def _search_and_cache(tag_ids):
"""
Arguments:
tag_ids == list of Tag IDs
Note:
To make this method more efficient, tags should be sorted by some
of its attributes (e.g. by id itself).
"""
key = _normal_search_key(tag_ids)
try:
return SearchCache.objects.get(key=key)
except:
cache = SearchCache(key=key)
cache.save()
tags = Tag.objects.filter(id__in=tag_ids)
cache.tags.set(*tags) # Do not use set_tags() here.
cache_content_type = ContentType.objects.get_for_model(SearchCache)
tag_id = tag_ids[-1]
if len(tag_ids) > 1:
recursion = _search_and_cache(tag_ids[:-1])
query = 'INSERT INTO search_searchcacheelement (object_id, content_type_id, cache_id)' \
' SELECT A.object_id, A.content_type_id, %d FROM search_searchcacheelement AS A' \
' INNER JOIN tags_taggeditem AS B ON (A.object_id = B.object_id AND A.content_type_id = B.content_type_id)' \
' WHERE A.cache_id=%d AND B.tag_id=%d;' \
% (cache.id, recursion.id, tag_id)
else:
# search shouldn't include itself
query = 'INSERT INTO search_searchcacheelement (object_id, content_type_id, cache_id)' \
' SELECT A.object_id, A.content_type_id, %d FROM tags_taggeditem AS A' \
' WHERE A.tag_id=%d AND A.content_type_id != %d;' \
% (cache.id, tag_id, cache_content_type.id)
cursor = connection.cursor()
cursor.execute(query)
transaction.commit_unless_managed()
return cache
def reverse_search(input):
"""
Find all objects whose tags are a subset of given tags.
Returns SearchCache object if any (existing) tag given, otherwise None.
Example:
reverse_search(['imo', '1997'])
--> SearchCache pointing to:
--> Folder with filter tag 'imo'
--> Folder with filter tag 'imo', '1997'
(...)
Examples of non matching objects:
--> Folder with filter tag 'shortlist', '1997'
--> Task with tags 'imo', '1997', 'geo'
"""
input = split_tags(input)
if not input:
return None # if no tag given, don't just return all objects
tags = get_available_tags(input)
if len(tags) != len(input):
return None
tag_ids = [x.id for x in tags]
key = _reverse_search_key(tag_ids)
try:
return SearchCache.objects.get(key=key)
except SearchCache.DoesNotExist:
pass
# Create cache object.
cache = SearchCache(key=key)
cache.save()
cache.tags.set(*tags) # Do not use set_tags here.
# Generate SQL query
cache_content_type = ContentType.objects.get_for_model(SearchCache)
tag_ids = [x.id for x in tags]
query = 'SELECT DISTINCT A.object_id, A.content_type_id, A.tag_id FROM tags_taggeditem A' \
' INNER JOIN tags_taggeditem B' \
' ON (A.object_id = B.object_id AND A.content_type_id = B.content_type_id)' \
' WHERE B.tag_id IN (%s) AND B.content_type_id != %d' \
% (','.join([str(id) for id in tag_ids]), cache_content_type.id)
# Manually fetch.
cursor = connection.cursor()
cursor.execute(query)
tagged_items = cursor.fetchall()
# Generate and save search result.
objects = defaultdict(set)
for object_id, content_type_id, tag_id in tagged_items:
# Seperate tagged items by objects (get tags for each object)
objects[(object_id, content_type_id)].add(tag_id)
ids_set = set(tag_ids)
# Filter only those objects whose tags are subset of the given set of tags
SearchCacheElement.objects.bulk_create(
SearchCacheElement(object_id=key[0], content_type_id=key[1], cache=cache)
for key, obj_tags in objects.iteritems()
if obj_tags.issubset(ids_set)
)
return cache
