org.apache.ftpserver.command.RETR.java Source code

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Here is the source code for org.apache.ftpserver.command.RETR.java

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// $Id: RETR.java 328636 2005-10-26 17:38:10 +0530 (Wed, 26 Oct 2005) rana_b $
/*
 * Copyright 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.
 */
package org.apache.ftpserver.command;

import java.io.BufferedInputStream;
import java.io.BufferedOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.net.SocketException;

import org.apache.commons.logging.Log;
import org.apache.ftpserver.Command;
import org.apache.ftpserver.FtpRequestImpl;
import org.apache.ftpserver.FtpWriter;
import org.apache.ftpserver.RequestHandler;
import org.apache.ftpserver.ftplet.DataType;
import org.apache.ftpserver.ftplet.FileObject;
import org.apache.ftpserver.ftplet.FtpException;
import org.apache.ftpserver.ftplet.Ftplet;
import org.apache.ftpserver.ftplet.FtpletEnum;
import org.apache.ftpserver.interfaces.IFtpConfig;
import org.apache.ftpserver.interfaces.IFtpStatistics;
import org.apache.ftpserver.util.IoUtils;

/**
 * <code>RETR &lt;SP&gt; &lt;pathname&gt; &lt;CRLF&gt;</code><br>
 *
 * This command causes the server-DTP to transfer a copy of the
 * file, specified in the pathname, to the server- or user-DTP
 * at the other end of the data connection.  The status and
 * contents of the file at the server site shall be unaffected.
 * 
 * @author <a href="mailto:rana_b@yahoo.com">Rana Bhattacharyya</a>
 */
public class RETR implements Command {

    /**
     * Execute command.
     */
    public void execute(RequestHandler handler, FtpRequestImpl request, FtpWriter out)
            throws IOException, FtpException {

        try {

            // get state variable
            long skipLen = request.getFileOffset();
            IFtpConfig fconfig = handler.getConfig();

            // argument check
            String fileName = request.getArgument();
            if (fileName == null) {
                out.send(501, "RETR", null);
                return;
            }

            // call Ftplet.onDownloadStart() method
            Ftplet ftpletContainer = fconfig.getFtpletContainer();
            FtpletEnum ftpletRet = ftpletContainer.onDownloadStart(request, out);
            if (ftpletRet == FtpletEnum.RET_SKIP) {
                return;
            } else if (ftpletRet == FtpletEnum.RET_DISCONNECT) {
                fconfig.getConnectionManager().closeConnection(handler);
                return;
            }

            // get file object
            FileObject file = null;
            try {
                file = request.getFileSystemView().getFileObject(fileName);
            } catch (Exception ex) {
            }
            if (file == null) {
                out.send(550, "RETR.missing", fileName);
                return;
            }
            fileName = file.getFullName();

            // check file existance
            if (!file.doesExist()) {
                out.send(550, "RETR.missing", fileName);
                return;
            }

            // check valid file
            if (!file.isFile()) {
                out.send(550, "RETR.invalid", fileName);
                return;
            }

            // check permission
            if (!file.hasReadPermission()) {
                out.send(550, "RETR.permission", fileName);
                return;
            }

            // get data connection
            out.send(150, "RETR", null);
            OutputStream os = null;
            try {
                os = request.getDataOutputStream();
            } catch (IOException ex) {
                out.send(425, "RETR", null);
                return;
            }

            // send file data to client
            boolean failure = false;
            BufferedInputStream bis = null;
            BufferedOutputStream bos = null;
            try {

                // open streams
                bis = IoUtils.getBufferedInputStream(openInputStream(handler, file, skipLen));
                bos = IoUtils.getBufferedOutputStream(os);

                // transfer data
                int maxRate = handler.getRequest().getUser().getMaxDownloadRate();
                long transSz = handler.transfer(bis, bos, maxRate);

                // log message
                String userName = request.getUser().getName();
                Log log = fconfig.getLogFactory().getInstance(getClass());
                log.info("File download : " + userName + " - " + fileName);

                // notify the statistics component
                IFtpStatistics ftpStat = (IFtpStatistics) fconfig.getFtpStatistics();
                ftpStat.setDownload(handler, file, transSz);
            } catch (SocketException ex) {
                failure = true;
                out.send(426, "RETR", fileName);
            } catch (IOException ex) {
                failure = true;
                out.send(551, "RETR", fileName);
            } finally {
                IoUtils.close(bis);
                IoUtils.close(bos);
            }

            // if data transfer ok - send transfer complete message
            if (!failure) {
                out.send(226, "RETR", fileName);

                // call Ftplet.onDownloadEnd() method
                ftpletRet = ftpletContainer.onDownloadEnd(request, out);
                if (ftpletRet == FtpletEnum.RET_DISCONNECT) {
                    fconfig.getConnectionManager().closeConnection(handler);
                    return;
                }
            }
        } finally {
            request.resetState();
            request.getFtpDataConnection().closeDataSocket();
        }
    }

    /**
     * Skip length and open input stream.
     */
    public InputStream openInputStream(RequestHandler handler, FileObject file, long skipLen) throws IOException {
        InputStream in;
        if (handler.getDataType() == DataType.ASCII) {
            int c;
            long offset = 0L;
            in = new BufferedInputStream(file.createInputStream(0L));
            while (offset++ < skipLen) {
                if ((c = in.read()) == -1) {
                    throw new IOException("Cannot skip");
                }
                if (c == '\n') {
                    offset++;
                }
            }
        } else {
            in = file.createInputStream(skipLen);
        }
        return in;
    }

}