pretty simple websocket server in Python (44 lines)

server.py

import socket
from hashlib import sha1
from base64 import b64encode
from sys import stdout

client = None

server = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
server.bind(('', 80))
server.listen(5)
client= server.accept()[0]
header = client.recv(3000)
key = None
for line in header.split(b'\r\n'):
	if b'Sec-WebSocket-Key' in line:
		key = line[19::]
if key is None:
	print("not a websocket")
	client.shutdown(socket.SHUT_RDWR)
	client.close()
	exit()
key += b'258EAFA5-E914-47DA-95CA-C5AB0DC85B11'
client.send(b'''\
HTTP/1.1 101 Switching Protocols\r\n\
Upgrade: WebSocket\r\n\
Connection: Upgrade\r\n\
Sec-WebSocket-Accept: %b\r\n\r\n''' % b64encode(sha1(key).digest()))

try:
	while True:
		msg = bytearray(client.recv(100))
		mask = msg[2:6:]
		payload_len = msg[1] & 0b01111111
		if payload_len >= 126:
			print('error data too long')
			exit(1)
		for i in range(payload_len):
			msg[i] = msg[6+i] ^ mask[i % 4]
			stdout.write(chr(msg[i]))
		stdout.write('\n')
		client.send(b'\x81\x06Hello!')
finally:
	client.shutdown(socket.SHUT_RDWR)
	client.close()