#! /usr/bin/python
import getopt, socket, SocketServer, threading, sys
__version__ = "0.2"

def show_version():
  print 'mm v'+__version__+', by Rimon Barr:',
  print 'Network middle-man.'

def show_usage():
  show_version()
  print
  print 'Usage: mm [--listen=<port>] <host>:<port>'
  print '       mm -h | -v'
  print 
  print '  -h, -?, --help           display this help information'
  print '  -v, --version            display version'
  print '  --listen=<port>          set listen port'
  print
  print 'Send comments, suggestions and bug reports to <rimon@acm.org>.'

def usage_error():
  print 'mm: command syntax error'
  print 'Try `mm --help\' for more information.'

def parse_hostport(s):
  try: host, port = s.split(':')
  except TypeError: 'expect string of format -- host:port'
  return host, int(port)

def logpipe(fin, fout, flog, label=''):
  if not label: label = fin
  try:
    c = fin.read(1)
    while c:
      fout.write(c); fout.flush()
      flog.write(c, label)
      c = fin.read(1)
  except IOError: pass
  fout.close()

class multilog(object):
  def __init__(self, fout): 
    self.__fout, self.__src, self.__buf = fout, None, ''
  def write(self, c, src):
    if src!=self.__src: self.flush(); self.__src=src
    self.__buf += c
  def flush(self):
    if self.__buf: 
      buf,self.__buf = ''.join(['\\x%02x'%ord(c) for c in self.__buf]),''
      print >> self.__fout, "%s: '%s'" % (self.__src, buf)
      self.__fout.flush()
  def __del__(self): self.flush()

def mm():
  try: opts, args = getopt.getopt(sys.argv[1:], 'hv?',
      ['help', 'version', 'listen='])
  except getopt.GetoptError, e: print e; usage_error(); return
  listenport = None
  # process options
  for o, a in opts:
    if o in ("-h", "--help", "-?"): show_usage(); return
    if o in ("-v", "--version"): show_version(); return
    if o in ('--listen'): listenport = int(a)
  if len(args)!=1: usage_error(); return
  host, port = parse_hostport(args[0])
  if listenport is None: listenport = port
  lout = multilog(sys.stdout)

  # define server
  class mysrv(SocketServer.ThreadingTCPServer):
    allow_reuse_address = True
    daemon_threads = True

  # define connection handler
  class myconn(SocketServer.StreamRequestHandler):
    def handle(self):
      s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
      s.connect((host,port))
      cin, cout = self.rfile, self.wfile
      sin, sout = s.makefile('r',1024), s.makefile('w',1024)
      tin  = threading.Thread(target=logpipe, args=(cin,sout,lout,'C'))
      tout = threading.Thread(target=logpipe, args=(sin,cout,lout,'S'))
      tin.setDaemon(1); tin.start()
      tout.setDaemon(1); tout.start()
      tin.join(); tout.join()

  srv = mysrv(('',listenport), myconn)
  print 'Logging: localhost:%d <--> %s:%d' % (listenport,host,port)
  try:
    srv.socket.settimeout(1)
    while True:
      try: srv.handle_request()
      except KeyboardInterrupt: raise
      except: print >> sys.stderr, 'Error: %s' % fn.exceptionStr()
  except KeyboardInterrupt: pass
  lout.flush()
  srv, lout = None, None
  sys.exit(0)

if __name__=='__main__': mm()