import paho.mqtt.client as mqtt
import json
 
 
class EstimationWeightUpdate(object):
 
    def __init__(self):
        self.init_mqtt()
        
        
    # The callback for when the client receives a CONNACK response from the server.
    def on_connect(self, client, userdata, flags, rc):
        print("Connected with result code "+str(rc))    #rc的值很重要，为0代表连接成功。
     
        # Subscribing in on_connect() means that if we lose the connection and
        # reconnect then subscriptions will be renewed.
        self.client.subscribe("$SYS/#")    #订阅$SYS/下的所有主题
     
    # The callback for when a PUBLISH message is received from the server.
    def on_message(self, client, userdata, msg):
        print(msg.topic+" "+str(msg.payload))
 
    def init_mqtt(self):
        self.client = mqtt.Client("ADADWWRWFGWERWRWFGTERTER-SUB")
        self.client.username_pw_set("admin", password="longruan123")
        self.client.on_connect = self.on_connect    #连接broker时broker响应的回调
        self.client.on_message = self.on_message    #接收到订阅消息时的回调
        

    def subscribe_update_topic(self):
        self.client.connect("10.71.146.182", 1883, 60)    #连接到broker
        self.client.subscribe("1/1/1", 0)
        self.client.loop_forever() 
        
if __name__ == "__main__":
    ew = EstimationWeightUpdate()
    ew.subscribe_update_topic()