我有一個 python 腳本，我正在嘗試使用它來處理 paho mqtt 和時間延遲。我研究了類似的問題，這些問題討論了 paho mqtt，例如Controlling Program with MQTT and Python。我的python腳本如下：這是我的腳本： 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 addressport = 1883 #Broker portuser = "abcde" #Connection usernamepassword = "12345" #Connection passwordclient = 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") #subscribeclient.loop_forever() #then keep listening forever我上面的代碼發生的事情是，只要在有效負載中收到“hello”，它就會打印“good”，但如果在有效負載中收到任何其他內容，包括“hello”，它會繼續打印“good”。它沒有考慮 20 秒的時間。我不確定為什么？我想要實現的目標如下：當開始執行 python 腳本時，腳本應該打印“bad”。這應該停止，直到在有效負載中收到“hello”。一旦收到“hello”，“good”應該打印 20 秒，在這 20 秒內，主題中收到的任何其他消息都應該被忽略，包括“hello”。20 秒后，腳本應該繼續打印“壞”，但只打印一次，循環繼續。
1 回答
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TA貢獻1786條經驗 獲得超13個贊
我使用loop_start()andloop_stop()而不是loop_forever()然后使用 between start，stop我可以創建自己的循環來檢查消息和打印文本。
我使用變量state來控制代碼是在第一個hello( state = "start") 之前還是它得到hello，現在它必須檢查時間并重復文本“好” ( state = "hello") 或者它有 20 秒之后hello并且它沒有打印任何內容 (state = "other")
在內部on_message，我只hello在收到消息時才將狀態更改為hello，而舊狀態則不同hello。
import paho.mqtt.client as mqttClient
import 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 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
# --- main loop ---
last_processed = None
connected = False # signal connection
state = '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()
編輯：
如果您只需要bad一次hello，那么您可以bad在循環之前先打印，然后hello在收到消息時打印，然后time.sleep(20)在打印bad和更改狀態之前打印。
import paho.mqtt.client as mqttClient
import 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 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
# --- main loop ---
connected = False # signal connection
state = 'other' # 'hello'
# ---
client.loop_start()
print('bad') # once at start
try:
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 會很有用，如果你想做更多的事情，它就沒那么有用了。
import paho.mqtt.client as mqttClient
import 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 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
# --- main loop ---
connected = False # signal connection
state = 'other' # 'hello'
# ---
print('bad') # once at start
client.loop_forever()
最終你仍然可以檢查循環時間
import paho.mqtt.client as mqttClient
import 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 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
# --- main loop ---
last_processed = None
connected = False # signal connection
state = 'other' # 'hello'
# ---
client.loop_start()
print('bad') # once at start
try:
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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