websocket 工作原理

import socket, base64, hashlibsock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)sock.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)sock.bind((‘127.0.0.1‘, 9527))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)print(data)"""b‘GET /ws HTTP/1.1\r\nHost: 127.0.0.1:9527\r\nUser-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:62.0) Gecko/20100101 Firefox/62.0\r\nAccept: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8\r\nAccept-Language: zh-CN,zh;q=0.8,zh-TW;q=0.7,zh-HK;q=0.5,en-US;q=0.3,en;q=0.2\r\nAccept-Encoding: gzip, deflate\r\nSec-WebSocket-Version: 13\r\nOrigin: http://localhost:63342\r\nSec-WebSocket-Extensions: permessage-deflate\r\nSec-WebSocket-Key: jocLOLLq1BQWp0aZgEWL5A==\r\nCookie: session=6f2bab18-2dc4-426a-8f06-de22909b967b\r\nConnection: keep-alive, Upgrade\r\nPragma: no-cache\r\nCache-Control: no-cache\r\nUpgrade: websocket\r\n\r\n‘"""# magic string为：258EAFA5-E914-47DA-95CA-C5AB0DC85B11magic_string = ‘258EAFA5-E914-47DA-95CA-C5AB0DC85B11‘def get_headers(data): ???header_dict = {} ???header_str = data.decode("utf8") ???for i in header_str.split("\r\n"): ???????if str(i).startswith("Sec-WebSocket-Key"): ???????????header_dict["Sec-WebSocket-Key"] = i.split(":")[1].strip() ???return header_dictdef get_header(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_dictheaders = 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://127.0.0.1:9527\r\n\r\n"value = headers[‘Sec-WebSocket-Key‘] + magic_stringprint(value)ac = base64.b64encode(hashlib.sha1(value.encode(‘utf-8‘)).digest())response_str = response_tpl % (ac.decode(‘utf-8‘))# 响应【握手】信息conn.send(response_str.encode("utf8"))while True: ???msg = conn.recv(8096) ???print(msg)

# b‘\x81\x83\xceH\xb6\x85\xffz\x85‘hashstr = b‘\x81\x83\xceH\xb6\x85\xffz\x85‘# b‘\x81 ???\x83 ???\xceH\xb6\x85\xffz\x85‘# 将第二个字节也就是 \x83 第9-16位 进行与127进行位运算payload = hashstr[1] & 127print(payload)if payload == 127: ???extend_payload_len = hashstr[2:10] ???mask = hashstr[10:14] ???decoded = hashstr[14:]# 当位运算结果等于127时,则第3-10个字节为数据长度# 第11-14字节为mask 解密所需字符串# 则数据为第15字节至结尾if payload == 126: ???extend_payload_len = hashstr[2:4] ???mask = hashstr[4:8] ???decoded = hashstr[8:]# 当位运算结果等于126时,则第3-4个字节为数据长度# 第5-8字节为mask 解密所需字符串# 则数据为第9字节至结尾if payload <= 125: ???extend_payload_len = None ???mask = hashstr[2:6] ???decoded = hashstr[6:]# 当位运算结果小于等于125时,则这个数字就是数据的长度# 第3-6字节为mask 解密所需字符串# 则数据为第7字节至结尾str_byte = bytearray()for i in range(len(decoded)): ???byte = decoded[i] ^ mask[i % 4] ???str_byte.append(byte)print(str_byte.decode("utf8"))

import structmsg_bytes = "hello".encode("utf8")token = b"\x81"length = len(msg_bytes)if length < 126: ???token += struct.pack("B", length)elif length == 126: ???token += struct.pack("!BH", 126, length)else: ???token += struct.pack("!BQ", 127, length)msg = token + msg_bytesprint(msg)