2011-09-26 14:51:15 +02:00
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/*
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2011-12-09 06:18:34 +01:00
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* Copyright 2011 The Netty Project
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2011-09-26 14:51:15 +02:00
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*
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2011-12-09 06:18:34 +01:00
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* The Netty Project licenses this file to you under the Apache License,
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* version 2.0 (the "License"); you may not use this file except in compliance
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* with the License. You may obtain a copy of the License at:
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2011-09-26 14:51:15 +02:00
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*
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2011-12-09 06:18:34 +01:00
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* http://www.apache.org/licenses/LICENSE-2.0
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2011-09-26 14:51:15 +02:00
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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2011-12-09 06:18:34 +01:00
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* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
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2011-09-26 14:51:15 +02:00
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* License for the specific language governing permissions and limitations
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* under the License.
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*/
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2011-12-09 04:38:59 +01:00
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package io.netty.handler.codec.http.websocketx;
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2011-09-26 14:51:15 +02:00
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2011-12-09 04:38:59 +01:00
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import io.netty.buffer.ChannelBuffer;
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import io.netty.channel.Channel;
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import io.netty.channel.ChannelHandlerContext;
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import io.netty.handler.codec.frame.TooLongFrameException;
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import io.netty.handler.codec.replay.ReplayingDecoder;
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import io.netty.handler.codec.replay.VoidEnum;
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2011-09-26 14:51:15 +02:00
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/**
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* Decodes {@link ChannelBuffer}s into {@link WebSocketFrame}s.
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* <p>
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* For the detailed instruction on adding add Web Socket support to your HTTP
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* server, take a look into the <tt>WebSocketServer</tt> example located in the
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2011-12-09 04:38:59 +01:00
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* {@code io.netty.example.http.websocket} package.
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2011-09-26 14:51:15 +02:00
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* @apiviz.landmark
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2011-12-09 04:38:59 +01:00
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* @apiviz.uses io.netty.handler.codec.http.websocket.WebSocketFrame
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2011-09-26 14:51:15 +02:00
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*/
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public class WebSocket00FrameDecoder extends ReplayingDecoder<VoidEnum> {
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2011-11-04 19:28:15 +01:00
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public static final int DEFAULT_MAX_FRAME_SIZE = 16384;
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private final int maxFrameSize;
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private boolean receivedClosingHandshake;
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public WebSocket00FrameDecoder() {
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this(DEFAULT_MAX_FRAME_SIZE);
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}
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/**
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* Creates a new instance of {@code WebSocketFrameDecoder} with the
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* specified {@code maxFrameSize}. If the client sends a frame size larger
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* than {@code maxFrameSize}, the channel will be closed.
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*
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* @param maxFrameSize
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* the maximum frame size to decode
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*/
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public WebSocket00FrameDecoder(int maxFrameSize) {
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this.maxFrameSize = maxFrameSize;
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}
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@Override
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protected Object decode(ChannelHandlerContext ctx, Channel channel, ChannelBuffer buffer, VoidEnum state) throws Exception {
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// Discard all data received if closing handshake was received before.
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if (receivedClosingHandshake) {
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buffer.skipBytes(actualReadableBytes());
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return null;
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}
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// Decode a frame otherwise.
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byte type = buffer.readByte();
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if ((type & 0x80) == 0x80) {
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// If the MSB on type is set, decode the frame length
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return decodeBinaryFrame(type, buffer);
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} else {
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// Decode a 0xff terminated UTF-8 string
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return decodeTextFrame(type, buffer);
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}
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}
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private WebSocketFrame decodeBinaryFrame(byte type, ChannelBuffer buffer) throws TooLongFrameException {
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long frameSize = 0;
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int lengthFieldSize = 0;
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byte b;
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do {
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b = buffer.readByte();
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frameSize <<= 7;
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frameSize |= b & 0x7f;
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if (frameSize > maxFrameSize) {
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throw new TooLongFrameException();
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}
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lengthFieldSize++;
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if (lengthFieldSize > 8) {
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// Perhaps a malicious peer?
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throw new TooLongFrameException();
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}
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} while ((b & 0x80) == 0x80);
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if (type == ((byte) 0xFF) && frameSize == 0) {
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receivedClosingHandshake = true;
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return new CloseWebSocketFrame();
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}
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return new BinaryWebSocketFrame(buffer.readBytes((int) frameSize));
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}
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private WebSocketFrame decodeTextFrame(byte type, ChannelBuffer buffer) throws TooLongFrameException {
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int ridx = buffer.readerIndex();
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int rbytes = actualReadableBytes();
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int delimPos = buffer.indexOf(ridx, ridx + rbytes, (byte) 0xFF);
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if (delimPos == -1) {
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// Frame delimiter (0xFF) not found
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if (rbytes > maxFrameSize) {
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// Frame length exceeded the maximum
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throw new TooLongFrameException();
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} else {
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// Wait until more data is received
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return null;
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}
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}
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int frameSize = delimPos - ridx;
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if (frameSize > maxFrameSize) {
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throw new TooLongFrameException();
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}
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ChannelBuffer binaryData = buffer.readBytes(frameSize);
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buffer.skipBytes(1);
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int ffDelimPos = binaryData.indexOf(binaryData.readerIndex(), binaryData.writerIndex(), (byte) 0xFF);
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if (ffDelimPos >= 0) {
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throw new IllegalArgumentException("a text frame should not contain 0xFF.");
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}
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return new TextWebSocketFrame(binaryData);
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}
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2011-09-26 14:51:15 +02:00
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}
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