argparser-adapter 1.4

Add argparser argument based on object heuristics

This package provides automatic adding of arguments to an argparser. ArgumentParser based on a simple method naming convention.

Basic Usage

Write your class with methods you wish called from a command line starting with a given prefix. Create an ArgparserAdapter, passing your object as a constructor. Methods starting with a the specified prefix, do_ by default, will be added to an argparser via the register call as – arguments. After parsing, call_specified_methods will call methods specified on command. ArgparseAdapter will attempt to convert command line strings to appropriate types if Python type hints are provided.

Example

import argparse
from ipaddress import IPv4Address
from argparse_adapter.argparse_adapter import ArgparserAdapter

class Something:

    def do_seven(self)->int:
        print(7)
        return 7


    def do_double(self,x):
        """double a number"""
        print(2*int(x))

    def do_triple(self,x:int):
        print(3*x)

    def do_sum(self,x:int,y:int):
        """sum arguments"""
        print(x + y)

    def do_ipv4address(self,x:IPv4Address):
        print(x)


def main():
    something = Something()
    adapter = ArgparserAdapter(something)
    parser = argparse.ArgumentParser()
    adapter.register(parser)
    args = parser.parse_args()
    adapter.call_specified_methods(args)

Note the do_double will receive a string and must convert it to an integer. The type hint in do_triple ensures the argument will be an integer.

The resulting argument argparser help is:

usage: objecttest.py [-h]
                     (--double x | --ipv4address x | --seven | --sum x y | --triple x)

optional arguments:
  -h, --help       show this help message and exit
  --double x       double a number
  --ipv4address x
  --seven
  --sum x y        sum arguments
  --triple x

Docstrings, if present, become help arguments.

Advanced usage

When type conversion fails, the method

def param_conversion_exception(self, e: Exception, method_name: str, parameter_name: str, parameter_type: type,
                               value: str) -> Any:

is called. The default behavior is to raise a ValueError exception including the method and parameter names, the value passed and the original exception message. This method is provided for subclasses to override, if desired. An implementation should raise an Exception or return a suitable parameter for calling method_name.

Alternative packages

More complete packages are available for this purpose, such as Click. This implementation is intended to be simple, lightweight and easy to use.