Decorators with parameters

 

https://stackoverflow.com/a/25827070

 

Transleates decorator without parameters

@decorator
def foo(*args, **kwargs):
    pass

translates to 

foo = decorator(foo)

 

Transleates decorator with parameters

@decorator_with_args(arg)
def foo(*args, **kwargs):
    pass

translates to

foo = decorator_with_args(arg)(foo)

decorator_with_args(arg) 은 function 을 파라미터로 받는 함수(decorator without parameters)가 되어야 한다.

 

코드

import functools


def my_deco(msg):
    def inner(f):
        @functools.wraps(f)
        def wrapper(*args, **kwargs):
            print(f'Start {msg}')
            r = f(*args, **kwargs)
            print('End')
            return r

        return wrapper

    return inner


@my_deco("Hello")
def my_square(x):
    return x ** 2


if __name__ == '__main__':
    result = my_square(3)
    print(result)


# Start Hello
# End
# 9

 

 

참고

type signature in docorator functions

import functools
from time import perf_counter
from typing import Callable, Any


def benchmark(f: Callable[..., Any]) -> Callable[..., Any,]:
    @functools.wraps(f)
    def wrapper(*args: Any, **kwargs: Any):
        start_time = perf_counter()
        g = f(*args, **kwargs)
        end_time = perf_counter()
        run_time = end_time - start_time
        print(f"Execution of {f.__name__} took {run_time:.2f} second")
        return g

    return wrapper