应用Python 实现MQTT Client

#coding:utf-8

#!/usr/bin/python3
import  json
import  os
import  binascii
import  asn1tools
import  sys
import  paho.mqtt.client as mqtt
import  requests
import  logging
from  enum  import  Enum
from  queue  import  Queue

__all__  =  [ "MQTTClient" ]

class  MQTTClient:

    def  __init__( self ,host, port, qos, timeout, log):
        self .host  =  host
        self .port  =  port
        self .qos  =  qos
        self .queue  =  Queue()
        self .mqtt_client  =  None
        self .timeout  =  timeout
        self .log  =  log

    def  on_message( self , client, userdata, msg):
        self .log.debug( 'get a message: %s'  %  msg)
        self .queue.put(msg)

    def  subscribe( self , topic):
        self .mqtt_client.subscribe(topic,  self .qos)
        self .log.debug( 'subscribe to %s'  %  topic)

    def  unsubscribe( self , topic):
        self .mqtt_client.unsubscribe(topic)
        self .log.debug( 'unsubscribe %s'  %  topic)

    def  receive_msg( self , timeout = None ):
        self .log.debug( 'waiting for message.' )
        if  timeout  is  None :
        timeout  =  self .timeout
        return  self .queue.get(timeout = timeout)

    def  publish( self , topic, blob):
        self .mqtt_client.publish(topic, blob)

    def  loop_start( self ):
        if  self .mqtt_client  is  None :
        self .mqtt_client  =  mqtt.Client()
        self .mqtt_client.on_message  =  self .on_message
        self .mqtt_client.connect( self .host,  self .port,  self .timeout)
        self .mqtt_client.loop_start()

    def  loop_stop( self ):
        if  self .mqtt_client  is  not  None :
        self .mqtt_client.loop_stop()
        self .mqtt_client.disconnect()
        self .mqtt_client  =  None