Python, mpg123 and subprocess not properly using stdin.write or communicate

问题

ok, so my google-fu really kind of sucks and I was unable to find an answer, hopefully you folks can help me ^_^

ok, so what I thought would be a simple script is seemingly not communicating with its subprocess correctly, I'm running this line by line. I'm also using the mpg123 player, this is a Linux system (well, Raspberry Pi)

    from subprocess import Popen, PIPE, STDOUT
    p = Popen(["mpg123", "-C", "test.mp3"], stdout=PIPE, stdin=PIPE, stderr=STDOUT)
    #wait a few seconds to enter this, "q" without a newline is how the controls for the player work to quit out if it were ran like "mpg123 -C test.mp3" on the command line
    p.communicate(input='q')[0]

I can run stdout.read() on it just fine, but using communicate for input just makes it hang and p.stdin.write('q') does seemingly nothing at all. This is python related though I have a feeling I'm also not looking in the right place in the mpg123 documentation. Please be kind as I'm exceptionally new to this ^_^

回答1:

Check what arguments your mpg123 version understands. The following works on my machine:

#!/usr/bin/env python3
import time
from subprocess import Popen, PIPE, DEVNULL, STDOUT

p = Popen(["mpg123", "-K", "test.mp3"], stdin=PIPE, stdout=DEVNULL, stderr=STDOUT)

# wait a little
time.sleep(3)

# send command "Skip song", wait for the player to exit
p.communicate(b'n')[0]

It starts playing the file, waits ~3 seconds, and exits.

来源：https://stackoverflow.com/questions/17159627/python-mpg123-and-subprocess-not-properly-using-stdin-write-or-communicate