applying PR ongr-io#358

Author: Lindsay Snider

Diff for: src/Search.php

@@ -67,6 +67,13 @@ class Search
      */
     private $source;
 
+    /**
+     * Allows to selectively load specific source fields for each document represented by a search hit.
+     *
+     * @var array
+     */
+    private $sourceFields;
+
     /**
      * Allows to selectively load specific stored fields for each document represented by a search hit.
      *
@@ -537,6 +544,26 @@ public function setSource($source)
         return $this;
     }
 
+    /**
+     * @return array
+     */
+    public function getSourceFields()
+    {
+        return $this->sourceFields;
+    }
+
+    /**
+     * @param array $sourceFields
+     *
+     * @return $this
+     */
+    public function setSourceFields($sourceFields)
+    {
+        $this->sourceFields = $sourceFields;
+
+        return $this;
+    }
+
     /**
      * @return array
      */
@@ -793,6 +820,12 @@ public function toArray()
             'trackTotalHits' => 'track_total_hits',
         ];
 
+        if(!empty($this->sourceFields))
+        {
+            unset($params['source']);
+            $params['sourceFields'] = '_source';
+        }
+
         foreach ($params as $field => $param) {
             if ($this->$field !== null) {
                 $output[$param] = $this->$field;