001/*
002 * Licensed to the Apache Software Foundation (ASF) under one or more
003 * contributor license agreements.  See the NOTICE file distributed with
004 * this work for additional information regarding copyright ownership.
005 * The ASF licenses this file to You under the Apache License, Version 2.0
006 * (the "License"); you may not use this file except in compliance with
007 * the License.  You may obtain a copy of the License at
008 *
009 *      http://www.apache.org/licenses/LICENSE-2.0
010 *
011 * Unless required by applicable law or agreed to in writing, software
012 * distributed under the License is distributed on an "AS IS" BASIS,
013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014 * See the License for the specific language governing permissions and
015 * limitations under the License.
016 */
017
018package org.apache.commons.net.examples.unix;
019
020import java.io.BufferedReader;
021import java.io.IOException;
022import java.io.InputStreamReader;
023import java.io.InterruptedIOException;
024import java.io.OutputStreamWriter;
025import java.io.PrintWriter;
026import java.net.InetAddress;
027import java.net.SocketException;
028import java.nio.charset.Charset;
029import java.time.Duration;
030
031import org.apache.commons.net.echo.EchoTCPClient;
032import org.apache.commons.net.echo.EchoUDPClient;
033
034/**
035 * This is an example program demonstrating how to use the EchoTCPClient and EchoUDPClient classes. This program connects to the default echo service port of a
036 * specified server, then reads lines from standard input, writing them to the echo server, and then printing the echo. The default is to use the TCP port. Use
037 * the -udp flag to use the UDP port.
038 * <p>
039 * Usage: echo [-udp] <hostname>
040 * </p>
041 */
042public final class echo {
043
044    public static void echoTCP(final String host) throws IOException {
045        final EchoTCPClient client = new EchoTCPClient();
046        String line;
047
048        // We want to timeout if a response takes longer than 60 seconds
049        client.setDefaultTimeout(60000);
050        client.connect(host);
051        try {
052            System.out.println("Connected to " + host + ".");
053            final Charset charset = Charset.defaultCharset();
054            final BufferedReader input = new BufferedReader(new InputStreamReader(System.in, charset));
055            try (PrintWriter echoOutput = new PrintWriter(new OutputStreamWriter(client.getOutputStream(), charset), true);
056                    BufferedReader echoInput = new BufferedReader(new InputStreamReader(client.getInputStream(), charset))) {
057                while ((line = input.readLine()) != null) {
058                    echoOutput.println(line);
059                    System.out.println(echoInput.readLine());
060                }
061            }
062            // Don't close System.in
063        } finally {
064            client.disconnect();
065        }
066    }
067
068    public static void echoUDP(final String host) throws IOException {
069        int length, count;
070        byte[] data;
071        String line;
072        final BufferedReader input;
073        final InetAddress address;
074
075        final Charset charset = Charset.defaultCharset();
076        input = new BufferedReader(new InputStreamReader(System.in, charset));
077        address = InetAddress.getByName(host);
078        try (EchoUDPClient client = new EchoUDPClient()) {
079
080            client.open();
081            // If we don't receive an echo within 5 seconds, assume the packet is lost.
082            client.setSoTimeout(Duration.ofSeconds(5));
083            System.out.println("Ready to echo to " + host + ".");
084
085            // Remember, there are no guarantees about the ordering of returned
086            // UDP packets, so there is a chance the output may be jumbled.
087            while ((line = input.readLine()) != null) {
088                data = line.getBytes(charset);
089                client.send(data, address);
090                count = 0;
091                do {
092                    try {
093                        length = client.receive(data);
094                    }
095                    // Here we catch both SocketException and InterruptedIOException,
096                    // because even though the JDK 1.1 docs claim that
097                    // InterruptedIOException is thrown on a timeout, it seems
098                    // SocketException is also thrown.
099                    catch (final SocketException e) {
100                        // We timed out and assume the packet is lost.
101                        System.err.println("SocketException: Timed out and dropped packet");
102                        break;
103                    } catch (final InterruptedIOException e) {
104                        // We timed out and assume the packet is lost.
105                        System.err.println("InterruptedIOException: Timed out and dropped packet");
106                        break;
107                    }
108                    System.out.print(new String(data, 0, length, charset));
109                    count += length;
110                } while (count < data.length);
111
112                System.out.println();
113            }
114
115        }
116    }
117
118    public static void main(final String[] args) {
119
120        if (args.length == 1) {
121            try {
122                echoTCP(args[0]);
123            } catch (final IOException e) {
124                e.printStackTrace();
125                System.exit(1);
126            }
127        } else if (args.length == 2 && args[0].equals("-udp")) {
128            try {
129                echoUDP(args[1]);
130            } catch (final IOException e) {
131                e.printStackTrace();
132                System.exit(1);
133            }
134        } else {
135            System.err.println("Usage: echo [-udp] <hostname>");
136            System.exit(1);
137        }
138
139    }
140
141}