Connection Lifecycle Events

The extension fires CDI events when WebSocket clients connect and disconnect. Observe these events to log connections, initialize per-session state, or clean up resources on disconnect.

Observing Connections

import io.quarkiverse.jsonrpc.api.JsonRPCConnected;
import io.quarkiverse.jsonrpc.api.JsonRPCDisconnected;
import jakarta.enterprise.context.ApplicationScoped;
import jakarta.enterprise.event.Observes;

@ApplicationScoped
public class ConnectionObserver {

    void onConnect(@Observes JsonRPCConnected event) {
        Log.infof("Client connected: %s", event.sessionId());
    }

    void onDisconnect(@Observes JsonRPCDisconnected event) {
        Log.infof("Client disconnected: %s", event.sessionId());
    }
}

Both events carry a sessionId() — the same identifier used by JsonRPCBroadcaster to target individual clients.

Event Timing

JsonRPCConnected: Fires after session registration and identity setup but before message handlers are attached. The socket cannot yet receive JSON-RPC messages during observer execution.
JsonRPCDisconnected: Fires after the session has been fully cleaned up — session removed, identity cleared, subscriptions cancelled. Observers cannot send messages to the disconnecting client.

Threading

Both events fire on the Vert.x event loop thread. Observers must not perform blocking operations (database calls, HTTP requests, file I/O). If you need to do blocking work in response to a connection event, offload it:

@ApplicationScoped
public class ConnectionObserver {

    @Inject
    Vertx vertx;

    void onConnect(@Observes JsonRPCConnected event) {
        vertx.executeBlocking(() -> {
            // blocking work here
            return null;
        });
    }
}

Use with Broadcasting

Combine lifecycle events with JsonRPCBroadcaster to notify existing clients when someone joins:

@ApplicationScoped
public class PresenceObserver {

    @Inject
    JsonRPCBroadcaster broadcaster;

    void onConnect(@Observes JsonRPCConnected event) {
        broadcaster.broadcast("userJoined", Map.of("sessionId", event.sessionId()));
    }

    void onDisconnect(@Observes JsonRPCDisconnected event) {
        broadcaster.broadcast("userLeft", Map.of("sessionId", event.sessionId()));
    }
}