保持WebSocket连接活跃

Question

我正在研究WebSocket协议，想用Python在后台实现一个简单的回声服务。现在看起来运行得不错，但连接在建立后马上就断开了。

这是我的客户端代码：

<!doctype html>
<head>
<script type="text/javascript" src="jquery.js"></script>
<script type="text/javascript">
function Client()
{
    //var ws = new WebSocket("ws://echo.websocket.org"); // this works fine
    var ws = new WebSocket("ws://localhost:8000");
    ws.onopen = function(e){ $("#response").append(">> Connected<br />"); }
    ws.onclose = function(e){ $("#response").append(">> Disconnected<br />"); }
    ws.onerror = function(e){ $("#response").append(">> ERROR: " + e.data + "<br />"); }
    ws.onmessage = function(e){ $("#response").append("> " + e.data + "<br />"); }

    this.sendCmd = function()
    {
        var message = $("#cmd").val();
        $("#response").append(message + "<br />");
        ws.send(message);
        return false;
    }

    this.disconnect = function()
    {
        ws.close();
    }
}

// onload
$(function() {
    $("#response").append(">> Connecting<br />");

    client = new Client();

    $("#send").click(client.sendCmd);
    $("#disconnect").click(client.disconnect);
});
</script>
</head>
<body>
<input type="text" name="cmd" id="cmd" /> | <a href="#" id="send">Send</a> | <a href="#" id="disconnect">Disconnect</a><br />
<hr />
<span id="response"></span>
</body>
</html>

这是服务器代码：

import SocketServer
import socket
from hashlib import sha1
from base64 import b64encode

PORT = 8000
MAGIC = "258EAFA5-E914-47DA-95CA-C5AB0DC85B11"

class Handler(SocketServer.BaseRequestHandler):
    # incoming connection
    def setup(self):
        self.data = self.request.recv(1024).strip()
        print "connection established", self.client_address
        self.headers = self.headsToDict(self.data.split("\n"))

    # incoming message
    def handle(self):
        # its a handshake
        if "Upgrade" in self.headers and self.headers["Upgrade"] == "websocket":
            key = self.headers["Sec-WebSocket-Key"]
            accept = b64encode(sha1(key + MAGIC).hexdigest().decode('hex'))
            response = "HTTP/1.1 101 Web Socket Protocol Handshake\r\n" # "HTTP/1.1 101 Switching Protocols\r\n"
            print "< HTTP/1.1 101 Web Socket Protocol Handshake" # "HTTP/1.1 101 Switching Protocols\r\n"
            response += "Upgrade: websocket\r\n"
            print "< Upgrade: websocket"
            response += "Connection: Upgrade\r\n"
            print "< Connection: Upgrade"
            response += "Sec-WebSocket-Accept: "+accept+"\r\n\r\n"
            print "< Sec-WebSocket-Accept: "+accept
            self.request.send(response)
        # its a normal message, echo it back
        else:
            print self.data
            self.request.send(self.data)

    # connection dropped
    def finish(self):
        print "connection lost", self.client_address

    # convert a list of headers to a dictionary for convenience 
    def headsToDict(self, hdata):
        rzygi = {}
        for item in hdata:
            print '>', item
            item = item.split(':')
            if len(item) > 1:
                rzygi[item[0].strip()] = item[1].strip()
        return rzygi

server = SocketServer.TCPServer(("", PORT), Handler)
server.socket_type = socket.SOCK_STREAM # didnt help
print "serving at port", PORT
try:
    server.serve_forever()
except KeyboardInterrupt:
    pass
server.server_close()

正如我提到的，连接成功建立了，但随即就断开了。这让我觉得代码是对的，但似乎缺少了什么东西来保持连接。以下是服务器的输出：

serving at port 8000
connection established ('127.0.0.1', 52633)
> GET / HTTP/1.1
> Upgrade: websocket
> Connection: Upgrade
> Host: localhost:8000
> Sec-WebSocket-Origin: http://localhost
> Sec-WebSocket-Key: qWGnhdFQ6l8Xs9awgQURfA==
> Sec-WebSocket-Version: 8
< HTTP/1.1 101 Web Socket Protocol Handshake
< Upgrade: websocket
< Connection: Upgrade
< Sec-WebSocket-Accept: fei4E4LQvPnf4y2ilebVsxRofvc=
connection lost ('127.0.0.1', 52633)

我该如何保持连接不掉线呢？

编辑：服务器代码的注释

连接管理网络协议 websocket 实时通信回声服务断线重连

保持WebSocket连接活跃

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