06. Using the Authorization Service.md

Using the Authorization Service

This section will teach you how to use the AuthorizationService to its full extend.

Injecting the Authorization Service

Using initializers

To automatically inject the authorization service into your classes, you can implement the AuthorizationServiceAwareInterface and use the trait, as shown below:

namespace YourModule;

use ZfcRbac\Service\AuthorizationServiceAwareInterface;
use ZfcRbac\Service\AuthorizationServiceAwareTrait;

class MyClass implements AuthorizationServiceAwareInterface
{
    use AuthorizationServiceAwareTrait;

    public function doSomethingThatRequiresAuth()
    {
        if (! $this->getAuthorizationService()->isGranted('deletePost')) {
            throw new UnauthorizedException('You are not allowed !');
        }

        return true;
    }
}

Then, registers the initializer in your config (it is not by default):

class Module
{
    // getAutoloaderConfig(), etc...

    public function getServiceConfig()
    {
        return [
			'initializers' => [
			    'ZfcRbac\Initializer\AuthorizationServiceInitializer'
			]
        ];
    }
}

While initializers allow rapid prototyping, it can leads to more fragile code. We'd suggest using factories.

Using Factories

You can inject the AuthorizationService in your factories by using Zend's ServiceManager. The AuthorizationService is known to the ServiceManager as 'ZfcRbac\Service\AuthorizationService'. Here is a classic example for injecting the AuthorizationService:

YourModule/Module.php

class Module
{
    // getAutoloaderConfig(), etc...

    public function getServiceConfig()
    {
        return [
            'factories' => [
                 'MyService' => function($sm) {
                     $authService = $sm->get('ZfcRbac\Service\AuthorizationService')
                     return new MyService($authService);
                 }
            ]
        ];
    }
}

Using Zend\DI

DI is a great way for prototyping, getting results fast and maintaining a flexible structure. However it adds overhead and can get very slow. Unless you are using a compiler it is not recommended for production. Here's how you enable Zend\DI to inject the AuthorizationService in MyClass:

YourModule/Module.php

namespace YourModule;

class Module
{
    // getAutoloaderConfig(), etc...

    public function getConfig()
    {
        return [
		    'di' => [
		        'definition' => [
		            'class' => [
		                __NAMESPACE__ . '\MyClass' => [
		                    'setAuthorizationService' => [
		                        'required' => true
		                    ]
		                ]
		            ]
		        ]
	        ]
        ];
    }
}

Permissions and Assertions

Since you now know how to inject the AuthorizationService, let's use it!

One of the great things the AuthorizationService brings are assertions. Assertions get executed if the identity in fact holds the permission you are requesting. A common example is a blog post, which only the author can edit. In this case, you have a post.edit permission and run an assertion checking the author afterwards.

Defining assertions

The AssertionPluginManager is a great way for you to use assertions and IOC. You can add new assertions quite easily by adding this to your module.config.php file:

return [
    'zfc_rbac' => [
        'assertion_manager' => [
            'factories' => [
                'MyAssertion' => 'MyAssertionFactory'
            ]
        ]
    ]
];

Defining the assertion map

The assertion map can automatically map permissions to assertions. This means that every times you check for a permission with an assertion map, you'll include the assertion in your check. You can define the assertion map by adding this to your module.config.php file:

return [
    'zfc_rbac' => [
        'assertion_map' => [
            'myPermission' => 'myAssertion'
        ]
    ]
];

Now, everytime you check for myPermission, myAssertion will be checked as well.

Checking permissions

So let's check for a permission, shall we?

$authorizationService->isGranted('myPermission');

That was easy, wasn't it?

isGranted checks if the current identity is granted the permission and additionally runs the assertion that is provided by the assertion map.

Defining additional permissions

But what if you don't want to use the assertion map? That's quite easy as well!

Here are four use cases on how you can work without the assertion map:

Disable the assertion:

$authorizationService->setAssertion('myPermission', null);
$authorizationService->isGranted('myPermission');

Callback assertion:

$something = true;

$authorizationService->setAssertion(
   'myPermission',
   function(AuthorizationService $authorization, $context = true) use ($something) {
      return $something === $context
   }
);

$authorizationService->isGranted('myPermission'); // returns true, when the identity holds the permission `myPermission`

Object implementing AssertionInterface:

$context = true;

$authorizationService->setAssertion('myPermission', new MyAssertion($foo, $bar));
$authorizationService->isGranted('myPermission', $context);

Using the AssertionPluginManager:

$context = true;
$authorizationService->setAssertion('myPermission', 'MyAssertion');
$authorizationService->isGranted('myPermission', $context);

Please note: The context parameter is optional!

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