向paho mqtt callb传递参数

Question

我是Python新手，每次收到MQTT消息/主题时，我都尝试运行一个控件来控制RGB LED的脉冲。所以我创建了一个对象threadObj，以便运行线程并循环脉冲动画。在

我面临的问题是我不知道如何将对象实例传递给on_messagemqtt回调。我一直在寻找部分函数应用程序，但现在我不确定是不是正确的方法。在

这是主脚本：

在

from P9813 import P9813
from safeGPIO import safeGPIO as GPIO
import json
from math import ceil
import os
import threading
import queue
import sys
import subprocess
import threading
import time
from functools import partial
from ledPulse import ledPulse
import paho.mqtt.client as mqtt

def on_connect(client, userdata, flags, rc):
    print("Connected to {0} with result code {1}".format(HOST, rc))
    # Subscribe to any hotword topic --- old code:   # client.subscribe("hermes/hotword/default/detected")
    client.subscribe("hermes/hotword/#")

    # Subscribe to any topic starting with 'hermes/intent/'
    client.subscribe('hermes/intent/#')

def on_message(client, userdata, msg):

    print("- Message received on topic {0}: {1}".format(msg.topic, msg.payload))
    print('* ledPulse instance count {0} nameid {1}'.format(ledPulse.instance_count, threadObj))

    if msg.topic == 'hermes/hotword/default/detected':
        print("Wakeword detected! Wakeword light!")
        #Wakeword light

        print('ledPulseThread.Status -> ON and status {0}'.format(threadObj.status))
        threadObj.Status = "ON"  # T.StreamV could be modified to run at creation and wait for this to change to "ON"
        threadObj.msgTopic = msg.topic
        threadObj.ledDriver = ledDriver
        threadObj.ledColor = LEDS_CYAN
        #threadObj.daemon = True
        threadObj.ledPulseThread.start()  # this calls the T.StreamV function in a separate thread

    if msg.topic == 'hermes/intent/mywai:ShowMarketplace':
        # intent ShowMarketplace light
        print("Intent detected! ShowMarketplace light!")
        ledDriver[0] = LEDS_GREEN
        ledDriver.write()

    if msg.topic == 'hermes/hotword/toggleOn':
        # light for hotword toggled-on
        threadObj.ledColor = LEDS_WARM_WHITE
        threadObj.Status = "OFF"
        print('status ', threadObj.Status)
        print('T.Status -> "OFF"')
        print("Intent detected!  Hotword ended!")
        ledDriver[0] = LEDS_WARM_WHITE
        ledDriver.write()
        #threadObj.ledPulseThread.terminate()  # this calls the T.StreamV function in a separate thread

#########################################################################
# MAIN
#########################################################################
if __name__ == '__main__':
    #main()    
    HOST = 'localhost'
    PORT = 1883
    gpio = GPIO()
    gpio.cleanup()

    # Construct the object
    ledDriver = P9813(32, 33)
    # Create led (R,G,B) list
    leds = [[0, 0, 0]]

    # Define color constants
    #              [R,G,B]
    LED_STRENGTH = 100
    LEDS_OFF = [0, 0, 0]
    LEDS_RED = [LED_STRENGTH, 0, 0]
    LEDS_GREEN = [0, LED_STRENGTH, 0]
    LEDS_BLUE = [0, 0, LED_STRENGTH]
    LEDS_YELLOW = [LED_STRENGTH, LED_STRENGTH, 0]
    LEDS_MAGENTA = [LED_STRENGTH, 0, LED_STRENGTH]
    LEDS_CYAN = [0, LED_STRENGTH, LED_STRENGTH]
    LEDS_WHITE = [LED_STRENGTH, LED_STRENGTH, LED_STRENGTH]
    LEDS_WARM_WHITE = [210, 155, 35]

    # Default light is warm white
    #ledDriver[0] = LEDS_WARM_WHITE
    #ledDriver.write()

    # t1 = threading.Thread(target=loop_test, args=(deca,))
    # t1.start()

    threadObj = ledPulse(ledDriver)  # our thread is actually created here, but is hasn't started yet

    client = mqtt.Client()
    client.on_connect = on_connect
    #client.on_message = on_message
    client.on_message = partial(on_message, threadObj) #https://stackoverflow.com/questions/15331726/how-does-the-functools-partial-work-in-python

    client.connect(HOST, PORT, 60)
    client.loop_forever()

    # Ask the user repeatedly for LED brightness setting
    try:
        while (True):
            str = raw_input("Input R, G, B [Enter] or Ctrl-C to quit. R, G, B range from 0 - 255: ")
            leds[0] = list(map(int, str.split(",")))
            print(leds[0])
            ledDriver[0] = leds[0]
            ledDriver.write()
    except keyboardInterrupt:
        print("\r")
    except:
        print(str)

    # Turn off LEDs before we quit
    leds[0] = [0, 0, 0]
    ledDriver[0] = leds[0]
    ledDriver.write()

ledPulse类：

在

^{pr2}$

Answer 1

将对象实例作为一个值放入字典（或者任何可变对象，如list，如果您想更改回调中的值并查看主代码中反映的更改），然后在实例化MQTT客户机时将对象实例作为userdata的一部分传递。例如：

client_userdata = {'myobject':threadObj}
client = mqtt.Client(userdata=client_userdata)

在on_消息回调中，可以在userdata变量中访问此字典。在

^{pr2}$