fixes for internal mxisd endpoints

internal/directory_lookup.php

@@ -8,8 +8,11 @@ $response=[
 try {
     $inputJSON = file_get_contents('php://input');
     $input = json_decode($inputJSON, TRUE);
+    if (empty($input)) {
+	    throw new Exception('no valid json as input present');
+    }
     if (!isset($input["by"])) {
-        throw new Exception('"id" is not defined');
+        throw new Exception('"by" is not defined');
     }
     if (!isset($input["search_term"])) {
         throw new Exception('"search_term" is not defined');
@@ -30,4 +33,4 @@ try {
     $response["error"] = $e->getMessage();
 }
 print (json_encode($response, JSON_PRETTY_PRINT) . "\n");
-?>
+?>