短縮 URL 展開してくれる君

main.py

import sys
import requests


# default arg is the demo url
def req(url='https://bit.ly/1cY78RZ'):
    res = requests.head(url)
    if int(res.status_code / 100) != 3:
        return res.url
    else:
        return req(res.headers['Location'])

def main():
    if len(sys.argv) == 2:
        print(req(sys.argv[1]))
    else:
        print(req())

if __name__ == '__main__':
    main()