paho-mqtt 发布-订阅不能从 Python 中的单独文件工作

Question

我有两个单独的文件用于发布和订阅以测试 mqtt 协议。我维护一个配置文件来存储常见的参数，如 client_id、broker 名称和 topics。

config.py

​​>

broker = "iot.eclipse.org"

# Random alphanumeric string
uid = "id-sfgjrs45ys4jQPlk"

appliances = {
    "room1": [
        "appliance1",
        "appliance2",
        "appliance3",
        "appliance4",
        "appliance5"
    ],
    "room2": [
        "appliance1",
        "appliance2",
        "appliance3"
    ]
}

订阅者.py

​​>

import time
import paho.mqtt.client as mqtt
import config

broker = config.broker
client_id = config.uid

topics = list()
for room, appliances in config.appliances.items():
    for appliance in appliances:
        topics.append(room + "/" + appliance)

def on_message(client, userdata, message):
    print("Topic: " + message.topic)
    print("Message: " + message.payload.decode('utf-8'))

client = mqtt.Client(client_id=client_id)
client.on_message = on_message

print("Connecting to broker... " + broker)
client.connect(broker)

print("Subscribing ")
for topic in topics:
    client.subscribe(topic)

print("Listening")
client.loop_forever()

publisher.py

​​>

import time
import paho.mqtt.client as mqtt
import config

broker = config.broker
client_id = config.uid

topic = "room1/appliance1"
message = "off"

client = mqtt.Client(client_id=client_id)

print("Connecting to broker... " + broker)
client.connect(broker)

print("Publishing ")
client.publish(
    topic=topic,
    payload=message
)
time.sleep(1)
client.disconnect()

如果 subscriber.py 和 publisher.py 保存在同一个文件中，它们似乎可以正常工作，例如：

client.loop_start()
client.publish(
    topic=topic,
    payload=message
)
time.sleep(10)
client.loop_stop()

以下是两者都执行时的日志：

publisher.py 的日志

（在subscriber.py 运行时运行）

Connecting to broker... iot.eclipse.org
Publishing 
Sending PUBLISH (d0, q0, r0, m1), 'b'room1/appliance1'', ... (3 bytes)
Sending DISCONNECT

subsciber.py 的日志

Connecting to broker... iot.eclipse.org
Sending CONNECT (u0, p0, wr0, wq0, wf0, c1, k60) client_id=b'id-sfgjrs45ys4jQPlk'
Subscribing 
Sending SUBSCRIBE (d0, m1) [(b'room1/appliance1', 0)]
Sending SUBSCRIBE (d0, m2) [(b'room1/appliance2', 0)]
Sending SUBSCRIBE (d0, m3) [(b'room1/appliance3', 0)]
Sending SUBSCRIBE (d0, m4) [(b'room1/appliance4', 0)]
Sending SUBSCRIBE (d0, m5) [(b'room1/appliance5', 0)]
Sending SUBSCRIBE (d0, m6) [(b'room2/appliance1', 0)]
Sending SUBSCRIBE (d0, m7) [(b'room2/appliance2', 0)]
Sending SUBSCRIBE (d0, m8) [(b'room2/appliance3', 0)]
Listening
Received CONNACK (0, 0)
Received SUBACK
Received SUBACK
Received SUBACK
Received SUBACK
Received SUBACK
Received SUBACK
Received SUBACK
Received SUBACK
Sending PINGREQ
Received PINGRESP
Sending PINGREQ
Received PINGRESP
Sending CONNECT (u0, p0, wr0, wq0, wf0, c1, k60) client_id=b'id-sfgjrs45ys4jQPlk'
Received CONNACK (0, 0)

我无法弄清楚我做错了什么，以至于订阅者不会收到我的消息。

Answer 1

这是因为您尝试从具有相同客户端 ID uid 的两个单独代码进行连接。

根据规范here

每个连接到服务器的客户端都有一个唯一的 ClientId。

尝试使用不同的客户端 ID，代码应该可以正常工作