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WebSocket学习

客户端连接

客户端

<script>
    var socket = new WebSocket("ws://127.0.0.1:8000/chat");
</script>

服务端

import socket

sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
sock.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
sock.bind(('127.0.0.1', 8000))
sock.listen(5)

conn, address = sock.accept()
print('有链接过来。。。')
data = conn.recv(1024)
print(data)
"""
GET /chat HTTP/1.1

Host: 127.0.0.1:8000

Connection: Upgrade

Pragma: no-cache

Cache-Control: no-cache

Upgrade: websocket

Origin: http://localhost:63342

Sec-WebSocket-Version: 13

User-Agent: Mozilla/5.0 (Windows NT 6.1; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/64.0.3282.186 Safari/537.36

Accept-Encoding: gzip, deflate, br

Accept-Language: zh-CN,zh;q=0.9

Sec-WebSocket-Key: CyiOUMgm4Qd6WyjLQ+YbrA==

Sec-WebSocket-Extensions: permessage-deflate; client_max_window_bits


"""

conn.send("响应【握手】信息".encode('utf-8'))
conn.close()

浏览器发起了连接请求，其中包含了握手信息，服务端要想握手成功达成连接，需要满足下面几个条件：

　　- 首先获取客户端发来的 Sec-WebSocket-Key ，然后把这个值和 magic_string（258EAFA5-E914-47DA-95CA-C5AB0DC85B11）连接起来。

　　- 然后进行 SHA-1 hash 加密，最后再进行 base64 加密。

　　- 最后得到的值赋值给 Sec-WebSocket-Accept 字段当做响应头发给客户端。

响应头格式如下：

HTTP/1.1 101 Switching Protocols
Upgrade: websocket
Connection: Upgrade
Sec-WebSocket-Accept: s3pPLMBiTxaQ9kYGzzhZRbK+xOo=

建立连接（握手）

客户端

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>

    <button onclick="connection_check()">check</button>

<script>
    var socket = new WebSocket("ws://127.0.0.1:8000/chat");

    function connection_check() {
        if(0 == socket.readyState) {
            alert('尚未建立连接');
        }
        else if(1 == socket.readyState) {
            alert('连接已建立');
        }
        else if(2 == socket.readyState) {
            alert('连接正在进行关闭');
        }
        else {
            alert('连接已经关闭或者连接不能打开');
        }
    }


</script>

</body>
</html>

服务端

import socket
import hashlib
import base64


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


sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
sock.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
sock.bind(('127.0.0.1', 8000))
sock.listen(5)

while True:
    conn, address = sock.accept()
    print('有链接过来。。。')
    data = conn.recv(1024)

    headers = get_headers(data)
    magic_string = '258EAFA5-E914-47DA-95CA-C5AB0DC85B11'
    str_concatenate = headers['Sec-WebSocket-Key']+magic_string

    swa = base64.b64encode(hashlib.sha1(bytes(headers['Sec-WebSocket-Key']+magic_string,encoding='utf-8')).digest())
    response_tpl = "HTTP/1.1 101 Switching Protocols
" 
        "Upgrade:websocket
" 
        "Connection: Upgrade
" 
        "Sec-WebSocket-Accept: %s
" 
        "WebSocket-Location: ws://%s%s

"

    print(response_tpl)

    response = response_tpl %(swa.decode('utf-8'),headers['Host'],headers['url'])
    conn.send(bytes(response,encoding='utf-8'))

conn.close()

服务端解析客户端发的数据【解包】

客户端发来的 Frame Format

      0                   1                   2                   3
      0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
     +-+-+-+-+-------+-+-------------+-------------------------------+
     |F|R|R|R| opcode|M| Payload len |    Extended payload length    |
     |I|S|S|S|  (4)  |A|     (7)     |             (16/64)           |
     |N|V|V|V|       |S|             |   (if payload len==126/127)   |
     | |1|2|3|       |K|             |                               |
     +-+-+-+-+-------+-+-------------+ - - - - - - - - - - - - - - - +
     |     Extended payload length continued, if payload len == 127  |
     + - - - - - - - - - - - - - - - +-------------------------------+
     |                               |Masking-key, if MASK set to 1  |
     +-------------------------------+-------------------------------+
     | Masking-key (continued)       |          Payload Data         |
     +-------------------------------- - - - - - - - - - - - - - - - +
     :                     Payload Data continued ...                :
     + - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - +
     |                     Payload Data continued ...                |
     +---------------------------------------------------------------+

官方解释：

Client: FIN=1, opcode=0x1, msg="hello"
Server: (process complete message immediately) Hi.
Client: FIN=0, opcode=0x1, msg="and a"
Server: (listening, new message containing text started)
Client: FIN=0, opcode=0x0, msg="happy new"
Server: (listening, payload concatenated to previous message)
Client: FIN=1, opcode=0x0, msg="year!"
Server: (process complete message) Happy new year to you too!

客户端

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>

    <input type="text" id="input_msg">
    <button id="send_msg">发送消息</button>

<script>
    var socket = new WebSocket("ws://127.0.0.1:8000/chat");
    var send_btn = document.getElementById('send_msg');
    var input = document.getElementById('input_msg');
    send_btn.onclick = function() {
        console.log(input.value);
        if(1 == socket.readyState){
            socket.send(input.value);
            input.value = "";
        }else {
            alert('连接尚未建立');
        }
    }

</script>

</body>
</html>

服务端

import socket
import hashlib
import base64


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


sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
sock.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
sock.bind(('127.0.0.1', 8000))
sock.listen(5)

conn, address = sock.accept()
print('有链接过来。。。')
data = conn.recv(1024)

headers = get_headers(data)
magic_string = '258EAFA5-E914-47DA-95CA-C5AB0DC85B11'
str_concatenate = headers['Sec-WebSocket-Key']+magic_string

swa = base64.b64encode(hashlib.sha1(bytes(headers['Sec-WebSocket-Key']+magic_string,encoding='utf-8')).digest())
response_tpl = "HTTP/1.1 101 Switching Protocols
" 
    "Upgrade:websocket
" 
    "Connection: Upgrade
" 
    "Sec-WebSocket-Accept: %s
" 
    "WebSocket-Location: ws://%s%s

"

response = response_tpl %(swa.decode('utf-8'),headers['Host'],headers['url'])
conn.send(bytes(response,encoding='utf-8'))

while True:
    info = conn.recv(8096)
    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')
    body = bytes_list.decode('utf-8')
    print(body)


conn.close()

服务端给客户端发送数据【封包】

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"  # 即 10000001，FIN置为1，opcode置为0x1
    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

服务端封包的时候不需要加密，即没有 MASK 字段。

但是需要注意length的判断和字节序的问题。

基于Python简单实现的WebSocket示例

服务端：

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"    # 即 10000001，FIN置为1，opcode置为0x1
    length = len(msg_bytes)
    if length < 126:
        token += struct.pack("B", length)
    elif length <= 0xFFFF:
        # Read the next 16 bits and interpret those as an unsigned integer.
        token += struct.pack("!BH", 126, length)
    else:
        # Read the next 64 bits and interpret those as an unsigned integer.
        token += struct.pack("!BQ", 127, length)

    msg = token + msg_bytes
    conn.send(msg)
    return True

def get_conn(ip='127.0.0.1',port=80):
    """
    准备接收客户端的请求并建立连接
    :param ip: 绑定的ip
    :param port: 监听的端口
    :return: 
    """
    sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
    sock.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
    sock.bind((ip, port))
    sock.listen(5)

    conn, address = sock.accept()
    print("有连接到来...")
    data = conn.recv(1024)
    headers = get_headers(data)
    magic_string = '258EAFA5-E914-47DA-95CA-C5AB0DC85B11'
    str_completed = headers['Sec-WebSocket-Key'] + magic_string

    swa = base64.b64encode(hashlib.sha1(bytes(str_completed, encoding='utf-8')).digest())
    response_tpl = "HTTP/1.1 101 Switching Protocols
" 
                   "Upgrade:websocket
" 
                   "Connection: Upgrade
" 
                   "Sec-WebSocket-Accept: %s
" 
                   "WebSocket-Location: ws://%s%s

"

    response = response_tpl % (swa.decode('utf-8'), headers['Host'], headers['url'])
    conn.send(bytes(response, encoding='utf-8'))
    return sock,conn

def close(sock):
    """
    关闭sock连接
    :param sock: 
    :return: 
    """
    sock.close()

def run():
    """
    消息循环
    :return: 
    """
    sock,conn = get_conn()

    while True:
        try:
            info = conn.recv(8096)
        except Exception as e:
            info = None
        if not info:
            break
        # 位运算得到第二个字节后7个bit的值
        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()
        # DECODED
        for i in range(len(decoded)):
            chunk = decoded[i] ^ mask[i % 4]
            bytes_list.append(chunk)
        body = str(bytes_list, encoding='utf-8')
        print("Client: %s" % body)
        send_msg(conn, ("服务端已收到: %s" % body).encode('utf-8'))

    close(sock)


if __name__ == '__main__':
    run()

客户端：

<!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://127.0.0.1:80/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框架实现Web聊天室

示例来自：http://www.cnblogs.com/wupeiqi/articles/6558766.html

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()

index.html

<!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>

参考：http://www.cnblogs.com/wupeiqi/articles/6558766.html

参考：https://developer.mozilla.org/en-US/docs/Web/API/WebSockets_API/Writing_WebSocket_servers

RFC 6455：https://tools.ietf.org/html/rfc6455

WebSocket+Flask实现的实时投票和实时通知示例

'''
pip install gevent-websocket
'''

from flask import Flask,render_template,request,session,redirect,jsonify
import uuid
from geventwebsocket.handler import WebSocketHandler
from gevent.pywsgi import WSGIServer
import json


app = Flask(__name__)
app.secret_key = 'wnclwespcqwlkjaytcw'

USERS = {
    '1':{'name':'小明','count':0},
    '2':{'name':'小强','count':0},
    '3':{'name':'小刚','count':0},
}


@app.before_request
def before_request():
    allow_url = ['login','notify']
    if request.endpoint in allow_url:
        return None
    user_info = session.get('user_info')
    if user_info:
        return None
    return redirect('/login')


@app.route('/login',methods=['GET','POST'])
def login():
    if request.method == "GET":
        return render_template('login.html')
    else:
        uid = str(uuid.uuid4())
        session['user_info'] = {'id':uid,'name':request.form.get('user')}
        return redirect('/index')


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


# 用来保存全部WS链接
WS_DICT = {}


@app.route('/notify')
def notify():
    data = {'msg': '有新工单到来，请及时处理！', 'type': 'notify'}

    for k, v in WS_DICT.items():
        # 3. 向全部存活的客户端推送消息
        v.send(json.dumps(data))


    return "消息已推送"


@app.route('/message')
def message():
    if request.environ.get('wsgi.websocket'):
        # 根据 'wsgi.websocket' 这个字段是否为空来判断来源是 websocket 还是 http
        ws = request.environ['wsgi.websocket']
        if not ws:
            return "请使用WebSocket协议"
        # 1. 刚连接成功
        uid = session.get('user_info').get('id')
        WS_DICT[uid] = ws

        print('有连接到来, Name: %s from: %s' % (session['user_info'],ws))
        print(WS_DICT)


        from geventwebsocket.websocket import WebSocket
        while True:
            # 2. 等待用户发送消息，并接受
            message = ws.receive()
            # 如果客户端关闭浏览器，那么就会收到一个None，即 message=None
            if not message:
                del WS_DICT[uid]
                break

            old = USERS[message]['count']
            new = old + 1
            USERS[message]['count'] = new

            data = {'user':message,'count':new,'type':'vote'}

            for k,v in WS_DICT.items():
                # 3. 向全部存活的客户端推送消息
                v.send(json.dumps(data))

    return "Connected!"

if __name__ == '__main__':
    http_server = WSGIServer(('127.0.0.1', 8000), app, handler_class=WebSocketHandler)
    http_server.serve_forever()

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>
<form method="post" novalidate>
    <input type="text" name="user">
    <input type="submit" value="提交">
</form>
</body>
</html>

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>
    <h1>基于WebSocket+Flask的投票系统</h1>
    <a onclick="closeConn();" href="#">关闭连接</a>

    <!--
        <a onclick="createConn();" href="">创建连接</a>
        这样写会导致无法保持websocket连接
    -->

    <a onclick="createConn();" href="#">创建连接</a>
    <ul>
        {% for k,v in users.items() %}
            <li style="cursor:pointer;" id="user_{{k}}" ondblclick="vote('{{k}}')">{{v.name}} <span>{{v.count}}</span> </li>
        {% endfor %}

    </ul>

    <script src="{{ url_for('static',filename='jquery-3.3.1.min.js')}}"></script>
    <script>

        var socket = null;

        function socketInit() {
            socket.onopen = function () {
                /* 与服务器端连接成功后，自动执行 */
                alert('与服务器端握手成功，可以开始投票。');
            };

            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); // {'user':1,'count':new,'type':'vote'}
                if('vote' == response['type'])
                {
                    var nid = '#user_' + response.user;
                    $(nid).find('span').text(response.count);
                }
                else if('notify' == response['type'])
                {
                    alert(response['msg']);
                }

            };

            socket.onclose = function (event) {
                /* 服务器端主动断开连接时，自动执行 */
                alert('服务器端已经断开WebSocket链接。');
            };

        }
        function vote(id) {
            if(socket != null)
            {
                socket.send(id);
            }
            else
            {
                alert('请先建立WebSocket链接');
            }
        }
        function closeConn() {
            socket.close()
        }
        function createConn() {
            socket = new WebSocket("ws://127.0.0.1:8000/message");
            socketInit();
        }
    </script>
</body>
</html>

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原文地址：https://www.cnblogs.com/standby/p/8595588.html