如何在Flask里开始新的线？线程只能在上启动

Question

我使用Flask webframe控制一个传感器（开始和停止扫描），它连接到一个树莓皮3。一旦我停止扫描（设置了事件），就不能启动新线程，因为线程只能启动一次。那么，有什么建议可以用一个不同的变量名来启动一个新线程？或者有其他选择吗？在

import thread
from flask import Flask, request, url_for, redirect, render_template

def scan(number, duration):
    #Scanner scanning with 2 parameters

class LoopThread(threading.Thread):
    def __init__(self, name, event):
        super(LoopThread,self).__init__()
        self.name = name #can this use as a global variable?
        self.event = event
        self.number = 20
        self.duration = 1

    def run(self):
        print('Starting Thread-'+ str(self.name))
        while not self.event.wait(timeout=1.0):
            self.loop_process()

    def loop_process(self):
        scan(self.number, self.duration)

app = Flask(__name__)

stopevent = threading.Event()
thread = LoopThread(1, stopevent) #what can I change here?

@app.route("/")
def index():
    print("home page")
    return render_template('home.html')

@app.route("/start")
def start():
    thread.start() #how do I change the function variable name everytime?
    return redirect(url_for('index'))

@app.route("/stop")
def stop():
    stopevent.set() #stop the senseor scanning
    thread.join()
    return redirect(url_for('index'))

if __name__ == '__main__':
    app.run("0.0.0.0", debug=True)

Answer 1

一个快速而肮脏的解决方案是在函数中实例化线程，假设只能运行一个线程：

stopevent = None
thread = None

@app.route("/")
def index():
    print("home page")
    return render_template('home.html')

@app.route("/start")
def start():
    global stopevent, thread
    if thread is not None:
        return redirect...
    stopevent = threading.Event()
    thread = LoopThread(1, stopevent) #what can I change here?
    thread.start() #how do I change the function variable name everytime?
    return redirect(url_for('index'))

@app.route("/stop")
def stop():
    global stopevent, thread
    if thread is None:
        return redirect....
    stopevent.set() #stop the senseor scanning
    thread.join()
    stopevent = None
    thread = None
    return redirect(url_for('index'))

这将允许您多次启动和停止线程，但不允许多个并行线程。如果这是你想要的，那么你需要别的东西。在