Merge pull request #2496 from nmittler/http2

Adding a general handler for upgrading protocols

codec-http/src/main/java/io/netty/handler/codec/http/HttpClientCodec.java

@@ -40,7 +40,8 @@ import java.util.concurrent.atomic.AtomicLong;
  *
  * @see HttpServerCodec
  */
-public final class HttpClientCodec extends ChannelHandlerAppender {
+public final class HttpClientCodec extends ChannelHandlerAppender implements
+        HttpClientUpgradeHandler.SourceCodec {
 
     /** A queue that is used for correlating a request and a response. */
     private final Queue<HttpMethod> queue = new ArrayDeque<HttpMethod>();
@@ -86,6 +87,16 @@ public final class HttpClientCodec extends ChannelHandlerAppender {
         this.failOnMissingResponse = failOnMissingResponse;
     }
 
+    /**
+     * Upgrades to another protocol from HTTP. Removes the {@link Decoder} and {@link Encoder} from
+     * the pipeline.
+     */
+    @Override
+    public void upgradeFrom(ChannelHandlerContext ctx) {
+        ctx.pipeline().remove(Decoder.class);
+        ctx.pipeline().remove(Encoder.class);
+    }
+
     private Decoder decoder() {
         return handlerAt(0);
     }

codec-http/src/main/java/io/netty/handler/codec/http/HttpClientUpgradeHandler.java

@@ -0,0 +1,234 @@
+/*
+ * 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;
+
+import static io.netty.handler.codec.http.HttpHeaders.Names.CONNECTION;
+import static io.netty.handler.codec.http.HttpHeaders.Names.UPGRADE;
+import static io.netty.handler.codec.http.HttpResponseStatus.SWITCHING_PROTOCOLS;
+import static io.netty.util.ReferenceCountUtil.release;
+import io.netty.channel.ChannelHandlerContext;
+import io.netty.channel.ChannelPromise;
+
+import java.util.Collection;
+import java.util.LinkedHashSet;
+import java.util.List;
+import java.util.Set;
+
+/**
+ * Client-side handler for handling an HTTP upgrade handshake to another protocol. When the first
+ * HTTP request is sent, this handler will add all appropriate headers to perform an upgrade to the
+ * new protocol. If the upgrade fails (i.e. response is not 101 Switching Protocols), this handler
+ * simply removes itself from the pipeline. If the upgrade is successful, upgrades the pipeline to
+ * the new protocol.
+ */
+public class HttpClientUpgradeHandler extends HttpObjectAggregator {
+
+    /**
+     * User events that are fired to notify about upgrade status.
+     */
+    public enum UpgradeEvent {
+        /**
+         * The Upgrade request was sent to the server.
+         */
+        UPGRADE_ISSUED,
+
+        /**
+         * The Upgrade to the new protocol was successful.
+         */
+        UPGRADE_SUCCESSFUL,
+
+        /**
+         * The Upgrade was unsuccessful due to the server not issuing
+         * with a 101 Switching Protocols response.
+         */
+        UPGRADE_REJECTED
+    }
+
+    /**
+     * The source codec that is used in the pipeline initially.
+     */
+    public interface SourceCodec {
+        /**
+         * Removes this codec (i.e. all associated handlers) from the pipeline.
+         */
+        void upgradeFrom(ChannelHandlerContext ctx);
+    }
+
+    /**
+     * A codec that the source can be upgraded to.
+     */
+    public interface UpgradeCodec {
+        /**
+         * Returns the name of the protocol supported by this codec, as indicated by the {@link UPGRADE} header.
+         */
+        String protocol();
+
+        /**
+         * Sets any protocol-specific headers required to the upgrade request. Returns the names of
+         * all headers that were added. These headers will be used to populate the CONNECTION header.
+         */
+        Collection<String> setUpgradeHeaders(ChannelHandlerContext ctx, HttpRequest upgradeRequest);
+
+        /**
+         * Performs an HTTP protocol upgrade from the source codec. This method is responsible for
+         * adding all handlers required for the new protocol.
+         *
+         * @param ctx the context for the current handler.
+         * @param upgradeResponse the 101 Switching Protocols response that indicates that the server
+         *            has switched to this protocol.
+         */
+        void upgradeTo(ChannelHandlerContext ctx, FullHttpResponse upgradeResponse) throws Exception;
+    }
+
+    private final SourceCodec sourceCodec;
+    private final UpgradeCodec upgradeCodec;
+    private boolean upgradeRequested;
+
+    /**
+     * Constructs the client upgrade handler.
+     *
+     * @param sourceCodec the codec that is being used initially.
+     * @param upgradeCodec the codec that the client would like to upgrade to.
+     * @param maxContentLength the maximum length of the aggregated content.
+     */
+    public HttpClientUpgradeHandler(SourceCodec sourceCodec, UpgradeCodec upgradeCodec,
+            int maxContentLength) {
+        super(maxContentLength);
+        if (sourceCodec == null) {
+            throw new NullPointerException("sourceCodec");
+        }
+        if (upgradeCodec == null) {
+            throw new NullPointerException("upgradeCodec");
+        }
+        this.sourceCodec = sourceCodec;
+        this.upgradeCodec = upgradeCodec;
+    }
+
+    @Override
+    public void write(ChannelHandlerContext ctx, Object msg, ChannelPromise promise)
+            throws Exception {
+        if (!(msg instanceof HttpRequest)) {
+            super.write(ctx, msg, promise);
+            return;
+        }
+
+        if (upgradeRequested) {
+            promise.setFailure(new IllegalStateException(
+                    "Attempting to write HTTP request with upgrade in progress"));
+            return;
+        }
+
+        upgradeRequested = true;
+        setUpgradeRequestHeaders(ctx, (HttpRequest) msg);
+
+        // Continue writing the request.
+        super.write(ctx, msg, promise);
+
+        // Notify that the upgrade request was issued.
+        ctx.fireUserEventTriggered(UpgradeEvent.UPGRADE_ISSUED);
+        // Now we wait for the next HTTP response to see if we switch protocols.
+    }
+
+    @Override
+    protected void decode(ChannelHandlerContext ctx, HttpObject msg, List<Object> out)
+            throws Exception {
+        FullHttpResponse response = null;
+        try {
+            if (!upgradeRequested) {
+                throw new IllegalStateException("Read HTTP response without requesting protocol switch");
+            }
+
+            if (msg instanceof FullHttpResponse) {
+                response = (FullHttpResponse) msg;
+                // Need to retain since the base class will release after returning from this method.
+                response.retain();
+                out.add(response);
+            } else {
+                // Call the base class to handle the aggregation of the full request.
+                super.decode(ctx, msg, out);
+                if (out.isEmpty()) {
+                    // The full request hasn't been created yet, still awaiting more data.
+                    return;
+                }
+
+                assert out.size() == 1;
+                response = (FullHttpResponse) out.get(0);
+            }
+
+            if (!SWITCHING_PROTOCOLS.equals(response.getStatus())) {
+                // The server does not support the requested protocol, just remove this handler
+                // and continue processing HTTP.
+                // NOTE: not releasing the response since we're letting it propagate to the
+                // next handler.
+                ctx.fireUserEventTriggered(UpgradeEvent.UPGRADE_REJECTED);
+                removeThisHandler(ctx);
+                return;
+            }
+
+            String upgradeHeader = response.headers().get(UPGRADE);
+            if (upgradeHeader == null) {
+                throw new IllegalStateException(
+                        "Switching Protocols response missing UPGRADE header");
+            }
+            if (!upgradeCodec.protocol().equalsIgnoreCase(upgradeHeader)) {
+                throw new IllegalStateException(
+                        "Switching Protocols response with unexpected UPGRADE protocol: "
+                                + upgradeHeader);
+            }
+
+            // Upgrade to the new protocol.
+            sourceCodec.upgradeFrom(ctx);
+            upgradeCodec.upgradeTo(ctx, response);
+
+            // Notify that the upgrade to the new protocol completed successfully.
+            ctx.fireUserEventTriggered(UpgradeEvent.UPGRADE_SUCCESSFUL);
+
+            // We switched protocols, so we're done with the upgrade response.
+            // Release it and clear it from the output.
+            response.release();
+            out.clear();
+            removeThisHandler(ctx);
+        } catch (Throwable t) {
+            release(response);
+            ctx.fireExceptionCaught(t);
+            removeThisHandler(ctx);
+        }
+    }
+
+    private void removeThisHandler(ChannelHandlerContext ctx) {
+        ctx.pipeline().remove(ctx.name());
+    }
+
+    /**
+     * Adds all upgrade request headers necessary for an upgrade to the supported protocols.
+     */
+    private void setUpgradeRequestHeaders(ChannelHandlerContext ctx, HttpRequest request) {
+        // Set the UPGRADE header on the request.
+        request.headers().set(UPGRADE, upgradeCodec.protocol());
+
+        // Add all protocol-specific headers to the request.
+        Set<String> connectionParts = new LinkedHashSet<String>(2);
+        connectionParts.addAll(upgradeCodec.setUpgradeHeaders(ctx, request));
+
+        // Set the CONNECTION header from the set of all protocol-specific headers that were added.
+        StringBuilder builder = new StringBuilder();
+        for (String part : connectionParts) {
+            builder.append(part);
+            builder.append(",");
+        }
+        builder.append(UPGRADE);
+        request.headers().set(CONNECTION, builder.toString());
+    }
+}

codec-http/src/main/java/io/netty/handler/codec/http/HttpServerCodec.java

@@ -16,15 +16,20 @@
 package io.netty.handler.codec.http;
 
 import io.netty.channel.ChannelHandlerAppender;
+import io.netty.channel.ChannelHandlerContext;
 
 
 /**
  * A combination of {@link HttpRequestDecoder} and {@link HttpResponseEncoder}
- * which enables easier server side HTTP implementation.
+ * which enables easier server side HTTP implementation. Also supports use with
+ * a {@link HttpServerUpgradeHandler} to support upgrading to another protocol
+ * from HTTP.
  *
  * @see HttpClientCodec
+ * @see HttpServerUpgradeHandler
  */
-public final class HttpServerCodec extends ChannelHandlerAppender {
+public final class HttpServerCodec extends ChannelHandlerAppender implements
+        HttpServerUpgradeHandler.SourceCodec {
 
     /**
      * Creates a new instance with the default decoder options
@@ -49,4 +54,14 @@ public final class HttpServerCodec extends ChannelHandlerAppender {
         super(new HttpRequestDecoder(maxInitialLineLength, maxHeaderSize, maxChunkSize, validateHeaders),
                 new HttpResponseEncoder());
     }
+
+    /**
+     * Upgrades to another protocol from HTTP. Removes the {@link HttpRequestDecoder} and
+     * {@link HttpResponseEncoder} from the pipeline.
+     */
+    @Override
+    public void upgradeFrom(ChannelHandlerContext ctx) {
+        ctx.pipeline().remove(HttpRequestDecoder.class);
+        ctx.pipeline().remove(HttpResponseEncoder.class);
+    }
 }

codec-http/src/main/java/io/netty/handler/codec/http/HttpServerUpgradeHandler.java

@@ -0,0 +1,376 @@
+/*
+ * 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;
+
+import static io.netty.handler.codec.http.HttpHeaders.Names.CONNECTION;
+import static io.netty.handler.codec.http.HttpHeaders.Names.CONTENT_LENGTH;
+import static io.netty.handler.codec.http.HttpHeaders.Names.UPGRADE;
+import static io.netty.handler.codec.http.HttpResponseStatus.SWITCHING_PROTOCOLS;
+import static io.netty.handler.codec.http.HttpVersion.HTTP_1_1;
+import static java.lang.String.CASE_INSENSITIVE_ORDER;
+import io.netty.channel.ChannelFuture;
+import io.netty.channel.ChannelFutureListener;
+import io.netty.channel.ChannelHandlerContext;
+import io.netty.util.ReferenceCountUtil;
+import io.netty.util.ReferenceCounted;
+
+import java.util.Collection;
+import java.util.LinkedHashMap;
+import java.util.LinkedHashSet;
+import java.util.List;
+import java.util.Locale;
+import java.util.Map;
+import java.util.Set;
+import java.util.TreeSet;
+
+/**
+ * A server-side handler that receives HTTP requests and optionally performs a protocol switch if
+ * the requested protocol is supported. Once an upgrade is performed, this handler removes itself
+ * from the pipeline.
+ */
+public class HttpServerUpgradeHandler extends HttpObjectAggregator {
+
+    /**
+     * The source codec that is used in the pipeline initially.
+     */
+    public interface SourceCodec {
+        /**
+         * Removes this codec (i.e. all associated handlers) from the pipeline.
+         */
+        void upgradeFrom(ChannelHandlerContext ctx);
+    }
+
+    /**
+     * A codec that the source can be upgraded to.
+     */
+    public interface UpgradeCodec {
+        /**
+         * Returns the name of the protocol supported by this codec, as indicated by the {@link UPGRADE} header.
+         */
+        String protocol();
+
+        /**
+         * Gets all protocol-specific headers required by this protocol for a successful upgrade.
+         * Any supplied header will be required to appear in the {@link CONNECTION} header as well.
+         */
+        Collection<String> requiredUpgradeHeaders();
+
+        /**
+         * Adds any headers to the 101 Switching protocols response that are appropriate for this protocol.
+         */
+        void prepareUpgradeResponse(ChannelHandlerContext ctx, FullHttpRequest upgradeRequest,
+                FullHttpResponse upgradeResponse);
+
+        /**
+         * Performs an HTTP protocol upgrade from the source codec. This method is responsible for
+         * adding all handlers required for the new protocol.
+         *
+         * @param ctx the context for the current handler.
+         * @param upgradeRequest the request that triggered the upgrade to this protocol. The
+         *            upgraded protocol is responsible for sending the response.
+         * @param upgradeResponse a 101 Switching Protocols response that is populated with the
+         *            {@link CONNECTION} and {@link UPGRADE} headers. The protocol is required to
+         *            send this before sending any other frames back to the client. The headers may
+         *            be augmented as necessary by the protocol before sending.
+         * @return the future for the writing of the upgrade response.
+         */
+        void upgradeTo(ChannelHandlerContext ctx, FullHttpRequest upgradeRequest,
+                FullHttpResponse upgradeResponse);
+    }
+
+    /**
+     * User event that is fired to notify about the completion of an HTTP upgrade
+     * to another protocol. Contains the original upgrade request so that the response
+     * (if required) can be sent using the new protocol.
+     */
+    public static final class UpgradeEvent implements ReferenceCounted {
+        private final String protocol;
+        private final FullHttpRequest upgradeRequest;
+
+        private UpgradeEvent(String protocol, FullHttpRequest upgradeRequest) {
+            this.protocol = protocol;
+            this.upgradeRequest = upgradeRequest;
+        }
+
+        /**
+         * The protocol that the channel has been upgraded to.
+         */
+        public String protocol() {
+            return protocol;
+        }
+
+        /**
+         * Gets the request that triggered the protocol upgrade.
+         */
+        public FullHttpRequest upgradeRequest() {
+            return upgradeRequest;
+        }
+
+        @Override
+        public int refCnt() {
+            return upgradeRequest.refCnt();
+        }
+
+        @Override
+        public UpgradeEvent retain() {
+            upgradeRequest.retain();
+            return this;
+        }
+
+        @Override
+        public UpgradeEvent retain(int increment) {
+            upgradeRequest.retain(increment);
+            return this;
+        }
+
+        @Override
+        public UpgradeEvent touch() {
+            upgradeRequest.touch();
+            return this;
+        }
+
+        @Override
+        public UpgradeEvent touch(Object hint) {
+            upgradeRequest.touch(hint);
+            return this;
+        }
+
+        @Override
+        public boolean release() {
+            return upgradeRequest.release();
+        }
+
+        @Override
+        public boolean release(int decrement) {
+            return upgradeRequest.release();
+        }
+
+        @Override
+        public String toString() {
+            return "UpgradeEvent [protocol=" + protocol + ", upgradeRequest=" + upgradeRequest
+                    + "]";
+        }
+    }
+
+    private final Map<String, UpgradeCodec> upgradeCodecMap;
+    private final SourceCodec sourceCodec;
+    private boolean handlingUpgrade;
+
+    /**
+     * Constructs the upgrader with the supported codecs.
+     *
+     * @param sourceCodec the codec that is being used initially.
+     * @param upgradeCodecs the codecs (in order of preference) that this server supports
+     *            upgrading to from the source codec.
+     * @param maxContentLength the maximum length of the aggregated content.
+     */
+    public HttpServerUpgradeHandler(SourceCodec sourceCodec,
+            Collection<UpgradeCodec> upgradeCodecs, int maxContentLength) {
+        super(maxContentLength);
+        if (sourceCodec == null) {
+            throw new NullPointerException("sourceCodec");
+        }
+        if (upgradeCodecs == null) {
+            throw new NullPointerException("upgradeCodecs");
+        }
+        this.sourceCodec = sourceCodec;
+        upgradeCodecMap = new LinkedHashMap<String, UpgradeCodec>(upgradeCodecs.size());
+        for (UpgradeCodec upgradeCodec : upgradeCodecs) {
+            String name = upgradeCodec.protocol().toUpperCase(Locale.US);
+            upgradeCodecMap.put(name, upgradeCodec);
+        }
+    }
+
+    @Override
+    protected void decode(ChannelHandlerContext ctx, HttpObject msg, List<Object> out)
+            throws Exception {
+        // Determine if we're already handling an upgrade request or just starting a new one.
+        handlingUpgrade = handlingUpgrade || isUpgradeRequest(msg);
+        if (!handlingUpgrade) {
+            // Not handling an upgrade request, just pass it to the next handler.
+            ReferenceCountUtil.retain(msg);
+            out.add(msg);
+            return;
+        }
+
+        FullHttpRequest fullRequest = null;
+        if (msg instanceof FullHttpRequest) {
+            fullRequest = (FullHttpRequest) msg;
+            ReferenceCountUtil.retain(msg);
+            out.add(msg);
+        } else {
+            // Call the base class to handle the aggregation of the full request.
+            super.decode(ctx, msg, out);
+            if (out.isEmpty()) {
+                // The full request hasn't been created yet, still awaiting more data.
+                return;
+            }
+
+            // Finished aggregating the full request, get it from the output list.
+            assert out.size() == 1;
+            handlingUpgrade = false;
+            fullRequest = (FullHttpRequest) out.get(0);
+        }
+
+        if (upgrade(ctx, fullRequest)) {
+            // The upgrade was successful, remove the message from the output list
+            // so that it's not propagated to the next handler. This request will
+            // be propagated as a user event instead.
+            out.clear();
+        }
+
+        // The upgrade did not succeed, just allow the full request to propagate to the
+        // next handler.
+    }
+
+    /**
+     * Determines whether or not the message is an HTTP upgrade request.
+     */
+    private boolean isUpgradeRequest(HttpObject msg) {
+        return (msg instanceof HttpRequest) && ((HttpRequest) msg).headers().get(UPGRADE) != null;
+    }
+
+    /**
+     * Attempts to upgrade to the protocol(s) identified by the {@link UPGRADE} header (if provided
+     * in the request).
+     *
+     * @param ctx the context for this handler.
+     * @param request the HTTP request.
+     * @return {@code true} if the upgrade occurred, otherwise {@code false}.
+     */
+    private boolean upgrade(final ChannelHandlerContext ctx, final FullHttpRequest request) {
+        // Select the best protocol based on those requested in the UPGRADE header.
+        String upgradeHeader = request.headers().get(UPGRADE);
+        final UpgradeCodec upgradeCodec = selectUpgradeCodec(upgradeHeader);
+        if (upgradeCodec == null) {
+            // None of the requested protocols are supported, don't upgrade.
+            return false;
+        }
+
+        // Make sure the CONNECTION header is present.
+        String connectionHeader = request.headers().get(CONNECTION);
+        if (connectionHeader == null) {
+            return false;
+        }
+
+        // Make sure the CONNECTION header contains UPGRADE as well as all protocol-specific headers.
+        Collection<String> requiredHeaders = upgradeCodec.requiredUpgradeHeaders();
+        Set<String> values = splitHeader(connectionHeader);
+        if (!values.contains(UPGRADE.toString()) || !values.containsAll(requiredHeaders)) {
+            return false;
+        }
+
+        // Ensure that all required protocol-specific headers are found in the request.
+        for (String requiredHeader : requiredHeaders) {
+            if (!request.headers().contains(requiredHeader)) {
+                return false;
+            }
+        }
+
+        // Create the user event to be fired once the upgrade completes.
+        final UpgradeEvent event = new UpgradeEvent(upgradeCodec.protocol(), request);
+
+        // Prepare and send the upgrade response. Wait for this write to complete before upgrading,
+        // since we need the old codec in-place to properly encode the response.
+        final FullHttpResponse upgradeResponse = createUpgradeResponse(upgradeCodec);
+        upgradeCodec.prepareUpgradeResponse(ctx, request, upgradeResponse);
+        ctx.writeAndFlush(upgradeResponse).addListener(new ChannelFutureListener() {
+            @Override
+            public void operationComplete(ChannelFuture future) throws Exception {
+                try {
+                    if (future.isSuccess()) {
+                        // Perform the upgrade to the new protocol.
+                        sourceCodec.upgradeFrom(ctx);
+                        upgradeCodec.upgradeTo(ctx, request, upgradeResponse);
+
+                        // Notify that the upgrade has occurred. Retain the event to offset
+                        // the release() in the finally block.
+                        ctx.fireUserEventTriggered(event.retain());
+
+                        // Remove this handler from the pipeline.
+                        ctx.pipeline().remove(HttpServerUpgradeHandler.this);
+                    } else {
+                        future.channel().close();
+                    }
+                } finally {
+                    // Release the event if the upgrade event wasn't fired.
+                    event.release();
+                }
+            }
+        });
+        return true;
+    }
+
+    /**
+     * Looks up the most desirable supported upgrade codec from the list of choices in the UPGRADE
+     * header. If no suitable codec was found, returns {@code null}.
+     */
+    private UpgradeCodec selectUpgradeCodec(String upgradeHeader) {
+        Set<String> requestedProtocols = splitHeader(upgradeHeader);
+
+        // Retain only the protocols that are in the protocol map. Maintain the original insertion
+        // order into the protocolMap, so that the first one in the remaining set is the most
+        // desirable protocol for the server.
+        Set<String> supportedProtocols = new LinkedHashSet<String>(upgradeCodecMap.keySet());
+        supportedProtocols.retainAll(requestedProtocols);
+
+        if (!supportedProtocols.isEmpty()) {
+            String protocol = supportedProtocols.iterator().next().toUpperCase(Locale.US);
+            return upgradeCodecMap.get(protocol);
+        }
+        return null;
+    }
+
+    /**
+     * Creates the 101 Switching Protocols response message.
+     */
+    private FullHttpResponse createUpgradeResponse(UpgradeCodec upgradeCodec) {
+        DefaultFullHttpResponse res = new DefaultFullHttpResponse(HTTP_1_1, SWITCHING_PROTOCOLS);
+        res.headers().add(CONNECTION, UPGRADE);
+        res.headers().add(UPGRADE, upgradeCodec.protocol());
+        res.headers().add(CONTENT_LENGTH, "0");
+        return res;
+    }
+
+    /**
+     * Splits a comma-separated header value. The returned set is case-insensitive and contains each
+     * part with whitespace removed.
+     */
+    private static Set<String> splitHeader(String header) {
+        StringBuilder builder = new StringBuilder(header.length());
+        Set<String> protocols = new TreeSet<String>(CASE_INSENSITIVE_ORDER);
+        for (int i = 0; i < header.length(); ++i) {
+            char c = header.charAt(i);
+            if (Character.isWhitespace(c)) {
+                // Don't include any whitespace.
+                continue;
+            }
+            if (c == ',') {
+                // Add the string and reset the builder for the next protocol.
+                protocols.add(builder.toString());
+                builder.setLength(0);
+            } else {
+                builder.append(c);
+            }
+        }
+
+        // Add the last protocol
+        if (builder.length() > 0) {
+            protocols.add(builder.toString());
+        }
+
+        return protocols;
+    }
+}

codec-http2/src/main/java/io/netty/handler/codec/http2/AbstractHttp2ConnectionHandler.java

@@ -15,7 +15,9 @@
 
 package io.netty.handler.codec.http2;
 
+import static io.netty.handler.codec.http2.Http2CodecUtil.CONNECTION_STREAM_ID;
 import static io.netty.handler.codec.http2.Http2CodecUtil.DEFAULT_PRIORITY_WEIGHT;
+import static io.netty.handler.codec.http2.Http2CodecUtil.HTTP_UPGRADE_STREAM_ID;
 import static io.netty.handler.codec.http2.Http2CodecUtil.connectionPrefaceBuf;
 import static io.netty.handler.codec.http2.Http2CodecUtil.toByteBuf;
 import static io.netty.handler.codec.http2.Http2CodecUtil.toHttp2Exception;
@@ -61,14 +63,14 @@ public abstract class AbstractHttp2ConnectionHandler extends ByteToMessageDecode
     private final Http2Connection connection;
     private final Http2InboundFlowController inboundFlow;
     private final Http2OutboundFlowController outboundFlow;
+    // We prefer ArrayDeque to LinkedList because later will produce more GC.
+    // This initial capacity is plenty for SETTINGS traffic.
+    private final ArrayDeque<Http2Settings> outstandingLocalSettingsQueue = new ArrayDeque<Http2Settings>(4);
     private ByteBuf clientPrefaceString;
     private boolean prefaceSent;
     private boolean prefaceReceived;
     private ChannelHandlerContext ctx;
     private ChannelFutureListener closeListener;
-    // We prefer ArrayDeque to LinkedList because later will produce more GC.
-    // This initial capacity is plenty for SETTINGS traffic.
-    private final ArrayDeque<Http2Settings> outstandingLocalSettingsQueue = new ArrayDeque<Http2Settings>(4);
 
     protected AbstractHttp2ConnectionHandler(boolean server) {
         this(server, false);
@@ -111,6 +113,45 @@ public abstract class AbstractHttp2ConnectionHandler extends ByteToMessageDecode
         clientPrefaceString = connection.isServer()? connectionPrefaceBuf() : null;
     }
 
+    /**
+     * Handles the client-side (cleartext) upgrade from HTTP to HTTP/2. Reserves local stream 1 for
+     * the HTTP/2 response.
+     */
+    public final void onHttpClientUpgrade() throws Http2Exception {
+        if (connection.isServer()) {
+            throw protocolError("Client-side HTTP upgrade requested for a server");
+        }
+        if (prefaceSent || prefaceReceived) {
+            throw protocolError("HTTP upgrade must occur before HTTP/2 preface is sent or received");
+        }
+
+        // Create a local stream used for the HTTP cleartext upgrade.
+        createLocalStream(HTTP_UPGRADE_STREAM_ID, true, CONNECTION_STREAM_ID,
+                DEFAULT_PRIORITY_WEIGHT, false);
+    }
+
+    /**
+     * Handles the server-side (cleartext) upgrade from HTTP to HTTP/2.
+     *
+     * @param settings the settings for the remote endpoint.
+     */
+    public final void onHttpServerUpgrade(Http2Settings settings)
+            throws Http2Exception {
+        if (!connection.isServer()) {
+            throw protocolError("Server-side HTTP upgrade requested for a client");
+        }
+        if (prefaceSent || prefaceReceived) {
+            throw protocolError("HTTP upgrade must occur before HTTP/2 preface is sent or received");
+        }
+
+        // Apply the settings but no ACK is necessary.
+        applyRemoteSettings(settings);
+
+        // Create a stream in the half-closed state.
+        createRemoteStream(HTTP_UPGRADE_STREAM_ID, true, CONNECTION_STREAM_ID,
+                DEFAULT_PRIORITY_WEIGHT, false);
+    }
+
     @Override
     public void channelActive(ChannelHandlerContext ctx) throws Exception {
         // The channel just became active - send the connection preface to the remote
@@ -186,6 +227,13 @@ public abstract class AbstractHttp2ConnectionHandler extends ByteToMessageDecode
         return settings;
     }
 
+    /**
+     * Gets the next stream ID that can be created by the local endpoint.
+     */
+    protected int nextStreamId() {
+        return connection.local().nextStreamId();
+    }
+
     protected ChannelFuture writeData(final ChannelHandlerContext ctx,
             final ChannelPromise promise, int streamId, final ByteBuf data, int padding,
             boolean endStream, boolean endSegment, boolean compressed) {
@@ -227,14 +275,8 @@ public abstract class AbstractHttp2ConnectionHandler extends ByteToMessageDecode
 
             Http2Stream stream = connection.stream(streamId);
             if (stream == null) {
-                // Creates a new locally-initiated stream.
+                // Create a new locally-initiated stream.
-                stream = connection.local().createStream(streamId, endStream);
+                stream = createLocalStream(streamId, endStream, streamDependency, weight, exclusive);
-
-                // Allow bi-directional traffic.
-                inboundFlow.addStream(streamId);
-                if (!endStream) {
-                    outboundFlow.addStream(streamId, streamDependency, weight, exclusive);
-                }
             } else {
                 // An existing stream...
                 if (stream.state() == RESERVED_LOCAL) {
@@ -308,10 +350,8 @@ public abstract class AbstractHttp2ConnectionHandler extends ByteToMessageDecode
                 throw protocolError("Sending settings after connection going away.");
             }
 
-            if (settings.hasPushEnabled()) {
+            if (settings.hasPushEnabled() && connection.isServer()) {
-                if (connection.isServer()) {
+                throw protocolError("Server sending SETTINGS frame with ENABLE_PUSH specified");
-                    throw protocolError("Server sending SETTINGS frame with ENABLE_PUSH specified");
-                }
             }
 
             return frameWriter.writeSettings(ctx, promise, settings);
@@ -569,6 +609,88 @@ public abstract class AbstractHttp2ConnectionHandler extends ByteToMessageDecode
                 ChannelFutureListener.CLOSE_ON_FAILURE);
     }
 
+    /**
+     * Applies settings sent from the local endpoint.
+     */
+    private void applyLocalSettings(Http2Settings settings) throws Http2Exception {
+        if (settings.hasPushEnabled()) {
+            if (connection.isServer()) {
+                throw protocolError("Server sending SETTINGS frame with ENABLE_PUSH specified");
+            }
+            connection.local().allowPushTo(settings.pushEnabled());
+        }
+
+        if (settings.hasAllowCompressedData()) {
+            connection.local().allowCompressedData(settings.allowCompressedData());
+        }
+
+        if (settings.hasMaxConcurrentStreams()) {
+            connection.remote().maxStreams(settings.maxConcurrentStreams());
+        }
+
+        if (settings.hasMaxHeaderTableSize()) {
+            frameReader.maxHeaderTableSize(settings.maxHeaderTableSize());
+        }
+
+        if (settings.hasInitialWindowSize()) {
+            inboundFlow.initialInboundWindowSize(settings.initialWindowSize());
+        }
+    }
+
+    /**
+     * Applies settings received from the remote endpoint.
+     */
+    private void applyRemoteSettings(Http2Settings settings) throws Http2Exception {
+        if (settings.hasPushEnabled()) {
+            if (!connection.isServer()) {
+                throw protocolError("Client received SETTINGS frame with ENABLE_PUSH specified");
+            }
+            connection.remote().allowPushTo(settings.pushEnabled());
+        }
+
+        if (settings.hasAllowCompressedData()) {
+            connection.remote().allowCompressedData(settings.allowCompressedData());
+        }
+
+        if (settings.hasMaxConcurrentStreams()) {
+            connection.local().maxStreams(settings.maxConcurrentStreams());
+        }
+
+        if (settings.hasMaxHeaderTableSize()) {
+            frameWriter.maxHeaderTableSize(settings.maxHeaderTableSize());
+        }
+
+        if (settings.hasInitialWindowSize()) {
+            outboundFlow.initialOutboundWindowSize(settings.initialWindowSize());
+        }
+    }
+
+    /**
+     * Creates a new stream initiated by the local endpoint.
+     */
+    private Http2Stream createLocalStream(int streamId, boolean halfClosed, int streamDependency,
+            short weight, boolean exclusive) throws Http2Exception {
+        Http2Stream stream = connection.local().createStream(streamId, halfClosed);
+        inboundFlow.addStream(streamId);
+        if (!halfClosed) {
+            outboundFlow.addStream(streamId, streamDependency, weight, exclusive);
+        }
+        return stream;
+    }
+
+    /**
+     * Creates a new stream initiated by the remote endpoint.
+     */
+    private Http2Stream createRemoteStream(int streamId, boolean halfClosed, int streamDependency,
+            short weight, boolean exclusive) throws Http2Exception {
+        Http2Stream stream = connection.remote().createStream(streamId, halfClosed);
+        outboundFlow.addStream(streamId, streamDependency, weight, exclusive);
+        if (!halfClosed) {
+            inboundFlow.addStream(streamId);
+        }
+        return stream;
+    }
+
     /**
      * Handles all inbound frames from the network.
      */
@@ -630,14 +752,7 @@ public abstract class AbstractHttp2ConnectionHandler extends ByteToMessageDecode
 
             Http2Stream stream = connection.stream(streamId);
             if (stream == null) {
-                // Create the new stream.
+                createRemoteStream(streamId, endStream, streamDependency, weight, exclusive);
-                connection.remote().createStream(streamId, endStream);
-
-                // Allow bi-directional traffic.
-                outboundFlow.addStream(streamId, streamDependency, weight, exclusive);
-                if (!endStream) {
-                    inboundFlow.addStream(streamId);
-                }
             } else {
                 if (stream.state() == RESERVED_REMOTE) {
                     // Received headers for a reserved push stream ... open it for push to the
@@ -717,25 +832,7 @@ public abstract class AbstractHttp2ConnectionHandler extends ByteToMessageDecode
             Http2Settings settings = outstandingLocalSettingsQueue.poll();
 
             if (settings != null) {
-                if (settings.hasPushEnabled()) {
+                applyLocalSettings(settings);
-                    connection.local().allowPushTo(settings.pushEnabled());
-                }
-
-                if (settings.hasAllowCompressedData()) {
-                    connection.local().allowCompressedData(settings.allowCompressedData());
-                }
-
-                if (settings.hasMaxConcurrentStreams()) {
-                    connection.remote().maxStreams(settings.maxConcurrentStreams());
-                }
-
-                if (settings.hasMaxHeaderTableSize()) {
-                    frameReader.maxHeaderTableSize(settings.maxHeaderTableSize());
-                }
-
-                if (settings.hasInitialWindowSize()) {
-                    inboundFlow.initialInboundWindowSize(settings.initialWindowSize());
-                }
             }
 
             AbstractHttp2ConnectionHandler.this.onSettingsAckRead(ctx);
@@ -744,28 +841,7 @@ public abstract class AbstractHttp2ConnectionHandler extends ByteToMessageDecode
         @Override
         public void onSettingsRead(ChannelHandlerContext ctx, Http2Settings settings)
                 throws Http2Exception {
-            if (settings.hasPushEnabled()) {
+            applyRemoteSettings(settings);
-                if (!connection.isServer()) {
-                    throw protocolError("Client received SETTINGS frame with ENABLE_PUSH specified");
-                }
-                connection.remote().allowPushTo(settings.pushEnabled());
-            }
-
-            if (settings.hasAllowCompressedData()) {
-                connection.remote().allowCompressedData(settings.allowCompressedData());
-            }
-
-            if (settings.hasMaxConcurrentStreams()) {
-                connection.local().maxStreams(settings.maxConcurrentStreams());
-            }
-
-            if (settings.hasMaxHeaderTableSize()) {
-                frameWriter.maxHeaderTableSize(settings.maxHeaderTableSize());
-            }
-
-            if (settings.hasInitialWindowSize()) {
-                outboundFlow.initialOutboundWindowSize(settings.initialWindowSize());
-            }
 
             // Acknowledge receipt of the settings.
             frameWriter.writeSettingsAck(ctx, ctx.newPromise());

codec-http2/src/main/java/io/netty/handler/codec/http2/DefaultHttp2Connection.java

@@ -235,6 +235,13 @@ public class DefaultHttp2Connection implements Http2Connection {
             maxStreams = Integer.MAX_VALUE;
         }
 
+        @Override
+        public int nextStreamId() {
+            // For manually created client-side streams, 1 is reserved for HTTP upgrade, so
+            // start at 3.
+            return nextStreamId > 1? nextStreamId : nextStreamId + 2;
+        }
+
         @Override
         public DefaultStream createStream(int streamId, boolean halfClosed) throws Http2Exception {
             checkNewStreamAllowed(streamId);

codec-http2/src/main/java/io/netty/handler/codec/http2/DefaultHttp2FrameWriter.java

@@ -24,12 +24,9 @@ import static io.netty.handler.codec.http2.Http2CodecUtil.MAX_UNSIGNED_SHORT;
 import static io.netty.handler.codec.http2.Http2CodecUtil.MAX_WEIGHT;
 import static io.netty.handler.codec.http2.Http2CodecUtil.MIN_WEIGHT;
 import static io.netty.handler.codec.http2.Http2CodecUtil.PRIORITY_ENTRY_LENGTH;
-import static io.netty.handler.codec.http2.Http2CodecUtil.SETTINGS_COMPRESS_DATA;
+import static io.netty.handler.codec.http2.Http2CodecUtil.calcSettingsPayloadLength;
-import static io.netty.handler.codec.http2.Http2CodecUtil.SETTINGS_ENABLE_PUSH;
+import static io.netty.handler.codec.http2.Http2CodecUtil.writeFrameHeader;
-import static io.netty.handler.codec.http2.Http2CodecUtil.SETTINGS_HEADER_TABLE_SIZE;
+import static io.netty.handler.codec.http2.Http2CodecUtil.writeSettingsPayload;
-import static io.netty.handler.codec.http2.Http2CodecUtil.SETTINGS_INITIAL_WINDOW_SIZE;
-import static io.netty.handler.codec.http2.Http2CodecUtil.SETTINGS_MAX_CONCURRENT_STREAMS;
-import static io.netty.handler.codec.http2.Http2CodecUtil.SETTING_ENTRY_LENGTH;
 import static io.netty.handler.codec.http2.Http2CodecUtil.writeUnsignedInt;
 import static io.netty.handler.codec.http2.Http2CodecUtil.writeUnsignedShort;
 import static io.netty.util.CharsetUtil.UTF_8;
@@ -160,38 +157,10 @@ public class DefaultHttp2FrameWriter implements Http2FrameWriter {
     public ChannelFuture writeSettings(ChannelHandlerContext ctx, ChannelPromise promise,
             Http2Settings settings) {
         try {
-            int numFields = 0;
+            int payloadLength = calcSettingsPayloadLength(settings);
-            numFields += settings.hasAllowCompressedData() ? 1 : 0;
-            numFields += settings.hasMaxHeaderTableSize() ? 1 : 0;
-            numFields += settings.hasInitialWindowSize() ? 1 : 0;
-            numFields += settings.hasMaxConcurrentStreams() ? 1 : 0;
-            numFields += settings.hasPushEnabled() ? 1 : 0;
-
-            int payloadLength = SETTING_ENTRY_LENGTH * numFields;
             ByteBuf frame = ctx.alloc().buffer(FRAME_HEADER_LENGTH + payloadLength);
             writeFrameHeader(frame, payloadLength, Http2FrameType.SETTINGS, Http2Flags.EMPTY, 0);
-
+            writeSettingsPayload(settings, frame);
-            if (settings.hasAllowCompressedData()) {
-                frame.writeByte(SETTINGS_COMPRESS_DATA);
-                writeUnsignedInt(settings.allowCompressedData() ? 1L : 0L, frame);
-            }
-            if (settings.hasMaxHeaderTableSize()) {
-                frame.writeByte(SETTINGS_HEADER_TABLE_SIZE);
-                writeUnsignedInt(settings.maxHeaderTableSize(), frame);
-            }
-            if (settings.hasInitialWindowSize()) {
-                frame.writeByte(SETTINGS_INITIAL_WINDOW_SIZE);
-                writeUnsignedInt(settings.initialWindowSize(), frame);
-            }
-            if (settings.hasMaxConcurrentStreams()) {
-                frame.writeByte(SETTINGS_MAX_CONCURRENT_STREAMS);
-                writeUnsignedInt(settings.maxConcurrentStreams(), frame);
-            }
-            if (settings.hasPushEnabled()) {
-                // Only write the enable push flag from client endpoints.
-                frame.writeByte(SETTINGS_ENABLE_PUSH);
-                writeUnsignedInt(settings.pushEnabled() ? 1L : 0L, frame);
-            }
             return ctx.writeAndFlush(frame, promise);
         } catch (RuntimeException e) {
             return promise.setFailure(e);
@@ -372,15 +341,6 @@ public class DefaultHttp2FrameWriter implements Http2FrameWriter {
         }
     }
 
-    private static void writeFrameHeader(ByteBuf out, int payloadLength, Http2FrameType type,
-            Http2Flags flags, int streamId) {
-        out.ensureWritable(FRAME_HEADER_LENGTH + payloadLength);
-        out.writeShort(payloadLength);
-        out.writeByte(type.typeCode());
-        out.writeByte(flags.value());
-        out.writeInt(streamId);
-    }
-
     private ChannelFuture writeHeadersInternal(ChannelHandlerContext ctx, ChannelPromise promise,
             int streamId, Http2Headers headers, int padding, boolean endStream, boolean endSegment,
             boolean hasPriority, int streamDependency, short weight, boolean exclusive) {

codec-http2/src/main/java/io/netty/handler/codec/http2/Http2ClientUpgradeCodec.java

@@ -0,0 +1,120 @@
+/*
+ * 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.http2;
+
+import static io.netty.handler.codec.base64.Base64Dialect.URL_SAFE;
+import static io.netty.handler.codec.http2.Http2CodecUtil.HTTP_UPGRADE_PROTOCOL_NAME;
+import static io.netty.handler.codec.http2.Http2CodecUtil.HTTP_UPGRADE_SETTINGS_HEADER;
+import static io.netty.handler.codec.http2.Http2CodecUtil.calcSettingsPayloadLength;
+import static io.netty.handler.codec.http2.Http2CodecUtil.writeSettingsPayload;
+import static io.netty.util.CharsetUtil.UTF_8;
+import static io.netty.util.ReferenceCountUtil.release;
+import io.netty.buffer.ByteBuf;
+import io.netty.channel.ChannelHandlerContext;
+import io.netty.handler.codec.base64.Base64;
+import io.netty.handler.codec.http.FullHttpResponse;
+import io.netty.handler.codec.http.HttpClientUpgradeHandler;
+import io.netty.handler.codec.http.HttpRequest;
+
+import java.util.Arrays;
+import java.util.Collection;
+import java.util.Collections;
+import java.util.List;
+
+/**
+ * Client-side cleartext upgrade codec from HTTP to HTTP/2.
+ */
+public class Http2ClientUpgradeCodec implements HttpClientUpgradeHandler.UpgradeCodec {
+
+    private static final List<String> UPGRADE_HEADERS = Collections.unmodifiableList(Arrays
+            .asList(HTTP_UPGRADE_SETTINGS_HEADER));
+    private final String handlerName;
+    private final AbstractHttp2ConnectionHandler connectionHandler;
+
+    /**
+     * Creates the codec using a default name for the connection handler when adding to the
+     * pipeline.
+     *
+     * @param connectionHandler the HTTP/2 connection handler.
+     */
+    public Http2ClientUpgradeCodec(AbstractHttp2ConnectionHandler connectionHandler) {
+        this("http2ConnectionHandler", connectionHandler);
+    }
+
+    /**
+     * Creates the codec providing an upgrade to the given handler for HTTP/2.
+     *
+     * @param handlerName the name of the HTTP/2 connection handler to be used in the pipeline.
+     * @param connectionHandler the HTTP/2 connection handler.
+     */
+    public Http2ClientUpgradeCodec(String handlerName,
+            AbstractHttp2ConnectionHandler connectionHandler) {
+        if (handlerName == null) {
+            throw new NullPointerException("handlerName");
+        }
+        if (connectionHandler == null) {
+            throw new NullPointerException("connectionHandler");
+        }
+        this.handlerName = handlerName;
+        this.connectionHandler = connectionHandler;
+    }
+
+    @Override
+    public String protocol() {
+        return HTTP_UPGRADE_PROTOCOL_NAME;
+    }
+
+    @Override
+    public Collection<String> setUpgradeHeaders(ChannelHandlerContext ctx,
+            HttpRequest upgradeRequest) {
+        String settingsValue = getSettingsHeaderValue(ctx);
+        upgradeRequest.headers().set(HTTP_UPGRADE_SETTINGS_HEADER, settingsValue);
+        return UPGRADE_HEADERS;
+    }
+
+    @Override
+    public void upgradeTo(ChannelHandlerContext ctx, FullHttpResponse upgradeResponse)
+            throws Exception {
+        // Reserve local stream 1 for the response.
+        connectionHandler.onHttpClientUpgrade();
+
+        // Add the handler to the pipeline.
+        ctx.pipeline().addAfter(ctx.name(), handlerName, connectionHandler);
+    }
+
+    /**
+     * Converts the current settings for the handler to the Base64-encoded representation used in
+     * the HTTP2-Settings upgrade header.
+     */
+    private String getSettingsHeaderValue(ChannelHandlerContext ctx) {
+        ByteBuf buf = null;
+        ByteBuf encodedBuf = null;
+        try {
+            // Get the local settings for the handler.
+            Http2Settings settings = connectionHandler.settings();
+
+            // Serialize the payload of the SETTINGS frame.
+            buf = ctx.alloc().buffer(calcSettingsPayloadLength(settings));
+            writeSettingsPayload(settings, buf);
+
+            // Base64 encode the payload and then convert to a string for the header.
+            encodedBuf = Base64.encode(buf, URL_SAFE);
+            return encodedBuf.toString(UTF_8);
+        } finally {
+            release(buf);
+            release(encodedBuf);
+        }
+    }
+}

codec-http2/src/main/java/io/netty/handler/codec/http2/Http2CodecUtil.java

@@ -31,6 +31,10 @@ public final class Http2CodecUtil {
     private static final byte[] EMPTY_PING = new byte[8];
 
     public static final int CONNECTION_STREAM_ID = 0;
+    public static final int HTTP_UPGRADE_STREAM_ID = 1;
+    public static final String HTTP_UPGRADE_SETTINGS_HEADER = "HTTP2-Settings";
+    public static final String HTTP_UPGRADE_PROTOCOL_NAME = "h2c-12";
+
     public static final int MAX_FRAME_PAYLOAD_LENGTH = 16383;
     public static final int PING_FRAME_PAYLOAD_LENGTH = 8;
     public static final short MAX_UNSIGNED_BYTE = 0xFF;
@@ -126,6 +130,61 @@ public final class Http2CodecUtil {
         out.writeByte((int) ((value & 0xFF)));
     }
 
+    /**
+     * Writes an HTTP/2 frame header to the output buffer.
+     */
+    public static void writeFrameHeader(ByteBuf out, int payloadLength, Http2FrameType type,
+            Http2Flags flags, int streamId) {
+        out.ensureWritable(FRAME_HEADER_LENGTH + payloadLength);
+        out.writeShort(payloadLength);
+        out.writeByte(type.typeCode());
+        out.writeByte(flags.value());
+        out.writeInt(streamId);
+    }
+
+    /**
+     * Calculates the HTTP/2 SETTINGS payload length for the serialized representation
+     * of the given settings.
+     */
+    public static int calcSettingsPayloadLength(Http2Settings settings) {
+        int numFields = 0;
+        numFields += settings.hasAllowCompressedData() ? 1 : 0;
+        numFields += settings.hasMaxHeaderTableSize() ? 1 : 0;
+        numFields += settings.hasInitialWindowSize() ? 1 : 0;
+        numFields += settings.hasMaxConcurrentStreams() ? 1 : 0;
+        numFields += settings.hasPushEnabled() ? 1 : 0;
+
+        return SETTING_ENTRY_LENGTH * numFields;
+    }
+
+    /**
+     * Serializes the settings to the output buffer in the format of an HTTP/2 SETTINGS frame
+     * payload.
+     */
+    public static void writeSettingsPayload(Http2Settings settings, ByteBuf out) {
+        if (settings.hasAllowCompressedData()) {
+            out.writeByte(SETTINGS_COMPRESS_DATA);
+            writeUnsignedInt(settings.allowCompressedData() ? 1L : 0L, out);
+        }
+        if (settings.hasMaxHeaderTableSize()) {
+            out.writeByte(SETTINGS_HEADER_TABLE_SIZE);
+            writeUnsignedInt(settings.maxHeaderTableSize(), out);
+        }
+        if (settings.hasInitialWindowSize()) {
+            out.writeByte(SETTINGS_INITIAL_WINDOW_SIZE);
+            writeUnsignedInt(settings.initialWindowSize(), out);
+        }
+        if (settings.hasMaxConcurrentStreams()) {
+            out.writeByte(SETTINGS_MAX_CONCURRENT_STREAMS);
+            writeUnsignedInt(settings.maxConcurrentStreams(), out);
+        }
+        if (settings.hasPushEnabled()) {
+            // Only write the enable push flag from client endpoints.
+            out.writeByte(SETTINGS_ENABLE_PUSH);
+            writeUnsignedInt(settings.pushEnabled() ? 1L : 0L, out);
+        }
+    }
+
     /**
      * Fails the given promise with the cause and then re-throws the cause.
      */

codec-http2/src/main/java/io/netty/handler/codec/http2/Http2Connection.java

@@ -24,6 +24,11 @@ public interface Http2Connection {
      */
     interface Endpoint {
 
+        /**
+         * Returns the next valid streamId for this endpoint.
+         */
+        int nextStreamId();
+
         /**
          * Creates a stream initiated by this endpoint. This could fail for the following reasons:
          * <p/>

codec-http2/src/main/java/io/netty/handler/codec/http2/Http2FrameAdapter.java

@@ -0,0 +1,91 @@
+/*
+ * 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.http2;
+
+import io.netty.buffer.ByteBuf;
+import io.netty.channel.ChannelHandlerContext;
+
+/**
+ * Convenience class that provides no-op implementations for all methods of {@link Http2FrameObserver}.
+ */
+public class Http2FrameAdapter implements Http2FrameObserver {
+
+    @Override
+    public void onDataRead(ChannelHandlerContext ctx, int streamId, ByteBuf data, int padding,
+            boolean endOfStream, boolean endOfSegment, boolean compressed) throws Http2Exception {
+    }
+
+    @Override
+    public void onHeadersRead(ChannelHandlerContext ctx, int streamId, Http2Headers headers,
+            int padding, boolean endStream, boolean endSegment) throws Http2Exception {
+    }
+
+    @Override
+    public void onHeadersRead(ChannelHandlerContext ctx, int streamId, Http2Headers headers,
+            int streamDependency, short weight, boolean exclusive, int padding, boolean endStream,
+            boolean endSegment) throws Http2Exception {
+    }
+
+    @Override
+    public void onPriorityRead(ChannelHandlerContext ctx, int streamId, int streamDependency,
+            short weight, boolean exclusive) throws Http2Exception {
+    }
+
+    @Override
+    public void onRstStreamRead(ChannelHandlerContext ctx, int streamId, long errorCode)
+            throws Http2Exception {
+    }
+
+    @Override
+    public void onSettingsAckRead(ChannelHandlerContext ctx) throws Http2Exception {
+    }
+
+    @Override
+    public void onSettingsRead(ChannelHandlerContext ctx, Http2Settings settings)
+            throws Http2Exception {
+    }
+
+    @Override
+    public void onPingRead(ChannelHandlerContext ctx, ByteBuf data) throws Http2Exception {
+    }
+
+    @Override
+    public void onPingAckRead(ChannelHandlerContext ctx, ByteBuf data) throws Http2Exception {
+    }
+
+    @Override
+    public void onPushPromiseRead(ChannelHandlerContext ctx, int streamId, int promisedStreamId,
+            Http2Headers headers, int padding) throws Http2Exception {
+    }
+
+    @Override
+    public void onGoAwayRead(ChannelHandlerContext ctx, int lastStreamId, long errorCode,
+            ByteBuf debugData) throws Http2Exception {
+    }
+
+    @Override
+    public void onWindowUpdateRead(ChannelHandlerContext ctx, int streamId, int windowSizeIncrement)
+                    throws Http2Exception {
+    }
+
+    @Override
+    public void onAltSvcRead(ChannelHandlerContext ctx, int streamId, long maxAge, int port,
+            ByteBuf protocolId, String host, String origin) throws Http2Exception {
+    }
+
+    @Override
+    public void onBlockedRead(ChannelHandlerContext ctx, int streamId) throws Http2Exception {
+    }
+}

codec-http2/src/main/java/io/netty/handler/codec/http2/Http2FrameLogger.java

@@ -58,7 +58,7 @@ public class Http2FrameLogger extends ChannelHandlerAdapter {
 
     public void logHeaders(Direction direction, int streamId, Http2Headers headers, int padding,
             boolean endStream, boolean endSegment) {
-        log(direction, "HEADERS: steramId:%d, headers=%s, padding=%d, endStream=%b, endSegment=%b",
+        log(direction, "HEADERS: streamId:%d, headers=%s, padding=%d, endStream=%b, endSegment=%b",
                 streamId, headers, padding, endStream, endSegment);
     }
 
@@ -66,7 +66,7 @@ public class Http2FrameLogger extends ChannelHandlerAdapter {
             int streamDependency, short weight, boolean exclusive, int padding, boolean endStream,
             boolean endSegment) {
         log(direction,
-                "HEADERS: steramId:%d, headers=%s, streamDependency=%d, weight=%d, exclusive=%b, "
+                "HEADERS: streamId:%d, headers=%s, streamDependency=%d, weight=%d, exclusive=%b, "
                         + "padding=%d, endStream=%b, endSegment=%b", streamId, headers,
                 streamDependency, weight, exclusive, padding, endStream, endSegment);
     }
@@ -109,7 +109,7 @@ public class Http2FrameLogger extends ChannelHandlerAdapter {
     }
 
     public void logWindowsUpdate(Direction direction, int streamId, int windowSizeIncrement) {
-        log(direction, "WINDOW_UPDATE: stream=%d, windowSizeIncrement=%d", streamId,
+        log(direction, "WINDOW_UPDATE: streamId=%d, windowSizeIncrement=%d", streamId,
                 windowSizeIncrement);
     }
 

codec-http2/src/main/java/io/netty/handler/codec/http2/Http2ServerUpgradeCodec.java

@@ -0,0 +1,164 @@
+/*
+ * 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.http2;
+
+import static io.netty.handler.codec.base64.Base64Dialect.URL_SAFE;
+import static io.netty.handler.codec.http.HttpResponseStatus.BAD_REQUEST;
+import static io.netty.handler.codec.http2.Http2CodecUtil.HTTP_UPGRADE_PROTOCOL_NAME;
+import static io.netty.handler.codec.http2.Http2CodecUtil.HTTP_UPGRADE_SETTINGS_HEADER;
+import static io.netty.handler.codec.http2.Http2CodecUtil.writeFrameHeader;
+import static io.netty.handler.codec.http2.Http2Flags.EMPTY;
+import static io.netty.handler.codec.http2.Http2FrameType.SETTINGS;
+import io.netty.buffer.ByteBuf;
+import io.netty.buffer.Unpooled;
+import io.netty.channel.ChannelHandlerContext;
+import io.netty.handler.codec.base64.Base64;
+import io.netty.handler.codec.http.FullHttpRequest;
+import io.netty.handler.codec.http.FullHttpResponse;
+import io.netty.handler.codec.http.HttpServerUpgradeHandler;
+import io.netty.util.CharsetUtil;
+
+import java.util.Arrays;
+import java.util.Collection;
+import java.util.Collections;
+import java.util.List;
+
+/**
+ * Server-side codec for performing a cleartext upgrade from HTTP/1.x to HTTP/2.
+ */
+public class Http2ServerUpgradeCodec implements HttpServerUpgradeHandler.UpgradeCodec {
+
+    private static final List<String> REQUIRED_UPGRADE_HEADERS = Collections
+            .unmodifiableList(Arrays.asList(HTTP_UPGRADE_SETTINGS_HEADER));
+    private final String handlerName;
+    private final AbstractHttp2ConnectionHandler connectionHandler;
+    private final Http2FrameReader frameReader;
+    private Http2Settings settings;
+
+    /**
+     * Creates the codec using a default name for the connection handler when adding to the
+     * pipeline.
+     *
+     * @param connectionHandler the HTTP/2 connection handler.
+     */
+    public Http2ServerUpgradeCodec(AbstractHttp2ConnectionHandler connectionHandler) {
+        this("http2ConnectionHandler", connectionHandler);
+    }
+
+    /**
+     * Creates the codec providing an upgrade to the given handler for HTTP/2.
+     *
+     * @param handlerName the name of the HTTP/2 connection handler to be used in the pipeline.
+     * @param connectionHandler the HTTP/2 connection handler.
+     */
+    public Http2ServerUpgradeCodec(String handlerName,
+            AbstractHttp2ConnectionHandler connectionHandler) {
+        if (handlerName == null) {
+            throw new NullPointerException("handlerName");
+        }
+        if (connectionHandler == null) {
+            throw new NullPointerException("connectionHandler");
+        }
+        this.handlerName = handlerName;
+        this.connectionHandler = connectionHandler;
+        this.frameReader = new DefaultHttp2FrameReader();
+    }
+
+    @Override
+    public String protocol() {
+        return HTTP_UPGRADE_PROTOCOL_NAME;
+    }
+
+    @Override
+    public Collection<String> requiredUpgradeHeaders() {
+        return REQUIRED_UPGRADE_HEADERS;
+    }
+
+    @Override
+    public void prepareUpgradeResponse(ChannelHandlerContext ctx, FullHttpRequest upgradeRequest,
+            FullHttpResponse upgradeResponse) {
+        try {
+            // Decode the HTTP2-Settings header and set the settings on the handler to make
+            // sure everything is fine with the request.
+            String settingsHeader = upgradeRequest.headers().get(HTTP_UPGRADE_SETTINGS_HEADER);
+            settings = decodeSettingsHeader(ctx, settingsHeader);
+            connectionHandler.onHttpServerUpgrade(settings);
+            // Everything looks good, no need to modify the response.
+        } catch (Throwable e) {
+            // Send a failed response back to the client.
+            upgradeResponse.setStatus(BAD_REQUEST);
+            upgradeResponse.headers().clear();
+        }
+    }
+
+    @Override
+    public void upgradeTo(final ChannelHandlerContext ctx, FullHttpRequest upgradeRequest,
+            FullHttpResponse upgradeResponse) {
+        // Add the HTTP/2 connection handler to the pipeline immediately following the current
+        // handler.
+        ctx.pipeline().addAfter(ctx.name(), handlerName, connectionHandler);
+    }
+
+    /**
+     * Decodes the settings header and returns a {@link Http2Settings} object.
+     */
+    private Http2Settings decodeSettingsHeader(ChannelHandlerContext ctx, String settingsHeader)
+            throws Http2Exception {
+        ByteBuf header = Unpooled.wrappedBuffer(settingsHeader.getBytes(CharsetUtil.UTF_8));
+        try {
+            // Decode the SETTINGS payload.
+            ByteBuf payload = Base64.decode(header, URL_SAFE);
+
+            // Create an HTTP/2 frame for the settings.
+            ByteBuf frame = createSettingsFrame(ctx, payload);
+
+            // Decode the SETTINGS frame and return the settings object.
+            return decodeSettings(ctx, frame);
+        } finally {
+            header.release();
+        }
+    }
+
+    /**
+     * Decodes the settings frame and returns the settings.
+     */
+    private Http2Settings decodeSettings(ChannelHandlerContext ctx, ByteBuf frame) throws Http2Exception {
+        try {
+            final Http2Settings decodedSettings = new Http2Settings();
+            frameReader.readFrame(ctx, frame, new Http2FrameAdapter() {
+                @Override
+                public void onSettingsRead(ChannelHandlerContext ctx, Http2Settings settings)
+                        throws Http2Exception {
+                    decodedSettings.copy(settings);
+                }
+            });
+            return decodedSettings;
+        } finally {
+            frame.release();
+        }
+    }
+
+    /**
+     * Creates an HTTP2-Settings header with the given payload. The payload buffer is released.
+     */
+    private static ByteBuf createSettingsFrame(ChannelHandlerContext ctx, ByteBuf payload) {
+        ByteBuf frame =
+                ctx.alloc().buffer(Http2CodecUtil.FRAME_HEADER_LENGTH + payload.readableBytes());
+        writeFrameHeader(frame, payload.readableBytes(), SETTINGS, EMPTY, 0);
+        frame.writeBytes(payload);
+        payload.release();
+        return frame;
+    }
+}

codec-http2/src/main/java/io/netty/handler/codec/http2/Http2Settings.java

@@ -180,6 +180,22 @@ public class Http2Settings {
         return this;
     }
 
+    /**
+     * Overwrites this settings object with the values of the given settings.
+     *
+     * @param source the source that will overwrite the current settings.
+     * @return this object.
+     */
+    public Http2Settings copy(Http2Settings source) {
+        this.enabled = source.enabled;
+        this.allowCompressedData = source.allowCompressedData;
+        this.initialWindowSize = source.initialWindowSize;
+        this.maxConcurrentStreams = source.maxConcurrentStreams;
+        this.maxHeaderTableSize = source.maxHeaderTableSize;
+        this.pushEnabled = source.pushEnabled;
+        return this;
+    }
+
     @Override
     public int hashCode() {
         final int prime = 31;

example/src/main/java/io/netty/example/http2/Http2ExampleUtil.java

@@ -0,0 +1,99 @@
+/*
+ * 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.example.http2;
+
+import java.util.Locale;
+
+/**
+ * Utility methods used by the example client and server.
+ */
+public final class Http2ExampleUtil {
+
+    /**
+     * Response header sent in response to the http->http2 cleartext upgrade request.
+     */
+    public static final String UPGRADE_RESPONSE_HEADER = "Http-To-Http2-Upgrade";
+
+    public static final String STANDARD_HOST = "localhost";
+    public static final int STANDARD_HTTP_PORT = 8080;
+    public static final int STANDARD_HTTPS_PORT = 8443;
+    public static final String PORT_ARG = "-port=";
+    public static final String SSL_ARG = "-ssl=";
+    public static final String HOST_ARG = "-host=";
+
+    /**
+     * The configuration for the example client/server endpoints.
+     */
+    public static final class EndpointConfig {
+        private final boolean ssl;
+        private final String host;
+        private final int port;
+
+        public EndpointConfig(boolean ssl, String host, int port) {
+            this.ssl = ssl;
+            this.host = host;
+            this.port = port;
+        }
+
+        public boolean isSsl() {
+            return ssl;
+        }
+
+        public String host() {
+            return host;
+        }
+
+        public int port() {
+            return port;
+        }
+
+        @Override
+        public String toString() {
+            return "EndpointConfig [ssl=" + ssl + ", host=" + host + ", port=" + port + "]";
+        }
+    }
+
+    /**
+     * Parse the command-line arguments to determine the configuration for the endpoint.
+     */
+    public static EndpointConfig parseEndpointConfig(String[] args) {
+        boolean ssl = false;
+        int port = STANDARD_HTTP_PORT;
+        String host = STANDARD_HOST;
+        boolean portSpecified = false;
+        for (String arg : args) {
+            arg = arg.trim().toLowerCase(Locale.US);
+            if (arg.startsWith(PORT_ARG)) {
+                String value = arg.substring(PORT_ARG.length());
+                port = Integer.parseInt(value);
+                portSpecified = true;
+            } else if (arg.startsWith(SSL_ARG)) {
+                String value = arg.substring(SSL_ARG.length());
+                ssl = Boolean.parseBoolean(value);
+                if (!portSpecified) {
+                    // Use the appropriate default.
+                    port = ssl ? STANDARD_HTTPS_PORT : STANDARD_HTTP_PORT;
+                }
+            } else if (arg.startsWith(HOST_ARG)) {
+                host = arg.substring(HOST_ARG.length());
+            }
+        }
+
+        return new EndpointConfig(ssl, host, port);
+    }
+
+    private Http2ExampleUtil() {
+    }
+}

example/src/main/java/io/netty/example/http2/client/Http2Client.java

@@ -14,54 +14,62 @@
  */
 package io.netty.example.http2.client;
 
+import static io.netty.example.http2.Http2ExampleUtil.parseEndpointConfig;
+import static io.netty.handler.codec.http.HttpHeaders.Names.HOST;
+import static io.netty.handler.codec.http.HttpMethod.GET;
+import static io.netty.handler.codec.http.HttpVersion.HTTP_1_1;
 import io.netty.bootstrap.Bootstrap;
-import io.netty.buffer.ByteBuf;
 import io.netty.channel.Channel;
 import io.netty.channel.ChannelFuture;
 import io.netty.channel.ChannelOption;
 import io.netty.channel.EventLoopGroup;
 import io.netty.channel.nio.NioEventLoopGroup;
 import io.netty.channel.socket.nio.NioSocketChannel;
-import io.netty.handler.codec.http.HttpMethod;
+import io.netty.example.http2.Http2ExampleUtil.EndpointConfig;
-import io.netty.handler.codec.http2.DefaultHttp2Headers;
+import io.netty.handler.codec.http.DefaultFullHttpRequest;
-import io.netty.handler.codec.http2.Http2Exception;
+import io.netty.handler.codec.http.FullHttpRequest;
-import io.netty.handler.codec.http2.Http2Headers;
 import io.netty.handler.codec.http2.Http2OrHttpChooser.SelectedProtocol;
 import io.netty.handler.ssl.SslContext;
 import io.netty.handler.ssl.util.InsecureTrustManagerFactory;
 
-import javax.net.ssl.SSLException;
 import java.net.InetSocketAddress;
-import java.util.concurrent.BlockingQueue;
 
-import static java.util.concurrent.TimeUnit.*;
+import javax.net.ssl.SSLException;
 
 /**
  * An HTTP2 client that allows you to send HTTP2 frames to a server. Inbound and outbound frames are
- * logged.
+ * logged. When run from the command-line, sends a single HEADERS frame to the server and gets back
+ * a "Hello World" response.
+ * <p>
+ * To client accepts command-line arguments for {@code -host=<host/ip>}
+ * <i>(default="localhost")</i>, {@code -port=<port number>} <i>(default: http=8080,
+ * https=8443)</i>, and {@code -ssl=<true/false>} <i>(default=false)</i>.
  */
 public class Http2Client {
 
     private final SslContext sslCtx;
-    private final String host;
+    private final EndpointConfig config;
-    private final int port;
+    private Http2ClientConnectionHandler http2ConnectionHandler;
-    private final Http2ClientConnectionHandler http2ConnectionHandler;
     private Channel channel;
     private EventLoopGroup workerGroup;
 
-    public Http2Client(String host, int port) throws SSLException {
+    public Http2Client(EndpointConfig config) throws SSLException {
-        sslCtx = SslContext.newClientContext(
+        this.config = config;
-                null, InsecureTrustManagerFactory.INSTANCE, null,
+        if (config.isSsl()) {
-                SslContext.newApplicationProtocolSelector(
+            sslCtx = SslContext.newClientContext(
-                        SelectedProtocol.HTTP_2.protocolName(),
+                    null, InsecureTrustManagerFactory.INSTANCE, null,
-                        SelectedProtocol.HTTP_1_1.protocolName()),
+                    SslContext.newApplicationProtocolSelector(
-                0, 0);
+                            SelectedProtocol.HTTP_2.protocolName(),
-
+                            SelectedProtocol.HTTP_1_1.protocolName()),
-        this.host = host;
+                    0, 0);
-        this.port = port;
+        } else {
-        http2ConnectionHandler = new Http2ClientConnectionHandler();
+            sslCtx = null;
+        }
     }
 
+    /**
+     * Starts the client and waits for the HTTP/2 upgrade to occur.
+     */
     public void start() throws Exception {
         if (channel != null) {
             System.out.println("Already running!");
@@ -74,15 +82,40 @@ public class Http2Client {
         b.group(workerGroup);
         b.channel(NioSocketChannel.class);
         b.option(ChannelOption.SO_KEEPALIVE, true);
-        b.remoteAddress(new InetSocketAddress(host, port));
+        b.remoteAddress(new InetSocketAddress(config.host(), config.port()));
-        b.handler(new Http2ClientInitializer(sslCtx, http2ConnectionHandler));
+        Http2ClientInitializer initializer = new Http2ClientInitializer(sslCtx);
+        b.handler(initializer);
 
         // Start the client.
         channel = b.connect().syncUninterruptibly().channel();
+        System.out.println("Connected to [" + config.host() + ':' + config.port() + ']');
+
+        // Wait for the HTTP/2 upgrade to occur.
+        http2ConnectionHandler = initializer.connectionHandler();
         http2ConnectionHandler.awaitInitialization();
-        System.out.println("Connected to [" + host + ':' + port + ']');
     }
 
+    /**
+     * Sends the given request to the server.
+     */
+    public void sendRequest(FullHttpRequest request) throws Exception {
+        ChannelFuture requestFuture = channel.writeAndFlush(request).sync();
+        System.out.println("Back from sending headers...");
+        if (!requestFuture.isSuccess()) {
+            throw new RuntimeException(requestFuture.cause());
+        }
+    }
+
+    /**
+     * Waits for the full response to be received.
+     */
+    public void awaitResponse() throws Exception {
+        http2ConnectionHandler.awaitResponse();
+    }
+
+    /**
+     * Closes the channel and waits for shutdown to complete.
+     */
     public void stop() {
         try {
             // Wait until the connection is closed.
@@ -94,51 +127,29 @@ public class Http2Client {
         }
     }
 
-    public ChannelFuture sendHeaders(int streamId, Http2Headers headers) throws Http2Exception {
-        return http2ConnectionHandler.writeHeaders(streamId, headers, 0, true, true);
-    }
-
-    public ChannelFuture send(int streamId, ByteBuf data, int padding, boolean endStream,
-            boolean endSegment, boolean compressed) throws Http2Exception {
-        return http2ConnectionHandler.writeData(streamId, data, padding, endStream, endSegment,
-                compressed);
-    }
-
-    public Http2Headers headers() {
-        return DefaultHttp2Headers.newBuilder().authority(host).method(HttpMethod.GET.name())
-                .build();
-    }
-
-    public BlockingQueue<ChannelFuture> queue() {
-        return http2ConnectionHandler.queue();
-    }
-
     public static void main(String[] args) throws Exception {
-        int port;
+        EndpointConfig config = parseEndpointConfig(args);
-        if (args.length > 0) {
+        System.out.println(config);
-            port = Integer.parseInt(args[0]);
-        } else {
-            port = 8443;
-        }
-
-        final Http2Client client = new Http2Client("localhost", port);
 
+        final Http2Client client = new Http2Client(config);
         try {
+            // Start the client and wait for the HTTP/2 upgrade to complete.
             client.start();
-            System.out.println("Sending headers...");
+
-            ChannelFuture requestFuture = client.sendHeaders(3, client.headers()).sync();
+            // Create a simple GET request with just headers.
+            FullHttpRequest request = new DefaultFullHttpRequest(HTTP_1_1, GET, "/whatever");
+            request.headers().add(HOST, config.host());
+
+            System.out.println("Sending request...");
+            ChannelFuture requestFuture = client.channel.writeAndFlush(request).sync();
             System.out.println("Back from sending headers...");
             if (!requestFuture.isSuccess()) {
                 requestFuture.cause().printStackTrace();
+                return;
             }
 
             // Waits for the complete response
-            ChannelFuture responseFuture = client.queue().poll(5, SECONDS);
+            client.awaitResponse();
-
-            if (!responseFuture.isSuccess()) {
-                responseFuture.cause().printStackTrace();
-            }
-
             System.out.println("Finished HTTP/2 request");
         } catch (Throwable t) {
             t.printStackTrace();

example/src/main/java/io/netty/example/http2/client/Http2ClientConnectionHandler.java

@@ -14,15 +14,17 @@
  */
 package io.netty.example.http2.client;
 
+import static io.netty.example.http2.Http2ExampleUtil.UPGRADE_RESPONSE_HEADER;
 import static io.netty.util.internal.logging.InternalLogLevel.INFO;
 import io.netty.buffer.ByteBuf;
-import io.netty.channel.ChannelFuture;
 import io.netty.channel.ChannelHandlerContext;
 import io.netty.channel.ChannelPromise;
+import io.netty.handler.codec.http.FullHttpMessage;
 import io.netty.handler.codec.http2.AbstractHttp2ConnectionHandler;
 import io.netty.handler.codec.http2.DefaultHttp2Connection;
 import io.netty.handler.codec.http2.DefaultHttp2FrameReader;
 import io.netty.handler.codec.http2.DefaultHttp2FrameWriter;
+import io.netty.handler.codec.http2.DefaultHttp2Headers;
 import io.netty.handler.codec.http2.DefaultHttp2InboundFlowController;
 import io.netty.handler.codec.http2.DefaultHttp2OutboundFlowController;
 import io.netty.handler.codec.http2.Http2Exception;
@@ -36,8 +38,7 @@ import io.netty.handler.codec.http2.Http2Settings;
 import io.netty.util.CharsetUtil;
 import io.netty.util.internal.logging.InternalLoggerFactory;
 
-import java.util.concurrent.BlockingQueue;
+import java.util.Map;
-import java.util.concurrent.LinkedBlockingQueue;
 import java.util.concurrent.TimeUnit;
 
 /**
@@ -47,36 +48,65 @@ import java.util.concurrent.TimeUnit;
 public class Http2ClientConnectionHandler extends AbstractHttp2ConnectionHandler {
     private static final Http2FrameLogger logger = new Http2FrameLogger(INFO,
             InternalLoggerFactory.getInstance(Http2ClientConnectionHandler.class));
-    private final BlockingQueue<ChannelFuture> queue = new LinkedBlockingQueue<ChannelFuture>();
+    private final ChannelPromise initPromise;
-
+    private final ChannelPromise responsePromise;
     private ByteBuf collectedData;
-    private ChannelPromise initialized;
 
-    public Http2ClientConnectionHandler() {
+    public Http2ClientConnectionHandler(ChannelPromise initPromise, ChannelPromise responsePromise) {
         super(new DefaultHttp2Connection(false, false), frameReader(), frameWriter(),
                 new DefaultHttp2InboundFlowController(), new DefaultHttp2OutboundFlowController());
+        this.initPromise = initPromise;
+        this.responsePromise = responsePromise;
     }
 
-    public void awaitInitialization() throws InterruptedException {
+    /**
-        initialized.await(5, TimeUnit.SECONDS);
+     * Wait for this handler to be added after the upgrade to HTTP/2, and for initial preface
+     * handshake to complete.
+     */
+    public void awaitInitialization() throws Exception {
+        if (!initPromise.awaitUninterruptibly(5, TimeUnit.SECONDS)) {
+            throw new IllegalStateException("Timed out waiting for initialization");
+        }
+        if (!initPromise.isSuccess()) {
+            throw new RuntimeException(initPromise.cause());
+        }
     }
 
+    /**
+     * Wait for this full response to be received and printed out.
+     */
+    public void awaitResponse() throws Exception {
+        if (!responsePromise.awaitUninterruptibly(5, TimeUnit.SECONDS)) {
+            throw new IllegalStateException("Timed out waiting for completion of the response");
+        }
+        if (!responsePromise.isSuccess()) {
+            throw new RuntimeException(initPromise.cause());
+        }
+    }
+
+    /**
+     * Handles conversion of a {@link FullHttpMessage} to HTTP/2 frames.
+     */
     @Override
-    public void handlerAdded(ChannelHandlerContext ctx) throws Exception {
+    public void write(ChannelHandlerContext ctx, Object msg, ChannelPromise promise)
-        super.handlerAdded(ctx);
+            throws Exception {
-        initialized = ctx.newPromise();
+        if (msg instanceof FullHttpMessage) {
-    }
+            FullHttpMessage httpMsg = (FullHttpMessage) msg;
+            boolean hasData = httpMsg.content().isReadable();
 
-    public ChannelFuture writeData(int streamId, ByteBuf data, int padding, boolean endStream,
+            // Convert and write the headers.
-            boolean endSegment, boolean compressed) throws Http2Exception {
+            DefaultHttp2Headers.Builder headers = DefaultHttp2Headers.newBuilder();
-        return super.writeData(ctx(), ctx().newPromise(), streamId, data, padding, endStream,
+            for (Map.Entry<String, String> entry : httpMsg.headers().entries()) {
-                endSegment, compressed);
+                headers.add(entry.getKey(), entry.getValue());
-    }
+            }
-
+            int streamId = nextStreamId();
-    public ChannelFuture writeHeaders(int streamId, Http2Headers headers, int padding,
+            writeHeaders(ctx, promise, streamId, headers.build(), 0, !hasData, false);
-            boolean endStream, boolean endSegment) throws Http2Exception {
+            if (hasData) {
-        return super.writeHeaders(ctx(), ctx().newPromise(), streamId, headers, padding, endStream,
+                writeData(ctx, promise, streamId, httpMsg.content(), 0, true, true, false);
-                endSegment);
+            }
+        } else {
+            super.write(ctx, msg, promise);
+        }
     }
 
     @Override
@@ -107,7 +137,7 @@ public class Http2ClientConnectionHandler extends AbstractHttp2ConnectionHandler
             collectedData.release();
             collectedData = null;
 
-            queue.add(ctx().channel().newSucceededFuture());
+            responsePromise.setSuccess();
         }
     }
 
@@ -120,6 +150,9 @@ public class Http2ClientConnectionHandler extends AbstractHttp2ConnectionHandler
     public void onHeadersRead(ChannelHandlerContext ctx, int streamId, Http2Headers headers,
             int streamDependency, short weight, boolean exclusive, int padding, boolean endStream,
             boolean endSegment) throws Http2Exception {
+        if (headers.contains(UPGRADE_RESPONSE_HEADER)) {
+            System.out.println("Received HTTP/2 response to the HTTP->HTTP/2 upgrade request");
+        }
     }
 
     @Override
@@ -139,8 +172,8 @@ public class Http2ClientConnectionHandler extends AbstractHttp2ConnectionHandler
     @Override
     public void onSettingsRead(ChannelHandlerContext ctx, Http2Settings settings)
             throws Http2Exception {
-        if (!initialized.isDone()) {
+        if (!initPromise.isDone()) {
-            initialized.setSuccess();
+            initPromise.setSuccess();
         }
     }
 
@@ -178,17 +211,13 @@ public class Http2ClientConnectionHandler extends AbstractHttp2ConnectionHandler
 
     @Override
     public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception {
-        queue.add(ctx.channel().newFailedFuture(cause));
+        if (!initPromise.isDone()) {
-        cause.printStackTrace();
+            initPromise.setFailure(cause);
-
-        super.exceptionCaught(ctx, cause);
-        if (!initialized.isDone()) {
-            initialized.setFailure(cause);
         }
-    }
+        if (!responsePromise.isDone()) {
-
+            initPromise.setFailure(cause);
-    public BlockingQueue<ChannelFuture> queue() {
+        }
-        return queue;
+        super.exceptionCaught(ctx, cause);
     }
 
     private static Http2FrameReader frameReader() {

example/src/main/java/io/netty/example/http2/client/Http2ClientInitializer.java

@@ -14,9 +14,16 @@
  */
 package io.netty.example.http2.client;
 
+import io.netty.channel.ChannelHandlerAdapter;
+import io.netty.channel.ChannelHandlerContext;
 import io.netty.channel.ChannelInitializer;
 import io.netty.channel.socket.SocketChannel;
-import io.netty.handler.codec.http2.AbstractHttp2ConnectionHandler;
+import io.netty.handler.codec.http.DefaultFullHttpRequest;
+import io.netty.handler.codec.http.HttpClientCodec;
+import io.netty.handler.codec.http.HttpClientUpgradeHandler;
+import io.netty.handler.codec.http.HttpMethod;
+import io.netty.handler.codec.http.HttpVersion;
+import io.netty.handler.codec.http2.Http2ClientUpgradeCodec;
 import io.netty.handler.ssl.SslContext;
 
 /**
@@ -25,15 +32,72 @@ import io.netty.handler.ssl.SslContext;
 public class Http2ClientInitializer extends ChannelInitializer<SocketChannel> {
 
     private final SslContext sslCtx;
-    private final AbstractHttp2ConnectionHandler connectionHandler;
+    private Http2ClientConnectionHandler connectionHandler;
 
-    public Http2ClientInitializer(SslContext sslCtx, AbstractHttp2ConnectionHandler connectionHandler) {
+    public Http2ClientInitializer(SslContext sslCtx) {
         this.sslCtx = sslCtx;
-        this.connectionHandler = connectionHandler;
     }
 
     @Override
     public void initChannel(SocketChannel ch) throws Exception {
+        connectionHandler = new Http2ClientConnectionHandler(ch.newPromise(), ch.newPromise());
+        if (sslCtx != null) {
+            configureSsl(ch);
+        } else {
+            configureClearText(ch);
+        }
+    }
+
+    public Http2ClientConnectionHandler connectionHandler() {
+        return connectionHandler;
+    }
+
+    /**
+     * Configure the pipeline for TLS NPN negotiation to HTTP/2.
+     */
+    private void configureSsl(SocketChannel ch) {
         ch.pipeline().addLast(sslCtx.newHandler(ch.alloc()), connectionHandler);
     }
+
+    /**
+     * Configure the pipeline for a cleartext upgrade from HTTP to HTTP/2.
+     */
+    private void configureClearText(SocketChannel ch) {
+        HttpClientCodec sourceCodec = new HttpClientCodec();
+        Http2ClientUpgradeCodec upgradeCodec = new Http2ClientUpgradeCodec(connectionHandler);
+        HttpClientUpgradeHandler upgradeHandler = new HttpClientUpgradeHandler(sourceCodec, upgradeCodec, 65536);
+
+        ch.pipeline().addLast(sourceCodec);
+        ch.pipeline().addLast(upgradeHandler);
+        ch.pipeline().addLast(new UpgradeRequestHandler());
+        ch.pipeline().addLast(new UserEventLogger());
+    }
+
+    /**
+     * A handler that triggers the cleartext upgrade to HTTP/2 by sending an initial HTTP request.
+     */
+    private static class UpgradeRequestHandler extends ChannelHandlerAdapter {
+        @Override
+        public void channelActive(ChannelHandlerContext ctx) throws Exception {
+            DefaultFullHttpRequest upgradeRequest =
+                    new DefaultFullHttpRequest(HttpVersion.HTTP_1_1, HttpMethod.GET, "/");
+            ctx.writeAndFlush(upgradeRequest);
+
+            super.channelActive(ctx);
+
+            // Done with this handler, remove it from the pipeline.
+            ctx.pipeline().remove(ctx.name());
+        }
+    }
+
+    /**
+     * Class that logs any User Events triggered on this channel.
+     */
+    private static class UserEventLogger extends ChannelHandlerAdapter {
+        @Override
+        public void userEventTriggered(ChannelHandlerContext ctx, Object evt) throws Exception {
+            System.out.println("User Event Triggered: " + evt);
+            super.userEventTriggered(ctx, evt);
+        }
+    }
 }

example/src/main/java/io/netty/example/http2/server/HelloWorldHttp2Handler.java

@@ -15,26 +15,62 @@
 
 package io.netty.example.http2.server;
 
+import static io.netty.example.http2.Http2ExampleUtil.UPGRADE_RESPONSE_HEADER;
+import static io.netty.util.internal.logging.InternalLogLevel.INFO;
 import io.netty.buffer.ByteBuf;
 import io.netty.channel.ChannelHandlerContext;
+import io.netty.example.http2.client.Http2ClientConnectionHandler;
+import io.netty.handler.codec.http.HttpServerUpgradeHandler;
 import io.netty.handler.codec.http2.AbstractHttp2ConnectionHandler;
+import io.netty.handler.codec.http2.DefaultHttp2Connection;
+import io.netty.handler.codec.http2.DefaultHttp2FrameReader;
+import io.netty.handler.codec.http2.DefaultHttp2FrameWriter;
 import io.netty.handler.codec.http2.DefaultHttp2Headers;
+import io.netty.handler.codec.http2.DefaultHttp2InboundFlowController;
+import io.netty.handler.codec.http2.DefaultHttp2OutboundFlowController;
 import io.netty.handler.codec.http2.Http2Exception;
+import io.netty.handler.codec.http2.Http2FrameLogger;
 import io.netty.handler.codec.http2.Http2Headers;
+import io.netty.handler.codec.http2.Http2InboundFrameLogger;
+import io.netty.handler.codec.http2.Http2OutboundFrameLogger;
 import io.netty.handler.codec.http2.Http2Settings;
 import io.netty.util.CharsetUtil;
+import io.netty.util.internal.logging.InternalLoggerFactory;
 
 /**
  * A simple handler that responds with the message "Hello World!".
  */
 public class HelloWorldHttp2Handler extends AbstractHttp2ConnectionHandler {
 
+    private static final Http2FrameLogger logger = new Http2FrameLogger(INFO,
+            InternalLoggerFactory.getInstance(Http2ClientConnectionHandler.class));
     static final byte[] RESPONSE_BYTES = "Hello World".getBytes(CharsetUtil.UTF_8);
 
     public HelloWorldHttp2Handler() {
-        super(true);
+        super(new DefaultHttp2Connection(true, false), new Http2InboundFrameLogger(
+                new DefaultHttp2FrameReader(), logger), new Http2OutboundFrameLogger(
+                new DefaultHttp2FrameWriter(), logger), new DefaultHttp2InboundFlowController(),
+                new DefaultHttp2OutboundFlowController());
     }
 
+    /**
+     * Handles the cleartext HTTP upgrade event. If an upgrade occurred, sends a simple response via HTTP/2
+     * on stream 1 (the stream specifically reserved for cleartext HTTP upgrade).
+     */
+    @Override
+    public void userEventTriggered(ChannelHandlerContext ctx, Object evt) throws Exception {
+        if (evt instanceof HttpServerUpgradeHandler.UpgradeEvent) {
+            // Write an HTTP/2 response to the upgrade request
+            Http2Headers headers =
+                    DefaultHttp2Headers.newBuilder().set(UPGRADE_RESPONSE_HEADER, "true").build();
+            writeHeaders(ctx, ctx.newPromise(), 1, headers, 0, true, true);
+        }
+        super.userEventTriggered(ctx, evt);
+    }
+
+    /**
+     * If receive a frame with end-of-stream set, send a pre-canned response.
+     */
     @Override
     public void onDataRead(ChannelHandlerContext ctx, int streamId, ByteBuf data, int padding,
             boolean endOfStream, boolean endOfSegment, boolean compressed) throws Http2Exception {
@@ -43,6 +79,9 @@ public class HelloWorldHttp2Handler extends AbstractHttp2ConnectionHandler {
         }
     }
 
+    /**
+     * If receive a frame with end-of-stream set, send a pre-canned response.
+     */
     @Override
     public void onHeadersRead(ChannelHandlerContext ctx, int streamId,
             io.netty.handler.codec.http2.Http2Headers headers, int padding, boolean endStream,
@@ -52,6 +91,9 @@ public class HelloWorldHttp2Handler extends AbstractHttp2ConnectionHandler {
         }
     }
 
+    /**
+     * If receive a frame with end-of-stream set, send a pre-canned response.
+     */
     @Override
     public void onHeadersRead(ChannelHandlerContext ctx, int streamId,
             io.netty.handler.codec.http2.Http2Headers headers, int streamDependency, short weight,
@@ -77,7 +119,8 @@ public class HelloWorldHttp2Handler extends AbstractHttp2ConnectionHandler {
     }
 
     @Override
-    public void onSettingsRead(ChannelHandlerContext ctx, Http2Settings settings) throws Http2Exception {
+    public void onSettingsRead(ChannelHandlerContext ctx, Http2Settings settings)
+            throws Http2Exception {
     }
 
     @Override
@@ -100,7 +143,7 @@ public class HelloWorldHttp2Handler extends AbstractHttp2ConnectionHandler {
 
     @Override
     public void onWindowUpdateRead(ChannelHandlerContext ctx, int streamId, int windowSizeIncrement)
-            throws Http2Exception {
+                    throws Http2Exception {
     }
 
     @Override
@@ -118,6 +161,9 @@ public class HelloWorldHttp2Handler extends AbstractHttp2ConnectionHandler {
         super.exceptionCaught(ctx, cause);
     }
 
+    /**
+     * Sends a "Hello World" DATA frame to the client.
+     */
     private void sendResponse(ChannelHandlerContext ctx, int streamId) throws Http2Exception {
         // Send a frame for the response status
         Http2Headers headers = DefaultHttp2Headers.newBuilder().status("200").build();

example/src/main/java/io/netty/example/http2/server/Http2Server.java

@@ -16,12 +16,14 @@
 
 package io.netty.example.http2.server;
 
+import static io.netty.example.http2.Http2ExampleUtil.parseEndpointConfig;
 import io.netty.bootstrap.ServerBootstrap;
 import io.netty.channel.Channel;
 import io.netty.channel.ChannelOption;
 import io.netty.channel.EventLoopGroup;
 import io.netty.channel.nio.NioEventLoopGroup;
 import io.netty.channel.socket.nio.NioServerSocketChannel;
+import io.netty.example.http2.Http2ExampleUtil.EndpointConfig;
 import io.netty.handler.codec.http2.Http2OrHttpChooser.SelectedProtocol;
 import io.netty.handler.ssl.SslContext;
 import io.netty.handler.ssl.util.SelfSignedCertificate;
@@ -29,18 +31,18 @@ import io.netty.handler.ssl.util.SelfSignedCertificate;
 import java.util.Arrays;
 
 /**
- * A HTTP/2 Server that responds to requests with a Hello World.
+ * A HTTP/2 Server that responds to requests with a Hello World. Once started, you can test the
+ * server with the example client.
  * <p>
- * Once started, you can test the server with the example client.
+ * To server accepts command-line arguments for {@code -port=<port number>} <i>(default: http=8080,
+ * https=8443)</i>, and {@code -ssl=<true/false>} <i>(default=false)</i>.
  */
 public class Http2Server {
 
-    private final SslContext sslCtx;
+    private final EndpointConfig config;
-    private final int port;
 
-    public Http2Server(SslContext sslCtx, int port) {
+    public Http2Server(EndpointConfig config) {
-        this.sslCtx = sslCtx;
+        this.config = config;
-        this.port = port;
     }
 
     public void run() throws Exception {
@@ -50,10 +52,23 @@ public class Http2Server {
         try {
             ServerBootstrap b = new ServerBootstrap();
             b.option(ChannelOption.SO_BACKLOG, 1024);
+
+            // If SSL was selected, configure the SSL context.
+            SslContext sslCtx = null;
+            if (config.isSsl()) {
+                SelfSignedCertificate ssc = new SelfSignedCertificate();
+                sslCtx = SslContext.newServerContext(
+                        ssc.certificate(), ssc.privateKey(), null, null,
+                        Arrays.asList(
+                                SelectedProtocol.HTTP_2.protocolName(),
+                                SelectedProtocol.HTTP_1_1.protocolName()),
+                        0, 0);
+            }
+
             b.group(bossGroup, workerGroup).channel(NioServerSocketChannel.class)
                     .childHandler(new Http2ServerInitializer(sslCtx));
 
-            Channel ch = b.bind(port).sync().channel();
+            Channel ch = b.bind(config.port()).sync().channel();
             ch.closeFuture().sync();
         } finally {
             bossGroup.shutdownGracefully();
@@ -62,24 +77,10 @@ public class Http2Server {
     }
 
     public static void main(String[] args) throws Exception {
-        int port;
+        EndpointConfig config = parseEndpointConfig(args);
-        if (args.length > 0) {
+        System.out.println(config);
-            port = Integer.parseInt(args[0]);
-        } else {
-            port = 8443;
-        }
 
-        System.out.println("HTTP2 server started at port " + port + '.');
+        System.out.println("HTTP2 server started at port " + config.port() + '.');
-
+        new Http2Server(config).run();
-        // Configure SSL context.
-        SelfSignedCertificate ssc = new SelfSignedCertificate();
-        SslContext sslCtx = SslContext.newServerContext(
-                ssc.certificate(), ssc.privateKey(), null, null,
-                Arrays.asList(
-                        SelectedProtocol.HTTP_2.protocolName(),
-                        SelectedProtocol.HTTP_1_1.protocolName()),
-                0, 0);
-
-        new Http2Server(sslCtx, port).run();
     }
 }

example/src/main/java/io/netty/example/http2/server/Http2ServerInitializer.java

@@ -16,15 +16,26 @@
 
 package io.netty.example.http2.server;
 
+import io.netty.channel.ChannelHandlerAdapter;
+import io.netty.channel.ChannelHandlerAppender;
+import io.netty.channel.ChannelHandlerContext;
 import io.netty.channel.ChannelInitializer;
+import io.netty.channel.ChannelPipeline;
 import io.netty.channel.socket.SocketChannel;
+import io.netty.handler.codec.http.HttpObjectAggregator;
+import io.netty.handler.codec.http.HttpRequestDecoder;
+import io.netty.handler.codec.http.HttpResponseEncoder;
+import io.netty.handler.codec.http.HttpServerUpgradeHandler;
+import io.netty.handler.codec.http2.Http2ServerUpgradeCodec;
 import io.netty.handler.ssl.SslContext;
 
+import java.util.Arrays;
+
 /**
- * Sets up the Netty pipeline
+ * Sets up the Netty pipeline for the example server. Depending on the endpoint config, sets up the
+ * pipeline for NPN or cleartext HTTP upgrade to HTTP/2.
  */
 public class Http2ServerInitializer extends ChannelInitializer<SocketChannel> {
-
     private final SslContext sslCtx;
 
     public Http2ServerInitializer(SslContext sslCtx) {
@@ -33,6 +44,63 @@ public class Http2ServerInitializer extends ChannelInitializer<SocketChannel> {
 
     @Override
     public void initChannel(SocketChannel ch) throws Exception {
+        if (sslCtx != null) {
+            configureSsl(ch);
+        } else {
+            configureClearText(ch);
+        }
+    }
+
+    /**
+     * Configure the pipeline for TLS NPN negotiation to HTTP/2.
+     */
+    private void configureSsl(SocketChannel ch) {
         ch.pipeline().addLast(sslCtx.newHandler(ch.alloc()), new Http2OrHttpHandler());
     }
+
+    /**
+     * Configure the pipeline for a cleartext upgrade from HTTP to HTTP/2.
+     */
+    private void configureClearText(SocketChannel ch) {
+        HttpCodec sourceCodec = new HttpCodec();
+        HttpServerUpgradeHandler.UpgradeCodec upgradeCodec =
+                new Http2ServerUpgradeCodec(new HelloWorldHttp2Handler());
+        HttpServerUpgradeHandler upgradeHandler =
+                new HttpServerUpgradeHandler(sourceCodec, Arrays.asList(upgradeCodec), 65536);
+
+        ch.pipeline().addLast(sourceCodec);
+        ch.pipeline().addLast(upgradeHandler);
+        ch.pipeline().addLast(new UserEventLogger());
+    }
+
+    /**
+     * Source codec for HTTP cleartext upgrade.
+     */
+    private static final class HttpCodec extends ChannelHandlerAppender implements
+            HttpServerUpgradeHandler.SourceCodec {
+        HttpCodec() {
+            add("httpRequestDecoder", new HttpRequestDecoder());
+            add("httpResponseEncoder", new HttpResponseEncoder());
+            add("httpRequestAggregator", new HttpObjectAggregator(65536));
+        }
+
+        @Override
+        public void upgradeFrom(ChannelHandlerContext ctx) {
+            System.out.println("removing HTTP handlers");
+            ctx.pipeline().remove("httpRequestAggregator");
+            ctx.pipeline().remove("httpResponseEncoder");
+            ctx.pipeline().remove("httpRequestDecoder");
+        }
+    }
+
+    /**
+     * Class that logs any User Events triggered on this channel.
+     */
+    private static class UserEventLogger extends ChannelHandlerAdapter {
+        @Override
+        public void userEventTriggered(ChannelHandlerContext ctx, Object evt) throws Exception {
+            System.out.println("User Event Triggered: " + evt);
+            super.userEventTriggered(ctx, evt);
+        }
+    }
 }