subscriber.py

# Sample code for CS6381
# Vanderbilt University
# Instructor: Aniruddha Gokhale
#
# Code taken from ZeroMQ examples with additional
# comments or extra statements added to make the code
# more self-explanatory  or tweak it for our purposes
#
# We are executing these samples on a Mininet-emulated environment
#
#   Weather update client
#   Connects SUB socket to tcp://localhost:5556
#   Collects weather updates and finds avg temp in zipcode
import sys
import zmq

class Subscriber:
	"""Implementation of the subscriber"""
	def __init__(self, broker_addr, broker_port, zipcode):
		self.broker = broker_addr
		self.port = broker_port
		self.zipcode = zipcode
		self.socket = zmq.Context().socket(zmq.SUB)
		# Connect to broker
		#context = zmq.Context()
		# Since we are the subscriber, we use the SUB type of the socket
		#socket = context.socket(zmq.SUB)
		connect_str = "tcp://" + self.broker + ":" + self.port
		#print("Collecting updates from weather server proxy at: {}".format(connect_str))
		self.socket.connect(connect_str)

	def subscribe(self):
		# Keep subscribing
		# any subscriber must use the SUBSCRIBE to set a subscription, i.e., tell the
		# system what it is interested in	
		self.socket.setsockopt_string(zmq.SUBSCRIBE, self.zipcode)
		
		# Process 5 updates
		# total_temp = 0
		while True:
			string = self.socket.recv_string()
			# zipcode, temperature, relhumidity, ownership, history = string.split()
			# total_temp += int(temperature)
			print string

	def close(self):
		""" This method closes the PyZMQ socket. """
		self.socket.close(0)

if __name__ == '__main__':
	broker = sys.argv[1] if len(sys.argv) > 1 else "127.0.0.1"
	port = sys.argv[2] if len(sys.argv) > 2 else "5556"
	zipcode = sys.argv[3] if len(sys.argv) > 3 else "10001"
	print('input zip:',zipcode)
	# Python 2 - ascii bytes to unicode str
	if isinstance(zipcode, bytes):
		zipcode = zipcode.decode('ascii')
	sub = Subscriber(broker, port, zipcode)
	#sub.connect_broker()
	sub.subscribe()