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!!

score 3 · Answer 1 · answered May 14 '14 at 17:32

3

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

answered May 14 '14 at 17:32

Dan Hogan

2,323
1
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16

Thanks for your reply. Unfortunately no joy. The executable immediately stops responding and the pipeline crashes. Also, I'm running this as a batch so the running of the program is inside a `for` loop - doing it like this doesn't make the rest of the script wait and it tries to launch for each sequence to be processed. (But it also fails if there is just the one sequence). The code in my question works IF I can just pause the rest of the script... – asmason May 15 '14 at 07:19

score 0 · Accepted Answer · answered May 19 '14 at 16:58

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!

Pass keyboard input to a windows executable

2 Answers2