I did a simple web socket communication with spring 4,STOMP and sock.js, following this https://github.com/rstoyanchev/spring-websocket-portfolio and this http://assets.spring.io/wp/WebSocketBlogPost.html
well, I want to know if is possible capture connection events like when a new client was connected to my server or when a client was disconnected, is that possible in Spring 4.0.0?
This an be done with a connection handshake interceptor (HttpSessionHandshakeInterceptor), quoting the documentation:
The easiest way to customize the initial HTTP WebSocket handshake request is through a HandshakeInterceptor, which exposes "before" and "after" the handshake methods.
Spring WebSocket publishes events when messages are received from the client, if you are using STOMP, these are the events published:
The easiest way to detect connects and disconnects is by implementing an event listener for the mentioned events.
public class WebSocketEventListener {
@EventListener
private void handleSessionConnected(SessionConnectEvent event) {
...
}
@EventListener
private void handleSessionDisconnect(SessionDisconnectEvent event) {
...
}
}
Here's a sample implementation that keeps track of connected users: https://github.com/salmar/spring-websocket-chat/blob/master/src/main/java/com/sergialmar/wschat/event/PresenceEventListener.java
As I understand, the question with DISCONNECT event is not solved in this topic. Handshake interception gives you only connect info but not disconnect.
I have achieved this with the interceptors of inbound channel:
<websocket:message-broker>
...
<websocket:client-inbound-channel>
<websocket:interceptors>
<bean class="com......MyChannelInterception"></bean>
</websocket:interceptors>
</websocket:client-inbound-channel>
</websocket:message-broker>
...and class...
import java.security.Principal;
import org.apache.log4j.LogManager;
import org.apache.log4j.Logger;
import org.springframework.messaging.Message;
import org.springframework.messaging.MessageChannel;
import org.springframework.messaging.MessageHeaders;
import org.springframework.messaging.simp.SimpMessageType;
import org.springframework.messaging.support.ChannelInterceptorAdapter;
public class MyChannelInterception extends ChannelInterceptorAdapter {
private static final Logger LOGGER = LogManager.getLogger(WrcChannelInterception.class);
@Override
public Message<?> preSend(Message<?> message, MessageChannel channel) {
MessageHeaders headers = message.getHeaders();
SimpMessageType type = (SimpMessageType) headers.get("simpMessageType");
String simpSessionId = (String) headers.get("simpSessionId");
if (type == SimpMessageType.CONNECT) {
Principal principal = (Principal) headers.get("simpUser");
LOGGER.debug("WsSession " + simpSessionId + " is connected for user " + principal.getName());
} else if (type == SimpMessageType.DISCONNECT) {
LOGGER.debug("WsSession " + simpSessionId + " is disconnected");
}
return message;
}
}
Please note that Principal is available on CONNECT but not on DISCONNECT, however you have sweet Session ID
