=tag).delete()
+

     def get_for_object(self, obj):
         """
         Create a queryset matching all tags associated with the given
     def get_for_object(self, obj):
         """
         Create a queryset matching all tags associated with the given


@@ -70,7 +100,7 @@ class TagManager(models.Manager):
         ctype = ContentType.objects.get_for_model(obj)
         return self.filter(items__content_type__pk=ctype.pk,
                            items__object_id=obj.pk)
         ctype = ContentType.objects.get_for_model(obj)
         return self.filter(items__content_type__pk=ctype.pk,
                            items__object_id=obj.pk)

-    
+

     def _get_usage(self, model, counts=False, min_count=None, extra_joins=None, extra_criteria=None, params=None, extra=None):
         """
         Perform the custom SQL query for ``usage_for_model`` and
     def _get_usage(self, model, counts=False, min_count=None, extra_joins=None, extra_criteria=None, params=None, extra=None):
         """
         Perform the custom SQL query for ``usage_for_model`` and


@@ -81,12 +111,12 @@ class TagManager(models.Manager):
         model_table = qn(model._meta.db_table)
         model_pk = '%s.%s' % (model_table, qn(model._meta.pk.column))
         tag_columns = self._get_tag_columns()
         model_table = qn(model._meta.db_table)
         model_pk = '%s.%s' % (model_table, qn(model._meta.pk.column))
         tag_columns = self._get_tag_columns()

-        
+

         if extra is None: extra = {}
         extra_where = ''
         if 'where' in extra:
             extra_where = 'AND ' + ' AND '.join(extra['where'])
         if extra is None: extra = {}
         extra_where = ''
         if 'where' in extra:
             extra_where = 'AND ' + ' AND '.join(extra['where'])

-        
+

         query = """
         SELECT DISTINCT %(tag_columns)s%(count_sql)s
         FROM
         query = """
         SELECT DISTINCT %(tag_columns)s%(count_sql)s
         FROM


@@ -99,7 +129,7 @@ class TagManager(models.Manager):
         WHERE %(tagged_item)s.content_type_id = %(content_type_id)s
             %%s
             %(extra_where)s
         WHERE %(tagged_item)s.content_type_id = %(content_type_id)s
             %%s
             %(extra_where)s

-        GROUP BY %(tag)s.id, %(tag)s.name
+        GROUP BY %(tag_columns)s, %(tag)s.id, %(tag)s.name

         %%s
         ORDER BY %(tag)s.%(ordering)s ASC""" % {
             'tag': qn(self.model._meta.db_table),
         %%s
         ORDER BY %(tag)s.%(ordering)s ASC""" % {
             'tag': qn(self.model._meta.db_table),


@@ -185,8 +215,18 @@ class TagManager(models.Manager):
         if parse_lookup:
             raise AttributeError("'TagManager.usage_for_queryset' is not compatible with pre-queryset-refactor versions of Django.")
 
         if parse_lookup:
             raise AttributeError("'TagManager.usage_for_queryset' is not compatible with pre-queryset-refactor versions of Django.")
 

-        extra_joins = ' '.join(queryset.query.get_from_clause()[0][1:])
-        where, params = queryset.query.where.as_sql()
+        if getattr(queryset.query, 'get_compiler', None):
+            # Django 1.2+
+            compiler = queryset.query.get_compiler(using='default')
+            extra_joins = ' '.join(compiler.get_from_clause()[0][1:])
+            where, params = queryset.query.where.as_sql(
+                compiler.quote_name_unless_alias, compiler.connection
+            )
+        else:
+            # Django pre-1.2
+            extra_joins = ' '.join(queryset.query.get_from_clause()[0][1:])
+            where, params = queryset.query.where.as_sql()
+

         if where:
             extra_criteria = 'AND %s' % where
         else:
         if where:
             extra_criteria = 'AND %s' % where
         else:


@@ -211,28 +251,33 @@ class TagManager(models.Manager):
         tag_count = len(tags)
         tagged_item_table = qn(self.intermediary_table_model._meta.db_table)
         tag_columns = self._get_tag_columns()
         tag_count = len(tags)
         tagged_item_table = qn(self.intermediary_table_model._meta.db_table)
         tag_columns = self._get_tag_columns()

-        
+

         if extra is None: extra = {}
         extra_where = ''
         if 'where' in extra:
             extra_where = 'AND ' + ' AND '.join(extra['where'])
         if extra is None: extra = {}
         extra_where = ''
         if 'where' in extra:
             extra_where = 'AND ' + ' AND '.join(extra['where'])

-        
+
+        # Temporary table in this query is a hack to prevent MySQL from executing
+        # inner query as dependant query (which could result in severe performance loss)

         query = """
         SELECT %(tag_columns)s%(count_sql)s
         FROM %(tagged_item)s INNER JOIN %(tag)s ON %(tagged_item)s.tag_id = %(tag)s.id
         WHERE %(tagged_item)s.content_type_id = %(content_type_id)s
         query = """
         SELECT %(tag_columns)s%(count_sql)s
         FROM %(tagged_item)s INNER JOIN %(tag)s ON %(tagged_item)s.tag_id = %(tag)s.id
         WHERE %(tagged_item)s.content_type_id = %(content_type_id)s

-          AND %(tagged_item)s.object_id IN
-          (
-              SELECT %(tagged_item)s.object_id
-              FROM %(tagged_item)s, %(tag)s
-              WHERE %(tagged_item)s.content_type_id = %(content_type_id)s
-                AND %(tag)s.id = %(tagged_item)s.tag_id
-                AND %(tag)s.id IN (%(tag_id_placeholders)s)
-              GROUP BY %(tagged_item)s.object_id
-              HAVING COUNT(%(tagged_item)s.object_id) = %(tag_count)s
-          )
-          AND %(tag)s.id NOT IN (%(tag_id_placeholders)s)
-          %(extra_where)s
+        AND %(tagged_item)s.object_id IN
+        (
+            SELECT *
+            FROM (
+                SELECT %(tagged_item)s.object_id
+                FROM %(tagged_item)s, %(tag)s
+                WHERE %(tagged_item)s.content_type_id = %(content_type_id)s
+                  AND %(tag)s.id = %(tagged_item)s.tag_id
+                  AND %(tag)s.id IN (%(tag_id_placeholders)s)
+                GROUP BY %(tagged_item)s.object_id
+                HAVING COUNT(%(tagged_item)s.object_id) = %(tag_count)s
+            ) AS temporary
+        )
+        AND %(tag)s.id NOT IN (%(tag_id_placeholders)s)
+        %(extra_where)s

         GROUP BY %(tag_columns)s
         %(min_count_sql)s
         ORDER BY %(tag)s.%(ordering)s ASC""" % {
         GROUP BY %(tag_columns)s
         %(min_count_sql)s
         ORDER BY %(tag)s.%(ordering)s ASC""" % {


@@ -283,7 +328,7 @@ class TaggedItemManager(models.Manager):
     def __init__(self, tag_model):
         super(TaggedItemManager, self).__init__()
         self.tag_model = tag_model
     def __init__(self, tag_model):
         super(TaggedItemManager, self).__init__()
         self.tag_model = tag_model

-    
+

     def get_by_model(self, queryset_or_model, tags):
         """
         Create a ``QuerySet`` containing instances of the specified
     def get_by_model(self, queryset_or_model, tags):
         """
         Create a ``QuerySet`` containing instances of the specified


@@ -394,7 +439,7 @@ class TaggedItemManager(models.Manager):
         else:
             return model._default_manager.none()
 
         else:
             return model._default_manager.none()
 

-    def get_related(self, obj, queryset_or_model, num=None):
+    def get_related(self, obj, queryset_or_model, num=None, ignore_by_tag=None):

         """
         Retrieve a list of instances of the specified model which share
         tags with the model instance ``obj``, ordered by the number of
         """
         Retrieve a list of instances of the specified model which share
         tags with the model instance ``obj``, ordered by the number of


@@ -402,6 +447,8 @@ class TaggedItemManager(models.Manager):
 
         If ``num`` is given, a maximum of ``num`` instances will be
         returned.
 
         If ``num`` is given, a maximum of ``num`` instances will be
         returned.

+
+        If ``ignore_by_tag`` is given, object tagged with it will be ignored.

         """
         queryset, model = get_queryset_and_model(queryset_or_model)
         model_table = qn(model._meta.db_table)
         """
         queryset, model = get_queryset_and_model(queryset_or_model)
         model_table = qn(model._meta.db_table)


@@ -421,6 +468,15 @@ class TaggedItemManager(models.Manager):
             # instances for the same model.
             query += """
           AND related_tagged_item.object_id != %(tagged_item)s.object_id"""
             # instances for the same model.
             query += """
           AND related_tagged_item.object_id != %(tagged_item)s.object_id"""

+        if ignore_by_tag is not None:
+            query += """
+                AND NOT EXISTS (
+                    SELECT * FROM %(tagged_item)s
+                        WHERE %(tagged_item)s.object_id = %(model_pk)s
+                          AND %(tagged_item)s.content_type_id = %(content_type_id)s
+                          AND %(ignore_id)s = %(tagged_item)s.tag_id
+                )
+            """

         query += """
         GROUP BY %(model_pk)s
         ORDER BY %(count)s DESC
         query += """
         GROUP BY %(model_pk)s
         ORDER BY %(count)s DESC


@@ -434,6 +490,7 @@ class TaggedItemManager(models.Manager):
             'content_type_id': content_type.pk,
             'related_content_type_id': related_content_type.pk,
             'limit_offset': num is not None and connection.ops.limit_offset_sql(num) or '',
             'content_type_id': content_type.pk,
             'related_content_type_id': related_content_type.pk,
             'limit_offset': num is not None and connection.ops.limit_offset_sql(num) or '',

+            'ignore_id': ignore_by_tag.id if ignore_by_tag else None,

         }
 
         cursor = connection.cursor()
         }
 
         cursor = connection.cursor()


@@ -455,15 +512,19 @@ class TaggedItemManager(models.Manager):
 def create_intermediary_table_model(model):
     """Create an intermediary table model for the specific tag model"""
     name = model.__name__ + 'Relation'
 def create_intermediary_table_model(model):
     """Create an intermediary table model for the specific tag model"""
     name = model.__name__ + 'Relation'

-     
+

     class Meta:
         db_table = '%s_relation' % model._meta.db_table
         unique_together = (('tag', 'content_type', 'object_id'),)
     class Meta:
         db_table = '%s_relation' % model._meta.db_table
         unique_together = (('tag', 'content_type', 'object_id'),)

+        app_label = model._meta.app_label

 
     def obj_unicode(self):
 
     def obj_unicode(self):

-        return u'%s [%s]' % (self.content_type.get_object_for_this_type(pk=self.object_id), self.tag)
-        
-    # Set up a dictionary to simulate declarations within a class    
+        try:
+            return u'%s [%s]' % (self.content_type.get_object_for_this_type(pk=self.object_id), self.tag)
+        except ObjectDoesNotExist:
+            return u'<deleted> [%s]' % self.tag
+
+    # Set up a dictionary to simulate declarations within a class

     attrs = {
         '__module__': model.__module__,
         'Meta': Meta,
     attrs = {
         '__module__': model.__module__,
         'Meta': Meta,


@@ -492,15 +553,15 @@ class TagMeta(ModelBase):
 class TagBase(models.Model):
     """Abstract class to be inherited by model classes."""
     __metaclass__ = TagMeta
 class TagBase(models.Model):
     """Abstract class to be inherited by model classes."""
     __metaclass__ = TagMeta

-    
+

     class Meta:
         abstract = True
     class Meta:
         abstract = True

-    
+

     @staticmethod
     def get_tag_list(tag_list):
         """
         Utility function for accepting tag input in a flexible manner.
     @staticmethod
     def get_tag_list(tag_list):
         """
         Utility function for accepting tag input in a flexible manner.

-        
+

         You should probably override this method in your subclass.
         """
         if isinstance(tag_list, TagBase):
         You should probably override this method in your subclass.
         """
         if isinstance(tag_list, TagBase):