1 /*
2 * Copyright 2009 Red Hat, Inc.
3 *
4 * Red Hat licenses this file to you under the Apache License, version 2.0
5 * (the "License"); you may not use this file except in compliance with the
6 * License. You may obtain a copy of the License at:
7 *
8 * http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
12 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
13 * License for the specific language governing permissions and limitations
14 * under the License.
15 */
16 package org.jboss.netty.handler.codec.http2;
17
18 import org.jboss.netty.buffer.ChannelBuffer;
19 import org.jboss.netty.channel.ChannelPipeline;
20 import org.jboss.netty.handler.codec.frame.TooLongFrameException;
21
22
23 /**
24 * Decodes {@link ChannelBuffer}s into {@link HttpResponse}s and
25 * {@link HttpChunk}s.
26 *
27 * <h3>Parameters that prevents excessive memory consumption</h3>
28 * <table border="1">
29 * <tr>
30 * <th>Name</th><th>Meaning</th>
31 * </tr>
32 * <tr>
33 * <td>{@code maxInitialLineLength}</td>
34 * <td>The maximum length of the initial line (e.g. {@code "HTTP/1.0 200 OK"})
35 * If the length of the initial line exceeds this value, a
36 * {@link TooLongFrameException} will be raised.</td>
37 * </tr>
38 * <tr>
39 * <td>{@code maxHeaderSize}</td>
40 * <td>The maximum length of all headers. If the sum of the length of each
41 * header exceeds this value, a {@link TooLongFrameException} will be raised.</td>
42 * </tr>
43 * <tr>
44 * <td>{@code maxChunkSize}</td>
45 * <td>The maximum length of the content or each chunk. If the content length
46 * exceeds this value, the transfer encoding of the decoded response will be
47 * converted to 'chunked' and the content will be split into multiple
48 * {@link HttpChunk}s. If the transfer encoding of the HTTP response is
49 * 'chunked' already, each chunk will be split into smaller chunks if the
50 * length of the chunk exceeds this value. If you prefer not to handle
51 * {@link HttpChunk}s in your handler, insert {@link HttpChunkAggregator}
52 * after this decoder in the {@link ChannelPipeline}.</td>
53 * </tr>
54 * </table>
55 *
56 * <h3>Decoding a response for a <tt>HEAD</tt> request</h3>
57 * <p>
58 * Unlike other HTTP requests, the successful response of a <tt>HEAD</tt>
59 * request does not have any content even if there is <tt>Content-Length</tt>
60 * header. Because {@link HttpResponseDecoder} is not able to determine if the
61 * response currently being decoded is associated with a <tt>HEAD</tt> request,
62 * you must override {@link #isContentAlwaysEmpty(HttpMessage)} to return
63 * <tt>true</tt> for the response of the <tt>HEAD</tt> request.
64 * </p><p>
65 * If you are writing an HTTP client that issues a <tt>HEAD</tt> request,
66 * please use {@link HttpClientCodec} instead of this decoder. It will perform
67 * additional state management to handle the responses for <tt>HEAD</tt>
68 * requests correctly.
69 * </p>
70 *
71 * <h3>Decoding a response for a <tt>CONNECT</tt> request</h3>
72 * <p>
73 * You also need to do additional state management to handle the response of a
74 * <tt>CONNECT</tt> request properly, like you did for <tt>HEAD</tt>. One
75 * difference is that the decoder should stop decoding completely after decoding
76 * the successful 200 response since the connection is not an HTTP connection
77 * anymore.
78 * </p><p>
79 * {@link HttpClientCodec} also handles this edge case correctly, so you have to
80 * use {@link HttpClientCodec} if you are writing an HTTP client that issues a
81 * <tt>CONNECT</tt> request.
82 * </p>
83 *
84 * @author <a href="http://www.jboss.org/netty/">The Netty Project</a>
85 * @author Andy Taylor (andy.taylor@jboss.org)
86 * @author <a href="http://gleamynode.net/">Trustin Lee</a>
87 * @version $Rev: 619 $, $Date: 2010-11-11 20:30:06 +0100 (jeu., 11 nov. 2010) $
88 */
89 public class HttpResponseDecoder extends HttpMessageDecoder {
90
91 /**
92 * Creates a new instance with the default
93 * {@code maxInitialLineLength (4096}}, {@code maxHeaderSize (8192)}, and
94 * {@code maxChunkSize (8192)}.
95 */
96 public HttpResponseDecoder() {
97 super();
98 }
99
100 /**
101 * Creates a new instance with the specified parameters.
102 */
103 public HttpResponseDecoder(
104 int maxInitialLineLength, int maxHeaderSize, int maxChunkSize) {
105 super(maxInitialLineLength, maxHeaderSize, maxChunkSize);
106 }
107
108 @Override
109 protected HttpMessage createMessage(String[] initialLine) {
110 return new DefaultHttpResponse(HttpVersion.valueOf(initialLine[0]), new HttpResponseStatus(Integer.valueOf(initialLine[1]), initialLine[2]));
111 }
112
113 @Override
114 protected boolean isDecodingRequest() {
115 return false;
116 }
117 }