Windows alternative to pexpect

Question

I'm trying to write a cross-platform tool that runs specific commands, expects certain output for verification, and sends certain output (like username/password) for authentication.

On Unix, I have been successful in programming a Python tool that uses the pexpect library (via pip install pexpect). This code works perfectly and is exactly what I am trying to do. I've provided a small excerpt of my code for proof-of-concept below:

self.process = pexpect.spawn('/usr/bin/ctf', env={'HOME':expanduser('~')}, timeout=5)
self.process.expect(self.PROMPT)
self.process.sendline('connect to %s' % server)
sw = self.process.expect(['ERROR', 'Username:', 'Connected to (.*) as (.*)'])
if sw == 0:
    pass
elif sw == 1:
    asked_for_pw = self.process.expect([pexpect.TIMEOUT, 'Password:'])
    if not asked_for_pw:
        self.process.sendline(user)
        self.process.expect('Password:')
    self.process.sendline(passwd)
    success = self.process.expect(['Password:', self.PROMPT])
    if not success:
        self.process.close()
        raise CTFError('Invalid password')
elif sw == 2:
    self.server = self.process.match.groups()[0]
    self.user = self.process.match.groups()[1].strip()
else:
    info('Could not match any strings, trying to get server and user')
    self.server = self.process.match.groups()[0]
    self.user = self.process.match.groups()[1].strip()
info('Connected to %s as %s' % (self.server, self.user))

I tried running the same source on Windows (changing /usr/bin/ctf to c:/ctf.exe) and I receive an error message:

Traceback (most recent call last):
  File ".git/hooks/commit-msg", line 49, in <module> with pyctf.CTFClient() as c:
  File "C:\git-hooktest\.git\hooks\pyctf.py", line 49, in __init__
    self.process = pexpect.spawn('c:/ctf.exe', env={'HOME':expanduser('~')}, timeout=5)
  AttributeError: 'module' object has no attribute 'spawn'

According to the pexpect documentation:

pexpect.spawn and pexpect.run() are not available on Windows, as they rely on Unix pseudoterminals (ptys). Cross platform code must not use these.

That led me on my search for a Windows equivalent. I have tried the popular winpexpect project here and even a more recent (forked) version here, but neither of these projects seem to work. I use the method:

self.process = winpexpect.winspawn('c:/ctf.exe', env={'HOME':expanduser('~')}, timeout=5)

only to sit and watch the Command Prompt do nothing (it seems as though it's trapped inside the winspawn method). I was wondering what other means I could go about programming a Python script to interact with the command line to achieve the same effect as I have been able to in Unix? If a suitable working Windows-version pexpect script does not exist, what other means could I use to go about this?

Solution

You can use wexpect ("Windows alternative of pexpect", Python Software Foundation). It has the same functions, and it works on Windows .

Comments

[Mario Román]

Please note that PopenSpawn is not a direct replacement for spawn, and this solution may not work with interactive terminal programs.

[ChrisCantrell]

I had to do an extra import to get this working. See github.com/pexpect/pexpect/issues/328

[Sylvaus]

Could you provide an example of DockerFile or docker-compose.yml showing how someone can encapsulate a Python script in docker? Also could you mention what are required for docker to be able to run Linux container in Windows to provide a better, more complete answer to the question ?

[katheravan arumugam]

The Example for Encapsulating Python in container: In Linux : Step 1: docs.docker.com/engine/install/centos After the installation ,one can get docker as a sytem command in linux. Step 2 : Create a directory , and copy the python in that directory and create a ne file called "Dockerfile" and also have the requirements.txt