Pass keyboard input to a windows executable

Question

I am creating a Python batch script for a piece of software that must run as a windows executable in C:\ The pipeline is almost set up. But the executable requires some keyboard entry before it starts. Before trying to pass keyboard entry it worked with subprocess.call() but I couldn't get the syntax to work for communicate(). This is commented out below.

I have tried now with win32com add on SendKeys (see below), but now the main script carries on before the executable finishes. Any advice on my code? Can I log the exit status of the executable to use a while loop just to sleep the main process until the executable finishes?

#subprocess.call(r"C:\LTR_STRUC\LTR_STRUC_1_1.exe")
shell = win32com.client.Dispatch("WScript.shell")
Return = shell.Run(r"C:\LTR_STRUC\LTR_STRUC_1_1.exe")
time.sleep(2)
shell.AppActivate(r"C:\LTR_STRUC\LTR_STRUC_1_1.exe")
shell.SendKeys("y", 0)
shell.SendKeys("{Enter}", 0)
time.sleep(1)
shell.SendKeys("y", 0)
shell.SendKeys("{Enter}", 0)
time.sleep(1)
shell.SendKeys("{Enter}", 0)

###...and on goes the code...

Any other clever suggestions will be much appreciated!!

Answer 1

Managed to solve it using another function of the Pywin module - win32ui It works as above in the question but then has this:

import win32ui

def WindowExists(windowname):
    try:
        win32ui.FindWindow(None, windowname)

    except win32ui.error:
        return False
    else:
        return True

process = True
while process == True:
    if WindowExists(r"C:\LTR_STRUC\LTR_STRUC_1_1.exe"):
        process = True
    else:
        process = False
        time.sleep(5)

Essentially, this tests for the presence of the executable window/process. Whilst the window exists you know the program is still going, so the rest of the script doesn't continue.

Hope this is useful to someone else at some point!

Answer 2

Give this a try:

import os
from subprocess import Popen, PIPE
cmd = r"C:\LTR_STRUC\LTR_STRUC_1_1.exe"

app = Popen(cmd, stdin=PIPE, shell=True)
app.stdin.write("y" + os.linesep)
...

Also if you wanted respond to a prompt you could PIPE stdout as well and access it via:

app.stdout.read()

reference: https://docs.python.org/2/library/subprocess.html#subprocess.PIPE