Python Function Decorator Example #1

decorator_response_ok.py

from urllib.parse import urljoin

import urllib3
from urllib3.exceptions import HTTPError


def response_ok(func):
    def validate(*args, **kwargs):
        result = func(*args, **kwargs)
        if result.status != 200:
            raise HTTPError(f'Request Failed with status code {result.status}')
        return result

    return validate


@response_ok
def fetch(path):
    with urllib3.PoolManager() as http:
        return http.request('GET', path)


if __name__ == '__main__':
    api = 'http://httpbin.org'
    url = urljoin(api, 'ip')  # 존재하는 URL 입니다. 200 응답을 기대합니다
    wrong_url = urljoin(api, 'pi')  # 존재하지 않는 URL 입니다. 404 응답을 기대합니다
    fetch(url).data.decode()  # '{\n  "origin": "1.2.3.4"\n}\n'
    fetch(wrong_url).data.decode()  # urllib3.exceptions.HTTPError: Request Failed with status code 404

timer_decorator.py

import functools
import time


def timer(func):
    @functools.wraps(func)
    def wrapper(*args, **kwargs):
        start = time.time()
        result = func(*args, **kwargs)
        print(f'{func.__name__} took {round((time.time() - start), 4)} seconds')
        return result

    return wrapper


# timer 데코레이터 적용
@timer
def huge_add(a, b):
    result = a + b
    time.sleep(1)
    return result


@timer
def huge_subtract(a, b):
    result = a + b
    time.sleep(1)
    return result


@timer
def huge_multiply(a, b):
    result = a * b
    time.sleep(1)
    return result


if __name__ == '__main__':
    huge_number = 10e8
    huge_add(huge_number, huge_number)
    huge_subtract(huge_number, huge_number)
    huge_multiply(huge_number, huge_number)

# 출력, 이제는 간편하게 호출된 함수 이름도 확인할 수 있습니다
# huge_add took 1.0037 seconds
# huge_subtract took 1.0044 seconds
# huge_multiply took 1.0028 seconds

timer_without_decorator.py

import time


# 시작, 종료 시간을 체크해서 프린트 하는 코드를 함수안에 반영합니다.
def huge_add(a, b):
    start = time.time()
    result = a + b
    time.sleep(1)
    print(f'add Elapsed time: {round((time.time() - start), 4)} seconds')
    return result


# huge_add 와 같은 일을 하는 코드가 반복됩니당
def huge_subtract(a, b):
    start = time.time()
    result = a + b
    time.sleep(1)
    print(f'subtract Elapsed time: {round((time.time() - start), 4)} seconds')
    return result


# 같은 일을 하는 코드가 반복됩니당
def huge_multiply(a, b):
    start = time.time()
    result = a * b
    time.sleep(1)
    print(f'multiply Elapsed time: {round((time.time() - start), 4)} seconds')
    return result


if __name__ == '__main__':
    huge_number = 10e8
    huge_add(huge_number, huge_number)
    huge_subtract(huge_number, huge_number)
    huge_multiply(huge_number, huge_number)

# 출력
# add Elapsed time: 1.0039 seconds
# subtract Elapsed time: 1.0048 seconds
# multiply Elapsed time: 1.0048 seconds