MQTT和时间延迟
我有一个 python 脚本，我正在尝试使用它来处理 paho mqtt 和时间延迟。我研究了类似的问题，这些问题讨论了 paho mqtt，例如Controlling Program with MQTT and Python。我的python脚本如下：
这是我的脚本：
import paho.mqtt.client as mqttClient
import time
import subprocess
import os
global lastprocessed, Connected
lastprocessed = None
Connected = False #global variable for the state of the connection
def on_connect(client, userdata, flags, rc):
if rc == 0:
print("Connected to broker")
global Connected
Connected = True #Signal connection
else:
print("Connection failed")
def on_message(client, userdata, message):
global lastprocessed
if message.payload.decode() == "hello":
lastprocessed = time.time()
if lastprocessed and time.time() - lastprocessed < 20:
print("good")
broker_address= "192.168.1.111" #Broker address
port = 1883 #Broker port
user = "abcde" #Connection username
password = "12345" #Connection password
client = mqttClient.Client("Python") #create new instance
client.username_pw_set(user, password=password) #set username and password
client.on_connect= on_connect #attach function to callback
client.on_message= on_message #attach function to callback
client.connect(broker_address,port,60) #connect
client.subscribe("home/OpenMQTTGateway/433toMQTT") #subscribe
client.loop_forever() #then keep listening forever
我上面的代码发生的事情是，只要在有效负载中收到“hello”，它就会打印“good”，但如果在有效负载中收到任何其他内容，包括“hello”，它会继续打印“good”。它没有考虑 20 秒的时间。我不确定为什么？
我想要实现的目标如下：
当开始执行 python 脚本时，脚本应该打印“bad”。
这应该停止，直到在有效负载中收到“hello”。
一旦收到“hello”，“good”应该打印 20 秒，在这 20 秒内，主题中收到的任何其他消息都应该被忽略，包括“hello”。
20 秒后，脚本应该继续打印“坏”，但只打印一次，循环继续。
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开满天机
我使用loop_start()andloop_stop()而不是loop_forever()然后使用 between start，stop我可以创建自己的循环来检查消息和打印文本。我使用变量state来控制代码是在第一个hello( state = "start") 之前还是它得到hello，现在它必须检查时间并重复文本“好” ( state = "hello") 或者它有 20 秒之后hello并且它没有打印任何内容 (state = "other")在内部on_message，我只hello在收到消息时才将状态更改为hello，而旧状态则不同hello。import paho.mqtt.client as mqttClientimport time# --- functions ---def on_connect(client, userdata, flags, rc): #global state global connected if rc == 0: print("Connected to broker") connected = True else: print("Connection failed")def on_message(client, userdata, message): global state global last_processed if message.payload.decode() == "hello": if state != 'hello': state = 'hello' last_processed = time.time() # OR #if state != 'hello': # if message.payload.decode() == "hello": # state = 'hello' # last_processed = time.time()# --- main ---broker_address = "192.168.1.111" # broker addressport = 1883 # broker portuser = "abcde" # connection usernamepassword = "12345" # connection password# ---client = mqttClient.Client("Python") # create new instanceclient.username_pw_set(user, password=password) # set username and passwordclient.on_connect= on_connect # attach function to callbackclient.on_message= on_message # attach function to callbackclient.connect(broker_address, port, 60) # connectclient.subscribe("home/OpenMQTTGateway/433toMQTT") # subscribe# --- main loop ---last_processed = Noneconnected = False # signal connectionstate = 'start' # 'start', 'hello', 'other', 'not connected' # ---client.loop_start()try: while True: if not connected: print('not connected') if state == 'start': print('bad') if state == 'hello': if last_processed and time.time() - last_processed < 20: print("good", time.time() - last_processed, end='\r') # '\r` to write it in the same line. else: print('bad') state = 'other' last_processed = None if state == 'other': pass time.sleep(1.0) # to slow down example except KeyboardInterrupt: print('KeyboardInterrupt') client.loop_stop()编辑：如果您只需要bad一次hello，那么您可以bad在循环之前先打印，然后hello在收到消息时打印，然后time.sleep(20)在打印bad和更改状态之前打印。import paho.mqtt.client as mqttClientimport time# --- functions ---def on_connect(client, userdata, flags, rc): #global state global connected if rc == 0: print("Connected to broker") connected = True else: print("Connection failed")def on_message(client, userdata, message): global state message = message.payload.decode() if state != 'hello': if message == 'hello': state = 'hello' print('good') # once when start `hello` else: print('msg:', message) # --- main ---broker_address = "192.168.1.111" # broker addressport = 1883 # broker portuser = "abcde" # connection usernamepassword = "12345" # connection password# ---client = mqttClient.Client("Python") # create new instanceclient.username_pw_set(user, password=password) # set username and passwordclient.on_connect= on_connect # attach function to callbackclient.on_message= on_message # attach function to callbackclient.connect(broker_address, port, 60) # connectclient.subscribe("home/OpenMQTTGateway/433toMQTT") # subscribe# --- main loop ---connected = False # signal connectionstate = 'other' # 'hello'# ---client.loop_start()print('bad') # once at starttry: while True: if state == 'hello': time.sleep(20) print('bad') # once when end `hello` state = 'other' time.sleep(1.0) # to slow down example except KeyboardInterrupt: print('KeyboardInterrupt') client.loop_stop()使用threading.Timerinstead of time.sleep()because sleep()blocks loop 会很有用，如果你想做更多的事情，它就没那么有用了。import paho.mqtt.client as mqttClientimport threading# --- functions ---def on_connect(client, userdata, flags, rc): #global state global connected if rc == 0: print("Connected to broker") connected = True else: print("Connection failed")def on_message(client, userdata, message): global state message = message.payload.decode() if state != 'hello': if message == 'hello': state = 'hello' print('good') # once when start `hello` threading.Timer(20, end_hello).start() else: print('msg:', message) def end_hello(): global state print('bad') # once when end `hello` state = 'other'# --- main ---broker_address = "192.168.1.111" # broker addressport = 1883 # broker portuser = "abcde" # connection usernamepassword = "12345" # connection password# ---client = mqttClient.Client("Python") # create new instanceclient.username_pw_set(user, password=password) # set username and passwordclient.on_connect= on_connect # attach function to callbackclient.on_message= on_message # attach function to callbackclient.connect(broker_address, port, 60) # connectclient.subscribe("home/OpenMQTTGateway/433toMQTT") # subscribe# --- main loop ---connected = False # signal connectionstate = 'other' # 'hello'# ---print('bad') # once at startclient.loop_forever()最终你仍然可以检查循环时间import paho.mqtt.client as mqttClientimport time# --- functions ---def on_connect(client, userdata, flags, rc): #global state global connected if rc == 0: print("Connected to broker") connected = True else: print("Connection failed")def on_message(client, userdata, message): global state global last_processed message = message.payload.decode() if state != 'hello': if message == 'hello': state = 'hello' last_processed = time.time() print('good') # once when start `hello` else: print('msg:', message) # --- main ---broker_address = "192.168.1.111" # broker addressport = 1883 # broker portuser = "abcde" # connection usernamepassword = "12345" # connection password# ---client = mqttClient.Client("Python") # create new instanceclient.username_pw_set(user, password=password) # set username and passwordclient.on_connect= on_connect # attach function to callbackclient.on_message= on_message # attach function to callbackclient.connect(broker_address, port, 60) # connectclient.subscribe("home/OpenMQTTGateway/433toMQTT") # subscribe# --- main loop ---last_processed = Noneconnected = False # signal connectionstate = 'other' # 'hello'# ---client.loop_start()print('bad') # once at starttry: while True: if state == 'hello': if time.time() >= last_processed + 20: print('bad') # once when end `hello` state = 'other' time.sleep(1.0) # to slow down example except KeyboardInterrupt: print('KeyboardInterrupt') client.loop_stop()
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