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      1 /*
      2  * Copyright 2008 the original author or authors.
      3  *
      4  * Licensed under the Apache License, Version 2.0 (the "License");
      5  * you may not use this file except in compliance with the License.
      6  * You may obtain a copy of the License at
      7  *
      8  *      http://www.apache.org/licenses/LICENSE-2.0
      9  *
     10  * Unless required by applicable law or agreed to in writing, software
     11  * distributed under the License is distributed on an "AS IS" BASIS,
     12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     13  * See the License for the specific language governing permissions and
     14  * limitations under the License.
     15  */
     16 package org.mockftpserver.fake.command;
     17 
     18 import org.mockftpserver.core.command.Command;
     19 import org.mockftpserver.core.command.ReplyCodes;
     20 import org.mockftpserver.core.session.Session;
     21 import org.mockftpserver.core.session.SessionKeys;
     22 import org.mockftpserver.core.util.IoUtil;
     23 import org.mockftpserver.fake.filesystem.FileEntry;
     24 import org.mockftpserver.fake.filesystem.FileSystemEntry;
     25 import org.mockftpserver.fake.filesystem.FileSystemException;
     26 
     27 import java.io.ByteArrayOutputStream;
     28 import java.io.IOException;
     29 import java.io.InputStream;
     30 
     31 /**
     32  * CommandHandler for the RETR command. Handler logic:
     33  * <ol>
     34  * <li>If the user has not logged in, then reply with 530 and terminate</li>
     35  * <li>If the required pathname parameter is missing, then reply with 501 and terminate</li>
     36  * <li>If the pathname parameter does not specify a valid, existing filename, then reply with 550 and terminate</li>
     37  * <li>If the current user does not have read access to the file at the specified path or execute permission to its directory, then reply with 550 and terminate</li>
     38  * <li>Send an initial reply of 150</li>
     39  * <li>Send the contents of the named file across the data connection</li>
     40  * <li>If there is an error reading the file, then reply with 550 and terminate</li>
     41  * <li>Send a final reply with 226</li>
     42  * </ol>
     43  *
     44  * @author Chris Mair
     45  * @version $Revision$ - $Date$
     46  */
     47 public class RetrCommandHandler extends AbstractFakeCommandHandler {
     48 
     49     protected void handle(Command command, Session session) {
     50         verifyLoggedIn(session);
     51         this.replyCodeForFileSystemException = ReplyCodes.READ_FILE_ERROR;
     52 
     53         String path = getRealPath(session, command.getRequiredParameter(0));
     54         FileSystemEntry entry = getFileSystem().getEntry(path);
     55         verifyFileSystemCondition(entry != null, path, "filesystem.doesNotExist");
     56         verifyFileSystemCondition(!entry.isDirectory(), path, "filesystem.isNotAFile");
     57         FileEntry fileEntry = (FileEntry) entry;
     58 
     59         // User must have read permission to the file
     60         verifyReadPermission(session, path);
     61 
     62         // User must have execute permission to the parent directory
     63         verifyExecutePermission(session, getFileSystem().getParent(path));
     64 
     65         sendReply(session, ReplyCodes.TRANSFER_DATA_INITIAL_OK);
     66         InputStream input = fileEntry.createInputStream();
     67         session.openDataConnection();
     68         byte[] bytes = null;
     69         try {
     70             bytes = IoUtil.readBytes(input);
     71         }
     72         catch (IOException e) {
     73             LOG.error("Error reading from file [" + fileEntry.getPath() + "]", e);
     74             throw new FileSystemException(fileEntry.getPath(), null, e);
     75         }
     76         finally {
     77             try {
     78                 input.close();
     79             }
     80             catch (IOException e) {
     81                 LOG.error("Error closing InputStream for file [" + fileEntry.getPath() + "]", e);
     82             }
     83         }
     84 
     85         if (isAsciiMode(session)) {
     86             bytes = convertLfToCrLf(bytes);
     87         }
     88         session.sendData(bytes, bytes.length);
     89         session.closeDataConnection();
     90         sendReply(session, ReplyCodes.TRANSFER_DATA_FINAL_OK);
     91     }
     92 
     93     /**
     94      * Within the specified byte array, replace all LF (\n) that are NOT preceded by a CR (\r) into CRLF (\r\n).
     95      *
     96      * @param bytes - the bytes to be converted
     97      * @return the result of converting LF to CRLF
     98      */
     99     protected byte[] convertLfToCrLf(byte[] bytes) {
    100         ByteArrayOutputStream out = new ByteArrayOutputStream();
    101         char lastChar = ' ';
    102         for (int i = 0; i < bytes.length; i++) {
    103             char ch = (char) bytes[i];
    104             if (ch == '\n' && lastChar != '\r') {
    105                 out.write('\r');
    106                 out.write('\n');
    107             } else {
    108                 out.write(bytes[i]);
    109             }
    110             lastChar = ch;
    111         }
    112         return out.toByteArray();
    113     }
    114 
    115     private boolean isAsciiMode(Session session) {
    116         // Defaults to true
    117         return session.getAttribute(SessionKeys.ASCII_TYPE) != Boolean.FALSE;
    118     }
    119 
    120 }