• websocket协议


    什么是websocket协议

    websocket协议类似于http协议

    http   :数据按 分割,请求头和请求体按  分割  是短连接、无状态基于tcp协议

    websocket:数据按 分割,创建连接后不断开,创建连接是需要先验证,发送数据时要加密

    websocket本质

    1、创建一个建立连接之后不断开的socket

    2、创建连接(握手)

      -客户端向服务端发送请求

      -服务端获取请求头中的Sec-WebSocket-key的值,将此值+magic_string(魔法字符串)进行hashlib和base64加密

      -构造响应头,里面包含Sec-WebSocket-Accept: 加密后的值

      -返送给客户端

      -客户端再拿到加密的数据,解密进行验证

    3、连接建立成功后:建立双工通道(同一时间,即可发送数据也可接受数据),进行数据通信

      -发送的数据都是加密的,解密后,根据payload_len的值获取内容(payload_len的值相当于报头)

        -payload_len <=125

        -payload_len ==126

        -payload_len ==127

      -将获取的内容分为

        -mask_key

        -数据

        根据mask_key和数据进行位运算,最后解析出数据

      

    示例:

    参考:http://www.cnblogs.com/wupeiqi/p/6558766.html
    import socket
    import base64
    import hashlib
    
    def get_headers(data):
        """
        将请求头格式化成字典
        :param data:
        :return:
        """
        header_dict = {}
        data = str(data, encoding='utf-8')
        header, body = data.split('
    
    ', 1)
        header_list = header.split('
    ')
        for i in range(0, len(header_list)):
            if i == 0:
                if len(header_list[i].split(' ')) == 3:
                    header_dict['method'], header_dict['url'], header_dict['protocol'] = header_list[i].split(' ')
            else:
                k, v = header_list[i].split(':', 1)
                header_dict[k] = v.strip()
        return header_dict
    
    def send_msg(conn, msg_bytes):
        """
        WebSocket服务端向客户端发送消息
        :param conn: 客户端连接到服务器端的socket对象,即: conn,address = socket.accept()
        :param msg_bytes: 向客户端发送的字节
        :return:
        """
        import struct
    
        token = b"x81"
        length = len(msg_bytes)
        if length < 126:
            token += struct.pack("B", length)
        elif length <= 0xFFFF:
            token += struct.pack("!BH", 126, length)
        else:
            token += struct.pack("!BQ", 127, length)
    
        msg = token + msg_bytes
        conn.send(msg)
        return True
    
    sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
    sock.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
    sock.bind(('127.0.0.1', 8002))
    sock.listen(5)
    # 等待用户连接
    conn, address = sock.accept()
    
    data = conn.recv(8096)
    
    header_dict = get_headers(data)
    # 在验证环节对Sec-WebSocket-Key对应的值进行加密
    
    magic_string = '258EAFA5-E914-47DA-95CA-C5AB0DC85B11'
    value = header_dict['Sec-WebSocket-Key'] + magic_string
    ac = base64.b64encode(hashlib.sha1(value.encode('utf-8')).digest())
    
    
    # 构造响应头
    response_tpl = "HTTP/1.1 101 Switching Protocols
    " 
          "Upgrade:websocket
    " 
          "Connection: Upgrade
    " 
          "Sec-WebSocket-Accept: %s
    " 
          "WebSocket-Location: ws://127.0.0.1:8002
    
    "
    
    response = response_tpl %(str(ac,encoding='utf-8'),)
    
    conn.sendall(bytes(response,encoding='utf-8'))
    
    
    while True:
        # 用户发过来的加密的数据
        info = conn.recv(8096)
        payload_len = info[1] & 127
        if payload_len == 127:
            extend_payload_len = info[2:10]
            mask = info[10:14]
            decoded = info[14:]
        elif payload_len == 126:
            extend_payload_len = info[2:4]
            mask = info[4:8]
            decoded = info[8:]
        else:
            extend_payload_len = None
            mask = info[2:6]
            decoded = info[6:]
    
        bytes_list = bytearray()
        for i in range(len(decoded)):
            chunk = decoded[i] ^ mask[i % 4]
            bytes_list.append(chunk)
        body = str(bytes_list, encoding='utf-8')
        print(body)
    
        body = body + 'sb'
    
        send_msg(conn,bytes(body,encoding='utf-8'))
    app.py
    <!DOCTYPE html>
    <html lang="zh-cn">
    <head>
        <meta charset="UTF-8">
        <meta http-equiv="X-UA-Compatible" content="IE=edge">
        <meta name="viewport" content="width=device-width, initial-scale=1">
        <title>Title</title>
        <style>
            .msg-item{
                padding: 5px;
                border: 1px;
                margin: 0 5px;
            }
        </style>
    </head>
    <body>
        <h1>首页</h1>
        <div>
            <h2>发送消息</h2>
            <input id="msg" type="text"  /> <input type="button" value="发送" onclick="sendMsg()">
            <h2>接收消息</h2>
            <div id="container">
    
            </div>
        </div>
    
        <script src="/static/jquery-3.3.1.min.js"></script>
        <script>
    
            ws = new WebSocket('ws://192.168.12.42:5000/test');
            ws.onmessage = function (event) {
                var tag = document.createElement('div');
                tag.className = 'msg-item';
                tag.innerText = event.data;
                $('#container').append(tag);
            }
    
            function sendMsg() {
                ws.send($('#msg').val());
            }
        </script>
    </body>
    </html>
    index.html

    待续.....

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  • 原文地址:https://www.cnblogs.com/caochao-/p/9053069.html
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