class Poller(object):
def __init__(self):
rospy.init_node('poller_node')
self.rate = rospy.Rate(3) # 3hz
self.extractBasestationFromParams()
self.createCommunicators()
self.request_list = OrderedSet([])
def createCommunicators(self):
self.client = Client(10019)
self.measurements_publisher = rospy.Publisher('measurements', MeasurementList, queue_size=10)
self.request_subscriber = rospy.Subscriber("measurements_request", String, self.pushbackRequest)
def extractBasestationFromParams(self):
stations = rospy.get_param("/poller_node/basestations")
self.storeBasestation(stations)
def storeBasestation(self, stations):
self.basestations = []
for station in stations:
self.basestations.append(Basestation(station[0], float(station[1]), float(station[2])))
def pushbackRequest(self, msg):
self.request_list.add(msg.data)
def measurementsLoop(self):
while not rospy.is_shutdown():
while not self.request_list.isEmpty():
station_address = self.request_list.pop()
self.serveRequest(station_address)
self.rate.sleep()
def pollStation(self, station_address):
return self.client.pollBasestation(station_address)
def serveRequest(self, station_address):
try:
data = self.pollStation(station_address)
if containsMeasurements(data):
self.publishMeasuements(extractJson(data), station_address)
except socket.error:
pass
def publishMeasuements(self, measurs, station):
msg = MeasurementList()
for el in measurs:
msg.data.append(self.generateMeasurement(el))
msg.basestation = station
msg.header.stamp = rospy.Time.now()
self.measurements_publisher.publish(msg)
def generateMeasurement(self, element):
tmp = Measurement()
tmp.tag = element['id_tag'].encode('utf-8')
tmp.measurement = int(element['rssid'])
return tmp
