story-kit: merge 138_bug_no_heartbeat_to_detect_stale_websocket_connections

server/src/http/ws.rs

@@ -29,6 +29,9 @@ enum WsRequest {
         request_id: String,
         approved: bool,
     },
+    /// Heartbeat ping from the client. The server responds with `Pong` so the
+    /// client can detect stale (half-closed) connections.
+    Ping,
 }
 
 #[derive(Serialize)]
@@ -91,6 +94,9 @@ enum WsResponse {
         status: String,
         message: String,
     },
+    /// Heartbeat response to a client `Ping`. Lets the client confirm the
+    /// connection is alive and cancel any stale-connection timeout.
+    Pong,
 }
 
 impl From<WatcherEvent> for Option<WsResponse> {
@@ -285,6 +291,9 @@ pub async fn ws_handler(ws: WebSocket, ctx: Data<&Arc<AppContext>>) -> impl poem
                                     Ok(WsRequest::Cancel) => {
                                         let _ = chat::cancel_chat(&ctx.state);
                                     }
+                                    Ok(WsRequest::Ping) => {
+                                        let _ = tx.send(WsResponse::Pong);
+                                    }
                                     _ => {}
                                 }
                             }
@@ -305,6 +314,9 @@ pub async fn ws_handler(ws: WebSocket, ctx: Data<&Arc<AppContext>>) -> impl poem
                 Ok(WsRequest::Cancel) => {
                     let _ = chat::cancel_chat(&ctx.state);
                 }
+                Ok(WsRequest::Ping) => {
+                    let _ = tx.send(WsResponse::Pong);
+                }
                 Ok(WsRequest::PermissionResponse { .. }) => {
                     // Permission responses outside an active chat are ignored.
                 }
@@ -385,6 +397,13 @@ mod tests {
         assert!(matches!(req, WsRequest::Cancel));
     }
 
+    #[test]
+    fn deserialize_ping_request() {
+        let json = r#"{"type": "ping"}"#;
+        let req: WsRequest = serde_json::from_str(json).unwrap();
+        assert!(matches!(req, WsRequest::Ping));
+    }
+
     #[test]
     fn deserialize_permission_response_approved() {
         let json = r#"{
@@ -538,6 +557,13 @@ mod tests {
         assert_eq!(json["type"], "agent_config_changed");
     }
 
+    #[test]
+    fn serialize_pong_response() {
+        let resp = WsResponse::Pong;
+        let json = serde_json::to_value(&resp).unwrap();
+        assert_eq!(json["type"], "pong");
+    }
+
     #[test]
     fn serialize_permission_request_response() {
         let resp = WsResponse::PermissionRequest {