add heartbeat to fix connection closing when idle

user.go

@@ -223,6 +223,9 @@ func userHandler(sock *websocket.Conn) {
 			// Release the user's display pointer
 			user.displayMtx.Unlock();
 
+		case "hb":
+			// Nothing to do, just a heart beat...
+
 		default:
 			// Give up
 			break;

www/scripts/user.js

@@ -74,6 +74,13 @@ class WisCastUserAPIClient {
                 dispID: dispID,
                 otp: OTP
             }))
+
+            // Send a heart-beat message every 30 seconds
+            setInterval(async () => {
+                await this.#sock.send(JSON.stringify({
+                    type: 'hb',
+                }))
+            }, 30000);
         });
     }