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 @repeat_on_conflict(['user'])
  56 def get_device(user, uid, user_agent, undelete=True):
  57     """
  58     Loads or creates the device indicated by user, uid.
  59
  60     If the device has been deleted and undelete=True, it is undeleted.
  61     """
  62
  63     store_ua = user.get_wksetting(STORE_UA)
  64
  65     save = False
  66
  67     try:
  68         device = user.get_device_by_uid(uid, only_active=False)
  69
  70     except DeviceDoesNotExist:
  71         device = Device(uid=uid)
  72         user.devices.append(device)
  73         save = True
  74
  75     if device.deleted and undelete:
  76         device.deleted = False
  77         user.set_device(device)
  78         save = True
  79
  80     if store_ua and user_agent and \
  81             getattr(device, 'user_agent', None) != user_agent:
  82         device.user_agent = user_agent
  83         user.set_device(device)
  84         save = True
  85
  86     if save:
  87         user.save()
  88
  89     return device
  90
  91
  92 class BulkSubscribe(object):
  93     """ Performs bulk subscribe/unsubscribe operations """
  94
  95     def __init__(self, user, device, podcasts = {}, actions=None):
  96         self.user = user
  97         self.device = device
  98         self.podcasts = podcasts
  99         self.actions = actions or []
 100
 101         self.operations = {
 102             'subscribe':   partial(self._subscribe,   device=device),
 103             'unsubscribe': partial(self._unsubscribe, device=device),
 104         }
 105
 106
 107     def execute(self):
 108         """ Executes all added actions in bulk """
 109         obj_funs = map(self._get_obj_fun, self.actions)
 110         bulk_save_retry(obj_funs)
 111
 112         # prepare for another run
 113         self.actions = []
 114
 115
 116     def add_action(self, url, op):
 117         """ Adds a new (un)subscribe action
 118
 119         url is the podcast url to subscribe to / unsubscribe from
 120         op is either "subscribe" or "unsubscribe" """
 121         self.actions.append( (url, op) )
 122
 123
 124     def _get_obj_fun(self, action):
 125         url, op = action
 126
 127         podcast = self.podcasts.get(url,
 128                 podcast_for_url(url, create=True))
 129
 130         state = podcast_state_for_user_podcast(self.user, podcast)
 131
 132         fun = self.operations[op]
 133         return (state, fun)
 134
 135
 136
 137     def _subscribe(self, state, device):
 138         state.subscribe(device)
 139         return state
 140
 141     def _unsubscribe(self, state, device):
 142         state.unsubscribe(device)
 143         return state