Use subprocess to send a password

Question

I'm attempting to use the python subprocess module to log in to a secure ftp site and then grab a file. However I keep getting hung up on just trying to send the password when it is requested. I so far have the following code:

from subprocess import Popen, PIPE

proc = Popen(['sftp','user@server', 'stop'], stdin=PIPE)
proc.communicate('password')

This still stops at the password prompt. If I enter the password manually it then goes to the ftp site and then enters the password on the command line. I've seen people suggest using pexpect but long story short I need a standard library solution. Is there anyway with subprocess and/or any other stdlib? What am I forgetting above?

Answer 1

Try

proc.stdin.write('yourPassword\n')
proc.stdin.flush()

That should work.

What you describe sounds like stdin=None where the child process inherits the stdin of the parent (your Python program).

Answer 2

Perhaps you should use an expect-like library instead?

For instance Pexpect (example). There are other, similar python libraries as well.

Answer 3

I would recommend scrapping the subprocess approach and using the paramiko package for sftp access.

Answer 4

I am stuck on a similar problem. I found Pexpect, but unfortunately it is not available for Windows. Did I miss any good expect-like library for Windows in my search?