Python decorator with arguments

try_decorators_args.py

from functools import wraps


def admin_only(*fargs):
    def _admin_only(func):
        @wraps(func)
        def _check_admin(*args, **kwargs):
            self = args[0]
            if not self.user.isAdmin:
                raise RuntimeError("ERROR: admin only")
            elif not set(fargs) <= set(self.user.adminPrivileges):
                    raise RuntimeError("ERROR: insufficient privileges")
            return func(*args, **kwargs)
        return _check_admin
    return _admin_only


class User(object):

    def __init__(self, is_admin, admin_privileges=None):
        self._is_admin = is_admin
        self._admin_privileges = admin_privileges or []

    @property
    def isAdmin(self):
        return self._is_admin

    @property
    def adminPrivileges(self):
        return self._admin_privileges

    def __repr__(self):
        return "User(admin=%r, privileges=%r)" % (
            self.isAdmin, self.adminPrivileges
        )


class Consumer(object):

    def __init__(self, user):
        self.user = user

    @admin_only()
    def m1(self):
        """m1, only for admins"""
        return "m1"

    @admin_only("Foo")
    def m2(self):
        """m2, only for Foo-enabled admins"""
        return "m2"

    @admin_only("Foo", "Bar")
    def m3(self):
        """m3, only for Foo- and Bar-enabled admins"""
        return "m3"


def main():
    all_users = [
        User(True, ["Foo", "Bar"]),
        User(True, ["Foo"]),
        User(True, ["Bar"]),
        User(False),
    ]
    for user in all_users:
        consumer = Consumer(user)
        print consumer.m1.__doc__
        try:
            print "%r: %r" % (user, consumer.m1())
        except RuntimeError as e:
            print "%r: %r" % (user, e)
        print consumer.m2.__doc__
        try:
            print "%r: %r" % (user, consumer.m2())
        except RuntimeError as e:
            print "%r: %r" % (user, e)
        print consumer.m3.__doc__
        try:
            print "%r: %r" % (user, consumer.m3())
        except RuntimeError as e:
            print "%r: %r" % (user, e)
        print


if __name__ == "__main__":
    main()

% python try_decorators_args.py
m1, only for admins
User(admin=True, privileges=['Foo', 'Bar']): 'm1'
m2, only for Foo-enabled admins
User(admin=True, privileges=['Foo', 'Bar']): 'm2'
m3, only for Foo- and Bar-enabled admins
User(admin=True, privileges=['Foo', 'Bar']): 'm3'

m1, only for admins
User(admin=True, privileges=['Foo']): 'm1'
m2, only for Foo-enabled admins
User(admin=True, privileges=['Foo']): 'm2'
m3, only for Foo- and Bar-enabled admins
User(admin=True, privileges=['Foo']): RuntimeError('ERROR: insufficient privileges',)

m1, only for admins
User(admin=True, privileges=['Bar']): 'm1'
m2, only for Foo-enabled admins
User(admin=True, privileges=['Bar']): RuntimeError('ERROR: insufficient privileges',)
m3, only for Foo- and Bar-enabled admins
User(admin=True, privileges=['Bar']): RuntimeError('ERROR: insufficient privileges',)

m1, only for admins
User(admin=False, privileges=[]): RuntimeError('ERROR: admin only',)
m2, only for Foo-enabled admins
User(admin=False, privileges=[]): RuntimeError('ERROR: admin only',)
m3, only for Foo- and Bar-enabled admins
User(admin=False, privileges=[]): RuntimeError('ERROR: admin only',)