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FroshKiller
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I'm creating a new-style class in Python 3.6. I've defined a property (with the @property decorator) called interaction_id. This is a string value with a maximum length of 100.

Originally, I had naively written the setter like this:

@interaction_id.setter
def interaction_id(self, value: str):
    if len(value) > 100:
        raise ValueError("Value may not exceed 100 characters.")

    self._interaction_id = value

However, I have other string properties with their own limits, and I want to avoid writing a bunch of fucking boilerplate. I thought it'd be nice to have a decorator like this:

@interaction_id.setter
@max_length(100)
def interaction_id(self, value: str):
    self._interaction_id = value

My max_length function looks like this:

def maxlength(length):
    def maxlength_decorator(func):
        def wrapper(*args, **kwargs):
            if len(args[1]) > length:
                raise ValueError("Value must not exceed {} characters".format(length))
            return func(*args, **kwargs)
        return wrapper
    return maxlength_decorator

This looks like it's a pretty standard pattern for decorators that take arguments, but is there a better method for setter validation that doesn't involve installing a new module? I don't find the decorator definition very readable (although I doubt anyone's going to look at it).

8/13/2018 5:46:49 PM

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