spring-web-socket-chat

Sample chat application with spring web socket, Sock Js and Stomp protocol

This application demonstrates the usage of spring-websocket and stomp protocol to build a simple chat application. Shows examples for basic websocket messaging without stomp and sock js, group broadcasting message using stomp and sock js, user-to-user chat with spring security authentication, websocket java client implementation using spring-boot and java swing and also an out-of-topic example to push notifications using EventSources, SseEmitters.

Refer end of the README file to get deployment info

Basic websocket chat

spring.websocket.chat.config.WebSocketConfig, and webSocketChat.jsp provides example for this.

Need to create @Configuration class with @EnableWebSocket annotation implementing interface org.springframework.web.socket.config.annotation.WebSocketConfigurer, a handler implementing org.springframework.web.socket.WebSocketHandler interface and register the end point with the handler.

        @Override
        public void afterConnectionEstablished(WebSocketSession session) throws Exception {
            sessions.add(session);
            super.afterConnectionEstablished(session);
        }

        @Override
        protected void handleTextMessage(WebSocketSession session, TextMessage message) throws Exception {
            super.handleTextMessage(session, message);
            sessions.forEach(webSocketSession -> {
                try {
                    webSocketSession.sendMessage(message);
                } catch (IOException e) {
                    LOGGER.error("Error occurred.", e);
                }
            });
        }

Group chat with Stomp and Sock Js

A sample group ‘topic’ chat using stomp protocol and sock js failover mechanisms.

Need to create a @Configuration class with @EnableWebSocketMessageBroker and implement org.springframework.web.socket.config.annotation register the end-points. Can handle messages using @MessageMapping("/endpoint") @SendTo("/topic/messages") annotated methods in the controller. See WebSocketSockJsBrokerConfig, MessageBroadcastController and sockJsGrpChat.jsp.

    @MessageMapping("/grp-chat")
    @SendTo("/topic/messages")
    public OutputMessage send(ChatMessage chatMessage) throws Exception {
        String time = CommonUtils.getCurrentTimeStamp();
        return new OutputMessage(chatMessage.getFrom(), chatMessage.getText(), time, false);
    }

Jackson mapper library should be in the classpath to serialize return object into Json.

User-to-user chat with Stomp, Sock Js and Spring security

A private chat application using stomp and sock js as previous and spring security for authentication. See WebSocketSockJsBrokerConfig, SecurityConfig and MessageForwardController.

    @Autowired
    private SimpMessagingTemplate webSocket;

    @MessageMapping("/chat")
    public void send(Message<ChatMessage> message, @Payload ChatMessage chatMessage) throws Exception {
        String time = CommonUtils.getCurrentTimeStamp();

        webSocket.convertAndSendToUser(chatMessage.getRecipient(), "/queue/messages",
                new OutputMessage(chatMessage.getFrom(), chatMessage.getText(), time, false));

    }

Can send to specific authenticated user using SimpMessagingTemplate#convertAndSendToUser.

Websocket Java client

Java-web-socket-client module implements this. Uses Java swing for the presentation and spring-boot for the server. Exchanges messages using websocket stomp protocol from Java environment. See SockJsJavaClient.

Server push notifications using EventSource API

An additional example from websocket to demonstrate usage of EventSource API. Spring provides org.springframework.web.servlet.mvc.method.annotation.SseEmitter for HTML 5 Javascript EventSource API. See PushNotificationController.

    sseEmitter.send(SseEmitter.event().name("group1").data(data));

Note: This is not categorized under spring websocket even though this sample implementation contained.

Deployment information

Tested environment

1. Java version: JDK 8
2. Servlet container: Apache Tomcat 8.5.15
3. Build tool: Maven

Deploying steps

Main project and server

1. cd into project.
2. Build project with mvn install
3. Copy server/target/sample-chat.war into tomcat server.
4. Run tomcat.
5. Visit http://localhost:{tomcat-port}/sample-chat/ from browser.

Java client

1. Build main project. (since server and java client both uses ‘model’ module)
2. cd into java-web-sock-client.
3. Run app using mvn spring-boot:run.