* Better method naming

* Added HttpContentEncoder and HttpContentCompressor (needs javadoc update)

src/main/java/org/jboss/netty/handler/codec/http/HttpContentCompressor.java

@@ -0,0 +1,98 @@
+/*
+ * Copyright 2009 Red Hat, Inc.
+ *
+ * Red Hat 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 org.jboss.netty.handler.codec.http;
+
+import org.jboss.netty.buffer.ChannelBuffer;
+import org.jboss.netty.channel.ChannelPipeline;
+import org.jboss.netty.channel.ChannelPipelineCoverage;
+import org.jboss.netty.handler.codec.compression.ZlibEncoder;
+import org.jboss.netty.handler.codec.compression.ZlibWrapper;
+import org.jboss.netty.handler.codec.embedder.EncoderEmbedder;
+
+/**
+ * Decompresses an {@link HttpMessage} and an {@link HttpChunk} compressed in
+ * {@code gzip} or {@code deflate} encoding.  Insert this handler after
+ * {@link HttpMessageDecoder} in the {@link ChannelPipeline}:
+ * <pre>
+ * ChannelPipeline p = ...;
+ * ...
+ * p.addLast("decoder", new HttpRequestDecoder());
+ * p.addLast("inflater", <b>new HttpContentDecomperssor()</b>);
+ * ...
+ * p.addLast("encoder", new HttpResponseEncoder());
+ * p.addLast("handler", new HttpRequestHandler());
+ * </pre>
+ *
+ * @author The Netty Project (netty-dev@lists.jboss.org)
+ * @author Trustin Lee (tlee@redhat.com)
+ * @version $Rev$, $Date$
+ */
+@ChannelPipelineCoverage("one")
+public class HttpContentCompressor extends HttpContentEncoder {
+
+    private final int compressionLevel;
+
+    public HttpContentCompressor() {
+        this(6);
+    }
+
+    public HttpContentCompressor(int compressionLevel) {
+        if (compressionLevel < 0 || compressionLevel > 9) {
+            throw new IllegalArgumentException(
+                    "compressionLevel: " + compressionLevel +
+                    " (expected: 0-9)");
+        }
+        this.compressionLevel = compressionLevel;
+    }
+
+    @Override
+    protected EncoderEmbedder<ChannelBuffer> newContentEncoder(String acceptEncoding) throws Exception {
+        ZlibWrapper wrapper = determineWrapper(acceptEncoding);
+        if (wrapper == null) {
+            return null;
+        }
+
+        return new EncoderEmbedder<ChannelBuffer>(new ZlibEncoder(wrapper, compressionLevel));
+    }
+
+    @Override
+    protected String getTargetContentEncoding(String acceptEncoding) throws Exception {
+        ZlibWrapper wrapper = determineWrapper(acceptEncoding);
+        if (wrapper == null) {
+            return null;
+        }
+
+        switch (wrapper) {
+        case GZIP:
+            return "gzip";
+        case ZLIB:
+            return "deflate";
+        default:
+            throw new Error();
+        }
+    }
+
+    private ZlibWrapper determineWrapper(String acceptEncoding) {
+        // FIXME: Use the Q value.
+        if (acceptEncoding.indexOf("gzip") >= 0) {
+            return ZlibWrapper.GZIP;
+        }
+        if (acceptEncoding.indexOf("deflate") >= 0) {
+            return ZlibWrapper.ZLIB;
+        }
+        return null;
+    }
+}

src/main/java/org/jboss/netty/handler/codec/http/HttpContentDecoder.java

@@ -28,15 +28,15 @@ import org.jboss.netty.handler.codec.embedder.DecoderEmbedder;
  * Decodes the content of the received {@link HttpMessage} and {@link HttpChunk}.
  * The original content ({@link HttpMessage#getContent()} or {@link HttpChunk#getContent()})
  * is replaced with the new content decoded by the {@link DecoderEmbedder},
- * which is created by {@link #newDecoder(String)}.  Once decoding is finished,
+ * which is created by {@link #newContentDecoder(String)}.  Once decoding is finished,
  * the value of the <tt>'Content-Encoding'</tt> header is set to <tt>'identity'</tt>
  * and the <tt>'Content-Length'</tt> header is updated to the length of the
  * decoded content.  If the content encoding of the original is not supported
- * by the decoder, {@link #newDecoder(String)} returns {@code null} and no
+ * by the decoder, {@link #newContentDecoder(String)} returns {@code null} and no
  * decoding occurs (i.e. pass-through).
  * <p>
  * Please note that this is an abstract class.  You have to extend this class
- * and implement {@link #newDecoder(String)} properly to make this class
+ * and implement {@link #newContentDecoder(String)} properly to make this class
  * functional.  For example, refer to the source code of {@link HttpContentDecompressor}.
  *
  * @author The Netty Project (netty-dev@lists.jboss.org)
@@ -46,7 +46,6 @@ import org.jboss.netty.handler.codec.embedder.DecoderEmbedder;
 @ChannelPipelineCoverage("one")
 public abstract class HttpContentDecoder extends SimpleChannelUpstreamHandler {
 
-    private volatile HttpMessage previous;
     private volatile DecoderEmbedder<ChannelBuffer> decoder;
 
     /**
@@ -63,11 +62,6 @@ public abstract class HttpContentDecoder extends SimpleChannelUpstreamHandler {
             HttpMessage m = (HttpMessage) msg;
 
             decoder = null;
-            if (m.isChunked()) {
-                previous = m;
-            } else {
-                previous = null;
-            }
 
             // Determine the content encoding.
             String contentEncoding = m.getHeader(HttpHeaders.Names.CONTENT_ENCODING);
@@ -77,22 +71,20 @@ public abstract class HttpContentDecoder extends SimpleChannelUpstreamHandler {
                 contentEncoding = HttpHeaders.Values.IDENTITY;
             }
 
-            if ((decoder = newDecoder(contentEncoding)) != null) {
+            if ((decoder = newContentDecoder(contentEncoding)) != null) {
                 // Decode the content and remove or replace the existing headers
                 // so that the message looks like a decoded message.
                 m.setHeader(
                         HttpHeaders.Names.CONTENT_ENCODING,
-                        getTargetEncoding(contentEncoding));
+                        getTargetContentEncoding(contentEncoding));
 
                 if (!m.isChunked()) {
                     ChannelBuffer content = m.getContent();
-                    if (content.readable()) {
                     // Decode the content
                     content = ChannelBuffers.wrappedBuffer(
                             decode(content), finishDecode());
 
-                        // Replace the content if necessary.
+                    // Replace the content.
-                        if (content != null) {
                     m.setContent(content);
                     if (m.containsHeader(HttpHeaders.Names.CONTENT_LENGTH)) {
                         m.setHeader(
@@ -101,14 +93,10 @@ public abstract class HttpContentDecoder extends SimpleChannelUpstreamHandler {
                     }
                 }
             }
-                }
-            }
 
             // Because HttpMessage is a mutable object, we can simply forward the received event.
             ctx.sendUpstream(e);
         } else if (msg instanceof HttpChunk) {
-            assert previous != null;
-
             HttpChunk c = (HttpChunk) msg;
             ChannelBuffer content = c.getContent();
 
@@ -124,8 +112,6 @@ public abstract class HttpContentDecoder extends SimpleChannelUpstreamHandler {
                     }
                 } else {
                     ChannelBuffer lastProduct = finishDecode();
-                    previous = null;
-                    decoder = null;
 
                     // Generate an additional chunk if the decoder produced
                     // the last product on closure,
@@ -154,7 +140,7 @@ public abstract class HttpContentDecoder extends SimpleChannelUpstreamHandler {
      *         {@code null} otherwise (alternatively, you can throw an exception
      *         to block unknown encoding).
      */
-    protected abstract DecoderEmbedder<ChannelBuffer> newDecoder(String contentEncoding) throws Exception;
+    protected abstract DecoderEmbedder<ChannelBuffer> newContentDecoder(String contentEncoding) throws Exception;
 
     /**
      * Returns the expected content encoding of the decoded content.
@@ -164,7 +150,7 @@ public abstract class HttpContentDecoder extends SimpleChannelUpstreamHandler {
      * @param contentEncoding the content encoding of the original content
      * @return the expected content encoding of the new content
      */
-    protected String getTargetEncoding(String contentEncoding) throws Exception {
+    protected String getTargetContentEncoding(String contentEncoding) throws Exception {
         return HttpHeaders.Values.IDENTITY;
     }
 
@@ -174,10 +160,13 @@ public abstract class HttpContentDecoder extends SimpleChannelUpstreamHandler {
     }
 
     private ChannelBuffer finishDecode() {
+        ChannelBuffer result;
         if (decoder.finish()) {
-            return ChannelBuffers.wrappedBuffer(decoder.pollAll(new ChannelBuffer[decoder.size()]));
+            result = ChannelBuffers.wrappedBuffer(decoder.pollAll(new ChannelBuffer[decoder.size()]));
         } else {
-            return ChannelBuffers.EMPTY_BUFFER;
+            result = ChannelBuffers.EMPTY_BUFFER;
         }
+        decoder = null;
+        return result;
     }
 }

src/main/java/org/jboss/netty/handler/codec/http/HttpContentDecompressor.java

@@ -43,7 +43,7 @@ import org.jboss.netty.handler.codec.embedder.DecoderEmbedder;
 @ChannelPipelineCoverage("one")
 public class HttpContentDecompressor extends HttpContentDecoder {
     @Override
-    protected DecoderEmbedder<ChannelBuffer> newDecoder(String contentEncoding) throws Exception {
+    protected DecoderEmbedder<ChannelBuffer> newContentDecoder(String contentEncoding) throws Exception {
         if ("gzip".equalsIgnoreCase(contentEncoding) || "x-gzip".equalsIgnoreCase(contentEncoding)) {
             return new DecoderEmbedder<ChannelBuffer>(new ZlibDecoder(ZlibWrapper.GZIP));
         } else if ("deflate".equalsIgnoreCase(contentEncoding) || "x-deflate".equalsIgnoreCase(contentEncoding)) {

src/main/java/org/jboss/netty/handler/codec/http/HttpContentEncoder.java

@@ -0,0 +1,179 @@
+/*
+ * Copyright 2009 Red Hat, Inc.
+ *
+ * Red Hat 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 org.jboss.netty.handler.codec.http;
+
+import java.util.Queue;
+
+import org.jboss.netty.buffer.ChannelBuffer;
+import org.jboss.netty.buffer.ChannelBuffers;
+import org.jboss.netty.channel.ChannelHandlerContext;
+import org.jboss.netty.channel.Channels;
+import org.jboss.netty.channel.MessageEvent;
+import org.jboss.netty.channel.SimpleChannelHandler;
+import org.jboss.netty.handler.codec.embedder.DecoderEmbedder;
+import org.jboss.netty.handler.codec.embedder.EncoderEmbedder;
+import org.jboss.netty.util.internal.LinkedTransferQueue;
+
+/**
+ *
+ * @author The Netty Project (netty-dev@lists.jboss.org)
+ * @author Trustin Lee (tlee@redhat.com)
+ * @version $Rev$, $Date$
+ */
+public abstract class HttpContentEncoder extends SimpleChannelHandler {
+
+    private final Queue<String> acceptEncodingQueue = new LinkedTransferQueue<String>();
+    private volatile EncoderEmbedder<ChannelBuffer> encoder;
+
+    /**
+     * Creates a new instance.
+     */
+    protected HttpContentEncoder() {
+        super();
+    }
+
+    @Override
+    public void messageReceived(ChannelHandlerContext ctx, MessageEvent e)
+            throws Exception {
+        Object msg = e.getMessage();
+        if (!(msg instanceof HttpMessage)) {
+            ctx.sendUpstream(e);
+            return;
+        }
+
+        HttpMessage m = (HttpMessage) msg;
+        String acceptedEncoding = m.getHeader(HttpHeaders.Names.ACCEPT_ENCODING);
+        if (acceptedEncoding == null) {
+            acceptedEncoding = HttpHeaders.Values.IDENTITY;
+        }
+        acceptEncodingQueue.offer(acceptedEncoding);
+
+        ctx.sendUpstream(e);
+    }
+
+    @Override
+    public void writeRequested(ChannelHandlerContext ctx, MessageEvent e)
+            throws Exception {
+
+        Object msg = e.getMessage();
+        if (msg instanceof HttpMessage) {
+            HttpMessage m = (HttpMessage) msg;
+
+            encoder = null;
+
+            // Determine the content encoding.
+            String acceptEncoding = acceptEncodingQueue.poll();
+            if (acceptEncoding == null) {
+                throw new IllegalStateException("cannot send more responses than requests");
+            }
+
+            if ((encoder = newContentEncoder(acceptEncoding)) != null) {
+                // Encode the content and remove or replace the existing headers
+                // so that the message looks like a decoded message.
+                m.setHeader(
+                        HttpHeaders.Names.CONTENT_ENCODING,
+                        getTargetContentEncoding(acceptEncoding));
+
+                if (!m.isChunked()) {
+                    ChannelBuffer content = m.getContent();
+                    // Encode the content.
+                    content = ChannelBuffers.wrappedBuffer(
+                            encode(content), finishEncode());
+
+                    // Replace the content.
+                    m.setContent(content);
+                    if (m.containsHeader(HttpHeaders.Names.CONTENT_LENGTH)) {
+                        m.setHeader(
+                                HttpHeaders.Names.CONTENT_LENGTH,
+                                Integer.toString(content.readableBytes()));
+                    }
+                }
+            }
+
+            // Because HttpMessage is a mutable object, we can simply forward the write request.
+            ctx.sendDownstream(e);
+        } else if (msg instanceof HttpChunk) {
+            HttpChunk c = (HttpChunk) msg;
+            ChannelBuffer content = c.getContent();
+
+            // Encode the chunk if necessary.
+            if (encoder != null) {
+                if (!c.isLast()) {
+                    content = encode(content);
+                    if (content.readable()) {
+                        // Note that HttpChunk is immutable unlike HttpMessage.
+                        // XXX API inconsistency? I can live with it though.
+                        Channels.write(
+                                ctx, e.getFuture(), new DefaultHttpChunk(content), e.getRemoteAddress());
+                    }
+                } else {
+                    ChannelBuffer lastProduct = finishEncode();
+
+                    // Generate an additional chunk if the decoder produced
+                    // the last product on closure,
+                    if (lastProduct.readable()) {
+                        Channels.write(
+                                ctx, Channels.succeededFuture(e.getChannel()), new DefaultHttpChunk(lastProduct), e.getRemoteAddress());
+                    }
+
+                    // Emit the last chunk.
+                    ctx.sendDownstream(e);
+                }
+            } else {
+                ctx.sendDownstream(e);
+            }
+        } else {
+            ctx.sendDownstream(e);
+        }
+    }
+
+    /**
+     * Returns a new {@link EncoderEmbedder} that encodes the HTTP message
+     * content.
+     *
+     * @param acceptEncoding
+     *        the value of the {@code "Accept-Encoding"} header.
+     *
+     * @return a new {@link DecoderEmbedder} if the specified encoding is supported.
+     *         {@code null} otherwise (alternatively, you can throw an exception
+     *         to block unknown encoding).
+     */
+    protected abstract EncoderEmbedder<ChannelBuffer> newContentEncoder(String acceptEncoding) throws Exception;
+
+    /**
+     * Returns the expected content encoding of the encoded content.
+     *
+     * @param contentEncoding the content encoding of the original content
+     * @return the expected content encoding of the new content
+     */
+    protected abstract String getTargetContentEncoding(String acceptEncoding) throws Exception;
+
+    private ChannelBuffer encode(ChannelBuffer buf) {
+        encoder.offer(buf);
+        return ChannelBuffers.wrappedBuffer(encoder.pollAll(new ChannelBuffer[encoder.size()]));
+    }
+
+    private ChannelBuffer finishEncode() {
+        ChannelBuffer result;
+        if (encoder.finish()) {
+            result = ChannelBuffers.wrappedBuffer(encoder.pollAll(new ChannelBuffer[encoder.size()]));
+        } else {
+            result = ChannelBuffers.EMPTY_BUFFER;
+        }
+        encoder = null;
+        return result;
+    }
+}