Adding spring websockets demo application.

settings.gradle

@@ -1,2 +1,3 @@
 rootProject.name = 'spring-showcase'
 include ':spring-showcase-web'
+include ':spring-websockets-demo1'

spring-websockets-demo1/.gitignore

@@ -0,0 +1,37 @@
+HELP.md
+.gradle
+build/
+!gradle/wrapper/gradle-wrapper.jar
+!**/src/main/**/build/
+!**/src/test/**/build/
+
+### STS ###
+.apt_generated
+.classpath
+.factorypath
+.project
+.settings
+.springBeans
+.sts4-cache
+bin/
+!**/src/main/**/bin/
+!**/src/test/**/bin/
+
+### IntelliJ IDEA ###
+.idea
+*.iws
+*.iml
+*.ipr
+out/
+!**/src/main/**/out/
+!**/src/test/**/out/
+
+### NetBeans ###
+/nbproject/private/
+/nbbuild/
+/dist/
+/nbdist/
+/.nb-gradle/
+
+### VS Code ###
+.vscode/

spring-websockets-demo1/build.gradle

@@ -0,0 +1,26 @@
+plugins {
+    id 'org.springframework.boot' version '2.4.2'
+    id 'io.spring.dependency-management' version '1.0.11.RELEASE'
+    id 'java'
+}
+
+group = 'ch.tpolgrabia.demos.springshowcase'
+version = '0.0.1-SNAPSHOT'
+sourceCompatibility = '11'
+
+repositories {
+    mavenCentral()
+}
+
+dependencies {
+    implementation 'org.springframework.boot:spring-boot-starter-web'
+    implementation 'org.springframework.boot:spring-boot-starter-websocket'
+    implementation 'org.webjars.npm:sockjs-client:1.5.0'
+    implementation 'org.webjars:stomp-websocket:2.3.3'
+    implementation 'org.webjars.npm:bulma:0.9.1'
+    testImplementation 'org.springframework.boot:spring-boot-starter-test'
+}
+
+test {
+    useJUnitPlatform()
+}

spring-websockets-demo1/src/main/java/ch/tpolgrabia/demos/springshowcase/springwebsocketsdemo1/SpringWebsocketsDemo1Application.java

@@ -0,0 +1,13 @@
+package ch.tpolgrabia.demos.springshowcase.springwebsocketsdemo1;
+
+import org.springframework.boot.SpringApplication;
+import org.springframework.boot.autoconfigure.SpringBootApplication;
+
+@SpringBootApplication
+public class SpringWebsocketsDemo1Application {
+
+    public static void main(String[] args) {
+        SpringApplication.run(SpringWebsocketsDemo1Application.class, args);
+    }
+
+}

spring-websockets-demo1/src/main/java/ch/tpolgrabia/demos/springshowcase/springwebsocketsdemo1/configs/WebsocketsConfig.java

@@ -0,0 +1,22 @@
+package ch.tpolgrabia.demos.springshowcase.springwebsocketsdemo1.configs;
+
+import org.springframework.context.annotation.Configuration;
+import org.springframework.messaging.simp.config.MessageBrokerRegistry;
+import org.springframework.web.socket.config.annotation.EnableWebSocketMessageBroker;
+import org.springframework.web.socket.config.annotation.StompEndpointRegistry;
+import org.springframework.web.socket.config.annotation.WebSocketMessageBrokerConfigurer;
+
+@Configuration
+@EnableWebSocketMessageBroker
+public class WebsocketsConfig implements WebSocketMessageBrokerConfigurer {
+    @Override
+    public void configureMessageBroker(MessageBrokerRegistry registry) {
+        registry.enableSimpleBroker("/topic");
+        registry.setApplicationDestinationPrefixes("/app");
+    }
+
+    @Override
+    public void registerStompEndpoints(StompEndpointRegistry registry) {
+        registry.addEndpoint("/gs-guide-websocket").withSockJS();
+    }
+}

spring-websockets-demo1/src/main/java/ch/tpolgrabia/demos/springshowcase/springwebsocketsdemo1/controllers/WebsocketController.java

@@ -0,0 +1,16 @@
+package ch.tpolgrabia.demos.springshowcase.springwebsocketsdemo1.controllers;
+
+import ch.tpolgrabia.demos.springshowcase.springwebsocketsdemo1.models.Greeting;
+import ch.tpolgrabia.demos.springshowcase.springwebsocketsdemo1.models.HelloMessage;
+import org.springframework.messaging.handler.annotation.MessageMapping;
+import org.springframework.messaging.handler.annotation.SendTo;
+import org.springframework.stereotype.Controller;
+
+@Controller
+public class WebsocketController {
+    @MessageMapping("/hello")
+    @SendTo("/topic/greetings")
+    public Greeting greeting(HelloMessage message) {
+        return new Greeting(String.format("Hello %s!!!", message.getName()));
+    }
+}

spring-websockets-demo1/src/main/java/ch/tpolgrabia/demos/springshowcase/springwebsocketsdemo1/models/Greeting.java

@@ -0,0 +1,17 @@
+package ch.tpolgrabia.demos.springshowcase.springwebsocketsdemo1.models;
+
+public class Greeting {
+    private String content;
+
+    public Greeting(String content) {
+        this.content = content;
+    }
+
+    public String getContent() {
+        return content;
+    }
+
+    public void setContent(String content) {
+        this.content = content;
+    }
+}

spring-websockets-demo1/src/main/java/ch/tpolgrabia/demos/springshowcase/springwebsocketsdemo1/models/HelloMessage.java

@@ -0,0 +1,13 @@
+package ch.tpolgrabia.demos.springshowcase.springwebsocketsdemo1.models;
+
+public class HelloMessage {
+    private String name;
+
+    public String getName() {
+        return name;
+    }
+
+    public void setName(String name) {
+        this.name = name;
+    }
+}

spring-websockets-demo1/src/main/resources/application.properties

@@ -0,0 +1 @@
+

spring-websockets-demo1/src/main/resources/static/app.js

@@ -0,0 +1,34 @@
+window.addEventListener('DOMContentLoaded', (event) => {
+    // let sockJs = new SockJS('/gs-guide-websocket');
+    let sockJs = new SockJS('/gs-guide-websocket');
+    let stompClient = Stomp.over(sockJs);
+    stompClient.connect('', '', (frame) => {
+        console.log(`Connected to ${frame}`);
+        stompClient.subscribe('/topic/greetings', function (greeting) {
+            console.log(`Got greeting: ${greeting}`);
+
+            let el = document.querySelector("#messages > tbody");
+            console.log('Got', el);
+            let tr = document.createElement('tr');
+            let td1 = document.createElement('td');
+            let td2 = document.createElement('td');
+            let message = JSON.parse(greeting.body);
+            td1.textContent = new Date().toISOString();
+            td2.textContent = message.content;
+
+            tr.append(td1);
+            tr.append(td2);
+            el.append(tr);
+        });
+    });
+
+    document.querySelector('#submit-message')
+        .addEventListener('click', (e) => {
+            let messageContentNode = document.querySelector('#message-content');
+            let messageValue = messageContentNode.value;
+            messageContentNode.value = '';
+            stompClient.send('/app/hello', {}, JSON.stringify({
+                name: messageValue
+            }));
+        });
+});

spring-websockets-demo1/src/main/resources/static/index.html

@@ -0,0 +1,42 @@
+<!DOCTYPE html>
+<html lang="en">
+<head>
+    <meta charset="UTF-8"/>
+    <title>Showcas for simple websocket messaging</title>
+    <link rel="stylesheet" href="/webjars/bulma/0.9.1/css/bulma.min.css"/>
+</head>
+<body>
+<div class="container">
+    <div class="field">
+        <label class="label">Message</label>
+        <div class="control">
+            <input id="message-content" type="text" class="input" placeholder="Message"/>
+        </div>
+    </div>
+
+    <div class="field is-grouped">
+        <div class="control">
+            <button id="submit-message" class="button is-link">Submit</button>
+        </div>
+    </div>
+</div>
+
+<div class="container">
+    <table id="messages" class="table is-striped is-fullwidth">
+        <thead>
+        <tr>
+            <th>Time</th>
+            <th>Message</th>
+        </tr>
+        </thead>
+        <tbody>
+
+        </tbody>
+    </table>
+</div>
+
+<script src="/webjars/sockjs-client/1.5.0/dist/sockjs.js"></script>
+<script src="/webjars/stomp-websocket/2.3.3/stomp.js"></script>
+<script type="application/javascript" src="/app.js"></script>
+</body>
+</html>

spring-websockets-demo1/src/test/java/ch/tpolgrabia/demos/springshowcase/springwebsocketsdemo1/SpringWebsocketsDemo1ApplicationTests.java

@@ -0,0 +1,13 @@
+package ch.tpolgrabia.demos.springshowcase.springwebsocketsdemo1;
+
+import org.junit.jupiter.api.Test;
+import org.springframework.boot.test.context.SpringBootTest;
+
+@SpringBootTest
+class SpringWebsocketsDemo1ApplicationTests {
+
+    @Test
+    void contextLoads() {
+    }
+
+}