prompters.py 文件源码

def stdout_redirected(to):
    """Lifted from: https://stackoverflow.com/questions/4675728/redirect-stdout-to-a-file-in-python

    This is the only way I've found to redirect stdout with curses. This way the
    output from questionnaire can be piped to another program, without piping
    what's written to the terminal by the prompters.
    """
    stdout = sys.stdout

    stdout_fd = fileno(stdout)
    # copy stdout_fd before it is overwritten
    with os.fdopen(os.dup(stdout_fd), 'wb') as copied:
        stdout.flush()  # flush library buffers that dup2 knows nothing about
        try:
            os.dup2(fileno(to), stdout_fd)  # $ exec >&to
        except ValueError:  # filename
            with open(to, 'wb') as to_file:
                os.dup2(to_file.fileno(), stdout_fd)  # $ exec > to
        try:
            yield stdout  # allow code to be run with the redirected stdout
        finally:
            # restore stdout to its previous value
            stdout.flush()
            os.dup2(copied.fileno(), stdout_fd)