diff --git a/classes/external/trigger_dataflow.php b/classes/external/trigger_dataflow.php
index 58a0575d..432453ab 100644
--- a/classes/external/trigger_dataflow.php
+++ b/classes/external/trigger_dataflow.php
@@ -16,6 +16,10 @@
 
 namespace tool_dataflows\external;
 
+defined('MOODLE_INTERNAL') || die();
+
+require_once($CFG->libdir . '/externallib.php');
+
 use external_function_parameters;
 use external_single_structure;
 use external_value;