+ if ( self::$reqId ) {
+ return self::$reqId;
+ }
+
+ global $wgAllowExternalReqID;
+
+ self::$reqId = $_SERVER['UNIQUE_ID'] ?? wfRandomString( 24 );
+ if ( $wgAllowExternalReqID ) {
+ $id = RequestContext::getMain()->getRequest()->getHeader( 'X-Request-Id' );
+ if ( $id ) {
+ self::$reqId = $id;
+ }