SecureEchoClient.java

/*
 * Copyright 2015 Netflix, Inc.
 *
 * 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
 *
 *     http://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 io.reactivex.netty.examples.tcp.secure;

import io.netty.buffer.ByteBuf;
import io.netty.handler.logging.LogLevel;
import io.reactivex.netty.examples.ExamplesEnvironment;
import io.reactivex.netty.examples.tcp.echo.EchoServer;
import io.reactivex.netty.protocol.tcp.client.TcpClient;
import org.slf4j.Logger;
import rx.Observable;

import java.net.SocketAddress;
import java.nio.charset.Charset;

/**
 * A secure TCP "Hello World" example that sends a string "Hello World!" to the target server and expects an echo
 * response.
 *
 * There are three ways of running this example:
 *
 * <h2>Default</h2>
 *
 * The default way is to just run this class with no arguments, which will start a server ({@link EchoServer}) on
 * an ephemeral port, send a "Hello World!" message to the server and print the response.
 *
 * <h2>After starting {@link SecureEchoServer}</h2>
 *
 * If you want to see how {@link SecureEchoServer} work, you can run {@link SecureEchoServer} by yourself and then pass
 * the port on which the server started to this class as a program argument:
 *
 <PRE>
 java io.reactivex.netty.examples.tcp.secure.SecureEchoClient [server port]
 </PRE>
 *
 * <h2>Existing TCP server</h2>
 *
 * You can also use this client to connect to an already running TCP server (different than
 * {@link SecureEchoServer}) by passing the port and host of the existing server similar to the case above:
 *
 <PRE>
 java io.reactivex.netty.examples.tcp.secure.SecureEchoClient [server port] [server host]
 </PRE>
 * If the server host is omitted from the above, it defaults to "127.0.0.1"
 *
 * In all the above usages, this client will print the response received from the server.
 *
 * @see EchoServer Default server for this client.
 */
public final class SecureEchoClient {

    public static void main(String[] args) {

        ExamplesEnvironment env = ExamplesEnvironment.newEnvironment(SecureEchoClient.class);

        /*
         * Retrieves the server address, using the following algorithm:
         * <ul>
             <li>If any arguments are passed, then use the first argument as the server port.</li>
             <li>If available, use the second argument as the server host, else default to localhost</li>
             <li>Otherwise, start the passed server class and use that address.</li>
         </ul>
         */
        SocketAddress serverAddress = env.getServerAddress(SecureEchoServer.class, args);
        Logger logger = env.getLogger();

        /*Create a new client for the server address*/
        TcpClient.newClient(serverAddress)
                 .enableWireLogging("secure-client", LogLevel.DEBUG)
                 .unsafeSecure()
                 .createConnectionRequest()
                 .flatMap(connection ->
                                  connection.writeString(Observable.just("Hello World!"))
                                          .cast(ByteBuf.class)
                                          .concatWith(connection.getInput())
                 )
                .take(1)
                .map(bb -> bb.toString(Charset.defaultCharset()))
                .toBlocking()
                .forEach(logger::info);
    }
}