only allow for valid urls in slack button (#5312)

server/notification-providers/slack.js

@@ -1,7 +1,7 @@
 const NotificationProvider = require("./notification-provider");
 const axios = require("axios");
 const { setSettings, setting } = require("../util-server");
-const { getMonitorRelativeURL, UP } = require("../../src/util");
+const { getMonitorRelativeURL, UP, log } = require("../../src/util");
 
 class Slack extends NotificationProvider {
     name = "slack";
@@ -50,6 +50,7 @@ class Slack extends NotificationProvider {
 
         const address = this.extractAddress(monitorJSON);
         if (address) {
+            try {
                 actions.push({
                     "type": "button",
                     "text": {
@@ -57,8 +58,12 @@ class Slack extends NotificationProvider {
                         "text": "Visit site",
                     },
                     "value": "Site",
-                "url": address,
+                    "url": new URL(address),
                 });
+
+            } catch (e) {
+                log.debug("slack", `Failed to parse address ${address} as URL`);
+            }
         }
 
         return actions;