1 /*
2 * Copyright 2015 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.rtsp;
17
18 import io.netty5.channel.ChannelHandlerContext;
19 import io.netty5.handler.codec.http.DefaultFullHttpRequest;
20 import io.netty5.handler.codec.http.DefaultFullHttpResponse;
21 import io.netty5.handler.codec.http.DefaultHttpRequest;
22 import io.netty5.handler.codec.http.DefaultHttpResponse;
23 import io.netty5.handler.codec.http.HttpMessage;
24 import io.netty5.handler.codec.http.HttpObjectDecoder;
25 import io.netty5.handler.codec.http.HttpResponseStatus;
26
27 import java.util.regex.Pattern;
28
29 /**
30 * Decodes {@link io.netty5.buffer.ByteBuf}s into RTSP messages represented in
31 * {@link HttpMessage}s.
32 * <p>
33 * <h3>Parameters that prevents excessive memory consumption</h3>
34 * <table border="1">
35 * <tr>
36 * <th>Name</th><th>Meaning</th>
37 * </tr>
38 * <tr>
39 * <td>{@code maxInitialLineLength}</td>
40 * <td>The maximum length of the initial line
41 * (e.g. {@code "SETUP / RTSP/1.0"} or {@code "RTSP/1.0 200 OK"})
42 * If the length of the initial line exceeds this value, a
43 * {@link io.netty5.handler.codec.TooLongFrameException} will be raised.</td>
44 * </tr>
45 * <tr>
46 * <td>{@code maxHeaderSize}</td>
47 * <td>The maximum length of all headers. If the sum of the length of each
48 * header exceeds this value, a {@link io.netty5.handler.codec.TooLongFrameException} will be
49 * raised.</td>
50 * </tr>
51 * <tr>
52 * <td>{@code maxContentLength}</td>
53 * <td>The maximum length of the content. If the content length exceeds this
54 * value, a {@link io.netty5.handler.codec.TooLongFrameException} will be raised.</td>
55 * </tr>
56 * </table>
57 */
58 public class RtspDecoder extends HttpObjectDecoder {
59 /**
60 * Status code for unknown responses.
61 */
62 private static final HttpResponseStatus UNKNOWN_STATUS =
63 new HttpResponseStatus(999, "Unknown");
64 /**
65 * True if the message to decode is a request.
66 * False if the message to decode is a response.
67 */
68 private boolean isDecodingRequest;
69
70 /**
71 * Regex used on first line in message to detect if it is a response.
72 */
73 private static final Pattern versionPattern = Pattern.compile("RTSP/\\d\\.\\d");
74
75 /**
76 * Constant for default max content length.
77 */
78 public static final int DEFAULT_MAX_CONTENT_LENGTH = 8192;
79
80 /**
81 * Creates a new instance with the default
82 * {@code maxInitialLineLength (4096)}, {@code maxHeaderSize (8192)}, and
83 * {@code maxContentLength (8192)}.
84 */
85 public RtspDecoder() {
86 this(DEFAULT_MAX_INITIAL_LINE_LENGTH,
87 DEFAULT_MAX_HEADER_SIZE,
88 DEFAULT_MAX_CONTENT_LENGTH);
89 }
90
91 /**
92 * Creates a new instance with the specified parameters.
93 * @param maxInitialLineLength The max allowed length of initial line
94 * @param maxHeaderSize The max allowed size of header
95 * @param maxContentLength The max allowed content length
96 */
97 public RtspDecoder(final int maxInitialLineLength,
98 final int maxHeaderSize,
99 final int maxContentLength) {
100 super(maxInitialLineLength, maxHeaderSize, false);
101 }
102
103 /**
104 * Creates a new instance with the specified parameters.
105 * @param maxInitialLineLength The max allowed length of initial line
106 * @param maxHeaderSize The max allowed size of header
107 * @param maxContentLength The max allowed content length
108 * @param validateHeaders Set to true if headers should be validated
109 */
110 public RtspDecoder(final int maxInitialLineLength,
111 final int maxHeaderSize,
112 final int maxContentLength,
113 final boolean validateHeaders) {
114 super(maxInitialLineLength,
115 maxHeaderSize,
116 false,
117 validateHeaders);
118 }
119
120 @Override
121 protected HttpMessage createMessage(final String[] initialLine)
122 throws Exception {
123 // If the first element of the initial line is a version string then
124 // this is a response
125 if (versionPattern.matcher(initialLine[0]).matches()) {
126 isDecodingRequest = false;
127 return new DefaultHttpResponse(RtspVersions.valueOf(initialLine[0]),
128 new HttpResponseStatus(Integer.parseInt(initialLine[1]),
129 initialLine[2]),
130 validateHeaders);
131 } else {
132 isDecodingRequest = true;
133 return new DefaultHttpRequest(RtspVersions.valueOf(initialLine[2]),
134 RtspMethods.valueOf(initialLine[0]),
135 initialLine[1],
136 validateHeaders);
137 }
138 }
139
140 @Override
141 protected boolean isContentAlwaysEmpty(final HttpMessage msg) {
142 // Unlike HTTP, RTSP always assumes zero-length body if Content-Length
143 // header is absent.
144 return super.isContentAlwaysEmpty(msg) || !msg.headers().contains(RtspHeaderNames.CONTENT_LENGTH);
145 }
146
147 @Override
148 protected HttpMessage createInvalidMessage(ChannelHandlerContext ctx) {
149 if (isDecodingRequest) {
150 return new DefaultFullHttpRequest(RtspVersions.RTSP_1_0, RtspMethods.OPTIONS, "/bad-request",
151 ctx.bufferAllocator().allocate(0), validateHeaders);
152 } else {
153 return new DefaultFullHttpResponse(RtspVersions.RTSP_1_0, UNKNOWN_STATUS,
154 ctx.bufferAllocator().allocate(0), validateHeaders);
155 }
156 }
157
158 @Override
159 protected boolean isDecodingRequest() {
160 return isDecodingRequest;
161 }
162 }