Introduction to Zend\Permissions\Rbac¶
The Zend\Permissions\Rbac component provides a lightweight role-based access control implementation based around PHP 5.3’s SPL RecursiveIterator and RecursiveIteratorIterator. RBAC differs from access control lists (ACL) by putting the emphasis on roles and their permissions rather than objects (resources).
For the purposes of this documentation:
- an identity has one or more roles.
- a role requests access to a permission.
- a permission is given to a role.
Thus, RBAC has the following model:
- many to many relationship between identities and roles.
- many to many relationship between roles and permissions.
- roles can have a parent role.
The easiest way to create a role is by extending the abstract class Zend\Permission\Rbac\AbstractRole or simply using the default class provided in Zend\Permission\Rbac\Role. You can instantiate a role and add it to the RBAC container or add a role directly using the RBAC container addRole() method.
Each role can have zero or more permissions and can be set directly to the role or by first retrieving the role from the RBAC container. Any parent role will inherit the permissions of their children.
In certain situations simply checking a permission key for access may not be enough. For example, assume two users, Foo and Bar, both have article.edit permission. What’s to stop Bar from editing Foo’s articles? The answer is dynamic assertions which allow you to specify extra runtime credentials that must pass for access to be granted.