将python连接到javascript进行双向通信

connecting python to javascript for two-direction communication

本文关键字：双向通信 javascript python 连接      更新时间：2023-09-26

我想通过python提供来自javascript代码的查询。但我在这方面一点经验都没有。我想构建的是这样的东西：

1.request.js：

open_connection('server.py');
for (var i=0; i<10; i++)
    document.write(request_next_number());
close_connection('server.py')

2.server.py

x = 0
while connected:
    if request:
        send(x)
        x = x + 1

我听说过JSON，但不知道是否应该使用它。（？）

你能给我一些代码示例或指导如何实现上面的两个文件吗？

您需要的是python端的套接字服务器和javascript端的客户端/请求服务器。

对于python服务器端，请参阅SocketServer（也就是从那里获得的示例），您必须确保套接字通过NAT（可能是端口转发）。另一种选择是Twisted，这是一个非常强大的框架，我相信它具有通过NAT发送数据的功能。

import SocketServer
class MyTCPHandler(SocketServer.BaseRequestHandler):
    """
    The RequestHandler class for our server.
    It is instantiated once per connection to the server, and must
    override the handle() method to implement communication to the
    client.
    """
    def handle(self):
        # self.request is the TCP socket connected to the client
        self.data = self.request.recv(1024).strip()
        print "{} wrote:".format(self.client_address[0])
        print self.data
        # just send back the same data, but upper-cased
        self.request.sendall(self.data.upper())
if __name__ == "__main__":
    HOST, PORT = "localhost", 9999
    # Create the server, binding to localhost on port 9999
    server = SocketServer.TCPServer((HOST, PORT), MyTCPHandler)
    # Activate the server; this will keep running until you
    # interrupt the program with Ctrl-C
    server.serve_forever()

在JavaScript上有许多允许套接字连接的框架，以下是一些

  • Socket IO

示例：

<script src="/socket.io/socket.io.js"></script>
<script>
  var socket = io.connect('http://localhost');
  socket.on('news', function (data) {
    console.log(data);
    socket.emit('my other event', { my: 'data' });
  });
</script>
  • 你甚至可以使用HTML5 Web Sockets

示例：

var connection = new WebSocket('ws://IPAddress:Port');
connection.onopen = function () {
  connection.send('Ping'); // Send the message 'Ping' to the server
};

  • 此外，请参阅本书Javascript: The Definitive Guide第22章的一部分，https://www.inkling.com/read/javascript-definitive-guide-david-flanagan-6th/chapter-22/web-sockets

  • 最后，看一下jssockets

示例：

_jssocket.setCallBack(event, callback);
_jssocket.connect(ip,port);
_jssocket.write(message);
_jssocket.disconnect();

希望得到帮助！

WebSocket的一个例子，我用它将图像传输到Web服务器并流式传输我的屏幕。

stream.html

<!DOCTYPE HTML>
<meta charset = utf-8>
<html>
    <header>
        <title>Stream</title>
        <script type="text/javascript" src="js/request.js"></script>
    </header>
    <body onload="doLoad()">
        <div id="canvasWrapper">
            <canvas id="display"></canvas>
        </div>
    </body>
</html>

request.js

var disp;
var dispCtx;
var im;
var ws;
function doLoad() {
    disp = document.getElementById("display");
    dispCtx = disp.getContext("2d");
    im = new Image();
    im.onload = function() {
    disp.setAttribute("width", im.width);
    disp.setAttribute("height", im.height);
    dispCtx.drawImage(this, 0, 0);
  };
    im.src = "img/img_not_found.png";
    ws = new WebSocket("ws://127.0.0.1:50007");
    ws.onmessage = function (evt) {
        im.src = "data:image/png;base64," + evt.data;
    }
}

服务器.py

from autobahn.twisted.websocket import WebSocketServerProtocol, WebSocketServerFactory
import base64
import sys
from twisted.python import log
from twisted.internet import reactor
class MyServerProtocol(WebSocketServerProtocol):
    def onConnect(self, request):
        print("Client connecting: {}".format(request.peer))
    def onOpen(self):
        print("WebSocket connection open.")
        def hello():
            with open("/var/www/html/img/image.png", "rb") as image_file:
                encoded_string = base64.b64encode(image_file.read())
            self.sendMessage(encoded_string.encode('utf8'))
            self.factory.reactor.callLater(0.2, hello)
        # start sending messages every 20ms ..
        hello()
    def onMessage(self, payload, isBinary):
        if isBinary:
            print("Binary message received: {} bytes".format(len(payload)))
        else:
            print("Text message received: {}".format(payload.decode('utf8')))
        # echo back message verbatim
        self.sendMessage(payload, isBinary)
    def onClose(self, wasClean, code, reason):
        print("WebSocket connection closed: {}".format(reason))

if __name__ == '__main__':
    log.startLogging(sys.stdout)
    factory = WebSocketServerFactory(u"ws://127.0.0.1:50007")
    factory.protocol = MyServerProtocol
    # factory.setProtocolOptions(maxConnections=2)
    # note to self: if using putChild, the child must be bytes...
    reactor.listenTCP(50007, factory)
    reactor.run()

您将需要高速公路（您可以使用pip install autobahn安装它）

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