我正在尝试使用Flask启动和停止作为pythonweb应用程序运行的服务。该服务包括一个连续执行的循环,监听麦克风输入,并在输入超过预定义阈值时采取一些操作。我可以让程序在url通过/on参数时开始执行,但是一旦它启动,我就找不到方法停止它。我试过使用请求.args.get监视url参数的状态并观察它从/on到/off的变化,但由于某些原因,程序没有注册我已更改查询字符串以尝试停止执行。有没有更好的方法来执行我的代码并在url参数从/on更改为/off时停止它?非常感谢您的帮助!你知道吗
import alsaaudio, time, audioop
import RPi.GPIO as G
import pygame
from flask import Flask
from flask import request
app = Flask(__name__)
G.setmode(G.BCM)
G.setup(17,G.OUT)
pygame.mixer.init()
pygame.mixer.music.load("/home/pi/OceanLoud.mp3")
@app.route('/autoSoothe', methods=['GET','POST'])
def autoSoothe():
toggle = request.args.get('state')
print(toggle)
if toggle == 'on':
# Open the device in nonblocking capture mode. The last argument could
# just as well have been zero for blocking mode. Then we could have
# left out the sleep call in the bottom of the loop
inp = alsaaudio.PCM(alsaaudio.PCM_CAPTURE,alsaaudio.PCM_NONBLOCK,'null',0)
# Set attributes: Mono, 8000 Hz, 16 bit little endian samples
inp.setchannels(1)
inp.setrate(8000)
inp.setformat(alsaaudio.PCM_FORMAT_S16_LE)
# The period size controls the internal number of frames per period.
# The significance of this parameter is documented in the ALSA api.
# For our purposes, it is suficcient to know that reads from the device
# will return this many frames. Each frame being 2 bytes long.
# This means that the reads below will return either 320 bytes of data
# or 0 bytes of data. The latter is possible because we are in nonblocking
# mode.
inp.setperiodsize(160)
musicPlay = 0
while toggle == 'on':
toggle = request.args.get('state')
print(toggle)
if toggle == 'off':
break
# Read data from device
l,data = inp.read()
if l:
try:
# Return the maximum of the absolute value of all samples in a fragment.
if audioop.max(data, 2) > 20000:
G.output(17,True)
musicPlay = 1
else:
G.output(17,False)
if musicPlay == 1:
pygame.mixer.music.play()
time.sleep(10)
pygame.mixer.music.stop()
musicPlay = 0
except audioop.error, e:
if e.message != "not a whole number of frames":
raise e
time.sleep(.001)
return toggle
if __name__ == "__main__":
app.run(host='0.0.0.0', port=5000, debug=True)
当客户端向Flask服务器发出HTTP请求时,客户端发送一个请求并等待服务器的响应。这意味着当您发送
state
参数时,客户端无法追溯更改它。你知道吗有几种不同的方法来获得你想要的行为。你知道吗
我首先想到的是使用一些异步代码。您可以有这样的代码,当
state
为“on”时启动线程/进程,然后完成请求。这个线程将运行你的音频循环。然后,客户机可以发送另一个请求,但是state
处于“关闭”状态,这可以提醒另一个进程正常停止。你知道吗Here是关于多处理的一些信息;但是,有很多关于如何使用Celery等来使用Flask执行类似操作的信息
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