newtagging refactor

diff --git a/apps/newtagging/models.py b/apps/newtagging/models.py
index 7e0f949..71cae93 100644 (file)
--- a/apps/newtagging/models.py
+++ b/apps/newtagging/models.py
@@ -3,27 +3,17 @@
 Models and managers for generic tagging.
 """
 
 Models and managers for generic tagging.
 """
 

-# Python 2.3 compatibility
-try:
-    set
-except NameError:
-    from sets import Set as set
-

 from django.contrib.contenttypes import generic
 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.contrib.contenttypes import generic
 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.models.loading import get_model # D1.7: apps?

 from django.core.exceptions import ObjectDoesNotExist
 from django.dispatch import Signal
 
 qn = connection.ops.quote_name
 
 from django.core.exceptions import ObjectDoesNotExist
 from django.dispatch import Signal
 
 qn = connection.ops.quote_name
 

-try:
-    from django.db.models.query import parse_lookup
-except ImportError:
-    parse_lookup = None
-

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


@@ -101,64 +91,7 @@ class TagManager(models.Manager):
         return self.filter(items__content_type__pk=ctype.pk,
                            items__object_id=obj.pk)
 
         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
-        ``usage_for_queryset``.
-        """
-        if min_count is not None: counts = True
-
-        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'])
-
-        query = """
-        SELECT DISTINCT %(tag_columns)s%(count_sql)s
-        FROM
-            %(tag)s
-            INNER JOIN %(tagged_item)s
-                ON %(tag)s.id = %(tagged_item)s.tag_id
-            INNER JOIN %(model)s
-                ON %(tagged_item)s.object_id = %(model_pk)s
-            %%s
-        WHERE %(tagged_item)s.content_type_id = %(content_type_id)s
-            %%s
-            %(extra_where)s
-        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),
-            'ordering': ', '.join(qn(field) for field in self.model._meta.ordering),
-            'tag_columns': tag_columns,
-            'count_sql': counts and (', COUNT(%s)' % model_pk) or '',
-            'tagged_item': qn(self.intermediary_table_model._meta.db_table),
-            'model': model_table,
-            'model_pk': model_pk,
-            'extra_where': extra_where,
-            'content_type_id': ContentType.objects.get_for_model(model).pk,
-        }
-
-        min_count_sql = ''
-        if min_count is not None:
-            min_count_sql = 'HAVING COUNT(%s) >= %%s' % model_pk
-            params.append(min_count)
-
-        cursor = connection.cursor()
-        cursor.execute(query % (extra_joins, extra_criteria, min_count_sql), params)
-        tags = []
-        for row in cursor.fetchall():
-            t = self.model(*row[:len(self.model._meta.fields)])
-            if counts:
-                t.count = row[len(self.model._meta.fields)]
-            tags.append(t)
-        return tags
-
-    def usage_for_model(self, model, counts=False, min_count=None, filters=None, extra=None):
+    def usage_for_model(self, model, counts=False, filters=None):

         """
         Obtain a list of tags associated with instances of the given
         Model class.
         """
         Obtain a list of tags associated with instances of the given
         Model class.


@@ -167,39 +100,20 @@ class TagManager(models.Manager):
         each tag, indicating how many times it has been used against
         the Model class in question.
 
         each tag, indicating how many times it has been used against
         the Model class in question.
 

-        If ``min_count`` is given, only tags which have a ``count``
-        greater than or equal to ``min_count`` will be returned.
-        Passing a value for ``min_count`` implies ``counts=True``.
-

         To limit the tags (and counts, if specified) returned to those
         used by a subset of the Model's instances, pass a dictionary
         of field lookups to be applied to the given Model as the
         ``filters`` argument.
         """
         To limit the tags (and counts, if specified) returned to those
         used by a subset of the Model's instances, pass a dictionary
         of field lookups to be applied to the given Model as the
         ``filters`` argument.
         """

-        if extra is None: extra = {}

         if filters is None: filters = {}
 
         if filters is None: filters = {}
 

-        if not parse_lookup:
-            # post-queryset-refactor (hand off to usage_for_queryset)
-            queryset = model._default_manager.filter()
-            for f in filters.items():
-                queryset.query.add_filter(f)
-            usage = self.usage_for_queryset(queryset, counts, min_count, extra)
-        else:
-            # pre-queryset-refactor
-            extra_joins = ''
-            extra_criteria = ''
-            params = []
-            if len(filters) > 0:
-                joins, where, params = parse_lookup(filters.items(), model._meta)
-                extra_joins = ' '.join(['%s %s AS %s ON %s' % (join_type, table, alias, condition)
-                                        for (alias, (table, join_type, condition)) in joins.items()])
-                extra_criteria = 'AND %s' % (' AND '.join(where))
-            usage = self._get_usage(model, counts, min_count, extra_joins, extra_criteria, params, extra)
-
+        queryset = model._default_manager.filter()
+        for f in filters.items():
+            queryset.query.add_filter(f)
+        usage = self.usage_for_queryset(queryset, counts)

         return usage
 
         return usage
 

-    def usage_for_queryset(self, queryset, counts=False, min_count=None, extra=None):
+    def usage_for_queryset(self, queryset, counts=False):

         """
         Obtain a list of tags associated with instances of a model
         contained in the given queryset.
         """
         Obtain a list of tags associated with instances of a model
         contained in the given queryset.


@@ -207,33 +121,18 @@ class TagManager(models.Manager):
         If ``counts`` is True, a ``count`` attribute will be added to
         each tag, indicating how many times it has been used against
         the Model class in question.
         If ``counts`` is True, a ``count`` attribute will be added to
         each tag, indicating how many times it has been used against
         the Model class in question.

-
-        If ``min_count`` is given, only tags which have a ``count``
-        greater than or equal to ``min_count`` will be returned.
-        Passing a value for ``min_count`` implies ``counts=True``.

         """
         """

-        if parse_lookup:
-            raise AttributeError("'TagManager.usage_for_queryset' is not compatible with pre-queryset-refactor versions of Django.")
-
-        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
+        usage = self.model._default_manager.filter(
+            items__content_type=ContentType.objects.get_for_model(queryset.model),
+            items__object_id__in=queryset

             )
             )

+        if counts:
+            usage = usage.annotate(count=models.Count('id'))

         else:
         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:
-            extra_criteria = ''
-        return self._get_usage(queryset.model, counts, min_count, extra_joins, extra_criteria, params, extra)
+            usage = usage.distinct()
+        return usage

 
 

-    def related_for_model(self, tags, model, counts=False, min_count=None, extra=None):
+    def related_for_model(self, tags, model, counts=False):

         """
         Obtain a list of tags related to a given list of tags - that
         is, other tags used by items which have all the given tags.
         """
         Obtain a list of tags related to a given list of tags - that
         is, other tags used by items which have all the given tags.


@@ -241,90 +140,14 @@ class TagManager(models.Manager):
         If ``counts`` is True, a ``count`` attribute will be added to
         each tag, indicating the number of items which have it in
         addition to the given list of tags.
         If ``counts`` is True, a ``count`` attribute will be added to
         each tag, indicating the number of items which have it in
         addition to the given list of tags.

-
-        If ``min_count`` is given, only tags which have a ``count``
-        greater than or equal to ``min_count`` will be returned.
-        Passing a value for ``min_count`` implies ``counts=True``.

         """
         """

-        if min_count is not None: counts = True
-        tags = self.model.get_tag_list(tags)
-        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'])
-
-        # 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
-        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""" % {
-            'tag': qn(self.model._meta.db_table),
-            'ordering': ', '.join(qn(field) for field in self.model._meta.ordering),
-            'tag_columns': tag_columns,
-            'count_sql': counts and ', COUNT(%s.object_id)' % tagged_item_table or '',
-            'tagged_item': tagged_item_table,
-            'content_type_id': ContentType.objects.get_for_model(model).pk,
-            'tag_id_placeholders': ','.join(['%s'] * tag_count),
-            'extra_where': extra_where,
-            'tag_count': tag_count,
-            'min_count_sql': min_count is not None and ('HAVING COUNT(%s.object_id) >= %%s' % tagged_item_table) or '',
-        }
-
-        params = [tag.pk for tag in tags] * 2
-        if min_count is not None:
-            params.append(min_count)
-
-        cursor = connection.cursor()
-        cursor.execute(query, params)
-        related = []
-        for row in cursor.fetchall():
-            tag = self.model(*row[:len(self.model._meta.fields)])
-            if counts is True:
-                tag.count = row[len(self.model._meta.fields)]
-            related.append(tag)
-        return related
-
-    def _get_tag_columns(self):
-        tag_table = qn(self.model._meta.db_table)
-        return ', '.join('%s.%s' % (tag_table, qn(field.column)) for field in self.model._meta.fields)
+        objs = self.model.intermediary_table_model.objects.get_by_model(model, tags)
+        qs = self.usage_for_queryset(objs, counts)
+        qs = qs.exclude(pk__in=[tag.pk for tag in tags])
+        return qs

 
 
 class TaggedItemManager(models.Manager):
 
 
 class TaggedItemManager(models.Manager):

-    """
-    FIXME There's currently no way to get the ``GROUP BY`` and ``HAVING``
-          SQL clauses required by many of this manager's methods into
-          Django's ORM.
-
-          For now, we manually execute a query to retrieve the PKs of
-          objects we're interested in, then use the ORM's ``__in``
-          lookup to return a ``QuerySet``.
-
-          Once the queryset-refactor branch lands in trunk, this can be
-          tidied up significantly.
-    """

     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


@@ -334,176 +157,44 @@ class TaggedItemManager(models.Manager):
         Create a ``QuerySet`` containing instances of the specified
         model associated with a given tag or list of tags.
         """
         Create a ``QuerySet`` containing instances of the specified
         model associated with a given tag or list of tags.
         """

+        queryset, model = get_queryset_and_model(queryset_or_model)

         tags = self.tag_model.get_tag_list(tags)
         tag_count = len(tags)
         tags = self.tag_model.get_tag_list(tags)
         tag_count = len(tags)

-        if tag_count == 0:
+        if not tag_count:

             # No existing tags were given
             # No existing tags were given

-            queryset, model = get_queryset_and_model(queryset_or_model)
-            return model._default_manager.none()
+            return queryset

         elif tag_count == 1:
             # Optimisation for single tag - fall through to the simpler
             # query below.
         elif tag_count == 1:
             # Optimisation for single tag - fall through to the simpler
             # query below.

-            tag = tags[0]
-        else:
-            return self.get_intersection_by_model(queryset_or_model, tags)
+            return queryset.filter(tag_relations__tag=tags[0])

 
 

-        queryset, model = get_queryset_and_model(queryset_or_model)
-        content_type = ContentType.objects.get_for_model(model)
-        opts = self.model._meta
-        tagged_item_table = qn(opts.db_table)
-        return queryset.extra(
-            tables=[opts.db_table],
-            where=[
-                '%s.content_type_id = %%s' % tagged_item_table,
-                '%s.tag_id = %%s' % tagged_item_table,
-                '%s.%s = %s.object_id' % (qn(model._meta.db_table),
-                                          qn(model._meta.pk.column),
-                                          tagged_item_table)
-            ],
-            params=[content_type.pk, tag.pk],
-        )
-
-    def get_intersection_by_model(self, queryset_or_model, tags):
-        """
-        Create a ``QuerySet`` containing instances of the specified
-        model associated with *all* of the given list of tags.
-        """
-        tags = self.tag_model.get_tag_list(tags)
-        tag_count = len(tags)
-        queryset, model = get_queryset_and_model(queryset_or_model)
-
-        if not tag_count:
-            return model._default_manager.none()
-
-        model_table = qn(model._meta.db_table)
-        # This query selects the ids of all objects which have all the
-        # given tags.
-        query = """
-        SELECT %(model_pk)s
-        FROM %(model)s, %(tagged_item)s
-        WHERE %(tagged_item)s.content_type_id = %(content_type_id)s
-          AND %(tagged_item)s.tag_id IN (%(tag_id_placeholders)s)
-          AND %(model_pk)s = %(tagged_item)s.object_id
-        GROUP BY %(model_pk)s
-        HAVING COUNT(%(model_pk)s) = %(tag_count)s""" % {
-            'model_pk': '%s.%s' % (model_table, qn(model._meta.pk.column)),
-            'model': model_table,
-            'tagged_item': qn(self.model._meta.db_table),
-            'content_type_id': ContentType.objects.get_for_model(model).pk,
-            'tag_id_placeholders': ','.join(['%s'] * tag_count),
-            'tag_count': tag_count,
-        }
-
-        cursor = connection.cursor()
-        cursor.execute(query, [tag.pk for tag in tags])
-        object_ids = [row[0] for row in cursor.fetchall()]
-        if len(object_ids) > 0:
-            return queryset.filter(pk__in=object_ids)
-        else:
-            return model._default_manager.none()
+        # TODO: presumes reverse generic relation
+        return queryset.filter(tag_relations__tag__in=tags
+            ).annotate(count=models.Count('pk')).filter(count=len(tags))

 
     def get_union_by_model(self, queryset_or_model, tags):
         """
         Create a ``QuerySet`` containing instances of the specified
         model associated with *any* of the given list of tags.
         """
 
     def get_union_by_model(self, queryset_or_model, tags):
         """
         Create a ``QuerySet`` containing instances of the specified
         model associated with *any* of the given list of tags.
         """

-        tags = self.tag_model.get_tag_list(tags)
-        tag_count = len(tags)

         queryset, model = get_queryset_and_model(queryset_or_model)
         queryset, model = get_queryset_and_model(queryset_or_model)

+        tags = self.tag_model.get_tag_list(tags)
+        if not tags:
+            return queryset
+        # TODO: presumes reverse generic relation
+        return queryset.filter(tag_relations__tag__in=tags)

 
 

-        if not tag_count:
-            return model._default_manager.none()
-
-        model_table = qn(model._meta.db_table)
-        # This query selects the ids of all objects which have any of
-        # the given tags.
-        query = """
-        SELECT %(model_pk)s
-        FROM %(model)s, %(tagged_item)s
-        WHERE %(tagged_item)s.content_type_id = %(content_type_id)s
-          AND %(tagged_item)s.tag_id IN (%(tag_id_placeholders)s)
-          AND %(model_pk)s = %(tagged_item)s.object_id
-        GROUP BY %(model_pk)s""" % {
-            'model_pk': '%s.%s' % (model_table, qn(model._meta.pk.column)),
-            'model': model_table,
-            'tagged_item': qn(self.model._meta.db_table),
-            'content_type_id': ContentType.objects.get_for_model(model).pk,
-            'tag_id_placeholders': ','.join(['%s'] * tag_count),
-        }
-
-        cursor = connection.cursor()
-        cursor.execute(query, [tag.pk for tag in tags])
-        object_ids = [row[0] for row in cursor.fetchall()]
-        if len(object_ids) > 0:
-            return queryset.filter(pk__in=object_ids)
-        else:
-            return model._default_manager.none()
-
-    def get_related(self, obj, queryset_or_model, num=None, ignore_by_tag=None):
+    def get_related(self, obj, queryset_or_model):

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

-
-        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)
         """
         queryset, model = get_queryset_and_model(queryset_or_model)

-        model_table = qn(model._meta.db_table)
-        content_type = ContentType.objects.get_for_model(obj)
-        related_content_type = ContentType.objects.get_for_model(model)
-        query = """
-        SELECT %(model_pk)s, COUNT(related_tagged_item.object_id) AS %(count)s
-        FROM %(model)s, %(tagged_item)s, %(tag)s, %(tagged_item)s related_tagged_item
-        WHERE %(tagged_item)s.object_id = %%s
-          AND %(tagged_item)s.content_type_id = %(content_type_id)s
-          AND %(tag)s.id = %(tagged_item)s.tag_id
-          AND related_tagged_item.content_type_id = %(related_content_type_id)s
-          AND related_tagged_item.tag_id = %(tagged_item)s.tag_id
-          AND %(model_pk)s = related_tagged_item.object_id"""
-        if content_type.pk == related_content_type.pk:
-            # Exclude the given instance itself if determining related
-            # 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
-        %(limit_offset)s"""
-        query = query % {
-            'model_pk': '%s.%s' % (model_table, qn(model._meta.pk.column)),
-            'count': qn('count'),
-            'model': model_table,
-            'tagged_item': qn(self.model._meta.db_table),
-            'tag': qn(self.model._meta.get_field('tag').rel.to._meta.db_table),
-            '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.execute(query, [obj.pk])
-        object_ids = [row[0] for row in cursor.fetchall()]
-        if len(object_ids) > 0:
-            # Use in_bulk here instead of an id__in lookup, because id__in would
-            # clobber the ordering.
-            object_dict = queryset.in_bulk(object_ids)
-            return [object_dict[object_id] for object_id in object_ids \
-                    if object_id in object_dict]
-        else:
-            return []
+        # TODO: presumes reverse generic relation.
+        # Do we know it's 'tags'?
+        return queryset.filter(tag_relations__tag__in=obj.tags).annotate(
+            count=models.Count('pk')).order_by('-count').exclude(obj=obj.pk)

 
 
 ##########
 
 
 ##########

diff --git a/apps/newtagging/views.py b/apps/newtagging/views.py
index dee8e18..867686d 100644 (file)
--- a/apps/newtagging/views.py
+++ b/apps/newtagging/views.py
@@ -36,7 +36,7 @@ def tagged_object_list(request, queryset_or_model=None, tag_model=None, tags=Non
     tag_instances = tag_model.get_tag_list(tags)
     if tag_instances is None:
         raise Http404(_('No tags found matching "%s".') % tags)
     tag_instances = tag_model.get_tag_list(tags)
     if tag_instances is None:
         raise Http404(_('No tags found matching "%s".') % tags)

-    queryset = tag_model.intermediary_table_model.objects.get_intersection_by_model(queryset_or_model, tag_instances)
+    queryset = tag_model.intermediary_table_model.objects.get_by_model(queryset_or_model, tag_instances)

     if not kwargs.has_key('extra_context'):
         kwargs['extra_context'] = {}
     kwargs['extra_context']['tags'] = tag_instances
     if not kwargs.has_key('extra_context'):
         kwargs['extra_context'] = {}
     kwargs['extra_context']['tags'] = tag_instances