com.comcast.cats.recorder.TelnetHandler.java Source code

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Here is the source code for com.comcast.cats.recorder.TelnetHandler.java

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/**
 * Copyright 2014 Comcast Cable Communications Management, LLC
 *
 * This file is part of CATS.
 *
 * CATS is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * CATS is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with CATS.  If not, see <http://www.gnu.org/licenses/>.
 */
package com.comcast.cats.recorder;

import java.io.IOException;
import java.io.InputStream;
import java.io.PrintStream;
import java.net.SocketException;

import org.apache.commons.net.telnet.TelnetClient;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import com.comcast.cats.info.VideoRecorderServiceConstants;
import com.comcast.cats.recorder.exception.VideoRecorderConnectionException;

/**
 * A utility class to manage VLC through telnet interface for video recorder.
 * 
 * @author ssugun00c
 * 
 */
public class TelnetHandler {
    static {
        telnetPassword = System.getProperty(VideoRecorderServiceConstants.SYSTEM_PROPERTY_VLC_TELNET_PASSWORD);
        telnetHost = System.getProperty(VideoRecorderServiceConstants.SYSTEM_PROPERTY_VLC_TELNET_HOST);
    }

    private TelnetClient telnet = new TelnetClient();
    private InputStream in;
    private PrintStream out;
    private char prompt = '>';
    private static String telnetHost;
    private static String telnetPassword;

    private static Logger LOGGER = LoggerFactory.getLogger(TelnetHandler.class);

    /**
     * Connect, authenticate and initialize vlc Telnet session
     * 
     * @param server
     * @param port
     * @param password
     * @throws SocketException
     * @throws IOException
     */
    private void connect(String server, Integer port, String password)
            throws SocketException, IOException, VideoRecorderConnectionException {
        LOGGER.info("[VLC][Telnet Connect][" + server + "][" + port + "]");
        // Connect to the specified server
        telnet.connect(server, port);

        // Get input and output stream references
        in = telnet.getInputStream();
        out = new PrintStream(telnet.getOutputStream());

        readUntil("Password: ");
        write(password);

        // Advance to a prompt
        readUntil(prompt + " ");
    }

    /**
     * 
     * Reads Telnet response.
     * 
     * @param pattern
     * @return
     */
    private String readUntil(String pattern) {
        try {
            char lastChar = pattern.charAt(pattern.length() - 1);
            StringBuffer sb = new StringBuffer();
            char ch = (char) in.read();
            while (true) {
                sb.append(ch);
                if (ch == lastChar) {
                    if (sb.toString().endsWith(pattern)) {
                        LOGGER.info("[VLC][Telnet Response][" + sb + "]");

                        return sb.toString();
                    }
                }
                ch = (char) in.read();
            }
        } catch (Exception e) {
            LOGGER.info("[VLC][Telnet Error][" + e.getMessage() + "]");
        }
        return null;
    }

    /**
     * Sends actual Telnet command.
     * 
     * @param value
     */
    private void write(String value) throws VideoRecorderConnectionException {
        try {
            if (null == out) {
                throw new VideoRecorderConnectionException(
                        "No OutputStream(PrintStream) found to send Telent command.");
            }

            LOGGER.info("[VLC][Telnet Command][" + value + "]");

            out.println(value);
            out.flush();
        } catch (Exception e) {
            LOGGER.info("[VLC][Telnet Error][" + e.getMessage() + "]");
        }
    }

    /**
     * Sends a Telnet command and return the response.
     * 
     * @param command
     * @return
     */
    private String sendCommand(String command) {
        try {
            write(command);
            return readUntil(prompt + " ");
        } catch (Exception e) {
            LOGGER.info("[VLC][Telnet Error][" + e.getMessage() + "]");
        }
        return null;
    }

    /**
     * Close Telnet session.
     */
    private void disconnect() {
        try {
            telnet.disconnect();
        } catch (Exception e) {
            LOGGER.info("[VLC][Telnet Error][" + e.getMessage() + "]");
        }
    }

    public synchronized boolean shutDownVlc(int port) throws VideoRecorderConnectionException {
        LOGGER.info("[VLC][Telnet] Shutdown request received for port [" + port + "]");

        if ((null == telnetPassword) || (telnetPassword.isEmpty()) || (null == telnetHost)
                || (telnetHost.isEmpty())) {
            throw new VideoRecorderConnectionException(
                    "Cannt connect to Telnet interface of VLC with [" + telnetHost + "][" + port
                            + "]. Make sure Telnet host and Telnet password are not null or empty");
        }

        boolean isStopped = false;

        try {
            connect(telnetHost, port, telnetPassword);
            String output = sendCommand("shutdown");

            // String expected = "Shutting down.Bye-bye!>";
            String expected = "bye";

            output = output.replace("\n", "").replace("\r", "").trim();

            /*
             * if ( expected.equalsIgnoreCase( output ) ) { isStopped = true; }
             */

            if (output.toLowerCase().indexOf(expected.toLowerCase()) >= 0) {
                isStopped = true;
            }

            disconnect();

        } catch (IOException ioException) {
            throw new VideoRecorderConnectionException(
                    "An ioException happened while communicating with Telnet interface of VLC. [" + telnetHost
                            + "][" + port + "]" + ioException.getMessage());
        }

        return isStopped;

    }
}