Custom decorators

[andrijan]

Hi there!

I'm trying to make a custom decorator, but for some reason the code never enters the wrapper function. Can you see an obvious mistake I making here?

ROLES = {
    "user": 1,
    "limited": 2,
    "admin": 3,
    "superadmin": 4,
}
NOT_AUTHORISED = 9999


def min_role(role):
    def decorator(func):
        @wraps(func)
        def wrapper(request, *args, **kwargs):
            if ROLES[request.user.role] < ROLES.get(role, NOT_AUTHORISED):
                return 403, None
            return func(request, *args, **kwargs)

        return wrapper

    return decorator

@api.post(
    "/locations",
    url_name="location-create",
    response={201: LocationSchemaOut, 403: None},
)
@min_role("superadmin")
def create_location(request, location: LocationSchemaIn):
    ...

[vitalik]

@andrijan

well I simplified a bit your version to pass role as parameters - and it works:

ROLES = {
    "user": 1,
    "limited": 2,
    "admin": 3,
    "superadmin": 4,
}
NOT_AUTHORISED = 9999


def min_role(role):
    def decorator(func):
        @wraps(func)
        def wrapper(request, *args, **kwargs):
            user_role = int(request.GET.get('role', 0))
            if user_role < ROLES.get(role, NOT_AUTHORISED):
                return 403, None
            return func(request, *args, **kwargs)

        return wrapper

    return decorator


@api.get(
    "/locations",
    url_name="location-create",
    response={201: str, 403: None},
)
@min_role("superadmin")
def create_location(request, location: int, role: int):
    return 201, 'success'

http://localhost:8000/api/locations?location=1&role=1 --> 403 (empty)
http://localhost:8000/api/locations?location=1&role=6 --> 201 ("success")

Maybe it's wraps function ? did you import it from functools ?

from functools import wraps

[andrijan]

Ahh, I now see my issue. The data validation is being executed before my decorator.

I would have thought that the ideal way was to check for the role (and return 403) before validating my inputs. Is there way to make my decorator execute before the validations?

I guess I'm having similar issues as this one #156