Interactive socket connection

[Rayed Al-Rashed]

Thanks for the response, flush() helped a little, but I faced another 
problem, waiting for input. I built another version it work great using 
"select" module to poll both the socket and stdin.

The finished program is a POP proxy that accept the connection from the 
user and depending on the user name it forward the connection to the proper 
POP3 server (configured by getuserserver function):
for example user "rayed" go to server "r.pop.mydomain.com"

Thanks a lot for your advice, any ideas on how to improve it? :)

------------------------------------
#!/usr/local/bin/python

import sys
import string
import socket
import select


def getuserserver(user):
     server = "%s.pop.mydomain.com" % (user[0], )
     return (user, server)


print "+OK POP3 server ready"
sys.stdout.flush()

# GET USER NAME
while 1:
         s = sys.stdin.readline()
         s = string.strip(s)
         s = string.lower(s)
         try:
                 (command, username) = string.split(s, " ", 2)
         except:
                 command = s
         if command == "user":
                 break
         elif command == "quit":
                 print "+OK Sayonara"
                 sys.exit()
         else:
                 print "-ERR Unknown AUTHORIZATION state command"
                 sys.stdout.flush()

(id,server) = getuserserver(username)


s = socket.socket(socket.AF_INET,socket.SOCK_STREAM)
s.connect((server, 110))
buf = s.recv(8000)
s.send("USER %s\r\n" % (id,))

while 1:
         r,w,e = select.select ([sys.stdin,s], [], [sys.stdin,s])

         if s in r:
                 buf = s.recv(8000)
                 if not buf:
                         # Connection closed
                         break
                 sys.stdout.write(buf)
                 sys.stdout.flush()

         if sys.stdin in r:
                 buf = sys.stdin.readline()
                 s.send(buf)
------------------------------------




Peter Hansen wrote:
> Rayed Al-Rashed wrote:
> 
>>Hello,
>>
>>I am trying to build POP3 proxy, I want it to run from "inetd" so it should
>>communicate with the user using regular stdin, stdout.
>>I built a small code that should run as general proxy for any protocol, but
>>I faced the following problem, it doesn't show any output from the server
>>until I pass it a command [...]
> 
> 
> Are you maybe in need of a sys.stdout.flush() to get the output to
> be sent after the sys.stdout.write()?
> 
> -Peter