连接阿里云的Python源码

连接阿里云的Python源码，参考网上的代码，然后QT代码也是参照这个写的。

代码中加了很多注释，可以轻易看懂。

# coding=utf-8
# !/usr/bin/python3

import datetime
import time
import hmac
import hashlib
import math

TEST = 0

ProductKey = "a1EdB95bzby"
ClientId = "test123"  # 自定义clientId
DeviceName = "test01"
DeviceSecret = "qU47CjbOh5F26D8isBX6BC5jZ9Uo2Nto"

# signmethod
signmethod = "hmacsha1"
# signmethod = "hmacmd5"

# 当前时间毫秒值
us = math.modf(time.time())[0]#获取当前时间微秒
ms = int(round(us * 1000))#round是默认取整，后面可以加保留的小数位数，不过不是严格四舍五入，结果是毫秒。
#timestamp = str(ms)#转换为字符串
timestamp = "12345"

data = "".join(("clientId", ClientId, "deviceName", DeviceName,    #生成进行哈希算法的原始数据
                "productKey", ProductKey, "timestamp", timestamp
                ))
# print(round((time.time() * 1000)))
print("data:", data)

if "hmacsha1" == signmethod:
    ret = hmac.new(bytes(DeviceSecret, encoding="utf-8"),    #hmacsha1是哈希算法的一种
                   bytes(data, encoding="utf-8"),
                   hashlib.sha1).hexdigest()  #这里的hexdigest直接输出16进制str
elif "hmacmd5" == signmethod:
    ret = hmac.new(bytes(DeviceSecret, encoding="utf-8"),     #md5也是一种信息摘要算法，用以取代md4。2004年，证实MD5算法无法防止碰撞（collision），因此不适用于安全性认证，如SSL公开密钥认证或是数字签名等用途。
                   bytes(data, encoding="utf-8"),
                   hashlib.md5).hexdigest()   #这里的hexdigest直接输出16进制str
else:
    raise ValueError   #当程序出错时,python会自动触发异常,也可以通过raise显示引发异常，一旦执行了raise语句,raise之后的语句不在执行

sign = ret     #ret是哈希算法生成的摘要，这里作为用户密码
print("sign:", sign)

# ======================================================

strBroker = ProductKey + ".iot-as-mqtt.cn-shanghai.aliyuncs.com"     #生成域名，阿里的服务器域名对应好几个IP地址，有一部分原因是为了做负载均衡。
port = 1883    #端口号是1883

client_id = "".join((ClientId,      #生成client_id
                     "|securemode=3",
                     ",signmethod=", signmethod,
                     ",timestamp=", timestamp,
                     "|"))
username = "".join((DeviceName, "&", ProductKey))   #生成用户名
password = sign   #用户密码也就是ret（哈希生成的摘要）

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主要是给在计算机看的，string主要是给人看的，转换桥梁就是编码
                   bytes(data, encoding="utf-8"),
                   hashlib.sha1).hexdigest()
    print("test:", ret)


# ======================================================
# MQTT Initialize.--------------------------------------

try:
    import paho.mqtt.client as mqtt     #导入paho.mqtt，这是一个MQTT协议的JavaScript库，还有一个js库MQTT.js，MQTT.js是需要Node.js的相关环境的
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")


# ======================================================
#这里重写了mqtt库中的部分函数


def on_connect(mqttc, obj, rc):
    print("OnConnetc, rc: " + str(rc))

    mqttc.subscribe("test", 0)

#将消息发送到云端
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)

#接收与处理来自云端的消息
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()