Fixed issue: NETTY-359 Missing support for HTTP 'Expect: 100-continue' header.

* Improved HttpHeaders.is100ContinueExpected() to conform to the RFC
* HttpChunkAggregator now sends "HTTP/1.1 100 Continue" response automatically.
* Added some TODO items which should be done in 4.0.

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

@@ -15,6 +15,9 @@
  */
 package org.jboss.netty.handler.codec.http;
 
+import static org.jboss.netty.channel.Channels.*;
+import static org.jboss.netty.handler.codec.http.HttpHeaders.*;
+
 import java.util.List;
 import java.util.Map.Entry;
 
@@ -27,6 +30,7 @@ import org.jboss.netty.channel.Channels;
 import org.jboss.netty.channel.MessageEvent;
 import org.jboss.netty.channel.SimpleChannelUpstreamHandler;
 import org.jboss.netty.handler.codec.frame.TooLongFrameException;
+import org.jboss.netty.util.CharsetUtil;
 
 /**
  * A {@link ChannelHandler} that aggregates an {@link HttpMessage}
@@ -53,6 +57,9 @@ import org.jboss.netty.handler.codec.frame.TooLongFrameException;
  */
 public class HttpChunkAggregator extends SimpleChannelUpstreamHandler {
 
+    private static final ChannelBuffer CONTINUE = ChannelBuffers.copiedBuffer(
+            "HTTP/1.1 100 Continue\r\n\r\n", CharsetUtil.US_ASCII);
+
     private final int maxContentLength;
     private HttpMessage currentMessage;
 
@@ -82,6 +89,16 @@ public class HttpChunkAggregator extends SimpleChannelUpstreamHandler {
 
         if (msg instanceof HttpMessage) {
             HttpMessage m = (HttpMessage) msg;
+
+            // Handle the 'Expect: 100-continue' header if necessary.
+            // TODO: Respond with 413 Request Entity Too Large
+            //   and discard the traffic or close the connection.
+            //       No need to notify the upstream handlers - just log.
+            //       If decoding a response, just throw an exception.
+            if (is100ContinueExpected(m)) {
+                write(ctx, succeededFuture(ctx.getChannel()), CONTINUE.duplicate());
+            }
+
             if (m.isChunked()) {
                 // A chunked message - remove 'Transfer-Encoding' header,
                 // initialize the cumulative buffer, and wait for incoming chunks.
@@ -111,6 +128,10 @@ public class HttpChunkAggregator extends SimpleChannelUpstreamHandler {
             ChannelBuffer content = currentMessage.getContent();
 
             if (content.readableBytes() > maxContentLength - chunk.getContent().readableBytes()) {
+                // TODO: Respond with 413 Request Entity Too Large
+                //   and discard the traffic or close the connection.
+                //       No need to notify the upstream handlers - just log.
+                //       If decoding a response, just throw an exception.
                 throw new TooLongFrameException(
                         "HTTP content length exceeded " + maxContentLength +
                         " bytes.");

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

@@ -679,6 +679,16 @@ public class HttpHeaders {
      * {@code "Expect: 100-continue"} header.
      */
     public static boolean is100ContinueExpected(HttpMessage message) {
+        // Expect: 100-continue is for requests only.
+        if (!(message instanceof HttpRequest)) {
+            return false;
+        }
+
+        // It works only on HTTP/1.1 or later.
+        if (message.getProtocolVersion().compareTo(HttpVersion.HTTP_1_1) < 0) {
+            return false;
+        }
+
         // In most cases, there will be one or zero 'Expect' header.
         String value = message.getHeader(Names.EXPECT);
         if (value == null) {

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

@@ -536,6 +536,10 @@ public abstract class HttpMessageDecoder extends ReplayingDecoder<HttpMessageDec
 
             // Abort decoding if the header part is too large.
             if (headerSize >= maxHeaderSize) {
+                // TODO: Respond with Bad Request and discard the traffic
+                //    or close the connection.
+                //       No need to notify the upstream handlers - just log.
+                //       If decoding a response, just throw an exception.
                 throw new TooLongFrameException(
                         "HTTP header is larger than " +
                         maxHeaderSize + " bytes.");
@@ -581,6 +585,10 @@ public abstract class HttpMessageDecoder extends ReplayingDecoder<HttpMessageDec
             }
             else {
                 if (lineLength >= maxLineLength) {
+                    // TODO: Respond with Bad Request and discard the traffic
+                    //    or close the connection.
+                    //       No need to notify the upstream handlers - just log.
+                    //       If decoding a response, just throw an exception.
                     throw new TooLongFrameException(
                             "An HTTP line is larger than " + maxLineLength +
                             " bytes.");