Add Reactor Netty version of secure chat server example #761

Provide a corresponding Reactor Netty version of Secure chat server example as found
in Netty project.

reactor-netty-examples/src/main/java/reactor/netty/examples/tcp/securechat/SecureChatClient.java

@@ -0,0 +1,70 @@
+/*
+ * Copyright (c) 2023 VMware, Inc. or its affiliates, All Rights Reserved.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *   https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package reactor.netty.examples.tcp.securechat;
+
+import java.nio.charset.StandardCharsets;
+import java.util.Scanner;
+
+import io.netty.handler.codec.DelimiterBasedFrameDecoder;
+import io.netty.handler.codec.Delimiters;
+import io.netty.handler.ssl.util.InsecureTrustManagerFactory;
+import reactor.core.publisher.Mono;
+import reactor.netty.Connection;
+import reactor.netty.tcp.TcpClient;
+import reactor.netty.tcp.TcpSslContextSpec;
+
+public class SecureChatClient {
+
+	private static final String HOST = System.getProperty("host", "127.0.0.1");
+
+	private static final int PORT = Integer.parseInt(System.getProperty("port", "8992"));
+
+	private static final boolean WIRETAP = System.getProperty("wiretap") != null;
+
+	public static void main(String[] args) {
+		TcpSslContextSpec tcpSslContextSpec = TcpSslContextSpec.forClient()
+				.configure(builder -> builder.trustManager(InsecureTrustManagerFactory.INSTANCE));
+
+		TcpClient client = TcpClient.create()
+				.host(HOST)
+				.port(PORT)
+				.wiretap(WIRETAP)
+				.doOnConnected(connection -> {
+					connection.addHandlerLast(new DelimiterBasedFrameDecoder(8192, Delimiters.lineDelimiter()));
+				}).secure(spec -> spec.sslContext(tcpSslContextSpec));
+
+		Connection conn = client.connectNow();
+		conn.inbound()
+				.receive()
+				.asString()
+				.subscribe(System.out::println);
+
+		Scanner scanner = new Scanner(System.in, StandardCharsets.UTF_8.name());
+		while (scanner.hasNext()) {
+			String text = scanner.nextLine();
+			conn.outbound().sendString(Mono.just(text + "\r\n"))
+					.then()
+					.subscribe();
+
+			if ("bye".equalsIgnoreCase(text)) {
+				break;
+			}
+		}
+
+		conn.onDispose().block();
+
+	}
+}

reactor-netty-examples/src/main/java/reactor/netty/examples/tcp/securechat/SecureChatServer.java

@@ -0,0 +1,99 @@
+/*
+ * Copyright (c) 2023 VMware, Inc. or its affiliates, All Rights Reserved.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *   https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package reactor.netty.examples.tcp.securechat;
+
+import java.net.InetAddress;
+import java.net.UnknownHostException;
+import java.security.cert.CertificateException;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.concurrent.ConcurrentHashMap;
+
+import javax.net.ssl.SSLSession;
+
+import io.netty.channel.ChannelId;
+import io.netty.handler.codec.DelimiterBasedFrameDecoder;
+import io.netty.handler.codec.Delimiters;
+import io.netty.handler.ssl.SslHandler;
+import io.netty.handler.ssl.util.SelfSignedCertificate;
+import reactor.core.publisher.Flux;
+import reactor.core.publisher.Mono;
+import reactor.netty.Connection;
+import reactor.netty.tcp.TcpServer;
+import reactor.netty.tcp.TcpSslContextSpec;
+
+public class SecureChatServer {
+
+	private static final int PORT = Integer.parseInt(System.getProperty("port", "8992"));
+
+	private static final boolean WIRETAP = System.getProperty("wiretap") != null;
+
+	public static void main(String[] args) throws UnknownHostException, CertificateException {
+		ConcurrentHashMap<ChannelId, Connection> conns = new ConcurrentHashMap<>();
+		String hostname = InetAddress.getLocalHost().getHostName();
+
+		TcpServer server = TcpServer.create()
+				.port(PORT)
+				.wiretap(WIRETAP)
+				.doOnConnection(connection -> {
+					// cache the new connection. it'll be needed later
+					// when the server broadcasts messages from other clients.
+					ChannelId id = connection.channel().id();
+					conns.put(id, connection);
+					connection.addHandlerLast(new DelimiterBasedFrameDecoder(8192, Delimiters.lineDelimiter()));
+					connection.onDispose(() -> conns.remove(id));
+				}).handle((in, out) -> {
+					List<String> welcomeTexts = new ArrayList<>();
+					welcomeTexts.add("Welcome to " + hostname + " secure chat service!\n");
+					in.withConnection(connection -> {
+						SslHandler handler = connection.channel().pipeline().get(SslHandler.class);
+						SSLSession session = handler.engine().getSession();
+						String cipherSuite = session.getCipherSuite();
+						String msg = "Your session is protected by " + cipherSuite + " cipher suite.\n";
+						welcomeTexts.add(msg);
+					});
+
+					Flux<String> welcomeFlux = Flux.fromIterable(welcomeTexts);
+
+					Flux<String> flux = in.receive()
+							.asString()
+							.takeUntil("bye"::equalsIgnoreCase)
+							.handle((text, sink) -> {
+								in.withConnection(current -> {
+									for (Connection conn : conns.values()) {
+										if (conn == current) {
+											sink.next(text);
+										}
+										else {
+											String msg = "[" + conn.channel().remoteAddress() + "] " + text + '\n';
+
+											conn.outbound().sendString(Mono.just(msg)).then().subscribe();
+										}
+									}
+								});
+							})
+							.map(msg -> "[you] " + msg + '\n');
+
+
+					return out.sendString(Flux.concat(welcomeFlux, flux));
+
+				});
+
+		SelfSignedCertificate ssc = new SelfSignedCertificate();
+		server = server.secure(spec -> spec.sslContext(TcpSslContextSpec.forServer(ssc.certificate(), ssc.privateKey())));
+		server.bindNow().onDispose().block();
+	}
+}