Print to standard console in curses

Question

I'm building a python curses application.

I have two ways of printing to the curses window: print x, and windows.addstr(x) (and the other similar window.* options).

However, for debugging purposes, I'd like to be able to print to the standard console, so when I exit the curses window, I have the infomation waiting for me to be seen. I would normally just use print x, but that prints to the curses window.

sys.stout.write() also fails.

How can I do this?

After using sys.stdout after os.fdopen, this is the traceback

 curses.nocbreak()
 _curses.error: nocbreak() returned ERR
 close failed in file object destructor:
 sys.excepthook is missing
 lost sys.stderr

Solution 1

To do as you say, here is a snippet I used:

class StdOutWrapper:
    text = ""
    def write(self,txt):
        self.text += txt
        self.text = '\n'.join(self.text.split('\n')[-30:])
    def get_text(self,beg,end):
        return '\n'.join(self.text.split('\n')[beg:end])

if __name__ == "__main__":
    mystdout = StdOutWrapper()
    sys.stdout = mystdout
    sys.stderr = mystdout

    screen = curses.initscr()
    curses.noecho()
    curses.cbreak()

    # do your stuff here
    # you can also output mystdout.get_text() in a ncurses widget in runtime

    screen.keypad(0)
    curses.nocbreak()
    curses.echo()
    curses.endwin()
    sys.stdout = sys.__stdout__
    sys.stderr = sys.__stderr__
    sys.stdout.write(mystdout.get_text())

The neat thing with that trick, is that you can also output your stdout during ncurse runtime in a widget. Of course the internal representation of StdOutWrapper can be tweaked as you want, to better match your needs.

Solution 2

Why don't you use the standard logging module?

Combine it with curses.wrapper, and you are good to go

---

EDIT:

You can see example here: https://stackoverflow.com/a/28102809/26494

If you just want to log to file:

import logging
import curses

def draw(stdscr):
    logger = logging.getLogger(__file__)
    hdlr = logging.FileHandler(__file__ + ".log")
    formatter = logging.Formatter('%(asctime)s %(levelname)s %(message)s')
    hdlr.setFormatter(formatter)
    logger.addHandler(hdlr)
    logger.setLevel(logging.DEBUG)

    logger.info("begin")

    curses.init_pair(1, curses.COLOR_CYAN, curses.COLOR_BLACK)
    stdscr.addstr(0, 0, 'hello', curses.color_pair(1))
    logger.info("yeah")
    stdscr.getch()
    logger.info("end")


if __name__ == '__main__':
    curses.wrapper(draw)

Comments

[ACarter]

That's an interesting solution I had never thought of before. Thanks.