wagon-providers/wagon-ssh/src/main/java/org/apache/maven/wagon/providers/ssh/ScpWagon.java - maven-wagon - Git at Google

 package org.apache.maven.wagon.providers.ssh;

 /*
  * Copyright 2001-2004 The Apache Software Foundation.
  *
  * 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 com.jcraft.jsch.ChannelExec;
 import com.jcraft.jsch.JSch;
 import com.jcraft.jsch.Proxy;
 import com.jcraft.jsch.ProxyHTTP;
 import com.jcraft.jsch.ProxySOCKS5;
 import com.jcraft.jsch.Session;
 import com.jcraft.jsch.UserInfo;
 import org.apache.maven.wagon.AbstractWagon;
 import org.apache.maven.wagon.LazyFileOutputStream;
 import org.apache.maven.wagon.PathUtils;
 import org.apache.maven.wagon.ResourceDoesNotExistException;
 import org.apache.maven.wagon.TransferFailedException;
 import org.apache.maven.wagon.WagonConstants;
 import org.apache.maven.wagon.repository.RepositoryPermissions;
 import org.apache.maven.wagon.resource.Resource;
 import org.apache.maven.wagon.events.TransferEvent;
 import org.apache.maven.wagon.authentication.AuthenticationException;
 import org.apache.maven.wagon.authentication.AuthenticationInfo;
 import org.apache.maven.wagon.authorization.AuthorizationException;
 import org.apache.maven.wagon.proxy.ProxyInfo;
 import org.codehaus.plexus.util.StringUtils;

 import java.io.File;
 import java.io.IOException;
 import java.io.InputStream;
 import java.io.OutputStream;

 /**
  * A base class for deployers and fetchers using protocols from SSH2 family and
  * JSch library for underlining implmenetation
  * <p/>
  * This is responsible for authentification stage of the process.
  * <p/>
  * We will first try to use public keys for authentication and if that doesn't
  * work then we fall back to using the login and password
  *
  * @todo [BP] add compression flag
  *
  * @version $Id$
  */
 public class ScpWagon
         extends AbstractWagon implements SshCommandExecutor
 {
     public static String EXEC_CHANNEL = "exec";

     public static int DEFAULT_SSH_PORT = 22;

     public static int SOCKS5_PROXY_PORT = 1080;

     protected Session session = null;

     // ----------------------------------------------------------------------
     //
     // ----------------------------------------------------------------------

     public void openConnection()
             throws AuthenticationException
     {
         try
         {
             final AuthenticationInfo authInfo = getRepository().getAuthenticationInfo();

             if ( authInfo == null )
             {
                 throw new IllegalArgumentException( "Authentication Credentials cannot be null for SSH protocol" );
             }

             JSch jsch = new JSch();

             int port = getRepository().getPort();

             if ( port == WagonConstants.UNKNOWN_PORT )
             {
                 port = DEFAULT_SSH_PORT;
             }

             String host = getRepository().getHost();

             session = jsch.getSession( authInfo.getUserName(), host, port );

             // If user don't define a password, he want to use a private key
             if ( authInfo.getPassword() == null )
             {
                 File privateKey;

                 if ( authInfo.getPrivateKey() != null )
                 {
                     privateKey = new File( authInfo.getPrivateKey() );
                 }
                 else
                 {
                     privateKey = findPrivateKey();
                 }

                 if ( privateKey.exists() )
                 {
                     if ( authInfo.getPassphrase() == null )
                     {
                         authInfo.setPassphrase( "" );
                     }

                     fireSessionDebug( "Using private key: " + privateKey );

                     jsch.addIdentity( privateKey.getAbsolutePath(), authInfo.getPassphrase() );
                 }
                 else
                 {
                     String msg = "Private key was not found. You must define a private key or a password for repo: " + getRepository().getName();

                     throw new AuthenticationException( msg );
                 }
             }

             if ( proxyInfo != null && proxyInfo.getHost() != null )
             {
                 Proxy proxy;

                 int proxyPort = proxyInfo.getPort();

                 // HACK: if port == 1080 we will use SOCKS5 Proxy, otherwise will use HTTP Proxy
                 if ( proxyPort == SOCKS5_PROXY_PORT )
                 {
                     proxy = new ProxySOCKS5( proxyInfo.getHost() );
                     ( ( ProxySOCKS5 ) proxy ).setUserPasswd( proxyInfo.getUserName(),
                             proxyInfo.getPassword() );
                 }
                 else
                 {
                     proxy = new ProxyHTTP( proxyInfo.getHost(), proxyPort );
                     ( ( ProxyHTTP ) proxy ).setUserPasswd( proxyInfo.getUserName(),
                             proxyInfo.getPassword() );
                 }

                 proxy.connect( session, host, port );
             }

             // username and password will be given via UserInfo interface.
             UserInfo ui = new WagonUserInfo( authInfo );

             session.setUserInfo( ui );

             session.connect();
         }
         catch ( Exception e )
         {
             fireSessionError( e );

             throw new AuthenticationException( "Cannot connect. Reason: " + e.getMessage(), e );
         }
     }

     // ----------------------------------------------------------------------
     //
     // ----------------------------------------------------------------------

     private File findPrivateKey()
     {
         String privateKeyDirectory = System.getProperty( "wagon.privateKeyDirectory" );

         if ( privateKeyDirectory == null )
         {
             privateKeyDirectory = System.getProperty( "user.home" );
         }

         File privateKey = new File( privateKeyDirectory, ".ssh/id_dsa" );

         if ( !privateKey.exists() )
         {
             privateKey = new File( privateKeyDirectory, ".ssh/id_rsa" );
         }

         return privateKey;
     }

     // ----------------------------------------------------------------------
     //
     // ----------------------------------------------------------------------

     public void closeConnection()
     {
         if ( session != null )
         {
             session.disconnect();
         }
     }

     public void executeCommand( String command )
             throws TransferFailedException
     {
         ChannelExec channel = null;

         try
         {
             fireTransferDebug( "Executing command: " + command );

             channel = ( ChannelExec ) session.openChannel( EXEC_CHANNEL );

             channel.setCommand( command );

             channel.connect();
         }
         catch ( Exception e )
         {
             throw new TransferFailedException( "Cannot execute remote command: " + command, e );
         }
         finally
         {
             if ( channel != null )
             {
                 channel.disconnect();
             }
         }
     }

     public void put( File source, String resourceName )
             throws TransferFailedException, ResourceDoesNotExistException, AuthorizationException
     {

         String basedir = getRepository().getBasedir();

         resourceName = StringUtils.replace(resourceName, "\\", "/");
         String dir = PathUtils.dirname( resourceName  );
         dir = StringUtils.replace(dir, "\\", "/");

         String mkdirCmd = "mkdir -p " + basedir + "/"  + dir  + "\n";

         executeCommand( mkdirCmd );

         ChannelExec channel = null;

         //I/O streams for remote scp
         OutputStream out = null;

         InputStream in;

         try
         {
             // exec 'scp -t rfile' remotely
             String command = "scp -t " + basedir + "/"  + resourceName;

             fireTransferDebug( "Executing command: " + command );

             channel = ( ChannelExec ) session.openChannel( EXEC_CHANNEL );

             channel.setCommand( command );

             // get I/O streams for remote scp
             out = channel.getOutputStream();

             in = channel.getInputStream();

             channel.connect();

             byte[] tmp = new byte[ 1 ];

             if ( checkAck( in ) != 0 )
             {
                 throw new TransferFailedException( "ACK check failed" );
             }

             // send "C0644 filesize filename", where filename should not include '/'
             long filesize = source.length();

             command = "C0644 " + filesize + " ";

             if( resourceName.lastIndexOf( '/' ) > 0 )
             {
                 command += resourceName.substring( resourceName.lastIndexOf( '/' ) + 1 );
             }
             else
             {
                 command+=resourceName;
             }

             command += "\n";

             out.write( command.getBytes() );

             out.flush();

             if ( checkAck( in ) != 0 )
             {
                 throw new TransferFailedException( "ACK check failed" );
             }


             Resource resource = new Resource( resourceName );

             putTransfer( resource, source, out, false );

             byte[] buf = new byte[ 1024 ];

             // send '\0'
             buf[ 0 ] = 0;

             out.write( buf, 0, 1 );

             out.flush();

             if ( checkAck( in ) != 0 )
             {
                 throw new TransferFailedException( "ACK check failed" );
             }
         }
         catch ( Exception e )
         {
             String msg = "Error occured while deploying '" + resourceName + "' to remote repository: " + getRepository().getUrl();

             throw new TransferFailedException( msg, e );
         }

         RepositoryPermissions permissions = getRepository().getPermissions();

         if ( permissions != null && permissions.getGroup() != null )
         {
             executeCommand( "chgrp " + permissions.getGroup() + " " + basedir + "/" + resourceName + "\n" );
         }

         if ( permissions != null && permissions.getFileMode() != null )
         {
             executeCommand( "chmod " + permissions.getFileMode() + " " + basedir + "/" + resourceName + "\n" );
         }

         if ( channel != null )
         {
             shutdownStream( out );

             channel.disconnect();
         }
     }

     public void get( String resourceName, File destination )
             throws TransferFailedException, ResourceDoesNotExistException, AuthorizationException
     {
         ChannelExec channel = null;

         //I/O streams for remote scp
         OutputStream out = null;

         InputStream in = null;

         createParentDirectories( destination );

         LazyFileOutputStream outputStream = new LazyFileOutputStream( destination );

         String basedir = getRepository().getBasedir();

         //@todo get content lenght and last modified
         Resource resource = new Resource( resourceName );


         try
         {
             String cmd = "scp -f " + basedir + "/" + resourceName;

             fireTransferDebug( "Executing command: " + cmd );

             channel = ( ChannelExec ) session.openChannel( EXEC_CHANNEL );

             channel.setCommand( cmd );

             // get I/O streams for remote scp
             out = channel.getOutputStream();

             in = channel.getInputStream();

             channel.connect();

             byte[] buf = new byte[ 1024 ];

             // send '\0'
             buf[ 0 ] = 0;

             out.write( buf, 0, 1 );

             out.flush();

             while ( true )
             {
                 // TODO: is this really an ACK, or just an in.read()? If the latter, change checkAck method to not return a value, but throw an exception on non-zero result
                 int c = checkAck( in );

                 if ( c != 'C' )
                 {
                     break;
                 }

                 // read '0644 '
                 in.read( buf, 0, 5 );

                 int filesize = 0;

                 // get file size
                 while ( true )
                 {
                     in.read( buf, 0, 1 );

                     if ( buf[ 0 ] == ' ' )
                     {
                         break;
                     }

                     filesize = filesize * 10 + ( buf[ 0 ] - '0' );
                 }

                 resource.setContentLength(  filesize );


                 for ( int i = 0; ; i++ )
                 {
                     in.read( buf, i, 1 );

                     if ( buf[ i ] == ( byte ) 0x0a )
                     {
                         break;
                     }
                 }

                 // send '\0'
                 buf[ 0 ] = 0;

                 out.write( buf, 0, 1 );

                 out.flush();

                 fireGetStarted( resource, destination );

                 TransferEvent transferEvent = new TransferEvent( this, resource, TransferEvent.TRANSFER_PROGRESS, TransferEvent.REQUEST_GET );

                 try
                 {
                     while ( true )
                     {
                         int len = Math.min( buf.length, filesize );

                         in.read( buf, 0, len );

                         outputStream.write( buf, 0, len );

                         fireTransferProgress( transferEvent, buf, len );

                         filesize -= len;

                         if ( filesize == 0 )
                         {
                             break;
                         }
                     }
                 }
                 catch ( IOException e )
                 {
                     fireTransferError( resource, e );

                     shutdownStream( outputStream );

                     if ( destination.exists() )
                     {
                         boolean deleted = destination.delete();

                         if ( !deleted )
                         {
                             destination.deleteOnExit();
                         }
                     }

                     String msg = "GET request of: " + resource + " from " + repository.getName() + "failed";

                     throw new TransferFailedException( msg, e );

                 }

                 fireGetCompleted( resource, destination );

                 if ( checkAck( in ) != 0 )
                 {
                     throw new TransferFailedException( "Wrong ACK" );
                 }
                 else
                 {
                     fireTransferDebug( "ACK check: OK" );
                 }

                 // send '\0'
                 buf[ 0 ] = 0;

                 out.write( buf, 0, 1 );

                 out.flush();
             }
         }
         catch ( Exception e )
         {
             fireTransferError( resource, e );

             if ( destination.exists() )
             {
                 boolean deleted = destination.delete();

                 if ( !deleted )
                 {
                     destination.deleteOnExit();
                 }
             }

             String msg = "Error occured while deploying to remote repository:" + getRepository();

             throw new TransferFailedException( msg, e );
         }
         finally
         {
             if ( out != null )
             {
                 shutdownStream( out );
             }
             if ( channel != null )
             {
                 channel.disconnect();
             }

             shutdownStream( outputStream );
         }
     }

     public boolean getIfNewer( String resourceName, File destination, long timestamp )
     {
         throw new UnsupportedOperationException( "getIfNewer is scp wagon must be still implemented" );
     }

 // ----------------------------------------------------------------------
 // JSch user info
 // ----------------------------------------------------------------------
 // TODO: are the prompt values really right? Is there an alternative to UserInfo?
     public static class WagonUserInfo
             implements UserInfo
     {
         AuthenticationInfo authInfo;

         WagonUserInfo( AuthenticationInfo authInfo )
         {
             this.authInfo = authInfo;
         }

         public String getPassphrase()
         {
             return authInfo.getPassphrase();
         }

         public String getPassword()
         {
             return authInfo.getPassword();
         }

         public boolean promptPassphrase( String arg0 )
         {
             return true;
         }

         public boolean promptPassword( String arg0 )
         {
             return true;
         }

         public boolean promptYesNo( String arg0 )
         {
             return true;
         }

         public void showMessage( String message )
         {
             // TODO: is this really debug?
             //fireTransferDebug( message );
         }
     }

     static int checkAck( InputStream in ) throws IOException
     {
         int b = in.read();
         // b may be 0 for success,
         //          1 for error,
         //          2 for fatal error,
         //         -1

         if ( b == 0 || b == -1 )
         {
             return b;
         }

         if ( b == 1 || b == 2 )
         {
             StringBuffer sb = new StringBuffer();

             int c;

             do
             {
                 c = in.read();

                 sb.append( ( char ) c );
             }
             while ( c != '\n' );

             if ( b == 1 )
             {
                 // TODO: log (throw exception?)
                 // error
                 System.out.print( sb.toString() );
             }
             if ( b == 2 )
             {
                 // TODO: throw exception
                 // fatal error
                 System.out.print( sb.toString() );
             }
         }

         return b;
     }
 }
	package org.apache.maven.wagon.providers.ssh;

	/*
	* Copyright 2001-2004 The Apache Software Foundation.
	*
	* 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 com.jcraft.jsch.ChannelExec;
	import com.jcraft.jsch.JSch;
	import com.jcraft.jsch.Proxy;
	import com.jcraft.jsch.ProxyHTTP;
	import com.jcraft.jsch.ProxySOCKS5;
	import com.jcraft.jsch.Session;
	import com.jcraft.jsch.UserInfo;
	import org.apache.maven.wagon.AbstractWagon;
	import org.apache.maven.wagon.LazyFileOutputStream;
	import org.apache.maven.wagon.PathUtils;
	import org.apache.maven.wagon.ResourceDoesNotExistException;
	import org.apache.maven.wagon.TransferFailedException;
	import org.apache.maven.wagon.WagonConstants;
	import org.apache.maven.wagon.repository.RepositoryPermissions;
	import org.apache.maven.wagon.resource.Resource;
	import org.apache.maven.wagon.events.TransferEvent;
	import org.apache.maven.wagon.authentication.AuthenticationException;
	import org.apache.maven.wagon.authentication.AuthenticationInfo;
	import org.apache.maven.wagon.authorization.AuthorizationException;
	import org.apache.maven.wagon.proxy.ProxyInfo;
	import org.codehaus.plexus.util.StringUtils;

	import java.io.File;
	import java.io.IOException;
	import java.io.InputStream;
	import java.io.OutputStream;

	/**
	* A base class for deployers and fetchers using protocols from SSH2 family and
	* JSch library for underlining implmenetation
	* <p/>
	* This is responsible for authentification stage of the process.
	* <p/>
	* We will first try to use public keys for authentication and if that doesn't
	* work then we fall back to using the login and password
	*
	* @todo [BP] add compression flag
	*
	* @version $Id$
	*/
	public class ScpWagon
	extends AbstractWagon implements SshCommandExecutor
	{
	public static String EXEC_CHANNEL = "exec";

	public static int DEFAULT_SSH_PORT = 22;

	public static int SOCKS5_PROXY_PORT = 1080;

	protected Session session = null;

	// ----------------------------------------------------------------------
	//
	// ----------------------------------------------------------------------

	public void openConnection()
	throws AuthenticationException
	{
	try
	{
	final AuthenticationInfo authInfo = getRepository().getAuthenticationInfo();

	if ( authInfo == null )
	{
	throw new IllegalArgumentException( "Authentication Credentials cannot be null for SSH protocol" );
	}

	JSch jsch = new JSch();

	int port = getRepository().getPort();

	if ( port == WagonConstants.UNKNOWN_PORT )
	{
	port = DEFAULT_SSH_PORT;
	}

	String host = getRepository().getHost();

	session = jsch.getSession( authInfo.getUserName(), host, port );

	// If user don't define a password, he want to use a private key
	if ( authInfo.getPassword() == null )
	{
	File privateKey;

	if ( authInfo.getPrivateKey() != null )
	{
	privateKey = new File( authInfo.getPrivateKey() );
	}
	else
	{
	privateKey = findPrivateKey();
	}

	if ( privateKey.exists() )
	{
	if ( authInfo.getPassphrase() == null )
	{
	authInfo.setPassphrase( "" );
	}

	fireSessionDebug( "Using private key: " + privateKey );

	jsch.addIdentity( privateKey.getAbsolutePath(), authInfo.getPassphrase() );
	}
	else
	{
	String msg = "Private key was not found. You must define a private key or a password for repo: " + getRepository().getName();

	throw new AuthenticationException( msg );
	}
	}

	if ( proxyInfo != null && proxyInfo.getHost() != null )
	{
	Proxy proxy;

	int proxyPort = proxyInfo.getPort();

	// HACK: if port == 1080 we will use SOCKS5 Proxy, otherwise will use HTTP Proxy
	if ( proxyPort == SOCKS5_PROXY_PORT )
	{
	proxy = new ProxySOCKS5( proxyInfo.getHost() );
	( ( ProxySOCKS5 ) proxy ).setUserPasswd( proxyInfo.getUserName(),
	proxyInfo.getPassword() );
	}
	else
	{
	proxy = new ProxyHTTP( proxyInfo.getHost(), proxyPort );
	( ( ProxyHTTP ) proxy ).setUserPasswd( proxyInfo.getUserName(),
	proxyInfo.getPassword() );
	}

	proxy.connect( session, host, port );
	}

	// username and password will be given via UserInfo interface.
	UserInfo ui = new WagonUserInfo( authInfo );

	session.setUserInfo( ui );

	session.connect();
	}
	catch ( Exception e )
	{
	fireSessionError( e );

	throw new AuthenticationException( "Cannot connect. Reason: " + e.getMessage(), e );
	}
	}

	// ----------------------------------------------------------------------
	//
	// ----------------------------------------------------------------------

	private File findPrivateKey()
	{
	String privateKeyDirectory = System.getProperty( "wagon.privateKeyDirectory" );

	if ( privateKeyDirectory == null )
	{
	privateKeyDirectory = System.getProperty( "user.home" );
	}

	File privateKey = new File( privateKeyDirectory, ".ssh/id_dsa" );

	if ( !privateKey.exists() )
	{
	privateKey = new File( privateKeyDirectory, ".ssh/id_rsa" );
	}

	return privateKey;
	}

	// ----------------------------------------------------------------------
	//
	// ----------------------------------------------------------------------

	public void closeConnection()
	{
	if ( session != null )
	{
	session.disconnect();
	}
	}

	public void executeCommand( String command )
	throws TransferFailedException
	{
	ChannelExec channel = null;

	try
	{
	fireTransferDebug( "Executing command: " + command );

	channel = ( ChannelExec ) session.openChannel( EXEC_CHANNEL );

	channel.setCommand( command );

	channel.connect();
	}
	catch ( Exception e )
	{
	throw new TransferFailedException( "Cannot execute remote command: " + command, e );
	}
	finally
	{
	if ( channel != null )
	{
	channel.disconnect();
	}
	}
	}

	public void put( File source, String resourceName )
	throws TransferFailedException, ResourceDoesNotExistException, AuthorizationException
	{

	String basedir = getRepository().getBasedir();

	resourceName = StringUtils.replace(resourceName, "\\", "/");
	String dir = PathUtils.dirname( resourceName );
	dir = StringUtils.replace(dir, "\\", "/");

	String mkdirCmd = "mkdir -p " + basedir + "/" + dir + "\n";

	executeCommand( mkdirCmd );

	ChannelExec channel = null;

	//I/O streams for remote scp
	OutputStream out = null;

	InputStream in;

	try
	{
	// exec 'scp -t rfile' remotely
	String command = "scp -t " + basedir + "/" + resourceName;

	fireTransferDebug( "Executing command: " + command );

	channel = ( ChannelExec ) session.openChannel( EXEC_CHANNEL );

	channel.setCommand( command );

	// get I/O streams for remote scp
	out = channel.getOutputStream();

	in = channel.getInputStream();

	channel.connect();

	byte[] tmp = new byte[ 1 ];

	if ( checkAck( in ) != 0 )
	{
	throw new TransferFailedException( "ACK check failed" );
	}

	// send "C0644 filesize filename", where filename should not include '/'
	long filesize = source.length();

	command = "C0644 " + filesize + " ";

	if( resourceName.lastIndexOf( '/' ) > 0 )
	{
	command += resourceName.substring( resourceName.lastIndexOf( '/' ) + 1 );
	}
	else
	{
	command+=resourceName;
	}

	command += "\n";

	out.write( command.getBytes() );

	out.flush();

	if ( checkAck( in ) != 0 )
	{
	throw new TransferFailedException( "ACK check failed" );
	}


	Resource resource = new Resource( resourceName );

	putTransfer( resource, source, out, false );

	byte[] buf = new byte[ 1024 ];

	// send '\0'
	buf[ 0 ] = 0;

	out.write( buf, 0, 1 );

	out.flush();

	if ( checkAck( in ) != 0 )
	{
	throw new TransferFailedException( "ACK check failed" );
	}
	}
	catch ( Exception e )
	{
	String msg = "Error occured while deploying '" + resourceName + "' to remote repository: " + getRepository().getUrl();

	throw new TransferFailedException( msg, e );
	}

	RepositoryPermissions permissions = getRepository().getPermissions();

	if ( permissions != null && permissions.getGroup() != null )
	{
	executeCommand( "chgrp " + permissions.getGroup() + " " + basedir + "/" + resourceName + "\n" );
	}

	if ( permissions != null && permissions.getFileMode() != null )
	{
	executeCommand( "chmod " + permissions.getFileMode() + " " + basedir + "/" + resourceName + "\n" );
	}

	if ( channel != null )
	{
	shutdownStream( out );

	channel.disconnect();
	}
	}

	public void get( String resourceName, File destination )
	throws TransferFailedException, ResourceDoesNotExistException, AuthorizationException
	{
	ChannelExec channel = null;

	//I/O streams for remote scp
	OutputStream out = null;

	InputStream in = null;

	createParentDirectories( destination );

	LazyFileOutputStream outputStream = new LazyFileOutputStream( destination );

	String basedir = getRepository().getBasedir();

	//@todo get content lenght and last modified
	Resource resource = new Resource( resourceName );


	try
	{
	String cmd = "scp -f " + basedir + "/" + resourceName;

	fireTransferDebug( "Executing command: " + cmd );

	channel = ( ChannelExec ) session.openChannel( EXEC_CHANNEL );

	channel.setCommand( cmd );

	// get I/O streams for remote scp
	out = channel.getOutputStream();

	in = channel.getInputStream();

	channel.connect();

	byte[] buf = new byte[ 1024 ];

	// send '\0'
	buf[ 0 ] = 0;

	out.write( buf, 0, 1 );

	out.flush();

	while ( true )
	{
	// TODO: is this really an ACK, or just an in.read()? If the latter, change checkAck method to not return a value, but throw an exception on non-zero result
	int c = checkAck( in );

	if ( c != 'C' )
	{
	break;
	}

	// read '0644 '
	in.read( buf, 0, 5 );

	int filesize = 0;

	// get file size
	while ( true )
	{
	in.read( buf, 0, 1 );

	if ( buf[ 0 ] == ' ' )
	{
	break;
	}

	filesize = filesize * 10 + ( buf[ 0 ] - '0' );
	}

	resource.setContentLength( filesize );


	for ( int i = 0; ; i++ )
	{
	in.read( buf, i, 1 );

	if ( buf[ i ] == ( byte ) 0x0a )
	{
	break;
	}
	}

	// send '\0'
	buf[ 0 ] = 0;

	out.write( buf, 0, 1 );

	out.flush();

	fireGetStarted( resource, destination );

	TransferEvent transferEvent = new TransferEvent( this, resource, TransferEvent.TRANSFER_PROGRESS, TransferEvent.REQUEST_GET );

	try
	{
	while ( true )
	{
	int len = Math.min( buf.length, filesize );

	in.read( buf, 0, len );

	outputStream.write( buf, 0, len );

	fireTransferProgress( transferEvent, buf, len );

	filesize -= len;

	if ( filesize == 0 )
	{
	break;
	}
	}
	}
	catch ( IOException e )
	{
	fireTransferError( resource, e );

	shutdownStream( outputStream );

	if ( destination.exists() )
	{
	boolean deleted = destination.delete();

	if ( !deleted )
	{
	destination.deleteOnExit();
	}
	}

	String msg = "GET request of: " + resource + " from " + repository.getName() + "failed";

	throw new TransferFailedException( msg, e );

	}

	fireGetCompleted( resource, destination );

	if ( checkAck( in ) != 0 )
	{
	throw new TransferFailedException( "Wrong ACK" );
	}
	else
	{
	fireTransferDebug( "ACK check: OK" );
	}

	// send '\0'
	buf[ 0 ] = 0;

	out.write( buf, 0, 1 );

	out.flush();
	}
	}
	catch ( Exception e )
	{
	fireTransferError( resource, e );

	if ( destination.exists() )
	{
	boolean deleted = destination.delete();

	if ( !deleted )
	{
	destination.deleteOnExit();
	}
	}

	String msg = "Error occured while deploying to remote repository:" + getRepository();

	throw new TransferFailedException( msg, e );
	}
	finally
	{
	if ( out != null )
	{
	shutdownStream( out );
	}
	if ( channel != null )
	{
	channel.disconnect();
	}

	shutdownStream( outputStream );
	}
	}

	public boolean getIfNewer( String resourceName, File destination, long timestamp )
	{
	throw new UnsupportedOperationException( "getIfNewer is scp wagon must be still implemented" );
	}

	// ----------------------------------------------------------------------
	// JSch user info
	// ----------------------------------------------------------------------
	// TODO: are the prompt values really right? Is there an alternative to UserInfo?
	public static class WagonUserInfo
	implements UserInfo
	{
	AuthenticationInfo authInfo;

	WagonUserInfo( AuthenticationInfo authInfo )
	{
	this.authInfo = authInfo;
	}

	public String getPassphrase()
	{
	return authInfo.getPassphrase();
	}

	public String getPassword()
	{
	return authInfo.getPassword();
	}

	public boolean promptPassphrase( String arg0 )
	{
	return true;
	}

	public boolean promptPassword( String arg0 )
	{
	return true;
	}

	public boolean promptYesNo( String arg0 )
	{
	return true;
	}

	public void showMessage( String message )
	{
	// TODO: is this really debug?
	//fireTransferDebug( message );
	}
	}

	static int checkAck( InputStream in ) throws IOException
	{
	int b = in.read();
	// b may be 0 for success,
	// 1 for error,
	// 2 for fatal error,
	// -1

	if ( b == 0 \|\| b == -1 )
	{
	return b;
	}

	if ( b == 1 \|\| b == 2 )
	{
	StringBuffer sb = new StringBuffer();

	int c;

	do
	{
	c = in.read();

	sb.append( ( char ) c );
	}
	while ( c != '\n' );

	if ( b == 1 )
	{
	// TODO: log (throw exception?)
	// error
	System.out.print( sb.toString() );
	}
	if ( b == 2 )
	{
	// TODO: throw exception
	// fatal error
	System.out.print( sb.toString() );
	}
	}

	return b;
	}
	}