🌐 Websockets

In this section, we illustrate how to create and manage Websockets in Flash, which are used to establish a bidirectional communication channel between the client and the server.

Understanding Websockets

Websockets are a communication protocol that provides full-duplex communication channels over a single TCP connection. Unlike HTTP, which is a request-response protocol, Websockets allow for real-time, low-latency communication between the client and the server.

Imagine a scenario where you need to send real-time updates to the client, such as a chat application or a live feed: if you were to use HTTP, you would need to poll the server at regular intervals to check for updates, which is inefficient and resource-intensive.

Creating a Websocket

To create a Websocket in Flash, you need to extend the WebsocketHandler class and override the onOpen, onMessage, onClose, and onError methods.

public class MyWebsocketHandler extends WebsocketHandler {
    @Override
    public void onOpen(WebSocketSession session) {
        System.out.println("WebSocket connection opened");
    }

    @Override
    public void onClose(WebSocketSession session, int statusCode, String reason) {
        System.out.println("WebSocket connection closed");
    }

    @Override
    public void onMessage(WebSocketSession session, String message) {
        System.out.println("Received message: " + message);
        session.sendMessage("I received your message!");
    }

    @Override
    public void onError(WebSocketSession session, Throwable error) {
        System.out.println("WebSocket error: " + error.getMessage());
    }
}

To register your Websocket handler with the server, you can use the server.ws() method:

public class Example {
    public static void main(String[] args) {
        FlashServer server = new FlashServer(8080);

        server.ws("/ws")
            .register(MyWebsocketHandler.class);

        server.start();
    }
}

Interacting with Websockets sessions

The WebSocketSession object provides methods to interact with the Websocket session, such as sending messages, closing the connection, and getting the remote address and session ID.