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    1   /*
    2    * Licensed to the Apache Software Foundation (ASF) under one or more
    3    * contributor license agreements.  See the NOTICE file distributed with
    4    * this work for additional information regarding copyright ownership.
    5    * The ASF licenses this file to You under the Apache License, Version 2.0
    6    * (the "License"); you may not use this file except in compliance with
    7    * the License.  You may obtain a copy of the License at
    8    *
    9    *      http://www.apache.org/licenses/LICENSE-2.0
    10   *
    11   * Unless required by applicable law or agreed to in writing, software
    12   * distributed under the License is distributed on an "AS IS" BASIS,
    13   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    14   * See the License for the specific language governing permissions and
    15   * limitations under the License.
    16   */
    17  package org.apache.commons.fileupload.disk;
    18
    19  import java.io.File;
    20
    21  import org.apache.commons.fileupload.FileItem;
    22  import org.apache.commons.fileupload.FileItemFactory;
    23  import org.apache.commons.io.FileCleaningTracker;
    24
    25  /**
    26   * <p>The default {@link org.apache.commons.fileupload.FileItemFactory}
    27   * implementation. This implementation creates
    28   * {@link org.apache.commons.fileupload.FileItem} instances which keep their
    29   * content either in memory, for smaller items, or in a temporary file on disk,
    30   * for larger items. The size threshold, above which content will be stored on
    31   * disk, is configurable, as is the directory in which temporary files will be
    32   * created.</p>
    33   *
    34   * <p>If not otherwise configured, the default configuration values are as
    35   * follows:</p>
    36   * <ul>
    37   *   <li>Size threshold is 10KB.</li>
    38   *   <li>Repository is the system default temp directory, as returned by
    39   *       <code>System.getProperty("java.io.tmpdir")</code>.</li>
    40   * </ul>
    41   * <p>
    42   * <b>NOTE</b>: Files are created in the system default temp directory with
    43   * predictable names. This means that a local attacker with write access to that
    44   * directory can perform a TOUTOC attack to replace any uploaded file with a
    45   * file of the attackers choice. The implications of this will depend on how the
    46   * uploaded file is used but could be significant. When using this
    47   * implementation in an environment with local, untrusted users,
    48   * {@link #setRepository(File)} MUST be used to configure a repository location
    49   * that is not publicly writable. In a Servlet container the location identified
    50   * by the ServletContext attribute <code>javax.servlet.context.tempdir</code>
    51   * may be used.
    52   * </p>
    53   *
    54   * <p>Temporary files, which are created for file items, should be
    55   * deleted later on. The best way to do this is using a
    56   * {@link FileCleaningTracker}, which you can set on the
    57   * {@link DiskFileItemFactory}. However, if you do use such a tracker,
    58   * then you must consider the following: Temporary files are automatically
    59   * deleted as soon as they are no longer needed. (More precisely, when the
    60   * corresponding instance of {@link java.io.File} is garbage collected.)
    61   * This is done by the so-called reaper thread, which is started and stopped
    62   * automatically by the {@link FileCleaningTracker} when there are files to be
    63   * tracked.
    64   * It might make sense to terminate that thread, for example, if
    65   * your web application ends. See the section on "Resource cleanup"
    66   * in the users guide of commons-fileupload.</p>
    67   *
    68   * @since FileUpload 1.1
    69   */
    70  public class DiskFileItemFactory implements FileItemFactory {
    71
    72      // ----------------------------------------------------- Manifest constants
    73
    74      /**
    75       * The default threshold above which uploads will be stored on disk.
    76       */
    77      public static final int DEFAULT_SIZE_THRESHOLD = 10240;
    78
    79      // ----------------------------------------------------- Instance Variables
    80
    81      /**
    82       * The directory in which uploaded files will be stored, if stored on disk.
    83       */
    84      private File repository;
    85
    86      /**
    87       * The threshold above which uploads will be stored on disk.
    88       */
    89      private int sizeThreshold = DEFAULT_SIZE_THRESHOLD;
    90
    91      /**
    92       * <p>The instance of {@link FileCleaningTracker}, which is responsible
    93       * for deleting temporary files.</p>
    94       * <p>May be null, if tracking files is not required.</p>
    95       */
    96      private FileCleaningTracker fileCleaningTracker;
    97
    98      // ----------------------------------------------------------- Constructors
    99
    100     /**
    101      * Constructs an unconfigured instance of this class. The resulting factory
    102      * may be configured by calling the appropriate setter methods.
    103      */
    104     public DiskFileItemFactory() {
    105         this(DEFAULT_SIZE_THRESHOLD, null);
    106     }
    107
    108     /**
    109      * Constructs a preconfigured instance of this class.
    110      *
    111      * @param sizeThreshold The threshold, in bytes, below which items will be
    112      *                      retained in memory and above which they will be
    113      *                      stored as a file.
    114      * @param repository    The data repository, which is the directory in
    115      *                      which files will be created, should the item size
    116      *                      exceed the threshold.
    117      */
    118     public DiskFileItemFactory(int sizeThreshold, File repository) {
    119         this.sizeThreshold = sizeThreshold;
    120         this.repository = repository;
    121     }
    122
    123     // ------------------------------------------------------------- Properties
    124
    125     /**
    126      * Returns the directory used to temporarily store files that are larger
    127      * than the configured size threshold.
    128      *
    129      * @return The directory in which temporary files will be located.
    130      *
    131      * @see #setRepository(java.io.File)
    132      *
    133      */
    134     public File getRepository() {
    135         return repository;
    136     }
    137
    138     /**
    139      * Sets the directory used to temporarily store files that are larger
    140      * than the configured size threshold.
    141      *
    142      * @param repository The directory in which temporary files will be located.
    143      *
    144      * @see #getRepository()
    145      *
    146      */
    147     public void setRepository(File repository) {
    148         this.repository = repository;
    149     }
    150
    151     /**
    152      * Returns the size threshold beyond which files are written directly to
    153      * disk. The default value is 10240 bytes.
    154      *
    155      * @return The size threshold, in bytes.
    156      *
    157      * @see #setSizeThreshold(int)
    158      */
    159     public int getSizeThreshold() {
    160         return sizeThreshold;
    161     }
    162
    163     /**
    164      * Sets the size threshold beyond which files are written directly to disk.
    165      *
    166      * @param sizeThreshold The size threshold, in bytes.
    167      *
    168      * @see #getSizeThreshold()
    169      *
    170      */
    171     public void setSizeThreshold(int sizeThreshold) {
    172         this.sizeThreshold = sizeThreshold;
    173     }
    174
    175     // --------------------------------------------------------- Public Methods
    176
    177     /**
    178      * Create a new {@link org.apache.commons.fileupload.disk.DiskFileItem}
    179      * instance from the supplied parameters and the local factory
    180      * configuration.
    181      *
    182      * @param fieldName   The name of the form field.
    183      * @param contentType The content type of the form field.
    184      * @param isFormField <code>true</code> if this is a plain form field;
    185      *                    <code>false</code> otherwise.
    186      * @param fileName    The name of the uploaded file, if any, as supplied
    187      *                    by the browser or other client.
    188      *
    189      * @return The newly created file item.
    190      */
    191     public FileItem createItem(String fieldName, String contentType,
    192             boolean isFormField, String fileName) {
    193         DiskFileItem result = new DiskFileItem(fieldName, contentType,
    194                 isFormField, fileName, sizeThreshold, repository);
    195         FileCleaningTracker tracker = getFileCleaningTracker();
    196         if (tracker != null) {
    197             tracker.track(result.getTempFile(), result);
    198         }
    199         return result;
    200     }
    201
    202     /**
    203      * Returns the tracker, which is responsible for deleting temporary
    204      * files.
    205      *
    206      * @return An instance of {@link FileCleaningTracker}, or null
    207      *   (default), if temporary files aren't tracked.
    208      */
    209     public FileCleaningTracker getFileCleaningTracker() {
    210         return fileCleaningTracker;
    211     }
    212
    213     /**
    214      * Sets the tracker, which is responsible for deleting temporary
    215      * files.
    216      *
    217      * @param pTracker An instance of {@link FileCleaningTracker},
    218      *   which will from now on track the created files, or null
    219      *   (default), to disable tracking.
    220      */
    221     public void setFileCleaningTracker(FileCleaningTracker pTracker) {
    222         fileCleaningTracker = pTracker;
    223     }
    224
    225 }