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WebSocket服务器在python中定期发送消息

2019-08-31 11:59:20 作者：互联网

我在python中有一个龙卷风web服务器：

import tornado.httpserver
import tornado.websocket
import tornado.ioloop
from tornado.ioloop import IOLoop
import tornado.web
import time
import   threading
import sys
from datetime import datetime
from datetime import timedelta

def sample():
    print 'hiiiii'
    threading.Timer(10, sample).start()

class WSHandler(tornado.websocket.WebSocketHandler):

    def open(self):
        print 'new connection'

    def on_message(self, message):
        self.write_message(message)  
        self.msg('hellooooooo')
        print message

    def msg(self,message):
        self.write_message(message)
        threading.Timer(10, self.msg('in timer')).start()
        print 'in msg'+message
    def on_close(self):
        print 'connection closed'

application = tornado.web.Application([
    (r'/', WSHandler),
])

if __name__ == "__main__":
    http_server = tornado.httpserver.HTTPServer(application)
    http_server.listen(8888)
    interval_ms=120
    main_loop=tornado.ioloop.IOLoop.instance()
main_loop.start()

而客户是

<html>
<head>
<script> 

function fun(){

    alert("in fun()");

    var val=document.getElementById("txt");
    var ws = new WebSocket("ws://localhost:8888");

    ws.onopen = function(evt) { alert("Connection open ...");
    ws.send(val.value); };
    ws.onmessage = function(evt) {
         alert("from server: "+evt.data);
    }

    ws.onclose = function(evt) { 
        alert("Connection closed.");
    }
}

</script>

</head>
<body bgcolor="#FFFFFF">
    <input type="text" id="txt" />
    <button onClick="fun()">click</button>
</body>
</html>

我想定期向客户端收到消息.但是当我尝试这个时,我得到了这个错误：RunTimeError：超过最大递归深度.请帮我解决这个问题.另外,我们如何知道连接到服务器的客户端是什么？

解决方法:

这是使用PeriodicCallback的最小示例.

import tornado.httpserver
import tornado.websocket
import tornado.ioloop
from tornado.ioloop import PeriodicCallback
import tornado.web

class WSHandler(tornado.websocket.WebSocketHandler):
    def open(self):
        self.callback = PeriodicCallback(self.send_hello, 120)
        self.callback.start()

    def send_hello(self):
        self.write_message('hello')

    def on_message(self, message):
        pass

    def on_close(self):
        self.callback.stop()

application = tornado.web.Application([
    (r'/', WSHandler),
])

if __name__ == "__main__":
    http_server = tornado.httpserver.HTTPServer(application)
    http_server.listen(8888)
    tornado.ioloop.IOLoop.instance().start()

标签：python,websocket,tornado,periodic-task
来源： https://codeday.me/bug/20190831/1775525.html