Merge 79895d455a into 8a432ac937

Some DNS servers might reply with several IP addresses. This avoids errors like the following:

```
Failing: UPDATE `monitor` SET dns_last_result = 'Records: X' WHERE id = 1  - Data too long for column 'dns_last_result' at row 1
```

db/knex_init_db.js

@@ -86,7 +86,7 @@ async function createTables() {
         table.text("accepted_statuscodes_json").notNullable().defaultTo("[\"200-299\"]");
         table.string("dns_resolve_type", 5);
         table.string("dns_resolve_server", 255);
-        table.string("dns_last_result", 255);
+        table.string("dns_last_result", 2000);
         table.integer("retry_interval").notNullable().defaultTo(0);
         table.string("push_token", 20).defaultTo(null);
         table.text("method").notNullable().defaultTo("GET");

server/socket-handlers/status-page-socket-handler.js

@@ -220,6 +220,9 @@ module.exports.statusPageSocketHandler = (socket) => {
 
             // Delete groups that are not in the list
             log.debug("socket", "Delete groups that are not in the list");
+            if (groupIDList.length === 0) {
+                await R.exec("DELETE FROM `group` WHERE status_page_id = ?", [ statusPage.id ]);
+            } else {
                 const slots = groupIDList.map(() => "?").join(",");
 
                 const data = [
@@ -227,6 +230,7 @@ module.exports.statusPageSocketHandler = (socket) => {
                     statusPage.id
                 ];
                 await R.exec(`DELETE FROM \`group\` WHERE id NOT IN (${slots}) AND status_page_id = ?`, data);
+            }
 
             const server = UptimeKumaServer.getInstance();