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The Netty project is an effort to provide an asynchronous event-driven
network application framework and tools for rapid development of
maintainable high performance and high scalability protocol servers and
clients. In other words, Netty is a NIO client server framework which
enables quick and easy development of network applications such as protocol
servers and clients. It greatly simplifies and streamlines network
programming such as TCP and UDP socket server.
/*
* Copyright 2012 The Netty Project
*
* The Netty Project licenses this file to you under the Apache License,
* version 2.0 (the "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at:
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
* License for the specific language governing permissions and limitations
* under the License.
*/
package org.jboss.netty.handler.codec.rtsp;
import org.jboss.netty.buffer.ChannelBuffer;
import org.jboss.netty.channel.Channel;
import org.jboss.netty.channel.ChannelHandlerContext;
import org.jboss.netty.handler.codec.embedder.DecoderEmbedder;
import org.jboss.netty.handler.codec.frame.TooLongFrameException;
import org.jboss.netty.handler.codec.http.HttpChunkAggregator;
import org.jboss.netty.handler.codec.http.HttpMessage;
import org.jboss.netty.handler.codec.http.HttpMessageDecoder;
/**
* Decodes {@link ChannelBuffer}s into RTSP messages represented in
* {@link HttpMessage}s.
*
*
Parameters that prevents excessive memory consumption
*
*
* Name Meaning
*
*
* {@code maxInitialLineLength}
* The maximum length of the initial line
* (e.g. {@code "SETUP / RTSP/1.0"} or {@code "RTSP/1.0 200 OK"})
* If the length of the initial line exceeds this value, a
* {@link TooLongFrameException} will be raised.
*
*
* {@code maxHeaderSize}
* The maximum length of all headers. If the sum of the length of each
* header exceeds this value, a {@link TooLongFrameException} will be raised.
*
*
* {@code maxContentLength}
* The maximum length of the content. If the content length exceeds this
* value, a {@link TooLongFrameException} will be raised.
*
*
* @apiviz.landmark
*/
public abstract class RtspMessageDecoder extends HttpMessageDecoder {
private final DecoderEmbedder aggregator;
/**
* Creates a new instance with the default
* {@code maxInitialLineLength (4096}}, {@code maxHeaderSize (8192)}, and
* {@code maxContentLength (8192)}.
*/
protected RtspMessageDecoder() {
this(4096, 8192, 8192);
}
/**
* Creates a new instance with the specified parameters.
*/
protected RtspMessageDecoder(int maxInitialLineLength, int maxHeaderSize, int maxContentLength) {
super(maxInitialLineLength, maxHeaderSize, maxContentLength * 2);
aggregator = new DecoderEmbedder(new HttpChunkAggregator(maxContentLength));
}
@Override
protected Object decode(ChannelHandlerContext ctx, Channel channel,
ChannelBuffer buffer, State state) throws Exception {
Object o = super.decode(ctx, channel, buffer, state);
if (o != null && aggregator.offer(o)) {
return aggregator.poll();
} else {
return null;
}
}
@Override
protected boolean isContentAlwaysEmpty(HttpMessage msg) {
// Unlike HTTP, RTSP always assumes zero-length body if Content-Length
// header is absent.
boolean empty = super.isContentAlwaysEmpty(msg);
if (empty) {
return true;
}
if (!msg.headers().contains(RtspHeaders.Names.CONTENT_LENGTH)) {
return true;
}
return empty;
}
}