#!/usr/bin/env python
import asyncore
import socket
import struct
import time
import hashlib
class WebSocketConnection(asyncore.dispatcher_with_send):
def __init__(self, conn, server):
asyncore.dispatcher_with_send.__init__(self, conn)
self.server = server
self.server.sessions.append(self)
self.readystate = "connecting"
self.buffer = ""
def handle_read(self):
data = self.recv(1024)
self.buffer += data
if self.readystate == "connecting":
self.parse_connecting()
elif self.readystate == "open":
self.parse_frametype()
def handle_close(self):
self.server.sessions.remove(self)
self.close()
def parse_connecting(self):
header_end = self.buffer.find("\r\n\r\n")
if header_end == -1:
return
else:
header = self.buffer[:header_end]
# remove header and four bytes of line endings from buffer
self.buffer = self.buffer[header_end+4:]
header_lines = header.split("\r\n")
headers = {}
# validate HTTP request and construct location
method, path, protocol = header_lines[0].split(" ")
if method != "GET" or protocol != "HTTP/1.1" or path[0] != "/":
self.terminate()
return
# parse headers
for line in header_lines[1:]:
key, value = line.split(": ")
headers[key] = value
headers["Location"] = "ws://" + headers["Host"] + path
self.readystate = "open"
self.handler = self.server.handlers.get(path, None)(self)
if "Sec-WebSocket-Key1" in headers.keys():
self.send_server_handshake_76(headers)
else:
self.send_server_handshake_75(headers)
def terminate(self):
self.ready_state = "closed"
self.close()
def send_server_handshake_76(self, headers):
"""
Send the WebSocket Protocol v.76 handshake response
"""
key1 = headers["Sec-WebSocket-Key1"]
key2 = headers["Sec-WebSocket-Key2"]
# read additional 8 bytes from buffer
key3, self.buffer = self.buffer[:8], self.buffer[8:]
response_token = self.calculate_key(key1, key2, key3)
# write out response headers
self.send_bytes("HTTP/1.1 101 Web Socket Protocol Handshake\r\n")
self.send_bytes("Upgrade: WebSocket\r\n")
self.send_bytes("Connection: Upgrade\r\n")
self.send_bytes("Sec-WebSocket-Origin: %s\r\n" % headers["Origin"])
self.send_bytes("Sec-WebSocket-Location: %s\r\n" % headers["Location"])
if "Sec-WebSocket-Protocol" in headers:
protocol = headers["Sec-WebSocket-Protocol"]
self.send_bytes("Sec-WebSocket-Protocol: %s\r\n" % protocol)
self.send_bytes("\r\n")
# write out hashed response token
self.send_bytes(response_token)
def calculate_key(self, key1, key2, key3):
# parse keys 1 and 2 by extracting numerical characters
num1 = int("".join([digit for digit in list(key1) if digit.isdigit()]))
spaces1 = len([char for char in list(key1) if char == " "])
num2 = int("".join([digit for digit in list(key2) if digit.isdigit()]))
spaces2 = len([char for char in list(key2) if char == " "])
combined = struct.pack(">II", num1/spaces1, num2/spaces2) + key3
# md5 sum the combined bytes
return hashlib.md5(combined).digest()
def send_server_handshake_75(self, headers):
"""
Send the WebSocket Protocol v.75 handshake response
"""
self.send_bytes("HTTP/1.1 101 Web Socket Protocol Handshake\r\n")
self.send_bytes("Upgrade: WebSocket\r\n")
self.send_bytes("Connection: Upgrade\r\n")
self.send_bytes("WebSocket-Origin: %s\r\n" % headers["Origin"])
self.send_bytes("WebSocket-Location: %s\r\n" % headers["Location"])
if "Protocol" in headers:
self.send_bytes("WebSocket-Protocol: %s\r\n" % headers["Protocol"])
self.send_bytes("\r\n")
def parse_frametype(self):
while len(self.buffer):
type_byte = self.buffer[0]
if type_byte == "\x00":
if not self.parse_textframe():
return
def parse_textframe(self):
terminator_index = self.buffer.find("\xFF")
if terminator_index != -1:
frame = self.buffer[1:terminator_index]
self.buffer = self.buffer[terminator_index+1:]
s = frame.decode("UTF8")
self.handler.dispatch(s)
return True
else:
# incomplete frame
return false
def send(self, s):
if self.readystate == "open":
self.send_bytes("\x00")
self.send_bytes(s.encode("UTF8"))
self.send_bytes("\xFF")
def send_bytes(self, bytes):
asyncore.dispatcher_with_send.send(self, bytes)
class EchoHandler(object):
"""
The EchoHandler repeats each incoming string to the same Web Socket.
"""
def __init__(self, conn):
self.conn = conn
def dispatch(self, data):
self.conn.send("echo: " + data)
class WebSocketServer(asyncore.dispatcher):
def __init__(self, port=80, handlers=None):
asyncore.dispatcher.__init__(self)
self.handlers = handlers
self.sessions = []
self.port = port
self.create_socket(socket.AF_INET, socket.SOCK_STREAM)
self.set_reuse_addr()
self.bind(("", port))
self.listen(5)
def handle_accept(self):
conn, addr = self.accept()
session = WebSocketConnection(conn, self)
if __name__ == "__main__":
print "Starting WebSocket Server"
WebSocketServer(port=8080, handlers={"/echo": EchoHandler})
asyncore.loop()