Esrapgra

The opposite of argparse. Converts function arguments to command-line arguments.

Installation

pip install esrapgra

From source

pip install git+https://github.com/audy/esrapgra

Overview

So you want to call wget from Python, mapping Python variables to command-line arguments:

wget \
   http://example.com/file.zip \
   --directory-prefix=/path/to/directory \
   --retry-connrefused \
   --waitretry=5 \
   --tries=3

This often gets messy if you need to interpolate values into the arguments or map Python logic into command logic:

args = [
    "http://example.com/file.zip",
    "--directory-prefix",
    directory_prefix,
    f"--tries={tries}"
]

if retry_connrefused:
    args.append("--retry-connrefused")


subprocess.check_output(["wget"] + args)

With Esrapgra (if you can remember how to spell it), this becomes a nice function invocation:

es = Esrapgra(kwargs_last=True)

args = es.lex_arguments(
    "http://example.com/file.zip",
    directory_prefix="/path/to/directory",
    retry_connrefused=True,
    waitretry=5,
    tries=3
)

subprocess.check_output(["wget"] + args)

The following things are happening:

• String arguments are automatically escaped and quote to protect against shell-escape attacks
• Boolean arguments are automatically turned into boolean flags (e.g., retry_connrefused=True turns into --retry-connrefused and retry_connrefused=False turns into nothing)
• Numeric flags are automatically converted into strings

Examples

Basic Initialization

You can initialize the Esrapgra object with default parameters:

esrap = Esrapgra()

Custom Separator

Customize the separator between words in keyword arguments:

# Using underscores as separators
esrap = Esrapgra(separator="_")

# Example usage
esrap.lex_arguments(test_argument="test")  # Output: ['--test_argument="test"']

Custom Prefix

Define a custom prefix for the keyword arguments:

# Using a single hyphen as a prefix
esrap = Esrapgra(prefix="-")

# Example usage
esrap.lex_arguments(test_argument="test")  # Output: ['-test_argument="test"']

Keyword Arguments Position

Control the position of keyword arguments relative to positional arguments:

# Putting keyword arguments before positional arguments
esrap = Esrapgra(kwargs_last=False)

# Example usage
esrap.lex_arguments(
    "first_arg",
    test_argument="test"
)
# Output: ['-test_argument="test"', 'first_arg']

Quoting Strings

You can enable or disable the quoting of strings as per your needs:

# Disabling quoting of strings
esrap = Esrapgra(quote_strings=False)

# Example usage

# Adjust the expected output based on the implementation of `lex_arguments`
esrap.lex_arguments(test_argument="test")