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