is there any mothod to Enforce Exact Case-Sensitive Flag Matching with argparse in Python

Question

I am working on a Python script using argparse library to handle command-line arguments. I want to enforce strict and case sensitive match for a specific flag. such as --signup , without allowing any other variations, shorthand or incorrect spellings and any value afterwards.

I have tried using a custom action along with the nargs parameter, but I'm facing challenges to achieve desired outcome. Here is simplified version of my code:

import argparse

class ValidateSignupAction(argparse.Action):
    def __call__(self, parser, namespace, values, option_string=None) -> None:
        if values != ['--signup']:
            parser.print_help()
            parser.exit(1) 
        setattr(namespace, self.dest, values)

def register_args():
    parser = argparse.ArgumentParser()
    parser.add_argument("--signup", action=ValidateSignupAction, help="Initiate user signup process", required=True)
    register_args = parser.parse_args()
    return register_args

Code is not producing the desired outcome. When I provide command python register.py --signup or python register.py --singup , It prints the help menu for both command-lines. I want it to return True if python register.py --signup without any value after --signup.

Running this script:

> python .\register.py --signup

Prints:

usage: register.py [-h] --signup SIGNUP
register.py: error: argument --signup: expected one argument

Is there a way to achieve this level of strict match for the --signup flag using argparse alone? Or should I consider an alternative approach?

Any suggestion or guidance would be greatly helpful. Thankyou in Advance for you help.

Additional Notes:

• I have tried using choices parameter, but it does not seem to work for my use case.

• I am aiming to enforce the exact flag with no shorthand or variations, even in different letter cases.

Answer 1

Testing in an ipython session:

In [128]: parser = argparse.ArgumentParser(allow_abbrev=False)
In [129]: parser.add_argument('--signup', action='store_true');

Correct use:

In [130]: parser.parse_args('--signup'.split())
Out[130]: Namespace(signup=True)

attempting to add a string

In [131]: parser.parse_args('--signup foobar'.split())
usage: ipython [-h] [--signup]
ipython: error: unrecognized arguments: foobar
SystemExit: 2

attempting an abbreviation:

In [132]: parser.parse_args('--sign'.split())
usage: ipython [-h] [--signup]
ipython: error: unrecognized arguments: --sign
SystemExit: 2