Candela is a simple shell-building system that uses python and curses to help developers create customized command line interfaces. It has a simple interface, is well documented, and allows developers to take command-based tools to the next level of complexity and usability.
- Commands are 100% python and can run aribtrary code
- Commands can run code in secondary threads for asynchronous operation
- Responsive layout for smaller terminals
- Numerous built-in command templates
- Simple command syntax and help system
- "stickers" allow persistent information display
- Automatically generated command validation
- Up/Down arrows cycle through history
- Copy/Paste, insert text mode
- Easy transitions between menus
- Supports both named and positional command arguments
There is an example shell project in shell_example.py
. To run it, use
python shell_example.py
in a maximized terminal window.
Download the source from PyPI with
pip install candela
You can also clone this repo to take a closer look at the code and demo app.
git clone https://github.com/emmett9001/candela.git
Then, install the library with
python setup.py install
Import Candela commands, menus, and the shell
from candela.shell import Shell
from candela.menu import Menu
from candela.command import Command
from candela import constants
Alternatively, you can simply import candela
and reference the components
with candela.shell.Shell
, etc.
Every Candela app is built as a subclass of candela.shell.Shell
. A Shell
initialization follows this general outline:
- Set
self.name
- Set
self.header
- Define and instantiate
Command
s - Define and instantiate
Menu
s - Add
Command
s toMenu
s - Set
self.menus
to contain instantiatedMenu
s - Set
self.menu
to be the name of the default menu
In general, a command instantiation looks like this
com = Command('first_command', 'Intro to commands')
def _run(*args, **kwargs):
# do anything
return constants.CHOICE_VALID
com.run = _run
return com
Functions that execute on command invocation are modeled as python first-class functions (callbacks).
Please see the shell example for a full walkthrough of how to use Candela. This example is both well-commented and an instructional app demonstrating Candela's features.
The name "Candela" was chosen after Spanish architect Felix Candela, who pioneered the technique of building shell-shaped structures out of reinforced concrete. He is sometimes known as the "shell builder".
If you need help using Candela, or have found a bug, please create an issue on the Github repo.
Copyright 2013 Emmett Butler
Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at
http://www.apache.org/licenses/LICENSE-2.0
Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.