com.dreamworks.dsp.server.EmbeddedSftpServer.java Source code

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Here is the source code for com.dreamworks.dsp.server.EmbeddedSftpServer.java

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package com.dreamworks.dsp.server;/*
                                   * Copyright 2014 the original author or
                                   * authors.
                                   * 
                                   * 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.
                                   */

import java.io.IOException;
import java.io.InputStream;
import java.math.BigInteger;
import java.nio.ByteBuffer;
import java.security.KeyFactory;
import java.security.PublicKey;
import java.security.spec.RSAPublicKeySpec;
import java.util.Collections;

import org.apache.sshd.SshServer;
import org.apache.sshd.common.NamedFactory;
import org.apache.sshd.common.file.FileSystemView;
import org.apache.sshd.common.file.nativefs.NativeFileSystemFactory;
import org.apache.sshd.common.file.nativefs.NativeFileSystemView;
import org.apache.sshd.common.util.Base64;
import org.apache.sshd.server.Command;
import org.apache.sshd.server.PublickeyAuthenticator;
import org.apache.sshd.server.keyprovider.SimpleGeneratorHostKeyProvider;
import org.apache.sshd.server.session.ServerSession;
import org.apache.sshd.server.sftp.SftpSubsystem;
import org.springframework.beans.factory.InitializingBean;
import org.springframework.context.SmartLifecycle;
import org.springframework.core.io.ClassPathResource;
import org.springframework.core.io.FileSystemResource;
import org.springframework.util.SocketUtils;
import org.springframework.util.StreamUtils;

/**
 * @author Artem Bilan
 */
public class EmbeddedSftpServer implements InitializingBean, SmartLifecycle {

    public static final int PORT = SocketUtils.findAvailableTcpPort();

    private final SshServer server = SshServer.setUpDefaultServer();

    private volatile int port;

    private volatile boolean running;

    public void setPort(int port) {
        this.port = port;
    }

    @Override
    public void afterPropertiesSet() throws Exception {
        final PublicKey allowedKey = decodePublicKey();
        this.server.setPublickeyAuthenticator(new PublickeyAuthenticator() {

            @Override
            public boolean authenticate(String username, PublicKey key, ServerSession session) {
                return key.equals(allowedKey);
            }

        });
        this.server.setPort(this.port);
        this.server.setKeyPairProvider(new SimpleGeneratorHostKeyProvider("hostkey.ser"));
        this.server.setSubsystemFactories(
                Collections.<NamedFactory<Command>>singletonList(new SftpSubsystem.Factory()));
        final String virtualDir = new FileSystemResource("").getFile().getAbsolutePath();
        this.server.setFileSystemFactory(new NativeFileSystemFactory() {

            @Override
            public FileSystemView createFileSystemView(org.apache.sshd.common.Session session) {
                return new NativeFileSystemView(session.getUsername(), false) {

                    @Override
                    public String getVirtualUserDir() {
                        return virtualDir;
                    }
                };
            }

        });
    }

    private PublicKey decodePublicKey() throws Exception {
        InputStream stream = new ClassPathResource("keys/sftp_rsa.pub").getInputStream();
        byte[] decodeBuffer = Base64.decodeBase64(StreamUtils.copyToByteArray(stream));
        ByteBuffer bb = ByteBuffer.wrap(decodeBuffer);
        int len = bb.getInt();
        byte[] type = new byte[len];
        bb.get(type);
        if ("ssh-rsa".equals(new String(type))) {
            BigInteger e = decodeBigInt(bb);
            BigInteger m = decodeBigInt(bb);
            RSAPublicKeySpec spec = new RSAPublicKeySpec(m, e);
            return KeyFactory.getInstance("RSA").generatePublic(spec);

        } else {
            throw new IllegalArgumentException("Only supports RSA");
        }
    }

    private BigInteger decodeBigInt(ByteBuffer bb) {
        int len = bb.getInt();
        byte[] bytes = new byte[len];
        bb.get(bytes);
        return new BigInteger(bytes);
    }

    @Override
    public boolean isAutoStartup() {
        return PORT == this.port;
    }

    @Override
    public int getPhase() {
        return Integer.MAX_VALUE;
    }

    @Override
    public void start() {
        try {
            server.start();
            this.running = true;
        } catch (IOException e) {
            throw new IllegalStateException(e);
        }
    }

    @Override
    public void stop(Runnable callback) {
        stop();
        callback.run();
    }

    @Override
    public void stop() {
        if (this.running) {
            try {
                server.stop(true);
            } catch (InterruptedException e) {
                throw new IllegalStateException(e);
            } finally {
                this.running = false;
            }
        }
    }

    @Override
    public boolean isRunning() {
        return this.running;
    }

}