Python 诅咒 ERR 管道

Question

I would like to reproduce the result of a curses python script when a key is pressed for a pipeline.

Let's consider the following python script:

import curses

class Sf:
    def __init__(self):

        self.window = curses.initscr()
        curses.start_color()
        curses.use_default_colors()
        curses.noecho()
        curses.curs_set(False)
        self.window.keypad(True)
        self.window.addstr(0, 1, "Test")
        while True:
            key = self.window.getch()
            if key == ord("q"):
                self.window.keypad(False)
                curses.nocbreak()
                curses.echo()
                curses.endwin()
                break

sf = Sf()

To inject the key press I am using subprocess.run :

>>> from subprocess import run
>>> run(["python", "example.py"], input="q", encoding="ASCII", capture_output=True, env={"TERM": "xterm-256color"})
CompletedProcess(args=['python', 'example.py'], returncode=1, stdout='\x1b[?1049h\x1b[22;0;0t\x1b[1;24r\x1b(B\x1b[m\x1b[4l\x1b[?7h\x1b[39;49m\x1b[?25l\x1b[?1h\x1b=\x1b[39;49m\x1b(B\x1b[m\x1b[H\x1b[2J Test\x1b[?1l\x1b>', stderr='Traceback (most recent call last):\n  File "example.py", line 26, in <module>\n    sf = Sf()\n  File "example.py", line 21, in __init__\n    curses.nocbreak()\n_curses.error: nocbreak() returned ERR\n'

Any idea about the curses error?

Thanks

Answer 1

curses reads from terminals; a pipe is not a tty.

The manual page for nocbreak says

Normally, the tty driver buffers typed characters until a newline or carriage return is typed. The cbreak routine disables line buffering and erase/kill character-processing (interrupt and flow control characters are unaffected), making characters typed by the user immediately available to the program. The nocbreak routine returns the terminal to normal (cooked) mode.

The error message refers to the code returned by nocbreak , which happens because the mode-change doesn't work for pipes. So ncurses returns ERR .

Answer 2

Pexpect is what I was looking for.