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.util;
18  
19  import java.io.ByteArrayOutputStream;
20  import java.io.IOException;
21  import java.io.InputStream;
22  import java.io.OutputStream;
23  
24  import org.apache.commons.fileupload.InvalidFileNameException;
25  import org.apache.commons.io.IOUtils;
26  import org.apache.commons.io.output.NullOutputStream;
27  
28  /**
29   * Utility class for working with streams.
30   */
31  public final class Streams {
32  
33      /**
34       * Default buffer size for use in
35       * {@link #copy(InputStream, OutputStream, boolean)}.
36       */
37      public static final int DEFAULT_BUFFER_SIZE = 8192;
38  
39      /**
40       * This convenience method allows to read a
41       * {@link org.apache.commons.fileupload.FileItemStream}'s
42       * content into a string. The platform's default character encoding
43       * is used for converting bytes into characters.
44       *
45       * @param inputStream The input stream to read.
46       * @see #asString(InputStream, String)
47       * @return The streams contents, as a string.
48       * @throws IOException An I/O error occurred.
49       */
50      public static String asString(final InputStream inputStream) throws IOException {
51          final ByteArrayOutputStream baos = new ByteArrayOutputStream();
52          copy(inputStream, baos, true);
53          return baos.toString();
54      }
55  
56      /**
57       * This convenience method allows to read a
58       * {@link org.apache.commons.fileupload.FileItemStream}'s
59       * content into a string, using the given character encoding.
60       *
61       * @param inputStream The input stream to read.
62       * @param encoding The character encoding, typically "UTF-8".
63       * @see #asString(InputStream)
64       * @return The streams contents, as a string.
65       * @throws IOException An I/O error occurred.
66       */
67      public static String asString(final InputStream inputStream, final String encoding) throws IOException {
68          final ByteArrayOutputStream baos = new ByteArrayOutputStream();
69          copy(inputStream, baos, true);
70          return baos.toString(encoding);
71      }
72  
73      /**
74       * Checks, whether the given file name is valid in the sense,
75       * that it doesn't contain any NUL characters. If the file name
76       * is valid, it will be returned without any modifications. Otherwise,
77       * an {@link InvalidFileNameException} is raised.
78       *
79       * @param fileName The file name to check
80       * @return Unmodified file name, if valid.
81       * @throws InvalidFileNameException The file name was found to be invalid.
82       */
83      public static String checkFileName(final String fileName) {
84          if (fileName != null  &&  fileName.indexOf('\u0000') != -1) {
85              // fileName.replace("\u0000", "\\0")
86              final StringBuilder sb = new StringBuilder();
87              for (int i = 0;  i < fileName.length();  i++) {
88                  final char c = fileName.charAt(i);
89                  switch (c) {
90                      case 0:
91                          sb.append("\\0");
92                          break;
93                      default:
94                          sb.append(c);
95                          break;
96                  }
97              }
98              throw new InvalidFileNameException(fileName,
99                      "Invalid file name: " + sb);
100         }
101         return fileName;
102     }
103 
104     /**
105      * Copies the contents of the given {@link InputStream}
106      * to the given {@link OutputStream}. Shortcut for
107      * <pre>
108      *   copy(pInputStream, outputStream, new byte[8192]);
109      * </pre>
110      *
111      * @param inputStream The input stream, which is being read.
112      * It is guaranteed, that {@link InputStream#close()} is called
113      * on the stream.
114      * @param outputStream The output stream, to which data should
115      * be written. May be null, in which case the input streams
116      * contents are simply discarded.
117      * @param closeOutputStream True guarantees, that {@link OutputStream#close()}
118      * is called on the stream. False indicates, that only
119      * {@link OutputStream#flush()} should be called finally.
120      *
121      * @return Number of bytes, which have been copied.
122      * @throws IOException An I/O error occurred.
123      */
124     public static long copy(final InputStream inputStream, final OutputStream outputStream,
125                             final boolean closeOutputStream)
126             throws IOException {
127         return copy(inputStream, outputStream, closeOutputStream, new byte[DEFAULT_BUFFER_SIZE]);
128     }
129 
130     /**
131      * Copies the contents of the given {@link InputStream}
132      * to the given {@link OutputStream}.
133      *
134      * @param inputStream The input stream, which is being read.
135      *   It is guaranteed, that {@link InputStream#close()} is called
136      *   on the stream.
137      * @param outputStream The output stream, to which data should
138      *   be written. May be null, in which case the input streams
139      *   contents are simply discarded.
140      * @param closeOutputStream True guarantees, that {@link OutputStream#close()}
141      *   is called on the stream. False indicates, that only
142      *   {@link OutputStream#flush()} should be called finally.
143      * @param buffer Temporary buffer, which is to be used for
144      *   copying data.
145      * @return Number of bytes, which have been copied.
146      * @throws IOException An I/O error occurred.
147      */
148     public static long copy(final InputStream inputStream, final OutputStream outputStream, final boolean closeOutputStream, final byte[] buffer)
149             throws IOException {
150         try {
151             return IOUtils.copyLarge(inputStream, outputStream != null ? outputStream : NullOutputStream.INSTANCE, buffer);
152         } finally {
153             IOUtils.closeQuietly(inputStream);
154             if (closeOutputStream) {
155                 IOUtils.closeQuietly(outputStream);
156             }
157         }
158     }
159 
160     /**
161      * Private constructor, to prevent instantiation.
162      * This class has only static methods.
163      */
164     private Streams() {
165         // Does nothing
166     }
167 
168 }