Sample Implementation of Websocket Implementation

src/main/java/com/idetix/hostbackend/Controller/GreetingController.java

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+package com.idetix.hostbackend.Controller;
+
+import com.idetix.hostbackend.Messages.Greeting;
+import com.idetix.hostbackend.Messages.HelloMessage;
+import org.springframework.messaging.handler.annotation.MessageMapping;
+import org.springframework.messaging.handler.annotation.SendTo;
+import org.springframework.messaging.simp.annotation.SendToUser;
+import org.springframework.stereotype.Controller;
+
+@Controller
+public class GreetingController {
+    @MessageMapping("/hello")
+    @SendToUser("/topic/greetings")
+    public Greeting greeting(HelloMessage message) throws Exception{
+        Thread.sleep(1000);
+        return new Greeting("Hello, "+ message.getName() + "!");
+    }
+
+//    @MessageMapping("/hello")
+//    @SendTo("/topic/greetings")
+//    public Greeting greeting(HelloMessage message) throws Exception{
+//        Thread.sleep(1000);
+//        return new Greeting("Hello, "+ message.getName() + "!");
+//    }
+
+
+}

src/main/java/com/idetix/hostbackend/HostbackendApplication.java

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+package com.idetix.hostbackend;
+
+import org.springframework.boot.SpringApplication;
+import org.springframework.boot.autoconfigure.SpringBootApplication;
+import org.springframework.scheduling.annotation.EnableScheduling;
+
+@SpringBootApplication
+@EnableScheduling
+public class HostbackendApplication {
+
+	public static void main(String[] args) {
+		SpringApplication.run(HostbackendApplication.class, args);
+	}
+
+}

src/main/java/com/idetix/hostbackend/Messages/Greeting.java

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+package com.idetix.hostbackend.Messages;
+
+import lombok.AllArgsConstructor;
+import lombok.Data;
+import lombok.NoArgsConstructor;
+
+@Data
+@AllArgsConstructor
+@NoArgsConstructor
+public class Greeting {
+    private String content;
+
+}

src/main/java/com/idetix/hostbackend/Messages/HelloMessage.java

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+package com.idetix.hostbackend.Messages;
+
+import lombok.AllArgsConstructor;
+import lombok.Data;
+import lombok.NoArgsConstructor;
+
+@Data
+@AllArgsConstructor
+@NoArgsConstructor
+public class HelloMessage {
+
+    private String name;
+}

src/main/java/com/idetix/hostbackend/WebSocketBrokerConfig.java

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+package com.idetix.hostbackend;
+
+
+
+import org.springframework.context.annotation.Configuration;
+import org.springframework.http.server.ServerHttpRequest;
+import org.springframework.http.server.ServerHttpResponse;
+import org.springframework.http.server.ServletServerHttpRequest;
+import org.springframework.messaging.simp.config.MessageBrokerRegistry;
+import org.springframework.web.socket.WebSocketHandler;
+import org.springframework.web.socket.config.annotation.EnableWebSocketMessageBroker;
+import org.springframework.web.socket.config.annotation.StompEndpointRegistry;
+import org.springframework.web.socket.config.annotation.WebSocketMessageBrokerConfigurer;
+import org.springframework.web.socket.server.support.DefaultHandshakeHandler;
+
+import javax.servlet.http.HttpSession;
+import java.util.Map;
+
+@Configuration
+@EnableWebSocketMessageBroker
+public class WebSocketBrokerConfig implements WebSocketMessageBrokerConfigurer {
+
+    @Override
+    public void configureMessageBroker (MessageBrokerRegistry config) {
+        config.enableSimpleBroker("/topic");
+        config.setApplicationDestinationPrefixes("/app");
+    }
+
+    @Override
+    public void registerStompEndpoints(StompEndpointRegistry registry) {
+        registry
+                .addEndpoint("/host-backend")
+                .setHandshakeHandler(new DefaultHandshakeHandler(){
+                    public boolean beforeHandshake(
+                            ServerHttpRequest request,
+                            ServerHttpResponse response,
+                            WebSocketHandler wsHandler,
+                            Map attributes) throws Exception{
+
+                        if (request instanceof ServletServerHttpRequest){
+                            ServletServerHttpRequest servletRequest
+                            = (ServletServerHttpRequest) request;
+                            HttpSession session = servletRequest
+                            .getServletRequest().getSession();
+                            attributes.put("sessionId", session.getId());
+                        }
+                        return true;
+                    }
+                }).withSockJS();
+    }
+}

src/main/resources/static/app.js

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+var stompClient = null;
+
+function setConnected(connected) {
+    $("#connect").prop("disabled", connected);
+    $("#disconnect").prop("disabled", !connected);
+    if (connected) {
+        $("#conversation").show();
+    }
+    else {
+        $("#conversation").hide();
+    }
+    $("#greetings").html("");
+}
+
+function connect() {
+    var socket = new SockJS('/host-backend');
+    stompClient = Stomp.over(socket);
+    stompClient.connect({}, function (frame) {
+        setConnected(true);
+        console.log('Connected: ' + frame);
+         stompClient.subscribe('/user/topic/greetings', function (greeting) {
+             showGreeting(JSON.parse(greeting.body).content);
+        });
+    });
+}
+
+function disconnect() {
+    if (stompClient !== null) {
+        stompClient.disconnect();
+    }
+    setConnected(false);
+    console.log("Disconnected");
+}
+
+function sendName() {
+    stompClient.send("/app/hello", {}, JSON.stringify({'name': $("#name").val()}));
+}
+
+function showGreeting(message) {
+    $("#greetings").append("<tr><td>" + message + "</td></tr>");
+}
+
+$(function () {
+    $("form").on('submit', function (e) {
+        e.preventDefault();
+    });
+    $( "#connect" ).click(function() { connect(); });
+    $( "#disconnect" ).click(function() { disconnect(); });
+    $( "#send" ).click(function() { sendName(); });
+});

src/main/resources/static/index.html

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+<!DOCTYPE html>
+<html>
+<head>
+    <title>Hello WebSocket</title>
+    <link href="/webjars/bootstrap/css/bootstrap.min.css" rel="stylesheet">
+    <link href="/main.css" rel="stylesheet">
+    <script src="/webjars/jquery/jquery.min.js"></script>
+    <script src="/webjars/sockjs-client/sockjs.min.js"></script>
+    <script src="/webjars/stomp-websocket/stomp.min.js"></script>
+    <script src="/app.js"></script>
+</head>
+<body>
+<noscript><h2 style="color: #ff0000">Seems your browser doesn't support Javascript! Websocket relies on Javascript being
+    enabled. Please enable
+    Javascript and reload this page!</h2></noscript>
+<div id="main-content" class="container">
+    <div class="row">
+        <div class="col-md-6">
+            <form class="form-inline">
+                <div class="form-group">
+                    <label for="connect">WebSocket connection:</label>
+                    <button id="connect" class="btn btn-default" type="submit">Connect</button>
+                    <button id="disconnect" class="btn btn-default" type="submit" disabled="disabled">Disconnect
+                    </button>
+                </div>
+            </form>
+        </div>
+        <div class="col-md-6">
+            <form class="form-inline">
+                <div class="form-group">
+                    <label for="name">What is your name?</label>
+                    <input type="text" id="name" class="form-control" placeholder="Your name here...">
+                </div>
+                <button id="send" class="btn btn-default" type="submit">Send</button>
+            </form>
+        </div>
+    </div>
+    <div class="row">
+        <div class="col-md-12">
+            <table id="conversation" class="table table-striped">
+                <thead>
+                <tr>
+                    <th>Greetings</th>
+                </tr>
+                </thead>
+                <tbody id="greetings">
+                </tbody>
+            </table>
+        </div>
+    </div>
+</div>
+</body>
+</html>

src/test/java/com/idetix/hostbackend/HostbackendApplicationTests.java

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+package com.idetix.hostbackend;
+
+class HostbackendApplicationTests {
+
+}