1 /*
2 * Copyright 2012 The Netty Project
3 *
4 * The Netty Project licenses this file to you under the Apache License,
5 * version 2.0 (the "License"); you may not use this file except in compliance
6 * with the License. You may obtain a copy of the License at:
7 *
8 * https://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 io.netty5.handler.codec.http;
17
18 import io.netty5.channel.ChannelHandlerContext;
19 import io.netty5.channel.ChannelPipeline;
20
21 /**
22 * Decodes {@link io.netty5.buffer.api.Buffer}s into {@link HttpResponse}s and {@link HttpContent}s.
23 *
24 * <h3>Parameters that prevents excessive memory consumption</h3>
25 * <table border="1">
26 * <tr>
27 * <th>Name</th><th>Meaning</th>
28 * </tr>
29 * <tr>
30 * <td>{@code maxInitialLineLength}</td>
31 * <td>The maximum length of the initial line (e.g. {@code "HTTP/1.0 200 OK"})
32 * If the length of the initial line exceeds this value, a
33 * {@link TooLongHttpLineException} will be raised.</td>
34 * </tr>
35 * <tr>
36 * <td>{@code maxHeaderSize}</td>
37 * <td>The maximum length of all headers. If the sum of the length of each
38 * header exceeds this value, a {@link TooLongHttpHeaderException} will be raised.</td>
39 * </tr>
40 * <tr>
41 * <td>{@code maxChunkSize}</td>
42 * <td>The maximum length of the content or each chunk. If the content length
43 * exceeds this value, the transfer encoding of the decoded response will be
44 * converted to 'chunked' and the content will be split into multiple
45 * {@link HttpContent}s. If the transfer encoding of the HTTP response is
46 * 'chunked' already, each chunk will be split into smaller chunks if the
47 * length of the chunk exceeds this value. If you prefer not to handle
48 * {@link HttpContent}s in your handler, insert {@link HttpObjectAggregator}
49 * after this decoder in the {@link ChannelPipeline}.</td>
50 * </tr>
51 * </table>
52 *
53 * <h3>Decoding a response for a <tt>HEAD</tt> request</h3>
54 * <p>
55 * Unlike other HTTP requests, the successful response of a <tt>HEAD</tt>
56 * request does not have any content even if there is <tt>Content-Length</tt>
57 * header. Because {@link HttpResponseDecoder} is not able to determine if the
58 * response currently being decoded is associated with a <tt>HEAD</tt> request,
59 * you must override {@link #isContentAlwaysEmpty(HttpMessage)} to return
60 * <tt>true</tt> for the response of the <tt>HEAD</tt> request.
61 * </p><p>
62 * If you are writing an HTTP client that issues a <tt>HEAD</tt> request,
63 * please use {@link HttpClientCodec} instead of this decoder. It will perform
64 * additional state management to handle the responses for <tt>HEAD</tt>
65 * requests correctly.
66 * </p>
67 *
68 * <h3>Decoding a response for a <tt>CONNECT</tt> request</h3>
69 * <p>
70 * You also need to do additional state management to handle the response of a
71 * <tt>CONNECT</tt> request properly, like you did for <tt>HEAD</tt>. One
72 * difference is that the decoder should stop decoding completely after decoding
73 * the successful 200 response since the connection is not an HTTP connection
74 * anymore.
75 * </p><p>
76 * {@link HttpClientCodec} also handles this edge case correctly, so you have to
77 * use {@link HttpClientCodec} if you are writing an HTTP client that issues a
78 * <tt>CONNECT</tt> request.
79 * </p>
80 */
81 public class HttpResponseDecoder extends HttpObjectDecoder {
82
83 private static final HttpResponseStatus UNKNOWN_STATUS = new HttpResponseStatus(999, "Unknown");
84
85 /**
86 * Creates a new instance with the default
87 * {@code maxInitialLineLength (4096)}, {@code maxHeaderSize (8192)}, and
88 * {@code maxChunkSize (8192)}.
89 */
90 public HttpResponseDecoder() {
91 }
92
93 /**
94 * Creates a new instance with the specified parameters.
95 */
96 public HttpResponseDecoder(
97 int maxInitialLineLength, int maxHeaderSize) {
98 super(maxInitialLineLength, maxHeaderSize, DEFAULT_CHUNKED_SUPPORTED);
99 }
100
101 public HttpResponseDecoder(
102 int maxInitialLineLength, int maxHeaderSize, boolean validateHeaders) {
103 super(maxInitialLineLength, maxHeaderSize, DEFAULT_CHUNKED_SUPPORTED, validateHeaders);
104 }
105
106 public HttpResponseDecoder(
107 int maxInitialLineLength, int maxHeaderSize, boolean validateHeaders,
108 int initialBufferSize) {
109 super(maxInitialLineLength, maxHeaderSize, DEFAULT_CHUNKED_SUPPORTED, validateHeaders, initialBufferSize);
110 }
111
112 public HttpResponseDecoder(
113 int maxInitialLineLength, int maxHeaderSize, boolean validateHeaders,
114 int initialBufferSize, boolean allowDuplicateContentLengths) {
115 super(maxInitialLineLength, maxHeaderSize, DEFAULT_CHUNKED_SUPPORTED, validateHeaders,
116 initialBufferSize, allowDuplicateContentLengths);
117 }
118
119 @Override
120 protected HttpMessage createMessage(String[] initialLine) {
121 return new DefaultHttpResponse(
122 HttpVersion.valueOf(initialLine[0]),
123 HttpResponseStatus.valueOf(Integer.parseInt(initialLine[1]), initialLine[2]), validateHeaders);
124 }
125
126 @Override
127 protected HttpMessage createInvalidMessage(ChannelHandlerContext ctx) {
128 return new DefaultFullHttpResponse(HttpVersion.HTTP_1_0, UNKNOWN_STATUS, ctx.bufferAllocator().allocate(0),
129 validateHeaders);
130 }
131
132 @Override
133 protected boolean isDecodingRequest() {
134 return false;
135 }
136 }