WebSocket

websocket原理

1、服务端运行，等待客户端连接
2、某某来连接，服务端同意
3、某某立即发送一个握手信息

b'GET /xxxx HTTP/1.1\r\n
Host: 127.0.0.1:8002\r\n
Connection: Upgrade\r\n
Pragma: no-cache\r\n
Cache-Control: no-cache\r\n
Upgrade: websocket\r\n
Origin: http://localhost:63342\r\n
Sec-WebSocket-Version: 13\r\n
User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/73.0.3683.86 Safari/537.36\r\n
Accept-Encoding: gzip, deflate, br\r\n
Accept-Language: zh-CN,zh;q=0.9\r\n
Cookie: Hm_lvt_d214947968792b839fd669a4decaaffc=1550556279\r\n
Sec-WebSocket-Key: MdPqInjP3oSeusycSwAPRg==\r\n
Sec-WebSocket-Extensions: permessage-deflate; client_max_window_bits\r\n
\r\n'

4、服务端接收握手信息后需要对数据进行加密
-- 'MdPqInjP3oSeusycSwAPRg==' + '258EAFA5-E914-47DA-95CA-C5AB0DC85B11'
-- sha1加密
-- base64加密
-- 加密后返回结果给客户端

response_tpl = "HTTP/1.1 101 Switching Protocols\r\n" \
"Upgrade:websocket\r\n" \
"Connection: Upgrade\r\n" \
"Sec-WebSocket-Accept: %s\r\n" \
"WebSocket-Location: ws://%s%s\r\n\r\n"
response_str = response_tpl % (ac.decode('utf-8'), headers['Host'], headers['url'])
conn.send(bytes(response_str, encoding='utf-8'))

5、双方进行通信
　　a、客户端给服务端发消息
　　     读取第二个字节的后7位
　　　 127：10(头部),4(MASK KEY),数据包
　　　 126：4(头部),4(MASK KEY),数据包
　　　 125：2(头部),4(MASK KEY),数据包
　　b、服务端给客户端发送消息

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
    

基于Python实现简单示例

 服务端：server.py

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')

    # for i in data.split('\r\n'):
    #     print(i)
    header, body = data.split('\r\n\r\n', 1)
    header_list = header.split('\r\n')
    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)
# 1、等待客户连接
conn, address = sock.accept()
# 2、接收验证消息
'''
    b'GET /xxxx HTTP/1.1\r\n
    Host: 127.0.0.1:8002\r\n
    Connection: Upgrade\r\n
    Pragma: no-cache\r\n
    Cache-Control: no-cache\r\n
    Upgrade: websocket\r\n
    Origin: http://localhost:63342\r\n
    Sec-WebSocket-Version: 13\r\n
    User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/73.0.3683.86 Safari/537.36\r\n
    Accept-Encoding: gzip, deflate, br\r\n
    Accept-Language: zh-CN,zh;q=0.9\r\n
    Cookie: Hm_lvt_d214947968792b839fd669a4decaaffc=1550556279\r\n
    Sec-WebSocket-Key: MdPqInjP3oSeusycSwAPRg==\r\n
    Sec-WebSocket-Extensions: permessage-deflate; client_max_window_bits\r\n
    \r\n'
'''
data = conn.recv(8096)
headers = get_headers(data)
# 3、对数据进行加密
magic_string = '258EAFA5-E914-47DA-95CA-C5AB0DC85B11' # 固定加密值
value = headers['Sec-WebSocket-Key'] + magic_string # 最终加密值
ac = base64.b64encode(hashlib.sha1(value.encode('utf-8')).digest()) # 固定加密算法
# 4、将加密后的值返回给客户端
response_tpl = "HTTP/1.1 101 Switching Protocols\r\n" \
      "Upgrade:websocket\r\n" \
      "Connection: Upgrade\r\n" \
      "Sec-WebSocket-Accept: %s\r\n" \
      "WebSocket-Location: ws://%s%s\r\n\r\n"
response_str = response_tpl % (ac.decode('utf-8'), headers['Host'], headers['url'])
conn.send(bytes(response_str, encoding='utf-8'))
# 5、接收客户端发送的消息
while True:
    # 获取客户端发送的数据【解包】
    try:
        info = conn.recv(8096)
    except Exception as e:
        info = None
    if not info:
        break
    payload_len = info[1] & 127
    if payload_len == 126:
        extend_payload_len = info[2:4]
        mask = info[4:8]
        decoded = info[8:]
    elif payload_len == 127:
        extend_payload_len = info[2:10]
        mask = info[10:14]
        decoded = info[14:]
    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')
    # 向客户端发送数据【封包】
    send_msg(conn, body.encode('utf-8'))

sock.close()

客户端：client.html

<!DOCTYPE html>
<html>
<head lang="en">
    <meta charset="UTF-8">
    <title></title>
</head>
<body>
    <div>
        <input type="text" id="txt"/>
        <input type="button" id="btn" value="提交" onclick="sendMsg();"/>
        <input type="button" id="close" value="关闭连接" onclick="closeConn();"/>
    </div>
    <div id="content"></div>
 
<script type="text/javascript">
    var socket = new WebSocket("ws://127.0.0.1:8002/xxxx");
 
    socket.onopen = function () {
        /* 与服务器端连接成功后，自动执行 */
 
        var newTag = document.createElement('div');
        newTag.innerHTML = "【连接成功】";
        document.getElementById('content').appendChild(newTag);
    };
 
    socket.onmessage = function (event) {
        /* 服务器端向客户端发送数据时，自动执行 */
        var response = event.data;
        var newTag = document.createElement('div');
        newTag.innerHTML = response;
        document.getElementById('content').appendChild(newTag);
    };
 
    socket.onclose = function (event) {
        /* 服务器端主动断开连接时，自动执行 */
        var newTag = document.createElement('div');
        newTag.innerHTML = "【关闭连接】";
        document.getElementById('content').appendChild(newTag);
    };
 
    function sendMsg() {
        var txt = document.getElementById('txt');
        socket.send(txt.value);
        txt.value = "";
    }
    function closeConn() {
        socket.close();
        var newTag = document.createElement('div');
        newTag.innerHTML = "【关闭连接】";
        document.getElementById('content').appendChild(newTag);
    }
 
</script>
</body>
</html>

基于flask的示例

主要有两个文件：1、服务端（flask_websoket.py）2、客户端（index.html）

服务端：flask_websoket.py

from flask import Flask,render_template,request
from geventwebsocket.handler import WebSocketHandler
from gevent.pywsgi import WSGIServer
import json

app = Flask(__name__)

# 用户数据
USER_DIC = {
    '1':{'name':'大哥','count':0},
    '2':{'name':'二哥','count':0},
    '3':{'name':'小弟','count':0},
}

# websocket连接池
WEBSOCKET_LIST = []

@app.route('/')
def index():
    return render_template('index.html',userdic = USER_DIC)

@app.route('/message')
def message():
    ws = request.environ.get('wsgi.websocket')
    if not ws:
        print('http')
        return 'HTTP协议'
    # 把每个人的连接存起来
    WEBSOCKET_LIST.append(ws)
    while True:
        # 等待用户发送消息并接收
        uid = ws.receive()
        # 如果关闭了连接
        if not uid:
            # 移除连接
            WEBSOCKET_LIST.remove(ws)
            # 关闭连接
            ws.close()
            # 跳出循环
            break
        old_count = USER_DIC[uid]['count']
        new_count = old_count + 1
        USER_DIC[uid]['count'] = new_count
        # 给所有用户返回最新数据
        for client in WEBSOCKET_LIST:
            client.send(json.dumps({'uid':uid,'count':new_count}))

    return 'ok'

if __name__ == '__main__':
    http_server = WSGIServer(('127.0.0.1',5000),app,handler_class=WebSocketHandler)
    http_server.serve_forever()

客户端：index.html

<!DOCTYPE html>
<html>
<head lang="en">
    <meta charset="UTF-8">
    <title></title>
</head>
<body>
    <h1>投票系统</h1>
    <div>
        <ul>
            {% for k,v in userdic.items()%}
                <li onclick="goodfive({{ k }})" id = uid_{{ k }}>{{ v.name }}<span>{{ v.count }}</span></li>
            {% endfor %}
            
        </ul>
    </div>

    <script src="{{ url_for('static',filename='js/jquery-3.1.1.js')}}"></script>
    <script type="text/javascript">
        var socket = new WebSocket("ws://127.0.0.1:5000/message");

        socket.onmessage = function (event) {
            /* 服务器端向客户端发送数据时，自动执行 */
            var response = JSON.parse(event.data);
            $('#'+'uid_'+response.uid).find('span').text(response.count);
        };

        socket.onclose = function (event) {
            /* 服务器端主动断开连接时，自动执行 */
            console.log('关闭连接');
        };

        function goodfive(uid) {
            socket.send(uid)
        }

    </script>
</body>
</html>

<!DOCTYPE html>
<html>
<head lang="en">
    <meta charset="UTF-8">
    <title></title>
</head>
<body>
    <div>
        <input type="text" id="txt"/>
        <input type="button" id="btn" value="提交" onclick="sendMsg();"/>
        <input type="button" id="close" value="关闭连接" onclick="closeConn();"/>
    </div>
    <div id="content"></div>
 
<script type="text/javascript">
    var socket = new WebSocket("ws://127.0.0.1:8003/chatsocket");
 
    socket.onopen = function () {
        /* 与服务器端连接成功后，自动执行 */
 
        var newTag = document.createElement('div');
        newTag.innerHTML = "【连接成功】";
        document.getElementById('content').appendChild(newTag);
    };
 
    socket.onmessage = function (event) {
        /* 服务器端向客户端发送数据时，自动执行 */
        var response = event.data;
        var newTag = document.createElement('div');
        newTag.innerHTML = response;
        document.getElementById('content').appendChild(newTag);
    };
 
    socket.onclose = function (event) {
        /* 服务器端主动断开连接时，自动执行 */
        var newTag = document.createElement('div');
        newTag.innerHTML = "【关闭连接】";
        document.getElementById('content').appendChild(newTag);
    };
 
    function sendMsg() {
        var txt = document.getElementById('txt');
        socket.send(txt.value);
        txt.value = "";
    }
    function closeConn() {
        socket.close();
        var newTag = document.createElement('div');
        newTag.innerHTML = "【关闭连接】";
        document.getElementById('content').appendChild(newTag);
    }
 
</script>
</body>
</html>

基于Tornado实现的聊天室示例

#!/usr/bin/env python
# -*- coding:utf-8 -*-
import uuid
import json
import tornado.ioloop
import tornado.web
import tornado.websocket


class IndexHandler(tornado.web.RequestHandler):
    def get(self):
        self.render('index.html')


class ChatHandler(tornado.websocket.WebSocketHandler):
    # 用户存储当前聊天室用户
    waiters = set()
    # 用于存储历时消息
    messages = []

    def open(self):
        """
        客户端连接成功时，自动执行
        :return: 
        """
        ChatHandler.waiters.add(self)
        uid = str(uuid.uuid4())
        self.write_message(uid)

        for msg in ChatHandler.messages:
            content = self.render_string('message.html', **msg)
            self.write_message(content)

    def on_message(self, message):
        """
        客户端连发送消息时，自动执行
        :param message: 
        :return: 
        """
        msg = json.loads(message)
        ChatHandler.messages.append(message)

        for client in ChatHandler.waiters:
            content = client.render_string('message.html', **msg)
            client.write_message(content)

    def on_close(self):
        """
        客户端关闭连接时，，自动执行
        :return: 
        """
        ChatHandler.waiters.remove(self)


def run():
    settings = {
        'template_path': 'templates',
        'static_path': 'static',
    }
    application = tornado.web.Application([
        (r"/", IndexHandler),
        (r"/chat", ChatHandler),
    ], **settings)
    application.listen(8888)
    tornado.ioloop.IOLoop.instance().start()


if __name__ == "__main__":
    run()

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Python聊天室</title>
</head>
<body>
    <div>
        <input type="text" id="txt"/>
        <input type="button" id="btn" value="提交" onclick="sendMsg();"/>
        <input type="button" id="close" value="关闭连接" onclick="closeConn();"/>
    </div>
    <div id="container" style="border: 1px solid #dddddd;margin: 20px;min-height: 500px;">

    </div>

    <script src="/static/jquery-2.1.4.min.js"></script>
    <script type="text/javascript">
        $(function () {
            wsUpdater.start();
        });

        var wsUpdater = {
            socket: null,
            uid: null,
            start: function() {
                var url = "ws://127.0.0.1:8888/chat";
                wsUpdater.socket = new WebSocket(url);
                wsUpdater.socket.onmessage = function(event) {
                    console.log(event);
                    if(wsUpdater.uid){
                        wsUpdater.showMessage(event.data);
                    }else{
                        wsUpdater.uid = event.data;
                    }
                }
            },
            showMessage: function(content) {
                $('#container').append(content);
            }
        };

        function sendMsg() {
            var msg = {
                uid: wsUpdater.uid,
                message: $("#txt").val()
            };
            wsUpdater.socket.send(JSON.stringify(msg));
        }

</script>

</body>
</html>