HttpContentDecompressor should change decompressed requests to chunked encoding. Fixes issue #5428

`HttpContentDecoder` was removing `Content-Length` header but not adding a `Transfer-Encoding` header which goes against the HTTP spec.

Added `Transfer-Encoding` header with value `chunked` when `Content-Length` is removed.
Modified existing unit test to also check for this condition.

Compliance with HTTP spec.

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

@@ -99,6 +99,7 @@ public abstract class HttpContentDecoder extends MessageToMessageDecoder<HttpObj
             // If buffering is not an issue, add HttpObjectAggregator down the chain, it will set the header.
             // Otherwise, rely on LastHttpContent message.
             headers.remove(HttpHeaderNames.CONTENT_LENGTH);
+            headers.set(HttpHeaderNames.TRANSFER_ENCODING, HttpHeaderValues.CHUNKED);
 
             // set new content encoding,
             CharSequence targetContentEncoding = getTargetContentEncoding(contentEncoding);

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

@@ -299,9 +299,12 @@ public class HttpContentDecoderTest {
         Object o = resp.peek();
         assertThat(o, is(instanceOf(HttpResponse.class)));
         HttpResponse r = (HttpResponse) o;
-        String v = r.headers().get(HttpHeaderNames.CONTENT_LENGTH);
+
-        Long value = v == null ? null : Long.parseLong(v);
+        assertFalse("Content-Length header not removed.", r.headers().contains(HttpHeaderNames.CONTENT_LENGTH));
-        assertTrue(value == null || value.longValue() == HELLO_WORLD.length());
+
+        String transferEncoding = r.headers().get(HttpHeaderNames.TRANSFER_ENCODING);
+        assertNotNull("Content-length as well as transfer-encoding not set.", transferEncoding);
+        assertEquals("Unexpected transfer-encoding value.", HttpHeaderValues.CHUNKED.toString(), transferEncoding);
 
         assertHasInboundMessages(channel, true);
         assertHasOutboundMessages(channel, false);
@@ -354,24 +357,9 @@ public class HttpContentDecoderTest {
         Queue<Object> req = channel.inboundMessages();
         assertTrue(req.size() > 1);
         int contentLength = 0;
-        for (Object o : req) {
+        contentLength = calculateContentLength(req, contentLength);
-            if (o instanceof HttpContent) {
-                assertTrue(((HttpContent) o).refCnt() > 0);
-                ByteBuf b = ((HttpContent) o).content();
-                contentLength += b.readableBytes();
-            }
-        }
 
-        int readCount = 0;
+        byte[] receivedContent = readContent(req, contentLength);
-        byte[] receivedContent = new byte[contentLength];
-        for (Object o : req) {
-            if (o instanceof HttpContent) {
-                ByteBuf b = ((HttpContent) o).content();
-                int readableBytes = b.readableBytes();
-                b.readBytes(receivedContent, readCount, readableBytes);
-                readCount += readableBytes;
-            }
-        }
 
         assertEquals(HELLO_WORLD, new String(receivedContent, CharsetUtil.US_ASCII));
 
@@ -396,24 +384,9 @@ public class HttpContentDecoderTest {
         Queue<Object> resp = channel.inboundMessages();
         assertTrue(resp.size() > 1);
         int contentLength = 0;
-        for (Object o : resp) {
+        contentLength = calculateContentLength(resp, contentLength);
-            if (o instanceof HttpContent) {
-                assertTrue(((HttpContent) o).refCnt() > 0);
-                ByteBuf b = ((HttpContent) o).content();
-                contentLength += b.readableBytes();
-            }
-        }
 
-        int readCount = 0;
+        byte[] receivedContent = readContent(resp, contentLength);
-        byte[] receivedContent = new byte[contentLength];
-        for (Object o : resp) {
-            if (o instanceof HttpContent) {
-                ByteBuf b = ((HttpContent) o).content();
-                int readableBytes = b.readableBytes();
-                b.readBytes(receivedContent, readCount, readableBytes);
-                readCount += readableBytes;
-            }
-        }
 
         assertEquals(HELLO_WORLD, new String(receivedContent, CharsetUtil.US_ASCII));
 
@@ -422,7 +395,7 @@ public class HttpContentDecoderTest {
         assertFalse(channel.finish());
     }
 
-    private byte[] gzDecompress(byte[] input) {
+    private static byte[] gzDecompress(byte[] input) {
         ZlibDecoder decoder = ZlibCodecFactory.newZlibDecoder(ZlibWrapper.GZIP);
         EmbeddedChannel channel = new EmbeddedChannel(decoder);
         assertTrue(channel.writeInbound(Unpooled.wrappedBuffer(input)));
@@ -448,7 +421,32 @@ public class HttpContentDecoderTest {
         return output;
     }
 
-    private byte[] gzCompress(byte[] input) {
+    private static byte[] readContent(Queue<Object> req, int contentLength) {
+        byte[] receivedContent = new byte[contentLength];
+        int readCount = 0;
+        for (Object o : req) {
+            if (o instanceof HttpContent) {
+                ByteBuf b = ((HttpContent) o).content();
+                int readableBytes = b.readableBytes();
+                b.readBytes(receivedContent, readCount, readableBytes);
+                readCount += readableBytes;
+            }
+        }
+        return receivedContent;
+    }
+
+    private static int calculateContentLength(Queue<Object> req, int contentLength) {
+        for (Object o : req) {
+            if (o instanceof HttpContent) {
+                assertTrue(((HttpContent) o).refCnt() > 0);
+                ByteBuf b = ((HttpContent) o).content();
+                contentLength += b.readableBytes();
+            }
+        }
+        return contentLength;
+    }
+
+    private static byte[] gzCompress(byte[] input) {
         ZlibEncoder encoder = ZlibCodecFactory.newZlibEncoder(ZlibWrapper.GZIP);
         EmbeddedChannel channel = new EmbeddedChannel(encoder);
         assertTrue(channel.writeOutbound(Unpooled.wrappedBuffer(input)));
@@ -474,7 +472,7 @@ public class HttpContentDecoderTest {
         return output;
     }
 
-    private void assertHasInboundMessages(EmbeddedChannel channel, boolean hasMessages) {
+    private static void assertHasInboundMessages(EmbeddedChannel channel, boolean hasMessages) {
         Object o;
         if (hasMessages) {
             while (true) {
@@ -491,7 +489,7 @@ public class HttpContentDecoderTest {
         }
     }
 
-    private void assertHasOutboundMessages(EmbeddedChannel channel, boolean hasMessages) {
+    private static void assertHasOutboundMessages(EmbeddedChannel channel, boolean hasMessages) {
         Object o;
         if (hasMessages) {
             while (true) {