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.hc.core5.http.protocol;
29
30 import java.io.IOException;
31
32 import org.apache.hc.core5.annotation.Contract;
33 import org.apache.hc.core5.annotation.ThreadingBehavior;
34 import org.apache.hc.core5.http.EntityDetails;
35 import org.apache.hc.core5.http.HeaderElements;
36 import org.apache.hc.core5.http.HttpException;
37 import org.apache.hc.core5.http.HttpHeaders;
38 import org.apache.hc.core5.http.HttpResponse;
39 import org.apache.hc.core5.http.HttpResponseInterceptor;
40 import org.apache.hc.core5.http.HttpStatus;
41 import org.apache.hc.core5.http.HttpVersion;
42 import org.apache.hc.core5.http.ProtocolException;
43 import org.apache.hc.core5.http.ProtocolVersion;
44 import org.apache.hc.core5.http.message.MessageSupport;
45 import org.apache.hc.core5.util.Args;
46
47 /**
48 * This response interceptor is responsible for delimiting the message content
49 * by adding {@code Content-Length} or {@code Transfer-Content} headers based
50 * on the properties of the enclosed entity and the protocol version.
51 * <p>
52 * This interceptor is essential for the HTTP protocol conformance and
53 * the correct operation of the server-side message processing pipeline.
54 * </p>
55 *
56 * @since 4.0
57 */
58 @Contract(threading = ThreadingBehavior.IMMUTABLE)
59 public class ResponseContent implements HttpResponseInterceptor {
60
61 public static final ResponseContent INSTANCE = new ResponseContent();
62
63 private final boolean overwrite;
64
65 /**
66 * Default constructor. The {@code Content-Length} or {@code Transfer-Encoding}
67 * will cause the interceptor to throw {@link ProtocolException} if already present in the
68 * response message.
69 */
70 public ResponseContent() {
71 this(false);
72 }
73
74 /**
75 * Constructor that can be used to fine-tune behavior of this interceptor.
76 *
77 * @param overwrite If set to {@code true} the {@code Content-Length} and
78 * {@code Transfer-Encoding} headers will be created or updated if already present.
79 * If set to {@code false} the {@code Content-Length} and
80 * {@code Transfer-Encoding} headers will cause the interceptor to throw
81 * {@link ProtocolException} if already present in the response message.
82 *
83 * @since 4.2
84 */
85 public ResponseContent(final boolean overwrite) {
86 super();
87 this.overwrite = overwrite;
88 }
89
90 /**
91 * Processes the response (possibly updating or inserting) Content-Length and Transfer-Encoding headers.
92 * @param response The HttpResponse to modify.
93 * @param context Unused.
94 * @throws ProtocolException If either the Content-Length or Transfer-Encoding headers are found.
95 * @throws IllegalArgumentException If the response is null.
96 */
97 @Override
98 public void process(final HttpResponse response, final EntityDetails entity, final HttpContext context)
99 throws HttpException, IOException {
100 Args.notNull(response, "HTTP response");
101 if (this.overwrite) {
102 response.removeHeaders(HttpHeaders.TRANSFER_ENCODING);
103 response.removeHeaders(HttpHeaders.CONTENT_LENGTH);
104 } else {
105 if (response.containsHeader(HttpHeaders.TRANSFER_ENCODING)) {
106 throw new ProtocolException("Transfer-encoding header already present");
107 }
108 if (response.containsHeader(HttpHeaders.CONTENT_LENGTH)) {
109 throw new ProtocolException("Content-Length header already present");
110 }
111 }
112 final ProtocolVersion ver = context.getProtocolVersion();
113 if (entity != null) {
114 final long len = entity.getContentLength();
115 if (len >= 0 && !entity.isChunked()) {
116 response.addHeader(HttpHeaders.CONTENT_LENGTH, Long.toString(entity.getContentLength()));
117 } else if (ver.greaterEquals(HttpVersion.HTTP_1_1)) {
118 response.addHeader(HttpHeaders.TRANSFER_ENCODING, HeaderElements.CHUNKED_ENCODING);
119 MessageSupport.addTrailerHeader(response, entity);
120 }
121 MessageSupport.addContentTypeHeader(response, entity);
122 MessageSupport.addContentEncodingHeader(response, entity);
123 } else {
124 final int status = response.getCode();
125 if (status != HttpStatus.SC_NO_CONTENT && status != HttpStatus.SC_NOT_MODIFIED) {
126 response.addHeader(HttpHeaders.CONTENT_LENGTH, "0");
127 }
128 }
129 }
130
131 }