Allows resolve event listeners to override or manipulate the resolved result

Author: iainmckay

Event/ResolveEvent.php

@@ -14,18 +14,23 @@ class ResolveEvent extends GenericEvent
 
     /** @var array */
     private $astFields;
+    
+    /** @var mixed|null */
+    private $resolvedValue;
 
     /**
      * Constructor.
      *
      * @param FieldInterface $field
      * @param array $astFields
+     * @param mixed|null $resolvedValue
      */
-    public function __construct(FieldInterface $field, array $astFields)
+    public function __construct(FieldInterface $field, array $astFields, $resolvedValue = null)
     {
         $this->field = $field;
         $this->astFields = $astFields;
-        parent::__construct('ResolveEvent', [$field, $astFields]);
+        $this->resolvedValue = $resolvedValue;
+        parent::__construct('ResolveEvent', [$field, $astFields, $resolvedValue]);
     }
 
     /**
@@ -47,4 +52,25 @@ public function getAstFields()
     {
         return $this->astFields;
     }
+
+    /**
+     * Returns the resolved value.
+     * 
+     * @return mixed|null
+     */
+    public function getResolvedValue()
+    {
+        return $this->resolvedValue;
+    }
+
+    /**
+     * Allows the event listener to manipulate the resolved value.
+     * 
+     * @param $resolvedValue
+     */
+    public function setResolvedValue($resolvedValue)
+    {
+        $this->resolvedValue = $resolvedValue;
+    }
 }
+

Execution/Processor.php

@@ -116,9 +116,9 @@ protected function doResolve(FieldInterface $field, AstFieldInterface $ast, $par
             $result = $field->resolve($parentValue, $arguments, $resolveInfo);
         }
 
-        $event = new ResolveEvent($field, $astFields);
+        $event = new ResolveEvent($field, $astFields, $result);
         $this->eventDispatcher->dispatch('graphql.post_resolve', $event);
-        return $result;
+        return $event->getResolvedValue();
     }
 
     private function assertClientHasOperationAccess(Query $query)