websocket的加密和解密

补充个小知识点：按位与运算

按位与运算是同位都为1才为1，有一个不为1就是0

websocket_hand

import socket, base64, hashlib
import websocket_jiemi
import websocket_jiami

sock = 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() # 阻塞

# 获取客户端的【握手】信息
data = conn.recv(2048)
print(data)


"""
b'
GET / HTTP/1.1

Host: 127.0.0.1:9527

Connection: Upgrade

Pragma: no-cache

Cache-Control: no-cache

User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/69.0.3497.100 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

Sec-WebSocket-Key: tPWfDfGthkhhqfY4ZdT1yQ==

Sec-WebSocket-Extensions: permessage-deflate; client_max_window_bits

'
"""
#
# # magic string为：258EAFA5-E914-47DA-95CA-C5AB0DC85B11
magic_string = '258EAFA5-E914-47DA-95CA-C5AB0DC85B11'
#
#
def get_headers(data):
    header_dict = {}
    header_str = data.decode("utf8")
    for i in header_str.split("
"):
        if str(i).startswith("Sec-WebSocket-Key"):
            header_dict["Sec-WebSocket-Key"] = i.split(":")[1].strip()

    return header_dict

headers = get_headers(data)  # 提取请求头信息

# # 对请求头中的sec-websocket-key进行加密

#
value = headers['Sec-WebSocket-Key'] + magic_string  # jtl/vockZ8GRyadFVeiUTA==258EAFA5-E914-47DA-95CA-C5AB0DC85B11
print(value)
sha1_value = hashlib.sha1(value.encode('utf-8')).digest()
print("sha1_value",sha1_value)
ac = base64.b64encode(sha1_value)
print("ac",ac)
# ac  - sha1(sec+magic) - base64
response_tpl = "HTTP/1.1 101 Switching Protocols
" 
               "Upgrade:websocket
" 
               "Connection: Upgrade
" 
               "Sec-WebSocket-Accept: %s
" 
               "WebSocket-Location: ws://127.0.0.1:9527

"

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)
    msg = websocket_jiemi.websocket_jiema(msg)

    # conn.send("123123123123".encode("utf8"))
    send_str = websocket_jiami.jiami("hello".encode("utf8"))
    print(send_str)
    conn.send(send_str)

websocket_jiami

import struct
# msg_bytes = "哎呀妈呀脑瓜疼".encode("utf8")
def jiami(msg_bytes):
    token = b"x81"
    length = len(msg_bytes)

    if length < 126:
        token += struct.pack("B", length) # x85$
    elif length == 126:
        token += struct.pack("!BH", 126, length)
    else:
        token += struct.pack("!BQ", 127, length)

    msg = token + msg_bytes

    return msg

websocket_jiemi

# b'x81x83xceHxb6x85xffzx85'

hashstr = b'x81x85$xcb>x14LxaeRxK'
# b'x81
# x85$
# xcb>x14LxaeRxKxcb>x14LxaeRxKxcb>x14L
# xaeRxKxcb>x14LxaeRxK
# xcb>x14LxaeRxKxcb>x14LxaeRxKxcb>x14LxaeRxKxcb>x14LxaeRxKxcb>x14LxaeRxKxcb>x14LxaeRxKxcb>x14LxaeRxKxcb>x14LxaeRxK'

# 将第二个字节也就是 x83 第9-16位 进行与127进行位运算

def websocket_jiema(hashstr):
    print(hashstr[1])
    payload = hashstr[1] & 127
    print(payload)

    if payload == 127:
        extend_payload_len = hashstr[2:10] # 834473503
        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
    #

    # b'x81
    # x85$    126
    # xcb>x14L 120
    # xaeRxKxcb>x14LxaeRxK
    # xcb>x14LxaeRxKxcb>x14LxaeRxK xcb>x14LxaeRxKxcb>x14LxaeRxKxcb>x14LxaeRxKxcb>x14LxaeRxKxcb>x14LxaeRxKxcb>x14LxaeRxKxcb>x14LxaeRxKxcb>x14LxaeRxK'


    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
    #
    #   b'x81
    # x85$ 5 len数据长度
    # xcb>x14LxaeRxK'

    if payload <= 125:
        extend_payload_len = payload
        mask = hashstr[2:6]
        decoded = hashstr[6:]  # 5

    # 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)
    #
    return str_byte.decode("utf8")

my_socket

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

</body>
<script>
    var ws = new WebSocket("ws://127.0.0.1:9527")
    ws.onmessage = function (data) {
        console.log(data.data)

    }
</script>
</html>