/*
* Copyright 2013 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 io.netty.handler.codec.http.websocketx;
import io.netty.buffer.ByteBuf;
import io.netty.buffer.CompositeByteBuf;
import io.netty.channel.ChannelHandlerContext;
import io.netty.handler.codec.MessageToMessageDecoder;
import io.netty.handler.codec.TooLongFrameException;
import java.util.List;
/**
* Handler that aggregate fragmented WebSocketFrame's.
*
* Be aware if PING/PONG/CLOSE frames are send in the middle of a fragmented {@link WebSocketFrame} they will
* just get forwarded to the next handler in the pipeline.
*/
public class WebSocketFrameAggregator extends MessageToMessageDecoder<WebSocketFrame> {
private final int maxFrameSize;
private WebSocketFrame currentFrame;
private boolean tooLongFrameFound;
/**
* Construct a new instance
*
* @param maxFrameSize If the size of the aggregated frame exceeds this value,
* a {@link TooLongFrameException} is thrown.
*/
public WebSocketFrameAggregator(int maxFrameSize) {
if (maxFrameSize < 1) {
throw new IllegalArgumentException("maxFrameSize must be > 0");
}
this.maxFrameSize = maxFrameSize;
}
@Override
protected void decode(ChannelHandlerContext ctx, WebSocketFrame msg, List<Object> out) throws Exception {
if (currentFrame == null) {
tooLongFrameFound = false;
if (msg.isFinalFragment()) {
out.add(msg.retain());
return;
}
ByteBuf buf = ctx.alloc().compositeBuffer().addComponent(msg.content().retain());
buf.writerIndex(buf.writerIndex() + msg.content().readableBytes());
if (msg instanceof TextWebSocketFrame) {
currentFrame = new TextWebSocketFrame(true, msg.rsv(), buf);
} else if (msg instanceof BinaryWebSocketFrame) {
currentFrame = new BinaryWebSocketFrame(true, msg.rsv(), buf);
} else {
buf.release();
throw new IllegalStateException(
"WebSocket frame was not of type TextWebSocketFrame or BinaryWebSocketFrame");
}
return;
}
if (msg instanceof ContinuationWebSocketFrame) {
if (tooLongFrameFound) {
if (msg.isFinalFragment()) {
currentFrame = null;
}
return;
}
CompositeByteBuf content = (CompositeByteBuf) currentFrame.content();
if (content.readableBytes() > maxFrameSize - msg.content().readableBytes()) {
// release the current frame
currentFrame.release();
tooLongFrameFound = true;
throw new TooLongFrameException(
"WebSocketFrame length exceeded " + content +
" bytes.");
}
content.addComponent(msg.content().retain());
content.writerIndex(content.writerIndex() + msg.content().readableBytes());
if (msg.isFinalFragment()) {
WebSocketFrame currentFrame = this.currentFrame;
this.currentFrame = null;
out.add(currentFrame);
return;
} else {
return;
}
}
// It is possible to receive CLOSE/PING/PONG frames during fragmented frames so just pass them to the next
// handler in the chain
out.add(msg.retain());
}
@Override
public void channelInactive(ChannelHandlerContext ctx) throws Exception {
super.channelInactive(ctx);
// release current frame if it is not null as it may be a left-over
if (currentFrame != null) {
currentFrame.release();
currentFrame = null;
}
}
@Override
public void handlerRemoved(ChannelHandlerContext ctx) throws Exception {
super.handlerRemoved(ctx);
// release current frame if it is not null as it may be a left-over as there is not much more we can do in
// this case
if (currentFrame != null) {
currentFrame.release();
currentFrame = null;
}
}
}