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.util.List;
31
32 import org.apache.http.HttpException;
33 import org.apache.http.HttpRequest;
34 import org.apache.http.HttpRequestInterceptor;
35 import org.apache.http.annotation.Contract;
36 import org.apache.http.annotation.ThreadingBehavior;
37 import org.apache.http.client.config.RequestConfig;
38 import org.apache.http.protocol.HttpContext;
39
40 /**
41 * Class responsible for handling Content Encoding requests in HTTP.
42 * <p>
43 * Instances of this class are stateless, therefore they're thread-safe and immutable.
44 *
45 * @see "http://www.w3.org/Protocols/rfc2616/rfc2616-sec3.html#sec3.5"
46 *
47 * @since 4.1
48 */
49 @Contract(threading = ThreadingBehavior.IMMUTABLE)
50 public class RequestAcceptEncoding implements HttpRequestInterceptor {
51
52 private final String acceptEncoding;
53
54 /**
55 * @since 4.4
56 */
57 public RequestAcceptEncoding(final List<String> encodings) {
58 if (encodings != null && !encodings.isEmpty()) {
59 final StringBuilder buf = new StringBuilder();
60 for (int i = 0; i < encodings.size(); i++) {
61 if (i > 0) {
62 buf.append(",");
63 }
64 buf.append(encodings.get(i));
65 }
66 this.acceptEncoding = buf.toString();
67 } else {
68 this.acceptEncoding = "gzip,deflate";
69 }
70 }
71
72 public RequestAcceptEncoding() {
73 this(null);
74 }
75
76 @Override
77 public void process(
78 final HttpRequest request,
79 final HttpContext context) throws HttpException, IOException {
80
81 final HttpClientContext clientContext = HttpClientContext.adapt(context);
82 final RequestConfig requestConfig = clientContext.getRequestConfig();
83
84 /* Signal support for Accept-Encoding transfer encodings. */
85 if (!request.containsHeader("Accept-Encoding") && requestConfig.isContentCompressionEnabled()) {
86 request.addHeader("Accept-Encoding", acceptEncoding);
87 }
88 }
89
90 }