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"""Procedures to initialize the full text search in PostgresQL"""
from django.db import connection
from django.conf import settings as django_settings
from django.utils.translation import get_language
def setup_full_text_search(script_path):
"""using postgresql database connection,
installs the plsql language, if necessary
and runs the stript, whose path is given as an argument
"""
fts_init_query = open(script_path).read()
cursor = connection.cursor()
try:
#test if language exists
cursor.execute("SELECT * FROM pg_language WHERE lanname='plpgsql'")
lang_exists = cursor.fetchone()
if not lang_exists:
cursor.execute("CREATE LANGUAGE plpgsql")
#run the main query
cursor.execute(fts_init_query)
finally:
cursor.close()
def run_full_text_search(query_set, query_text, text_search_vector_name):
"""runs full text search against the query set and
the search text. All words in the query text are
added to the search with the & operator - i.e.
the more terms in search, the narrower it is.
It is also assumed that we ar searching in the same
table as the query set was built against, also
it is assumed that the table has text search vector
stored in the column called with value of`text_search_vector_name`.
"""
table_name = query_set.model._meta.db_table
rank_clause = 'ts_rank(' + table_name + \
'.' + text_search_vector_name + \
', plainto_tsquery(%s))'
where_clause = table_name + '.' + \
text_search_vector_name + \
' @@ plainto_tsquery(%s)'
search_query = '&'.join(query_text.split())#apply "AND" operator
extra_params = (search_query,)
extra_kwargs = {
'select': {'relevance': rank_clause},
'where': [where_clause,],
'params': extra_params,
'select_params': extra_params,
}
if getattr(django_settings, 'ASKBOT_MULTILINGUAL', True):
extra_kwargs['select']['language_code'] = get_language()
return query_set.extra(**extra_kwargs)
def run_thread_search(query_set, query):
"""runs search for full thread content"""
return run_full_text_search(query_set, query, 'text_search_vector');
def run_title_search(query_set, query):
"""runs search for title and tags"""
return run_full_text_search(query_set, query, 'title_search_vector')
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