这是基于

https://stackoverflow.com/a/13388915/819544发布的答案

我想监视一个数据流并将其推送到类似于上面答案的前端,但是一旦应用程序启动,流就开始生成/监视数据,并且客户端总是看到当前的状态数据流(无论是否从服务器请求数据,它都会继续运行).

我很确定我需要通过线程将数据流与前端分开,但我对线程/异步编程并不是很熟练,并且相信我做错了.也许不是线程我需要使用多处理？这是我正在尝试做的大致(从上面链接的答案修改)：

app.py

#!/usr/bin/env python

from __future__ import division

import itertools

import time

from flask import Flask, Response, redirect, request, url_for

from random import gauss

import threading

app = Flask(__name__)

# Generate streaming data and calculate statistics from it

class MyStreamMonitor(object):

def __init__(self):

self.sum = 0

self.count = 0

@property

def mu(self):

try:

outv = self.sum/self.count

except:

outv = 0

return outv

def generate_values(self):

while True:

time.sleep(.1) # an artificial delay

yield gauss(0,1)

def monitor(self, report_interval=1):

print "Starting data stream..."

for x in self.generate_values():

self.sum += x

self.count += 1

stream = MyStreamMonitor()

@app.route('/')

def index():

if request.headers.get('accept') == 'text/event-stream':

def events():

while True:

yield "data: %s %d\n\n" % (stream.count, stream.mu)

time.sleep(.01) # artificial delay. would rather push whenever values are updated.

return Response(events(), content_type='text/event-stream')

return redirect(url_for('static', filename='index.html'))

if __name__ == "__main__":

# Data monitor should start as soon as the app is started.

t = threading.Thread(target=stream.monitor() )

t.start()

print "Starting webapp..." # we never get to this point.

app.run(host='localhost', port=23423)

静态/ index.html的

Server Send Events Demo

#data {

text-align: center;

}

if (!!window.EventSource) {

var source = new EventSource('/');

source.onmessage = function(e) {

$("#data").text(e.data);

}

}

此代码不起作用. “正在启动webapp …”消息永远不会打印,也不会显示正常的消息,并且访问提供的URL会确认应用程序未运行.

如何使数据监视器在后台运行,以便烧瓶可以访问它所看到的值并将当前状态推送到客户端(更好的是：只要客户端正在监听,就推送当前状态相关价值变化)？