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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  package org.apache.http.client.protocol;
28  
29  import java.io.IOException;
30  import java.io.InputStream;
31  import java.util.Locale;
32  import java.util.zip.GZIPInputStream;
33  
34  import org.apache.http.Header;
35  import org.apache.http.HeaderElement;
36  import org.apache.http.HttpEntity;
37  import org.apache.http.HttpException;
38  import org.apache.http.HttpResponse;
39  import org.apache.http.HttpResponseInterceptor;
40  import org.apache.http.annotation.Contract;
41  import org.apache.http.annotation.ThreadingBehavior;
42  import org.apache.http.client.config.RequestConfig;
43  import org.apache.http.client.entity.DecompressingEntity;
44  import org.apache.http.client.entity.DeflateInputStream;
45  import org.apache.http.client.entity.InputStreamFactory;
46  import org.apache.http.config.Lookup;
47  import org.apache.http.config.RegistryBuilder;
48  import org.apache.http.protocol.HttpContext;
49  
50  /**
51   * {@link HttpResponseInterceptor} responsible for processing Content-Encoding
52   * responses.
53   * <p>
54   * Instances of this class are stateless and immutable, therefore threadsafe.
55   *
56   * @since 4.1
57   *
58   */
59  @Contract(threading = ThreadingBehavior.IMMUTABLE_CONDITIONAL)
60  public class ResponseContentEncoding implements HttpResponseInterceptor {
61  
62      public static final String UNCOMPRESSED = "http.client.response.uncompressed";
63  
64      private final static InputStreamFactory GZIP = new InputStreamFactory() {
65  
66          @Override
67          public InputStream create(final InputStream instream) throws IOException {
68              return new GZIPInputStream(instream);
69          }
70      };
71  
72      private final static InputStreamFactory DEFLATE = new InputStreamFactory() {
73  
74          @Override
75          public InputStream create(final InputStream instream) throws IOException {
76              return new DeflateInputStream(instream);
77          }
78  
79      };
80  
81      private final Lookup<InputStreamFactory> decoderRegistry;
82      private final boolean ignoreUnknown;
83  
84      /**
85       * @since 4.5
86       */
87      public ResponseContentEncoding(final Lookup<InputStreamFactory> decoderRegistry, final boolean ignoreUnknown) {
88          this.decoderRegistry = decoderRegistry != null ? decoderRegistry :
89              RegistryBuilder.<InputStreamFactory>create()
90                      .register("gzip", GZIP)
91                      .register("x-gzip", GZIP)
92                      .register("deflate", DEFLATE)
93                      .build();
94          this.ignoreUnknown = ignoreUnknown;
95      }
96  
97      /**
98       * @since 4.5
99       */
100     public ResponseContentEncoding(final boolean ignoreUnknown) {
101         this(null, ignoreUnknown);
102     }
103 
104     /**
105      * @since 4.4
106      */
107     public ResponseContentEncoding(final Lookup<InputStreamFactory> decoderRegistry) {
108         this(decoderRegistry, true);
109     }
110 
111     /**
112      * Handles {@code gzip} and {@code deflate} compressed entities by using the following
113      * decoders:
114      * <ul>
115      * <li>gzip - see {@link GZIPInputStream}</li>
116      * <li>deflate - see {@link DeflateInputStream}</li>
117      * </ul>
118      */
119     public ResponseContentEncoding() {
120         this(null);
121     }
122 
123     @Override
124     public void process(
125             final HttpResponse response,
126             final HttpContext context) throws HttpException, IOException {
127         final HttpEntity entity = response.getEntity();
128 
129         final HttpClientContext clientContext = HttpClientContext.adapt(context);
130         final RequestConfig requestConfig = clientContext.getRequestConfig();
131         // entity can be null in case of 304 Not Modified, 204 No Content or similar
132         // check for zero length entity.
133         if (requestConfig.isContentCompressionEnabled() && entity != null && entity.getContentLength() != 0) {
134             final Header ceheader = entity.getContentEncoding();
135             if (ceheader != null) {
136                 final HeaderElement[] codecs = ceheader.getElements();
137                 for (final HeaderElement codec : codecs) {
138                     final String codecname = codec.getName().toLowerCase(Locale.ROOT);
139                     final InputStreamFactory decoderFactory = decoderRegistry.lookup(codecname);
140                     if (decoderFactory != null) {
141                         response.setEntity(new DecompressingEntity(response.getEntity(), decoderFactory));
142                         response.removeHeaders("Content-Length");
143                         response.removeHeaders("Content-Encoding");
144                         response.removeHeaders("Content-MD5");
145                     } else {
146                         if (!"identity".equals(codecname) && !ignoreUnknown) {
147                             throw new HttpException("Unsupported Content-Encoding: " + codec.getName());
148                         }
149                     }
150                 }
151             }
152         }
153     }
154 
155 }