    001/*
    002 * Licensed to the Apache Software Foundation (ASF) under one or more
    003 * contributor license agreements.  See the NOTICE file distributed with
    004 * this work for additional information regarding copyright ownership.
    005 * The ASF licenses this file to You under the Apache License, Version 2.0
    006 * (the "License"); you may not use this file except in compliance with
    007 * the License.  You may obtain a copy of the License at
    008 *
    009 *      http://www.apache.org/licenses/LICENSE-2.0
    010 *
    011 * Unless required by applicable law or agreed to in writing, software
    012 * distributed under the License is distributed on an "AS IS" BASIS,
    013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    014 * See the License for the specific language governing permissions and
    015 * limitations under the License.
    016 */
    017package org.apache.commons.fileupload.disk;
    018
    019import java.io.File;
    020
    021import org.apache.commons.fileupload.FileItem;
    022import org.apache.commons.fileupload.FileItemFactory;
    023import org.apache.commons.io.FileCleaningTracker;
    024
    025/**
    026 * <p>The default {@link org.apache.commons.fileupload.FileItemFactory}
    027 * implementation. This implementation creates
    028 * {@link org.apache.commons.fileupload.FileItem} instances which keep their
    029 * content either in memory, for smaller items, or in a temporary file on disk,
    030 * for larger items. The size threshold, above which content will be stored on
    031 * disk, is configurable, as is the directory in which temporary files will be
    032 * created.</p>
    033 *
    034 * <p>If not otherwise configured, the default configuration values are as
    035 * follows:</p>
    036 * <ul>
    037 *   <li>Size threshold is 10KB.</li>
    038 *   <li>Repository is the system default temp directory, as returned by
    039 *       <code>System.getProperty("java.io.tmpdir")</code>.</li>
    040 * </ul>
    041 * <p>
    042 * <b>NOTE</b>: Files are created in the system default temp directory with
    043 * predictable names. This means that a local attacker with write access to that
    044 * directory can perform a TOUTOC attack to replace any uploaded file with a
    045 * file of the attackers choice. The implications of this will depend on how the
    046 * uploaded file is used but could be significant. When using this
    047 * implementation in an environment with local, untrusted users,
    048 * {@link #setRepository(File)} MUST be used to configure a repository location
    049 * that is not publicly writable. In a Servlet container the location identified
    050 * by the ServletContext attribute <code>javax.servlet.context.tempdir</code>
    051 * may be used.
    052 * </p>
    053 *
    054 * <p>Temporary files, which are created for file items, should be
    055 * deleted later on. The best way to do this is using a
    056 * {@link FileCleaningTracker}, which you can set on the
    057 * {@link DiskFileItemFactory}. However, if you do use such a tracker,
    058 * then you must consider the following: Temporary files are automatically
    059 * deleted as soon as they are no longer needed. (More precisely, when the
    060 * corresponding instance of {@link java.io.File} is garbage collected.)
    061 * This is done by the so-called reaper thread, which is started and stopped
    062 * automatically by the {@link FileCleaningTracker} when there are files to be
    063 * tracked.
    064 * It might make sense to terminate that thread, for example, if
    065 * your web application ends. See the section on "Resource cleanup"
    066 * in the users guide of commons-fileupload.</p>
    067 *
    068 * @since FileUpload 1.1
    069 */
    070public class DiskFileItemFactory implements FileItemFactory {
    071
    072    // ----------------------------------------------------- Manifest constants
    073
    074    /**
    075     * The default threshold above which uploads will be stored on disk.
    076     */
    077    public static final int DEFAULT_SIZE_THRESHOLD = 10240;
    078
    079    // ----------------------------------------------------- Instance Variables
    080
    081    /**
    082     * The directory in which uploaded files will be stored, if stored on disk.
    083     */
    084    private File repository;
    085
    086    /**
    087     * The threshold above which uploads will be stored on disk.
    088     */
    089    private int sizeThreshold = DEFAULT_SIZE_THRESHOLD;
    090
    091    /**
    092     * <p>The instance of {@link FileCleaningTracker}, which is responsible
    093     * for deleting temporary files.</p>
    094     * <p>May be null, if tracking files is not required.</p>
    095     */
    096    private FileCleaningTracker fileCleaningTracker;
    097
    098    // ----------------------------------------------------------- Constructors
    099
    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}