pycommand 0.3.0
A clean and simplistic alternative for argparse, optparse and getopt
Pycommand is essentially a fancy wrapper around getopt that consists of one simple CommandBase class that you can use to create executable commands for your python programs with very simplistic and readable code. It has support for subcommands and also nesting commands, so you can create (multiple levels of) subcommands, with the ability to pass the values of optional arguments of a command object to its subcommand objects. Supported Python versions are 2.7 and 3.2 and later.
- Github: https://github.com/babab/pycommand
- Bitbucket: https://bitbucket.org/babab/pycommand
- PyPI: https://pypi.python.org/pypi/pycommand/
- Documentation: http://pythonhosted.org/pycommand/
Download and install
If you have pip installed, you can just:
# pip install pycommand
To work with the current development version, do something like this:
$ git clone git://bitbucket.org/babab/pycommand.git
# cd pycommand
# pip install -e .
Quick setup from a template
To quicly start writing a command from a template (much like the examples below), use pycommand's helper script by running:
$ pycommand init
This will ask you for an executable name, class name and template type and it will save it to an executable file, ready to be used as a Python shell script (for your Python package/module)).
Example
For full documentation and examples, visit http://pythonhosted.org/pycommand/
Here is an undocumented code example of getting automated usage text
generation and parsing of optional arguments. If we name the script
for which you can see the code below basic-example
and execute it,
the following will be the output for running basic-example -h
or
basic-example --help
:
usage: basic-example [options]
An example of a basic CLI program
Options:
-h, --help show this help information
-f <filename>, --file=<filename> use specified file
--version show version information
And here is the code:
#!/usr/bin/env python
import pycommand
import sys
class BasicExampleCommand(pycommand.CommandBase):
'''An example of a basic CLI program'''
usagestr = 'usage: basic-example [options]'
description = __doc__
optionList = (
('help', ('h', False, 'show this help information')),
('file', ('f', '<filename>', 'use specified file')),
('version', ('', False, 'show version information')),
)
def run(self):
if self.flags.help:
print(self.usage)
return 0
elif self.flags.version:
print('Python version ' + sys.version.split()[0])
return 0
elif self.flags.file:
print('filename = ' + self.flags.file)
return 0
print('Program completed. Try adding "--help"')
if __name__ == '__main__':
# Shortcut for reading from sys.argv[1:] and sys.exit(status)
pycommand.run_and_exit(BasicExampleCommand)
# The shortcut is equivalent to the following:
# cmd = BasicExampleCommand(sys.argv[1:])
# if cmd.error:
# print('error: {0}'.format(cmd.error))
# sys.exit(1)
# else:
# sys.exit(cmd.run())
Why was it created?
When parsing command line program arguments, I sometimes work with argparse (a replacement for optparse). I don't really like the API and the output it gives, which is the main reason I've always used getopt for parsing arguments whenever possible.
The CommandBase class was originally written for DisPass, which is a password manager/generator, as a means to easily define new subcommands and have auto-generated usage messages. Because I want to have this in other projects I've decided to put it in the cheeseshop.
Software license
Copyright (c) 2013-2016 Benjamin Althues <benjamin@althu.es>
Permission to use, copy, modify, and distribute this software for any purpose with or without fee is hereby granted, provided that the above copyright notice and this permission notice appear in all copies.
THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.