mygpo/web/heatmap.py

   1 #
   2 # This file is part of my.gpodder.org.
   3 #
   4 # my.gpodder.org is free software: you can redistribute it and/or modify it
   5 # under the terms of the GNU Affero General Public License as published by
   6 # the Free Software Foundation, either version 3 of the License, or (at your
   7 # option) any later version.
   8 #
   9 # my.gpodder.org is distributed in the hope that it will be useful, but
  10 # WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
  11 # or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Affero General Public
  12 # License for more details.
  13 #
  14 # You should have received a copy of the GNU Affero General Public License
  15 # along with my.gpodder.org. If not, see <http://www.gnu.org/licenses/>.
  16 #
  17
  18 from functools import wraps
  19
  20 from mygpo.db.couchdb.episode_state import get_heatmap
  21
  22
  23 class EpisodeHeatmap(object):
  24     """ Information about how often certain parts of Episodes are played """
  25
  26     def __init__(self, podcast_id, episode_id=None, user_id=None,
  27                  duration=None):
  28         """ Initialize a new Episode heatmap
  29
  30         EpisodeHeatmap(podcast_id, [episode_id, [user_id]]) """
  31
  32         self.podcast_id = podcast_id
  33
  34         if episode_id is not None and podcast_id is None:
  35             raise ValueError(
  36                 'episode_id can only be used if podcast_id is not None')
  37
  38         self.episode_id = episode_id
  39
  40         if user_id is not None and episode_id is None:
  41             raise ValueError(
  42                 'user_id can only be used if episode_id is not None')
  43
  44         self.user_id = user_id
  45         self.duration = duration
  46         self.heatmap = None
  47         self.borders = None
  48
  49     def _query(self):
  50         """ Queries the database and stores the heatmap and its borders """
  51
  52         self.heatmap, self.borders = get_heatmap(
  53             self.podcast_id, self.episode_id, self.user_id)
  54
  55         if self.borders and self.heatmap:
  56             # heatmap info doesn't reach until the end of the episode
  57             # so we extend it with 0 listeners
  58             if self.duration > self.borders[-1]:
  59                 self.heatmap.append(0)
  60                 self.borders.append(self.duration)
  61
  62     def query_if_required():
  63         """ If required, queries the database before calling the function """
  64
  65         def decorator(f):
  66             @wraps(f)
  67             def tmp(self, *args, **kwargs):
  68                 if None in (self.heatmap, self.borders):
  69                     self._query()
  70
  71                 return f(self, *args, **kwargs)
  72             return tmp
  73         return decorator
  74
  75     @property
  76     @query_if_required()
  77     def max_plays(self):
  78         """ Returns the highest number of plays of all sections """
  79
  80         return max(self.heatmap)
  81
  82     @property
  83     @query_if_required()
  84     def sections(self):
  85         """ Returns an iterator that emits (from, to, play-counts) tuples
  86
  87         Each tuple represents one part in the heatmap with a distinct
  88         play-count. from and to indicate the range of section in seconds."""
  89
  90         for i in range(len(self.heatmap)):
  91             yield (self.borders[i], self.borders[i+1], self.heatmap[i])
  92
  93     @query_if_required()
  94     def __nonzero__(self):
  95         return any(self.heatmap)