前言

由于阿里云物联网套件关于设备认证的文档不够详细，笔者差不多摸索了几天才连接上MQTT。下面是使用Python模拟设备接入阿里云的MQTT。

概述

阿里云物联网套件提供两种接入方式：

1. MQTT客户端域名直连（资源受限设备推荐）
2. 先HTTPS发送授权后再连接MQTT（一些特殊增值服务，比如设备级别的引流）

本文主要介绍第一种接入方式，TCP直连，并提供Python代码示例。

主要参数

连接域名

<ProductKey>.iot-as-mqtt.cn-shanghai.aliyuncs.com:1883

MQTT Connect报文参数

1、mqttClientId

mqttClientId = "<ClientId>"+"|securemode=3,signmethod=hmacsha1,timestamp=132323232|"

2、mqttUsername

使用&拼接<DeviceName>和<ProductKey>。

mqttUsername = "<DeviceName>&<ProductKey>"

3、mqttPassword

把以下参数按字典键名排序，再把键名都拼接起来（没有分隔符）生成content，然后以DeviceSecret为盐，对content进行hma_sha1加密，最后二进制转为十六进制字符串表示。

• clientId
• deviceName
• productKey
• timestamp

mqttPassword = hmac_sha1(DeviceSecret, content).toHexString();

示例

假设

• clientId = 12345
• deviceName = device
• productKey = pk
• timestamp = 789
• signmethod = hmacsha1

content拼接结果：clientId12345deviceNamedeviceproductKeypktimestamp789

注意：不用拼接signmethod参数。

对content以DeviceSecret为盐进行hmacsha1加签后，再转为十六进制字符串，最后结果：FAFD82A3D602B37FB0FA8B7892F24A477F851A14

注意：不需要base64。

最后总结一下生成的参数：

• mqttHost = pk.iot-as-mqtt.cn-shanghai.aliyuncs.com
• mqttPort = 1883
• mqttClientId = 12345|securemode=3,signmethod=hmacsha1,timestamp=789|
• mqttUsername = device&pk
• mqttPassword = FAFD82A3D602B37FB0FA8B7892F24A477F851A14

参数说明

参数	描述
ProductKey	产品Key。从iot套件控制台获取
DeviceName	设备名称。从iot套件控制台获取
DeviceSecret	设别密码，从iot套件控制台获取
signmethod	算法类型，hmacmd5或hmacsha1
clientId	客户端自表示id，建议mac或sn
timestamp	当前时间毫秒值，可选
securemode	目前安全模式，可选值有2 （TLS直连模式）、3（TCP直连模式）

示例代码

填写自己的ProductKey、ClientId、DeviceName、DeviceSecret。

# coding=utf-8 # !/usr/bin/python3 import datetime import time import hmac import hashlib import math TEST = 0 ProductKey = "" ClientId = "12345" # 自定义clientId DeviceName = "" DeviceSecret = "" # signmethod signmethod = "hmacsha1" # signmethod = "hmacmd5" # 当前时间毫秒值 us = math.modf(time.time())[0] ms = int(round(us * 1000)) timestamp = str(ms) data = "".join(("clientId", ClientId, "deviceName", DeviceName, "productKey", ProductKey, "timestamp", timestamp )) # print(round((time.time() * 1000))) print("data:", data) if "hmacsha1" == signmethod: ret = hmac.new(bytes(DeviceSecret, encoding="utf-8"), bytes(data, encoding="utf-8"), hashlib.sha1).hexdigest() elif "hmacmd5" == signmethod: ret = hmac.new(bytes(DeviceSecret, encoding="utf-8"), bytes(data, encoding="utf-8"), hashlib.md5).hexdigest() else: raise ValueError sign = ret print("sign:", sign) # ====================================================== strBroker = ProductKey + ".iot-as-mqtt.cn-shanghai.aliyuncs.com" port = 1883 client_id = "".join((ClientId, "|securemode=3", ",signmethod=", signmethod, ",timestamp=", timestamp, "|")) username = "".join((DeviceName, "&", ProductKey)) password = sign print("="*30) print("client_id:", client_id) print("username:", username) print("password:", password) print("="*30) def secret_test(): DeviceSecret = "secret" data = "clientId12345deviceNamedeviceproductKeypktimestamp789" ret = hmac.new(bytes(DeviceSecret, encoding="utf-8"), bytes(data, encoding="utf-8"), hashlib.sha1).hexdigest() print("test:", ret) # ====================================================== # MQTT Initialize.-------------------------------------- try: import paho.mqtt.client as mqtt except ImportError: print("MQTT client not find. Please install as follow:") print("git clone http://git.eclipse.org/gitroot/paho/org.eclipse.paho.mqtt.python.git") print("cd org.eclipse.paho.mqtt.python") print("sudo python setup.py install") # ====================================================== def on_connect(mqttc, obj, rc): print("OnConnetc, rc: " + str(rc)) mqttc.subscribe("test", 0) def on_publish(mqttc, obj, mid): print("OnPublish, mid: " + str(mid)) def on_subscribe(mqttc, obj, mid, granted_qos): print("Subscribed: " + str(mid) + " " + str(granted_qos)) def on_log(mqttc, obj, level, string): print("Log:" + string) def on_message(mqttc, obj, msg): curtime = datetime.datetime.now() strcurtime = curtime.strftime("%Y-%m-%d %H:%M:%S") print(strcurtime + ": " + msg.topic + " " + str(msg.qos) + " " + str(msg.payload)) on_exec(str(msg.payload)) def on_exec(strcmd): print("Exec:", strcmd) strExec = strcmd # ===================================================== if __name__ == '__main__': if TEST: secret_test() exit(0) mqttc = mqtt.Client(client_id) mqttc.username_pw_set(username, password) mqttc.on_message = on_message mqttc.on_connect = on_connect mqttc.on_publish = on_publish mqttc.on_subscribe = on_subscribe mqttc.on_log = on_log mqttc.connect(strBroker, port, 120) mqttc.loop_forever() 

参考资料

• 阿里云物联网套件 > 设备端接入手册 > 设备基于MQTT接入 > 设备认证

---

终于知道之前为什么总是连接不上了！！！之前文档对password加密的字段是多了「signmethodhmacsha1」字符串！