收到消息后Python MQTT重置计时器

Question

我从线程“python MQTT Connect only for a limited time”中得到了下面的python脚本。你知道吗

#!/usr/bin/python
import sys
import paho.mqtt.client as mqtt
import time

def on_message(client, userdata, msg):
        if msg.topic == "foo/bar":
                print ("test successful! Message = ", str(msg.payload.decode("utf-8")))
                startTime = time.time()


def on_connect(client, userdata, flags, rc):
        client.subscribe("foo/bar")
        print("Client connected")

client = mqtt.Client("Python1", clean_session=True)
try:
        client.connect("localhost")
except:
        print ("ERROR: Could not connect to MQTT")

client.on_connect = on_connect
client.on_message = on_message
startTime = time.time()
waitTime = 10

while True:
        client.loop()
        elapsedTime = time.time() - startTime
        print("Elapsed time: ", elapsedTime)

        if elapsedTime > waitTime:
                client.disconnect()
                break

客户端将等待10秒钟，如果在10秒钟内没有收到任何消息，则客户端将断开连接。你知道吗

我现在要做的是，每当客户端接收到消息时，我都希望将startTime重置回当前时间，这样客户端将保持连接，并且不会在10秒后终止，但我不确定应该在哪里修改编码来实现它。你知道吗

Answer 1

代码几乎是正确的，您只需要将startTime回调中的on_message标记为全局，这样python就不会仅仅创建一个新的局部变量。你知道吗

def on_message(client, userdata, msg):
        if msg.topic == "foo/bar":
                print ("test successful! Message = ", str(msg.payload.decode("utf-8")))
                global startTime
                startTime = time.time()