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Diffstat (limited to 'tagging/.svn/text-base/models.py.svn-base')
| -rw-r--r-- | tagging/.svn/text-base/models.py.svn-base | 502 |
1 files changed, 0 insertions, 502 deletions
diff --git a/tagging/.svn/text-base/models.py.svn-base b/tagging/.svn/text-base/models.py.svn-base deleted file mode 100644 index 7463ddb..0000000 --- a/tagging/.svn/text-base/models.py.svn-base +++ /dev/null @@ -1,502 +0,0 @@ -""" -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.db.models.query import QuerySet -from django.utils.translation import ugettext_lazy as _ - -from tagging import settings -from tagging.utils import calculate_cloud, get_tag_list, get_queryset_and_model, parse_tag_input -from tagging.utils import LOGARITHMIC -from tagging.validators import isTag - -qn = connection.ops.quote_name - -try: - from django.db.models.query import parse_lookup -except ImportError: - parse_lookup = None - -############ -# Managers # -############ - -class TagManager(models.Manager): - def update_tags(self, obj, tag_names): - """ - Update tags associated with an object. - """ - ctype = ContentType.objects.get_for_model(obj) - current_tags = list(self.filter(items__content_type__pk=ctype.pk, - items__object_id=obj.pk)) - updated_tag_names = parse_tag_input(tag_names) - if settings.FORCE_LOWERCASE_TAGS: - updated_tag_names = [t.lower() for t in updated_tag_names] - - # Remove tags which no longer apply - tags_for_removal = [tag for tag in current_tags \ - if tag.name not in updated_tag_names] - if len(tags_for_removal): - TaggedItem._default_manager.filter(content_type__pk=ctype.pk, - object_id=obj.pk, - tag__in=tags_for_removal).delete() - # Add new tags - current_tag_names = [tag.name for tag in current_tags] - for tag_name in updated_tag_names: - if tag_name not in current_tag_names: - tag, created = self.get_or_create(name=tag_name) - TaggedItem._default_manager.create(tag=tag, object=obj) - - def add_tag(self, obj, tag_name): - """ - Associates the given object with a tag. - """ - tag_names = parse_tag_input(tag_name) - if not len(tag_names): - raise AttributeError(_('No tags were given: "%s".') % tag_name) - if len(tag_names) > 1: - raise AttributeError(_('Multiple tags were given: "%s".') % tag_name) - tag_name = tag_names[0] - if settings.FORCE_LOWERCASE_TAGS: - tag_name = tag_name.lower() - tag, created = self.get_or_create(name=tag_name) - ctype = ContentType.objects.get_for_model(obj) - TaggedItem._default_manager.get_or_create( - tag=tag, content_type=ctype, object_id=obj.pk) - - def get_for_object(self, obj): - """ - Create a queryset matching all tags associated with the given - object. - """ - 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): - """ - 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)) - query = """ - SELECT DISTINCT %(tag)s.id, %(tag)s.name%(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 - GROUP BY %(tag)s.id, %(tag)s.name - %%s - ORDER BY %(tag)s.name ASC""" % { - 'tag': qn(self.model._meta.db_table), - 'count_sql': counts and (', COUNT(%s)' % model_pk) or '', - 'tagged_item': qn(TaggedItem._meta.db_table), - 'model': model_table, - 'model_pk': model_pk, - '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[:2]) - if counts: - t.count = row[2] - tags.append(t) - return tags - - def usage_for_model(self, model, counts=False, min_count=None, filters=None): - """ - Obtain a list of tags associated with instances of the given - Model class. - - 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``. - - 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 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) - 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) - - return usage - - def usage_for_queryset(self, queryset, counts=False, min_count=None): - """ - Obtain a list of tags associated with instances of a model - contained in the given queryset. - - 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.") - - 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) - - def related_for_model(self, tags, model, counts=False, min_count=None): - """ - 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. - - 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 = get_tag_list(tags) - tag_count = len(tags) - tagged_item_table = qn(TaggedItem._meta.db_table) - query = """ - SELECT %(tag)s.id, %(tag)s.name%(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) - GROUP BY %(tag)s.id, %(tag)s.name - %(min_count_sql)s - ORDER BY %(tag)s.name ASC""" % { - 'tag': qn(self.model._meta.db_table), - '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), - '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[:2]) - if counts is True: - tag.count = row[2] - related.append(tag) - return related - - def cloud_for_model(self, model, steps=4, distribution=LOGARITHMIC, - filters=None, min_count=None): - """ - Obtain a list of tags associated with instances of the given - Model, giving each tag a ``count`` attribute indicating how - many times it has been used and a ``font_size`` attribute for - use in displaying a tag cloud. - - ``steps`` defines the range of font sizes - ``font_size`` will - be an integer between 1 and ``steps`` (inclusive). - - ``distribution`` defines the type of font size distribution - algorithm which will be used - logarithmic or linear. It must - be either ``tagging.utils.LOGARITHMIC`` or - ``tagging.utils.LINEAR``. - - To limit the tags displayed in the cloud to those associated - with 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 displayed in the cloud to those with a - ``count`` greater than or equal to ``min_count``, pass a value - for the ``min_count`` argument. - """ - tags = list(self.usage_for_model(model, counts=True, filters=filters, - min_count=min_count)) - return calculate_cloud(tags, steps, distribution) - -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 get_by_model(self, queryset_or_model, tags): - """ - Create a ``QuerySet`` containing instances of the specified - model associated with a given tag or list of tags. - """ - tags = get_tag_list(tags) - tag_count = len(tags) - if tag_count == 0: - # No existing tags were given - queryset, model = get_queryset_and_model(queryset_or_model) - return model._default_manager.none() - 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) - - 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 = 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() - - 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 = 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 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): - """ - 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. - """ - 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""" - 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 '', - } - - 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 [] - -########## -# Models # -########## - -class Tag(models.Model): - """ - A tag. - """ - name = models.CharField(_('name'), max_length=50, unique=True, db_index=True, validator_list=[isTag]) - - objects = TagManager() - - class Meta: - ordering = ('name',) - verbose_name = _('tag') - verbose_name_plural = _('tags') - - class Admin: - pass - - def __unicode__(self): - return self.name - -class TaggedItem(models.Model): - """ - Holds the relationship between a tag and the item being tagged. - """ - tag = models.ForeignKey(Tag, verbose_name=_('tag'), related_name='items') - content_type = models.ForeignKey(ContentType, verbose_name=_('content type')) - object_id = models.PositiveIntegerField(_('object id'), db_index=True) - object = generic.GenericForeignKey('content_type', 'object_id') - - objects = TaggedItemManager() - - class Meta: - # Enforce unique tag association per object - unique_together = (('tag', 'content_type', 'object_id'),) - verbose_name = _('tagged item') - verbose_name_plural = _('tagged items') - - class Admin: - pass - - def __unicode__(self): - return u'%s [%s]' % (self.object, self.tag) |