mygpo/search/index.py

   1 """ Contains code for searching podcasts
   2
   3 Uses django.contrib.postgres.search for searching. See docs at
   4 https://docs.djangoproject.com/en/1.11/ref/contrib/postgres/search/
   5
   6 """
   7
   8 from django.conf import settings
   9
  10 from mygpo.podcasts.models import Podcast
  11
  12 from django.db.models import F, FloatField, ExpressionWrapper
  13 from django.contrib.postgres.search import SearchQuery, SearchRank
  14 from django.conf import settings
  15
  16 import logging
  17
  18 logger = logging.getLogger(__name__)
  19
  20
  21 SEARCH_CUTOFF = settings.SEARCH_CUTOFF
  22
  23
  24 def search_podcasts(query):
  25     """Search for podcasts according to 'query'"""
  26     if is_query_too_short(query):
  27         logger.debug('Found no podcasts for "{query}". Query is too short', query=query)
  28         return Podcast.objects.none()
  29
  30     logger.debug('Searching for "{query}" podcasts"', query=query)
  31
  32     query = SearchQuery(query)
  33
  34     results = (
  35         Podcast.objects.annotate(rank=SearchRank(F("search_vector"), query))
  36         .annotate(
  37             order=ExpressionWrapper(
  38                 F("rank") * F("subscribers"), output_field=FloatField()
  39             )
  40         )
  41         .filter(rank__gte=SEARCH_CUTOFF)
  42         .order_by("-order")[:100]
  43         .prefetch_related("slugs")
  44     )
  45
  46     logger.debug(
  47         'Found {count} podcasts for "{query}"', count=len(results), query=query
  48     )
  49
  50     return results
  51
  52
  53 def is_query_too_short(query):
  54     return len(query.replace(" ", "")) <= settings.QUERY_LENGTH_CUTOFF