這是基于

https://stackoverflow.com/a/13388915/819544發(fā)布的答案

我想監(jiān)視一個(gè)數(shù)據(jù)流并將其推送到類似于上面答案的前端,但是一旦應(yīng)用程序啟動(dòng),流就開始生成/監(jiān)視數(shù)據(jù),并且客戶端總是看到當(dāng)前的狀態(tài)數(shù)據(jù)流(無論是否從服務(wù)器請求數(shù)據(jù),它都會(huì)繼續(xù)運(yùn)行).

我很確定我需要通過線程將數(shù)據(jù)流與前端分開,但我對線程/異步編程并不是很熟練,并且相信我做錯(cuò)了.也許不是線程我需要使用多處理？這是我正在嘗試做的大致(從上面鏈接的答案修改)：

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)

靜態(tài)/ 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);

}

}

nothing received yet

此代碼不起作用. “正在啟動(dòng)webapp …”消息永遠(yuǎn)不會(huì)打印,也不會(huì)顯示正常的消息,并且訪問提供的URL會(huì)確認(rèn)應(yīng)用程序未運(yùn)行.

如何使數(shù)據(jù)監(jiān)視器在后臺(tái)運(yùn)行,以便燒瓶可以訪問它所看到的值并將當(dāng)前狀態(tài)推送到客戶端(更好的是：只要客戶端正在監(jiān)聽,就推送當(dāng)前狀態(tài)相關(guān)價(jià)值變化)？

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