mygpo/pubsub/__init__.py

   1 # -*- coding: utf-8 -*-
   2 #
   3 # PubSubHubbub subscriber mygpo
   4 #
   5 #
   6
   7 import urllib
   8 import urllib2
   9 import logging
  10
  11 from django.core.urlresolvers import reverse
  12
  13 from mygpo.utils import random_token
  14 from mygpo.pubsub.models import HubSubscription, SubscriptionError
  15
  16 logger = logging.getLogger(__name__)
  17
  18
  19 def subscribe(podcast, feedurl, huburl, base_url, mode='subscribe'):
  20     """ Subscribe to the feed at a Hub """
  21
  22     logger.info('subscribing for {feed} at {hub}'.format(feed=feedurl,
  23                                                          hub=huburl))
  24     verify = 'sync'
  25
  26     token_max_len = HubSubscription._meta.get_field('verify_token').max_length
  27     subscription, created = HubSubscription.objects.get_or_create(
  28         topic_url=feedurl,
  29         defaults={
  30             'verify_token': random_token(token_max_len),
  31             'mode': '',
  32             'podcast': podcast,
  33         }
  34     )
  35
  36     if subscription.mode == mode:
  37         if subscription.verified:
  38             logger.info('subscription already exists')
  39             return
  40
  41     else:
  42         logger.info('subscription exists but has wrong mode: ' +
  43                     'old: %(oldmode)s, new: %(newmode)s. Overwriting.' %
  44                     dict(oldmode=subscription.mode, newmode=mode))
  45
  46     subscription.topic_url = feedurl
  47     subscription.mode = mode
  48     subscription.save()
  49
  50     data = {
  51         "hub.callback":     callback_url(feedurl, base_url),
  52         "hub.mode":         mode,
  53         "hub.topic":        feedurl,
  54         "hub.verify":       verify,
  55         "hub.verify_token": subscription.verify_token,
  56     }
  57
  58     data = urllib.urlencode(data.items())
  59     logger.debug('sending request: %s' % repr(data))
  60
  61     resp = None
  62
  63     try:
  64         resp = urllib2.urlopen(huburl, data)
  65
  66     except urllib2.HTTPError, e:
  67         if e.code != 204:  # we actually expect a 204 return code
  68             msg = 'Could not send subscription to Hub: HTTP Error %d: %s' % \
  69                 (e.code, e.reason)
  70             logger.warn(msg)
  71             raise SubscriptionError(msg)
  72
  73     except Exception, e:
  74         msg = 'Could not send subscription to Hub: %s' % repr(e)
  75         logger.warn(msg)
  76         raise SubscriptionError(msg)
  77
  78     if resp:
  79         status = resp.code
  80         if status != 204:
  81             logger.warn('received incorrect status %d' % status)
  82             raise SubscriptionError('Subscription has not been accepted by '
  83                                     'the Hub')
  84
  85
  86 def callback_url(feedurl, base_url):
  87     callback = reverse('pubsub-subscribe')
  88     param = urllib.urlencode([('url', feedurl)])
  89     return '{base}{callback}?{param}'.format(base=base_url, callback=callback,
  90                                              param=param)