added method to parse post data

application/core/APIv1_Controller.php

@@ -4,10 +4,42 @@ require_once APPPATH . '/libraries/REST_Controller.php';
 
 class APIv1_Controller extends REST_Controller 
 {
-	function __construct()  
-	{
-        parent::__construct();
-		//$this->load->library('session'); // -> autoload
-		//$this->load->library('database'); -> autoload
+    function __construct()  
+    {
+    parent::__construct();
+            //$this->load->library('session'); // -> autoload
+            //$this->load->library('database'); -> autoload
+    
+    }
+    
+    /**
+     * 
+     * @param type $data
+     * @return typeparses empty string to NULL
+     */
+    protected function _parseData($data)
+    {
+        if(is_array($data))
+        {
+            foreach($data as $key=>$value)
+            {
+                if($value === "")
+                {
+                    $data[$key] = NULL;
+                }
+            }
+            return $data;
+        }
+        elseif(is_object($data))
+        {
+            //TODO
+        }
+        else
+        {
+            if($data == "")
+            {
+                return NULL;
+            }
+        }
     }
 }