Flask CROS(Cross-Origin Resource Sharing) decorator simplified

cros.py

import datetime
import functools

from flask import (
    current_app,
    make_response,
    request
)


def cros(origin, methods=None, max_age=3600):
    methods = methods or ['OPTIONS', 'GET', 'POST', 'PUT', 'DELETE']
    methods = ', '.join(m.upper() for m in methods)

    if isinstance(max_age, datetime.timedelta):
        max_age = max_age.total_seconds()

    def decorator(func):
        @functools.wraps(func)
        def wrapped(*args, **kwargs):
            if request.method == 'OPTIONS':
                resp = current_app.make_default_options_response()
                resp.headers.pop("allow")
            else:
                resp = make_response(func(*args, **kwargs))

            resp.headers.extend({
                "Access-Control-Allow-Methods": methods,
                "Access-Control-Allow-Origin": origin,
                "Access-Control-Max-Age": max_age,
                "Access-Control-Allow-Headers": "Content-Type",
            })
            return resp
        return wrapped
    return decorator