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