I have a requirement where my Websocket session should be able to communicate with each other.I am creating a Request Response model where my Client A would send a request on a Queue on which I have multiple subscriber agents (Ag1 and Ag2). I would expect that my requests would round robin between these 2 subscribers. Unfortunately, the event is broadcasted to both the agents rather than it being a one to one communication.
My Spring config
#Override
public void registerStompEndpoints(StompEndpointRegistry registry) {
registry.addEndpoint("/websocket").withSockJS();
}
#Override
public void configureMessageBroker(MessageBrokerRegistry config) {
config.setApplicationDestinationPrefixes("/app");
config.enableSimpleBroker("/queue", "/topic");
}
Client JS Code
requestResponse = new RequestResponse({
outgoingChannel : "/queue/clients",
incomingChannel : "/topic/broadcast/clients",
callbackFn : widget3eventHandler
},session);
Agent Subscriber Code
requestResponse = new RequestResponse({
outgoingChannel : "/topic/broadcast/clients",
incomingChannel : "/queue/clients",
callbackFn : widget3eventHandler,
processAll : true
},session);
Is this a bug in SIMP Broker or am i doing something wrong.
You can check this sample chat application if you want to know how to achieve client to client communication.
Related
My spring websocket configuration is as follows:
public void configureMessageBroker(MessageBrokerRegistry config) {
config.enableSimpleBroker("/topic");
config.setApplicationDestinationPrefixes("/app", "/watch");
config.setPreservePublishOrder(true);
}
public void registerStompEndpoints(StompEndpointRegistry registry) {
RequestUpgradeStrategy upgradeStrategy = new TomcatRequestUpgradeStrategy();
registry.addEndpoint("/ui/ws").setHandshakeHandler(new DefaultHandshakeHandler(upgradeStrategy))
.addInterceptors(handshakeInterceptor())
.setAllowedOriginPatterns("*").withSockJS().setHeartbeatTime(10000);
}
I have handlers for processing messages sent by the client.
But the handlers are called out of order.
I can see that the com.vrts.gms.ui.base.websocket.WebSocketChannelInterceptor receives the messages in order. But after that, it searches for a handler method and calls it asynchronously. The org.springframework.web.socket.messaging.WebSocketAnnotationMethodMessageHandler receives the messages in wrong order.
I have already set setPreservePublishOrder(true). I don't want to limit the threads.
Is there any support from spring for this?
I have two Java processes and I am connecting them using a websocket in spring boot. One process acts as the client and connects like this:
List<Transport> transports = new ArrayList<Transport>(1);
transports.add(new WebSocketTransport(new StandardWebSocketClient()));
WebSocketClient client = new SockJsClient(transports);
WebSocketStompClient stompClient = new WebSocketStompClient(client);
stompClient.setMessageConverter(new MappingJackson2MessageConverter());
StompSessionHandler firstSessionHandler = new MyStompSessionHandler("Philip");
stompClient.connect("ws://localhost:8080/chat", firstSessionHandler);
The session handler extends StompSessionHandlerAdapter and provides these methods (I am subscribing by username so each client can receive its own messages):
#Override
public void afterConnected(
StompSession session, StompHeaders connectedHeaders) {
session.subscribe("/user/" + userName + "/reply", this);
session.send("/app/chat", getSampleMessage());
}
#Override
public void handleFrame(StompHeaders headers, Object payload) {
Message msg = (Message) payload;
// etc.....
}
On the server side I have a Controller exposed and I am writing data by calling the endpoint from a worker thread.
#Autowired
private SimpMessagingTemplate template;
#MessageMapping("/chat")
public void send(
Message message)
throws Exception {
template.convertAndSendToUser(message.getFrom(),
"/reply",
message);
}
In the websocket config I am overriding the method to set the limits:
#Configuration
#EnableWebSocketMessageBroker
public class WebSocketConfig extends AbstractWebSocketMessageBrokerConfigurer {
#Override
public void configureMessageBroker(MessageBrokerRegistry config) {
config.enableSimpleBroker("/topic", "/user");
config.setApplicationDestinationPrefixes("/app");
}
#Override
public void configureWebSocketTransport(WebSocketTransportRegistration registration) {
registration.setMessageSizeLimit(500 * 1024);
registration.setSendBufferSizeLimit(1024 * 1024);
registration.setSendTimeLimit(20000);
}
My question is this, if the load on the server gets high enough and I overrun the limit, the websocket fails catastrophically, and I want to avoid this. What I would like to do is for the controller to have the ability to ask the message broker "will this message fit in the buffer?", so that I can throttle to stay under the limit. I searched the API documentation but I don't see any way of doing that. Are there any other obvious solutions that I am missing?
Thanks.
Actually I found a solution, so if anyone is interested, here it is.
On the server side configuration of the websockets I installed an Interceptor on the Outbound Channel (this is part of the API), which is called after each send from the embedded broker.
So I know how much is coming in, which I keep track of in my Controller class and I know how much is going out through the Interceptor that I installed, and this allows me to always stay under the limit.
The controller, before accepting any new messages to be queued up for the broker first determines if enough room is available and if not queues up the message in external storage until such time as room becomes available.
I am using spring boot as per examples for TcpInboundGateway,so different devices send data to this Gateways,things works fine but in between in logs it showing following exception:
2015-12-29 18:42:19.455 ERROR 3465 --- [ool-3-thread-47] o.s.i.i.tcp.connection.TcpNetConnection : Read exception 106.221.159.216:38170:8765:934c050d-c4b5-4466-98ab-ee87714c3d00 SocketException:Connection reset
If this exception is resetting connection then how to avoid this reset?What is the cause of this error?
My code as follows
#SpringBootApplication
#IntegrationComponentScan
public class SpringIntegrationApplication extends SpringBootServletInitializer{
public static void main(String[] args) throws IOException {
ConfigurableApplicationContext ctx = SpringApplication.run(SpringIntegrationApplication.class, args);
System.in.read();
ctx.close();
}
#Override
protected SpringApplicationBuilder configure(SpringApplicationBuilder application) {
return application.sources(SpringIntegrationApplication.class);
}
private static Class<SpringIntegrationApplication> applicationClass = SpringIntegrationApplication.class;
#Bean
TcpNetServerConnectionFactory cf(){
TcpNetServerConnectionFactory connectionFactory=new TcpNetServerConnectionFactory(8765);
return connectionFactory;
}
#Bean
TcpInboundGateway tcpGate(){
TcpInboundGateway gateway=new TcpInboundGateway();
gateway.setConnectionFactory(cf());
gateway.setRequestChannel(requestChannel());
return gateway;
}
#Bean
public MessageChannel requestChannel(){
return new DirectChannel();
}
#MessageEndpoint
public class Echo {
#ServiceActivator(inputChannel="requestChannel")
public byte[] echo(byte[] in,#SuppressWarnings("deprecation") #Header("ip_address") String ip){
byte[] rawbytes = gosDataSerivce.byteArrayToHex(in,ip);//Process bytes and returns result
return rawbytes;
}
}
}
After setting singleUse to true now exception message is changed slightly.
2015-12-31 06:09:00.481 ERROR 16450 --- [ool-3-thread-10] o.s.i.i.tcp.connection.TcpNetConnection : Read exception 106.221.146.40:9195:8765:1b4755e8-5b0c-44b9-b4e6-b3aacc25e228 SocketException:Connection reset
Use Case:
I have several clients that established GPRS connection to TcpInboundGateWay and sends login packet,our server will reply to this login packet.If client receives server reply to login packet then it will send data packets at regular interval. Server needs to reply to these packet also if server fails to send reply to those data packets then client GPRS connection is terminated and client will try to establish connections again.Let me know if this use case can be handle with TcpInboundGateWay
Network Trace Analysis
General flow of communication between client and server is as follows:Client sends login packet from ip say 106.221.148.165 so at server connection named 106.221.148.165:63430:8765:cc105da2-dae4-494b-af9c-d1ba268f34f1 is created, that client sends subsequent packets from that ip only.So everything works fine,but after some time same client sends its login packet from another ip say 106.221.142.204.And subsequent packets from new ip.But in logs following error comes that for previous connection exception occurred.
2016-01-05 05:16:14.871 ERROR 6819 --- [pool-3-thread-5] o.s.i.i.tcp.connection.TcpNetConnection : Read exception 106.221.148.165:63430:8765:cc105da2-dae4-494b-af9c-d1ba268f34f1 SocketException:Connection reset
I have set singleUse true and I am using spring integration 4.2.1
This message is emitted when the client closes the socket - if your client only sends one message then closes the socket, you can set singleUse to true and it will suppress this message (as long as the socket is closed normally - between messages).
With Spring Integration version 4.2 and later, the message is not emitted on a normal close, even if singleUse is false.
I've searched quite a bit and been unable to find this: Is there a way that a spring websocket stomp server can disconnect a client based on the sessionId (or really based on anything at all)?
It seems to me that once a client connects to a server there is nothing that allows the server to disconnect the client.
Actually using some workarounds you can achieve what you want.
For that you should do:
Use java configuration (not sure if it is possible with XML config)
Extend your config class from WebSocketMessageBrokerConfigurationSupport and implement WebSocketMessageBrokerConfigurer interface
Create custom sub-protocol websocket handler and extend it from SubProtocolWebSocketHandler class
In your custom sub-protocol websocket handler override afterConnectionEstablished method and you will have access to WebSocketSession :)
I've created sample spring-boot project to show how we can disconnect client session from server side:
https://github.com/isaranchuk/spring-websocket-disconnect
You can also disconnect session by implementing a custom WebSocketHandlerDecorator:
#Configuration
#EnableWebSocketMessageBroker
public class WebSocketConfig<S extends ExpiringSession> extends AbstractSessionWebSocketMessageBrokerConfigurer<S> {
#Override
public void configureWebSocketTransport(final WebSocketTransportRegistration registration) {
registration.addDecoratorFactory(new WebSocketHandlerDecoratorFactory() {
#Override
public WebSocketHandler decorate(final WebSocketHandler handler) {
return new WebSocketHandlerDecorator(handler) {
#Override
public void afterConnectionEstablished(final WebSocketSession session) throws Exception {
session.close(CloseStatus.NOT_ACCEPTABLE);
super.afterConnectionEstablished(session);
}
};
}
});
super.configureWebSocketTransport(registration);
}
#Override
protected void configureStompEndpoints(final StompEndpointRegistry registry) {
registry.addEndpoint("/home")
.setHandshakeHandler(new DefaultHandshakeHandler(
new UndertowRequestUpgradeStrategy() // If you use undertow
// new JettyRequestUpgradeStrategy()
// new TomcatRequestUpgradeStrategy()
))
.withSockJS();
}
}
As far as I know the API doesn't provide what you are looking for, on server-side you can only detect disconnect events. If you want to disconnect a certain client I think you must go for a litte workaround, e.g. this one:
Write a client-side javascript function that is able to trigger a disconnect
As soon as your client is connected to the server, generate a client ID in your javascript and send it to the server. Remember the ID on the client, you'll need it in step (4).
At the time you want the server to disconnect the connection to the specific client (identified by the ID), send a message containing the ID back to the client.
Now your client javascript evaluates the message send from the server and decides to call the disconnect function you wrote in step (1).
Your client disconnects itself.
The workaround is a bit cumbersome but it'll work.
I relied on the idea of #Dániel Kis and implemented the websocket session management with the key point of storing websocket sessions for authenticated users in Singleton-like object.
// WebSocketConfig.java
#Configuration
#EnableWebSocketMessageBroker
public class WebSocketConfig implements WebSocketMessageBrokerConfigurer {
#Override
public void configureWebSocketTransport(WebSocketTransportRegistration registration) {
registration.addDecoratorFactory(new WebSocketHandlerDecoratorFactory() {
#Override
public WebSocketHandler decorate(final WebSocketHandler handler) {
return new WebSocketHandlerDecorator(handler) {
#Override
public void afterConnectionEstablished(final WebSocketSession session) throws Exception {
// We will store current user's session into WebsocketSessionHolder after connection is established
String username = session.getPrincipal().getName();
WebsocketSessionHolder.addSession(username, session);
super.afterConnectionEstablished(session);
}
};
}
});
}
}
Class to store websocket users' sessions WebsocketSessionHolder. I use 'synchronized' blocks for thread safety. Actually this blocks are not expensive operations because each of methods (addSession and closeSessions) are used not so often (On establishing and terminating connection). No need to use ConcurrentHashMap or SynchronizedMap here because we perform bunch of operations with the list in these methods.
// WebsocketSessionHolder.java
public class WebsocketSessionHolder {
static {
sessions = new HashMap<>();
}
// key - username, value - List of user's sessions
private static Map<String, List<WebSocketSession>> sessions;
public static void addSession(String username, WebSocketSession session)
{
synchronized (sessions) {
var userSessions = sessions.get(username);
if (userSessions == null)
userSessions = new ArrayList<WebSocketSession>();
userSessions.add(session);
sessions.put(username, userSessions);
}
}
public static void closeSessions(String username) throws IOException
{
synchronized (sessions) {
var userSessions = sessions.get(username);
if (userSessions != null)
{
for(var session : userSessions) {
// I use POLICY_VIOLATION to indicate reason of disconnecting for a client
session.close(CloseStatus.POLICY_VIOLATION);
}
sessions.remove(username);
}
}
}
}
And the final touch - terminating (disconnecting) specified user websocket sessions ("ADMIN" in the example), say in some Controller
//PageController.java
#Controller
public class PageController {
#GetMapping("/kill-sessions")
public void killSessions() throws Exception {
WebsocketSessionHolder.closeSessions("ADMIN");
}
}
In case of xml configuration you can use <websocket:decorator-factories> in the <websocket:transport> of your <websocket:message-broker>.
Create custom WebSocketHandlerDecorator and WebSocketHandlerDecoratorFactory which implement decorate method.
This may seem brief but I am not certain what the implementation would look like in your case. But, I think there are some circumstances that would warrant this workaround/solution:
Set a timeout on the back-end (say 30 seconds):
This is how you would do it with Spring Boot Websocket (and Tomcat):
#Bean
public ServletServerContainerFactoryBean websocketContainer() {
ServletServerContainerFactoryBean container = new ServletServerContainerFactoryBean();
container.setMaxSessionIdleTimeout(MAX_SESSION_IDLE_TIMEOUT);
return container;
}
If you want to keep the session open - continue to send messages or else actively send ping/pongs. In the case that you want the session to disconnect, stop the ping/pong interaction somewhere suitable in you application.
Of course, if you are wanting to disconnect immediately, this doesn't seem to be an appropriate solution. But if you are simply trying to reduce the number of active connections, ping/pong may be a good fit since it keeps a session open only so long as messages are actively being sent, preventing the session from being closed prematurely.
first you have to introduce a class as your User class by inheritance then use it like this:
if (userObject instanceof User) {
User user = (User) userObject;
if (user.getId().equals(userDTO.getId())) {
for (SessionInformation information : sessionRegistry.getAllSessions(user, true)) {
information.expireNow();
}
}
}
I'm developing a realtime notification system in Spring 4 by using a build-in Message Broker, and STOMP over WebSocket.
I would like to be able to send messages to a specific user, according with his username.
In order to achieve this goal, I'm using the convertAndSendToUser method of org.springframework.messaging.simp.SimpMessagingTemplate class, as follows:
private final MessagingTemplate messagingTemplate;
#Autowired
public LRTStatusListener(SimpMessagingTemplate messagingTemplate) {
this.messagingTemplate = messagingTemplate;
}
#Scheduled(fixedDelay=5000)
public void sendMessages(Principal principal)
messagingTemplate
.convertAndSendToUser(principal.getName(), "/horray", "Horray, " + principal.getName() + "!");
}
As configuration:
#Configuration
#EnableScheduling
#EnableWebSocketMessageBroker
public class WebSocketConfig extends AbstractWebSocketMessageBrokerConfigurer {
#Override
public void registerStompEndpoints(StompEndpointRegistry registry) {
registry.addEndpoint("/notifications").withSockJS();
}
#Override
public void configureMessageBroker(MessageBrokerRegistry registry) {
registry.enableSimpleBroker("/topic", "/queue", "/user");
}
}
Client-side (via JavaScript), I should subscribe to a channel by specifing the username (according with another very similar question: Sending message to specific user on Spring Websocket).
stompClient.subscribe('/user/' + username + '/horray, ...)
This last point sounds weird...
Supposing that I'm logged as w.white on my webapp, by subscribing:
stompClient.subscribe('/user/w.white/horray, ...)
... I will be able to see messages sent to w.white, and this is awesome... But subscribing:
stompClient.subscribe('/user/j.pinkman/horray, ...)
... I will be able to see also messages sent to j.pinkman, despide that I'm currently logged as w.white.
It is a way to overcome this problem?
Update
Below there is the log about the connection over WebSocket:
Opening Web Socket...
Web Socket Opened...
>>> CONNECT
accept-version:1.1,1.0
heart-beat:10000,10000
<<< CONNECTED
user-name:w.white
heart-beat:0,0
version:1.1
connected to server undefined
Connected: CONNECTED
version:1.1
heart-beat:0,0
user-name:w.white
>>> SUBSCRIBE
id:sub-0
destination:/topic/lrt
>>> SUBSCRIBE
id:sub-1
destination:/user/lrt
I found the solution.
First of all, it is important to know that the /user channel is already managed by Spring STOMP, and by the way, no registration is required.
So:
#Override
public void configureMessageBroker(MessageBrokerRegistry registry) {
registry.enableSimpleBroker("/topic", "/queue");
}
Then, I setup the destination channel as /queue/horray:
#Scheduled(fixedDelay=5000)
public void sendMessages(Principal principal)
messagingTemplate
.convertAndSendToUser(principal.getName(), "/queue/horray", "Horray, " + principal.getName() + "!");
}
At last, on client:
stompClient.subscribe('/user/queue/horray', '...');
Now, it works fine! Messages are sent only to the specified recipient, according to the Principal fetched by the security context.
Since users on my application are not authenticated I just used the session Id to differenciate the various topics
on the server:
template.convertAndSend("/topic/warnings/" + sessionId, ...)
And the client is pretty straightforward
stompClient.subscribe('/topic/warnings/${pageContext.session.id}', ...
Maybe not the cleanest way but it works, and without authentication I couldn't make use of /user channel