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.protocol;
29
30 import java.io.IOException;
31
32 import org.apache.http.HttpEntity;
33 import org.apache.http.HttpException;
34 import org.apache.http.HttpResponse;
35 import org.apache.http.HttpResponseInterceptor;
36 import org.apache.http.HttpStatus;
37 import org.apache.http.HttpVersion;
38 import org.apache.http.ProtocolException;
39 import org.apache.http.ProtocolVersion;
40 import org.apache.http.annotation.ThreadingBehavior;
41 import org.apache.http.annotation.Contract;
42 import org.apache.http.util.Args;
43
44 /**
45 * ResponseContent is the most important interceptor for outgoing responses.
46 * It is responsible for delimiting content length by adding
47 * {@code Content-Length} or {@code Transfer-Content} headers based
48 * on the properties of the enclosed entity and the protocol version.
49 * This interceptor is required for correct functioning of server side protocol
50 * processors.
51 *
52 * @since 4.0
53 */
54 @Contract(threading = ThreadingBehavior.IMMUTABLE)
55 public class ResponseContent implements HttpResponseInterceptor {
56
57 private final boolean overwrite;
58
59 /**
60 * Default constructor. The {@code Content-Length} or {@code Transfer-Encoding}
61 * will cause the interceptor to throw {@link ProtocolException} if already present in the
62 * response message.
63 */
64 public ResponseContent() {
65 this(false);
66 }
67
68 /**
69 * Constructor that can be used to fine-tune behavior of this interceptor.
70 *
71 * @param overwrite If set to {@code true} the {@code Content-Length} and
72 * {@code Transfer-Encoding} headers will be created or updated if already present.
73 * If set to {@code false} the {@code Content-Length} and
74 * {@code Transfer-Encoding} headers will cause the interceptor to throw
75 * {@link ProtocolException} if already present in the response message.
76 *
77 * @since 4.2
78 */
79 public ResponseContent(final boolean overwrite) {
80 super();
81 this.overwrite = overwrite;
82 }
83
84 /**
85 * Processes the response (possibly updating or inserting) Content-Length and Transfer-Encoding headers.
86 * @param response The HttpResponse to modify.
87 * @param context Unused.
88 * @throws ProtocolException If either the Content-Length or Transfer-Encoding headers are found.
89 * @throws IllegalArgumentException If the response is null.
90 */
91 @Override
92 public void process(final HttpResponse response, final HttpContext context)
93 throws HttpException, IOException {
94 Args.notNull(response, "HTTP response");
95 if (this.overwrite) {
96 response.removeHeaders(HTTP.TRANSFER_ENCODING);
97 response.removeHeaders(HTTP.CONTENT_LEN);
98 } else {
99 if (response.containsHeader(HTTP.TRANSFER_ENCODING)) {
100 throw new ProtocolException("Transfer-encoding header already present");
101 }
102 if (response.containsHeader(HTTP.CONTENT_LEN)) {
103 throw new ProtocolException("Content-Length header already present");
104 }
105 }
106 final ProtocolVersion ver = response.getStatusLine().getProtocolVersion();
107 final HttpEntity entity = response.getEntity();
108 if (entity != null) {
109 final long len = entity.getContentLength();
110 if (entity.isChunked() && !ver.lessEquals(HttpVersion.HTTP_1_0)) {
111 response.addHeader(HTTP.TRANSFER_ENCODING, HTTP.CHUNK_CODING);
112 } else if (len >= 0) {
113 response.addHeader(HTTP.CONTENT_LEN, Long.toString(entity.getContentLength()));
114 }
115 // Specify a content type if known
116 if (entity.getContentType() != null && !response.containsHeader(
117 HTTP.CONTENT_TYPE )) {
118 response.addHeader(entity.getContentType());
119 }
120 // Specify a content encoding if known
121 if (entity.getContentEncoding() != null && !response.containsHeader(
122 HTTP.CONTENT_ENCODING)) {
123 response.addHeader(entity.getContentEncoding());
124 }
125 } else {
126 final int status = response.getStatusLine().getStatusCode();
127 if (status != HttpStatus.SC_NO_CONTENT
128 && status != HttpStatus.SC_NOT_MODIFIED
129 && status != HttpStatus.SC_RESET_CONTENT) {
130 response.addHeader(HTTP.CONTENT_LEN, "0");
131 }
132 }
133 }
134
135 }