HttpObjectAggregator doesn't check content-length header

Motivation:
The HttpObjectAggregator always responds with a 100-continue response. It should check the Content-Length header to see if the content length is OK, and if not responds with a 417.

Modifications:
- HttpObjectAggregator checks the Content-Length header in the case of a 100-continue.

Result:
HttpObjectAggregator responds with 417 if content is known to be too big.

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

@@ -0,0 +1,25 @@
+/*
+ * Copyright 2015 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;
+
+/**
+ * A user event designed to communicate that a expectation has failed and there should be no expectation that a
+ * body will follow.
+ */
+public final class HttpExpectationFailedEvent {
+    public static final HttpExpectationFailedEvent INSTANCE = new HttpExpectationFailedEvent();
+    private HttpExpectationFailedEvent() { }
+}

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

@@ -135,6 +135,16 @@ public static long getContentLength(HttpMessage message, long defaultValue) {
         return defaultValue;
     }
 
+    /**
+     * Get an {@code int} representation of {@link #getContentLength(HttpMessage, long)}.
+     * @return the content length or {@code defaultValue} if this message does
+     *         not have the {@code "Content-Length"} header or its value is not
+     *         a number. Not to exceed the boundaries of integer.
+     */
+    public static int getContentLength(HttpMessage message, int defaultValue) {
+        return (int) Math.min(Integer.MAX_VALUE, HttpHeaderUtil.getContentLength(message, (long) defaultValue));
+    }
+
     /**
      * Returns the content length of the specified web socket message.  If the
      * specified message is not a web socket message, {@code -1} is returned.

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

@@ -29,6 +29,9 @@
 import io.netty.util.internal.logging.InternalLogger;
 import io.netty.util.internal.logging.InternalLoggerFactory;
 
+import static io.netty.handler.codec.http.HttpHeaderNames.CONTENT_LENGTH;
+import static io.netty.handler.codec.http.HttpHeaderUtil.getContentLength;
+
 /**
  * A {@link ChannelHandler} that aggregates an {@link HttpMessage}
  * and its following {@link HttpContent}s into a single {@link FullHttpRequest}
@@ -50,28 +53,43 @@
  */
 public class HttpObjectAggregator
         extends MessageAggregator<HttpObject, HttpMessage, HttpContent, FullHttpMessage> {
-
     private static final InternalLogger logger = InternalLoggerFactory.getInstance(HttpObjectAggregator.class);
-    private static final FullHttpResponse CONTINUE = new DefaultFullHttpResponse(
-            HttpVersion.HTTP_1_1, HttpResponseStatus.CONTINUE, Unpooled.EMPTY_BUFFER);
+    private static final FullHttpResponse CONTINUE =
+            new DefaultFullHttpResponse(HttpVersion.HTTP_1_1, HttpResponseStatus.CONTINUE, Unpooled.EMPTY_BUFFER);
+    private static final FullHttpResponse EXPECTATION_FAILED = new DefaultFullHttpResponse(
+            HttpVersion.HTTP_1_1, HttpResponseStatus.EXPECTATION_FAILED, Unpooled.EMPTY_BUFFER);
     private static final FullHttpResponse TOO_LARGE = new DefaultFullHttpResponse(
             HttpVersion.HTTP_1_1, HttpResponseStatus.REQUEST_ENTITY_TOO_LARGE, Unpooled.EMPTY_BUFFER);
 
     static {
-        TOO_LARGE.headers().set(HttpHeaderNames.CONTENT_LENGTH, 0);
+        EXPECTATION_FAILED.headers().set(CONTENT_LENGTH, 0);
+        TOO_LARGE.headers().set(CONTENT_LENGTH, 0);
     }
 
+    private final boolean closeOnExpectationFailed;
+
     /**
      * Creates a new instance.
-     *
-     * @param maxContentLength
-     *        the maximum length of the aggregated content in bytes.
-     *        If the length of the aggregated content exceeds this value,
-     *        {@link #handleOversizedMessage(ChannelHandlerContext, HttpMessage)}
-     *        will be called.
+     * @param maxContentLength the maximum length of the aggregated content in bytes.
+     * If the length of the aggregated content exceeds this value,
+     * {@link #handleOversizedMessage(ChannelHandlerContext, HttpMessage)} will be called.
      */
     public HttpObjectAggregator(int maxContentLength) {
+        this(maxContentLength, false);
+    }
+
+    /**
+     * Creates a new instance.
+     * @param maxContentLength the maximum length of the aggregated content in bytes.
+     * If the length of the aggregated content exceeds this value,
+     * {@link #handleOversizedMessage(ChannelHandlerContext, HttpMessage)} will be called.
+     * @param closeOnExpectationFailed If a 100-continue response is detected but the content length is too large
+     * then {@code true} means close the connection. otherwise the connection will remain open and data will be
+     * consumed and discarded until the next request is received.
+     */
+    public HttpObjectAggregator(int maxContentLength, boolean closeOnExpectationFailed) {
         super(maxContentLength);
+        this.closeOnExpectationFailed = closeOnExpectationFailed;
     }
 
     @Override
@@ -95,22 +113,32 @@ protected boolean isAggregated(HttpObject msg) throws Exception {
     }
 
     @Override
-    protected boolean hasContentLength(HttpMessage start) throws Exception {
-        return HttpHeaderUtil.isContentLengthSet(start);
+    protected boolean isContentLengthInvalid(HttpMessage start, int maxContentLength) {
+        return getContentLength(start, -1) > maxContentLength;
+    }
+
+    @Override
+    protected Object newContinueResponse(HttpMessage start, int maxContentLength, ChannelPipeline pipeline) {
+        if (HttpHeaderUtil.is100ContinueExpected(start)) {
+            if (getContentLength(start, -1) <= maxContentLength) {
+                return CONTINUE.duplicate().retain();
+            }
+
+            pipeline.fireUserEventTriggered(HttpExpectationFailedEvent.INSTANCE);
+            return EXPECTATION_FAILED.duplicate().retain();
+        }
+        return null;
     }
 
     @Override
-    protected long contentLength(HttpMessage start) throws Exception {
-        return HttpHeaderUtil.getContentLength(start);
+    protected boolean closeAfterContinueResponse(Object msg) {
+        return closeOnExpectationFailed && ignoreContentAfterContinueResponse(msg);
     }
 
     @Override
-    protected Object newContinueResponse(HttpMessage start) throws Exception {
-        if (HttpHeaderUtil.is100ContinueExpected(start)) {
-            return CONTINUE;
-        } else {
-            return null;
-        }
+    protected boolean ignoreContentAfterContinueResponse(Object msg) {
+        return msg instanceof HttpResponse &&
+               ((HttpResponse) msg).status().code() == HttpResponseStatus.EXPECTATION_FAILED.code();
     }
 
     @Override
@@ -157,7 +185,8 @@ protected void finishAggregation(FullHttpMessage aggregated) throws Exception {
     protected void handleOversizedMessage(final ChannelHandlerContext ctx, HttpMessage oversized) throws Exception {
         if (oversized instanceof HttpRequest) {
             // send back a 413 and close the connection
-            ChannelFuture future = ctx.writeAndFlush(TOO_LARGE).addListener(new ChannelFutureListener() {
+            ChannelFuture future = ctx.writeAndFlush(TOO_LARGE.duplicate().retain()).addListener(
+                    new ChannelFutureListener() {
                 @Override
                 public void operationComplete(ChannelFuture future) throws Exception {
                     if (!future.isSuccess()) {

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

@@ -431,6 +431,16 @@ public void userEventTriggered(ChannelHandlerContext ctx, Object evt) throws Exc
             // This method is responsible for ending requests in some situations and must be called
             // when the input has been shutdown.
             super.channelInactive(ctx);
+        } else if (evt instanceof HttpExpectationFailedEvent) {
+            switch (currentState) {
+            case READ_FIXED_LENGTH_CONTENT:
+            case READ_VARIABLE_LENGTH_CONTENT:
+            case READ_CHUNK_SIZE:
+                reset();
+                break;
+            default:
+                break;
+            }
         }
         super.userEventTriggered(ctx, evt);
     }

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

@@ -16,6 +16,7 @@
 package io.netty.handler.codec.http.websocketx;
 
 import io.netty.buffer.ByteBuf;
+import io.netty.channel.ChannelPipeline;
 import io.netty.handler.codec.MessageAggregator;
 import io.netty.handler.codec.TooLongFrameException;
 
@@ -63,18 +64,23 @@ protected boolean isAggregated(WebSocketFrame msg) throws Exception {
     }
 
     @Override
-    protected boolean hasContentLength(WebSocketFrame start) throws Exception {
+    protected boolean isContentLengthInvalid(WebSocketFrame start, int maxContentLength) {
         return false;
     }
 
     @Override
-    protected long contentLength(WebSocketFrame start) throws Exception {
+    protected Object newContinueResponse(WebSocketFrame start, int maxContentLength, ChannelPipeline pipeline) {
+        return null;
+    }
+
+    @Override
+    protected boolean closeAfterContinueResponse(Object msg) throws Exception {
         throw new UnsupportedOperationException();
     }
 
     @Override
-    protected Object newContinueResponse(WebSocketFrame start) throws Exception {
-        return null;
+    protected boolean ignoreContentAfterContinueResponse(Object msg) throws Exception {
+        throw new UnsupportedOperationException();
     }
 
     @Override