scales.PmfStat('setAttr'))

    zf = ZmqFactory()

    addr = 'tcp://*:%s' % port

    log.info('creating zmq endpoint at %r', addr)

    e = ZmqEndpoint('bind', addr)

    s = ZmqPullConnection(zf, e)

    def onPull(message):

        with stats.setAttr.time():

            # todo: new compressed protocol where you send all URIs up

            # front and then use small ints to refer to devices and

            # attributes in subsequent requests.

            client, clientSession, settings, sendTime = parseJsonMessage(message[0])

            collector.setAttrs(client, clientSession, settings, sendTime)

    s.onPull = onPull

class WebListeners(object):

    def __init__(self):

        self.clients = []

        self.pendingMessageForDev = {} # dev: (attrs, outputmap)

        self.lastFlush = 0

    def addClient(self, client):

        self.clients.append([client, {}]) # seen = {dev: attrs}

    def delClient(self, client):

        self.clients = [[c, t] for c, t in self.clients if c != client]

        log.info('delClient %s, %s left', client, len(self.clients))

    def outputAttrsSet(self, dev, attrs, outputMap):

        """called often- don't be slow"""

        self.pendingMessageForDev[dev] = (attrs, outputMap)

        self._flush()

    def _flush(self):

        now = time.time()

        if now < self.lastFlush + .05 or not self.clients:

            return

        self.lastFlush = now

        while self.pendingMessageForDev:

            dev, (attrs, outputMap) = self.pendingMessageForDev.popitem()

            msg = None # lazy, since makeMsg is slow

            # this omits repeats, but can still send many

            # messages/sec. Not sure if piling up messages for the browser