websocket server

websocketserver.py

import struct
import socket
import hashlib
import sys
from select import select
import re
import logging

class WebSocket(object):
    handshake = (
        "HTTP/1.1 101 Web Socket Protocol Handshake\r\n"
        "Upgrade: WebSocket\r\n"
        "Connection: Upgrade\r\n"
        "WebSocket-Origin: %(origin)s\r\n"
        "WebSocket-Location: ws://%(bind)s:%(port)s/\r\n"
        "Sec-Websocket-Origin: %(origin)s\r\n"
        "Sec-Websocket-Location: ws://%(bind)s:%(port)s/\r\n"
        "\r\n"
    )
    def __init__(self, client, server):
        self.client = client
        self.server = server
        self.handshaken = False
        self.header = ""
        self.data = ""
        
    def feed(self, data):
        if not self.handshaken:
            self.header += data
            if self.header.find('\r\n\r\n') != -1:
                parts = self.header.split('\r\n\r\n', 1)
                self.header = parts[0]
                if self.dohandshake(self.header, parts[1]):
                    logging.info("Handshake successful")
                    self.handshaken = True           
        else:
            self.data += data
            validated = []
            msgs = self.data.split('\xff')
            self.data = msgs.pop()
            for msg in msgs:
                if msg[0] == '\x00':
                    self.onmessage(msg[1:]) 
                    
    def dohandshake(self, header, key=None): 
        logging.debug("Begin handshake: %s" % header) 
        digitRe = re.compile(r'[^0-9]')
        spacesRe = re.compile(r'\s')
        part_1 = part_2 = origin = None
        for line in header.split('\r\n')[1:]:
            name, value = line.split(': ', 1)
            if name.lower() == "sec-websocket-key1":
                key_number_1 = int(digitRe.sub('', value))
                spaces_1 = len(spacesRe.findall(value))
                if spaces_1 == 0:
                    return False
                if key_number_1 % spaces_1 != 0:
                    return False
                part_1 = key_number_1 / spaces_1
            elif name.lower() == "sec-websocket-key2":
                key_number_2 = int(digitRe.sub('', value))
                spaces_2 = len(spacesRe.findall(value))
                if spaces_2 == 0:
                    return False
                if key_number_2 % spaces_2 != 0:
                    return False
                part_2 = key_number_2 / spaces_2
            elif name.lower() == "origin":
                origin = value
        if part_1 and part_2:
            logging.debug("Using challenge + response")
            challenge = struct.pack('!I', part_1) + struct.pack('!I', part_2) + key
            response = hashlib.md5(challenge).digest()
            handshake = WebSocket.handshake + response
        else:
            logging.warning("Not using challenge + response")
            handshake = WebSocket.handshake
        handshake = handshake % {'origin': origin, 'port': self.server.port, 
                                    'bind': self.server.bind}
        logging.debug("Sending handshake %s" % handshake)   
        self.client.send(handshake)
        return True
                     
    def onmessage(self, data):
        logging.info("Got message: %s" % data)

    def send(self, data):
        logging.info("Sent message: %s" % data)
        self.client.send("\x00%s\xff" % data)
        
    def close(self):
        self.client.close()      

class WebSocketServer(object):
    def __init__(self, bind, port, cls):
        self.socket = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
        self.socket.bind((bind, port))
        self.bind = bind
        self.port = port
        self.cls = cls
        self.connections = {}
        self.listeners = [self.socket]
            
    def listen(self, backlog=5):
        self.socket.listen(backlog)
        logging.info("Listening on %s" % self.port)
        self.running = True
        while self.running:
            rList, wList, xList = select(self.listeners, [], self.listeners, 1)
            for ready in rList:
                if ready == self.socket:
                    logging.debug("New client connection")
                    client, address = self.socket.accept()
                    fileno = client.fileno()
                    self.listeners.append(fileno)
                    self.connections[fileno] = self.cls(client, self)
                else:
                    logging.debug("Client ready for reading %s" % ready)
                    client = self.connections[ready].client
                    data = client.recv(1024)
                    fileno = client.fileno()
                    if data:
                        self.connections[fileno].feed(data)
                    else:
                        logging.debug("Closing client %s" % ready)
                        self.connections[fileno].close()
                        del self.connections[fileno]
                        self.listeners.remove(ready)
            for failed in xList:
                if failed == self.socket:
                    logging.error("Socket broke")
                    for fileno, conn in self.connections:
                        conn.close()
                    self.running = False

if __name__ == "__main__":
    logging.basicConfig(level=logging.DEBUG, format="%(asctime)s - %(levelname)s - %(message)s")
    server = WebSocketServer("localhost", 9999, MyServer) 
    server_thread = Thread(target=server.listen, args=[5])
    server_thread.start()
    # Add SIGINT handler for killing the threads
    def signal_handler(signal, frame):
        logging.info("Caught Ctrl+C, shutting down...")
        server.running = False
        sys.exit()
    signal.signal(signal.SIGINT, signal_handler)