Review comments

Author: dagnir

core/http-auth-aws/src/main/java/software/amazon/awssdk/http/auth/aws/internal/signer/chunkedencoding/ChunkedEncodedPublisher.java

@@ -133,7 +133,7 @@ public Publisher<ByteBuffer> map(Publisher<ByteBuffer> upstream, Function<? supe
 
     private ByteBuffer encodeChunk(ByteBuffer byteBuffer) {
         int contentLen = byteBuffer.remaining();
-        byte[] chunkSizeHex = Integer.toHexString(contentLen).getBytes(StandardCharsets.UTF_8);
+        byte[] chunkSizeHex = Integer.toHexString(byteBuffer.remaining()).getBytes(StandardCharsets.UTF_8);
 
         List<Pair<byte[], byte[]>> chunkExtensions = this.extensions.stream()
                                                                     .map(e -> {
@@ -152,10 +152,18 @@ private ByteBuffer encodeChunk(ByteBuffer byteBuffer) {
             trailerData = Collections.emptyList();
         }
 
-        int trailerLen = trailerData.stream().mapToInt(t -> t.remaining() + 2).sum();
+        //
+        int trailerLen = trailerData.stream()
+                                    // + 2 for each CRLF that ends the header-field
+                                    .mapToInt(t -> t.remaining() + 2)
+                                    .sum();
 
         int encodedLen = chunkSizeHex.length + extensionsLength + CRLF.length + contentLen + trailerLen + CRLF.length;
 
+        if (isTrailerChunk) {
+            encodedLen += CRLF.length;
+        }
+
         ByteBuffer encoded = ByteBuffer.allocate(encodedLen);
 
         encoded.put(chunkSizeHex); // chunk-size
@@ -181,6 +189,7 @@ private ByteBuffer encodeChunk(ByteBuffer byteBuffer) {
                 encoded.put(t);
                 encoded.put(CRLF);
             });
+            encoded.put(CRLF);
         }
 
         encoded.flip();

core/http-auth-aws/src/test/java/software/amazon/awssdk/http/auth/aws/internal/signer/chunkedencoding/ChunkedEncodedPublisherTest.java

@@ -48,6 +48,29 @@ public void setup() {
         CRC32.reset();
     }
 
+    @Test
+    public void subscribe_publisherEmpty_onlyProducesTrailer() {
+        Publisher<ByteBuffer> emptyPublisher = Flowable.empty();
+
+        ChunkedEncodedPublisher build = newChunkedBuilder(emptyPublisher)
+            .addTrailer(() -> Pair.of("foo", Collections.singletonList("1")))
+            .addTrailer(() -> Pair.of("bar", Collections.singletonList("2")))
+            .addEmptyTrailingChunk(true)
+            .build();
+
+        List<ByteBuffer> chunks = getAllElements(build);
+
+        assertThat(chunks.size()).isEqualTo(1);
+
+        String trailerAsString = StandardCharsets.UTF_8.decode(chunks.get(0)).toString();
+
+        assertThat(trailerAsString).isEqualTo(
+            "0\r\n" +
+            "foo:1\r\n" +
+            "bar:2\r\n" +
+            "\r\n");
+    }
+
     @Test
     void subscribe_trailerProviderPresent_trailerPartAdded() {
         TestPublisher upstream = randomPublisherOfLength(8);
@@ -121,7 +144,8 @@ void subscribe_trailerPresent_trailerFormattedCorrectly() {
         ByteBuffer last = chunks.get(chunks.size() - 1);
 
         String expected = "0\r\n" +
-                          "foo:bar\r\n";
+                          "foo:bar\r\n" +
+                          "\r\n";
 
         assertThat(chunkAsString(last)).isEqualTo(expected);
     }