blessed 1.15.0

A thin, practical wrapper around terminal styling, screen positioning, and keyboard input.

Introduction

Blessed is a thin, practical wrapper around terminal capabilities in Python.

Coding with Blessed looks like this…

from blessed import Terminal

t = Terminal()

print(t.bold('Hi there!'))
print(t.bold_red_on_bright_green('It hurts my eyes!'))

with t.location(0, t.height - 1):
    print(t.center(t.blink('press any key to continue.')))

with t.cbreak():
    inp = t.inkey()
print('You pressed ' + repr(inp))

Brief Overview

Blessed is a more simplified wrapper around curses, providing :

• Styles, color, and maybe a little positioning without necessarily clearing the whole screen first.

• Works great with standard Python string formatting.

• Provides up-to-the-moment terminal height and width, so you can respond to terminal size changes.

• Avoids making a mess if the output gets piped to a non-terminal: outputs to any file-like object such as StringIO, files, or pipes.

• Uses the terminfo(5) database so it works with any terminal type and supports any terminal capability: No more C-like calls to tigetstr and tparm.

• Keeps a minimum of internal state, so you can feel free to mix and match with calls to curses or whatever other terminal libraries you like.

• Provides plenty of context managers to safely express terminal modes, automatically restoring the terminal to a safe state on exit.

• Act intelligently when somebody redirects your output to a file, omitting all of the terminal sequences such as styling, colors, or positioning.

• Dead-simple keyboard handling: safely decoding unicode input in your system’s preferred locale and supports application/arrow keys.

• Allows the printable length of strings containing sequences to be determined.

Blessed does not provide…

• Windows command prompt support. A PDCurses build of python for windows provides only partial support at this time – there are plans to merge with the ansi module in concert with colorama to resolve this. Patches welcome!

Before And After

With the built-in curses module, this is how you would typically print some underlined text at the bottom of the screen:

from curses import tigetstr, setupterm, tparm
from fcntl import ioctl
from os import isatty
import struct
import sys
from termios import TIOCGWINSZ

# If we want to tolerate having our output piped to other commands or
# files without crashing, we need to do all this branching:
if hasattr(sys.stdout, 'fileno') and isatty(sys.stdout.fileno()):
    setupterm()
    sc = tigetstr('sc')
    cup = tigetstr('cup')
    rc = tigetstr('rc')
    underline = tigetstr('smul')
    normal = tigetstr('sgr0')
else:
    sc = cup = rc = underline = normal = ''

# Save cursor position.
print(sc)

if cup:
    # tigetnum('lines') doesn't always update promptly, hence this:
    height = struct.unpack('hhhh', ioctl(0, TIOCGWINSZ, '\000' * 8))[0]

    # Move cursor to bottom.
    print(tparm(cup, height - 1, 0))

print('This is {under}underlined{normal}!'
      .format(under=underline, normal=normal))

# Restore cursor position.
print(rc)

The same program with Blessed is simply:

from blessed import Terminal

term = Terminal()
with term.location(0, term.height - 1):
    print('This is' + term.underline('underlined') + '!')

Requirements

Blessed is tested with Python 2.7, 3.4, and 3.5 on Debian Linux, Mac, and FreeBSD.

Further Documentation

More documentation can be found at http://blessed.readthedocs.org/en/latest/

Bugs, Contributing, Support

Bugs or suggestions? Visit the issue tracker and file an issue. We welcome your bug reports and feature suggestions!

Would you like to contribute? That’s awesome! We’ve written a guide to help you.

Are you stuck and need support? Give stackoverflow a try. If you’re still having trouble, we’d like to hear about it! Open an issue in the issue tracker with a well-formed question.

License

Blessed is under the MIT License. See the LICENSE file.

Forked

Blessed is a fork of blessings. Changes since 1.7 have all been proposed but unaccepted upstream.

Furthermore, a project in the node.js language of the same name is not related, or a fork of each other in any way.