View Javadoc
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 }