Rhebok - A hierarchical, asynchronous role based access control (RBAC) module

Overview

This module works by defining a hierarchy of roles and capabilities and checking to see if a role possesses a certain capability. This allows you to determine whether a user should have access to a given resource or operation. The module is written in Typescript and compiles to commonjs.

This module is in beta. The API could change prior to 1.0 release.

Changelog

• 0.2.0: Instead of extending the Cap class, you should now create a class that implements ICap. See the example.spec.ts file for implementation details.

Install

npm install rhebok

Sample Code

Code samples demonstrating the usage of this module are available here.

Objects

Role

Accepts name and params.

Important The Role name must be unique within your role hierarchy. To ensure that you haven't used a role name twice, you can chain the validate() method to the end of your topmost role. This will run a recursive check and throw an error if a duplicate role name has been found. While you do not have to call this method, keep in mind that accidentally re-using a role name could result in a user gaining elevated access.

const SimpleRoleSchema = new Role(
	 'logged-out',
	{
	    caps: [
	      new HasCap('user:create')
	    ],
	    children: [
		    new Role(
			    'logged-in',
			    {
				    caps: [
					    new HasCap('event:create'),
					    new ConditionalCap(
						    'event:update',
						    {
							    if: async (context: any) => {
									return (context.eventOwnerId === context.userId);
								}
							}
					    )
				    ]
				}
			)
		]
	}
 ).validate();

Methods

Can

Accepts a role name, capability name and a context object. The context object is passed into any ConditionalCap to help it decide if the role should pass the capability check. This method returns a promise which resolves to true if the role has the capability.

SimpleRoleSchema.can(
	'logged-in',
	'event:update', 
	{ 
		userId: 5, 
		eventOwnerId: 6
	}
);

HasCap

Accepts name. If a role has this capability then the role is deemed to be authorized.

new HasCap('event:create')

ConditionalCap

Accepts a name and params. If a role has this capability, then the function assigned to the if attribute of params is called. The if function should return a promise. If that promise resolves with true, then the role is deemed authorized.

new ConditionalCap(
    'event:update',
    {
	    if: async (context: any) => {
			return (context.eventOwnerId === context.userId);
		}
	}
)

Extending Roles and Capabilities

Extending Roles

You may wish to extend the Role object in your application with a thin wrapper. This will provide two benefits:

1. You can use types for your roles and the context parameter which gives you the benefits of type checking in Typescript.
2. You can encapsulate logic for asynchronously retrieving a users role. This is especially helpful when the users role depends on the authorization context (i.e. the users role depends on the particular object they are trying to access).

The examples folder shows how to extend roles and capabilities with custom typings.