abstractgetattributesubscribe; re-allowing to update values of existing user attributes

src/Authorization/AuthorizationDataMuxer.php

@@ -112,7 +112,6 @@ class AuthorizationDataMuxer
             throw new AuthorizationException(sprintf('attribute \'%s\' undefined', $attributeName), AuthorizationException::ATTRIBUTE_UNDEFINED);
         }
 
-        $wasFound = false;
         $value = $defaultValue;
         foreach ($this->authorizationDataProviders as $authorizationDataProvider) {
             $availableAttributes = $this->getProviderAvailableAttributes($authorizationDataProvider);
@@ -130,7 +129,7 @@ class AuthorizationDataMuxer
         $event = new GetAttributeEvent($this, $attributeName, $value, $userIdentifier);
         $event->setAttributeValue($value);
 
-        // Avoid endless recursions by only emitting an event for each attribtue only once
+        // Avoid endless recursions by only emitting an event for each attribute only once
         if (!in_array($attributeName, $this->attributeStack, true)) {
             array_push($this->attributeStack, $attributeName);
             $this->eventDispatcher->dispatch($event);

src/Authorization/EventSubscriber/AbstractGetAttributeSubscriber.php

@@ -23,18 +23,19 @@ abstract class AbstractGetAttributeSubscriber implements EventSubscriberInterfac
 
     public function onGetAvailableAttributes(GetAvailableAttributesEvent $event)
     {
-        $event->addAttributes($this->getAvailableAttributes());
+        $event->addAttributes($this->getNewAttributes());
     }
 
     public function onGetAttributeEvent(GetAttributeEvent $event)
     {
         try {
             $this->event = $event;
-
             $attributeName = $event->getAttributeName();
-            if (in_array($attributeName, $this->getAvailableAttributes(), true)) {
-                $event->setAttributeValue($this->getUserAttributeValue($event->getUserIdentifier(), $attributeName, $event->getAttributeValue()));
-            }
+
+            $event->setAttributeValue(in_array($attributeName, $this->getNewAttributes(), true) ?
+                $this->getNewAttributeValue($event->getUserIdentifier(), $attributeName, $event->getAttributeValue()) :
+                $this->updateExistingAttributeValue($event->getUserIdentifier(), $attributeName, $event->getAttributeValue())
+            );
         } finally {
             $this->event = null;
         }
@@ -50,15 +51,25 @@ abstract class AbstractGetAttributeSubscriber implements EventSubscriberInterfac
         return $this->event->getAttribute($attributeName, $defaultValue);
     }
 
+    /**
+     * @param mixed|null $attributeValue The current attribute value
+     *
+     * @return mixed|null The updated attribute value
+     */
+    protected function updateExistingAttributeValue(?string $userIdentifier, string $attributeName, $attributeValue)
+    {
+        return $attributeValue;
+    }
+
     /*
-     * @return string[]
+     * @return string[] The array of new attribute names that this subscriber provides
      */
-    abstract protected function getAvailableAttributes(): array;
+    abstract protected function getNewAttributes(): array;
 
     /**
-     * @param mixed|null $attributeValue
+     * @param mixed|null $defaultValue the default value if provided explicitly in the authorization expression, else null
      *
-     * @return mixed|null
+     * @return mixed|null the value for the new attribute with the given name for the given user
      */
-    abstract protected function getUserAttributeValue(?string $userIdentifier, string $attributeName, $attributeValue);
+    abstract protected function getNewAttributeValue(?string $userIdentifier, string $attributeName, $defaultValue);
 }

[Reiter, Christoph]

$defaultValue doesn't really work here, since we can only decide if it should be used after all events handlers are done, and this might not be the only one i.e. the event handler must never see the default value.