Changes for WebRTC (BAEL-3198) (#8213)

* Adding webrtc changes

* formatting

* formatting pom

* formatting

* Adding space instead of tabs for indentation

* formatting changes

* Updating tabs to spaces

pom.xml

@@ -635,6 +635,7 @@
                 <module>spring-boot-nashorn</module>
                 <module>java-blockchain</module>
                 <module>machine-learning</module>
+                <module>webrtc</module>
                 <module>wildfly</module>
                 <module>quarkus-extension</module>
             </modules>
@@ -883,7 +884,6 @@
 
                 <module>spring-boot-nashorn</module>
                 <module>java-blockchain</module>
-
             </modules>
 
         </profile>

webrtc/pom.xml

@@ -0,0 +1,37 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project xmlns="http://maven.apache.org/POM/4.0.0"
+    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+    xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
+    <modelVersion>4.0.0</modelVersion>
+
+    <artifactId>webrtc</artifactId>
+    <version>0.0.1</version>
+
+    <parent>
+        <artifactId>parent-boot-2</artifactId>
+        <groupId>com.baeldung</groupId>
+        <version>0.0.1-SNAPSHOT</version>
+        <relativePath>../parent-boot-2</relativePath>
+    </parent>
+
+    <dependencies>
+        <dependency>
+            <groupId>org.springframework.boot</groupId>
+            <artifactId>spring-boot-starter-websocket</artifactId>
+        </dependency>
+    </dependencies>
+
+    <properties>
+        <java.version>1.8</java.version>
+    </properties>
+
+    <build>
+        <plugins>
+            <plugin>
+                <groupId>org.springframework.boot</groupId>
+                <artifactId>spring-boot-maven-plugin</artifactId>
+            </plugin>
+        </plugins>
+    </build>
+
+</project>

webrtc/src/main/java/com/baeldung/webrtc/SocketHandler.java

@@ -0,0 +1,31 @@
+package com.baeldung.webrtc;
+
+import org.springframework.stereotype.Component;
+import org.springframework.web.socket.TextMessage;
+import org.springframework.web.socket.WebSocketSession;
+import org.springframework.web.socket.handler.TextWebSocketHandler;
+
+import java.io.IOException;
+import java.util.List;
+import java.util.concurrent.CopyOnWriteArrayList;
+
+@Component
+public class SocketHandler extends TextWebSocketHandler {
+
+    List<WebSocketSession> sessions = new CopyOnWriteArrayList<>();
+
+    @Override
+    public void handleTextMessage(WebSocketSession session, TextMessage message) throws InterruptedException, IOException {
+
+        for (WebSocketSession webSocketSession : sessions) {
+            if (webSocketSession.isOpen() && !session.getId().equals(webSocketSession.getId())) {
+                webSocketSession.sendMessage(message);
+            }
+        }
+    }
+
+    @Override
+    public void afterConnectionEstablished(WebSocketSession session) throws Exception {
+        sessions.add(session);
+    }
+}

webrtc/src/main/java/com/baeldung/webrtc/WebRTCDemoApplication.java

@@ -0,0 +1,12 @@
+package com.baeldung.webrtc;
+
+import org.springframework.boot.SpringApplication;
+import org.springframework.boot.autoconfigure.SpringBootApplication;
+
+@SpringBootApplication
+public class WebRTCDemoApplication {
+
+    public static void main(String[] args) {
+        SpringApplication.run(WebRTCDemoApplication.class, args);
+    }
+}

webrtc/src/main/java/com/baeldung/webrtc/WebSocketConfiguration.java

@@ -0,0 +1,17 @@
+package com.baeldung.webrtc;
+
+import org.springframework.context.annotation.Configuration;
+import org.springframework.web.socket.config.annotation.EnableWebSocket;
+import org.springframework.web.socket.config.annotation.WebSocketConfigurer;
+import org.springframework.web.socket.config.annotation.WebSocketHandlerRegistry;
+
+@Configuration
+@EnableWebSocket
+public class WebSocketConfiguration implements WebSocketConfigurer {
+
+    @Override
+    public void registerWebSocketHandlers(WebSocketHandlerRegistry registry) {
+        registry.addHandler(new SocketHandler(), "/socket")
+            .setAllowedOrigins("*");
+    }
+}

webrtc/src/main/resources/static/client.js

@@ -0,0 +1,116 @@
+//connecting to our signaling server 
+var conn = new WebSocket('ws://localhost:8080/socket');
+
+conn.onopen = function() {
+    console.log("Connected to the signaling server");
+    initialize();
+};
+
+conn.onmessage = function(msg) {
+    console.log("Got message", msg.data);
+    var content = JSON.parse(msg.data);
+    var data = content.data;
+    switch (content.event) {
+    // when somebody wants to call us
+    case "offer":
+        handleOffer(data);
+        break;
+    case "answer":
+        handleAnswer(data);
+        break;
+    // when a remote peer sends an ice candidate to us
+    case "candidate":
+        handleCandidate(data);
+        break;
+    default:
+        break;
+    }
+};
+
+function send(message) {
+    conn.send(JSON.stringify(message));
+}
+
+var peerConnection;
+var dataChannel;
+var input = document.getElementById("messageInput");
+
+function initialize() {
+    var configuration = null;
+
+    peerConnection = new RTCPeerConnection(configuration, {
+        optional : [ {
+            RtpDataChannels : true
+        } ]
+    });
+
+    // Setup ice handling
+    peerConnection.onicecandidate = function(event) {
+        if (event.candidate) {
+            send({
+                event : "candidate",
+                data : event.candidate
+            });
+        }
+    };
+
+    // creating data channel
+    dataChannel = peerConnection.createDataChannel("dataChannel", {
+        reliable : true
+    });
+
+    dataChannel.onerror = function(error) {
+        console.log("Error occured on datachannel:", error);
+    };
+
+    // when we receive a message from the other peer, printing it on the console
+    dataChannel.onmessage = function(event) {
+        console.log("message:", event.data);
+    };
+
+    dataChannel.onclose = function() {
+        console.log("data channel is closed");
+    };
+}
+
+function createOffer() {
+    peerConnection.createOffer(function(offer) {
+        send({
+            event : "offer",
+            data : offer
+        });
+        peerConnection.setLocalDescription(offer);
+    }, function(error) {
+        alert("Error creating an offer");
+    });
+}
+
+function handleOffer(offer) {
+    peerConnection.setRemoteDescription(new RTCSessionDescription(offer));
+
+    // create and send an answer to an offer
+    peerConnection.createAnswer(function(answer) {
+        peerConnection.setLocalDescription(answer);
+        send({
+            event : "answer",
+            data : answer
+        });
+    }, function(error) {
+        alert("Error creating an answer");
+    });
+
+};
+
+function handleCandidate(candidate) {
+    peerConnection.addIceCandidate(new RTCIceCandidate(candidate));
+};
+
+function handleAnswer(answer) {
+    peerConnection.setRemoteDescription(new RTCSessionDescription(answer));
+    console.log("connection established successfully!!");
+};
+
+function sendMessage() {
+    dataChannel.send(input.value);
+    input.value = "";
+}

webrtc/src/main/resources/static/index.html

@@ -0,0 +1,67 @@
+<html>
+
+<head>
+<title>WebRTC demo</title>
+<!--Bootstrap only for styling-->
+<link rel="stylesheet"
+ href="https://maxcdn.bootstrapcdn.com/bootstrap/3.4.0/css/bootstrap.min.css">
+<script
+ src="https://ajax.googleapis.com/ajax/libs/jquery/3.4.1/jquery.min.js"></script>
+<script
+ src="https://maxcdn.bootstrapcdn.com/bootstrap/3.4.0/js/bootstrap.min.js"></script>
+<!--Bootstrap only for styling-->
+</head>
+<style>
+.container {
+    background: rgb(148, 144, 144);
+    margin: 50px auto;
+    max-width: 80%;
+    text-align: center;
+    padding: 2%;
+}
+
+button {
+    margin: 1em;
+}
+
+input {
+    margin-top: 1em;
+}
+
+.footer {
+    background: rgb(148, 144, 144);
+    text-align: center;
+    padding: 2%;
+    position: absolute;
+    bottom: 0;
+    width: 100%;
+}
+</style>
+
+<body>
+
+ <div class="container">
+  <h1>A Demo for messaging in WebRTC</h1>
+
+  <h3>
+   Run two instances of this webpage along with the server to test this
+   application.<br> Create an offer, and then send the message. <br>Check
+   the browser console to see the output.
+  </h3>
+
+  <!--WebRTC related code-->
+  <button type="button" class="btn btn-primary" onclick='createOffer()'>Create
+   Offer</button>
+  <input id="messageInput" type="text" class="form-control"
+   placeholder="message">
+  <button type="button" class="btn btn-primary" onclick='sendMessage()'>SEND</button>
+  <script src="client.js"></script>
+  <!--WebRTC related code-->
+
+ </div>
+ <div class="footer">This application is intentionally made simple
+  to avoid cluttering with non WebRTC related code.</div>
+
+</body>
+
+</html>