PIX-41 Automatically unload empty lobbies from server memory and clean up client state on view unmount.

Author: matteosusca

server/src/services/canvas.service.ts

@@ -90,4 +90,23 @@ export class CanvasService {
 
     console.log(`[CanvasService] Saved lobby '${lobbyName}' to DB`);
   }
+
+  // Unloads a lobby from memory, persisting it first
+  static async unloadLobby(lobbyName: string) {
+    if (!canvasStore.isLobbyInMemory(lobbyName)) return;
+
+    console.log(`[CanvasService] Unloading idle lobby: ${lobbyName}`);
+
+    // If there's a pending save timer, cancel it and save immediately
+    if (this.saveTimers.has(lobbyName)) {
+      clearTimeout(this.saveTimers.get(lobbyName));
+      this.saveTimers.delete(lobbyName);
+    }
+
+    // Force strict save
+    await this.saveToDB(lobbyName);
+
+    // Remove from memory
+    canvasStore.removeLobby(lobbyName);
+  }
 }

server/src/sockets/index.ts

@@ -111,11 +111,20 @@ export const setupSocket = (io: Server) => {
 
 
     // --- DISCONNECTING ---
-    socket.on('disconnecting', () => {
+    socket.on('disconnecting', async () => {
       // Notify rooms that user is leaving
       for (const room of socket.rooms) {
         if (room !== socket.id) {
           socket.to(room).emit(CONFIG.EVENTS.SERVER.USER_LEFT, (socket as AuthenticatedSocket).user);
+
+          // Check if room is empty (excluding this socket)
+          const socketsInRoom = await io.in(room).fetchSockets();
+          const remainingUsers = socketsInRoom.length - 1; // fetchSockets includes the disconnecting socket
+
+          if (remainingUsers <= 0) {
+            // Room is empty, unload from hot storage
+            await CanvasService.unloadLobby(room);
+          }
         }
       }
     });

server/src/store/canvas.store.ts

@@ -48,6 +48,11 @@ export class CanvasStore {
   public getInMemoryLobbyIds(): string[] {
     return Array.from(this.lobbies.keys());
   }
+
+  public removeLobby(lobbyName: string): boolean {
+    console.log(`[CanvasStore] Removing lobby from memory: ${lobbyName}`);
+    return this.lobbies.delete(lobbyName);
+  }
 }
 
 export const canvasStore = new CanvasStore();