def _sub_channel(self, channel):
"""
Subscribe to a channel using a defer.
This call will queue channel subscriptions.
@param channel: the desired channel.
"""
if self._subscribed['subscribed'].get(channel):
# already subcribed
return defer.succeed(True)
if self._subscribed['running']:
# call it later, queue it
d = self._subscribed['defer']
d.addCallback(self._get_sub_channel_cb(channel))
return d
def set_subscribed(*args):
'''
Called when channel was subscribed.
'''
self._subscribed['running'] = False
self._subscribed['subscribed'][channel] = True
return True
self._subscribed['running'] = True
self.redis.subscribe(channel)
d = defer.Deferred()
self._subscribed['defer'] = d
self._subscribed['running_for'] = channel
return d.addCallback(set_subscribed)
def register_handler(self, evt, handler):
"""
Register a function to respond to feed events.
Event types/handler params:
- create handler(feedname)
- newfeed handler(feedname)
- delete handler(feedname)
- delfeed handler(feedname)
- feed.publish:[feed] handler(id, item)
- feed.retract:[feed] handler(id)
- feed.edit:[feed] handler(id, item)
@param evt: The name of the feed event.
@param handler: The function for handling the event.
"""
channel = self._evt2channel(evt)
if not channel:
return defer.succeed(None)
def _register_callback(*args):
"""
Called when channel was subscribed.
"""
id_ = self._handlers['id_gen'].next()
# store map id -> channel
self._handlers['id2channel'][id_] = channel
handlers = self._handlers['channel_handlers'].get(channel)
if not handlers:
handlers = self._handlers['channel_handlers'][channel] = OrderedDict()
# store handler
handlers[id_] = handler
return id_
return self._sub_channel(channel).addCallback(_register_callback)
