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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")}.</li>
    40   * </ul>
    41   * <p>
    42   * <strong>NOTE</strong>: 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}
    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      /**
    73       * The default threshold above which uploads will be stored on disk.
    74       */
    75      public static final int DEFAULT_SIZE_THRESHOLD = 10240;
    76
    77      /**
    78       * The directory in which uploaded files will be stored, if stored on disk.
    79       */
    80      private File repository;
    81
    82      /**
    83       * The threshold above which uploads will be stored on disk.
    84       */
    85      private int sizeThreshold = DEFAULT_SIZE_THRESHOLD;
    86
    87      /**
    88       * <p>The instance of {@link FileCleaningTracker}, which is responsible
    89       * for deleting temporary files.</p>
    90       * <p>May be null, if tracking files is not required.</p>
    91       */
    92      private FileCleaningTracker fileCleaningTracker;
    93
    94      /**
    95       * Default content charset to be used when no explicit charset
    96       * parameter is provided by the sender.
    97       */
    98      private String defaultCharset = DiskFileItem.DEFAULT_CHARSET;
    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(final int sizeThreshold, final File repository) {
    119         this.sizeThreshold = sizeThreshold;
    120         this.repository = repository;
    121     }
    122
    123     /**
    124      * Create a new {@link DiskFileItem}
    125      * instance from the supplied parameters and the local factory
    126      * configuration.
    127      *
    128      * @param fieldName   The name of the form field.
    129      * @param contentType The content type of the form field.
    130      * @param isFormField {@code true} if this is a plain form field;
    131      *                    {@code false} otherwise.
    132      * @param fileName    The name of the uploaded file, if any, as supplied
    133      *                    by the browser or other client.
    134      *
    135      * @return The newly created file item.
    136      */
    137     @Override
    138     public FileItem createItem(final String fieldName, final String contentType,
    139             final boolean isFormField, final String fileName) {
    140         final DiskFileItem result = new DiskFileItem(fieldName, contentType,
    141                 isFormField, fileName, sizeThreshold, repository);
    142         result.setDefaultCharset(defaultCharset);
    143         final FileCleaningTracker tracker = getFileCleaningTracker();
    144         if (tracker != null) {
    145             tracker.track(result.getTempFile(), result);
    146         }
    147         return result;
    148     }
    149
    150     /**
    151      * Gets the default charset for use when no explicit charset
    152      * parameter is provided by the sender.
    153      * @return the default charset
    154      */
    155     public String getDefaultCharset() {
    156         return defaultCharset;
    157     }
    158
    159     /**
    160      * Gets the tracker, which is responsible for deleting temporary
    161      * files.
    162      *
    163      * @return An instance of {@link FileCleaningTracker}, or null
    164      *   (default), if temporary files aren't tracked.
    165      */
    166     public FileCleaningTracker getFileCleaningTracker() {
    167         return fileCleaningTracker;
    168     }
    169
    170     /**
    171      * Gets the directory used to temporarily store files that are larger
    172      * than the configured size threshold.
    173      *
    174      * @return The directory in which temporary files will be located.
    175      * @see #setRepository(java.io.File)
    176      *
    177      */
    178     public File getRepository() {
    179         return repository;
    180     }
    181
    182     /**
    183      * Gets the size threshold beyond which files are written directly to
    184      * disk. The default value is 10240 bytes.
    185      *
    186      * @return The size threshold, in bytes.
    187      * @see #setSizeThreshold(int)
    188      */
    189     public int getSizeThreshold() {
    190         return sizeThreshold;
    191     }
    192
    193     /**
    194      * Sets the default charset for use when no explicit charset
    195      * parameter is provided by the sender.
    196      *
    197      * @param charset the default charset
    198      */
    199     public void setDefaultCharset(final String charset) {
    200         this.defaultCharset = charset;
    201     }
    202
    203     /**
    204      * Sets the tracker, which is responsible for deleting temporary
    205      * files.
    206      *
    207      * @param fileCleaningTracker An instance of {@link FileCleaningTracker},
    208      *   which will from now on track the created files, or null
    209      *   (default), to disable tracking.
    210      */
    211     public void setFileCleaningTracker(final FileCleaningTracker fileCleaningTracker) {
    212         this.fileCleaningTracker = fileCleaningTracker;
    213     }
    214
    215     /**
    216      * Sets the directory used to temporarily store files that are larger
    217      * than the configured size threshold.
    218      *
    219      * @param repository The directory in which temporary files will be located.
    220      * @see #getRepository()
    221      *
    222      */
    223     public void setRepository(final File repository) {
    224         this.repository = repository;
    225     }
    226
    227     /**
    228      * Sets the size threshold beyond which files are written directly to disk.
    229      *
    230      * @param sizeThreshold The size threshold, in bytes.
    231      * @see #getSizeThreshold()
    232      *
    233      */
    234     public void setSizeThreshold(final int sizeThreshold) {
    235         this.sizeThreshold = sizeThreshold;
    236     }
    237 }