Created utils for websockets.

client/src/main/java/client/MyModule.java

@@ -19,6 +19,8 @@ import client.scenes.FoodpalApplicationCtrl;
 import client.scenes.recipe.IngredientListCtrl;
 import client.scenes.recipe.RecipeStepListCtrl;
 import client.utils.LocaleManager;
+import client.utils.ServerUtils;
+import client.utils.WebSocketUtils;
 import com.google.inject.Binder;
 import com.google.inject.Module;
 import com.google.inject.Scopes;
@@ -33,6 +35,9 @@ public class MyModule implements Module {
         binder.bind(FoodpalApplicationCtrl.class).in(Scopes.SINGLETON);
         binder.bind(IngredientListCtrl.class).in(Scopes.SINGLETON);
         binder.bind(RecipeStepListCtrl.class).in(Scopes.SINGLETON);
+
         binder.bind(LocaleManager.class).in(Scopes.SINGLETON);
+        binder.bind(ServerUtils.class).in(Scopes.SINGLETON);
+        binder.bind(WebSocketUtils.class).in(Scopes.SINGLETON);
     }
 }

client/src/main/java/client/utils/WebSocketUtils.java

@@ -0,0 +1,111 @@
+package client.utils;
+
+import commons.ws.messages.Message;
+import org.springframework.messaging.converter.MappingJackson2MessageConverter;
+import org.springframework.messaging.simp.stomp.StompSession;
+import org.springframework.messaging.simp.stomp.StompHeaders;
+import org.springframework.messaging.simp.stomp.StompCommand;
+import org.springframework.messaging.simp.stomp.StompFrameHandler;
+import org.springframework.messaging.simp.stomp.StompSessionHandlerAdapter;
+import org.springframework.web.socket.client.standard.StandardWebSocketClient;
+import org.springframework.web.socket.messaging.WebSocketStompClient;
+
+import java.lang.reflect.Type;
+import java.util.function.Consumer;
+import javax.annotation.Nullable;
+import java.util.concurrent.CompletableFuture;
+
+public class WebSocketUtils {
+    private static final String WS_URL = "ws://localhost:8080/updates";
+    private WebSocketStompClient stompClient;
+    private StompSession stompSession;
+
+    /**
+     * Connect to the websocket server.
+     * @param onConnected OnConnected callback
+     */
+    public void connect(@Nullable Runnable onConnected) {
+        StandardWebSocketClient webSocketClient = new StandardWebSocketClient(); // Create WS Client
+
+        stompClient = new WebSocketStompClient(webSocketClient);
+        stompClient.setMessageConverter(new MappingJackson2MessageConverter()); // Use jackson
+
+        CompletableFuture<StompSession> sessionFuture = stompClient.connectAsync(
+                WS_URL,
+                new StompSessionHandlerAdapter() {
+                    @Override
+                    public void afterConnected(StompSession session, StompHeaders connectedHeaders) {
+                        stompSession = session;
+                        System.out.println("WebSocket connected: " + session.getSessionId());
+                    }
+
+                    @Override
+                    public void handleException(StompSession session, @Nullable StompCommand command,
+                                                StompHeaders headers, byte[] payload,
+                                                Throwable exception) {
+                        System.err.println("STOMP error: " + exception.getMessage());
+                        exception.printStackTrace();
+                    }
+
+                    @Override
+                    public void handleTransportError(StompSession session, Throwable exception) {
+                        System.err.println("STOMP transport error: " + exception.getMessage());
+                        exception.printStackTrace();
+                    }
+                }
+        );
+
+        sessionFuture.thenAccept(session -> {
+            stompSession = session;
+            System.out.println("Connection successful, session ready");
+            if (onConnected != null) {
+                onConnected.run();
+            }
+        }).exceptionally(throwable -> {
+            System.err.println("Failed to connect: " + throwable.getMessage());
+            throwable.printStackTrace();
+            return null;
+        });
+    }
+
+    /**
+     * Subscribe to a topic.
+     * @param destination Destination to subscribe to, for example: /subscribe/recipe
+     * @param messageHandler Handler for received messages
+     */
+    public void subscribe(String destination, Consumer<Message> messageHandler) {
+        if (stompSession == null || !stompSession.isConnected()) {
+            System.err.println("Cannot subscribe - not connected");
+            return;
+        }
+
+        stompSession.subscribe(destination, new StompFrameHandler() {
+            @Override
+            public Type getPayloadType(StompHeaders headers) {
+                return Message.class;
+            }
+
+            @Override
+            public void handleFrame(StompHeaders headers, @Nullable Object payload) {
+                Message message = (Message) payload;
+                messageHandler.accept(message);
+            }
+        });
+        System.out.println("Subscribed to: " + destination);
+    }
+
+    public void disconnect() {
+        if (stompSession != null && stompSession.isConnected()) {
+            stompSession.disconnect();
+        }
+
+        if (stompClient != null) {
+            stompClient.stop();
+        }
+    }
+
+    public boolean isConnected() {
+        return stompSession != null && stompSession.isConnected();
+    }
+
+}