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Python GUI and CLI applications for Oil and Gas
^ Show one way to expand CLI script to support CLI, lib, GUI, exe
- Walk-through this process showing the key changes at each step
import sys
lines = 0
words = 0
with open(sys.argv[1], 'rb') as file_obj:
for line in file_obj:
lines += 1
words += len(line.split())
print(f'{lines} {words}')^ Clone of Unix wc to count words/lines in file ^ Limitations: ^ - No help ^ - Not extensible ^ - args vs. real work ^ - Reuse by other devs ^ - Requires Python ^ - Python 2/3 discussion
^ - Parsing args vs. reading file
- Preached alot with GUIs
- sys.argv is user interface and counting lines/words is action
def cli():
"""
Parse sys.argv and return dictionary of arguments/configuration
"""
pass
def get_file_info(file_):
"""
Return lines/words in file
"""
pass
if __name__ == '__main__':
file_ = cli()
print(get_file_info(file_))^ - Code reuse
- Only CLI interface knows of sys.argv
- Only prints when run as script
file_info = collections.namedtuple('file_info', 'lines words')
def get_file_info(file_):
lines = 0
words = 0
with open(file_, 'rb') as file_obj:
for line in file_obj:
lines += 1
words += len(line.split())
return file_info(lines, words)def cli():
parser = argparse.ArgumentParser(prog='pywc')
parser.add_argument('arg', action='store',
help='File or directory to count lines/words for')
parser.add_argument('-w', dest='count_words', action='store_true',
default=False, help='Show number of words in file(s)')
parser.add_argument('-l', dest='count_lines', action='store_true',
default=False, help='Show number of lines in file(s)')
# Using vars() to turn namespace object returned by parse_args() into a
# dict.
args = vars(parser.parse_args())
# Mimic wc command by printing both of these if there are no other
# arguments
if not args['count_words'] and not args['count_lines']:
args['count_words'] = True
args['count_lines'] = True
return args^ - Built-into stdlib
- Multiple arguments
- Automatic help
- vars() hides CLI detail from other code
- setup.py
- pywc/
- api.py
- __init__.py
- __main__.py
^ - setup.py -> pip install
- api.py = workhorse
__init__.py= python package__main__.py` strange name, see why later
from setuptools import setup, find_packages
setup(
name='pywc',
version='1.0.0',
packages=find_packages(),
)^ - pip install like pypi
from .api import get_file_info
def cli():
"""
Parse sys.argv and return dictionary of arguments
"""
pass
def main():
args = cli()
file_info = get_file_info(args['file'])
if args['count_lines']:
print(f' {file_info.lines}', end='')
if args['count_words']:
print(f' {file_info.words}', end='')
print(f' {args['file']}')
if __name__ == '__main__':
main()^ - Same as original script w/o 'real' code
- Separation of concerns: launch vs. library
mainkeeps var/name pollution if we import
^ - Locked away in pkg
- No outside interface
- Support using from Python, but no CLI
from setuptools import setup
setup(
name='pywc',
version='1.0.0',
packages=find_packages(),
entry_points={
'console_scripts': [
'pywc = pywc.__main__:cli'
]
},
)^ - Looks and acts like prev single-file script
- Only when installed
- Requires users know about pip
^ - Closer interface to orig script
- Supports
__main__and__main__.py - No need to install
- Package equivalent of
__init__ == __main__
|
|
|
|---|---|---|
| http.server | json.tool | pdb |
| timeit | cProfile | unittest |
| doctests | tarfile | zipapp |
| zipfile | webbrowser | base64 |
| calendar | sysconfig |
^ Not all use main, but work with -m
- zipapp: zip directory and run
__main__.pywo install - sysconfig: how python binary was compiled
from gooey import Gooey
@Gooey
def cli():
parser = argparse.ArgumentParser(
prog='pywc',
description='Count lines/words in files or directory')
parser.add_argument(
'arg', action='store',
help='File or directory to count lines/words for')
...^ - Works magic on argparse
- Uses wx
- Introspect and maps argparse actions/types to GUI elements
- Downside: Forces GUI unless
--ignore-gooey
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def cli(allow_gui_option=True):
"""
Add --gui option to call gui()
"""
pass
def gui():
# Gooey doesn't like functools.partial
def cli_only():
return cli(allow_gui_option=False)
return Gooey(cli_only, program_name='pywc',
show_success_modal=False)from setuptools import setup
setup(
entry_points={
'console_scripts': [
'pywc = pywc.__main__:cli'
]
'gui_scripts': [
'pywcg = pywc.__main__:gui'
]
},
)^ Pure magic ^ Supports PyQt, numpy, wx, ... ^ Windows, Linux, OSX
^ - Don't need anything installed, including Python!
- setup.py
- cli.py
- gui.py
- pywc/
- api.py
- __init__.py
- __main__.py
^ - Pyinstaller 👎 relative imports
- 2 exes = 2 entry points
- Shared via
__main__.py
from pywc.__main__ import cli
if __name__ == '__main__':
cli()from pywc.__main__ import gui
if __name__ == '__main__':
gui()^ - --onefile
--additional-hooks-dir
^ - console_scripts
gui_scripts
^ - Benefits
-msupport- Single-file entry point
- Commonly used pattern
pywc
pywc --gui
pywcg
python -m pywc
python -m pywc --gui
pywc.exe
pywcg.exe
python cli.py
python cli.py --gui
python gui.py
pywcg --gui
python gui.py --gui
pywcg.exe --gui
^ - Quirk of Gooey introspection
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