Authorization Decorators

Authorization Decorator

Syntax:

• @authorize({resource: 'order', scopes: ['create']})

The authorization decorator is used to provide access control metadata. As part of the component @loopback/authorization, it is applied to controller members and is used to specify who can perform which operations to the protected resource.

The @authorize decorator takes in an object in type AuthorizationMetadata. The syntax example specifies the resource and scopes. A full list of the available configuration properties are:

• allowedRoles/deniedRoles: Define the ACL based roles. It should be an array of strings.
• voters: Supply a list of functions to vote on a decision about a subject’s accessibility. A voter is a method or class level authorizer.
• resource: Type of the protected resource, such as customer or order.
• scopes: An array of the operations against the protected resource, such as get or delete.
• skip: A boolean value to mark an endpoint/a controller skips the authorization.

Method Level Decorator

You can decorate a controller method with @authorize like the following example. It specifies every user can create a new order.

class OrderController {
  orders: Order[] = [];
  // User with role 'everyone' can create new order
  @authorize({
    allowedRoles: ['everyone'],
    scopes: ['create'],
    resource: 'order',
  })
  async placeOrder(order: Order) {
    order.id = `order-${this.orders.length + 1}`;
    this.orders.push(order);
    return order.id;
  }
}

Class Level Decorator

To configure a default authorization for all methods within a class, @authorize can also be applied at the class level. In the code below, remote method numOfViews() is protected with ADMIN role, while authorization for remote method hello() is skipped by the use of @authorize.skip().

@authorize({allowedRoles: ['ADMIN']})
export class MyController {
  @get('/number-of-views')
  numOfViews(): number {
    return 100;
  }

  @authorize.skip()
  @get('/hello')
  hello(): string {
    return 'Hello';
  }
}

Shortcuts

We have a list of shortcut decorators to quickly configure the metadata. For instance, authorize.allow(...roles: string[] is short for authorize({allowedRoles: roles});

You can find all the shortcuts in the @authorize() API documentation.