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1   /*
2    * ====================================================================
3    * Licensed to the Apache Software Foundation (ASF) under one
4    * or more contributor license agreements.  See the NOTICE file
5    * distributed with this work for additional information
6    * regarding copyright ownership.  The ASF licenses this file
7    * to you under the Apache License, Version 2.0 (the
8    * "License"); you may not use this file except in compliance
9    * with the License.  You may obtain a copy of the License at
10   *
11   *   http://www.apache.org/licenses/LICENSE-2.0
12   *
13   * Unless required by applicable law or agreed to in writing,
14   * software distributed under the License is distributed on an
15   * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
16   * KIND, either express or implied.  See the License for the
17   * specific language governing permissions and limitations
18   * under the License.
19   * ====================================================================
20   *
21   * This software consists of voluntary contributions made by many
22   * individuals on behalf of the Apache Software Foundation.  For more
23   * information on the Apache Software Foundation, please see
24   * <http://www.apache.org/>.
25   *
26   */
27  
28  package org.apache.http.util;
29  
30  import java.io.IOException;
31  import java.io.InputStream;
32  import java.io.InputStreamReader;
33  import java.io.Reader;
34  import java.io.UnsupportedEncodingException;
35  import java.nio.charset.Charset;
36  import java.nio.charset.UnsupportedCharsetException;
37  
38  import org.apache.http.HeaderElement;
39  import org.apache.http.HttpEntity;
40  import org.apache.http.HttpResponse;
41  import org.apache.http.NameValuePair;
42  import org.apache.http.ParseException;
43  import org.apache.http.entity.ContentType;
44  import org.apache.http.protocol.HTTP;
45  
46  /**
47   * Static helpers for dealing with {@link HttpEntity}s.
48   *
49   * @since 4.0
50   */
51  public final class EntityUtils {
52  
53      private static final int DEFAULT_BUFFER_SIZE = 4096;
54  
55      private EntityUtils() {
56      }
57  
58      /**
59       * Ensures that the entity content is fully consumed and the content stream, if exists,
60       * is closed. The process is done, <i>quietly</i> , without throwing any IOException.
61       *
62       * @param entity the entity to consume.
63       *
64       *
65       * @since 4.2
66       */
67      public static void consumeQuietly(final HttpEntity entity) {
68          try {
69            consume(entity);
70          } catch (final IOException ignore) {
71          }
72      }
73  
74      /**
75       * Ensures that the entity content is fully consumed and the content stream, if exists,
76       * is closed.
77       *
78       * @param entity the entity to consume.
79       * @throws IOException if an error occurs reading the input stream
80       *
81       * @since 4.1
82       */
83      public static void consume(final HttpEntity entity) throws IOException {
84          if (entity == null) {
85              return;
86          }
87          if (entity.isStreaming()) {
88              final InputStream instream = entity.getContent();
89              if (instream != null) {
90                  instream.close();
91              }
92          }
93      }
94  
95      /**
96       * Updates an entity in a response by first consuming an existing entity, then setting the new one.
97       *
98       * @param response the response with an entity to update; must not be null.
99       * @param entity the entity to set in the response.
100      * @throws IOException if an error occurs while reading the input stream on the existing
101      * entity.
102      * @throws IllegalArgumentException if response is null.
103      *
104      * @since 4.3
105      */
106     public static void updateEntity(
107             final HttpResponse response, final HttpEntity entity) throws IOException {
108         Args.notNull(response, "Response");
109         consume(response.getEntity());
110         response.setEntity(entity);
111     }
112 
113     /**
114      * Read the contents of an entity and return it as a byte array.
115      *
116      * @param entity the entity to read from=
117      * @return byte array containing the entity content. May be null if
118      *   {@link HttpEntity#getContent()} is null.
119      * @throws IOException if an error occurs reading the input stream
120      * @throws IllegalArgumentException if entity is null or if content length &gt; Integer.MAX_VALUE
121      */
122     public static byte[] toByteArray(final HttpEntity entity) throws IOException {
123         Args.notNull(entity, "Entity");
124         final InputStream instream = entity.getContent();
125         if (instream == null) {
126             return null;
127         }
128         try {
129             Args.check(entity.getContentLength() <= Integer.MAX_VALUE,
130                     "HTTP entity too large to be buffered in memory");
131             int capacity = (int)entity.getContentLength();
132             if (capacity < 0) {
133                 capacity = DEFAULT_BUFFER_SIZE;
134             }
135             final ByteArrayBuffer buffer = new ByteArrayBuffer(capacity);
136             final byte[] tmp = new byte[DEFAULT_BUFFER_SIZE];
137             int l;
138             while((l = instream.read(tmp)) != -1) {
139                 buffer.append(tmp, 0, l);
140             }
141             return buffer.toByteArray();
142         } finally {
143             instream.close();
144         }
145     }
146 
147     /**
148      * Obtains character set of the entity, if known.
149      *
150      * @param entity must not be null
151      * @return the character set, or null if not found
152      * @throws ParseException if header elements cannot be parsed
153      * @throws IllegalArgumentException if entity is null
154      *
155      * @deprecated (4.1.3) use {@link ContentType#getOrDefault(HttpEntity)}
156      */
157     @Deprecated
158     public static String getContentCharSet(final HttpEntity entity) throws ParseException {
159         Args.notNull(entity, "Entity");
160         String charset = null;
161         if (entity.getContentType() != null) {
162             final HeaderElement values[] = entity.getContentType().getElements();
163             if (values.length > 0) {
164                 final NameValuePair param = values[0].getParameterByName("charset");
165                 if (param != null) {
166                     charset = param.getValue();
167                 }
168             }
169         }
170         return charset;
171     }
172 
173     /**
174      * Obtains MIME type of the entity, if known.
175      *
176      * @param entity must not be null
177      * @return the character set, or null if not found
178      * @throws ParseException if header elements cannot be parsed
179      * @throws IllegalArgumentException if entity is null
180      *
181      * @since 4.1
182      *
183      * @deprecated (4.1.3) use {@link ContentType#getOrDefault(HttpEntity)}
184      */
185     @Deprecated
186     public static String getContentMimeType(final HttpEntity entity) throws ParseException {
187         Args.notNull(entity, "Entity");
188         String mimeType = null;
189         if (entity.getContentType() != null) {
190             final HeaderElement values[] = entity.getContentType().getElements();
191             if (values.length > 0) {
192                 mimeType = values[0].getName();
193             }
194         }
195         return mimeType;
196     }
197 
198     private static String toString(
199             final HttpEntity entity,
200             final ContentType contentType) throws IOException {
201         final InputStream instream = entity.getContent();
202         if (instream == null) {
203             return null;
204         }
205         try {
206             Args.check(entity.getContentLength() <= Integer.MAX_VALUE,
207                     "HTTP entity too large to be buffered in memory");
208             int capacity = (int)entity.getContentLength();
209             if (capacity < 0) {
210                 capacity = DEFAULT_BUFFER_SIZE;
211             }
212             Charset charset = null;
213             if (contentType != null) {
214                 charset = contentType.getCharset();
215                 if (charset == null) {
216                     final ContentType defaultContentType = ContentType.getByMimeType(contentType.getMimeType());
217                     charset = defaultContentType != null ? defaultContentType.getCharset() : null;
218                 }
219             }
220             if (charset == null) {
221                 charset = HTTP.DEF_CONTENT_CHARSET;
222             }
223             final Reader reader = new InputStreamReader(instream, charset);
224             final CharArrayBuffer buffer = new CharArrayBuffer(capacity);
225             final char[] tmp = new char[1024];
226             int l;
227             while((l = reader.read(tmp)) != -1) {
228                 buffer.append(tmp, 0, l);
229             }
230             return buffer.toString();
231         } finally {
232             instream.close();
233         }
234     }
235 
236     /**
237      * Get the entity content as a String, using the provided default character set
238      * if none is found in the entity.
239      * If defaultCharset is null, the default "ISO-8859-1" is used.
240      *
241      * @param entity must not be null
242      * @param defaultCharset character set to be applied if none found in the entity,
243      * or if the entity provided charset is invalid or not available.
244      * @return the entity content as a String. May be null if
245      *   {@link HttpEntity#getContent()} is null.
246      * @throws ParseException if header elements cannot be parsed
247      * @throws IllegalArgumentException if entity is null or if content length &gt; Integer.MAX_VALUE
248      * @throws IOException if an error occurs reading the input stream
249      * @throws java.nio.charset.UnsupportedCharsetException Thrown when the named entity's charset is not available in
250      * this instance of the Java virtual machine and no defaultCharset is provided.
251      */
252     public static String toString(
253             final HttpEntity entity, final Charset defaultCharset) throws IOException, ParseException {
254         Args.notNull(entity, "Entity");
255         ContentType contentType = null;
256         try {
257             contentType = ContentType.get(entity);
258         } catch (final UnsupportedCharsetException ex) {
259             if (defaultCharset == null) {
260                 throw new UnsupportedEncodingException(ex.getMessage());
261             }
262         }
263         if (contentType != null) {
264             if (contentType.getCharset() == null) {
265                 contentType = contentType.withCharset(defaultCharset);
266             }
267         } else {
268             contentType = ContentType.DEFAULT_TEXT.withCharset(defaultCharset);
269         }
270         return toString(entity, contentType);
271     }
272 
273     /**
274      * Get the entity content as a String, using the provided default character set
275      * if none is found in the entity.
276      * If defaultCharset is null, the default "ISO-8859-1" is used.
277      *
278      * @param entity must not be null
279      * @param defaultCharset character set to be applied if none found in the entity
280      * @return the entity content as a String. May be null if
281      *   {@link HttpEntity#getContent()} is null.
282      * @throws ParseException if header elements cannot be parsed
283      * @throws IllegalArgumentException if entity is null or if content length &gt; Integer.MAX_VALUE
284      * @throws IOException if an error occurs reading the input stream
285      * @throws java.nio.charset.UnsupportedCharsetException Thrown when the named charset is not available in
286      * this instance of the Java virtual machine
287      */
288     public static String toString(
289             final HttpEntity entity, final String defaultCharset) throws IOException, ParseException {
290         return toString(entity, defaultCharset != null ? Charset.forName(defaultCharset) : null);
291     }
292 
293     /**
294      * Read the contents of an entity and return it as a String.
295      * The content is converted using the character set from the entity (if any),
296      * failing that, "ISO-8859-1" is used.
297      *
298      * @param entity the entity to convert to a string; must not be null
299      * @return String containing the content.
300      * @throws ParseException if header elements cannot be parsed
301      * @throws IllegalArgumentException if entity is null or if content length &gt; Integer.MAX_VALUE
302      * @throws IOException if an error occurs reading the input stream
303      * @throws java.nio.charset.UnsupportedCharsetException Thrown when the named charset is not available in
304      * this instance of the Java virtual machine
305      */
306     public static String toString(final HttpEntity entity) throws IOException, ParseException {
307         Args.notNull(entity, "Entity");
308         return toString(entity, ContentType.get(entity));
309     }
310 
311 }