#!/usr/bin/python
# small server program
# which saves input from socket to a file
# supports only a single session from one tcp client
# can be tested with: telnet <hostname> <portnumber>
# peter.bauer@inode.at

import socket, time 
filename="/var/log/call_log.txt"

while 1:                    # repeat forvever
  fileh=open(filename,"a")  # open file for appending
  HOST = ''                 # Symbolic name meaning all available interfaces
  PORT = 20000              # Arbitrary non-privileged port
  try:                      # listen, only for a single session
    s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
    s.bind((HOST, PORT))
    s.listen(1)
    conn, addr = s.accept()
    print 'Connected by', addr

    while 1:                 # repeat while data from tcp socket
      data = conn.recv(1024) # wait for a message to arrive
      if not data: break     # 
      conn.send(data)        # send echo back to sender
      fileh.write(data)      # write to file
      fileh.flush()          # flush data to file
      print data,            # only for diagnosis
    conn.close()             # close conn
    fileh.close()            # close filehandle 
                             # repeat with file open 
                             # catch error:
  except socket.error:	     # can happen on socket open
      if s:		     # if tcp port is still used from	
           s.close()         # previous session
      print "Could not open socket: " 
      time.sleep(10)         # continue listening