add abstract voter implementation, reducing boilerplate required for …

…custom voter
symfony · inoryy · Jun 20, 2014 · Aug 23, 2014 · Aug 23, 2014 · Sep 23, 2014
commit 4a7bfe2e786335b9546ace72e4396d3785b3da1b
diff --git a/src/Symfony/Component/Security/Core/Authorization/Voter/AbstractVoter.php b/src/Symfony/Component/Security/Core/Authorization/Voter/AbstractVoter.php
@@ -0,0 +1,93 @@
+<?php
+
+namespace Symfony\Component\Security\Core\Authorization\Voter;
+
+use Symfony\Component\Security\Core\User\UserInterface;
+use Symfony\Component\Security\Core\Authentication\Token\TokenInterface;
+
+/**
+ * Abstract Voter implementation that reduces boilerplate code required to create a custom Voter
+ *
+ * @author Roman Marintšenko <inoryy@gmail.com>
+ */
+abstract class AbstractVoter implements VoterInterface
+{
+    /**
+     * {@inheritdoc}
+     */
+    public function supportsAttribute($attribute)
+    {
+        return in_array($attribute, $this->getSupportedAttributes());
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function supportsClass($class)
+    {
+        foreach ($this->getSupportedClasses() as $supportedClass) {
+            if ($supportedClass === $class || is_subclass_of($class, $supportedClass)) {
+                return true;
+            }
+        }
+
+        return false;
+    }
+
+    /**
+     * Iteratively check all given attributes by calling voteOnAttribute
+     * This method terminates as soon as it is able to return either ACCESS_GRANTED or ACCESS_DENIED vote
+     * Otherwise it will return ACCESS_ABSTAIN
+     *
+     * @param TokenInterface $token      A TokenInterface instance
+     * @param object         $object     The object to secure
+     * @param array          $attributes An array of attributes associated with the method being invoked
+     *
+     * @return int     either ACCESS_GRANTED, ACCESS_ABSTAIN, or ACCESS_DENIED
+     */
+    public function vote(TokenInterface $token, $object, array $attributes)
+    {
+        if (!$this->supportsClass(get_class($object))) {
+            return VoterInterface::ACCESS_ABSTAIN;
+        }
+
+        $user = $token->getUser();
+
+        foreach ($attributes as $attribute) {
+            if ($this->supportsAttribute($attribute)) {
+                $vote = $this->voteOnAttribute($attribute, $object, $user);
+                if (VoterInterface::ACCESS_ABSTAIN !== $vote) {
+                    return $vote;
+                }
+            }
+        }
+
+        return VoterInterface::ACCESS_ABSTAIN;
+    }
+
+    /**
+     * Return an array of supported classes. This will be called by supportsClass
+     *
+     * @return array    an array of supported classes, i.e. ['\Acme\DemoBundle\Model\Product']
+     */
+    abstract protected function getSupportedClasses();
+
+    /**
+     * Return an array of supported attributes. This will be called by supportsAttribute
+     *
+     * @return array    an array of supported attributes, i.e. ['CREATE', 'READ']
+     */
+    abstract protected function getSupportedAttributes();
+
+    /**
+     * Perform a single vote operation on a given attribute, object and (optionally) user
+     * It is safe to assume that $attribute and $object's class pass supportsAttribute/supportsClass
+     *
+     * @param string        $attribute
+     * @param object        $object
+     * @param UserInterface $user
+     *
+     * @return int     either ACCESS_GRANTED, ACCESS_ABSTAIN, or ACCESS_DENIED
+     */
+    abstract protected function voteOnAttribute($attribute, $object, UserInterface $user = null);
+}