A utility for implementing behavior-based authorization logic.
import {legally} from 'legallycan';
legally(subject).can(DoSomething).check()
.then(() => {
// subject can do something.
})
.catch(err => {
// subject cannot do something.
});// User class
class User {
readonly name: string;
readonly isAdmin: boolean;
constructor(name: string, isAdmin: boolean) {
this.name = name;
this.isAdmin = isAdmin;
}
equals(target: User): boolean {
return this.name === target.name;
}
}
// A legal
class ViewProfile extends Legal<User> {
async check(): Promise<void> {
const target = this.options.of as User;
if (!target || !(target instanceof User)) {
throw new Illegal('No target');
}
if (this.principal.equals(target)) {
return; // User can view his own profile.
}
if (this.principal.isAdmin) {
return; // Administrator can do anything.
}
throw new Illegal('Prohibited');
}
}
const adminUser = new User('Admin', true);
const normalUserA = new User('User A', false);
const normalUserB = new User('User B', false);
// No error, because a user can view profile of himself
await legally(normalUserA).can(ViewProfile).of(normalUserA).check()
// Error, because a user cannot view any profile of others
await legally(normalUserA).can(ViewProfile).of(normalUserB).check()
// No error, because administrator can view anything
await legally(adminUser).can(ViewProfile).of(normalUserA).check()MIT
(c) Keisuke Yamamoto 2019
https://github.com/yamamotok