import paho.mqtt.client as mqtt #import the client1
import time
############
def on_message(client, userdata, message):
    message_string = str(message.payload.decode("utf-8"))
    print("message received " , message_string)
    print("message topic=",message.topic)
    print("message qos=",message.qos)
    print("message retain flag=",message.retain)
########################################
broker_address="192.168.4.1"
pub_topic = "Base_station"
sub_topic = "Train1"

#broker_address="iot.eclipse.org"
print("Creating new instance")
client = mqtt.Client("P1") #create new instance
client.on_message = on_message #attach function to callback
print("Connecting to broker")
client.connect(broker_address) #connect to broker
client.loop_start() #start the loop

print("Subscribing to topic",sub_topic)
client.subscribe(sub_topic)
print("Publishing message to topic",pub_topic)
client.publish(pub_topic,"This message comes from Base Station")
time.sleep(4) # wait
#client.loop_stop() #stop the loop