WebSocket协议是基于TCP的一种新的协议。WebSocket最初在HTML5规范中被引用为TCP连接，作为基于TCP的套接字API的占位符。它实现了浏览器与服务器全双工(full-duplex)通信。其本质是保持TCP连接，在浏览器和服务端通过Socket进行通信。
1，启动服务端
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‘, 8002)) sock.listen(5) # 等待用户连接 conn, address = sock.accept() ... ... ...
启动Socket服务器后，等待用户【连接】，然后进行收发数据。
2，浏览器(客户端)连接
<script type="text/javascript"> var socket = new WebSocket("ws://127.0.0.1:8002/xxoo"); ... </script>
当客户端向服务端发送连接请求时，不仅连接还会发送【握手】信息，并等待服务端响应，至此连接才创建成功！
3，建立连接（握手）
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‘, 8002)) sock.listen(5) # 获取客户端socket对象 conn, address = sock.accept() # 获取客户端的【握手】信息 data = conn.recv(1024) ... ... ... conn.send(‘响应【握手】信息‘)
请求和响应的【握手】信息需要遵循规则：
- 从请求【握手】信息中提取 Sec-WebSocket-Key
- 利用magic_string 和 Sec-WebSocket-Key 进行hmac1加密，再进行base64加密
- 将加密结果响应给客户端
注：magic string为：258EAFA5-E914-47DA-95CA-C5AB0DC85B11
请求【握手】信息为：
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GET /chatsocket HTTP/1.1Host: 127.0.0.1:8002Connection: UpgradePragma: no-cacheCache-Control: no-cacheUpgrade: websocketOrigin: http://localhost:63342Sec-WebSocket-Version: 13Sec-WebSocket-Key: mnwFxiOlctXFN/DeMt1Amg==Sec-WebSocket-Extensions: permessage-deflate; client_max_window_bits...... |
提取Sec-WebSocket-Key值并加密：
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import socketimport base64import 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 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) conn, address = sock.accept()data = conn.recv(1024)headers = get_headers(data) # 提取请求头信息# 对请求头中的sec-websocket-key进行加密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"magic_string = ‘258EAFA5-E914-47DA-95CA-C5AB0DC85B11‘value = headers[‘Sec-WebSocket-Key‘] + magic_stringac = base64.b64encode(hashlib.sha1(value.encode(‘utf-8‘)).digest())response_str = response_tpl % (ac.decode(‘utf-8‘), headers[‘Host‘], headers[‘url‘])# 响应【握手】信息conn.send(bytes(response_str, encoding=‘utf-8‘))......... |
4，客户端与服务端收发数据
客户端和服务端传输数据时，需要对数据进行【封包】和【解包】。客户端的JavaScript类库已经封装【封包】和【解包】过程，但Socket服务端需要手动实现。
第一步：获取客户端发送的数据【解包】
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‘) print(body)
解包详细过程：
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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 ... |+---------------------------------------------------------------+ |
第二步：向客户端发送数据【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" 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
5，基于Python实现简单示例
a. 基于Python socket实现的WebSocket服务端：
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#!/usr/bin/env python# -*- coding:utf-8 -*-import socketimport base64import 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(‘\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 def run(): sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM) sock.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1) sock.bind((‘127.0.0.1‘, 8003)) sock.listen(5) conn, address = sock.accept() data = conn.recv(1024) headers = get_headers(data) 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" value = headers[‘Sec-WebSocket-Key‘] + ‘258EAFA5-E914-47DA-95CA-C5AB0DC85B11‘ ac = base64.b64encode(hashlib.sha1(value.encode(‘utf-8‘)).digest()) response_str = response_tpl % (ac.decode(‘utf-8‘), headers[‘Host‘], headers[‘url‘]) conn.send(bytes(response_str, encoding=‘utf-8‘)) while True: 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‘) send_msg(conn,body.encode(‘utf-8‘)) sock.close() if __name__ == ‘__main__‘: run() |
b. 利用JavaScript类库实现客户端
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<!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> |
c.更多
名称 类型 描述 # WebSocket 对象 提供到远程主机的双向通道。 # close 方法 关闭websocket。 # send 方法 使用websocket 发送数据到服务器。 # binaryType 属性 由 onmessage 接收的二进制数据格式。 # bufferedAmount 属性 使用 send 的已排队的数据字节数。 # extensions 属性 报告服务器所选中的扩展名。 # onclose 属性 当套接字关闭时调用的事件处理程序。 # onerror 属性 当出现错误时调用的事件处理程序。 # onmessage 属性 通知接收到消息的事件处理程序。 # onopen 属性 当 websocket 已连接时调用的事件处理程序。 # protocol 属性 报告服务器所选中的协议。 # readyState 属性 报告 websocket 连接的状态。 # url 属性 报告套接字的当前 URL。
7，基于Tornado实现Web聊天室
更新中...
