1/*
2 * $HeadURL: http://svn.apache.org/repos/asf/httpcomponents/httpcore/trunk/module-main/src/main/java/org/apache/http/protocol/ResponseContent.java $
3 * $Revision: 573864 $
4 * $Date: 2007-09-08 08:53:25 -0700 (Sat, 08 Sep 2007) $
5 *
6 * ====================================================================
7 * Licensed to the Apache Software Foundation (ASF) under one
8 * or more contributor license agreements.  See the NOTICE file
9 * distributed with this work for additional information
10 * regarding copyright ownership.  The ASF licenses this file
11 * to you under the Apache License, Version 2.0 (the
12 * "License"); you may not use this file except in compliance
13 * with the License.  You may obtain a copy of the License at
14 *
15 *   http://www.apache.org/licenses/LICENSE-2.0
16 *
17 * Unless required by applicable law or agreed to in writing,
18 * software distributed under the License is distributed on an
19 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
20 * KIND, either express or implied.  See the License for the
21 * specific language governing permissions and limitations
22 * under the License.
23 * ====================================================================
24 *
25 * This software consists of voluntary contributions made by many
26 * individuals on behalf of the Apache Software Foundation.  For more
27 * information on the Apache Software Foundation, please see
28 * <http://www.apache.org/>.
29 *
30 */
31
32package org.apache.http.protocol;
33
34import java.io.IOException;
35
36import org.apache.http.HttpEntity;
37import org.apache.http.HttpException;
38import org.apache.http.HttpResponse;
39import org.apache.http.HttpResponseInterceptor;
40import org.apache.http.HttpStatus;
41import org.apache.http.HttpVersion;
42import org.apache.http.ProtocolVersion;
43import org.apache.http.ProtocolException;
44
45/**
46 * A response interceptor that sets up entity-related headers.
47 * For use on the server side.
48 *
49 * @author <a href="mailto:oleg at ural.ru">Oleg Kalnichevski</a>
50 *
51 * @version $Revision: 573864 $
52 *
53 * @since 4.0
54 */
55public class ResponseContent implements HttpResponseInterceptor {
56
57    public ResponseContent() {
58        super();
59    }
60
61    public void process(final HttpResponse response, final HttpContext context)
62            throws HttpException, IOException {
63        if (response == null) {
64            throw new IllegalArgumentException("HTTP request may not be null");
65        }
66        if (response.containsHeader(HTTP.TRANSFER_ENCODING)) {
67            throw new ProtocolException("Transfer-encoding header already present");
68        }
69        if (response.containsHeader(HTTP.CONTENT_LEN)) {
70            throw new ProtocolException("Content-Length header already present");
71        }
72        ProtocolVersion ver = response.getStatusLine().getProtocolVersion();
73        HttpEntity entity = response.getEntity();
74        if (entity != null) {
75            long len = entity.getContentLength();
76            if (entity.isChunked() && !ver.lessEquals(HttpVersion.HTTP_1_0)) {
77                response.addHeader(HTTP.TRANSFER_ENCODING, HTTP.CHUNK_CODING);
78            } else if (len >= 0) {
79                response.addHeader(HTTP.CONTENT_LEN, Long.toString(entity.getContentLength()));
80            }
81            // Specify a content type if known
82            if (entity.getContentType() != null && !response.containsHeader(
83                    HTTP.CONTENT_TYPE )) {
84                response.addHeader(entity.getContentType());
85            }
86            // Specify a content encoding if known
87            if (entity.getContentEncoding() != null && !response.containsHeader(
88                    HTTP.CONTENT_ENCODING)) {
89                response.addHeader(entity.getContentEncoding());
90            }
91        } else {
92            int status = response.getStatusLine().getStatusCode();
93            if (status != HttpStatus.SC_NO_CONTENT
94                    && status != HttpStatus.SC_NOT_MODIFIED
95                    && status != HttpStatus.SC_RESET_CONTENT) {
96                response.addHeader(HTTP.CONTENT_LEN, "0");
97            }
98        }
99    }
100
101}
102