PyCon 23: Smettiamola di scrivere script
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This document provides an overview of command line interface (CLI) applications and compares different libraries for building CLIs in Python: Argparse, Click, and Docopt. It discusses some limitations of scripts and advantages of CLI applications, then gives code examples and explanations of each library.
![print("This is important code")
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for index, arg in enumerate(sys.argv):
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print(f"[{index}]: {arg}")
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What's Wrong with Scripts?
Easy to get started
Limited possibilities for structure
Hard to (unit) test
No dependency management
Deployment may require care
Custom user experience](https://image.slidesharecdn.com/pycon-23-smettiamola-di-scrivere-script-230529074945-856fc7d6/85/PyCon-23-Smettiamola-di-scrivere-script-12-320.jpg)
!["""Foobar
Usage:
foobar (-h | --help | --version)
foobar [-s | --silent] <file>
foobar [-v | --verbose] <file>
Positional arguments:
file target file path name
Optional arguments:
-h, --help show this help message and exit
-s, --silent don't show progress output
-v, --verbose explain progress verbosely
--version show program's version number and exit
"""
from docopt import docopt
from . import __version__
def parse_arguments():
args = docopt(__doc__, version=__version__)
return dict(
file=args['<file>'],
silent=args['-s'] or args['--silent'],
verbose=args['-v'] or args['--verbose'],
)
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Docopt](https://image.slidesharecdn.com/pycon-23-smettiamola-di-scrivere-script-230529074945-856fc7d6/85/PyCon-23-Smettiamola-di-scrivere-script-16-320.jpg)
PyCon 23: Smettiamola di scrivere script
- 3. Dizionario Italiano a cura di Enrico Olivetti
- 11. CLI Applications What's wrong with scripts? Why CLI Applications? 1. Argparse 2. Click 3. Docopt
- 12. print("This is important code") 1 2 for index, arg in enumerate(sys.argv): 3 print(f"[{index}]: {arg}") 4 What's Wrong with Scripts? Easy to get started Limited possibilities for structure Hard to (unit) test No dependency management Deployment may require care Custom user experience
- 13. print("Usage: foo <bar> --baz") def main(): 1 2 3 if __name__ == "__main__": 4 main() 5 Why CLI Applications? Standardized user experience More possibilities for structure Possibilities for all kinds of testing Dependency management Packaging & distribution
- 14. import argparse from . import __version__ def parse_arguments(): parser = argparse.ArgumentParser(description=__doc__) parser.add_argument('--version', action='version', version=__version__) parser.add_argument('filename') args = parser.parse_args() return args def main(): args = parse_arguments() ... 1 2 3 4 5 6 7 8 9 10 11 12 13 14 Argparse
- 15. import click @click.command() @click.version_option() @click.argument('filename') def main(filename): click.echo(filename) 1 2 3 4 5 6 7 Click import click @click.command() @click.version_option() @click.argument('filename', type=click.Path(exists=True)) def main(filename): click.echo(filename) 1 2 3 4 5 6 7 import click @click.command() @click.version_option() @click.argument('infile', type=click.File()) def main(infile): click.echo(infile.read()) 1 2 3 4 5 6 7
- 16. """Foobar Usage: foobar (-h | --help | --version) foobar [-s | --silent] <file> foobar [-v | --verbose] <file> Positional arguments: file target file path name Optional arguments: -h, --help show this help message and exit -s, --silent don't show progress output -v, --verbose explain progress verbosely --version show program's version number and exit """ from docopt import docopt from . import __version__ def parse_arguments(): args = docopt(__doc__, version=__version__) return dict( file=args['<file>'], silent=args['-s'] or args['--silent'], verbose=args['-v'] or args['--verbose'], ) 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 Docopt
- 17. $ copier gh:painless-software/python-cli-test-helpers pycon-italia-cli 🎤 engine (Use arrow keys) » Argparse Click Docopt ... Demo 🐍 ✨ ✨ https://python-cli-test-helpers.readthedocs.io
- 18. Thank you! for your precious time Painless Software Less pain, more fun. Most images taken from Wikipedia (CC-SA) Alberto Sordi animated GIF stolen from giffetteria.it