Running an interactive subprocess with Popen

[David Liang]

Hello,
Sorry for the newbie question. How do I run a program that could
block, waiting for user input, using subprocess.Popen? For example,

from subprocess import *

def foo():
    a = Popen(['python'] ...)

I want to be able to get input from the user and send input to the
subprocess, printing stdout and stderr as data becomes available, then
return once the subprocess exits. Is it possible to send to the
subprocess keyboard interrupts, EOF, and such?

I tried doing stdout=PIPE, stderr=PIPE, stdin=PIPE. I tried using
communicate(), but could only call it once; subsequent calls raised
"ValueError: I/O operation on closed file."
And both a.stdout.read() and a.stderr.read() blocked the program. Any
help would be much appreciated.

-David