imapplugin.java

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//
// This file is part of the OpenNMS(R) Application.
//
// OpenNMS(R) is Copyright (C) 2002-2003 The OpenNMS Group, Inc. All rights reserved.
// OpenNMS(R) is a derivative work, containing both original code, included code and modified
// code that was published under the GNU General Public License. Copyrights for modified
// and included code are below.
//
// OpenNMS(R) is a registered trademark of The OpenNMS Group, Inc.
//
// Modifications:
//
// 2004 Apr 30: Extended AbstractTcpPlugin and moved connection code up.
// 2003 Jul 21: Explicitly close sockets.
// 2003 Jul 18: Fixed exception to enable retries.
// 2003 Jan 31: Cleaned up some unused imports.
// 2003 Jan 29: Added response time
// 2002 Nov 14: Used non-blocking I/O for speed improvements.
//
// Original code base Copyright (C) 1999-2001 Oculan Corp. All rights reserved.
//
// This program 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 2 of the License, or
// (at your option) any later version.
//
// This program 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 this program; if not, write to the Free Software
// Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
//       
// For more information contact:
//      OpenNMS Licensing <[e-mail]>
//      http://www.opennms.org/
//      http://www.opennms.com/
//
// Tab Size = 8
//

package org.opennms.netmgt.capsd;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.net.Socket;

/**
 * <P>
 * This class is designed to be used by the capabilities daemon to test for the
 * existance of an IMAP server on remote interfaces. The class implements the
 * Plugin interface that allows it to be used along with other plugins by the
 * daemon.
 * </P>
 * 
 * @author <A HREF="mailto:[e-mail]">Sowmya Nataraj </A>
 * @author <a href="mailto:[e-mail]">Weave </a>
 * @author <A HREF="http://www.opennsm.org">OpenNMS </A>
 * 
 */
public final class ImapPlugin extends AbstractTcpPlugin {

    /**
     * <P>
     * The default port on which the host is checked to see if it supports IMAP.
     * </P>
     */
    private static final int DEFAULT_PORT = 143;

    /**
     * Default number of retries for IMAP requests
     */
    private final static int DEFAULT_RETRY = 0;

    /**
     * Default timeout (in milliseconds) for IMAP requests
     */
    private final static int DEFAULT_TIMEOUT = 5000; // in milliseconds

    /**
     * The BYE response received from the server in response to the logout
     */
    private static String IMAP_BYE_RESPONSE_PREFIX = "* BYE ";

    /**
     * The LOGOUT request sent to the server to close the connection
     */
    private static String IMAP_LOGOUT_REQUEST = "ONMSCAPSD LOGOUT\r\n";

    /**
     * The LOGOUT response received from the server in response to the logout
     */
    private static String IMAP_LOGOUT_RESPONSE_PREFIX = "ONMSCAPSD OK ";

    /**
     * The start of the initial banner received from the server
     */
    private static String IMAP_START_RESPONSE_PREFIX = "* OK ";

    /**
     * The name of the protocol supported by this plugin.
     */
    private static final String PROTOCOL_NAME = "IMAP";

    /**
     * @param protocol
     * @param defaultPort
     * @param defaultTimeout
     * @param defaultRetry
     */
    public ImapPlugin() {
        super(PROTOCOL_NAME, DEFAULT_PORT, DEFAULT_TIMEOUT, DEFAULT_RETRY);
    }

    /**
     * @param isAServer
     * @param socket
     * @return
     * @throws IOException
     */
    protected boolean checkProtocol(Socket socket, ConnectionConfig config) throws IOException {

        boolean isAServer = false;
        // Allocate a line reader
        //
        BufferedReader lineRdr = new BufferedReader(new InputStreamReader(socket.getInputStream()));

        //
        // Check the banner line for a valid return.
        //
        String banner = lineRdr.readLine();
        if (banner != null && banner.startsWith(IMAP_START_RESPONSE_PREFIX)) {
            //
            // Send the LOGOUT
            //
            socket.getOutputStream().write(IMAP_LOGOUT_REQUEST.getBytes());

            //
            // get the returned string, tokenize, and
            // verify the correct output.
            //
            String response = lineRdr.readLine();
            if (response != null && response.startsWith(IMAP_BYE_RESPONSE_PREFIX)) {
                response = lineRdr.readLine();
                if (response != null && response.startsWith(IMAP_LOGOUT_RESPONSE_PREFIX)) {
                    isAServer = true;
                }
            }
        }
        return isAServer;
    }
}