pycommand 0.4.0

Description:

pycommand 0.4.0

Library / toolkit for creating command line programs with minimal effort.
Pycommand is essentially a fancy wrapper around getopt that consists of
one simple CommandBase class that you can inherit 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.

Documentation: https://babab.github.io/pycommand/
PyPI: https://pypi.python.org/pypi/pycommand/
Github: https://github.com/babab/pycommand


Features

Parsing of optional and positional arguments
Minimalistic approach with a clean API
Create scripts in a matter of minutes using the code generator
Auto compiled usage messages
Graceful semi-automatic handling of exit status codes
Subcommands can have subcommands that can have subcommands
(each with their own optional arguments)
Pass values for –some-option from a parent command into child commands.



Download and install
If you have pip installed, you can just do:
# pip install pycommand


Script generator
To quickly start writing a command from a template (much like the
examples below), use the script generator by running:
$ python -m pycommand init
This will ask you for an executable name, class name and template type
and it will save it to an executable python script, ready to be used as
a command line program.
You can have a very basic command line program that handles -v, --version and -h, --help arguments set up in less than a minute.


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 in 2013.
It has since been refined for more generic usage and has proven to be
stable and workable throughout the years.


Software license
Copyright (c) 2013-2016, 2018 Benjamin Althues <[email protected]>
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.


Change Log
pycommand adheres to Semantic Versioning.

0.4.0 - 2018-03-27

Added

Full templates can now (also) be auto generated
CI testing for Python 3.5 and 3.6



Changed

Note
The pycommand init script is removed and is included in the
pycommand package itself.
To auto generate scripts from templates, from now on use:

python -m pycommand init



The code is split up into several modules and pycommand is now
distributed as a package rather than a single module. The public
API does not change however, all relevant members (CommandBase,
run_and_exit) that are now placed in pycommand.pycommand are
exposed through __init__ and therefore are still available as
pycommand.CommandBase and pycommand.run_and_exit.
Code generator is included in the package itself instead of
using an installed script (pycommand init)
All templates are now embedded as well



Removed

Pycommand init script (installed into /usr/local/bin)
Templates directory
GNU info docs and manpage from distribution (they can still be generated)

pycommand.3 (prev. installed into /share/man/man3)
pycommand.info






0.3.0 - 2015-06-04

Added

Shortcut run_and_exit() for reading from sys.argv[1:] and exiting
the interpreter via sys.exit(status)
Package as wheel distribution to speed up installations
Add man pycommand ability, i.e. install mandoc in /usr/share/man3/



Changed

Add support for getting flags by attribute like self.flags.help.
The default approach for normal dicts like self.flags['help']
remains valid.




0.2.0 - 2015-05-21

Added

Full example of a command with subcommands
Create quick templates via pycommand script (pycommand init)
Unit tests and automatic testing via Travis-CI
Documentation man (.3) and info (.info) pages



Changed

Specification of subcommands can be defined in CommandBase.command
as a shortcut.




0.1.0 - 2013-08-08
Added

Initial release