python mqtt loop_forever
时间: 2024-01-17 07:06:12 浏览: 52
`loop_forever()`是一个Python MQTT客户端的方法,用于在连接到MQTT代理并订阅主题后持续接收消息并调用回调函数处理消息。此方法会一直运行,直到调用`client.disconnect()`方法或发生错误导致客户端断开连接。
以下是`loop_forever()`方法的示例代码:
```
import paho.mqtt.client as mqtt
def on_message(client, userdata, message):
print("Received message:", str(message.payload.decode("utf-8")))
mqtt_client = mqtt.Client()
mqtt_client.on_message = on_message
mqtt_client.connect("broker.hivemq.com", 1883, 60)
mqtt_client.subscribe("test/topic")
mqtt_client.loop_forever()
```
在这个例子中,当客户端连接到MQTT代理和成功订阅`test/topic`主题后,`loop_forever()`方法开始无限循环,持续接收来自代理的消息并调用`on_message()`回调函数进行处理。注意,这个方法会一直运行,直到调用`mqtt_client.disconnect()`方法或发生错误导致客户端断开连接。
相关问题
python mqtt tls_python mqtt使用
在Python中使用MQTT协议进行通信可以使用paho-mqtt库,同时也支持TLS/SSL加密。下面是一个简单的示例程序:
```python
import ssl
import paho.mqtt.client as mqtt
# MQTT连接信息
mqtt_broker = "broker.example.com"
mqtt_port = 8883
mqtt_username = "username"
mqtt_password = "password"
# TLS/SSL证书信息
ca_cert = "/path/to/ca.crt"
client_cert = "/path/to/client.crt"
client_key = "/path/to/client.key"
def on_connect(client, userdata, flags, rc):
print("Connected with result code " + str(rc))
client.subscribe("test/topic")
def on_message(client, userdata, msg):
print(msg.topic + " " + str(msg.payload))
client = mqtt.Client()
client.tls_set(ca_cert, certfile=client_cert, keyfile=client_key, cert_reqs=ssl.CERT_REQUIRED, tls_version=ssl.PROTOCOL_TLSv1_2)
client.username_pw_set(mqtt_username, mqtt_password)
client.on_connect = on_connect
client.on_message = on_message
client.connect(mqtt_broker, mqtt_port, 60)
client.loop_forever()
```
在此示例中,我们导入了`ssl`和`paho.mqtt.client`库,然后设置MQTT连接信息和TLS/SSL证书信息。在`on_connect`和`on_message`函数中,我们定义了当连接成功和收到消息时的行为。最后,我们创建了一个MQTT客户端对象,设置TLS/SSL证书,连接到MQTT代理,并开始循环以处理所有MQTT事件。
如果您没有TLS/SSL证书,可以使用以下代码禁用TLS/SSL加密:
```python
import paho.mqtt.client as mqtt
# MQTT连接信息
mqtt_broker = "broker.example.com"
mqtt_port = 1883
mqtt_username = "username"
mqtt_password = "password"
def on_connect(client, userdata, flags, rc):
print("Connected with result code " + str(rc))
client.subscribe("test/topic")
def on_message(client, userdata, msg):
print(msg.topic + " " + str(msg.payload))
client = mqtt.Client()
client.username_pw_set(mqtt_username, mqtt_password)
client.on_connect = on_connect
client.on_message = on_message
client.connect(mqtt_broker, mqtt_port, 60)
client.loop_forever()
```
在此示例中,我们将MQTT端口设置为1883,并禁用了TLS/SSL加密。
python 创建线程执行mqttc.loop_forever()
首先,你需要导入threading模块,然后创建一个新的Thread类的实例,并将要执行的函数作为参数传递给它。例如:
```
import threading
def loop_forever():
mqttc.loop_forever()
thread = threading.Thread(target=loop_forever)
thread.start()
```
这样就可以在新的线程中执行mqttc.loop_forever()函数了。
希望这对你有帮助。
相关推荐
![zip](https://img-home.csdnimg.cn/images/20210720083736.png)
![zip](https://img-home.csdnimg.cn/images/20210720083736.png)
![-](https://csdnimg.cn/download_wenku/file_type_column_c1.png)
![](https://csdnimg.cn/download_wenku/file_type_ask_c1.png)
![](https://csdnimg.cn/download_wenku/file_type_ask_c1.png)
![](https://csdnimg.cn/download_wenku/file_type_ask_c1.png)
![](https://csdnimg.cn/download_wenku/file_type_ask_c1.png)
![](https://csdnimg.cn/download_wenku/file_type_ask_c1.png)
![](https://csdnimg.cn/download_wenku/file_type_ask_c1.png)
![](https://csdnimg.cn/download_wenku/file_type_ask_c1.png)
![](https://csdnimg.cn/download_wenku/file_type_ask_c1.png)
![](https://csdnimg.cn/download_wenku/file_type_ask_c1.png)
![](https://csdnimg.cn/download_wenku/file_type_ask_c1.png)
![](https://csdnimg.cn/download_wenku/file_type_ask_c1.png)
![](https://csdnimg.cn/download_wenku/file_type_ask_c1.png)