Fix a bug where HttpObjectAggregator fails to send a '100 Continue' response

- Fixes #1742

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

@@ -15,22 +15,22 @@
  */
 package io.netty.handler.codec.http;
 
-import static io.netty.handler.codec.http.HttpHeaders.is100ContinueExpected;
-import static io.netty.handler.codec.http.HttpHeaders.removeTransferEncodingChunked;
-import io.netty.buffer.ByteBuf;
 import io.netty.buffer.CompositeByteBuf;
 import io.netty.buffer.Unpooled;
+import io.netty.channel.ChannelFuture;
+import io.netty.channel.ChannelFutureListener;
 import io.netty.channel.ChannelHandler;
 import io.netty.channel.ChannelHandlerContext;
 import io.netty.channel.ChannelPipeline;
 import io.netty.handler.codec.DecoderResult;
 import io.netty.handler.codec.MessageToMessageDecoder;
 import io.netty.handler.codec.TooLongFrameException;
-import io.netty.util.CharsetUtil;
 import io.netty.util.ReferenceCountUtil;
 
 import java.util.List;
 
+import static io.netty.handler.codec.http.HttpHeaders.*;
+
 /**
  * A {@link ChannelHandler} that aggregates an {@link HttpMessage}
  * and its following {@link HttpContent}s into a single {@link HttpMessage} with
@@ -49,8 +49,8 @@ import java.util.List;
  */
 public class HttpObjectAggregator extends MessageToMessageDecoder<HttpObject> {
     public static final int DEFAULT_MAX_COMPOSITEBUFFER_COMPONENTS = 1024;
-    private static final ByteBuf CONTINUE = Unpooled.unreleasableBuffer(Unpooled.copiedBuffer(
+    private static final FullHttpResponse CONTINUE =
-            "HTTP/1.1 100 Continue\r\n\r\n", CharsetUtil.US_ASCII));
+            new DefaultFullHttpResponse(HttpVersion.HTTP_1_1, HttpResponseStatus.CONTINUE, Unpooled.EMPTY_BUFFER);
 
     private final int maxContentLength;
     private FullHttpMessage currentMessage;
@@ -109,7 +109,7 @@ public class HttpObjectAggregator extends MessageToMessageDecoder<HttpObject> {
     }
 
     @Override
-    protected void decode(ChannelHandlerContext ctx, HttpObject msg, List<Object> out) throws Exception {
+    protected void decode(final ChannelHandlerContext ctx, HttpObject msg, List<Object> out) throws Exception {
         FullHttpMessage currentMessage = this.currentMessage;
 
         if (msg instanceof HttpMessage) {
@@ -124,7 +124,14 @@ public class HttpObjectAggregator extends MessageToMessageDecoder<HttpObject> {
             //       No need to notify the upstream handlers - just log.
             //       If decoding a response, just throw an exception.
             if (is100ContinueExpected(m)) {
-                ctx.writeAndFlush(CONTINUE.duplicate());
+                ctx.writeAndFlush(CONTINUE).addListener(new ChannelFutureListener() {
+                    @Override
+                    public void operationComplete(ChannelFuture future) throws Exception {
+                        if (!future.isSuccess()) {
+                            ctx.fireExceptionCaught(future.cause());
+                        }
+                    }
+                });
             }
 
             if (!m.getDecoderResult().isSuccess()) {

codec-http/src/test/java/io/netty/handler/codec/http/HttpServerCodecTest.java

@@ -19,9 +19,12 @@ import io.netty.buffer.ByteBuf;
 import io.netty.buffer.Unpooled;
 import io.netty.channel.embedded.EmbeddedChannel;
 import io.netty.util.CharsetUtil;
-import org.junit.Assert;
 import org.junit.Test;
 
+import static io.netty.handler.codec.http.HttpHeaders.Names.*;
+import static org.hamcrest.CoreMatchers.*;
+import static org.junit.Assert.*;
+
 public class HttpServerCodecTest {
 
     /**
@@ -45,7 +48,7 @@ public class HttpServerCodecTest {
         decoderEmbedder.finish();
 
         HttpMessage httpMessage = (HttpMessage) decoderEmbedder.readInbound();
-        Assert.assertNotNull(httpMessage);
+        assertNotNull(httpMessage);
 
         boolean empty = true;
         int totalBytesPolled = 0;
@@ -56,11 +59,47 @@ public class HttpServerCodecTest {
             }
             empty = false;
             totalBytesPolled += httpChunk.content().readableBytes();
-            Assert.assertFalse(httpChunk instanceof LastHttpContent);
+            assertFalse(httpChunk instanceof LastHttpContent);
             httpChunk.release();
         }
-        Assert.assertFalse(empty);
+        assertFalse(empty);
-        Assert.assertEquals(offeredContentLength, totalBytesPolled);
+        assertEquals(offeredContentLength, totalBytesPolled);
+    }
+
+    @Test
+    public void test100Continue() throws Exception {
+        EmbeddedChannel ch = new EmbeddedChannel(new HttpServerCodec(), new HttpObjectAggregator(1024));
+
+        // Send the request headers.
+        ch.writeInbound(Unpooled.copiedBuffer(
+                "PUT /upload-large HTTP/1.1\r\n" +
+                "Expect: 100-continue\r\n" +
+                "Content-Length: 1\r\n\r\n", CharsetUtil.UTF_8));
+
+        // Ensure the aggregator generates nothing.
+        assertThat(ch.readInbound(), is(nullValue()));
+
+        // Ensure the aggregator writes a 100 Continue response.
+        ByteBuf continueResponse = (ByteBuf) ch.readOutbound();
+        assertThat(continueResponse.toString(CharsetUtil.UTF_8), is("HTTP/1.1 100 Continue\r\n\r\n"));
+
+        // But nothing more.
+        assertThat(ch.readOutbound(), is(nullValue()));
+
+        // Send the content of the request.
+        ch.writeInbound(Unpooled.wrappedBuffer(new byte[] { 42 }));
+
+        // Ensure the aggregator generates a full request.
+        FullHttpRequest req = (FullHttpRequest) ch.readInbound();
+        assertThat(req.headers().get(CONTENT_LENGTH), is("1"));
+        assertThat(req.content().readableBytes(), is(1));
+        assertThat(req.content().readByte(), is((byte) 42));
+        req.release();
+
+        // But nothing more.
+        assertThat(ch.readInbound(), is(nullValue()));
+
+        ch.finish();
     }
 
     private static ByteBuf prepareDataChunk(int size) {