Question

I’m trying to create an authorization scheme for my ASP.NET MVC application where an Enum is used to set permissions. For example:

[Flags]
enum Permissions
{
    ReadAppointments = 1,
    WriteAppointments = 2 | ReadAppointments,
    ReadPatients = 4,
    WritePatients = 8 | ReadPatients,
    ReadInvoices = 16,
    WriteInvoices = 32 | ReadInvoices
    ...
}

But I don’t really like that because it really doesn’t make it clear that Write always includes Read.

I then realized that a requirement would be that a user might have NO access to, for example, Appointments.

Essentially, I’d want a “bitfield” with 3 states: none, readonly, full (read/write). I’d like to still use an enum bitfield since it’s easy to store in a DB (as an int). Also it’s very easy to see if a permission is set.

Does anyone have any idea how this could be easily accomplished using an Enum… or am I going in the completely wrong direction?

EDIT: I’m really trying to avoid storing permission definitions in the DB since I really want things to be changeable without having to modify much on the DB end. It’d be really nice to know how a large scale application would do this.

Answer 1

I would probably do this as separate fields for each area (Invoices. Patients, Appointments) using a single enum to cover each of them.

enum Permission { None, ReadOnly, ReadWrite };

To me, this is easier to understand and manage, and it doesn’t combine a bunch of unrelated things (I should say “seemingly unrelated”, since I don’t know anything about your app).