[Rspamd] Use last-modified headers to not read unmodified settings map every 30 seconds

data/conf/rspamd/dynmaps/settings.php

@@ -7,8 +7,6 @@ then any of these will trigger the rule. If a rule is triggered then no more rul
 header('Content-Type: text/plain');
 require_once "vars.inc.php";
 // Getting headers sent by the client.
-//$headers = apache_request_headers();
-
 ini_set('error_reporting', 0);
 
 //$dsn = $database_type . ':host=' . $database_host . ';dbname=' . $database_name;
@@ -28,21 +26,22 @@ catch (PDOException $e) {
 }
 
 // Check if db changed and return header
-/*$stmt = $pdo->prepare("SELECT UNIX_TIMESTAMP(UPDATE_TIME) AS `db_update_time` FROM information_schema.tables
+$stmt = $pdo->prepare("SELECT UNIX_TIMESTAMP(UPDATE_TIME) AS `db_update_time` FROM information_schema.tables
   WHERE `TABLE_NAME` = 'filterconf'
     AND TABLE_SCHEMA = :dbname;");
 $stmt->execute(array(
   ':dbname' => $database_name
 ));
 $db_update_time = $stmt->fetch(PDO::FETCH_ASSOC)['db_update_time'];
-
-if (isset($headers['If-Modified-Since']) && (strtotime($headers['If-Modified-Since']) == $db_update_time)) {
+if (empty($db_update_time)) {
+  $db_update_time = 1572048000;
+}
+if (isset($_SERVER['HTTP_IF_MODIFIED_SINCE']) && (strtotime($_SERVER['HTTP_IF_MODIFIED_SINCE']) == $db_update_time)) {
   header('Last-Modified: '.gmdate('D, d M Y H:i:s', $db_update_time).' GMT', true, 304);
   exit;
 } else {
   header('Last-Modified: '.gmdate('D, d M Y H:i:s', $db_update_time).' GMT', true, 200);
 }
-*/
 
 function parse_email($email) {
   if (!filter_var($email, FILTER_VALIDATE_EMAIL)) return false;