1 /*
2 * ====================================================================
3 *
4 * Licensed to the Apache Software Foundation (ASF) under one or more
5 * contributor license agreements. See the NOTICE file distributed with
6 * this work for additional information regarding copyright ownership.
7 * The ASF licenses this file to You under the Apache License, Version 2.0
8 * (the "License"); you may not use this file except in compliance with
9 * 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, software
14 * distributed under the License is distributed on an "AS IS" BASIS,
15 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
16 * See the License for the specific language governing permissions and
17 * limitations under the License.
18 * ====================================================================
19 *
20 * This software consists of voluntary contributions made by many
21 * individuals on behalf of the Apache Software Foundation. For more
22 * information on the Apache Software Foundation, please see
23 * <http://www.apache.org/>.
24 *
25 */
26
27 package org.apache.http.client.protocol;
28
29 import java.io.IOException;
30 import java.util.Locale;
31
32 import org.apache.http.Header;
33 import org.apache.http.HeaderElement;
34 import org.apache.http.HttpEntity;
35 import org.apache.http.HttpException;
36 import org.apache.http.HttpResponse;
37 import org.apache.http.HttpResponseInterceptor;
38 import org.apache.http.annotation.Immutable;
39 import org.apache.http.client.entity.DeflateDecompressingEntity;
40 import org.apache.http.client.entity.GzipDecompressingEntity;
41 import org.apache.http.protocol.HttpContext;
42
43 /**
44 * {@link HttpResponseInterceptor} responsible for processing Content-Encoding
45 * responses.
46 * <p>
47 * Instances of this class are stateless and immutable, therefore threadsafe.
48 *
49 * @since 4.1
50 *
51 */
52 @Immutable
53 public class ResponseContentEncoding implements HttpResponseInterceptor {
54
55 public static final String UNCOMPRESSED = "http.client.response.uncompressed";
56
57 /**
58 * Handles the following {@code Content-Encoding}s by
59 * using the appropriate decompressor to wrap the response Entity:
60 * <ul>
61 * <li>gzip - see {@link GzipDecompressingEntity}</li>
62 * <li>deflate - see {@link DeflateDecompressingEntity}</li>
63 * <li>identity - no action needed</li>
64 * </ul>
65 *
66 * @param response the response which contains the entity
67 * @param context not currently used
68 *
69 * @throws HttpException if the {@code Content-Encoding} is none of the above
70 */
71 public void process(
72 final HttpResponse response,
73 final HttpContext context) throws HttpException, IOException {
74 HttpEntity entity = response.getEntity();
75
76 // entity can be null in case of 304 Not Modified, 204 No Content or similar
77 // check for zero length entity.
78 if (entity != null && entity.getContentLength() != 0) {
79 Header ceheader = entity.getContentEncoding();
80 if (ceheader != null) {
81 HeaderElement[] codecs = ceheader.getElements();
82 for (HeaderElement codec : codecs) {
83 String codecname = codec.getName().toLowerCase(Locale.US);
84 if ("gzip".equals(codecname) || "x-gzip".equals(codecname)) {
85 response.setEntity(new GzipDecompressingEntity(response.getEntity()));
86 if (context != null) context.setAttribute(UNCOMPRESSED, true);
87 return;
88 } else if ("deflate".equals(codecname)) {
89 response.setEntity(new DeflateDecompressingEntity(response.getEntity()));
90 if (context != null) context.setAttribute(UNCOMPRESSED, true);
91 return;
92 } else if ("identity".equals(codecname)) {
93
94 /* Don't need to transform the content - no-op */
95 return;
96 } else {
97 throw new HttpException("Unsupported Content-Coding: " + codec.getName());
98 }
99 }
100 }
101 }
102 }
103
104 }