--- a/plugins/FeedsProcessor.inc	2012-10-12 07:16:10.000000000 +0530
+++ b/plugins/FeedsProcessor.inc	2015-06-02 15:34:55.604801437 +0530
@@ -578,30 +578,43 @@
    * @return
    *   The serial id of an entity if found, 0 otherwise.
    */
-  protected function existingEntityId(FeedsSource $source, FeedsParserResult $result) {
+  protected function existingEntityId(FeedsSource $source, FeedsParserResult $result) {	  
     $query = db_select('feeds_item')
       ->fields('feeds_item', array('entity_id'))
       ->condition('feed_nid', $source->feed_nid)
       ->condition('entity_type', $this->entityType())
       ->condition('id', $source->id);
 
-    // Iterate through all unique targets and test whether they do already
-    // exist in the database.
+        // Iterate through all unique targets and test whether they do already
+		// exist in the database.
+		$targets = &drupal_static('FeedsProcessor::existingEntityId', array());
+		if (!isset($targets[$this->id])) {
+		  $targets[$this->id] = $this->getMappingTargets();
+	   }
+
+      $entity_id = 0;
+
+    
     foreach ($this->uniqueTargets($source, $result) as $target => $value) {
-      switch ($target) {
-        case 'url':
-          $entity_id = $query->condition('url', $value)->execute()->fetchField();
-          break;
-        case 'guid':
-          $entity_id = $query->condition('guid', $value)->execute()->fetchField();
-          break;
-      }
-      if (isset($entity_id)) {
-        // Return with the content id found.
-        return $entity_id;
+      if ($target === 'guid' || $target === 'url') {
+        $entity_id = $query->condition($target, $value)->execute()->fetchField();
+       }
+             if (!$entity_id && !empty($targets[$this->id][$target]['unique_callbacks'])) {
+       if (!is_array($value)) {
+          $value = array($value);
+       }		
+        foreach ($targets[$this->id][$target]['unique_callbacks'] as $callback) {
+          if (is_callable($callback) && $entity_id = call_user_func_array($callback, array($source, $this->entityType(), $this->config['content_type'], $target, $value))) {
+            // Stop at the first unique ID returned by a callback.
+            break;
+          }
+        }
       }
+      if($entity_id) {
+         return $entity_id;
+       }
     }
-    return 0;
+    return $entity_id;
   }