python - 将参数传递给paho mqtt回调

Question

我是Python的新手，并且每次收到MQTT消息/主题时，我都试图运行一个控件以使RGB LED发光。因此，我创建了一个对象threadObj来运行线程并循环播放脉冲动画。

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

这是主要脚本:

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 类别:

import threading
import time

class ledPulse(object):

    instance_count = 0 #count how many istance of the class are created
    def __init__(self, ledDriver):
        self.status = "OFF"
        self.ledPulseThread = threading.Thread(target=self.ledPulseThread)  # create a thread for our streamV function
        self.ledColor = [30, 40, 50]
        self.ledDriver = ledDriver
        self.msgTopic = ""
        self.counter = 0
        ledPulse.instance_count += 1

    def ledPulseThread(self):
        print("starting thread")
        while self.status == "ON":
            print("nonstop | status = ", self.Status)
            self.ledDriver[0] = [0, 0, 0]
            self.ledDriver.write()
            time.sleep(0.2)
            print("{0} sec | color {2} | driver {3} | instance {4} | deca  {1}".format(self.counter, self.msgTopic, self.ledColor, self.ledDriver.write(), ledPulse.instance_count ))
            self.ledDriver[0] = self.ledColor
            self.ledDriver.write()
            time.sleep(0.2)
            self.counter = self.counter + 1
        print("stopping thread")
        self.counter = 0
        #raise SystemExit

Answer 1

将对象实例作为值放置在字典中(或任何可变对象，如list，如果要更改回调中的值并查看反射(reflect)在主代码中的更改)，则在实例化时将对象实例作为用户数据的一部分传递MQTT客户端。例如:

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

在on_message回调中，您可以在userdata变量中访问此字典。

userdata['myobject'] <- this is your threadObj