应用侧接收MQTT数据流传的信息，有没有例程，我根据教程，时好时坏

数据转发，应用侧接收老失败，有时候可以ClientConf.py:from typing import Optionalclass ClientConf:def __init__(self):# mqtt订阅地址self.__host: Optional[str] = "95e74068ba.st1.iotda-app.cn-north-4.myhuaweicloud.com"# mqtt订阅端口号self.__port: Optional[int] = 8883# mqtt接入凭据access_keyself.__access_key: Optional[str] = "glWckaFu"# mqtt接入凭据access_codeself.__access_code: Optional[str] = "x83VLjH7MAPikrIR36916sAStLoPXEK7"# mqtt订阅topicself.__topic: Optional[str] = "topic456"# 实例Id，同一Region购买多个标准版实例时需要填写该参数self.__instance_id: Optional[str] = "5b6a80f0-75d5-4091-b28a-7809838c524c"# mqtt qosself.__qos = 1# tcp 服务器 IPself.__tcp_ip: Optional[str] = "10.16.64.116"# tcp 服务器端口self.__tcp_port: Optional[int] = 11111@propertydef host(self):return self.__host@host.setterdef host(self, host):self.__host = host@propertydef port(self):return self.__port@port.setterdef port(self, port):self.__port = port@propertydef access_key(self):return self.__access_key@access_key.setterdef access_key(self, access_key):self.__access_key = access_key@propertydef access_code(self):return self.__access_code@access_code.setterdef access_code(self, access_code):self.__access_code = access_code@propertydef topic(self):return self.__topic@topic.setterdef topic(self, topic):self.__topic = topic@propertydef instance_id(self):return self.__instance_id@instance_id.setterdef instance_id(self, instance_id):self.__instance_id = instance_id@propertydef qos(self):return self.__qos@qos.setterdef qos(self, qos):self.__qos = qos@propertydef tcp_ip(self):return self.__tcp_ip@tcp_ip.setterdef tcp_ip(self, tcp_ip):self.__tcp_ip = tcp_ip@propertydef tcp_port(self):return self.__tcp_port@tcp_port.setterdef tcp_port(self, tcp_port):self.__tcp_port = tcp_portMqttClient.py:import osimport sslimport threadingimport timeimport tracebackimport secretsimport socketfrom typing import Optionalfrom ClientConf import ClientConfimport paho.mqtt.client as mqttimport jsonclass MqttClient:def __init__(self, client_conf: ClientConf):print("__init__ 66666")self.__host = client_conf.hostself.__port = client_conf.portself.__access_key = client_conf.access_keyself.__access_code = client_conf.access_codeself.__topic = client_conf.topicself.__instance_id = client_conf.instance_idself.__qos = client_conf.qosself.__tcp_ip = client_conf.tcp_ipself.__tcp_port = client_conf.tcp_portself.__paho_client: Optional[mqtt.Client] = Noneself.__connect_result_code = -1self.__default_backoff = 1000self.__retry_times = 0self.__min_backoff = 1 * 1000 # 1sself.__max_backoff = 30 * 1000 # 30sdef connect(self):print("connect 66666")self.__valid_params()rc = self.__connect()while rc != 0:# 退避重连low_bound = int(self.__default_backoff * 0.8)high_bound = int(self.__default_backoff * 1.0)random_backoff = secrets.randbelow(high_bound - low_bound)backoff_with_jitter = int(pow(2, self.__retry_times)) * (random_backoff + low_bound)wait_time_ms = self.__max_backoff if (self.__min_backoff + backoff_with_jitter) > self.__max_backoff else (self.__min_backoff + backoff_with_jitter)wait_time_s = round(wait_time_ms / 1000, 2)print("client will try to reconnect after " + str(wait_time_s) + " s")time.sleep(wait_time_s)self.__retry_times += 1self.close() # 释放之前的connectionrc = self.__connect()# rc为0表示建链成功，其它表示连接不成功if rc != 0:print("connect with result code: " + str(rc))if rc == 134:print("connect failed with bad username or password, ""reconnection will not be performed")passreturn rcdef __connect(self):try:print("__connect 66666")timestamp = self.current_time_millis()user_name = "accessKey=" + self.__access_key + "|timestamp=" + timestampif self.__instance_id:user_name = user_name + "|instanceId=" + self.__instance_idpass_word = self.__access_codeself.__paho_client = mqtt.Client(mqtt.CallbackAPIVersion.VERSION2, "mqttClient")# 关闭自动重试， 采用手动重试的方式刷新时间戳self.__paho_client._reconnect_on_failure = False# 设置回调函数self._set_callback()# topic放在userdata中，回调函数直接拿topic订阅self.__paho_client.user_data_set(self.__topic)self.__paho_client.username_pw_set(user_name, pass_word)# 当前mqtt broker仅支持TLS1.2context = ssl.SSLContext(ssl.PROTOCOL_TLSv1_2)# 不校验服务端证书context.verify_mode = ssl.CERT_NONEcontext.check_hostname = Falseself.__paho_client.tls_set_context(context)rc = self.__paho_client.connect(self.__host, self.__port)self.__connect_result_code = rcif rc == 0:threading.Thread(target=self.__paho_client.loop_forever, args=(1, False), name="MqttThread").start()# 等待建链time.sleep(1)except Exception as e:self.__connect_result_code = -1print("Mqtt connection error. traceback: " + traceback.format_exc())if self.__paho_client.is_connected():return 0else:return self.__connect_result_codedef __valid_params(self):print("__valid_params 66666")assert self.__access_key is not Noneassert self.__access_code is not Noneassert self.__topic is not None@staticmethoddef current_time_millis():return str(int(round(time.time() * 1000)))def _set_callback(self):print("_set_callback 6666 ")# 当平台响应连接请求时，执行self._on_connect()self.__paho_client.on_connect = self._on_connectprint("_on_disconnect ")# 当与平台断开连接时，执行self._on_disconnect()self.__paho_client.on_disconnect = self._on_disconnectprint("_on_subscribe ")# 当订阅topic时，执行self._on_subscribeself.__paho_client.on_subscribe = self._on_subscribe# 当接收到一个原始消息时，执行self._on_message()print("_on_message ")self.__paho_client.on_message = self._on_messagedef _on_connect(self, client, userdata, flags, rc: mqtt.ReasonCode, properties):print("_on_connect 66666 ")if rc == 0:print("Connected to Mqtt Broker! topic " + self.__topic)client.subscribe(userdata, 1)else:# 只有当用户名或密码错误，才不进行自动重连。# 如果这里不使用disconnect()方法，那么loop_forever会一直进行重连。if rc == 134:self.__paho_client.disconnect()print("Failed to connect. return code :" + str(rc.value) + ", reason" + rc.getName())def _on_subscribe(self, client, userdata, mid, granted_qos, properties):print("_on_subscribe 66666 ")print("Subscribed: " + str(mid) + " " + str(granted_qos) + " topic: " + self.__topic)def _on_message(self, client, userdata, message: mqtt.MQTTMessage):print("_on_message 66666666666")print("topic " + self.__topic + " Received message: " + message.payload.decode())# 通过TCP发送消息try:with socket.socket(socket.AF_INET, socket.SOCK_STREAM) as s:s.connect((self.__tcp_ip, self.__tcp_port))s.sendall(message.payload)print("Message sent over TCP")except Exception as e:print("TCP send error. traceback: " + traceback.format_exc())# def _on_message(self, client, userdata, message: mqtt.MQTTMessage):# print("_on_message 66666666666")# print("topic " + self.__topic + " Received message: " + message.payload.decode())## try:# # 解析收到的 JSON 消息# received_msg = json.loads(message.payload.decode())## # 提取需要的部分# extracted_data = received_msg["notify_data"]["body"]## # 添加上报类型和类型# extracted_data["report_type"] = "Send"# extracted_data["type"] = "货物"## # 将提取和修改后的数据转换回 JSON# extracted_data_str = json.dumps(extracted_data)## # 打印发送的信息# print("Message to be sent over TCP: " + extracted_data_str)## # 通过 TCP 发送消息# with socket.socket(socket.AF_INET, socket.SOCK_STREAM) as s:# s.connect((self.__tcp_ip, self.__tcp_port))# s.sendall(extracted_data_str.encode())# print("Message sent over TCP")# except Exception as e:# print("TCP send error. traceback: " + traceback.format_exc())def _on_disconnect(self, client, userdata, flags, rc, properties):print("Disconnect to Mqtt Broker. topic: " + self.__topic)# 断链后将客户端主动关闭，手动重连刷新时间戳try:self.__paho_client.disconnect()except Exception as e:print("Mqtt connection error. traceback: " + traceback.format_exc())self.connect()def close(self):print("close 66666 ")if self.__paho_client is not None and self.__paho_client.is_connected():try:self.__paho_client.disconnect()print("Mqtt connection close")except Exception as e:print("paho client disconnect failed. exception: " + str(e))else:passMqttDemo.py:import osfrom ClientConf import ClientConffrom MqttClient import MqttClientimport osfrom typing import Optionalfrom huaweicloudsdkcore.auth.credentials import BasicCredentials, DerivedCredentialsfrom huaweicloudsdkcore.region.region import Region as coreRegionfrom huaweicloudsdkcore.exceptions import exceptionsfrom huaweicloudsdkiotda.v5 import *def main():client_conf = ClientConf()client_conf.host = "95e74068ba.st1.iotda-app.cn-north-4.myhuaweicloud.com"client_conf.port = 8883client_conf.topic = "topic456"# mqtt接入凭据access_key可使用环境变量的方式注入client_conf.access_key = "glWckaFu"# mqtt接入凭据a ccess_code可使用环境变量的方式注入client_conf.access_code = "x83VLjH7MAPikrIR36916sAStLoPXEK7"client_conf.instance_id = "5b6a80f0-75d5-4091-b28a-7809838c524c"mqtt_client = MqttClient(client_conf)if mqtt_client.connect() != 0:print("init failed")return# 调用华为IoTDA服务接口if __name__ == "__main__":main()

使用pythonSDK示例失败# coding: utf-8import osfrom huaweicloudsdkcore.auth.credentials import BasicCredentialsfrom huaweicloudsdkcore.auth.credentials import DerivedCredentialsfrom huaweicloudsdkcore.region.region import Region as coreRegionfrom huaweicloudsdkcore.exceptions import exceptionsfrom huaweicloudsdkiotda.v5 import *if __name__ == "__main__":# The AK and SK used for authentication are hard-coded or stored in plaintext, which has great security risks. It is recommended that the AK and SK be stored in ciphertext in configuration files or environment variables and decrypted during use to ensure security.# In this example, AK and SK are stored in environment variables for authentication. Before running this example, set environment variables CLOUD_SDK_AK and CLOUD_SDK_SK in the local environmentak = "jfdjkjCjk8C84"sk = "ljkjQjkfdjhvgdfffjWVzJDUB"endpoint = "85e44068ba.st1.iotda-app.cn-north-4.myhuaweicloud.com"credentials = BasicCredentials(ak, sk).with_derived_predicate(DerivedCredentials.get_default_derived_predicate())client = IoTDAClient.new_builder() \.with_credentials(credentials) \.with_region(coreRegion(id="cn-north-4", endpoint=endpoint)) \.build()try:request = UpdatePropertiesRequest()request.body = DevicePropertiesRequest(services="[{\"service_id\":\"Temperature\",\"properties\":{\"value\":57}}, {\"service_id\":\"Battery\",\"properties\":{\"level\":80}}]")response = client.update_properties(request)print(response)except exceptions.ClientRequestException as e:print(e.status_code)print(e.request_id)print(e.error_code)print(e.error_msg)

在访问过程中，已经能够返回201值，说明连接完成，后使用python继续访问，获得成功，想问下各位是如何解决该问题的。

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B站视频只有芯片教程，请问有没有讲解系统的视频，下面思维导图的视频在哪能找到小熊派IoT开发板系列教程正式发布——免费学习-云社区-华为云 (huaweicloud.com)

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刚开始学习，我看示例的编译目录不是源码目录，请问应该在哪里编译呢

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请问下，如何利用CoAP协议在资源受限的设备上实现物联网通信？