mygpo/api/backend.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 collections import defaultdict
  19 from functools import partial
  20
  21 from mygpo.core.models import Podcast, Episode
  22 from mygpo.users.models import EpisodeUserState, Device, DeviceDoesNotExist, \
  23          PodcastUserState
  24 from mygpo.decorators import repeat_on_conflict
  25 from mygpo.couch import bulk_save_retry
  26 from mygpo.json import json
  27 from mygpo.users.settings import STORE_UA
  28 from mygpo.db.couchdb.podcast import podcast_for_url, random_podcasts
  29 from mygpo.db.couchdb.podcast_state import podcast_state_for_user_podcast
  30
  31
  32 def get_random_picks(languages=None):
  33     """ Returns random podcasts for the given language """
  34
  35     languages = languages or ['']
  36
  37     # get one iterator for each language
  38     rand_iters = [random_podcasts(lang) for lang in languages]
  39
  40     # cycle through them, removing those that don't yield any more results
  41     while rand_iters:
  42         rand_iter = rand_iters.pop(0)
  43
  44         try:
  45             podcast = next(rand_iter)
  46             rand_iters.append(rand_iter)
  47             yield podcast
  48
  49         except StopIteration:
  50             # don't re-add rand_iter
  51             pass
  52
  53
  54
  55 def get_device(user, uid, user_agent, undelete=True):
  56     """
  57     Loads or creates the device indicated by user, uid.
  58
  59     If the device has been deleted and undelete=True, it is undeleted.
  60     """
  61
  62     store_ua = user.get_wksetting(STORE_UA)
  63
  64     @repeat_on_conflict(['user'])
  65     def _get(user, uid, undelete):
  66
  67         save = False
  68
  69         try:
  70             device = user.get_device_by_uid(uid, only_active=False)
  71
  72         except DeviceDoesNotExist:
  73             device = Device(uid=uid)
  74             user.devices.append(device)
  75             save = True
  76
  77         if device.deleted and undelete:
  78             device.deleted = False
  79             user.set_device(device)
  80             save = True
  81
  82         if store_ua and user_agent and \
  83                 getattr(device, 'user_agent', None) != user_agent:
  84             device.user_agent = user_agent
  85             user.set_device(device)
  86             save = True
  87
  88         if save:
  89             user.save()
  90
  91         return device
  92
  93     return _get(user=user, uid=uid, undelete=undelete)
  94
  95
  96 class BulkSubscribe(object):
  97     """ Performs bulk subscribe/unsubscribe operations """
  98
  99     def __init__(self, user, device, podcasts = {}, actions=None):
 100         self.user = user
 101         self.device = device
 102         self.podcasts = podcasts
 103         self.actions = actions or []
 104
 105         self.operations = {
 106             'subscribe':   partial(self._subscribe,   device=device),
 107             'unsubscribe': partial(self._unsubscribe, device=device),
 108         }
 109
 110
 111     def execute(self):
 112         """ Executes all added actions in bulk """
 113         obj_funs = map(self._get_obj_fun, self.actions)
 114         bulk_save_retry(obj_funs)
 115
 116         # prepare for another run
 117         self.actions = []
 118
 119
 120     def add_action(self, url, op):
 121         """ Adds a new (un)subscribe action
 122
 123         url is the podcast url to subscribe to / unsubscribe from
 124         op is either "subscribe" or "unsubscribe" """
 125         self.actions.append( (url, op) )
 126
 127
 128     def _get_obj_fun(self, action):
 129         url, op = action
 130
 131         podcast = self.podcasts.get(url,
 132                 podcast_for_url(url, create=True))
 133
 134         state = podcast_state_for_user_podcast(self.user, podcast)
 135
 136         fun = self.operations[op]
 137         return (state, fun)
 138
 139
 140
 141     def _subscribe(self, state, device):
 142         state.subscribe(device)
 143         return state
 144
 145     def _unsubscribe(self, state, device):
 146         state.unsubscribe(device)
 147         return state