实现投票功能
后端: import json from flask import Flask, render_template, request from geventwebsocket.handler import WebSocketHandler from gevent.pywsgi import WSGIServer app = Flask(__name__) USERS = { '1': {'name': 'alex', 'count': 0}, '2': {'name': 'lex', 'count': 0}, '3': {'name': 'ex', 'count': 0}, } @app.route('/index') def index(): return render_template('index.html', users=USERS) WebSocket_List = [] @app.route('/message') def message(): ws = request.environ.get('wsgi.websocket') if not ws: print('http') return '你使用的是http协议' WebSocket_List.append(ws) while True: # 等待用户发送的消息，并接收 cid = ws.receive() if not cid: WebSocket_List.remove(ws) ws.close() break old = USERS[cid]['count'] new = old + 1 USERS[cid]['count'] = new for client in WebSocket_List: client.send(json.dumps({'cid': cid, 'count': new})) if __name__ == '__main__': http_server = WSGIServer(('127.0.0.1', 5000), app, handler_class=WebSocketHandler) http_server.serve_forever()
前端:index.html： <!DOCTYPE html> <html lang="zh-CN"> <head> <meta charset="UTF-8"> <title>Title</title> <meta name="viewport" content="width=device-width, initial-scale=1"> </head> <body> <h1>投票系统</h1> <ul> {% for k,v in users.items() %} <li onclick="vote({{k}})" id="id_{{k}}">{{v.name}} <span>{{v.count}}</span></li> {% endfor %} </ul> <script src="../static/jquery.js"></script> <script> var ws = new WebSocket('ws://127.0.0.1:5000/message'); // ws.send('你好') ws.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 res = JSON.parse(event.data); $('#id_'+res.cid).find('span').text(res.count); console.log(res) }; function vote(cid){ ws.send(cid) } </script> </body> </html>
手动通过socket创建web-socket：
后端： 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 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) # 1. 等待用户连接 conn, address = sock.accept() print('人来了') # 2. 接收验证信息 msg = conn.recv(8096) msg_dict = get_headers(msg) # 3. 对数据加密 magic_string = '258EAFA5-E914-47DA-95CA-C5AB0DC85B11' value = msg_dict['Sec-WebSocket-Key'] + magic_string ac = base64.b64encode(hashlib.sha1(value.encode('utf-8')).digest()) # 4. 将加密结果返回 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://127.0.0.1:8002/xxx\r\n\r\n" response_str = response_tpl % (ac.decode('utf-8'),) conn.send(bytes(response_str, encoding='utf-8')) # 5. 接收数据 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') print(body) # 发送数据 send_msg(conn, body.encode('utf-8')) 前端： <!DOCTYPE html> <html lang="zh-CN"> <head> <meta charset="UTF-8"> <title>Title</title> <meta name="viewport" content="width=device-width, initial-scale=1"> </head> <body> <script> var ws = new WebSocket("ws://127.0.0.1:8002/xxx"); // 手动先发数据 // 服务器端向客户端发送数据时，自动执行 ws.onmessage=function (event) { var response = event.data; console.log(response) } </script> </body> </html>
1. 服务端运行，等待客户端连接 2. 客户端连接，服务端同意 3. 客户端立即发送一个'握手信息' * GET /xxx HTTP/1.1 Host: 127.0.0.1:8002 Connection: Upgrade Pragma: no-cache Cache-Control: no-cache User-Agent: Mozilla/5.0 (Windows NT 6.3; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/80.0.3987.100 Safari/537.36 Upgrade: websocket Origin: http://localhost:63342 Sec-WebSocket-Version: 13 Accept-Encoding: gzip, deflate, br Accept-Language: zh-CN,zh;q=0.9,en;q=0.8 Sec-WebSocket-Key: uwHQyTgKG3ybh2DNUEYbog== # 重点 Sec-WebSocket-Extensions: permessage-deflate; client_max_window_bits 4. 服务端接收握手信息后需要对数据进行加密 - uwHQyTgKG3ybh2DNUEYbog== + '258EAFA5-E914-47DA-95CA-C5AB0DC85B11' - sha1 - base64 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://127.0.0.1:8002/xxx\r\n\r\n" 双方就可以进行互相通信 5. 客户端给服务端发送信息 读取第二个字节的后7位 127: 10,4,数据 126: 4,4,数据 <=125: 2,4,数据 6. 服务端给客户端发送信息 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)
1. 什么是websocket？ 是一套协议，协议规定了： - 连接时需要握手 - 发送数据进行加密 - 连接之后要断开 2. websocket的意义 3. websocket的兼容性是他的缺点 4. 哪些框架支持websocket - flask， gevent-websocket - django， channel - torando框架自带 5. 应用场景 实时响应式时，可以使用websocket