pexpect.ANSI demo

gistfile1.py

#!/usr/bin/env python2
"""
Copyright (c) 2015, Jason Heeris

Permission to use, copy, modify, and/or distribute this software for any purpose with or without fee is hereby granted, provided that the above copyright notice and this permission notice appear in all copies.

THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
"""

import fcntl
import os
import pty
import subprocess
import struct
import termios
import time

import pexpect.ANSI

# Don't rely on inheriting dimensions from the user's terminal.
SUBJECT_ROWS = 24
SUBJECT_COLS = 80

# Psuedo-terminal FDs
fd_master, fd_slave = pty.openpty()

# From ptyprocess source.
TIOCSWINSZ = getattr(termios, 'TIOCSWINSZ', -2146929561)
ioctl_struct = struct.pack('HHHH', SUBJECT_ROWS, SUBJECT_COLS, 0, 0)
fcntl.ioctl(fd_slave, TIOCSWINSZ, ioctl_struct)

# Start 'top'
top_proc = subprocess.Popen(
    ['top'],
    stdin=fd_slave, stdout=fd_slave, stderr=subprocess.STDOUT,
    close_fds=True)

# Just kill it after a couple of seconds, by sending the 'q' keystroke.
time.sleep(2)
os.write(fd_master, 'q')

top_proc.wait()

print("Process ended.")

# Read output into a buffer
output_buffer = b''
read_size = None

os.close(fd_slave)

try:
    while (read_size is None) or (read_size > 0):
        chunk = os.read(fd_master, 1024)
        output_buffer += chunk
        read_size = len(chunk)
        print("Read: {:d}".format(read_size))
except OSError as io_error:
    pass

print("Output buffer size: {:d}".format(len(output_buffer)))

# Render the result with pexpect's ANSI terminal emulator.
ansi_term = pexpect.ANSI.ANSI(SUBJECT_ROWS, SUBJECT_COLS)
ansi_term.write(output_buffer)
print(ansi_term)