mygpo/directory/toplist.py

   1 from itertools import product
   2
   3 from datetime import date, timedelta
   4
   5 from django.core.cache import cache
   6
   7 from mygpo.core.models import Episode, Podcast, PodcastGroup
   8 from mygpo.data.mimetype import get_type, CONTENT_TYPES
   9 from mygpo.utils import daterange
  10 from mygpo.db.couchdb.directory import toplist
  11
  12
  13 CACHE_SECONDS = 60*60
  14
  15 class Toplist(object):
  16     """ Base class for Episode and Podcast toplists """
  17
  18     def __init__(self, cls, view, language='', view_args={}):
  19         self.cls       = cls
  20         self.language  = language
  21         self.view      = view
  22         self.view_args = view_args
  23
  24
  25     def _get_query_keys(self):
  26         """ Returns an iterator of query keys that are passed to the view """
  27         return [self.language]
  28
  29
  30     def _query(self, limit):
  31         """ Queries the database and returns the sorted results """
  32
  33         key = self._get_query_keys()
  34         results = self._cache_or_query(limit, key)
  35         results = self._sort(results)
  36         return results[:limit]
  37
  38
  39     def _cache_or_query(self, limit, key):
  40         return toplist(self.cls, self.view, key, limit, **self.view_args)
  41
  42
  43     def _sort(self, results):
  44         return results
  45
  46
  47     def __getitem__(self, key):
  48         if isinstance(key, slice):
  49             start = key.start or 0
  50             length = key.stop - start
  51         else:
  52             start = key
  53             length = 1
  54
  55         return self._query(length)
  56
  57
  58
  59 class EpisodeToplist(Toplist):
  60     """ Retrieves the episode toplist for a certain date """
  61
  62     def __init__(self, language='', startdate=None):
  63         super(EpisodeToplist, self).__init__(Episode,
  64                 'toplist/episodes', language)
  65         self.date = startdate or date.today()
  66
  67
  68     def _sort(self, results):
  69         results.sort(key=lambda episode: episode.listeners, reverse=True)
  70         return results
  71
  72
  73     def _get_query_keys(self):
  74         """ Returns the query keys based on instance variables """
  75
  76         date_str = self.date.strftime('%Y-%m-%d')
  77         return [date_str] + super(EpisodeToplist, self)._get_query_keys()
  78
  79
  80
  81 class PodcastToplist(Toplist):
  82     """ Podcast toplist based on number of subscribers """
  83
  84     def __init__(self, language=''):
  85         super(PodcastToplist, self).__init__(Podcast, 'toplist/podcasts',
  86                 language,
  87                 view_args=dict(classes=[Podcast, PodcastGroup]))
  88
  89
  90     def _sort(self, results):
  91         # sort by subscriber_count and id to ensure same order when subscriber_count is equal
  92         cur  = sorted(results, key=lambda p: (p.subscriber_count(), p.get_id()),      reverse=True)
  93         prev = sorted(results, key=lambda p: (p.prev_subscriber_count(), p.get_id()), reverse=True)
  94
  95         res = dict( (p, n) for n, p in enumerate(cur))
  96
  97         for old, p in enumerate(prev):
  98             new = res.get(p, 0)
  99             res[p] = (new, old)
 100
 101         return [(old+1, p) for p, (new, old) in sorted(res.items(), key=lambda i: i[1][0])]
 102
 103
 104 class TrendingPodcasts(Toplist):
 105     """ Trending podcasts based on current / previous subscribers ratio """
 106
 107     def __init__(self, language=''):
 108         super(TrendingPodcasts, self).__init__(Podcast, 'trending/podcasts',
 109                 language,
 110                 view_args=dict(classes=[Podcast, PodcastGroup]))