SFTPServer.java

/*
*Copyright (c) 2014, WSO2 Inc. (http://www.wso2.org) All Rights Reserved.
*
*WSO2 Inc. licenses this file to you 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 org.wso2.carbon.automation.extensions.servers.sftpserver;

import org.apache.commons.lang3.StringUtils;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.sshd.SshServer;
import org.apache.sshd.common.NamedFactory;
import org.apache.sshd.server.Command;
import org.apache.sshd.server.PasswordAuthenticator;
import org.apache.sshd.server.command.ScpCommandFactory;
import org.apache.sshd.server.keyprovider.SimpleGeneratorHostKeyProvider;
import org.apache.sshd.server.session.ServerSession;
import org.apache.sshd.server.sftp.SftpSubsystem;

import java.io.IOException;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;

/**
 * This class starts a SFTP Server instance which provides a secured backend for file transfer operations
 */
public class SFTPServer extends Thread {

    private Log log = LogFactory.getLog(SFTPServer.class);

    private static final String USERNAME = "SFTPUser";

    private static final char[] PASSWORD = {'S', 'F', 'T', 'P', '3', '2', '1'};

    private static SshServer sshServer = SshServer.setUpDefaultServer();

    private static int port = 8005;

    private static boolean isKeepAlive = false;

    public boolean isKeepAlive() {
        return isKeepAlive;
    }

    public static void setKeepAlive(boolean keepAlive) {
        isKeepAlive = keepAlive;
    }

    public void startServer() {
        Thread thread = new Thread(new SFTPServer());
        thread.start();
    }

    public void run() {

        sshServer.setPort(port);
        sshServer.setSubsystemFactories(Arrays.<NamedFactory<Command>>asList(new SftpSubsystem.Factory()));
        sshServer.setCommandFactory(new ScpCommandFactory());
        sshServer.setKeyPairProvider(new SimpleGeneratorHostKeyProvider("hostkey.ser"));
        sshServer.setPasswordAuthenticator(new PasswordAuthenticator() {
            @Override
            public boolean authenticate(final String username, final String password,
                                        final ServerSession session) {
                return StringUtils.equals(username, USERNAME) && StringUtils.equals
                        (password, java.nio.CharBuffer.wrap(PASSWORD).toString());
            }
        });

        List<NamedFactory<Command>> namedFactoryList = new ArrayList<NamedFactory<Command>>();
        namedFactoryList.add(new SftpSubsystem.Factory());
        sshServer.setSubsystemFactories(namedFactoryList);

        try {
            sshServer.start();
        } catch (IOException e) {
            log.error("Exception occurred " + e);
        }
        log.info("SFTP Server Stared successfully on port " + port);

        while (isKeepAlive) {
            try {
                Thread.sleep(3000);
            } catch (InterruptedException e) {
                log.error("Exception occurred " + e);
            }
        }
    }

    public void stopServer() throws InterruptedException {
        sshServer.stop();
        log.info("SFTP Server Run On Port " + port + " Stopped successfully ..... ");
    }
}