本篇文章介紹mqtt基于python語(yǔ)言在生產(chǎn)環(huán)境的使用

paho-mqtt的安裝

pip install paho-mqtt #可以指定版本paho-mqtt==1.5.0

import re
import json
from inspect import isfunction
import paho.mqtt.client as mqtt
from settings import Config


class EMQClient(object):
    '''
    EMQx Mqtt client class
    usage:
        client = EMQClient(config=config)
    '''
    # MQTT client
    client = None
    # MQTT message callback handlers
    message_handlers = {'common': []}
    # MQTT config dict
    config = None
    # callback handler
    handlers = {}

    def __init__(self, config, **kwargs):
        self.config = {kv[0].lower(): kv[1] for kv in config.items()}
        if 'handlers' in kwargs and isinstance(kwargs['handlers'], dict):
            self.handlers = kwargs['handlers']

        self.client = mqtt.Client(
            client_id=self.config['client_id'] if 'client_id' in self.config else None)
        self.client.on_connect = self.on_connect
        self.client.on_disconnect = self.on_disconnect
        self.client.on_message = self.on_message
        self.client.on_subscribe = self.on_subscribe

    def connect(self):
        '''connect to the mqtt server. '''
        self.client.username_pw_set(
            self.config['username'] if 'username' in self.config else None, self.config['password'])
        # 'admin', '123456')
        self.client.connect(
            self.config['host'], self.config['port'],
            keepalive=self.config['keepalive'] if 'keepalive' in self.config else 60)
        self.client.loop_start()

    def disconnect(self):
        self.client.loop_stop()

    def set_handler(self, handler, func):
        '''
        add callback hanlder
        :param type: handler type
        :param handler: handle message function
        '''
        if handler not in ['connect_handler', 'disconnect_handler', 'subscribe_handler']:
            return False

        self.handlers[handler] = func

    def add_message_handler(self, handler, topic='common'):
        '''
        add message hanlder
        :param handler: handle message function
        :param topic: handle the assigned topic message, `common` means will handle all messages
        '''
        if topic not in self.message_handlers:
            self.message_handlers[topic] = []

        self.message_handlers[topic].append(handler)

    def on_connect(self, client, userdata, flags, rc):
        '''
        callback func when client connected to the mqtt server.
        rc  0：連接成功
            1：連接被拒絕-協(xié)議版本不正確
            2：連接被拒絕-無(wú)效的客戶(hù)端標(biāo)識(shí)符
            3：連接被拒絕-服務(wù)器不可用
            4：連接被拒絕-用戶(hù)名或密碼錯(cuò)誤
            5：連接被拒絕-未經(jīng)授權(quán)
            6-255：當(dāng)前未使用渔扎。
        '''
        print(client, userdata, flags, rc)
        try:
            'connect_handler' in self.handlers and isfunction(self.handlers['connect_handler']) and self.handlers[
                'connect_handler'](self)
        except Exception as e:
            print(e)

    def on_disconnect(self, client, userdata, rc):
        'disconnect_handler' in self.handlers and isfunction(self.handlers['disconnect_handler']) and self.handlers[
            'disconnect_handler'](userdata=userdata, rc=rc)

    def on_subscribe(self, client, userdata, mid, granted_qos):
        'subscribe_handler' in self.handlers and isfunction(self.handlers['subscribe_handler']) and self.handlers[
            'subscribe_handler'](userdata=userdata, mid=mid, granted_qos=granted_qos)

    def on_message(self, client, userdata, message):
        '''
        handle the message when a PUBLISH message is received from the server
        handlers should not set blocked
        '''
        # print(message.payload)
        for topic in self.message_handlers.keys():
            if topic == 'common':
                continue

            regex = re.compile(
                '^{}$'.format(topic.replace('+', '[^\/\s]+').replace('#', '\S+').replace('/', '\/').replace('$', '\$')))
            if regex.match(message.topic):
                for handler in self.message_handlers.get(topic, []):
                    handler(message.payload)

        # call common topic handlers
        for handler in self.message_handlers['common']:
            handler(message)

    def subscribe(self, topic, **kwargs):
        '''
        subscribe topic message
        default set qos to 0
        '''
        print(topic)
        return self.client.subscribe(
            topic, **kwargs)

    def publish(self, topic, message, **kwargs):
        '''publish message through topic'''
        return self.client.publish(topic, json.dumps(message, ensure_ascii=False), **kwargs)

    def unsubscribe(self, topic, properties=None):
        '''unsubscribe topic'''
        return self.client.unsubscribe(topic, properties=properties)

emq_client = EMQClient(config=Config.MQTT_CONFIG)
emq_client.set_handler('connect_handler', connect_handler)
emq_client.connect()