【ESP32+Python】MQTT服务使用例子包含温感和继电器应用

1.MQTT服务推荐使用emqx
2.ESP32基础库，放在目录下名称为umqttsimple.py

import usocket as socket
import ustruct as struct
from ubinascii import hexlify


class MQTTException(Exception):
    pass


class MQTTClient:
    def __init__(
        self,
        client_id,
        server,
        port=0,
        user=None,
        password=None,
        keepalive=0,
        ssl=False,
        ssl_params={},
    ):
        if port == 0:
            port = 8883 if ssl else 1883
        self.client_id = client_id
        self.sock = None
        self.server = server
        self.port = port
        self.ssl = ssl
        self.ssl_params = ssl_params
        self.pid = 0
        self.cb = None
        self.user = user
        self.pswd = password
        self.keepalive = keepalive
        self.lw_topic = None
        self.lw_msg = None
        self.lw_qos = 0
        self.lw_retain = False

    def _send_str(self, s):
        self.sock.write(struct.pack("!H", len(s)))
        self.sock.write(s)

    def _recv_len(self):
        n = 0
        sh = 0
        while 1:
            b = self.sock.read(1)[0]
            n |= (b & 0x7F) << sh
            if not b & 0x80:
                return n
            sh += 7

    def set_callback(self, f):
        self.cb = f

    def set_last_will(self, topic, msg, retain=False, qos=0):
        assert 0 <= qos <= 2
        assert topic
        self.lw_topic = topic
        self.lw_msg = msg
        self.lw_qos = qos
        self.lw_retain = retain

    def connect(self, clean_session=True):
        self.sock = socket.socket()
        addr = socket.getaddrinfo(self.server, self.port)[0][-1]
        self.sock.connect(addr)
        if self.ssl:
            import ussl

            self.sock = ussl.wrap_socket(self.sock, **self.ssl_params)
        premsg = bytearray(b"\x10\0\0\0\0\0")
        msg = bytearray(b"\x04MQTT\x04\x02\0\0")

        sz = 10 + 2 + len(self.client_id)
        msg[6] = clean_session << 1
        if self.user is not None:
            sz += 2 + len(self.user) + 2 + len(self.pswd)
            msg[6] |= 0xC0
        if self.keepalive:
            assert self.keepalive < 65536
            msg[7] |= self.keepalive >> 8
            msg[8] |= self.keepalive & 0x00FF
        if self.lw_topic:
            sz += 2 + len(self.lw_topic) + 2 + len(self.lw_msg)
            msg[6] |= 0x4 | (self.lw_qos & 0x1) << 3 | (self.lw_qos & 0x2) << 3
            msg[6] |= self.lw_retain << 5

        i = 1
        while sz > 0x7F:
            premsg[i] = (sz & 0x7F) | 0x80
            sz >>= 7
            i += 1
        premsg[i] = sz

        self.sock.write(premsg, i + 2)
        self.sock.write(msg)
        # print(hex(len(msg)), hexlify(msg, ":"))
        self._send_str(self.client_id)
        if self.lw_topic:
            self._send_str(self.lw_topic)
            self._send_str(self.lw_msg)
        if self.user is not None:
            self._send_str(self.user)
            self._send_str(self.pswd)
        resp = self.sock.read(4)
        assert resp[0] == 0x20 and resp[1] == 0x02
        if resp[3] != 0:
            raise MQTTException(resp[3])
        return resp[2] & 1

    def disconnect(self):
        self.sock.write(b"\xe0\0")
        self.sock.close()

    def ping(self):
        self.sock.write(b"\xc0\0")

    def publish(self, topic, msg, retain=False, qos=0):
        pkt = bytearray(b"\x30\0\0\0")
        pkt[0] |= qos << 1 | retain
        sz = 2 + len(topic) + len(msg)
        if qos > 0:
            sz += 2
        assert sz < 2097152
        i = 1
        while sz > 0x7F:
            pkt[i] = (sz & 0x7F) | 0x80
            sz >>= 7
            i += 1
        pkt[i] = sz
        # print(hex(len(pkt)), hexlify(pkt, ":"))
        self.sock.write(pkt, i + 1)
        self._send_str(topic)
        if qos > 0:
            self.pid += 1
            pid = self.pid
            struct.pack_into("!H", pkt, 0, pid)
            self.sock.write(pkt, 2)
        self.sock.write(msg)
        if qos == 1:
            while 1:
                op = self.wait_msg()
                if op == 0x40:
                    sz = self.sock.read(1)
                    assert sz == b"\x02"
                    rcv_pid = self.sock.read(2)
                    rcv_pid = rcv_pid[0] << 8 | rcv_pid[1]
                    if pid == rcv_pid:
                        return
        elif qos == 2:
            assert 0

    def subscribe(self, topic, qos=0):
        assert self.cb is not None, "Subscribe callback is not set"
        pkt = bytearray(b"\x82\0\0\0")
        self.pid += 1
        struct.pack_into("!BH", pkt, 1, 2 + 2 + len(topic) + 1, self.pid)
        # print(hex(len(pkt)), hexlify(pkt, ":"))
        self.sock.write(pkt)
        self._send_str(topic)
        self.sock.write(qos.to_bytes(1, "little"))
        while 1:
            op = self.wait_msg()
            if op == 0x90:
                resp = self.sock.read(4)
                # print(resp)
                assert resp[1] == pkt[2] and resp[2] == pkt[3]
                if resp[3] == 0x80:
                    raise MQTTException(resp[3])
                return

    # Wait for a single incoming MQTT message and process it.
    # Subscribed messages are delivered to a callback previously
    # set by .set_callback() method. Other (internal) MQTT
    # messages processed internally.
    def wait_msg(self):
        res = self.sock.read(1)
        self.sock.setblocking(True)
        if res is None:
            return None
        if res == b"":
            raise OSError(-1)
        if res == b"\xd0":  # PINGRESP
            sz = self.sock.read(1)[0]
            assert sz == 0
            return None
        op = res[0]
        if op & 0xF0 != 0x30:
            return op
        sz = self._recv_len()
        topic_len = self.sock.read(2)
        topic_len = (topic_len[0] << 8) | topic_len[1]
        topic = self.sock.read(topic_len)
        sz -= topic_len + 2
        if op & 6:
            pid = self.sock.read(2)
            pid = pid[0] << 8 | pid[1]
            sz -= 2
        msg = self.sock.read(sz)
        self.cb(topic, msg)
        if op & 6 == 2:
            pkt = bytearray(b"\x40\x02\0\0")
            struct.pack_into("!H", pkt, 2, pid)
            self.sock.write(pkt)
        elif op & 6 == 4:
            assert 0

    # Checks whether a pending message from server is available.
    # If not, returns immediately with None. Otherwise, does
    # the same processing as wait_msg.
    def check_msg(self):
        self.sock.setblocking(False)
        return self.wait_msg()

3.使用例子，包括控制板子灯+外接温感+继电器，温感是3秒一上报，继电器和灯是通过MQTT 发送指令控制

import time
import network
from umqttsimple import MQTTClient
import machine
from machine import Pin  # ---- 添加 --------
import ujson
import onewire, ds18x20

# ---- 添加 --------
# 3. 创建LED对应Pin对象
led_pin = Pin(2, Pin.OUT)
# ---- 添加 --------
# ---- 温度 --------
ds_pin = Pin(13)
ds_sensor = ds18x20.DS18X20(onewire.OneWire(ds_pin))
# ---- 温度 --------
# ---- 继电器 -------
p12 = Pin(12, Pin.OUT)
# ---- 继电器 -------
def read_ds_sensor():
    roms = ds_sensor.scan()
    ds_sensor.convert_temp()
    for rom in roms:
        temp = ds_sensor.read_temp(rom)
        if isinstance(temp, float):
            temp = round(temp, 2)
            return temp



def sub_cb(topic, msg):
    # ----收到消息打印 -------
    print(topic, msg)
    # ----消息转JSON -------
    decoded_msg = ujson.loads(msg.decode("utf-8"))
    if "msg" in decoded_msg:
        msg_value = decoded_msg["msg"]
        print("msg:", msg_value)
    # ----订阅判断 -------
    if topic.decode("utf-8") == "ledctl":
        if msg_value == 1:
            # ----灯 继电器关 -------
            led_pin.value(1)
            p12.value(1)
            # ----灯 继电器开 -------
        elif msg_value == 0:
            # ----灯 继电器关 -------
            led_pin.value(0)
            p12.value(0)
            # ----灯 继电器关 -------
   

def mqtt():
    # 获取 ESP32 唯一标识符
    uid = machine.unique_id()
    uid_str = ":".join("{:02X}".format(x) for x in uid)  #       将 UID 转换为字符串格式
    print("UID:", uid_str)
    # 创建mqtt客户端
    client_id = "UID:" + uid_str
    # 创建mqt
    c = MQTTClient(client_id, "MQTT服务端IP")  # 建立一个MQTT客户端
   

    while True:
        try:
            if not c.connect():
                print("连接成功")
                c.set_callback(sub_cb)  # 设置回调函数
            else:
                print("连接失败")
                time.sleep(10)  # 连接失败后等待一段时间再尝试连接
                continue  # 跳过本次循环，重新尝试连接

            c.subscribe(b"ledctl")  # 监控ledctl这个通道，接收控制命令
            while True:
                c.check_msg()
                temperature = read_ds_sensor()  # 读取温度数据
                if temperature is not None:
                    temperature_msg = ujson.dumps({"msg": 3, "temperature": temperature})  # 格式化温度消息
                    if not c.publish(b"temperature", temperature_msg):  # 发送温度消息
                        print("温度消息发送成功")
                    else:
                        print("温度消息发送失败")
                time.sleep(5)
        except Exception as e:
            print(f"MQTT网络发生异常: {e}")
            time.sleep(10)  # 发生异常后等待一段时间再尝试连接
            continue  # 跳过本次循环，重新尝试连接