bashpass.py

##  bashpass.py
# inspired by http://www.bash.org/?244321 and http://code.activestate.com/recipes/134892/
# This is a very nasty first effort. The next step is to shoe horn this
# functionality into getpass.py in the standard library. Demo via:
# python bashpass.py

class _Getch:
    """Gets a single character from standard input.  Does not echo to the
screen."""
    def __init__(self):
        try:
            self.impl = _GetchWindows()
        except ImportError:
            self.impl = _GetchUnix()

    def __call__(self): return self.impl()


class _GetchUnix:
    def __init__(self):
        import tty, sys

    def __call__(self):
        import sys, tty, termios
        fd = sys.stdin.fileno()
        old_settings = termios.tcgetattr(fd)
        try:
            tty.setraw(sys.stdin.fileno())
            ch = sys.stdin.read(1)
        finally:
            termios.tcsetattr(fd, termios.TCSADRAIN, old_settings)
        return ch


class _GetchWindows:
    def __init__(self):
        import msvcrt

    def __call__(self):
        import msvcrt
        return msvcrt.getch()

def getpass(bullets='hunter2'):
    import sys
    password = ''
    character = getch()
    length = len(bullets)
    output = 0
    entropy = [3,1,2,3,1,2,0,1,2]
    while character not in ('\r','\n','\x03'):
        password += character
        if output == length-entropy[0]:
            entropy.append(entropy.pop(0))
            sys.stdout.write('\b \b')
            output -= 1
        else:
            try:
                sys.stdout.write(bullets[output])
                output += 1
            except IndexError:
                sys.stdout.write('\b \b')
                output -= 1

        character = getch()
    bullets += '\n'
    sys.stdout.write(bullets[output-len(bullets):])
    return password

getch = _Getch()

if __name__ == '__main__':
    import sys
    sys.stdout.write('password: ')
    password = getpass();
    print "You entered '%s'" % password