#!/usr/bin/python

import sys, os, socket, time, traceback
from select import select

server_handshake = """HTTP/1.1 101 Web Socket Protocol Handshake\r
Upgrade: WebSocket\r
Connection: Upgrade\r
WebSocket-Origin: %s\r
WebSocket-Location: ws://%s%s\r
WebSocket-Protocol: sample\r
\r
"""

def handshake(client):
    handshake = client.recv(255)
    req_lines = handshake.split("\r\n")
    _, path, _ = req_lines[0].split(" ")
    _, origin = req_lines[4].split(" ")
    _, host = req_lines[3].split(" ")
    client.send(server_handshake % (origin, host, path))

def proxy(client, target):
    cqueue = []
    tqueue = []
    socks = [client, target]

    while True:
        ins, outs, excepts = select(socks, socks, socks, 1)
        if excepts: raise Exception("Socket exception")

        if client in ins:
            buf = client.recv(1024)
            if len(buf) == 0: raise Exception("Client closed")
            tqueue.append(buf[1:-1])
            print "Client recv: %s (%d)" % (buf[1:-1], len(buf))

        if target in ins:
            buf = target.recv(1024)
            if len(buf) == 0: raise Exception("Target closed")
            cqueue.append("\x00" + buf + "\xff")
            print "Target recv: %s (%d)" % (buf, len(buf))

        if cqueue and client in outs:
            while cqueue:
                print "Client send: %s" % cqueue[0]
                client.send(cqueue.pop(0))

        if tqueue and target in outs:
            while tqueue:
                print "Target send: %s" % tqueue[0]
                target.send(tqueue.pop(0))

def start_server(listen_port, target_host, target_port):
    lsock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
    lsock.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
    lsock.bind(('', listen_port))
    lsock.listen(100)
    while True:
        try:
            csock = tsock = None
            print 'listening on port %s' % listen_port
            csock, address = lsock.accept()
            print 'Got client connection from %s' % address[0]
            handshake(csock)
            print "Connecting to: %s:%s" % (target_host, target_port)
            tsock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
            tsock.connect((target_host, target_port))

            proxy(csock, tsock)

        except Exception:
            print "Ignoring exception:"
            print traceback.format_exc()
            if csock: csock.close()
            if tsock: tsock.close()

if __name__ == '__main__':
    try:
        if len(sys.argv) != 4: raise
        listen_port = int(sys.argv[1])
        target_host = sys.argv[2]
        target_port = int(sys.argv[3])
    except:
        print "Usage: <listen_port> <target_host> <target_port>"
        sys.exit(1)
    start_server(listen_port, target_host, target_port)