Add Expression Language

composer.json

@@ -18,6 +18,7 @@
         "php": ">= 8.1",
         "ext-json": "*",
         "symfony/console": "^5.4|^6.0|^7.0",
+        "symfony/expression-language": "^5.4|^6.0|^7.0",
         "symfony/framework-bundle": "^5.4|^6.0|^7.0",
         "symfony/options-resolver": "^5.4|^6.0|^7.0"
     },
@@ -26,7 +27,7 @@
         "symfony/asset": "^5.4|^6.0|^7.0",
         "symfony/browser-kit": "^5.4|^6.0|^7.0",
         "symfony/css-selector": "^5.4|^6.0|^7.0",
-        "symfony/expression-language": "^5.4|^6.0|^7.0",
+        "symfony/security-bundle": "^5.4|^6.0|^7.0",
         "symfony/templating": "^5.4|^6.0|^7.0",
         "symfony/twig-bundle": "^5.4|^6.0|^7.0",
         "symfony/yaml": "^5.4|^6.0|^7.0",

src/Checker/ExpressionLanguageChecker.php

@@ -0,0 +1,73 @@
+<?php
+
+declare(strict_types=1);
+
+/*
+ * This file is part of the NovawayFeatureFlagBundle package.
+ * (c) Novaway <https://github.com/novaway/NovawayFeatureFlagBundle>
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Novaway\Bundle\FeatureFlagBundle\Checker;
+
+use Psr\Log\LoggerInterface;
+use Symfony\Component\ExpressionLanguage\ExpressionLanguage;
+use Symfony\Component\Security\Core\Authentication\AuthenticationTrustResolverInterface;
+use Symfony\Component\Security\Core\Authentication\Token\NullToken;
+use Symfony\Component\Security\Core\Authentication\Token\Storage\TokenStorageInterface;
+use Symfony\Component\Security\Core\Authentication\Token\TokenInterface;
+use Symfony\Component\Security\Core\Authorization\AuthorizationCheckerInterface;
+use Symfony\Component\Security\Core\Role\RoleHierarchyInterface;
+
+class ExpressionLanguageChecker
+{
+    public function __construct(
+        private readonly ?ExpressionLanguage $expressionLanguage = null,
+        private readonly ?AuthenticationTrustResolverInterface $authenticationTrustResolver = null,
+        private readonly ?RoleHierarchyInterface $roleHierarchy = null,
+        private readonly ?TokenStorageInterface $tokenStorage = null,
+        private readonly ?AuthorizationCheckerInterface $authorizationChecker = null,
+        private readonly ?LoggerInterface $logger = null,
+    ) {
+    }
+
+    public function isGranted(string $expression): bool
+    {
+        if (
+            null === $this->expressionLanguage
+            || null === $this->tokenStorage
+            || null === $this->authenticationTrustResolver
+        ) {
+            throw new \LogicException('The "symfony/security-bundle" library must be installed.');
+        }
+
+        if (null === $token = $this->tokenStorage->getToken()) {
+            $token = new NullToken();
+        }
+
+        $variables = [
+            'trust_resolver' => $this->authenticationTrustResolver,
+            'auth_checker' => $this->authorizationChecker, // needed for the is_granted expression function
+            'token' => $token,
+            'user' => $token->getUser(),
+            'roles' => $this->getEffectiveRoles($token),
+        ];
+
+        $this->logger?->info(
+            'Evaluate expression Language',
+            ['expression' => $expression, 'variable' => $variables]
+        );
+
+        return (bool) $this->expressionLanguage->evaluate($expression, $variables);
+    }
+
+    private function getEffectiveRoles(TokenInterface $token): array
+    {
+        if (null === $this->roleHierarchy) {
+            return $token->getRoleNames();
+        }
+
+        return $this->roleHierarchy->getReachableRoleNames($token->getRoleNames());
+    }
+}

src/Command/ListFeatureCommand.php

@@ -41,10 +41,12 @@ protected function execute(InputInterface $input, OutputInterface $output): int
     {
         $storagesFeatures = [];
         foreach ($this->manager->getManagers() as $manager) {
-            $storagesFeatures[$manager->getName()] = [];
+            $features = [];
             foreach ($manager->all() as $feature) {
-                $storagesFeatures[$manager->getName()][$feature->getKey()] = $feature->toArray();
+                $features[$feature->getKey()] = $feature->toArray();
             }
+
+            $storagesFeatures[$manager->getName()] = $features;
         }
 
         try {

src/DependencyInjection/NovawayFeatureFlagExtension.php

@@ -58,6 +58,7 @@ public function load(array $configs, ContainerBuilder $container): void
                 ->register(sprintf('novaway_feature_flag.manager.%s', $name), DefaultFeatureManager::class)
                 ->addArgument($name)
                 ->addArgument(new Reference('novaway_feature_flag.storage.'.$name))
+                ->addArgument(new Reference('novaway_feature_flag.checker.expression_language'))
                 ->addTag('novaway_feature_flag.manager')
             ;
         }

src/Manager/DefaultFeatureManager.php

@@ -9,6 +9,7 @@
 
 namespace Novaway\Bundle\FeatureFlagBundle\Manager;
 
+use Novaway\Bundle\FeatureFlagBundle\Checker\ExpressionLanguageChecker;
 use Novaway\Bundle\FeatureFlagBundle\Model\Feature;
 use Novaway\Bundle\FeatureFlagBundle\Storage\FeatureUndefinedException;
 use Novaway\Bundle\FeatureFlagBundle\Storage\Storage;
@@ -18,6 +19,7 @@ class DefaultFeatureManager implements FeatureManager
     public function __construct(
         private readonly string $name,
         private readonly Storage $storage,
+        private readonly ExpressionLanguageChecker $expressionLanguageChecker,
     ) {
     }
 
@@ -37,7 +39,17 @@ public function all(): iterable
     public function isEnabled(string $feature): bool
     {
         try {
-            return $this->storage->get($feature)->isEnabled();
+            $featureObject = $this->storage->get($feature);
+
+            if ($featureObject->isEnabled()) {
+                if (!empty($featureObject->getExpression())) {
+                    return $this->expressionLanguageChecker->isGranted($featureObject->getExpression());
+                }
+
+                return true;
+            }
+
+            return false;
         } catch (FeatureUndefinedException) {
             return false;
         }

src/Model/Feature.php

@@ -26,6 +26,8 @@ public function getDescription(): string;
      */
     public function isEnabled(): bool;
 
+    public function getExpression(): ?string;
+
     /**
      * @return array{key: string, enabled: bool, description: string}
      */

src/Model/FeatureFlag.php

@@ -17,6 +17,7 @@ final class FeatureFlag implements Feature
     public function __construct(
         private readonly string $key,
         private readonly bool $enabled,
+        private readonly ?string $expression = null,
         private readonly string $description = ''
     ) {
     }
@@ -36,11 +37,17 @@ public function isEnabled(): bool
         return $this->enabled;
     }
 
+    public function getExpression(): ?string
+    {
+        return $this->expression;
+    }
+
     public function toArray(): array
     {
         return [
             'key' => $this->key,
             'enabled' => $this->enabled,
+            'expression' => $this->expression,
             'description' => $this->description,
         ];
     }

src/Resources/config/services.php

@@ -9,6 +9,7 @@
  * file that was distributed with this source code.
  */
 
+use Novaway\Bundle\FeatureFlagBundle\Checker\ExpressionLanguageChecker;
 use Novaway\Bundle\FeatureFlagBundle\EventListener\ControllerListener;
 use Novaway\Bundle\FeatureFlagBundle\EventListener\FeatureListener;
 use Novaway\Bundle\FeatureFlagBundle\Factory\ArrayStorageFactory;
@@ -17,6 +18,7 @@
 use Novaway\Bundle\FeatureFlagBundle\Manager\FeatureManager;
 use Symfony\Component\DependencyInjection\Loader\Configurator\ContainerConfigurator;
 
+use function Symfony\Component\DependencyInjection\Loader\Configurator\service;
 use function Symfony\Component\DependencyInjection\Loader\Configurator\tagged_iterator;
 
 return static function (ContainerConfigurator $containerConfigurator): void {
@@ -26,6 +28,17 @@
 
     $services->set('novaway_feature_flag.factory.array', ArrayStorageFactory::class);
 
+    $services->set('novaway_feature_flag.checker.expression_language', ExpressionLanguageChecker::class)
+        ->args([
+            service('security.expression_language')->nullOnInvalid(),
+            service('security.authentication.trust_resolver')->nullOnInvalid(),
+            service('security.role_hierarchy')->nullOnInvalid(),
+            service('security.token_storage')->nullOnInvalid(),
+            service('security.authorization_checker')->nullOnInvalid(),
+            service('logger')->nullOnInvalid(),
+        ])
+    ;
+
     $services->set(ChainedFeatureManager::class)
         ->args([tagged_iterator('novaway_feature_flag.manager')]);
 

src/Storage/ArrayStorage.php

@@ -19,7 +19,12 @@ class ArrayStorage implements Storage
     public function __construct(array $options = [])
     {
         $this->features = array_map(function (array $feature) {
-            return new FeatureFlag($feature['name'], $feature['enabled'], $feature['description'] ?? '');
+            return new FeatureFlag(
+                key: $feature['name'],
+                enabled: $feature['enabled'],
+                expression: $feature['expression'] ?? null,
+                description: $feature['description'] ?? ''
+            );
         }, $options['features']);
     }