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Karry/HttpChunkCache.java

Last active Dec 15, 2015
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Http chunk cache is designed for sharing part of http response (on top of JBoss Netty) that is identical for many clients. Response have to be send as http/1.1 chunks. As key is used Google proto buffer, but it is simple to rewrite to something different.
/**
* <pre>
* Copyright (c) 2013, AVAST Software a.s.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* * Neither the name of the AVAST Software a.s. nor the
* names of its contributors may be used to endorse or promote products
* derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER BE LIABLE FOR ANY
* DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
* </pre>
*
*/
import com.google.protobuf.MessageLite;
import java.nio.ByteBuffer;
import java.nio.ByteOrder;
import java.util.Map;
import org.jboss.netty.buffer.ChannelBuffer;
import org.jboss.netty.buffer.ChannelBuffers;
import org.jboss.netty.util.CharsetUtil;
import org.jboss.netty.util.internal.ConcurrentWeakKeyHashMap;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
/**
* Http chunk cache is designed for sharing part of http response that is
* identical for many clients. Response have to be send as http/1.1 chunks. As
* key is used Google proto buffer, but it is simple to rewrite to something
* different.
*
* @author karry
*/
public class HttpChunkCache {
/**
* Carriage return
*/
static final byte CR = 13;
/**
* Line feed character
*/
static final byte LF = 10;
/**
* carriage return line feed
*/
static final byte[] CRLF = new byte[]{CR, LF};
private static final Logger LOGGER = LoggerFactory.getLogger(HttpChunkCache.class);
private final Map<MessageLite, ByteBuffer> weakMap = new ConcurrentWeakKeyHashMap<MessageLite, ByteBuffer>();
/**
* Create new ByteBuffer with shared direct memory filled from bytes of
* message and packaged into http chunk.
*/
public ByteBuffer get(MessageLite message) {
ByteBuffer directByteBuffer = weakMap.get(message);
if (directByteBuffer != null)
return directByteBuffer.slice(); // create clone with shared memory area
byte[] contentBytes = message.toByteArray();
int contentLength = contentBytes.length;
// create http chunk (this code is copied from org.jboss.netty.handler.codec.http.HttpMessageEncoder)
ChannelBuffer chunkBuffer = ChannelBuffers.wrappedBuffer(
ChannelBuffers.copiedBuffer(
Integer.toHexString(contentLength),
CharsetUtil.US_ASCII),
ChannelBuffers.wrappedBuffer(CRLF),
ChannelBuffers.wrappedBuffer(contentBytes),
ChannelBuffers.wrappedBuffer(CRLF));
// copy buffer to direct buffer - it can be propagate to kernel without copy
int capacity = chunkBuffer.readableBytes();
directByteBuffer = ByteBuffer.allocateDirect(capacity).order(ByteOrder.BIG_ENDIAN);
chunkBuffer.readBytes(directByteBuffer);
directByteBuffer.flip(); // rewind to begining
LOGGER.debug("put into cache " + message.hashCode() + " " + (((double) directByteBuffer.capacity()) / 1024d) + " KiB");
weakMap.put(message, directByteBuffer);
return directByteBuffer.slice(); // create clone with shared memory area
}
}
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