ftp.java

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/*
 * Copyright 2001-2005 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.
 */
package org.apache.commons.net.ftp;
import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.OutputStreamWriter;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.net.InetAddress;
import java.net.Socket;
import java.net.SocketException;
import java.util.Enumeration;
import java.util.Vector;

import org.apache.commons.net.MalformedServerReplyException;
import org.apache.commons.net.ProtocolCommandListener;
import org.apache.commons.net.ProtocolCommandSupport;
import org.apache.commons.net.SocketClient;
import org.apache.commons.net.telnet.TelnetClient;

/***
 * FTP provides the basic the functionality necessary to implement your
 * own FTP client.  It extends org.apache.commons.net.TelnetClient
 * simply because it saves the writing of extra code to handle the FTP
 * control connection which always remains open during an FTP session and
 * uses the Telnet protocol.  Aggregation would require writing new
 * wrapper methods and wouldn't leverage the functionality already
 * present in org.apache.commons.net.SocketClient.
 * <p>
 * To derive the full benefits of the FTP class requires some knowledge
 * of the FTP protocol defined in RFC 959.  However, there is no reason
 * why you should have to use the FTP class.  The
 * {@link org.apache.commons.net.ftp.FTPClient} class,
 * derived from FTP,
 * implements all the functionality required of an FTP client.  The
 * FTP class is made public to provide access to various FTP constants
 * and to make it easier for adventurous programmers (or those with
 * special needs) to interact with the FTP protocol and implement their
 * own clients.  A set of methods with names corresponding to the FTP
 * command names are provided to facilitate this interaction.
 * <p>
 * You should keep in mind that the FTP server may choose to prematurely
 * close a connection if the client has been idle for longer than a
 * given time period (usually 900 seconds).  The FTP class will detect a
 * premature FTP server connection closing when it receives a
 * {@link org.apache.commons.net.ftp.FTPReply#SERVICE_NOT_AVAILABLE FTPReply.SERVICE_NOT_AVAILABLE }
 *  response to a command.
 * When that occurs, the FTP class method encountering that reply will throw
 * an {@link org.apache.commons.net.ftp.FTPConnectionClosedException}
 * .  <code>FTPConectionClosedException</code>
 * is a subclass of <code> IOException </code> and therefore need not be
 * caught separately, but if you are going to catch it separately, its
 * catch block must appear before the more general <code> IOException </code>
 * catch block.  When you encounter an
 * {@link org.apache.commons.net.ftp.FTPConnectionClosedException}
 * , you must disconnect the connection with
 * {@link #disconnect  disconnect() } to properly clean up the
 * system resources used by FTP.  Before disconnecting, you may check the
 * last reply code and text with
 * {@link #getReplyCode  getReplyCode },
 * {@link #getReplyString  getReplyString },
 * and {@link #getReplyStrings  getReplyStrings}.
 * You may avoid server disconnections while the client is idle by
 * periodicaly sending NOOP commands to the server.
 * <p>
 * Rather than list it separately for each method, we mention here that
 * every method communicating with the server and throwing an IOException
 * can also throw a
 * {@link org.apache.commons.net.MalformedServerReplyException}
 * , which is a subclass
 * of IOException.  A MalformedServerReplyException will be thrown when
 * the reply received from the server deviates enough from the protocol
 * specification that it cannot be interpreted in a useful manner despite
 * attempts to be as lenient as possible.
 * <p>
 * <p>
 * @author Daniel F. Savarese
 * @see FTPClient
 * @see FTPConnectionClosedException
 * @see org.apache.commons.net.MalformedServerReplyException
 ***/

public class FTP extends TelnetClient
{
    /*** The default FTP data port (20). ***/
    public static final int DEFAULT_DATA_PORT = 20;
    /*** The default FTP control port (21). ***/
    public static final int DEFAULT_PORT = 21;

    /***
     * A constant used to indicate the file(s) being transfered should
     * be treated as ASCII.  This is the default file type.  All constants
     * ending in <code>FILE_TYPE</code> are used to indicate file types.
     ***/
    public static final int ASCII_FILE_TYPE = 0;

    /***
     * A constant used to indicate the file(s) being transfered should
     * be treated as EBCDIC.  Note however that there are several different
     * EBCDIC formats.  All constants ending in <code>FILE_TYPE</code>
     * are used to indicate file types.
     ***/
    public static final int EBCDIC_FILE_TYPE = 1;

    /***
     * A constant used to indicate the file(s) being transfered should
     * be treated as a binary image, i.e., no translations should be
     * performed.  All constants ending in <code>FILE_TYPE</code> are used to
     * indicate file types.
     ***/
    public static final int IMAGE_FILE_TYPE = 2;

    /***
     * A constant used to indicate the file(s) being transfered should
     * be treated as a binary image, i.e., no translations should be
     * performed.  All constants ending in <code>FILE_TYPE</code> are used to
     * indicate file types.
     ***/
    public static final int BINARY_FILE_TYPE = 2;

    /***
     * A constant used to indicate the file(s) being transfered should
     * be treated as a local type.  All constants ending in
     * <code>FILE_TYPE</code> are used to indicate file types.
     ***/
    public static final int LOCAL_FILE_TYPE = 3;

    /***
     * A constant used for text files to indicate a non-print text format.
     * This is the default format.
     * All constants ending in <code>TEXT_FORMAT</code> are used to indicate
     * text formatting for text transfers (both ASCII and EBCDIC).
     ***/
    public static final int NON_PRINT_TEXT_FORMAT = 4;

    /***
     * A constant used to indicate a text file contains format vertical format
     * control characters.
     * All constants ending in <code>TEXT_FORMAT</code> are used to indicate
     * text formatting for text transfers (both ASCII and EBCDIC).
     ***/
    public static final int TELNET_TEXT_FORMAT = 5;

    /***
     * A constant used to indicate a text file contains ASA vertical format
     * control characters.
     * All constants ending in <code>TEXT_FORMAT</code> are used to indicate
     * text formatting for text transfers (both ASCII and EBCDIC).
     ***/
    public static final int CARRIAGE_CONTROL_TEXT_FORMAT = 6;

    /***
     * A constant used to indicate a file is to be treated as a continuous
     * sequence of bytes.  This is the default structure.  All constants ending
     * in <code>_STRUCTURE</code> are used to indicate file structure for
     * file transfers.
     ***/
    public static final int FILE_STRUCTURE = 7;

    /***
     * A constant used to indicate a file is to be treated as a sequence
     * of records.  All constants ending in <code>_STRUCTURE</code>
     * are used to indicate file structure for file transfers.
     ***/
    public static final int RECORD_STRUCTURE = 8;

    /***
     * A constant used to indicate a file is to be treated as a set of
     * independent indexed pages.  All constants ending in
     * <code>_STRUCTURE</code> are used to indicate file structure for file
     * transfers.
     ***/
    public static final int PAGE_STRUCTURE = 9;

    /***
     * A constant used to indicate a file is to be transfered as a stream
     * of bytes.  This is the default transfer mode.  All constants ending
     * in <code>TRANSFER_MODE</code> are used to indicate file transfer
     * modes.
     ***/
    public static final int STREAM_TRANSFER_MODE = 10;

    /***
     * A constant used to indicate a file is to be transfered as a series
     * of blocks.  All constants ending in <code>TRANSFER_MODE</code> are used
     * to indicate file transfer modes.
     ***/
    public static final int BLOCK_TRANSFER_MODE = 11;

    /***
     * A constant used to indicate a file is to be transfered as FTP
     * compressed data.  All constants ending in <code>TRANSFER_MODE</code>
     * are used to indicate file transfer modes.
     ***/
    public static final int COMPRESSED_TRANSFER_MODE = 12;

    // We have to ensure that the protocol communication is in ASCII
    // but we use ISO-8859-1 just in case 8-bit characters cross
    // the wire.
    /**
     * The default character encoding used for communicating over an
     * FTP control connection.  The default encoding is an
     * ASCII-compatible encoding.  Some FTP servers expect other
     * encodings.  You can change the encoding used by an FTP instance
     * with {@link #setControlEncoding setControlEncoding}.
     */
    public static final String DEFAULT_CONTROL_ENCODING = "ISO-8859-1";
    private static final String __modes = "ABILNTCFRPSBC";

    private StringBuffer __commandBuffer;

    BufferedReader _controlInput;
    BufferedWriter _controlOutput;
    int _replyCode;
    Vector _replyLines;
    boolean _newReplyString;
    String _replyString;
    String _controlEncoding;

    /***
     * A ProtocolCommandSupport object used to manage the registering of
     * ProtocolCommandListeners and te firing of ProtocolCommandEvents.
     ***/
    protected ProtocolCommandSupport _commandSupport_;

    /***
     * The default FTP constructor.  Sets the default port to
     * <code>DEFAULT_PORT</code> and initializes internal data structures
     * for saving FTP reply information.
     ***/
    public FTP()
    {
        setDefaultPort(DEFAULT_PORT);
        __commandBuffer = new StringBuffer();
        _replyLines = new Vector();
        _newReplyString = false;
        _replyString = null;
        _commandSupport_ = new ProtocolCommandSupport(this);
        _controlEncoding = DEFAULT_CONTROL_ENCODING;
    }

    private void __getReply() throws IOException
    {
        int length;

        _newReplyString = true;
        _replyLines.setSize(0);

        String line = _controlInput.readLine();

        if (line == null)
            throw new FTPConnectionClosedException(
                "Connection closed without indication.");

        // In case we run into an anomaly we don't want fatal index exceptions
        // to be thrown.
        length = line.length();
        if (length < 3)
            throw new MalformedServerReplyException(
                "Truncated server reply: " + line);

        try
        {
            String code = line.substring(0, 3);
            _replyCode = Integer.parseInt(code);
        }
        catch (NumberFormatException e)
        {
            throw new MalformedServerReplyException(
                "Could not parse response code.\nServer Reply: " + line);
        }

        _replyLines.addElement(line);

        // Get extra lines if message continues.
        if (length > 3 && line.charAt(3) == '-')
        {
            do
            {
                line = _controlInput.readLine();