bug #1614 Use ServiceIterator in Security provider for voters (hkdobrev)

This PR was squashed before being merged into the 2.3.x-dev branch (closes #1614).

Discussion
----------

Use ServiceIterator in Security provider for voters

Fixes #1530.

Commits
-------

e2c48152 Use ServiceIterator in Security provider for voters

doc/providers/security.rst

@@ -686,6 +686,32 @@ Symfony `cookbook`_.
     providers. :doc:`How to Create a Custom Authentication System with Guard
     </cookbook/guard_authentication>`
 
+Using Voters to check user permissions
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+See the `Security component documentation on voters <http://symfony.com/doc/current/security/voters.html>`_.
+
+By default Silex includes the role hierarchy and authenticated voters.
+If you want to add a custom voter, you need to register it as a service and extend ``security.voter_services``.
+
+.. code-block:: php
+
+    $app['custom_voter'] = function () {
+        return MyCustomVoter();
+    };
+
+    $app->extend('security.voter_services', function (array $voters) {
+        $voters[] = 'custom_voter';
+
+        return $voters;
+    });
+
+.. note::
+    Using the above approach with the service names circular references are avoided
+    and you can use the ``AccessDecisionManager`` in your custom voter
+    to `check for roles inside a voter
+    <http://symfony.com/doc/current/security/voters.html#checking-for-roles-inside-a-voter>`_.
+
 Stateless Authentication
 ~~~~~~~~~~~~~~~~~~~~~~~~
 

src/Silex/Provider/SecurityServiceProvider.php

@@ -12,6 +12,7 @@
 namespace Silex\Provider;
 
 use Pimple\Container;
+use Pimple\ServiceIterator;
 use Pimple\ServiceProviderInterface;
 use Silex\Application;
 use Silex\Api\BootableProviderInterface;
@@ -140,14 +141,29 @@ class SecurityServiceProvider implements ServiceProviderInterface, EventListener
         };
 
         $app['security.access_manager'] = function ($app) {
-            return new AccessDecisionManager($app['security.voters']);
+            $votersIterator = new ServiceIterator($app, $app['security.voter_services']);
+
+            return new AccessDecisionManager($votersIterator);
+        };
+
+        $app['security.voter_services'] = function () {
+            return [RoleHierarchyVoter::class, AuthenticatedVoter::class];
+        };
+
+        $app[RoleHierarchyVoter::class] = function ($app) {
+            return new RoleHierarchyVoter(new RoleHierarchy($app['security.role_hierarchy']));
+        };
+
+        $app[AuthenticatedVoter::class] = function ($app) {
+            return new AuthenticatedVoter($app['security.trust_resolver']);
         };
 
+        // Unused, kept for backwards-compatibility
+        // Extend security.voter_services instead to prevent circular references
         $app['security.voters'] = function ($app) {
-            return [
-                new RoleHierarchyVoter(new RoleHierarchy($app['security.role_hierarchy'])),
-                new AuthenticatedVoter($app['security.trust_resolver']),
-            ];
+            return array_map(function ($voterServiceId) use ($app) {
+                return $app[$voterServiceId];
+            });
         };
 
         $app['security.firewall'] = function ($app) {