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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 }