[#4212] Backport WebSocket Extension handlers for client and server.

Motivation:

We have websocket extension support (with compression) in old master. We should port this to 4.1

Modifications:

Backport relevant code.

Result:

websocket extension support (with compression) is now in 4.1.

codec-http/src/main/java/io/netty/handler/codec/http/websocketx/TextWebSocketFrame.java

@@ -20,7 +20,7 @@ import io.netty.buffer.Unpooled;
 import io.netty.util.CharsetUtil;
 
 /**
- * Web Socket text frame with assumed UTF-8 encoding
+ * Web Socket text frame
  */
 public class TextWebSocketFrame extends WebSocketFrame {
 
@@ -45,7 +45,7 @@ public class TextWebSocketFrame extends WebSocketFrame {
      * Creates a new text frame with the specified binary data. The final fragment flag is set to true.
      *
      * @param binaryData
-     *            the content of the frame. Must be UTF-8 encoded
+     *            the content of the frame.
      */
     public TextWebSocketFrame(ByteBuf binaryData) {
         super(binaryData);
@@ -81,7 +81,7 @@ public class TextWebSocketFrame extends WebSocketFrame {
      * @param rsv
      *            reserved bits used for protocol extensions
      * @param binaryData
-     *            the content of the frame. Must be UTF-8 encoded
+     *            the content of the frame.
      */
     public TextWebSocketFrame(boolean finalFragment, int rsv, ByteBuf binaryData) {
         super(finalFragment, rsv, binaryData);

codec-http/src/main/java/io/netty/handler/codec/http/websocketx/Utf8FrameValidator.java

@@ -0,0 +1,103 @@
+/*
+ * Copyright 2014 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.Unpooled;
+import io.netty.channel.ChannelFutureListener;
+import io.netty.channel.ChannelHandlerAdapter;
+import io.netty.channel.ChannelHandlerContext;
+import io.netty.channel.ChannelInboundHandlerAdapter;
+import io.netty.handler.codec.ByteToMessageDecoder;
+import io.netty.handler.codec.CorruptedFrameException;
+import io.netty.handler.codec.TooLongFrameException;
+import io.netty.handler.codec.http.websocketx.WebSocket08FrameDecoder.State;
+import io.netty.util.internal.logging.InternalLogger;
+import io.netty.util.internal.logging.InternalLoggerFactory;
+
+import java.util.List;
+
+import static io.netty.buffer.ByteBufUtil.readBytes;
+
+/**
+ *
+ */
+public class Utf8FrameValidator extends ChannelInboundHandlerAdapter {
+
+    private int fragmentedFramesCount;
+    private Utf8Validator utf8Validator;
+
+    @Override
+    public void channelRead(ChannelHandlerContext ctx, Object msg) throws Exception {
+        if (msg instanceof WebSocketFrame) {
+            WebSocketFrame frame = (WebSocketFrame) msg;
+
+            // Processing for possible fragmented messages for text and binary
+            // frames
+            if (((WebSocketFrame) msg).isFinalFragment()) {
+                // Final frame of the sequence. Apparently ping frames are
+                // allowed in the middle of a fragmented message
+                if (!(frame instanceof PingWebSocketFrame)) {
+                    fragmentedFramesCount = 0;
+
+                    // Check text for UTF8 correctness
+                    if ((frame instanceof TextWebSocketFrame) ||
+                            (utf8Validator != null && utf8Validator.isChecking())) {
+                        // Check UTF-8 correctness for this payload
+                        checkUTF8String(ctx, frame.content());
+
+                        // This does a second check to make sure UTF-8
+                        // correctness for entire text message
+                        utf8Validator.finish();
+                    }
+                }
+            } else {
+                // Not final frame so we can expect more frames in the
+                // fragmented sequence
+                if (fragmentedFramesCount == 0) {
+                    // First text or binary frame for a fragmented set
+                    if (frame instanceof TextWebSocketFrame) {
+                        checkUTF8String(ctx, frame.content());
+                    }
+                } else {
+                    // Subsequent frames - only check if init frame is text
+                    if (utf8Validator != null && utf8Validator.isChecking()) {
+                        checkUTF8String(ctx, frame.content());
+                    }
+                }
+
+                // Increment counter
+                fragmentedFramesCount++;
+            }
+        }
+
+        super.channelRead(ctx, msg);
+    }
+
+    private void checkUTF8String(ChannelHandlerContext ctx, ByteBuf buffer) {
+        try {
+            if (utf8Validator == null) {
+                utf8Validator = new Utf8Validator();
+            }
+            utf8Validator.check(buffer);
+        } catch (CorruptedFrameException ex) {
+            if (ctx.channel().isActive()) {
+                ctx.writeAndFlush(Unpooled.EMPTY_BUFFER).addListener(ChannelFutureListener.CLOSE);
+            }
+        }
+    }
+
+}

codec-http/src/main/java/io/netty/handler/codec/http/websocketx/WebSocket08FrameDecoder.java

@@ -107,7 +107,6 @@ public class WebSocket08FrameDecoder extends ByteToMessageDecoder
     private byte[] maskingKey;
     private int framePayloadLen1;
     private boolean receivedClosingHandshake;
-    private Utf8Validator utf8Validator;
     private State state = State.READING_FIRST;
 
     /**
@@ -340,33 +339,8 @@ public class WebSocket08FrameDecoder extends ByteToMessageDecoder
                             // allowed in the middle of a fragmented message
                             if (frameOpcode != OPCODE_PING) {
                                 fragmentedFramesCount = 0;
-
-                                // Check text for UTF8 correctness
-                                if (frameOpcode == OPCODE_TEXT ||
-                                        utf8Validator != null && utf8Validator.isChecking()) {
-                                    // Check UTF-8 correctness for this payload
-                                    checkUTF8String(ctx, payloadBuffer);
-
-                                    // This does a second check to make sure UTF-8
-                                    // correctness for entire text message
-                                    utf8Validator.finish();
-                                }
                             }
                         } else {
-                            // Not final frame so we can expect more frames in the
-                            // fragmented sequence
-                            if (fragmentedFramesCount == 0) {
-                                // First text or binary frame for a fragmented set
-                                if (frameOpcode == OPCODE_TEXT) {
-                                    checkUTF8String(ctx, payloadBuffer);
-                                }
-                            } else {
-                                // Subsequent frames - only check if init frame is text
-                                if (utf8Validator != null && utf8Validator.isChecking()) {
-                                    checkUTF8String(ctx, payloadBuffer);
-                                }
-                            }
-
                             // Increment counter
                             fragmentedFramesCount++;
                         }
@@ -460,17 +434,6 @@ public class WebSocket08FrameDecoder extends ByteToMessageDecoder
         }
     }
 
-    private void checkUTF8String(ChannelHandlerContext ctx, ByteBuf buffer) {
-        try {
-            if (utf8Validator == null) {
-                utf8Validator = new Utf8Validator();
-            }
-            utf8Validator.check(buffer);
-        } catch (CorruptedFrameException ex) {
-            protocolViolation(ctx, ex);
-        }
-    }
-
     /** */
     protected void checkCloseFrameBody(
             ChannelHandlerContext ctx, ByteBuf buffer) {

codec-http/src/main/java/io/netty/handler/codec/http/websocketx/WebSocketClientProtocolHandler.java

@@ -183,5 +183,10 @@ public class WebSocketClientProtocolHandler extends WebSocketProtocolHandler {
             ctx.pipeline().addBefore(ctx.name(), WebSocketClientProtocolHandshakeHandler.class.getName(),
                     new WebSocketClientProtocolHandshakeHandler(handshaker));
         }
+        if (cp.get(Utf8FrameValidator.class) == null) {
+            // Add the UFT8 checking before this one.
+            ctx.pipeline().addBefore(ctx.name(), Utf8FrameValidator.class.getName(),
+                    new Utf8FrameValidator());
+        }
     }
 }

codec-http/src/main/java/io/netty/handler/codec/http/websocketx/WebSocketServerProtocolHandler.java

@@ -105,6 +105,11 @@ public class WebSocketServerProtocolHandler extends WebSocketProtocolHandler {
                     new WebSocketServerProtocolHandshakeHandler(websocketPath, subprotocols,
                             allowExtensions, maxFramePayloadLength, allowMaskMismatch));
         }
+        if (cp.get(Utf8FrameValidator.class) == null) {
+            // Add the UFT8 checking before this one.
+            ctx.pipeline().addBefore(ctx.name(), Utf8FrameValidator.class.getName(),
+                    new Utf8FrameValidator());
+        }
     }
 
     @Override

codec-http/src/main/java/io/netty/handler/codec/http/websocketx/extensions/WebSocketClientExtension.java

@@ -0,0 +1,23 @@
+/*
+ * Copyright 2014 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.extensions;
+
+/**
+ * Created once the handshake phase is done.
+ */
+public interface WebSocketClientExtension extends WebSocketExtension {
+
+}

codec-http/src/main/java/io/netty/handler/codec/http/websocketx/extensions/WebSocketClientExtensionHandler.java

@@ -0,0 +1,131 @@
+/*
+ * Copyright 2014 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.extensions;
+
+import io.netty.channel.ChannelDuplexHandler;
+import io.netty.channel.ChannelHandlerContext;
+import io.netty.channel.ChannelPromise;
+import io.netty.handler.codec.CodecException;
+import io.netty.handler.codec.http.HttpHeaderNames;
+import io.netty.handler.codec.http.HttpRequest;
+import io.netty.handler.codec.http.HttpResponse;
+
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Iterator;
+import java.util.List;
+
+/**
+ * This handler negotiates and initializes the WebSocket Extensions.
+ *
+ * This implementation negotiates the extension with the server in a defined order,
+ * ensures that the successfully negotiated extensions are consistent between them,
+ * and initializes the channel pipeline with the extension decoder and encoder.
+ *
+ * Find a basic implementation for compression extensions at
+ * <tt>io.netty.handler.codec.http.websocketx.extensions.compression.WebSocketClientCompressionHandler</tt>.
+ */
+public class WebSocketClientExtensionHandler extends ChannelDuplexHandler {
+
+    private final List<WebSocketClientExtensionHandshaker> extensionHandshakers;
+
+    /**
+     * Constructor
+     *
+     * @param extensionHandshakers
+     *      The extension handshaker in priority order. A handshaker could be repeated many times
+     *      with fallback configuration.
+     */
+    public WebSocketClientExtensionHandler(WebSocketClientExtensionHandshaker... extensionHandshakers) {
+        if (extensionHandshakers == null) {
+            throw new NullPointerException("extensionHandshakers");
+        }
+        if (extensionHandshakers.length == 0) {
+            throw new IllegalArgumentException("extensionHandshakers must contains at least one handshaker");
+        }
+        this.extensionHandshakers = Arrays.asList(extensionHandshakers);
+    }
+
+    @Override
+    public void write(final ChannelHandlerContext ctx, Object msg, ChannelPromise promise) throws Exception {
+        if (msg instanceof HttpRequest && WebSocketExtensionUtil.isWebsocketUpgrade((HttpRequest) msg)) {
+            HttpRequest request = (HttpRequest) msg;
+            String headerValue = request.headers().getAsString(HttpHeaderNames.SEC_WEBSOCKET_EXTENSIONS);
+
+            for (WebSocketClientExtensionHandshaker extentionHandshaker : extensionHandshakers) {
+                WebSocketExtensionData extensionData = extentionHandshaker.newRequestData();
+                headerValue = WebSocketExtensionUtil.appendExtension(headerValue,
+                        extensionData.name(), extensionData.parameters());
+            }
+
+            request.headers().set(HttpHeaderNames.SEC_WEBSOCKET_EXTENSIONS, headerValue);
+        }
+
+        super.write(ctx, msg, promise);
+    }
+
+    @Override
+    public void channelRead(ChannelHandlerContext ctx, Object msg)
+            throws Exception {
+        if (msg instanceof HttpResponse) {
+            HttpResponse response = (HttpResponse) msg;
+
+            if (WebSocketExtensionUtil.isWebsocketUpgrade(response)) {
+                String extensionsHeader = response.headers().getAsString(HttpHeaderNames.SEC_WEBSOCKET_EXTENSIONS);
+
+                if (extensionsHeader != null) {
+                    List<WebSocketExtensionData> extensions =
+                            WebSocketExtensionUtil.extractExtensions(extensionsHeader);
+                    List<WebSocketClientExtension> validExtensions =
+                            new ArrayList<WebSocketClientExtension>(extensions.size());
+                    int rsv = 0;
+
+                    for (WebSocketExtensionData extensionData : extensions) {
+                        Iterator<WebSocketClientExtensionHandshaker> extensionHandshakersIterator =
+                                extensionHandshakers.iterator();
+                        WebSocketClientExtension validExtension = null;
+
+                        while (validExtension == null && extensionHandshakersIterator.hasNext()) {
+                            WebSocketClientExtensionHandshaker extensionHandshaker =
+                                    extensionHandshakersIterator.next();
+                            validExtension = extensionHandshaker.handshakeExtension(extensionData);
+                        }
+
+                        if (validExtension != null && ((validExtension.rsv() & rsv) == 0)) {
+                            rsv = rsv | validExtension.rsv();
+                            validExtensions.add(validExtension);
+                        } else {
+                            throw new CodecException(
+                                    "invalid WebSocket Extension handhshake for \"" + extensionsHeader + "\"");
+                        }
+                    }
+
+                    for (WebSocketClientExtension validExtension : validExtensions) {
+                        WebSocketExtensionDecoder decoder = validExtension.newExtensionDecoder();
+                        WebSocketExtensionEncoder encoder = validExtension.newExtensionEncoder();
+                        ctx.pipeline().addAfter(ctx.name(), decoder.getClass().getName(), decoder);
+                        ctx.pipeline().addAfter(ctx.name(), encoder.getClass().getName(), encoder);
+                    }
+                }
+
+                ctx.pipeline().remove(ctx.name());
+            }
+        }
+
+        super.channelRead(ctx, msg);
+    }
+}
+

codec-http/src/main/java/io/netty/handler/codec/http/websocketx/extensions/WebSocketClientExtensionHandshaker.java

@@ -0,0 +1,41 @@
+/*
+ * Copyright 2014 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.extensions;
+
+
+/**
+ * Handshakes a client extension with the server.
+ */
+public interface WebSocketClientExtensionHandshaker {
+
+    /**
+     * Return extension configuration to submit to the server.
+     *
+     * @return the desired extension configuration.
+     */
+    WebSocketExtensionData newRequestData();
+
+    /**
+     * Handshake based on server response. It should always succeed because server response
+     * should be a request acknowledge.
+     *
+     * @param extensionData
+     *          the extension configuration sent by the server.
+     * @return an initialized extension if handshake phase succeed or null if failed.
+     */
+    WebSocketClientExtension handshakeExtension(WebSocketExtensionData extensionData);
+
+}

codec-http/src/main/java/io/netty/handler/codec/http/websocketx/extensions/WebSocketExtension.java

@@ -0,0 +1,42 @@
+/*
+ * Copyright 2014 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.extensions;
+
+/**
+ * Created once the handshake phase is done.
+ */
+public interface WebSocketExtension {
+
+    int RSV1 = 0x04;
+    int RSV2 = 0x02;
+    int RSV3 = 0x01;
+
+    /**
+     * @return the reserved bit value to ensure that no other extension should interfere.
+     */
+    int rsv();
+
+    /**
+     * @return create the extension encoder.
+     */
+    WebSocketExtensionEncoder newExtensionEncoder();
+
+    /**
+     * @return create the extension decoder.
+     */
+    WebSocketExtensionDecoder newExtensionDecoder();
+
+}

codec-http/src/main/java/io/netty/handler/codec/http/websocketx/extensions/WebSocketExtensionData.java

@@ -0,0 +1,55 @@
+/*
+ * Copyright 2014 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.extensions;
+
+import java.util.Collections;
+import java.util.Map;
+
+/**
+ * A WebSocket Extension data from the <tt>Sec-WebSocket-Extensions</tt> header.
+ *
+ * See <tt>io.netty.handler.codec.http.HttpHeaders.Names.SEC_WEBSOCKET_EXTENSIONS</tt>.
+ */
+public final class WebSocketExtensionData {
+
+    private final String name;
+    private final Map<String, String> parameters;
+
+    public WebSocketExtensionData(String name, Map<String, String> parameters) {
+        if (name == null) {
+            throw new NullPointerException("name");
+        }
+        if (parameters == null) {
+            throw new NullPointerException("parameters");
+        }
+        this.name = name;
+        this.parameters = Collections.unmodifiableMap(parameters);
+    }
+
+    /**
+     * @return the extension name.
+     */
+    public String name() {
+        return name;
+    }
+
+    /**
+     * @return the extension optional parameters.
+     */
+    public Map<String, String> parameters() {
+        return parameters;
+    }
+}

codec-http/src/main/java/io/netty/handler/codec/http/websocketx/extensions/WebSocketExtensionDecoder.java

@@ -0,0 +1,26 @@
+/*
+ * Copyright 2014 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.extensions;
+
+import io.netty.handler.codec.MessageToMessageDecoder;
+import io.netty.handler.codec.http.websocketx.WebSocketFrame;
+
+/**
+ * Convenient class for <tt>io.netty.handler.codec.http.websocketx.extensions.WebSocketExtension</tt> decoder.
+ */
+public abstract class WebSocketExtensionDecoder extends MessageToMessageDecoder<WebSocketFrame> {
+
+}

codec-http/src/main/java/io/netty/handler/codec/http/websocketx/extensions/WebSocketExtensionEncoder.java

@@ -0,0 +1,26 @@
+/*
+ * Copyright 2014 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.extensions;
+
+import io.netty.handler.codec.MessageToMessageEncoder;
+import io.netty.handler.codec.http.websocketx.WebSocketFrame;
+
+/**
+ * Convenient class for <tt>io.netty.handler.codec.http.websocketx.extensions.WebSocketExtension</tt> encoder.
+ */
+public abstract class WebSocketExtensionEncoder extends MessageToMessageEncoder<WebSocketFrame> {
+
+}

codec-http/src/main/java/io/netty/handler/codec/http/websocketx/extensions/WebSocketExtensionUtil.java

@@ -0,0 +1,106 @@
+/*
+ * Copyright 2014 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.extensions;
+
+import io.netty.handler.codec.http.HttpHeaderNames;
+import io.netty.handler.codec.http.HttpHeaderValues;
+import io.netty.handler.codec.http.HttpHeaders;
+import io.netty.handler.codec.http.HttpMessage;
+import io.netty.util.internal.StringUtil;
+
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.Map.Entry;
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
+
+public final class WebSocketExtensionUtil {
+
+    private static final char EXTENSION_SEPARATOR = ',';
+    private static final char PARAMETER_SEPARATOR = ';';
+    private static final char PARAMETER_EQUAL = '=';
+
+    private static final Pattern PARAMETER = Pattern.compile("^([^=]+)(=[\\\"]?([^\\\"]+)[\\\"]?)?$");
+
+    static boolean isWebsocketUpgrade(HttpMessage httpMessage) {
+        if (httpMessage == null) {
+            throw new NullPointerException("httpMessage");
+        }
+        return httpMessage.headers().contains(HttpHeaderNames.CONNECTION, HttpHeaderValues.UPGRADE, true) &&
+                httpMessage.headers().contains(HttpHeaderNames.UPGRADE, HttpHeaderValues.WEBSOCKET, true);
+    }
+
+    public static List<WebSocketExtensionData> extractExtensions(String extensionHeader) {
+        String[] rawExtensions = StringUtil.split(extensionHeader, EXTENSION_SEPARATOR);
+        if (rawExtensions.length > 0) {
+            List<WebSocketExtensionData> extensions = new ArrayList<WebSocketExtensionData>(rawExtensions.length);
+            for (String rawExtension : rawExtensions) {
+                String[] extensionParameters = StringUtil.split(rawExtension, PARAMETER_SEPARATOR);
+                String name = extensionParameters[0].trim();
+                Map<String, String> parameters;
+                if (extensionParameters.length > 1) {
+                    parameters = new HashMap<String, String>(extensionParameters.length - 1);
+                    for (int i = 1; i < extensionParameters.length; i++) {
+                        String parameter = extensionParameters[i].trim();
+                        Matcher parameterMatcher = PARAMETER.matcher(parameter);
+                        if (parameterMatcher.matches() && parameterMatcher.group(1) != null) {
+                            parameters.put(parameterMatcher.group(1), parameterMatcher.group(3));
+                        }
+                    }
+                } else {
+                    parameters = Collections.<String, String>emptyMap();
+                }
+                extensions.add(new WebSocketExtensionData(name, parameters));
+            }
+            return extensions;
+        } else {
+            return Collections.emptyList();
+        }
+    }
+
+    static String appendExtension(String currentHeaderValue, String extensionName,
+            Map<String, String> extensionParameters) {
+
+        StringBuilder newHeaderValue = new StringBuilder(
+                currentHeaderValue != null ? currentHeaderValue.length() : 0 + extensionName.length() + 1);
+        if (currentHeaderValue != null && !currentHeaderValue.trim().isEmpty()) {
+            newHeaderValue.append(currentHeaderValue);
+            newHeaderValue.append(EXTENSION_SEPARATOR);
+        }
+        newHeaderValue.append(extensionName);
+        boolean isFirst = true;
+        for (Entry<String, String> extensionParameter : extensionParameters.entrySet()) {
+            if (isFirst) {
+                newHeaderValue.append(PARAMETER_SEPARATOR);
+            } else {
+                isFirst = false;
+            }
+            newHeaderValue.append(extensionParameter.getKey());
+            if (extensionParameter.getValue() != null) {
+                newHeaderValue.append(PARAMETER_EQUAL);
+                newHeaderValue.append(extensionParameter.getValue());
+            }
+        }
+        return newHeaderValue.toString();
+    }
+
+    private WebSocketExtensionUtil() {
+        // Unused
+    }
+}

codec-http/src/main/java/io/netty/handler/codec/http/websocketx/extensions/WebSocketServerExtension.java

@@ -0,0 +1,31 @@
+/*
+ * Copyright 2014 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.extensions;
+
+
+/**
+ * Created once the handshake phase is done.
+ */
+public interface WebSocketServerExtension extends WebSocketExtension {
+
+    /**
+     * Return an extension configuration to submit to the client as an acknowledge.
+     *
+     * @return the acknowledged extension configuration.
+     */
+    WebSocketExtensionData newReponseData();
+
+}

codec-http/src/main/java/io/netty/handler/codec/http/websocketx/extensions/WebSocketServerExtensionHandler.java

@@ -0,0 +1,141 @@
+/*
+ * Copyright 2014 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.extensions;
+
+import io.netty.channel.ChannelDuplexHandler;
+import io.netty.channel.ChannelFuture;
+import io.netty.channel.ChannelFutureListener;
+import io.netty.channel.ChannelHandlerContext;
+import io.netty.channel.ChannelPromise;
+import io.netty.handler.codec.http.HttpHeaderNames;
+import io.netty.handler.codec.http.HttpRequest;
+import io.netty.handler.codec.http.HttpResponse;
+
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Iterator;
+import java.util.List;
+
+/**
+ * This handler negotiates and initializes the WebSocket Extensions.
+ *
+ * It negotiates the extensions based on the client desired order,
+ * ensures that the successfully negotiated extensions are consistent between them,
+ * and initializes the channel pipeline with the extension decoder and encoder.
+ *
+ * Find a basic implementation for compression extensions at
+ * <tt>io.netty.handler.codec.http.websocketx.extensions.compression.WebSocketServerCompressionHandler</tt>.
+ */
+public class WebSocketServerExtensionHandler extends ChannelDuplexHandler {
+
+    private final List<WebSocketServerExtensionHandshaker> extensionHandshakers;
+
+    private List<WebSocketServerExtension> validExtensions;
+
+    /**
+     * Constructor
+     *
+     * @param extensionHandshakers
+     *      The extension handshaker in priority order. A handshaker could be repeated many times
+     *      with fallback configuration.
+     */
+    public WebSocketServerExtensionHandler(WebSocketServerExtensionHandshaker... extensionHandshakers) {
+        if (extensionHandshakers == null) {
+            throw new NullPointerException("extensionHandshakers");
+        }
+        if (extensionHandshakers.length == 0) {
+            throw new IllegalArgumentException("extensionHandshakers must contains at least one handshaker");
+        }
+        this.extensionHandshakers = Arrays.asList(extensionHandshakers);
+    }
+
+    @Override
+    public void channelRead(ChannelHandlerContext ctx, Object msg)
+            throws Exception {
+        if (msg instanceof HttpRequest) {
+            HttpRequest request = (HttpRequest) msg;
+
+            if (WebSocketExtensionUtil.isWebsocketUpgrade(request)) {
+                String extensionsHeader = request.headers().getAsString(HttpHeaderNames.SEC_WEBSOCKET_EXTENSIONS);
+
+                if (extensionsHeader != null) {
+                    List<WebSocketExtensionData> extensions =
+                            WebSocketExtensionUtil.extractExtensions(extensionsHeader);
+                    int rsv = 0;
+
+                    for (WebSocketExtensionData extensionData : extensions) {
+                        Iterator<WebSocketServerExtensionHandshaker> extensionHandshakersIterator =
+                                extensionHandshakers.iterator();
+                        WebSocketServerExtension validExtension = null;
+
+                        while (validExtension == null && extensionHandshakersIterator.hasNext()) {
+                            WebSocketServerExtensionHandshaker extensionHandshaker =
+                                    extensionHandshakersIterator.next();
+                            validExtension = extensionHandshaker.handshakeExtension(extensionData);
+                        }
+
+                        if (validExtension != null && ((validExtension.rsv() & rsv) == 0)) {
+                            if (validExtensions == null) {
+                                validExtensions = new ArrayList<WebSocketServerExtension>(1);
+                            }
+                            rsv = rsv | validExtension.rsv();
+                            validExtensions.add(validExtension);
+                        }
+                    }
+                }
+            }
+        }
+
+        super.channelRead(ctx, msg);
+    }
+
+    @Override
+    public void write(final ChannelHandlerContext ctx, Object msg, ChannelPromise promise) throws Exception {
+        if (msg instanceof HttpResponse &&
+                WebSocketExtensionUtil.isWebsocketUpgrade((HttpResponse) msg) && validExtensions != null) {
+            HttpResponse response = (HttpResponse) msg;
+            String headerValue = response.headers().getAsString(HttpHeaderNames.SEC_WEBSOCKET_EXTENSIONS);
+
+            for (WebSocketServerExtension extension : validExtensions) {
+                WebSocketExtensionData extensionData = extension.newReponseData();
+                headerValue = WebSocketExtensionUtil.appendExtension(headerValue,
+                        extensionData.name(), extensionData.parameters());
+            }
+
+            promise.addListener(new ChannelFutureListener() {
+                @Override
+                public void operationComplete(ChannelFuture future) throws Exception {
+                    if (future.isSuccess()) {
+                        for (WebSocketServerExtension extension : validExtensions) {
+                            WebSocketExtensionDecoder decoder = extension.newExtensionDecoder();
+                            WebSocketExtensionEncoder encoder = extension.newExtensionEncoder();
+                            ctx.pipeline().addAfter(ctx.name(), decoder.getClass().getName(), decoder);
+                            ctx.pipeline().addAfter(ctx.name(), encoder.getClass().getName(), encoder);
+                        }
+                    }
+
+                    ctx.pipeline().remove(ctx.name());
+                }
+            });
+
+            if (headerValue != null) {
+                response.headers().set(HttpHeaderNames.SEC_WEBSOCKET_EXTENSIONS, headerValue);
+            }
+        }
+
+        super.write(ctx, msg, promise);
+    }
+}

codec-http/src/main/java/io/netty/handler/codec/http/websocketx/extensions/WebSocketServerExtensionHandshaker.java

@@ -0,0 +1,33 @@
+/*
+ * Copyright 2014 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.extensions;
+
+
+/**
+ * Handshakes a client extension based on this server capabilities.
+ */
+public interface WebSocketServerExtensionHandshaker {
+
+    /**
+     * Handshake based on client request. It must failed with <tt>null</tt> if server cannot handle it.
+     *
+     * @param extensionData
+     *          the extension configuration sent by the client.
+     * @return an initialized extension if handshake phase succeed or null if failed.
+     */
+    WebSocketServerExtension handshakeExtension(WebSocketExtensionData extensionData);
+
+}

codec-http/src/main/java/io/netty/handler/codec/http/websocketx/extensions/compression/DeflateDecoder.java

@@ -0,0 +1,144 @@
+/*
+ * Copyright 2014 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.extensions.compression;
+
+import io.netty.buffer.ByteBuf;
+import io.netty.buffer.CompositeByteBuf;
+import io.netty.buffer.Unpooled;
+import io.netty.channel.ChannelHandlerContext;
+import io.netty.channel.embedded.EmbeddedChannel;
+import io.netty.handler.codec.CodecException;
+import io.netty.handler.codec.MessageToMessageDecoder;
+import io.netty.handler.codec.compression.ZlibCodecFactory;
+import io.netty.handler.codec.compression.ZlibWrapper;
+import io.netty.handler.codec.http.DefaultHttpContent;
+import io.netty.handler.codec.http.websocketx.BinaryWebSocketFrame;
+import io.netty.handler.codec.http.websocketx.ContinuationWebSocketFrame;
+import io.netty.handler.codec.http.websocketx.TextWebSocketFrame;
+import io.netty.handler.codec.http.websocketx.WebSocketFrame;
+import io.netty.handler.codec.http.websocketx.extensions.WebSocketExtension;
+import io.netty.handler.codec.http.websocketx.extensions.WebSocketExtensionDecoder;
+import io.netty.util.ReferenceCountUtil;
+
+import java.util.List;
+
+/**
+ * Deflate implementation of a payload decompressor for
+ * <tt>io.netty.handler.codec.http.websocketx.WebSocketFrame</tt>.
+ */
+abstract class DeflateDecoder extends WebSocketExtensionDecoder {
+
+    static final byte[] FRAME_TAIL = new byte[] {0x00, 0x00, (byte) 0xff, (byte) 0xff};
+
+    private final boolean noContext;
+
+    private EmbeddedChannel decoder;
+
+    /**
+     * Constructor
+     * @param noContext true to disable context takeover.
+     */
+    public DeflateDecoder(boolean noContext) {
+        this.noContext = noContext;
+    }
+
+    protected abstract boolean appendFrameTail(WebSocketFrame msg);
+
+    protected abstract int newRsv(WebSocketFrame msg);
+
+    @Override
+    protected void decode(ChannelHandlerContext ctx, WebSocketFrame msg, List<Object> out) throws Exception {
+        if (decoder == null) {
+            if (!(msg instanceof TextWebSocketFrame) && !(msg instanceof BinaryWebSocketFrame)) {
+                throw new CodecException("unexpected initial frame type: " + msg.getClass().getName());
+            }
+            decoder = new EmbeddedChannel(ZlibCodecFactory.newZlibDecoder(ZlibWrapper.NONE));
+        }
+
+        boolean readable = msg.content().isReadable();
+        decoder.writeInbound(msg.content().retain());
+        if (appendFrameTail(msg)) {
+            decoder.writeInbound(Unpooled.wrappedBuffer(FRAME_TAIL));
+        }
+
+        CompositeByteBuf compositeUncompressedContent = ctx.alloc().compositeBuffer();
+        for (;;) {
+            ByteBuf partUncompressedContent = decoder.readInbound();
+            if (partUncompressedContent == null) {
+                break;
+            }
+            if (!partUncompressedContent.isReadable()) {
+                partUncompressedContent.release();
+                continue;
+            }
+            compositeUncompressedContent.addComponent(partUncompressedContent);
+            compositeUncompressedContent.writerIndex(compositeUncompressedContent.writerIndex() +
+                    partUncompressedContent.readableBytes());
+        }
+        // Correctly handle empty frames
+        // See https://github.com/netty/netty/issues/4348
+        if (readable && compositeUncompressedContent.numComponents() <= 0) {
+            compositeUncompressedContent.release();
+            throw new CodecException("cannot read uncompressed buffer");
+        }
+
+        if (msg.isFinalFragment() && noContext) {
+            cleanup();
+        }
+
+        WebSocketFrame outMsg;
+        if (msg instanceof TextWebSocketFrame) {
+            outMsg = new TextWebSocketFrame(msg.isFinalFragment(), newRsv(msg), compositeUncompressedContent);
+        } else if (msg instanceof BinaryWebSocketFrame) {
+            outMsg = new BinaryWebSocketFrame(msg.isFinalFragment(), newRsv(msg), compositeUncompressedContent);
+        } else if (msg instanceof ContinuationWebSocketFrame) {
+            outMsg = new ContinuationWebSocketFrame(msg.isFinalFragment(), newRsv(msg),
+                    compositeUncompressedContent);
+        } else {
+            throw new CodecException("unexpected frame type: " + msg.getClass().getName());
+        }
+        out.add(outMsg);
+    }
+
+    @Override
+    public void handlerRemoved(ChannelHandlerContext ctx) throws Exception {
+        cleanup();
+        super.handlerRemoved(ctx);
+    }
+
+    @Override
+    public void channelInactive(ChannelHandlerContext ctx) throws Exception {
+        cleanup();
+        super.channelInactive(ctx);
+    }
+
+    private void cleanup() {
+        if (decoder != null) {
+            // Clean-up the previous encoder if not cleaned up correctly.
+            if (decoder.finish()) {
+                for (;;) {
+                    ByteBuf buf = decoder.readOutbound();
+                    if (buf == null) {
+                        break;
+                    }
+                    // Release the buffer
+                    buf.release();
+                }
+            }
+            decoder = null;
+        }
+    }
+}

codec-http/src/main/java/io/netty/handler/codec/http/websocketx/extensions/compression/DeflateEncoder.java

@@ -0,0 +1,146 @@
+/*
+ * Copyright 2014 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.extensions.compression;
+
+import static io.netty.handler.codec.http.websocketx.extensions.compression.PerMessageDeflateDecoder.*;
+import io.netty.buffer.ByteBuf;
+import io.netty.buffer.CompositeByteBuf;
+import io.netty.channel.ChannelHandlerContext;
+import io.netty.channel.embedded.EmbeddedChannel;
+import io.netty.handler.codec.CodecException;
+import io.netty.handler.codec.compression.ZlibCodecFactory;
+import io.netty.handler.codec.compression.ZlibWrapper;
+import io.netty.handler.codec.http.websocketx.BinaryWebSocketFrame;
+import io.netty.handler.codec.http.websocketx.ContinuationWebSocketFrame;
+import io.netty.handler.codec.http.websocketx.TextWebSocketFrame;
+import io.netty.handler.codec.http.websocketx.WebSocketFrame;
+import io.netty.handler.codec.http.websocketx.extensions.WebSocketExtensionEncoder;
+
+import java.util.List;
+
+/**
+ * Deflate implementation of a payload compressor for
+ * <tt>io.netty.handler.codec.http.websocketx.WebSocketFrame</tt>.
+ */
+abstract class DeflateEncoder extends WebSocketExtensionEncoder {
+
+    private final int compressionLevel;
+    private final int windowSize;
+    private final boolean noContext;
+
+    private EmbeddedChannel encoder;
+
+    /**
+     * Constructor
+     * @param compressionLevel compression level of the compressor.
+     * @param windowSize maximum size of the window compressor buffer.
+     * @param noContext true to disable context takeover.
+     */
+    public DeflateEncoder(int compressionLevel, int windowSize, boolean noContext) {
+        this.compressionLevel = compressionLevel;
+        this.windowSize = windowSize;
+        this.noContext = noContext;
+    }
+
+    /**
+     * @param msg the current frame.
+     * @return the rsv bits to set in the compressed frame.
+     */
+    protected abstract int rsv(WebSocketFrame msg);
+
+    /**
+     * @param msg the current frame.
+     * @return true if compressed payload tail needs to be removed.
+     */
+    protected abstract boolean removeFrameTail(WebSocketFrame msg);
+
+    @Override
+    protected void encode(ChannelHandlerContext ctx, WebSocketFrame msg,
+            List<Object> out) throws Exception {
+        if (encoder == null) {
+            encoder = new EmbeddedChannel(ZlibCodecFactory.newZlibEncoder(
+                    ZlibWrapper.NONE, compressionLevel, windowSize, 8));
+        }
+
+        encoder.writeOutbound(msg.content().retain());
+
+        CompositeByteBuf fullCompressedContent = ctx.alloc().compositeBuffer();
+        for (;;) {
+            ByteBuf partCompressedContent = encoder.readOutbound();
+            if (partCompressedContent == null) {
+                break;
+            }
+            if (!partCompressedContent.isReadable()) {
+                partCompressedContent.release();
+                continue;
+            }
+            fullCompressedContent.addComponent(partCompressedContent);
+            fullCompressedContent.writerIndex(fullCompressedContent.writerIndex() +
+                    partCompressedContent.readableBytes());
+        }
+        if (fullCompressedContent.numComponents() <= 0) {
+            fullCompressedContent.release();
+            throw new CodecException("cannot read compressed buffer");
+        }
+
+        if (msg.isFinalFragment() && noContext) {
+            cleanup();
+        }
+
+        ByteBuf compressedContent;
+        if (removeFrameTail(msg)) {
+            int realLength = fullCompressedContent.readableBytes() - FRAME_TAIL.length;
+            compressedContent = fullCompressedContent.slice(0, realLength);
+        } else {
+            compressedContent = fullCompressedContent;
+        }
+
+        WebSocketFrame outMsg;
+        if (msg instanceof TextWebSocketFrame) {
+            outMsg = new TextWebSocketFrame(msg.isFinalFragment(), rsv(msg), compressedContent);
+        } else if (msg instanceof BinaryWebSocketFrame) {
+            outMsg = new BinaryWebSocketFrame(msg.isFinalFragment(), rsv(msg), compressedContent);
+        } else if (msg instanceof ContinuationWebSocketFrame) {
+            outMsg = new ContinuationWebSocketFrame(msg.isFinalFragment(), rsv(msg), compressedContent);
+        } else {
+            throw new CodecException("unexpected frame type: " + msg.getClass().getName());
+        }
+        out.add(outMsg);
+    }
+
+    @Override
+    public void handlerRemoved(ChannelHandlerContext ctx) throws Exception {
+        cleanup();
+        super.handlerRemoved(ctx);
+    }
+
+    private void cleanup() {
+        if (encoder != null) {
+            // Clean-up the previous encoder if not cleaned up correctly.
+            if (encoder.finish()) {
+                for (;;) {
+                    ByteBuf buf = encoder.readOutbound();
+                    if (buf == null) {
+                        break;
+                    }
+                    // Release the buffer
+                    buf.release();
+                }
+            }
+            encoder = null;
+        }
+    }
+}

codec-http/src/main/java/io/netty/handler/codec/http/websocketx/extensions/compression/DeflateFrameClientExtensionHandshaker.java

@@ -0,0 +1,104 @@
+/*
+ * Copyright 2014 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.extensions.compression;
+
+import static io.netty.handler.codec.http.websocketx.extensions.compression.
+        DeflateFrameServerExtensionHandshaker.*;
+import io.netty.handler.codec.http.websocketx.extensions.WebSocketClientExtension;
+import io.netty.handler.codec.http.websocketx.extensions.WebSocketClientExtensionHandshaker;
+import io.netty.handler.codec.http.websocketx.extensions.WebSocketExtensionData;
+import io.netty.handler.codec.http.websocketx.extensions.WebSocketExtensionDecoder;
+import io.netty.handler.codec.http.websocketx.extensions.WebSocketExtensionEncoder;
+
+import java.util.Collections;
+
+/**
+ * <a href="https://tools.ietf.org/id/draft-tyoshino-hybi-websocket-perframe-deflate-06.txt">perframe-deflate</a>
+ * handshake implementation.
+ */
+public final class DeflateFrameClientExtensionHandshaker implements WebSocketClientExtensionHandshaker {
+
+    private final int compressionLevel;
+    private final boolean useWebkitExtensionName;
+
+    /**
+     * Constructor with default configuration.
+     */
+    public DeflateFrameClientExtensionHandshaker(boolean useWebkitExtensionName) {
+        this(6, useWebkitExtensionName);
+    }
+
+    /**
+     * Constructor with custom configuration.
+     *
+     * @param compressionLevel
+     *            Compression level between 0 and 9 (default is 6).
+     */
+    public DeflateFrameClientExtensionHandshaker(int compressionLevel, boolean useWebkitExtensionName) {
+        if (compressionLevel < 0 || compressionLevel > 9) {
+            throw new IllegalArgumentException(
+                    "compressionLevel: " + compressionLevel + " (expected: 0-9)");
+        }
+        this.compressionLevel = compressionLevel;
+        this.useWebkitExtensionName = useWebkitExtensionName;
+    }
+
+    @Override
+    public WebSocketExtensionData newRequestData() {
+        return new WebSocketExtensionData(
+                useWebkitExtensionName ? X_WEBKIT_DEFLATE_FRAME_EXTENSION : DEFLATE_FRAME_EXTENSION,
+                Collections.<String, String>emptyMap());
+    }
+
+    @Override
+    public WebSocketClientExtension handshakeExtension(WebSocketExtensionData extensionData) {
+        if (!X_WEBKIT_DEFLATE_FRAME_EXTENSION.equals(extensionData.name()) &&
+            !DEFLATE_FRAME_EXTENSION.equals(extensionData.name())) {
+            return null;
+        }
+
+        if (extensionData.parameters().isEmpty()) {
+            return new DeflateFrameClientExtension(compressionLevel);
+        } else {
+            return null;
+        }
+    }
+
+    private static class DeflateFrameClientExtension implements WebSocketClientExtension {
+
+        private final int compressionLevel;
+
+        public DeflateFrameClientExtension(int compressionLevel) {
+            this.compressionLevel = compressionLevel;
+        }
+
+        @Override
+        public int rsv() {
+            return RSV1;
+        }
+
+        @Override
+        public WebSocketExtensionEncoder newExtensionEncoder() {
+            return new PerFrameDeflateEncoder(compressionLevel, 15, false);
+        }
+
+        @Override
+        public WebSocketExtensionDecoder newExtensionDecoder() {
+            return new PerFrameDeflateDecoder(false);
+        }
+    }
+
+}

codec-http/src/main/java/io/netty/handler/codec/http/websocketx/extensions/compression/DeflateFrameServerExtensionHandshaker.java

@@ -0,0 +1,103 @@
+/*
+ * Copyright 2014 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.extensions.compression;
+
+import io.netty.handler.codec.http.websocketx.extensions.WebSocketExtensionData;
+import io.netty.handler.codec.http.websocketx.extensions.WebSocketExtensionDecoder;
+import io.netty.handler.codec.http.websocketx.extensions.WebSocketExtensionEncoder;
+import io.netty.handler.codec.http.websocketx.extensions.WebSocketServerExtension;
+import io.netty.handler.codec.http.websocketx.extensions.WebSocketServerExtensionHandshaker;
+
+import java.util.Collections;
+
+/**
+ * <a href="https://tools.ietf.org/id/draft-tyoshino-hybi-websocket-perframe-deflate-06.txt">perframe-deflate</a>
+ * handshake implementation.
+ */
+public final class DeflateFrameServerExtensionHandshaker implements WebSocketServerExtensionHandshaker {
+
+    static final String X_WEBKIT_DEFLATE_FRAME_EXTENSION = "x-webkit-deflate-frame";
+    static final String DEFLATE_FRAME_EXTENSION = "deflate-frame";
+
+    private final int compressionLevel;
+
+    /**
+     * Constructor with default configuration.
+     */
+    public DeflateFrameServerExtensionHandshaker() {
+        this(6);
+    }
+
+    /**
+     * Constructor with custom configuration.
+     *
+     * @param compressionLevel
+     *            Compression level between 0 and 9 (default is 6).
+     */
+    public DeflateFrameServerExtensionHandshaker(int compressionLevel) {
+        if (compressionLevel < 0 || compressionLevel > 9) {
+            throw new IllegalArgumentException(
+                    "compressionLevel: " + compressionLevel + " (expected: 0-9)");
+        }
+        this.compressionLevel = compressionLevel;
+    }
+
+    @Override
+    public WebSocketServerExtension handshakeExtension(WebSocketExtensionData extensionData) {
+        if (!X_WEBKIT_DEFLATE_FRAME_EXTENSION.equals(extensionData.name()) &&
+            !DEFLATE_FRAME_EXTENSION.equals(extensionData.name())) {
+            return null;
+        }
+
+        if (extensionData.parameters().isEmpty()) {
+            return new DeflateFrameServerExtension(compressionLevel, extensionData.name());
+        } else {
+            return null;
+        }
+    }
+
+    private static class DeflateFrameServerExtension implements WebSocketServerExtension {
+
+        private final String extensionName;
+        private final int compressionLevel;
+
+        public DeflateFrameServerExtension(int compressionLevel, String extensionName) {
+            this.extensionName = extensionName;
+            this.compressionLevel = compressionLevel;
+        }
+
+        @Override
+        public int rsv() {
+            return RSV1;
+        }
+
+        @Override
+        public WebSocketExtensionEncoder newExtensionEncoder() {
+            return new PerFrameDeflateEncoder(compressionLevel, 15, false);
+        }
+
+        @Override
+        public WebSocketExtensionDecoder newExtensionDecoder() {
+            return new PerFrameDeflateDecoder(false);
+        }
+
+        @Override
+        public WebSocketExtensionData newReponseData() {
+            return new WebSocketExtensionData(extensionName, Collections.<String, String>emptyMap());
+        }
+    }
+
+}

codec-http/src/main/java/io/netty/handler/codec/http/websocketx/extensions/compression/PerFrameDeflateDecoder.java

@@ -0,0 +1,54 @@
+/*
+ * Copyright 2014 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.extensions.compression;
+
+import io.netty.handler.codec.http.websocketx.BinaryWebSocketFrame;
+import io.netty.handler.codec.http.websocketx.ContinuationWebSocketFrame;
+import io.netty.handler.codec.http.websocketx.TextWebSocketFrame;
+import io.netty.handler.codec.http.websocketx.WebSocketFrame;
+import io.netty.handler.codec.http.websocketx.extensions.WebSocketExtension;
+
+/**
+ * Per-frame implementation of deflate decompressor.
+ */
+class PerFrameDeflateDecoder extends DeflateDecoder {
+
+    /**
+     * Constructor
+     * @param noContext true to disable context takeover.
+     */
+    public PerFrameDeflateDecoder(boolean noContext) {
+        super(noContext);
+    }
+
+    @Override
+    public boolean acceptInboundMessage(Object msg) throws Exception {
+        return (msg instanceof TextWebSocketFrame ||
+                msg instanceof BinaryWebSocketFrame ||
+                msg instanceof ContinuationWebSocketFrame) &&
+                    (((WebSocketFrame) msg).rsv() & WebSocketExtension.RSV1) > 0;
+    }
+
+    @Override
+    protected int newRsv(WebSocketFrame msg) {
+        return msg.rsv() ^ WebSocketExtension.RSV1;
+    }
+
+    @Override
+    protected boolean appendFrameTail(WebSocketFrame msg) {
+        return true;
+    }
+}

codec-http/src/main/java/io/netty/handler/codec/http/websocketx/extensions/compression/PerFrameDeflateEncoder.java

@@ -0,0 +1,58 @@
+/*
+ * Copyright 2014 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.extensions.compression;
+
+import io.netty.handler.codec.http.websocketx.BinaryWebSocketFrame;
+import io.netty.handler.codec.http.websocketx.ContinuationWebSocketFrame;
+import io.netty.handler.codec.http.websocketx.TextWebSocketFrame;
+import io.netty.handler.codec.http.websocketx.WebSocketFrame;
+import io.netty.handler.codec.http.websocketx.extensions.WebSocketExtension;
+
+/**
+ * Per-frame implementation of deflate compressor.
+ */
+class PerFrameDeflateEncoder extends DeflateEncoder {
+
+    /**
+     * Constructor
+     * @param compressionLevel compression level of the compressor.
+     * @param windowSize maximum size of the window compressor buffer.
+     * @param noContext true to disable context takeover.
+     */
+    public PerFrameDeflateEncoder(int compressionLevel, int windowSize, boolean noContext) {
+        super(compressionLevel, windowSize, noContext);
+    }
+
+    @Override
+    public boolean acceptOutboundMessage(Object msg) throws Exception {
+        return (msg instanceof TextWebSocketFrame ||
+                msg instanceof BinaryWebSocketFrame ||
+                msg instanceof ContinuationWebSocketFrame) &&
+                    ((WebSocketFrame) msg).content().readableBytes() > 0 &&
+                    (((WebSocketFrame) msg).rsv() & WebSocketExtension.RSV1) == 0;
+    }
+
+    @Override
+    protected int rsv(WebSocketFrame msg) {
+        return msg.rsv() | WebSocketExtension.RSV1;
+    }
+
+    @Override
+    protected boolean removeFrameTail(WebSocketFrame msg) {
+        return true;
+    }
+
+}

codec-http/src/main/java/io/netty/handler/codec/http/websocketx/extensions/compression/PerMessageDeflateClientExtensionHandshaker.java

@@ -0,0 +1,197 @@
+/*
+ * Copyright 2014 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.extensions.compression;
+
+import static io.netty.handler.codec.http.websocketx.extensions.compression.
+        PerMessageDeflateServerExtensionHandshaker.*;
+import io.netty.handler.codec.http.websocketx.extensions.WebSocketClientExtension;
+import io.netty.handler.codec.http.websocketx.extensions.WebSocketClientExtensionHandshaker;
+import io.netty.handler.codec.http.websocketx.extensions.WebSocketExtensionData;
+import io.netty.handler.codec.http.websocketx.extensions.WebSocketExtensionDecoder;
+import io.netty.handler.codec.http.websocketx.extensions.WebSocketExtensionEncoder;
+
+import java.util.HashMap;
+import java.util.Iterator;
+import java.util.Map;
+import java.util.Map.Entry;
+
+/**
+ * <a href="http://tools.ietf.org/html/draft-ietf-hybi-permessage-compression-18">permessage-deflate</a>
+ * handshake implementation.
+ */
+public final class PerMessageDeflateClientExtensionHandshaker implements WebSocketClientExtensionHandshaker {
+
+    private final int compressionLevel;
+    private final boolean allowClientWindowSize;
+    private final int requestedServerWindowSize;
+    private final boolean allowClientNoContext;
+    private final boolean requestedServerNoContext;
+
+    /**
+     * Constructor with default configuration.
+     */
+    public PerMessageDeflateClientExtensionHandshaker() {
+        this(6, false, MAX_WINDOW_SIZE, false, false);
+    }
+
+    /**
+     * Constructor with custom configuration.
+     *
+     * @param compressionLevel
+     *            Compression level between 0 and 9 (default is 6).
+     * @param allowClientWindowSize
+     *            allows WebSocket server to customize the client inflater window size
+     *            (default is false).
+     * @param requestedServerWindowSize
+     *            indicates the requested sever window size to use if server inflater is customizable.
+     * @param allowClientNoContext
+     *            allows WebSocket server to activate client_no_context_takeover
+     *            (default is false).
+     * @param requestedServerNoContext
+     *            indicates if client needs to activate server_no_context_takeover
+     *            if server is compatible with (default is false).
+     */
+    public PerMessageDeflateClientExtensionHandshaker(int compressionLevel,
+            boolean allowClientWindowSize, int requestedServerWindowSize,
+            boolean allowClientNoContext, boolean requestedServerNoContext) {
+        if (requestedServerWindowSize > MAX_WINDOW_SIZE || requestedServerWindowSize < MIN_WINDOW_SIZE) {
+            throw new IllegalArgumentException(
+                    "requestedServerWindowSize: " + requestedServerWindowSize + " (expected: 8-15)");
+        }
+        if (compressionLevel < 0 || compressionLevel > 9) {
+            throw new IllegalArgumentException(
+                    "compressionLevel: " + compressionLevel + " (expected: 0-9)");
+        }
+        this.compressionLevel = compressionLevel;
+        this.allowClientWindowSize = allowClientWindowSize;
+        this.requestedServerWindowSize = requestedServerWindowSize;
+        this.allowClientNoContext = allowClientNoContext;
+        this.requestedServerNoContext = requestedServerNoContext;
+    }
+
+    @Override
+    public WebSocketExtensionData newRequestData() {
+        HashMap<String, String> parameters = new HashMap<String, String>(4);
+        if (requestedServerWindowSize != MAX_WINDOW_SIZE) {
+            parameters.put(SERVER_NO_CONTEXT, null);
+        }
+        if (allowClientNoContext) {
+            parameters.put(CLIENT_NO_CONTEXT, null);
+        }
+        if (requestedServerWindowSize != MAX_WINDOW_SIZE) {
+            parameters.put(SERVER_MAX_WINDOW, Integer.toString(requestedServerWindowSize));
+        }
+        if (allowClientWindowSize) {
+            parameters.put(CLIENT_MAX_WINDOW, null);
+        }
+        return new WebSocketExtensionData(PERMESSAGE_DEFLATE_EXTENSION, parameters);
+    }
+
+    @Override
+    public WebSocketClientExtension handshakeExtension(WebSocketExtensionData extensionData) {
+        if (!PERMESSAGE_DEFLATE_EXTENSION.equals(extensionData.name())) {
+            return null;
+        }
+
+        boolean succeed = true;
+        int clientWindowSize = MAX_WINDOW_SIZE;
+        int serverWindowSize = MAX_WINDOW_SIZE;
+        boolean serverNoContext = false;
+        boolean clientNoContext = false;
+
+        Iterator<Entry<String, String>> parametersIterator =
+                extensionData.parameters().entrySet().iterator();
+        while (succeed && parametersIterator.hasNext()) {
+            Entry<String, String> parameter = parametersIterator.next();
+
+            if (CLIENT_MAX_WINDOW.equalsIgnoreCase(parameter.getKey())) {
+                // allowed client_window_size_bits
+                if (allowClientWindowSize) {
+                    clientWindowSize = Integer.parseInt(parameter.getValue());
+                } else {
+                    succeed = false;
+                }
+            } else if (SERVER_MAX_WINDOW.equalsIgnoreCase(parameter.getKey())) {
+                // acknowledged server_window_size_bits
+                serverWindowSize = Integer.parseInt(parameter.getValue());
+                if (clientWindowSize > MAX_WINDOW_SIZE || clientWindowSize < MIN_WINDOW_SIZE) {
+                    succeed = false;
+                }
+            } else if (CLIENT_NO_CONTEXT.equalsIgnoreCase(parameter.getKey())) {
+                // allowed client_no_context_takeover
+                if (allowClientNoContext) {
+                    clientNoContext = true;
+                } else {
+                    succeed = false;
+                }
+            } else if (SERVER_NO_CONTEXT.equalsIgnoreCase(parameter.getKey())) {
+                // acknowledged server_no_context_takeover
+                if (requestedServerNoContext) {
+                    serverNoContext = true;
+                } else {
+                    succeed = false;
+                }
+            } else {
+                // unknown parameter
+                succeed = false;
+            }
+        }
+
+        if ((requestedServerNoContext && !serverNoContext) ||
+                requestedServerWindowSize != serverWindowSize) {
+            succeed = false;
+        }
+
+        if (succeed) {
+            return new PermessageDeflateExtension(serverNoContext, serverWindowSize,
+                    clientNoContext, clientWindowSize);
+        } else {
+            return null;
+        }
+    }
+
+    private final class PermessageDeflateExtension implements WebSocketClientExtension {
+
+        private final boolean serverNoContext;
+        private final int serverWindowSize;
+        private final boolean clientNoContext;
+        private final int clientWindowSize;
+
+        @Override
+        public int rsv() {
+            return RSV1;
+        }
+
+        public PermessageDeflateExtension(boolean serverNoContext, int serverWindowSize,
+                boolean clientNoContext, int clientWindowSize) {
+            this.serverNoContext = serverNoContext;
+            this.serverWindowSize = serverWindowSize;
+            this.clientNoContext = clientNoContext;
+            this.clientWindowSize = clientWindowSize;
+        }
+
+        @Override
+        public WebSocketExtensionEncoder newExtensionEncoder() {
+            return new PerMessageDeflateEncoder(compressionLevel, serverWindowSize, serverNoContext);
+        }
+
+        @Override
+        public WebSocketExtensionDecoder newExtensionDecoder() {
+            return new PerMessageDeflateDecoder(clientNoContext);
+        }
+    }
+
+}

codec-http/src/main/java/io/netty/handler/codec/http/websocketx/extensions/compression/PerMessageDeflateDecoder.java

@@ -0,0 +1,72 @@
+/*
+ * Copyright 2014 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.extensions.compression;
+
+import io.netty.channel.ChannelHandlerContext;
+import io.netty.handler.codec.http.websocketx.BinaryWebSocketFrame;
+import io.netty.handler.codec.http.websocketx.ContinuationWebSocketFrame;
+import io.netty.handler.codec.http.websocketx.TextWebSocketFrame;
+import io.netty.handler.codec.http.websocketx.WebSocketFrame;
+import io.netty.handler.codec.http.websocketx.extensions.WebSocketExtension;
+
+import java.util.List;
+
+/**
+ * Per-message implementation of deflate decompressor.
+ */
+class PerMessageDeflateDecoder extends DeflateDecoder {
+
+    private boolean compressing;
+
+    /**
+     * Constructor
+     * @param noContext true to disable context takeover.
+     */
+    public PerMessageDeflateDecoder(boolean noContext) {
+        super(noContext);
+    }
+
+    @Override
+    public boolean acceptInboundMessage(Object msg) throws Exception {
+        return ((msg instanceof TextWebSocketFrame ||
+                 msg instanceof BinaryWebSocketFrame) &&
+                    (((WebSocketFrame) msg).rsv() & WebSocketExtension.RSV1) > 0) ||
+                (msg instanceof ContinuationWebSocketFrame && compressing);
+    }
+
+    @Override
+    protected int newRsv(WebSocketFrame msg) {
+        return (((WebSocketFrame) msg).rsv() & WebSocketExtension.RSV1) > 0 ?
+                msg.rsv() ^ WebSocketExtension.RSV1 : msg.rsv();
+    }
+
+    @Override
+    protected boolean appendFrameTail(WebSocketFrame msg) {
+        return msg.isFinalFragment();
+    }
+
+    @Override
+    protected void decode(ChannelHandlerContext ctx, WebSocketFrame msg,
+        List<Object> out) throws Exception {
+        super.decode(ctx, msg, out);
+
+        if (msg.isFinalFragment()) {
+            compressing = false;
+        } else if (msg instanceof TextWebSocketFrame || msg instanceof BinaryWebSocketFrame) {
+            compressing = true;
+        }
+    }
+}

codec-http/src/main/java/io/netty/handler/codec/http/websocketx/extensions/compression/PerMessageDeflateEncoder.java

@@ -0,0 +1,75 @@
+/*
+ * Copyright 2014 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.extensions.compression;
+
+import io.netty.channel.ChannelHandlerContext;
+import io.netty.handler.codec.http.websocketx.BinaryWebSocketFrame;
+import io.netty.handler.codec.http.websocketx.ContinuationWebSocketFrame;
+import io.netty.handler.codec.http.websocketx.TextWebSocketFrame;
+import io.netty.handler.codec.http.websocketx.WebSocketFrame;
+import io.netty.handler.codec.http.websocketx.extensions.WebSocketExtension;
+
+import java.util.List;
+
+/**
+ * Per-message implementation of deflate compressor.
+ */
+class PerMessageDeflateEncoder extends DeflateEncoder {
+
+    private boolean compressing;
+
+    /**
+     * Constructor
+     * @param compressionLevel compression level of the compressor.
+     * @param windowSize maximum size of the window compressor buffer.
+     * @param noContext true to disable context takeover.
+     */
+    public PerMessageDeflateEncoder(int compressionLevel, int windowSize, boolean noContext) {
+        super(compressionLevel, windowSize, noContext);
+    }
+
+    @Override
+    public boolean acceptOutboundMessage(Object msg) throws Exception {
+        return ((msg instanceof TextWebSocketFrame ||
+                msg instanceof BinaryWebSocketFrame) &&
+                   (((WebSocketFrame) msg).rsv() & WebSocketExtension.RSV1) == 0) ||
+               (msg instanceof ContinuationWebSocketFrame && compressing);
+    }
+
+    @Override
+    protected int rsv(WebSocketFrame msg) {
+        return msg instanceof TextWebSocketFrame || msg instanceof BinaryWebSocketFrame ?
+                msg.rsv() | WebSocketExtension.RSV1 : msg.rsv();
+    }
+
+    @Override
+    protected boolean removeFrameTail(WebSocketFrame msg) {
+        return msg.isFinalFragment();
+    }
+
+    @Override
+    protected void encode(ChannelHandlerContext ctx, WebSocketFrame msg,
+            List<Object> out) throws Exception {
+        super.encode(ctx, msg, out);
+
+        if (msg.isFinalFragment()) {
+            compressing = false;
+        } else if (msg instanceof TextWebSocketFrame || msg instanceof BinaryWebSocketFrame) {
+            compressing = true;
+        }
+    }
+
+}

codec-http/src/main/java/io/netty/handler/codec/http/websocketx/extensions/compression/PerMessageDeflateServerExtensionHandshaker.java

@@ -0,0 +1,196 @@
+/*
+ * Copyright 2014 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.extensions.compression;
+
+import io.netty.handler.codec.http.websocketx.extensions.WebSocketExtensionData;
+import io.netty.handler.codec.http.websocketx.extensions.WebSocketExtensionDecoder;
+import io.netty.handler.codec.http.websocketx.extensions.WebSocketExtensionEncoder;
+import io.netty.handler.codec.http.websocketx.extensions.WebSocketServerExtension;
+import io.netty.handler.codec.http.websocketx.extensions.WebSocketServerExtensionHandshaker;
+
+import java.util.HashMap;
+import java.util.Iterator;
+import java.util.Map.Entry;
+
+/**
+ * <a href="http://tools.ietf.org/html/draft-ietf-hybi-permessage-compression-18">permessage-deflate</a>
+ * handshake implementation.
+ */
+public final class PerMessageDeflateServerExtensionHandshaker implements WebSocketServerExtensionHandshaker {
+
+    public static final int MIN_WINDOW_SIZE = 8;
+    public static final int MAX_WINDOW_SIZE = 15;
+
+    static final String PERMESSAGE_DEFLATE_EXTENSION = "permessage-deflate";
+    static final String CLIENT_MAX_WINDOW = "client_max_window_bits";
+    static final String SERVER_MAX_WINDOW = "server_max_window_bits";
+    static final String CLIENT_NO_CONTEXT = "client_no_context_takeover";
+    static final String SERVER_NO_CONTEXT = "server_no_context_takeover";
+
+    private final int compressionLevel;
+    private final boolean allowServerWindowSize;
+    private final int preferredClientWindowSize;
+    private final boolean allowServerNoContext;
+    private final boolean preferredClientNoContext;
+
+    /**
+     * Constructor with default configuration.
+     */
+    public PerMessageDeflateServerExtensionHandshaker() {
+        this(6, false, MAX_WINDOW_SIZE, false, false);
+    }
+
+    /**
+     * Constructor with custom configuration.
+     *
+     * @param compressionLevel
+     *            Compression level between 0 and 9 (default is 6).
+     * @param allowServerWindowSize
+     *            allows WebSocket client to customize the server inflater window size
+     *            (default is false).
+     * @param preferredClientWindowSize
+     *            indicates the preferred client window size to use if client inflater is customizable.
+     * @param allowServerNoContext
+     *            allows WebSocket client to activate server_no_context_takeover
+     *            (default is false).
+     * @param preferredClientNoContext
+     *            indicates if server prefers to activate client_no_context_takeover
+     *            if client is compatible with (default is false).
+     */
+    public PerMessageDeflateServerExtensionHandshaker(int compressionLevel,
+            boolean allowServerWindowSize, int preferredClientWindowSize,
+            boolean allowServerNoContext, boolean preferredClientNoContext) {
+        if (preferredClientWindowSize > MAX_WINDOW_SIZE || preferredClientWindowSize < MIN_WINDOW_SIZE) {
+            throw new IllegalArgumentException(
+                    "preferredServerWindowSize: " + preferredClientWindowSize + " (expected: 8-15)");
+        }
+        if (compressionLevel < 0 || compressionLevel > 9) {
+            throw new IllegalArgumentException(
+                    "compressionLevel: " + compressionLevel + " (expected: 0-9)");
+        }
+        this.compressionLevel = compressionLevel;
+        this.allowServerWindowSize = allowServerWindowSize;
+        this.preferredClientWindowSize = preferredClientWindowSize;
+        this.allowServerNoContext = allowServerNoContext;
+        this.preferredClientNoContext = preferredClientNoContext;
+    }
+
+    @Override
+    public WebSocketServerExtension handshakeExtension(WebSocketExtensionData extensionData) {
+        if (!PERMESSAGE_DEFLATE_EXTENSION.equals(extensionData.name())) {
+            return null;
+        }
+
+        boolean deflateEnabled = true;
+        int clientWindowSize = MAX_WINDOW_SIZE;
+        int serverWindowSize = MAX_WINDOW_SIZE;
+        boolean serverNoContext = false;
+        boolean clientNoContext = false;
+
+        Iterator<Entry<String, String>> parametersIterator =
+                extensionData.parameters().entrySet().iterator();
+        while (deflateEnabled && parametersIterator.hasNext()) {
+            Entry<String, String> parameter = parametersIterator.next();
+
+            if (CLIENT_MAX_WINDOW.equalsIgnoreCase(parameter.getKey())) {
+             // use preferred clientWindowSize because client is compatible with customization
+                clientWindowSize = preferredClientWindowSize;
+            } else if (SERVER_MAX_WINDOW.equalsIgnoreCase(parameter.getKey())) {
+                // use provided windowSize if it is allowed
+                if (allowServerWindowSize) {
+                    serverWindowSize = Integer.parseInt(parameter.getValue());
+                    if (serverWindowSize > MAX_WINDOW_SIZE || serverWindowSize < MIN_WINDOW_SIZE) {
+                        deflateEnabled = false;
+                    }
+                } else {
+                    deflateEnabled = false;
+                }
+            } else if (CLIENT_NO_CONTEXT.equalsIgnoreCase(parameter.getKey())) {
+                // use preferred clientNoContext because client is compatible with customization
+                clientNoContext = preferredClientNoContext;
+            } else if (SERVER_NO_CONTEXT.equalsIgnoreCase(parameter.getKey())) {
+                // use server no context if allowed
+                if (allowServerNoContext) {
+                    serverNoContext = true;
+                } else {
+                    deflateEnabled = false;
+                }
+            } else {
+                // unknown parameter
+                deflateEnabled = false;
+            }
+        }
+
+        if (deflateEnabled) {
+            return new PermessageDeflateExtension(compressionLevel, serverNoContext,
+                    serverWindowSize, clientNoContext, clientWindowSize);
+        } else {
+            return null;
+        }
+    }
+
+    private static class PermessageDeflateExtension implements WebSocketServerExtension {
+
+        private final int compressionLevel;
+        private final boolean serverNoContext;
+        private final int serverWindowSize;
+        private final boolean clientNoContext;
+        private final int clientWindowSize;
+
+        public PermessageDeflateExtension(int compressionLevel, boolean serverNoContext,
+                int serverWindowSize, boolean clientNoContext, int clientWindowSize) {
+            this.compressionLevel = compressionLevel;
+            this.serverNoContext = serverNoContext;
+            this.serverWindowSize = serverWindowSize;
+            this.clientNoContext = clientNoContext;
+            this.clientWindowSize = clientWindowSize;
+        }
+
+        @Override
+        public int rsv() {
+            return RSV1;
+        }
+
+        @Override
+        public WebSocketExtensionEncoder newExtensionEncoder() {
+            return new PerMessageDeflateEncoder(compressionLevel, clientWindowSize, clientNoContext);
+        }
+
+        @Override
+        public WebSocketExtensionDecoder newExtensionDecoder() {
+            return new PerMessageDeflateDecoder(serverNoContext);
+        }
+
+        @Override
+        public WebSocketExtensionData newReponseData() {
+            HashMap<String, String> parameters = new HashMap<String, String>(4);
+            if (serverNoContext) {
+                parameters.put(SERVER_NO_CONTEXT, null);
+            }
+            if (clientNoContext) {
+                parameters.put(CLIENT_NO_CONTEXT, null);
+            }
+            if (serverWindowSize != MAX_WINDOW_SIZE) {
+                parameters.put(SERVER_MAX_WINDOW, Integer.toString(serverWindowSize));
+            }
+            if (clientWindowSize != MAX_WINDOW_SIZE) {
+                parameters.put(CLIENT_MAX_WINDOW, Integer.toString(clientWindowSize));
+            }
+            return new WebSocketExtensionData(PERMESSAGE_DEFLATE_EXTENSION, parameters);
+        }
+    }
+
+}

codec-http/src/main/java/io/netty/handler/codec/http/websocketx/extensions/compression/WebSocketClientCompressionHandler.java

@@ -0,0 +1,40 @@
+/*
+ * Copyright 2014 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.extensions.compression;
+
+import io.netty.handler.codec.http.websocketx.extensions.WebSocketClientExtensionHandler;
+import io.netty.handler.codec.http.websocketx.extensions.WebSocketClientExtensionHandshaker;
+
+import java.util.Arrays;
+
+/**
+ * Extends <tt>io.netty.handler.codec.http.websocketx.extensions.compression.WebSocketClientExtensionHandler</tt>
+ * to handle the most common WebSocket Compression Extensions.
+ *
+ * See <tt>io.netty.example.http.websocketx.client.WebSocketClient</tt> for usage.
+ */
+public class WebSocketClientCompressionHandler extends WebSocketClientExtensionHandler {
+
+    /**
+     * Constructor with default configuration.
+     */
+    public WebSocketClientCompressionHandler() {
+        super(new PerMessageDeflateClientExtensionHandshaker(),
+                new DeflateFrameClientExtensionHandshaker(false),
+                new DeflateFrameClientExtensionHandshaker(true));
+    }
+
+}

codec-http/src/main/java/io/netty/handler/codec/http/websocketx/extensions/compression/WebSocketServerCompressionHandler.java

@@ -0,0 +1,36 @@
+/*
+ * Copyright 2014 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.extensions.compression;
+
+import io.netty.handler.codec.http.websocketx.extensions.WebSocketServerExtensionHandler;
+
+/**
+ * Extends <tt>io.netty.handler.codec.http.websocketx.extensions.compression.WebSocketServerExtensionHandler</tt>
+ * to handle the most common WebSocket Compression Extensions.
+ *
+ * See <tt>io.netty.example.http.websocketx.html5.WebSocketServer</tt> for usage.
+ */
+public class WebSocketServerCompressionHandler extends WebSocketServerExtensionHandler {
+
+    /**
+     * Constructor with default configuration.
+     */
+    public WebSocketServerCompressionHandler() {
+        super(new PerMessageDeflateServerExtensionHandshaker(),
+                new DeflateFrameServerExtensionHandshaker());
+    }
+
+}

codec-http/src/main/java/io/netty/handler/codec/http/websocketx/extensions/compression/package-info.java

@@ -0,0 +1,33 @@
+/*
+ * Copyright 2014 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.
+ */
+
+/**
+ * Encoder, decoder, handshakers to handle most common WebSocket Compression Extensions.
+ * <p>
+ * This package supports different web socket extensions.
+ * The specification currently supported are:
+ * <ul>
+ * <li><a href="http://tools.ietf.org/html/draft-ietf-hybi-permessage-compression-18">permessage-deflate</a></li>
+ * <li><a href="https://tools.ietf.org/id/draft-tyoshino-hybi-websocket-perframe-deflate-06.txt">
+ * perframe-deflate and x-webkit-deflate-frame</a></li>
+ * </ul>
+ * </p>
+ * <p>
+ * See <tt>io.netty.example.http.websocketx.client.WebSocketClient</tt> and
+ * <tt>io.netty.example.http.websocketx.html5.WebSocketServer</tt> for usage.
+ * </p>
+ */
+package io.netty.handler.codec.http.websocketx.extensions.compression;

codec-http/src/main/java/io/netty/handler/codec/http/websocketx/extensions/package-info.java

@@ -0,0 +1,23 @@
+/*
+ * Copyright 2014 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.
+ */
+
+/**
+ * Encoder, decoder, handshakers to handle
+ * <a href="http://tools.ietf.org/html/rfc6455#section-9.1">WebSocket Extensions</a>.
+ *
+ * See <tt>WebSocketServerExtensionHandler</tt> for more details.
+ */
+package io.netty.handler.codec.http.websocketx.extensions;

codec-http/src/test/java/io/netty/handler/codec/http/websocketx/extensions/WebSocketClientExtensionHandlerTest.java

@@ -0,0 +1,253 @@
+/*
+ * Copyright 2014 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.extensions;
+
+import static io.netty.handler.codec.http.websocketx.extensions.WebSocketExtensionTestUtil.*;
+import static org.easymock.EasyMock.*;
+import static org.junit.Assert.*;
+import io.netty.channel.ChannelHandlerContext;
+import io.netty.channel.embedded.EmbeddedChannel;
+import io.netty.handler.codec.CodecException;
+import io.netty.handler.codec.http.HttpHeaders.Names;
+import io.netty.handler.codec.http.HttpRequest;
+import io.netty.handler.codec.http.HttpResponse;
+import io.netty.handler.codec.http.websocketx.WebSocketFrame;
+
+import java.util.Collections;
+import java.util.List;
+
+import org.junit.Test;
+
+public class WebSocketClientExtensionHandlerTest {
+
+    WebSocketClientExtensionHandshaker mainHandshakerMock =
+            createMock("mainHandshaker", WebSocketClientExtensionHandshaker.class);
+    WebSocketClientExtensionHandshaker fallbackHandshakerMock =
+            createMock("fallbackHandshaker", WebSocketClientExtensionHandshaker.class);
+    WebSocketClientExtension mainExtensionMock =
+            createMock("mainExtension", WebSocketClientExtension.class);
+    WebSocketClientExtension fallbackExtensionMock =
+            createMock("fallbackExtension", WebSocketClientExtension.class);
+
+    @Test
+    public void testMainSuccess() {
+        // initialize
+        expect(mainHandshakerMock.newRequestData()).
+                andReturn(new WebSocketExtensionData("main", Collections.<String, String>emptyMap())).once();
+        expect(mainHandshakerMock.handshakeExtension(
+                anyObject(WebSocketExtensionData.class))).andReturn(mainExtensionMock).once();
+        replay(mainHandshakerMock);
+
+        expect(fallbackHandshakerMock.newRequestData()).
+                andReturn(new WebSocketExtensionData("fallback", Collections.<String, String>emptyMap())).once();
+        replay(fallbackHandshakerMock);
+
+        expect(mainExtensionMock.rsv()).andReturn(WebSocketExtension.RSV1).anyTimes();
+        expect(mainExtensionMock.newExtensionEncoder()).andReturn(new DummyEncoder()).once();
+        expect(mainExtensionMock.newExtensionDecoder()).andReturn(new DummyDecoder()).once();
+        replay(mainExtensionMock);
+
+        // execute
+        EmbeddedChannel ch = new EmbeddedChannel(new WebSocketClientExtensionHandler(
+                mainHandshakerMock, fallbackHandshakerMock));
+
+        HttpRequest req = newUpgradeRequest(null);
+        ch.writeOutbound(req);
+
+        HttpRequest req2 = ch.readOutbound();
+        List<WebSocketExtensionData> reqExts = WebSocketExtensionUtil.extractExtensions(
+                req2.headers().get(Names.SEC_WEBSOCKET_EXTENSIONS));
+
+        HttpResponse res = newUpgradeResponse("main");
+        ch.writeInbound(res);
+
+        HttpResponse res2 = ch.readInbound();
+        List<WebSocketExtensionData> resExts = WebSocketExtensionUtil.extractExtensions(
+                res2.headers().get(Names.SEC_WEBSOCKET_EXTENSIONS));
+
+        // test
+        assertEquals(2, reqExts.size());
+        assertEquals("main", reqExts.get(0).name());
+        assertEquals("fallback", reqExts.get(1).name());
+
+        assertEquals(1, resExts.size());
+        assertEquals("main", resExts.get(0).name());
+        assertTrue(resExts.get(0).parameters().isEmpty());
+        assertTrue(ch.pipeline().get(DummyDecoder.class) != null);
+        assertTrue(ch.pipeline().get(DummyEncoder.class) != null);
+    }
+
+    @Test
+    public void testFallbackSuccess() {
+        // initialize
+        expect(mainHandshakerMock.newRequestData()).
+                andReturn(new WebSocketExtensionData("main", Collections.<String, String>emptyMap())).once();
+        expect(mainHandshakerMock.handshakeExtension(
+                anyObject(WebSocketExtensionData.class))).andReturn(null).once();
+        replay(mainHandshakerMock);
+
+        expect(fallbackHandshakerMock.newRequestData()).
+                andReturn(new WebSocketExtensionData("fallback", Collections.<String, String>emptyMap())).once();
+        expect(fallbackHandshakerMock.handshakeExtension(
+                anyObject(WebSocketExtensionData.class))).andReturn(fallbackExtensionMock).once();
+        replay(fallbackHandshakerMock);
+
+        expect(fallbackExtensionMock.rsv()).andReturn(WebSocketExtension.RSV1).anyTimes();
+        expect(fallbackExtensionMock.newExtensionEncoder()).andReturn(new DummyEncoder()).once();
+        expect(fallbackExtensionMock.newExtensionDecoder()).andReturn(new DummyDecoder()).once();
+        replay(fallbackExtensionMock);
+
+        // execute
+        EmbeddedChannel ch = new EmbeddedChannel(new WebSocketClientExtensionHandler(
+                mainHandshakerMock, fallbackHandshakerMock));
+
+        HttpRequest req = newUpgradeRequest(null);
+        ch.writeOutbound(req);
+
+        HttpRequest req2 = ch.readOutbound();
+        List<WebSocketExtensionData> reqExts = WebSocketExtensionUtil.extractExtensions(
+                req2.headers().get(Names.SEC_WEBSOCKET_EXTENSIONS));
+
+        HttpResponse res = newUpgradeResponse("fallback");
+        ch.writeInbound(res);
+
+        HttpResponse res2 = ch.readInbound();
+        List<WebSocketExtensionData> resExts = WebSocketExtensionUtil.extractExtensions(
+                res2.headers().get(Names.SEC_WEBSOCKET_EXTENSIONS));
+
+        // test
+        assertEquals(2, reqExts.size());
+        assertEquals("main", reqExts.get(0).name());
+        assertEquals("fallback", reqExts.get(1).name());
+
+        assertEquals(1, resExts.size());
+        assertEquals("fallback", resExts.get(0).name());
+        assertTrue(resExts.get(0).parameters().isEmpty());
+        assertTrue(ch.pipeline().get(DummyDecoder.class) != null);
+        assertTrue(ch.pipeline().get(DummyEncoder.class) != null);
+    }
+
+    @Test
+    public void testAllSuccess() {
+        // initialize
+        expect(mainHandshakerMock.newRequestData()).
+                andReturn(new WebSocketExtensionData("main", Collections.<String, String>emptyMap())).once();
+        expect(mainHandshakerMock.handshakeExtension(
+                webSocketExtensionDataEqual("main"))).andReturn(mainExtensionMock).anyTimes();
+        expect(mainHandshakerMock.handshakeExtension(
+                webSocketExtensionDataEqual("fallback"))).andReturn(null).anyTimes();
+        replay(mainHandshakerMock);
+
+        expect(fallbackHandshakerMock.newRequestData()).
+                andReturn(new WebSocketExtensionData("fallback", Collections.<String, String>emptyMap())).once();
+        expect(fallbackHandshakerMock.handshakeExtension(
+                webSocketExtensionDataEqual("main"))).andReturn(null).anyTimes();
+        expect(fallbackHandshakerMock.handshakeExtension(
+                webSocketExtensionDataEqual("fallback"))).andReturn(fallbackExtensionMock).anyTimes();
+        replay(fallbackHandshakerMock);
+
+        DummyEncoder mainEncoder = new DummyEncoder();
+        DummyDecoder mainDecoder = new DummyDecoder();
+        expect(mainExtensionMock.rsv()).andReturn(WebSocketExtension.RSV1).anyTimes();
+        expect(mainExtensionMock.newExtensionEncoder()).andReturn(mainEncoder).once();
+        expect(mainExtensionMock.newExtensionDecoder()).andReturn(mainDecoder).once();
+        replay(mainExtensionMock);
+
+        Dummy2Encoder fallbackEncoder = new Dummy2Encoder();
+        Dummy2Decoder fallbackDecoder = new Dummy2Decoder();
+        expect(fallbackExtensionMock.rsv()).andReturn(WebSocketExtension.RSV2).anyTimes();
+        expect(fallbackExtensionMock.newExtensionEncoder()).andReturn(fallbackEncoder).once();
+        expect(fallbackExtensionMock.newExtensionDecoder()).andReturn(fallbackDecoder).once();
+        replay(fallbackExtensionMock);
+
+        // execute
+        EmbeddedChannel ch = new EmbeddedChannel(new WebSocketClientExtensionHandler(
+                mainHandshakerMock, fallbackHandshakerMock));
+
+        HttpRequest req = newUpgradeRequest(null);
+        ch.writeOutbound(req);
+
+        HttpRequest req2 = ch.readOutbound();
+        List<WebSocketExtensionData> reqExts = WebSocketExtensionUtil.extractExtensions(
+                req2.headers().get(Names.SEC_WEBSOCKET_EXTENSIONS));
+
+        HttpResponse res = newUpgradeResponse("main, fallback");
+        ch.writeInbound(res);
+
+        HttpResponse res2 = ch.readInbound();
+        List<WebSocketExtensionData> resExts = WebSocketExtensionUtil.extractExtensions(
+                res2.headers().get(Names.SEC_WEBSOCKET_EXTENSIONS));
+
+        // test
+        assertEquals(2, reqExts.size());
+        assertEquals("main", reqExts.get(0).name());
+        assertEquals("fallback", reqExts.get(1).name());
+
+        assertEquals(2, resExts.size());
+        assertEquals("main", resExts.get(0).name());
+        assertEquals("fallback", resExts.get(1).name());
+        assertTrue(ch.pipeline().context(mainEncoder) != null);
+        assertTrue(ch.pipeline().context(mainDecoder) != null);
+        assertTrue(ch.pipeline().context(fallbackEncoder) != null);
+        assertTrue(ch.pipeline().context(fallbackDecoder) != null);
+    }
+
+    @Test(expected = CodecException.class)
+    public void testIfMainAndFallbackUseRSV1WillFail() {
+        // initialize
+        expect(mainHandshakerMock.newRequestData()).
+                andReturn(new WebSocketExtensionData("main", Collections.<String, String>emptyMap())).once();
+        expect(mainHandshakerMock.handshakeExtension(
+                webSocketExtensionDataEqual("main"))).andReturn(mainExtensionMock).anyTimes();
+        expect(mainHandshakerMock.handshakeExtension(
+                webSocketExtensionDataEqual("fallback"))).andReturn(null).anyTimes();
+        replay(mainHandshakerMock);
+
+        expect(fallbackHandshakerMock.newRequestData()).
+                andReturn(new WebSocketExtensionData("fallback", Collections.<String, String>emptyMap())).once();
+        expect(fallbackHandshakerMock.handshakeExtension(
+                webSocketExtensionDataEqual("main"))).andReturn(null).anyTimes();
+        expect(fallbackHandshakerMock.handshakeExtension(
+                webSocketExtensionDataEqual("fallback"))).andReturn(fallbackExtensionMock).anyTimes();
+        replay(fallbackHandshakerMock);
+
+        expect(mainExtensionMock.rsv()).andReturn(WebSocketExtension.RSV1).anyTimes();
+        replay(mainExtensionMock);
+
+        expect(fallbackExtensionMock.rsv()).andReturn(WebSocketExtension.RSV1).anyTimes();
+        replay(fallbackExtensionMock);
+
+        // execute
+        EmbeddedChannel ch = new EmbeddedChannel(new WebSocketClientExtensionHandler(
+                mainHandshakerMock, fallbackHandshakerMock));
+
+        HttpRequest req = newUpgradeRequest(null);
+        ch.writeOutbound(req);
+
+        HttpRequest req2 = ch.readOutbound();
+        List<WebSocketExtensionData> reqExts = WebSocketExtensionUtil.extractExtensions(
+                req2.headers().get(Names.SEC_WEBSOCKET_EXTENSIONS));
+
+        HttpResponse res = newUpgradeResponse("main, fallback");
+        ch.writeInbound(res);
+
+        // test
+        assertEquals(2, reqExts.size());
+        assertEquals("main", reqExts.get(0).name());
+        assertEquals("fallback", reqExts.get(1).name());
+    }
+
+}

codec-http/src/test/java/io/netty/handler/codec/http/websocketx/extensions/WebSocketExtensionTestUtil.java

@@ -0,0 +1,129 @@
+/*
+ * 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 io.netty.handler.codec.http.websocketx.extensions;
+
+import java.util.List;
+
+import org.easymock.EasyMock;
+import org.easymock.IArgumentMatcher;
+
+import io.netty.channel.ChannelHandlerContext;
+import io.netty.handler.codec.http.DefaultHttpRequest;
+import io.netty.handler.codec.http.DefaultHttpResponse;
+import io.netty.handler.codec.http.HttpHeaders.Names;
+import io.netty.handler.codec.http.HttpHeaders.Values;
+import io.netty.handler.codec.http.websocketx.WebSocketFrame;
+import io.netty.handler.codec.http.HttpMethod;
+import io.netty.handler.codec.http.HttpRequest;
+import io.netty.handler.codec.http.HttpResponse;
+import io.netty.handler.codec.http.HttpResponseStatus;
+import io.netty.handler.codec.http.HttpVersion;
+import io.netty.util.ReferenceCountUtil;
+
+public final class WebSocketExtensionTestUtil {
+
+    public static HttpRequest newUpgradeRequest(String ext) {
+        HttpRequest req = ReferenceCountUtil.releaseLater(new DefaultHttpRequest(
+                HttpVersion.HTTP_1_1, HttpMethod.GET, "/chat"));
+
+        req.headers().set(Names.HOST, "server.example.com");
+        req.headers().set(Names.UPGRADE, Values.WEBSOCKET.toString().toLowerCase());
+        req.headers().set(Names.CONNECTION, "Upgrade");
+        req.headers().set(Names.ORIGIN, "http://example.com");
+        if (ext != null) {
+            req.headers().set(Names.SEC_WEBSOCKET_EXTENSIONS, ext);
+        }
+
+        return req;
+    }
+
+    public static HttpResponse newUpgradeResponse(String ext) {
+        HttpResponse res = ReferenceCountUtil.releaseLater(new DefaultHttpResponse(
+                HttpVersion.HTTP_1_1, HttpResponseStatus.SWITCHING_PROTOCOLS));
+
+        res.headers().set(Names.HOST, "server.example.com");
+        res.headers().set(Names.UPGRADE, Values.WEBSOCKET.toString().toLowerCase());
+        res.headers().set(Names.CONNECTION, "Upgrade");
+        res.headers().set(Names.ORIGIN, "http://example.com");
+        if (ext != null) {
+            res.headers().set(Names.SEC_WEBSOCKET_EXTENSIONS, ext);
+        }
+
+        return res;
+    }
+
+    public static WebSocketExtensionData webSocketExtensionDataEqual(String name) {
+        EasyMock.reportMatcher(new WebSocketExtensionDataMatcher(name));
+        return null;
+    }
+
+    public static class WebSocketExtensionDataMatcher implements IArgumentMatcher {
+
+        private final String name;
+
+        public WebSocketExtensionDataMatcher(String name) {
+            this.name = name;
+        }
+
+        @Override
+        public void appendTo(StringBuffer buf) {
+            buf.append("WebSocketExtensionData with name=" + name);
+        }
+
+        @Override
+        public boolean matches(Object o) {
+            return o instanceof WebSocketExtensionData &&
+                    name.equals(((WebSocketExtensionData) o).name());
+        }
+    }
+
+    private WebSocketExtensionTestUtil() {
+        // unused
+    }
+
+    static class DummyEncoder extends WebSocketExtensionEncoder {
+        @Override
+        protected void encode(ChannelHandlerContext ctx, WebSocketFrame msg,
+                List<Object> out) throws Exception {
+            // unused
+        }
+    }
+
+    static class DummyDecoder extends WebSocketExtensionDecoder {
+        @Override
+        protected void decode(ChannelHandlerContext ctx, WebSocketFrame msg,
+                List<Object> out) throws Exception {
+            // unused
+        }
+    }
+
+    static class Dummy2Encoder extends WebSocketExtensionEncoder {
+        @Override
+        protected void encode(ChannelHandlerContext ctx, WebSocketFrame msg,
+                List<Object> out) throws Exception {
+            // unused
+        }
+    }
+
+    static class Dummy2Decoder extends WebSocketExtensionDecoder {
+        @Override
+        protected void decode(ChannelHandlerContext ctx, WebSocketFrame msg,
+                List<Object> out) throws Exception {
+            // unused
+        }
+    }
+
+}

codec-http/src/test/java/io/netty/handler/codec/http/websocketx/extensions/WebSocketServerExtensionHandlerTest.java

@@ -0,0 +1,176 @@
+/*
+ * Copyright 2014 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.extensions;
+
+import static io.netty.handler.codec.http.websocketx.extensions.WebSocketExtensionTestUtil.*;
+import static org.easymock.EasyMock.*;
+import static org.junit.Assert.*;
+import io.netty.channel.ChannelHandlerContext;
+import io.netty.channel.embedded.EmbeddedChannel;
+import io.netty.handler.codec.CodecException;
+import io.netty.handler.codec.http.HttpHeaders.Names;
+import io.netty.handler.codec.http.HttpRequest;
+import io.netty.handler.codec.http.HttpResponse;
+import io.netty.handler.codec.http.websocketx.WebSocketFrame;
+
+import java.util.Collections;
+import java.util.List;
+
+import org.junit.Test;
+
+public class WebSocketServerExtensionHandlerTest {
+
+    WebSocketServerExtensionHandshaker mainHandshakerMock =
+            createMock("mainHandshaker", WebSocketServerExtensionHandshaker.class);
+    WebSocketServerExtensionHandshaker fallbackHandshakerMock =
+            createMock("fallbackHandshaker", WebSocketServerExtensionHandshaker.class);
+    WebSocketServerExtension mainExtensionMock =
+            createMock("mainExtension", WebSocketServerExtension.class);
+    WebSocketServerExtension fallbackExtensionMock =
+            createMock("fallbackExtension", WebSocketServerExtension.class);
+
+    @Test
+    public void testMainSuccess() {
+        // initialize
+        expect(mainHandshakerMock.handshakeExtension(webSocketExtensionDataEqual("main"))).
+                andReturn(mainExtensionMock).anyTimes();
+        expect(mainHandshakerMock.handshakeExtension(webSocketExtensionDataEqual("fallback"))).
+                andReturn(null).anyTimes();
+        replay(mainHandshakerMock);
+
+        expect(fallbackHandshakerMock.handshakeExtension(webSocketExtensionDataEqual("fallback"))).
+                andReturn(fallbackExtensionMock).anyTimes();
+        expect(fallbackHandshakerMock.handshakeExtension(webSocketExtensionDataEqual("main"))).
+                andReturn(null).anyTimes();
+        replay(fallbackHandshakerMock);
+
+        expect(mainExtensionMock.rsv()).andReturn(WebSocketExtension.RSV1).anyTimes();
+        expect(mainExtensionMock.newReponseData()).andReturn(
+                new WebSocketExtensionData("main", Collections.<String, String>emptyMap())).once();
+        expect(mainExtensionMock.newExtensionEncoder()).andReturn(new DummyEncoder()).once();
+        expect(mainExtensionMock.newExtensionDecoder()).andReturn(new DummyDecoder()).once();
+        replay(mainExtensionMock);
+
+        expect(fallbackExtensionMock.rsv()).andReturn(WebSocketExtension.RSV1).anyTimes();
+        replay(fallbackExtensionMock);
+
+        // execute
+        EmbeddedChannel ch = new EmbeddedChannel(new WebSocketServerExtensionHandler(
+                mainHandshakerMock, fallbackHandshakerMock));
+
+        HttpRequest req = newUpgradeRequest("main, fallback");
+        ch.writeInbound(req);
+
+        HttpResponse res = newUpgradeResponse(null);
+        ch.writeOutbound(res);
+
+        HttpResponse res2 = ch.readOutbound();
+        List<WebSocketExtensionData> resExts = WebSocketExtensionUtil.extractExtensions(
+                res2.headers().get(Names.SEC_WEBSOCKET_EXTENSIONS));
+
+        // test
+        assertEquals(1, resExts.size());
+        assertEquals("main", resExts.get(0).name());
+        assertTrue(resExts.get(0).parameters().isEmpty());
+        assertTrue(ch.pipeline().get(DummyDecoder.class) != null);
+        assertTrue(ch.pipeline().get(DummyEncoder.class) != null);
+    }
+
+    @Test
+    public void testCompatibleExtensionTogetherSuccess() {
+        // initialize
+        expect(mainHandshakerMock.handshakeExtension(webSocketExtensionDataEqual("main"))).
+                andReturn(mainExtensionMock).anyTimes();
+        expect(mainHandshakerMock.handshakeExtension(webSocketExtensionDataEqual("fallback"))).
+                andReturn(null).anyTimes();
+        replay(mainHandshakerMock);
+
+        expect(fallbackHandshakerMock.handshakeExtension(webSocketExtensionDataEqual("fallback"))).
+                andReturn(fallbackExtensionMock).anyTimes();
+        expect(fallbackHandshakerMock.handshakeExtension(webSocketExtensionDataEqual("main"))).
+                andReturn(null).anyTimes();
+        replay(fallbackHandshakerMock);
+
+        expect(mainExtensionMock.rsv()).andReturn(WebSocketExtension.RSV1).anyTimes();
+        expect(mainExtensionMock.newReponseData()).andReturn(
+                new WebSocketExtensionData("main", Collections.<String, String>emptyMap())).once();
+        expect(mainExtensionMock.newExtensionEncoder()).andReturn(new DummyEncoder()).once();
+        expect(mainExtensionMock.newExtensionDecoder()).andReturn(new DummyDecoder()).once();
+        replay(mainExtensionMock);
+
+        expect(fallbackExtensionMock.rsv()).andReturn(WebSocketExtension.RSV2).anyTimes();
+        expect(fallbackExtensionMock.newReponseData()).andReturn(
+                new WebSocketExtensionData("fallback", Collections.<String, String>emptyMap())).once();
+        expect(fallbackExtensionMock.newExtensionEncoder()).andReturn(new Dummy2Encoder()).once();
+        expect(fallbackExtensionMock.newExtensionDecoder()).andReturn(new Dummy2Decoder()).once();
+        replay(fallbackExtensionMock);
+
+        // execute
+        EmbeddedChannel ch = new EmbeddedChannel(new WebSocketServerExtensionHandler(
+                mainHandshakerMock, fallbackHandshakerMock));
+
+        HttpRequest req = newUpgradeRequest("main, fallback");
+        ch.writeInbound(req);
+
+        HttpResponse res = newUpgradeResponse(null);
+        ch.writeOutbound(res);
+
+        HttpResponse res2 = ch.readOutbound();
+        List<WebSocketExtensionData> resExts = WebSocketExtensionUtil.extractExtensions(
+                res2.headers().get(Names.SEC_WEBSOCKET_EXTENSIONS));
+
+        // test
+        assertEquals(2, resExts.size());
+        assertEquals("main", resExts.get(0).name());
+        assertEquals("fallback", resExts.get(1).name());
+        assertTrue(ch.pipeline().get(DummyDecoder.class) != null);
+        assertTrue(ch.pipeline().get(DummyEncoder.class) != null);
+        assertTrue(ch.pipeline().get(Dummy2Decoder.class) != null);
+        assertTrue(ch.pipeline().get(Dummy2Encoder.class) != null);
+    }
+
+    @Test
+    public void testNoneExtensionMatchingSuccess() {
+        // initialize
+        expect(mainHandshakerMock.handshakeExtension(webSocketExtensionDataEqual("unknown"))).
+                andReturn(null).anyTimes();
+        expect(mainHandshakerMock.handshakeExtension(webSocketExtensionDataEqual("unknown2"))).
+                andReturn(null).anyTimes();
+        replay(mainHandshakerMock);
+
+        expect(fallbackHandshakerMock.handshakeExtension(webSocketExtensionDataEqual("unknown"))).
+                andReturn(null).anyTimes();
+        expect(fallbackHandshakerMock.handshakeExtension(webSocketExtensionDataEqual("unknown2"))).
+                andReturn(null).anyTimes();
+        replay(fallbackHandshakerMock);
+
+        // execute
+        EmbeddedChannel ch = new EmbeddedChannel(new WebSocketServerExtensionHandler(
+                mainHandshakerMock, fallbackHandshakerMock));
+
+        HttpRequest req = newUpgradeRequest("unknown, unknown2");
+        ch.writeInbound(req);
+
+        HttpResponse res = newUpgradeResponse(null);
+        ch.writeOutbound(res);
+
+        HttpResponse res2 = ch.readOutbound();
+
+        // test
+        assertFalse(res2.headers().contains(Names.SEC_WEBSOCKET_EXTENSIONS));
+    }
+
+}

codec-http/src/test/java/io/netty/handler/codec/http/websocketx/extensions/compression/DeflateFrameClientExtensionHandshakerTest.java

@@ -0,0 +1,84 @@
+/*
+ * Copyright 2014 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.extensions.compression;
+
+import static io.netty.handler.codec.http.websocketx.extensions.compression.
+        DeflateFrameServerExtensionHandshaker.*;
+import static org.junit.Assert.*;
+import io.netty.handler.codec.http.websocketx.extensions.WebSocketClientExtension;
+import io.netty.handler.codec.http.websocketx.extensions.WebSocketExtensionData;
+
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.Map;
+
+import org.junit.Test;
+
+public class DeflateFrameClientExtensionHandshakerTest {
+
+    @Test
+    public void testWebkitDeflateFrameData() {
+        DeflateFrameClientExtensionHandshaker handshaker =
+                new DeflateFrameClientExtensionHandshaker(true);
+
+        WebSocketExtensionData data = handshaker.newRequestData();
+
+        assertEquals(X_WEBKIT_DEFLATE_FRAME_EXTENSION, data.name());
+        assertTrue(data.parameters().isEmpty());
+    }
+
+    @Test
+    public void testDeflateFrameData() {
+        DeflateFrameClientExtensionHandshaker handshaker =
+                new DeflateFrameClientExtensionHandshaker(false);
+
+        WebSocketExtensionData data = handshaker.newRequestData();
+
+        assertEquals(DEFLATE_FRAME_EXTENSION, data.name());
+        assertTrue(data.parameters().isEmpty());
+    }
+
+    @Test
+    public void testNormalHandshake() {
+        DeflateFrameClientExtensionHandshaker handshaker =
+                new DeflateFrameClientExtensionHandshaker(false);
+
+        WebSocketClientExtension extension = handshaker.handshakeExtension(
+                new WebSocketExtensionData(DEFLATE_FRAME_EXTENSION, Collections.<String, String>emptyMap()));
+
+        assertNotNull(extension);
+        assertEquals(WebSocketClientExtension.RSV1, extension.rsv());
+        assertTrue(extension.newExtensionDecoder() instanceof PerFrameDeflateDecoder);
+        assertTrue(extension.newExtensionEncoder() instanceof PerFrameDeflateEncoder);
+    }
+
+    @Test
+    public void testFailedHandshake() {
+        // initialize
+        DeflateFrameClientExtensionHandshaker handshaker =
+                new DeflateFrameClientExtensionHandshaker(false);
+
+        Map<String, String> parameters = new HashMap<String, String>();
+        parameters.put("invalid", "12");
+
+        // execute
+        WebSocketClientExtension extension = handshaker.handshakeExtension(
+                new WebSocketExtensionData(DEFLATE_FRAME_EXTENSION, parameters));
+
+        // test
+        assertNull(extension);
+    }
+}

codec-http/src/test/java/io/netty/handler/codec/http/websocketx/extensions/compression/DeflateFrameServerExtensionHandshakerTest.java

@@ -0,0 +1,84 @@
+/*
+ * Copyright 2014 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.extensions.compression;
+
+import static io.netty.handler.codec.http.websocketx.extensions.compression.
+        DeflateFrameServerExtensionHandshaker.*;
+import static org.junit.Assert.*;
+import io.netty.handler.codec.http.websocketx.extensions.WebSocketServerExtension;
+import io.netty.handler.codec.http.websocketx.extensions.WebSocketExtensionData;
+
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.Map;
+
+import org.junit.Test;
+
+public class DeflateFrameServerExtensionHandshakerTest {
+
+    @Test
+    public void testNormalHandshake() {
+        // initialize
+        DeflateFrameServerExtensionHandshaker handshaker =
+                new DeflateFrameServerExtensionHandshaker();
+
+        // execute
+        WebSocketServerExtension extension = handshaker.handshakeExtension(
+                new WebSocketExtensionData(DEFLATE_FRAME_EXTENSION, Collections.<String, String>emptyMap()));
+
+        // test
+        assertNotNull(extension);
+        assertEquals(WebSocketServerExtension.RSV1, extension.rsv());
+        assertTrue(extension.newExtensionDecoder() instanceof PerFrameDeflateDecoder);
+        assertTrue(extension.newExtensionEncoder() instanceof PerFrameDeflateEncoder);
+    }
+
+    @Test
+    public void testWebkitHandshake() {
+        // initialize
+        DeflateFrameServerExtensionHandshaker handshaker =
+                new DeflateFrameServerExtensionHandshaker();
+
+        // execute
+        WebSocketServerExtension extension = handshaker.handshakeExtension(
+                new WebSocketExtensionData(X_WEBKIT_DEFLATE_FRAME_EXTENSION, Collections.<String, String>emptyMap()));
+
+        // test
+        assertNotNull(extension);
+        assertEquals(WebSocketServerExtension.RSV1, extension.rsv());
+        assertTrue(extension.newExtensionDecoder() instanceof PerFrameDeflateDecoder);
+        assertTrue(extension.newExtensionEncoder() instanceof PerFrameDeflateEncoder);
+    }
+
+    @Test
+    public void testFailedHandshake() {
+        // initialize
+        DeflateFrameServerExtensionHandshaker handshaker =
+                new DeflateFrameServerExtensionHandshaker();
+
+        Map<String, String> parameters;
+        parameters = new HashMap<String, String>();
+        parameters.put("unknown", "11");
+
+        // execute
+        WebSocketServerExtension extension = handshaker.handshakeExtension(
+                new WebSocketExtensionData(DEFLATE_FRAME_EXTENSION, parameters));
+
+        // test
+        assertNull(extension);
+    }
+
+}

codec-http/src/test/java/io/netty/handler/codec/http/websocketx/extensions/compression/PerFrameDeflateDecoderTest.java

@@ -0,0 +1,123 @@
+/*
+ * Copyright 2014 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.extensions.compression;
+
+import static org.junit.Assert.*;
+import io.netty.buffer.ByteBuf;
+import io.netty.buffer.Unpooled;
+import io.netty.channel.embedded.EmbeddedChannel;
+import io.netty.handler.codec.compression.ZlibCodecFactory;
+import io.netty.handler.codec.compression.ZlibWrapper;
+import io.netty.handler.codec.http.websocketx.BinaryWebSocketFrame;
+import io.netty.handler.codec.http.websocketx.extensions.WebSocketExtension;
+
+import java.util.Arrays;
+import java.util.Random;
+
+import org.junit.Test;
+
+public class PerFrameDeflateDecoderTest {
+
+    private static final Random random = new Random();
+
+    @Test
+    public void testCompressedFrame() {
+        EmbeddedChannel encoderChannel = new EmbeddedChannel(
+                ZlibCodecFactory.newZlibEncoder(ZlibWrapper.NONE, 9, 15, 8));
+        EmbeddedChannel decoderChannel = new EmbeddedChannel(new PerFrameDeflateDecoder(false));
+
+        // initialize
+        byte[] payload = new byte[300];
+        random.nextBytes(payload);
+
+        encoderChannel.writeOutbound(Unpooled.wrappedBuffer(payload));
+        ByteBuf compressedPayload = encoderChannel.readOutbound();
+
+        BinaryWebSocketFrame compressedFrame = new BinaryWebSocketFrame(true,
+                WebSocketExtension.RSV1 | WebSocketExtension.RSV3,
+                compressedPayload.slice(0, compressedPayload.readableBytes() - 4));
+
+        // execute
+        decoderChannel.writeInbound(compressedFrame);
+        BinaryWebSocketFrame uncompressedFrame = decoderChannel.readInbound();
+
+        // test
+        assertNotNull(uncompressedFrame);
+        assertNotNull(uncompressedFrame.content());
+        assertTrue(uncompressedFrame instanceof BinaryWebSocketFrame);
+        assertEquals(WebSocketExtension.RSV3, uncompressedFrame.rsv());
+        assertEquals(300, uncompressedFrame.content().readableBytes());
+
+        byte[] finalPayload = new byte[300];
+        uncompressedFrame.content().readBytes(finalPayload);
+        assertTrue(Arrays.equals(finalPayload, payload));
+        uncompressedFrame.release();
+    }
+
+    @Test
+    public void testNormalFrame() {
+        EmbeddedChannel decoderChannel = new EmbeddedChannel(new PerFrameDeflateDecoder(false));
+
+        // initialize
+        byte[] payload = new byte[300];
+        random.nextBytes(payload);
+
+        BinaryWebSocketFrame frame = new BinaryWebSocketFrame(true,
+                WebSocketExtension.RSV3, Unpooled.wrappedBuffer(payload));
+
+        // execute
+        decoderChannel.writeInbound(frame);
+        BinaryWebSocketFrame newFrame = decoderChannel.readInbound();
+
+        // test
+        assertNotNull(newFrame);
+        assertNotNull(newFrame.content());
+        assertTrue(newFrame instanceof BinaryWebSocketFrame);
+        assertEquals(WebSocketExtension.RSV3, newFrame.rsv());
+        assertEquals(300, newFrame.content().readableBytes());
+
+        byte[] finalPayload = new byte[300];
+        newFrame.content().readBytes(finalPayload);
+        assertTrue(Arrays.equals(finalPayload, payload));
+        newFrame.release();
+    }
+
+    // See https://github.com/netty/netty/issues/4348
+    @Test
+    public void testCompressedEmptyFrame() {
+        EmbeddedChannel encoderChannel = new EmbeddedChannel(
+                ZlibCodecFactory.newZlibEncoder(ZlibWrapper.NONE, 9, 15, 8));
+        EmbeddedChannel decoderChannel = new EmbeddedChannel(new PerFrameDeflateDecoder(false));
+
+        encoderChannel.writeOutbound(Unpooled.EMPTY_BUFFER);
+        ByteBuf compressedPayload = encoderChannel.readOutbound();
+        BinaryWebSocketFrame compressedFrame =
+                new BinaryWebSocketFrame(true, WebSocketExtension.RSV1 | WebSocketExtension.RSV3, compressedPayload);
+
+        // execute
+        decoderChannel.writeInbound(compressedFrame);
+        BinaryWebSocketFrame uncompressedFrame = decoderChannel.readInbound();
+
+        // test
+        assertNotNull(uncompressedFrame);
+        assertNotNull(uncompressedFrame.content());
+        assertTrue(uncompressedFrame instanceof BinaryWebSocketFrame);
+        assertEquals(WebSocketExtension.RSV3, uncompressedFrame.rsv());
+        assertEquals(0, uncompressedFrame.content().readableBytes());
+        uncompressedFrame.release();
+    }
+
+}

codec-http/src/test/java/io/netty/handler/codec/http/websocketx/extensions/compression/PerFrameDeflateEncoderTest.java

@@ -0,0 +1,162 @@
+/*
+ * Copyright 2014 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.extensions.compression;
+
+import static org.junit.Assert.*;
+import io.netty.buffer.ByteBuf;
+import io.netty.buffer.Unpooled;
+import io.netty.channel.embedded.EmbeddedChannel;
+import io.netty.handler.codec.compression.ZlibCodecFactory;
+import io.netty.handler.codec.compression.ZlibWrapper;
+import io.netty.handler.codec.http.websocketx.BinaryWebSocketFrame;
+import io.netty.handler.codec.http.websocketx.ContinuationWebSocketFrame;
+import io.netty.handler.codec.http.websocketx.extensions.WebSocketExtension;
+
+import java.util.Arrays;
+import java.util.Random;
+
+import org.junit.Test;
+
+public class PerFrameDeflateEncoderTest {
+
+    private static final Random random = new Random();
+
+    @Test
+    public void testCompressedFrame() {
+        EmbeddedChannel encoderChannel = new EmbeddedChannel(new PerFrameDeflateEncoder(9, 15, false));
+        EmbeddedChannel decoderChannel = new EmbeddedChannel(
+                ZlibCodecFactory.newZlibDecoder(ZlibWrapper.NONE));
+
+        // initialize
+        byte[] payload = new byte[300];
+        random.nextBytes(payload);
+        BinaryWebSocketFrame frame = new BinaryWebSocketFrame(true,
+                WebSocketExtension.RSV3, Unpooled.wrappedBuffer(payload));
+
+        // execute
+        encoderChannel.writeOutbound(frame);
+        BinaryWebSocketFrame compressedFrame = encoderChannel.readOutbound();
+
+        // test
+        assertNotNull(compressedFrame);
+        assertNotNull(compressedFrame.content());
+        assertTrue(compressedFrame instanceof BinaryWebSocketFrame);
+        assertEquals(WebSocketExtension.RSV1 | WebSocketExtension.RSV3, compressedFrame.rsv());
+
+        decoderChannel.writeInbound(compressedFrame.content());
+        decoderChannel.writeInbound(DeflateDecoder.FRAME_TAIL);
+        ByteBuf uncompressedPayload = decoderChannel.readInbound();
+        assertEquals(300, uncompressedPayload.readableBytes());
+
+        byte[] finalPayload = new byte[300];
+        uncompressedPayload.readBytes(finalPayload);
+        assertTrue(Arrays.equals(finalPayload, payload));
+        uncompressedPayload.release();
+    }
+
+    @Test
+    public void testAlreadyCompressedFrame() {
+        EmbeddedChannel encoderChannel = new EmbeddedChannel(new PerFrameDeflateEncoder(9, 15, false));
+
+        // initialize
+        byte[] payload = new byte[300];
+        random.nextBytes(payload);
+
+        BinaryWebSocketFrame frame = new BinaryWebSocketFrame(true,
+                WebSocketExtension.RSV3 | WebSocketExtension.RSV1, Unpooled.wrappedBuffer(payload));
+
+        // execute
+        encoderChannel.writeOutbound(frame);
+        BinaryWebSocketFrame newFrame = encoderChannel.readOutbound();
+
+        // test
+        assertNotNull(newFrame);
+        assertNotNull(newFrame.content());
+        assertTrue(newFrame instanceof BinaryWebSocketFrame);
+        assertEquals(WebSocketExtension.RSV3 | WebSocketExtension.RSV1, newFrame.rsv());
+        assertEquals(300, newFrame.content().readableBytes());
+
+        byte[] finalPayload = new byte[300];
+        newFrame.content().readBytes(finalPayload);
+        assertTrue(Arrays.equals(finalPayload, payload));
+        newFrame.release();
+    }
+
+    @Test
+    public void testFramementedFrame() {
+        EmbeddedChannel encoderChannel = new EmbeddedChannel(new PerFrameDeflateEncoder(9, 15, false));
+        EmbeddedChannel decoderChannel = new EmbeddedChannel(
+                ZlibCodecFactory.newZlibDecoder(ZlibWrapper.NONE));
+
+        // initialize
+        byte[] payload1 = new byte[100];
+        random.nextBytes(payload1);
+        byte[] payload2 = new byte[100];
+        random.nextBytes(payload2);
+        byte[] payload3 = new byte[100];
+        random.nextBytes(payload3);
+
+        BinaryWebSocketFrame frame1 = new BinaryWebSocketFrame(false,
+                WebSocketExtension.RSV3, Unpooled.wrappedBuffer(payload1));
+        ContinuationWebSocketFrame frame2 = new ContinuationWebSocketFrame(false,
+                WebSocketExtension.RSV3, Unpooled.wrappedBuffer(payload2));
+        ContinuationWebSocketFrame frame3 = new ContinuationWebSocketFrame(true,
+                WebSocketExtension.RSV3, Unpooled.wrappedBuffer(payload3));
+
+        // execute
+        encoderChannel.writeOutbound(frame1);
+        encoderChannel.writeOutbound(frame2);
+        encoderChannel.writeOutbound(frame3);
+        BinaryWebSocketFrame compressedFrame1 = encoderChannel.readOutbound();
+        ContinuationWebSocketFrame compressedFrame2 = encoderChannel.readOutbound();
+        ContinuationWebSocketFrame compressedFrame3 = encoderChannel.readOutbound();
+
+        // test
+        assertNotNull(compressedFrame1);
+        assertNotNull(compressedFrame2);
+        assertNotNull(compressedFrame3);
+        assertEquals(WebSocketExtension.RSV1 | WebSocketExtension.RSV3, compressedFrame1.rsv());
+        assertEquals(WebSocketExtension.RSV1 | WebSocketExtension.RSV3, compressedFrame2.rsv());
+        assertEquals(WebSocketExtension.RSV1 | WebSocketExtension.RSV3, compressedFrame3.rsv());
+        assertFalse(compressedFrame1.isFinalFragment());
+        assertFalse(compressedFrame2.isFinalFragment());
+        assertTrue(compressedFrame3.isFinalFragment());
+
+        decoderChannel.writeInbound(compressedFrame1.content());
+        decoderChannel.writeInbound(Unpooled.wrappedBuffer(DeflateDecoder.FRAME_TAIL));
+        ByteBuf uncompressedPayload1 = decoderChannel.readInbound();
+        byte[] finalPayload1 = new byte[100];
+        uncompressedPayload1.readBytes(finalPayload1);
+        assertTrue(Arrays.equals(finalPayload1, payload1));
+        uncompressedPayload1.release();
+
+        decoderChannel.writeInbound(compressedFrame2.content());
+        decoderChannel.writeInbound(Unpooled.wrappedBuffer(DeflateDecoder.FRAME_TAIL));
+        ByteBuf uncompressedPayload2 = decoderChannel.readInbound();
+        byte[] finalPayload2 = new byte[100];
+        uncompressedPayload2.readBytes(finalPayload2);
+        assertTrue(Arrays.equals(finalPayload2, payload2));
+        uncompressedPayload2.release();
+
+        decoderChannel.writeInbound(compressedFrame3.content());
+        decoderChannel.writeInbound(Unpooled.wrappedBuffer(DeflateDecoder.FRAME_TAIL));
+        ByteBuf uncompressedPayload3 = decoderChannel.readInbound();
+        byte[] finalPayload3 = new byte[100];
+        uncompressedPayload3.readBytes(finalPayload3);
+        assertTrue(Arrays.equals(finalPayload3, payload3));
+        uncompressedPayload3.release();
+    }
+}

codec-http/src/test/java/io/netty/handler/codec/http/websocketx/extensions/compression/PerMessageDeflateClientExtensionHandshakerTest.java

@@ -0,0 +1,122 @@
+/*
+ * Copyright 2014 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.extensions.compression;
+
+import static io.netty.handler.codec.http.websocketx.extensions.compression.
+        PerMessageDeflateServerExtensionHandshaker.*;
+import static org.junit.Assert.*;
+import io.netty.handler.codec.http.websocketx.extensions.WebSocketClientExtension;
+import io.netty.handler.codec.http.websocketx.extensions.WebSocketExtensionData;
+
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.Map;
+
+import org.junit.Test;
+
+public class PerMessageDeflateClientExtensionHandshakerTest {
+
+    @Test
+    public void testNormalData() {
+        PerMessageDeflateClientExtensionHandshaker handshaker =
+                new PerMessageDeflateClientExtensionHandshaker();
+
+        WebSocketExtensionData data = handshaker.newRequestData();
+
+        assertEquals(PERMESSAGE_DEFLATE_EXTENSION, data.name());
+        assertTrue(data.parameters().isEmpty());
+    }
+
+    @Test
+    public void testCustomData() {
+        PerMessageDeflateClientExtensionHandshaker handshaker =
+                new PerMessageDeflateClientExtensionHandshaker(6, true, 10, true, true);
+
+        WebSocketExtensionData data = handshaker.newRequestData();
+
+        assertEquals(PERMESSAGE_DEFLATE_EXTENSION, data.name());
+        assertTrue(data.parameters().containsKey(CLIENT_MAX_WINDOW));
+        assertTrue(data.parameters().containsKey(SERVER_MAX_WINDOW));
+        assertTrue(data.parameters().get(SERVER_MAX_WINDOW).equals("10"));
+        assertTrue(data.parameters().containsKey(CLIENT_MAX_WINDOW));
+        assertTrue(data.parameters().containsKey(SERVER_MAX_WINDOW));
+    }
+
+    @Test
+    public void testNormalHandshake() {
+        PerMessageDeflateClientExtensionHandshaker handshaker =
+                new PerMessageDeflateClientExtensionHandshaker();
+
+        WebSocketClientExtension extension = handshaker.handshakeExtension(
+                new WebSocketExtensionData(PERMESSAGE_DEFLATE_EXTENSION, Collections.<String, String>emptyMap()));
+
+        assertNotNull(extension);
+        assertEquals(WebSocketClientExtension.RSV1, extension.rsv());
+        assertTrue(extension.newExtensionDecoder() instanceof PerMessageDeflateDecoder);
+        assertTrue(extension.newExtensionEncoder() instanceof PerMessageDeflateEncoder);
+    }
+
+    @Test
+    public void testCustomHandshake() {
+        WebSocketClientExtension extension;
+        Map<String, String> parameters;
+
+        // initialize
+        PerMessageDeflateClientExtensionHandshaker handshaker =
+                new PerMessageDeflateClientExtensionHandshaker(6, true, 10, true, true);
+
+        parameters = new HashMap<String, String>();
+        parameters.put(CLIENT_MAX_WINDOW, "12");
+        parameters.put(SERVER_MAX_WINDOW, "10");
+        parameters.put(CLIENT_NO_CONTEXT, null);
+        parameters.put(SERVER_NO_CONTEXT, null);
+
+        // execute
+        extension = handshaker.handshakeExtension(
+                new WebSocketExtensionData(PERMESSAGE_DEFLATE_EXTENSION, parameters));
+
+        // test
+        assertNotNull(extension);
+        assertEquals(WebSocketClientExtension.RSV1, extension.rsv());
+        assertTrue(extension.newExtensionDecoder() instanceof PerMessageDeflateDecoder);
+        assertTrue(extension.newExtensionEncoder() instanceof PerMessageDeflateEncoder);
+
+        // initialize
+        parameters = new HashMap<String, String>();
+        parameters.put(SERVER_MAX_WINDOW, "10");
+        parameters.put(SERVER_NO_CONTEXT, null);
+
+        // execute
+        extension = handshaker.handshakeExtension(
+                new WebSocketExtensionData(PERMESSAGE_DEFLATE_EXTENSION, parameters));
+
+        // test
+        assertNotNull(extension);
+        assertEquals(WebSocketClientExtension.RSV1, extension.rsv());
+        assertTrue(extension.newExtensionDecoder() instanceof PerMessageDeflateDecoder);
+        assertTrue(extension.newExtensionEncoder() instanceof PerMessageDeflateEncoder);
+
+        // initialize
+        parameters = new HashMap<String, String>();
+
+        // execute
+        extension = handshaker.handshakeExtension(
+                new WebSocketExtensionData(PERMESSAGE_DEFLATE_EXTENSION, parameters));
+
+        // test
+        assertNull(extension);
+    }
+}

codec-http/src/test/java/io/netty/handler/codec/http/websocketx/extensions/compression/PerMessageDeflateDecoderTest.java

@@ -0,0 +1,194 @@
+/*
+ * Copyright 2014 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.extensions.compression;
+
+import static org.junit.Assert.*;
+import io.netty.buffer.ByteBuf;
+import io.netty.buffer.Unpooled;
+import io.netty.channel.embedded.EmbeddedChannel;
+import io.netty.handler.codec.compression.ZlibCodecFactory;
+import io.netty.handler.codec.compression.ZlibWrapper;
+import io.netty.handler.codec.http.websocketx.BinaryWebSocketFrame;
+import io.netty.handler.codec.http.websocketx.ContinuationWebSocketFrame;
+import io.netty.handler.codec.http.websocketx.extensions.WebSocketExtension;
+
+import java.util.Arrays;
+import java.util.Random;
+
+import org.junit.Test;
+
+public class PerMessageDeflateDecoderTest {
+
+    private static final Random random = new Random();
+
+    @Test
+    public void testCompressedFrame() {
+        EmbeddedChannel encoderChannel = new EmbeddedChannel(
+                ZlibCodecFactory.newZlibEncoder(ZlibWrapper.NONE, 9, 15, 8));
+        EmbeddedChannel decoderChannel = new EmbeddedChannel(new PerMessageDeflateDecoder(false));
+
+        // initialize
+        byte[] payload = new byte[300];
+        random.nextBytes(payload);
+
+        encoderChannel.writeOutbound(Unpooled.wrappedBuffer(payload));
+        ByteBuf compressedPayload = encoderChannel.readOutbound();
+
+        BinaryWebSocketFrame compressedFrame = new BinaryWebSocketFrame(true,
+                WebSocketExtension.RSV1 | WebSocketExtension.RSV3,
+                compressedPayload.slice(0, compressedPayload.readableBytes() - 4));
+
+        // execute
+        decoderChannel.writeInbound(compressedFrame);
+        BinaryWebSocketFrame uncompressedFrame = decoderChannel.readInbound();
+
+        // test
+        assertNotNull(uncompressedFrame);
+        assertNotNull(uncompressedFrame.content());
+        assertTrue(uncompressedFrame instanceof BinaryWebSocketFrame);
+        assertEquals(WebSocketExtension.RSV3, uncompressedFrame.rsv());
+        assertEquals(300, uncompressedFrame.content().readableBytes());
+
+        byte[] finalPayload = new byte[300];
+        uncompressedFrame.content().readBytes(finalPayload);
+        assertTrue(Arrays.equals(finalPayload, payload));
+        uncompressedFrame.release();
+    }
+
+    @Test
+    public void testNormalFrame() {
+        EmbeddedChannel decoderChannel = new EmbeddedChannel(new PerMessageDeflateDecoder(false));
+
+        // initialize
+        byte[] payload = new byte[300];
+        random.nextBytes(payload);
+
+        BinaryWebSocketFrame frame = new BinaryWebSocketFrame(true,
+                WebSocketExtension.RSV3, Unpooled.wrappedBuffer(payload));
+
+        // execute
+        decoderChannel.writeInbound(frame);
+        BinaryWebSocketFrame newFrame = decoderChannel.readInbound();
+
+        // test
+        assertNotNull(newFrame);
+        assertNotNull(newFrame.content());
+        assertTrue(newFrame instanceof BinaryWebSocketFrame);
+        assertEquals(WebSocketExtension.RSV3, newFrame.rsv());
+        assertEquals(300, newFrame.content().readableBytes());
+
+        byte[] finalPayload = new byte[300];
+        newFrame.content().readBytes(finalPayload);
+        assertTrue(Arrays.equals(finalPayload, payload));
+        newFrame.release();
+    }
+
+    @Test
+    public void testFramementedFrame() {
+        EmbeddedChannel encoderChannel = new EmbeddedChannel(
+                ZlibCodecFactory.newZlibEncoder(ZlibWrapper.NONE, 9, 15, 8));
+        EmbeddedChannel decoderChannel = new EmbeddedChannel(new PerMessageDeflateDecoder(false));
+
+        // initialize
+        byte[] payload = new byte[300];
+        random.nextBytes(payload);
+
+        encoderChannel.writeOutbound(Unpooled.wrappedBuffer(payload));
+        ByteBuf compressedPayload = encoderChannel.readOutbound();
+        compressedPayload = compressedPayload.slice(0, compressedPayload.readableBytes() - 4);
+
+        int oneThird = compressedPayload.readableBytes() / 3;
+        BinaryWebSocketFrame compressedFrame1 = new BinaryWebSocketFrame(false,
+                WebSocketExtension.RSV1 | WebSocketExtension.RSV3,
+                compressedPayload.slice(0, oneThird));
+        ContinuationWebSocketFrame compressedFrame2 = new ContinuationWebSocketFrame(false,
+                WebSocketExtension.RSV3, compressedPayload.slice(oneThird, oneThird));
+        ContinuationWebSocketFrame compressedFrame3 = new ContinuationWebSocketFrame(true,
+                WebSocketExtension.RSV3, compressedPayload.slice(oneThird * 2,
+                        compressedPayload.readableBytes() - oneThird * 2));
+
+        // execute
+        decoderChannel.writeInbound(compressedFrame1.retain());
+        decoderChannel.writeInbound(compressedFrame2.retain());
+        decoderChannel.writeInbound(compressedFrame3);
+        BinaryWebSocketFrame uncompressedFrame1 = decoderChannel.readInbound();
+        ContinuationWebSocketFrame uncompressedFrame2 = decoderChannel.readInbound();
+        ContinuationWebSocketFrame uncompressedFrame3 = decoderChannel.readInbound();
+
+        // test
+        assertNotNull(uncompressedFrame1);
+        assertNotNull(uncompressedFrame2);
+        assertNotNull(uncompressedFrame3);
+        assertEquals(WebSocketExtension.RSV3, uncompressedFrame1.rsv());
+        assertEquals(WebSocketExtension.RSV3, uncompressedFrame2.rsv());
+        assertEquals(WebSocketExtension.RSV3, uncompressedFrame3.rsv());
+
+        ByteBuf finalPayloadWrapped = Unpooled.wrappedBuffer(uncompressedFrame1.content(),
+                uncompressedFrame2.content(), uncompressedFrame3.content());
+        assertEquals(300, finalPayloadWrapped.readableBytes());
+
+        byte[] finalPayload = new byte[300];
+        finalPayloadWrapped.readBytes(finalPayload);
+        assertTrue(Arrays.equals(finalPayload, payload));
+        uncompressedFrame1.release();
+        uncompressedFrame2.release();
+        uncompressedFrame3.release();
+    }
+
+    @Test
+    public void testMultiCompressedPayloadWithinFrame() {
+        EmbeddedChannel encoderChannel = new EmbeddedChannel(
+                ZlibCodecFactory.newZlibEncoder(ZlibWrapper.NONE, 9, 15, 8));
+        EmbeddedChannel decoderChannel = new EmbeddedChannel(new PerMessageDeflateDecoder(false));
+
+        // initialize
+        byte[] payload1 = new byte[100];
+        random.nextBytes(payload1);
+        byte[] payload2 = new byte[100];
+        random.nextBytes(payload2);
+
+        encoderChannel.writeOutbound(Unpooled.wrappedBuffer(payload1));
+        ByteBuf compressedPayload1 = encoderChannel.readOutbound();
+        encoderChannel.writeOutbound(Unpooled.wrappedBuffer(payload2));
+        ByteBuf compressedPayload2 = encoderChannel.readOutbound();
+
+        BinaryWebSocketFrame compressedFrame = new BinaryWebSocketFrame(true,
+                WebSocketExtension.RSV1 | WebSocketExtension.RSV3,
+                Unpooled.wrappedBuffer(
+                        compressedPayload1,
+                        compressedPayload2.slice(0, compressedPayload2.readableBytes() - 4)));
+
+        // execute
+        decoderChannel.writeInbound(compressedFrame);
+        BinaryWebSocketFrame uncompressedFrame = decoderChannel.readInbound();
+
+        // test
+        assertNotNull(uncompressedFrame);
+        assertNotNull(uncompressedFrame.content());
+        assertTrue(uncompressedFrame instanceof BinaryWebSocketFrame);
+        assertEquals(WebSocketExtension.RSV3, uncompressedFrame.rsv());
+        assertEquals(200, uncompressedFrame.content().readableBytes());
+
+        byte[] finalPayload1 = new byte[100];
+        uncompressedFrame.content().readBytes(finalPayload1);
+        assertTrue(Arrays.equals(finalPayload1, payload1));
+        byte[] finalPayload2 = new byte[100];
+        uncompressedFrame.content().readBytes(finalPayload2);
+        assertTrue(Arrays.equals(finalPayload2, payload2));
+        uncompressedFrame.release();
+    }
+
+}

codec-http/src/test/java/io/netty/handler/codec/http/websocketx/extensions/compression/PerMessageDeflateEncoderTest.java

@@ -0,0 +1,160 @@
+/*
+ * Copyright 2014 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.extensions.compression;
+
+import static org.junit.Assert.*;
+import io.netty.buffer.ByteBuf;
+import io.netty.buffer.Unpooled;
+import io.netty.channel.embedded.EmbeddedChannel;
+import io.netty.handler.codec.compression.ZlibCodecFactory;
+import io.netty.handler.codec.compression.ZlibWrapper;
+import io.netty.handler.codec.http.websocketx.BinaryWebSocketFrame;
+import io.netty.handler.codec.http.websocketx.ContinuationWebSocketFrame;
+import io.netty.handler.codec.http.websocketx.extensions.WebSocketExtension;
+
+import java.util.Arrays;
+import java.util.Random;
+
+import org.junit.Test;
+
+public class PerMessageDeflateEncoderTest {
+
+    private static final Random random = new Random();
+
+    @Test
+    public void testCompressedFrame() {
+        EmbeddedChannel encoderChannel = new EmbeddedChannel(new PerMessageDeflateEncoder(9, 15, false));
+        EmbeddedChannel decoderChannel = new EmbeddedChannel(
+                ZlibCodecFactory.newZlibDecoder(ZlibWrapper.NONE));
+
+        // initialize
+        byte[] payload = new byte[300];
+        random.nextBytes(payload);
+        BinaryWebSocketFrame frame = new BinaryWebSocketFrame(true,
+                WebSocketExtension.RSV3, Unpooled.wrappedBuffer(payload));
+
+        // execute
+        encoderChannel.writeOutbound(frame);
+        BinaryWebSocketFrame compressedFrame = encoderChannel.readOutbound();
+
+        // test
+        assertNotNull(compressedFrame);
+        assertNotNull(compressedFrame.content());
+        assertTrue(compressedFrame instanceof BinaryWebSocketFrame);
+        assertEquals(WebSocketExtension.RSV1 | WebSocketExtension.RSV3, compressedFrame.rsv());
+
+        decoderChannel.writeInbound(compressedFrame.content());
+        decoderChannel.writeInbound(DeflateDecoder.FRAME_TAIL);
+        ByteBuf uncompressedPayload = decoderChannel.readInbound();
+        assertEquals(300, uncompressedPayload.readableBytes());
+
+        byte[] finalPayload = new byte[300];
+        uncompressedPayload.readBytes(finalPayload);
+        assertTrue(Arrays.equals(finalPayload, payload));
+        uncompressedPayload.release();
+    }
+
+    @Test
+    public void testAlreadyCompressedFrame() {
+        EmbeddedChannel encoderChannel = new EmbeddedChannel(new PerMessageDeflateEncoder(9, 15, false));
+
+        // initialize
+        byte[] payload = new byte[300];
+        random.nextBytes(payload);
+
+        BinaryWebSocketFrame frame = new BinaryWebSocketFrame(true,
+                WebSocketExtension.RSV3 | WebSocketExtension.RSV1, Unpooled.wrappedBuffer(payload));
+
+        // execute
+        encoderChannel.writeOutbound(frame);
+        BinaryWebSocketFrame newFrame = encoderChannel.readOutbound();
+
+        // test
+        assertNotNull(newFrame);
+        assertNotNull(newFrame.content());
+        assertTrue(newFrame instanceof BinaryWebSocketFrame);
+        assertEquals(WebSocketExtension.RSV3 | WebSocketExtension.RSV1, newFrame.rsv());
+        assertEquals(300, newFrame.content().readableBytes());
+
+        byte[] finalPayload = new byte[300];
+        newFrame.content().readBytes(finalPayload);
+        assertTrue(Arrays.equals(finalPayload, payload));
+        newFrame.release();
+    }
+
+    @Test
+    public void testFramementedFrame() {
+        EmbeddedChannel encoderChannel = new EmbeddedChannel(new PerMessageDeflateEncoder(9, 15, false));
+        EmbeddedChannel decoderChannel = new EmbeddedChannel(
+                ZlibCodecFactory.newZlibDecoder(ZlibWrapper.NONE));
+
+        // initialize
+        byte[] payload1 = new byte[100];
+        random.nextBytes(payload1);
+        byte[] payload2 = new byte[100];
+        random.nextBytes(payload2);
+        byte[] payload3 = new byte[100];
+        random.nextBytes(payload3);
+
+        BinaryWebSocketFrame frame1 = new BinaryWebSocketFrame(false,
+                WebSocketExtension.RSV3, Unpooled.wrappedBuffer(payload1));
+        ContinuationWebSocketFrame frame2 = new ContinuationWebSocketFrame(false,
+                WebSocketExtension.RSV3, Unpooled.wrappedBuffer(payload2));
+        ContinuationWebSocketFrame frame3 = new ContinuationWebSocketFrame(true,
+                WebSocketExtension.RSV3, Unpooled.wrappedBuffer(payload3));
+
+        // execute
+        encoderChannel.writeOutbound(frame1);
+        encoderChannel.writeOutbound(frame2);
+        encoderChannel.writeOutbound(frame3);
+        BinaryWebSocketFrame compressedFrame1 = encoderChannel.readOutbound();
+        ContinuationWebSocketFrame compressedFrame2 = encoderChannel.readOutbound();
+        ContinuationWebSocketFrame compressedFrame3 = encoderChannel.readOutbound();
+
+        // test
+        assertNotNull(compressedFrame1);
+        assertNotNull(compressedFrame2);
+        assertNotNull(compressedFrame3);
+        assertEquals(WebSocketExtension.RSV1 | WebSocketExtension.RSV3, compressedFrame1.rsv());
+        assertEquals(WebSocketExtension.RSV3, compressedFrame2.rsv());
+        assertEquals(WebSocketExtension.RSV3, compressedFrame3.rsv());
+        assertFalse(compressedFrame1.isFinalFragment());
+        assertFalse(compressedFrame2.isFinalFragment());
+        assertTrue(compressedFrame3.isFinalFragment());
+
+        decoderChannel.writeInbound(compressedFrame1.content());
+        ByteBuf uncompressedPayload1 = decoderChannel.readInbound();
+        byte[] finalPayload1 = new byte[100];
+        uncompressedPayload1.readBytes(finalPayload1);
+        assertTrue(Arrays.equals(finalPayload1, payload1));
+        uncompressedPayload1.release();
+
+        decoderChannel.writeInbound(compressedFrame2.content());
+        ByteBuf uncompressedPayload2 = decoderChannel.readInbound();
+        byte[] finalPayload2 = new byte[100];
+        uncompressedPayload2.readBytes(finalPayload2);
+        assertTrue(Arrays.equals(finalPayload2, payload2));
+        uncompressedPayload2.release();
+
+        decoderChannel.writeInbound(compressedFrame3.content());
+        decoderChannel.writeInbound(DeflateDecoder.FRAME_TAIL);
+        ByteBuf uncompressedPayload3 = decoderChannel.readInbound();
+        byte[] finalPayload3 = new byte[100];
+        uncompressedPayload3.readBytes(finalPayload3);
+        assertTrue(Arrays.equals(finalPayload3, payload3));
+        uncompressedPayload3.release();
+    }
+}

codec-http/src/test/java/io/netty/handler/codec/http/websocketx/extensions/compression/PerMessageDeflateServerExtensionHandshakerTest.java

@@ -0,0 +1,172 @@
+/*
+ * Copyright 2014 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.extensions.compression;
+
+import static io.netty.handler.codec.http.websocketx.extensions.compression.
+        PerMessageDeflateServerExtensionHandshaker.*;
+import static org.junit.Assert.*;
+import io.netty.handler.codec.http.websocketx.extensions.WebSocketServerExtension;
+import io.netty.handler.codec.http.websocketx.extensions.WebSocketExtensionData;
+
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.Map;
+
+import org.junit.Test;
+
+public class PerMessageDeflateServerExtensionHandshakerTest {
+
+    @Test
+    public void testNormalHandshake() {
+        WebSocketServerExtension extension;
+        WebSocketExtensionData data;
+        Map<String, String> parameters;
+
+        // initialize
+        PerMessageDeflateServerExtensionHandshaker handshaker =
+                new PerMessageDeflateServerExtensionHandshaker();
+
+        // execute
+        extension = handshaker.handshakeExtension(
+                new WebSocketExtensionData(PERMESSAGE_DEFLATE_EXTENSION, Collections.<String, String>emptyMap()));
+
+        // test
+        assertNotNull(extension);
+        assertEquals(WebSocketServerExtension.RSV1, extension.rsv());
+        assertTrue(extension.newExtensionDecoder() instanceof PerMessageDeflateDecoder);
+        assertTrue(extension.newExtensionEncoder() instanceof PerMessageDeflateEncoder);
+
+        // execute
+        data = extension.newReponseData();
+
+        assertEquals(PERMESSAGE_DEFLATE_EXTENSION, data.name());
+        assertTrue(data.parameters().isEmpty());
+
+        // initialize
+        parameters = new HashMap<String, String>();
+        parameters.put(CLIENT_MAX_WINDOW, null);
+        parameters.put(CLIENT_NO_CONTEXT, null);
+
+        // execute
+        extension = handshaker.handshakeExtension(
+                new WebSocketExtensionData(PERMESSAGE_DEFLATE_EXTENSION, Collections.<String, String>emptyMap()));
+
+        // test
+        assertNotNull(extension);
+        assertEquals(WebSocketServerExtension.RSV1, extension.rsv());
+        assertTrue(extension.newExtensionDecoder() instanceof PerMessageDeflateDecoder);
+        assertTrue(extension.newExtensionEncoder() instanceof PerMessageDeflateEncoder);
+
+        // execute
+        data = extension.newReponseData();
+
+        // test
+        assertEquals(PERMESSAGE_DEFLATE_EXTENSION, data.name());
+        assertTrue(data.parameters().isEmpty());
+
+        // initialize
+        parameters = new HashMap<String, String>();
+        parameters.put(SERVER_MAX_WINDOW, "12");
+        parameters.put(SERVER_NO_CONTEXT, null);
+
+        // execute
+        extension = handshaker.handshakeExtension(
+                new WebSocketExtensionData(PERMESSAGE_DEFLATE_EXTENSION, parameters));
+
+        // test
+        assertNull(extension);
+    }
+
+    @Test
+    public void testCustomHandshake() {
+        WebSocketServerExtension extension;
+        Map<String, String> parameters;
+        WebSocketExtensionData data;
+
+        // initialize
+        PerMessageDeflateServerExtensionHandshaker handshaker =
+                new PerMessageDeflateServerExtensionHandshaker(6, true, 10, true, true);
+
+        parameters = new HashMap<String, String>();
+        parameters.put(CLIENT_MAX_WINDOW, null);
+        parameters.put(SERVER_MAX_WINDOW, "12");
+        parameters.put(CLIENT_NO_CONTEXT, null);
+        parameters.put(SERVER_NO_CONTEXT, null);
+
+        // execute
+        extension = handshaker.handshakeExtension(
+                new WebSocketExtensionData(PERMESSAGE_DEFLATE_EXTENSION, parameters));
+
+        // test
+        assertNotNull(extension);
+        assertEquals(WebSocketServerExtension.RSV1, extension.rsv());
+        assertTrue(extension.newExtensionDecoder() instanceof PerMessageDeflateDecoder);
+        assertTrue(extension.newExtensionEncoder() instanceof PerMessageDeflateEncoder);
+
+        // execute
+        data = extension.newReponseData();
+
+        // test
+        assertEquals(PERMESSAGE_DEFLATE_EXTENSION, data.name());
+        assertTrue(data.parameters().containsKey(CLIENT_MAX_WINDOW));
+        assertTrue(data.parameters().get(CLIENT_MAX_WINDOW).equals("10"));
+        assertTrue(data.parameters().containsKey(SERVER_MAX_WINDOW));
+        assertTrue(data.parameters().get(SERVER_MAX_WINDOW).equals("12"));
+        assertTrue(data.parameters().containsKey(CLIENT_MAX_WINDOW));
+        assertTrue(data.parameters().containsKey(SERVER_MAX_WINDOW));
+
+        // initialize
+        parameters = new HashMap<String, String>();
+        parameters.put(SERVER_MAX_WINDOW, "12");
+        parameters.put(SERVER_NO_CONTEXT, null);
+
+        // execute
+        extension = handshaker.handshakeExtension(
+                new WebSocketExtensionData(PERMESSAGE_DEFLATE_EXTENSION, parameters));
+
+        // test
+        assertNotNull(extension);
+        assertEquals(WebSocketServerExtension.RSV1, extension.rsv());
+        assertTrue(extension.newExtensionDecoder() instanceof PerMessageDeflateDecoder);
+        assertTrue(extension.newExtensionEncoder() instanceof PerMessageDeflateEncoder);
+
+        // execute
+        data = extension.newReponseData();
+
+        // test
+        assertEquals(PERMESSAGE_DEFLATE_EXTENSION, data.name());
+        assertEquals(2, data.parameters().size());
+        assertTrue(data.parameters().containsKey(SERVER_MAX_WINDOW));
+        assertTrue(data.parameters().get(SERVER_MAX_WINDOW).equals("12"));
+        assertTrue(data.parameters().containsKey(SERVER_NO_CONTEXT));
+
+        // initialize
+        parameters = new HashMap<String, String>();
+
+        // execute
+        extension = handshaker.handshakeExtension(
+                new WebSocketExtensionData(PERMESSAGE_DEFLATE_EXTENSION, parameters));
+        // test
+        assertNotNull(extension);
+
+        // execute
+        data = extension.newReponseData();
+
+        // test
+        assertEquals(PERMESSAGE_DEFLATE_EXTENSION, data.name());
+        assertTrue(data.parameters().isEmpty());
+    }
+}

codec-http/src/test/java/io/netty/handler/codec/http/websocketx/extensions/compression/WebSocketServerCompressionHandlerTest.java

@@ -0,0 +1,196 @@
+/*
+ * Copyright 2014 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.extensions.compression;
+
+import static io.netty.handler.codec.http.websocketx.extensions.compression.
+        PerMessageDeflateServerExtensionHandshaker.*;
+import static io.netty.handler.codec.http.websocketx.extensions.WebSocketExtensionTestUtil.*;
+import io.netty.channel.embedded.EmbeddedChannel;
+import io.netty.handler.codec.http.HttpRequest;
+import io.netty.handler.codec.http.HttpResponse;
+import io.netty.handler.codec.http.websocketx.extensions.WebSocketExtensionData;
+import io.netty.handler.codec.http.websocketx.extensions.WebSocketExtensionUtil;
+import io.netty.handler.codec.http.websocketx.extensions.WebSocketServerExtensionHandler;
+import io.netty.handler.codec.http.HttpHeaders.Names;
+
+import java.util.List;
+
+import org.junit.Assert;
+import org.junit.Test;
+
+public class WebSocketServerCompressionHandlerTest {
+
+    @Test
+    public void testNormalSuccess() {
+        EmbeddedChannel ch = new EmbeddedChannel(new WebSocketServerCompressionHandler());
+
+        HttpRequest req = newUpgradeRequest(PERMESSAGE_DEFLATE_EXTENSION);
+        ch.writeInbound(req);
+
+        HttpResponse res = newUpgradeResponse(null);
+        ch.writeOutbound(res);
+
+        HttpResponse res2 = ch.readOutbound();
+        List<WebSocketExtensionData> exts = WebSocketExtensionUtil.extractExtensions(
+                res2.headers().get(Names.SEC_WEBSOCKET_EXTENSIONS));
+
+        Assert.assertEquals(PERMESSAGE_DEFLATE_EXTENSION, exts.get(0).name());
+        Assert.assertTrue(exts.get(0).parameters().isEmpty());
+        Assert.assertTrue(ch.pipeline().get(PerMessageDeflateDecoder.class) != null);
+        Assert.assertTrue(ch.pipeline().get(PerMessageDeflateEncoder.class) != null);
+    }
+
+    @Test
+    public void testClientWindowSizeSuccess() {
+        EmbeddedChannel ch = new EmbeddedChannel(new WebSocketServerExtensionHandler(
+                new PerMessageDeflateServerExtensionHandshaker(6, false, 10, false, false)));
+
+        HttpRequest req = newUpgradeRequest(PERMESSAGE_DEFLATE_EXTENSION + "; " + CLIENT_MAX_WINDOW);
+        ch.writeInbound(req);
+
+        HttpResponse res = newUpgradeResponse(null);
+        ch.writeOutbound(res);
+
+        HttpResponse res2 = ch.readOutbound();
+        List<WebSocketExtensionData> exts = WebSocketExtensionUtil.extractExtensions(
+                res2.headers().get(Names.SEC_WEBSOCKET_EXTENSIONS));
+
+        Assert.assertEquals(PERMESSAGE_DEFLATE_EXTENSION, exts.get(0).name());
+        Assert.assertEquals("10", exts.get(0).parameters().get(CLIENT_MAX_WINDOW));
+        Assert.assertTrue(ch.pipeline().get(PerMessageDeflateDecoder.class) != null);
+        Assert.assertTrue(ch.pipeline().get(PerMessageDeflateEncoder.class) != null);
+    }
+
+    @Test
+    public void testClientWindowSizeUnavailable() {
+        EmbeddedChannel ch = new EmbeddedChannel(new WebSocketServerExtensionHandler(
+                new PerMessageDeflateServerExtensionHandshaker(6, false, 10, false, false)));
+
+        HttpRequest req = newUpgradeRequest(PERMESSAGE_DEFLATE_EXTENSION);
+        ch.writeInbound(req);
+
+        HttpResponse res = newUpgradeResponse(null);
+        ch.writeOutbound(res);
+
+        HttpResponse res2 = ch.readOutbound();
+        List<WebSocketExtensionData> exts = WebSocketExtensionUtil.extractExtensions(
+                res2.headers().get(Names.SEC_WEBSOCKET_EXTENSIONS));
+
+        Assert.assertEquals(PERMESSAGE_DEFLATE_EXTENSION, exts.get(0).name());
+        Assert.assertTrue(exts.get(0).parameters().isEmpty());
+        Assert.assertTrue(ch.pipeline().get(PerMessageDeflateDecoder.class) != null);
+        Assert.assertTrue(ch.pipeline().get(PerMessageDeflateEncoder.class) != null);
+    }
+
+    @Test
+    public void testServerWindowSizeSuccess() {
+        EmbeddedChannel ch = new EmbeddedChannel(new WebSocketServerExtensionHandler(
+                new PerMessageDeflateServerExtensionHandshaker(6, true, 15, false, false)));
+
+        HttpRequest req = newUpgradeRequest(PERMESSAGE_DEFLATE_EXTENSION + "; " + SERVER_MAX_WINDOW + "=10");
+        ch.writeInbound(req);
+
+        HttpResponse res = newUpgradeResponse(null);
+        ch.writeOutbound(res);
+
+        HttpResponse res2 = ch.readOutbound();
+        List<WebSocketExtensionData> exts = WebSocketExtensionUtil.extractExtensions(
+                res2.headers().get(Names.SEC_WEBSOCKET_EXTENSIONS));
+
+        Assert.assertEquals(PERMESSAGE_DEFLATE_EXTENSION, exts.get(0).name());
+        Assert.assertEquals("10", exts.get(0).parameters().get(SERVER_MAX_WINDOW));
+        Assert.assertTrue(ch.pipeline().get(PerMessageDeflateDecoder.class) != null);
+        Assert.assertTrue(ch.pipeline().get(PerMessageDeflateEncoder.class) != null);
+    }
+
+    @Test
+    public void testServerWindowSizeDisable() {
+        EmbeddedChannel ch = new EmbeddedChannel(new WebSocketServerExtensionHandler(
+                new PerMessageDeflateServerExtensionHandshaker(6, false, 15, false, false)));
+
+        HttpRequest req = newUpgradeRequest(PERMESSAGE_DEFLATE_EXTENSION + "; " + SERVER_MAX_WINDOW + "=10");
+        ch.writeInbound(req);
+
+        HttpResponse res = newUpgradeResponse(null);
+        ch.writeOutbound(res);
+
+        HttpResponse res2 = ch.readOutbound();
+
+        Assert.assertFalse(res2.headers().contains(Names.SEC_WEBSOCKET_EXTENSIONS));
+        Assert.assertTrue(ch.pipeline().get(PerMessageDeflateDecoder.class) == null);
+        Assert.assertTrue(ch.pipeline().get(PerMessageDeflateEncoder.class) == null);
+    }
+
+    @Test
+    public void testServerNoContext() {
+        EmbeddedChannel ch = new EmbeddedChannel(new WebSocketServerCompressionHandler());
+
+        HttpRequest req = newUpgradeRequest(PERMESSAGE_DEFLATE_EXTENSION + "; " + SERVER_NO_CONTEXT);
+        ch.writeInbound(req);
+
+        HttpResponse res = newUpgradeResponse(null);
+        ch.writeOutbound(res);
+
+        HttpResponse res2 = ch.readOutbound();
+
+        Assert.assertFalse(res2.headers().contains(Names.SEC_WEBSOCKET_EXTENSIONS));
+        Assert.assertTrue(ch.pipeline().get(PerMessageDeflateDecoder.class) == null);
+        Assert.assertTrue(ch.pipeline().get(PerMessageDeflateEncoder.class) == null);
+    }
+
+    @Test
+    public void testClientNoContext() {
+        EmbeddedChannel ch = new EmbeddedChannel(new WebSocketServerCompressionHandler());
+
+        HttpRequest req = newUpgradeRequest(PERMESSAGE_DEFLATE_EXTENSION + "; " + CLIENT_NO_CONTEXT);
+        ch.writeInbound(req);
+
+        HttpResponse res = newUpgradeResponse(null);
+        ch.writeOutbound(res);
+
+        HttpResponse res2 = ch.readOutbound();
+        List<WebSocketExtensionData> exts = WebSocketExtensionUtil.extractExtensions(
+                res2.headers().get(Names.SEC_WEBSOCKET_EXTENSIONS));
+
+        Assert.assertEquals(PERMESSAGE_DEFLATE_EXTENSION, exts.get(0).name());
+        Assert.assertTrue(exts.get(0).parameters().isEmpty());
+        Assert.assertTrue(ch.pipeline().get(PerMessageDeflateDecoder.class) != null);
+        Assert.assertTrue(ch.pipeline().get(PerMessageDeflateEncoder.class) != null);
+    }
+
+    @Test
+    public void testServerWindowSizeDisableThenFallback() {
+        EmbeddedChannel ch = new EmbeddedChannel(new WebSocketServerExtensionHandler(
+                new PerMessageDeflateServerExtensionHandshaker(6, false, 15, false, false)));
+
+        HttpRequest req = newUpgradeRequest(PERMESSAGE_DEFLATE_EXTENSION + "; " + SERVER_MAX_WINDOW + "=10, " +
+                PERMESSAGE_DEFLATE_EXTENSION);
+        ch.writeInbound(req);
+
+        HttpResponse res = newUpgradeResponse(null);
+        ch.writeOutbound(res);
+
+        HttpResponse res2 = ch.readOutbound();
+        List<WebSocketExtensionData> exts = WebSocketExtensionUtil.extractExtensions(
+                res2.headers().get(Names.SEC_WEBSOCKET_EXTENSIONS));
+
+        Assert.assertEquals(PERMESSAGE_DEFLATE_EXTENSION, exts.get(0).name());
+        Assert.assertTrue(exts.get(0).parameters().isEmpty());
+        Assert.assertTrue(ch.pipeline().get(PerMessageDeflateDecoder.class) != null);
+        Assert.assertTrue(ch.pipeline().get(PerMessageDeflateEncoder.class) != null);
+    }
+
+}

codec/src/main/java/io/netty/handler/codec/compression/ZlibCodecFactory.java

@@ -66,7 +66,7 @@ public final class ZlibCodecFactory {
 
     public static ZlibEncoder newZlibEncoder(ZlibWrapper wrapper, int compressionLevel, int windowBits, int memLevel) {
         if (PlatformDependent.javaVersion() < 7 || noJdkZlibEncoder ||
-            windowBits != DEFAULT_JDK_WINDOW_SIZE || memLevel != DEFAULT_JDK_MEM_LEVEL) {
+                windowBits != DEFAULT_JDK_WINDOW_SIZE || memLevel != DEFAULT_JDK_MEM_LEVEL) {
             return new JZlibEncoder(wrapper, compressionLevel, windowBits, memLevel);
         } else {
             return new JdkZlibEncoder(wrapper, compressionLevel);
@@ -91,7 +91,7 @@ public final class ZlibCodecFactory {
 
     public static ZlibEncoder newZlibEncoder(int compressionLevel, int windowBits, int memLevel, byte[] dictionary) {
         if (PlatformDependent.javaVersion() < 7 || noJdkZlibEncoder ||
-            windowBits != DEFAULT_JDK_WINDOW_SIZE || memLevel != DEFAULT_JDK_MEM_LEVEL) {
+                windowBits != DEFAULT_JDK_WINDOW_SIZE || memLevel != DEFAULT_JDK_MEM_LEVEL) {
             return new JZlibEncoder(compressionLevel, windowBits, memLevel, dictionary);
         } else {
             return new JdkZlibEncoder(compressionLevel, dictionary);

example/src/main/java/io/netty/example/http/websocketx/client/WebSocketClient.java

@@ -33,6 +33,7 @@ import io.netty.handler.codec.http.websocketx.TextWebSocketFrame;
 import io.netty.handler.codec.http.websocketx.WebSocketClientHandshakerFactory;
 import io.netty.handler.codec.http.websocketx.WebSocketFrame;
 import io.netty.handler.codec.http.websocketx.WebSocketVersion;
+import io.netty.handler.codec.http.websocketx.extensions.compression.WebSocketClientCompressionHandler;
 import io.netty.handler.ssl.SslContext;
 import io.netty.handler.ssl.SslContextBuilder;
 import io.netty.handler.ssl.util.InsecureTrustManagerFactory;
@@ -113,6 +114,7 @@ public final class WebSocketClient {
                      p.addLast(
                              new HttpClientCodec(),
                              new HttpObjectAggregator(8192),
+                             new WebSocketClientCompressionHandler(),
                              handler);
                  }
              });

example/src/main/java/io/netty/example/http/websocketx/server/WebSocketServerInitializer.java

@@ -20,6 +20,7 @@ import io.netty.channel.ChannelPipeline;
 import io.netty.channel.socket.SocketChannel;
 import io.netty.handler.codec.http.HttpObjectAggregator;
 import io.netty.handler.codec.http.HttpServerCodec;
+import io.netty.handler.codec.http.websocketx.extensions.compression.WebSocketServerCompressionHandler;
 import io.netty.handler.ssl.SslContext;
 
 /**
@@ -40,6 +41,7 @@ public class WebSocketServerInitializer extends ChannelInitializer<SocketChannel
         }
         pipeline.addLast(new HttpServerCodec());
         pipeline.addLast(new HttpObjectAggregator(65536));
+        pipeline.addLast(new WebSocketServerCompressionHandler());
         pipeline.addLast(new WebSocketServerHandler());
     }
 }