Honor content-length if present in the request

Author: zoewangg

.changes/next-release/bugfix-AWSSDKforJavav2-bbc8ecb.json

@@ -0,0 +1,5 @@
+{
+    "category": "AWS SDK for Java v2", 
+    "type": "bugfix", 
+    "description": "Fix the issue where the `content-length` set on the request is not honored for streaming operations."
+}

core/sdk-core/src/main/java/software/amazon/awssdk/core/internal/transform/AbstractStreamingRequestMarshaller.java

@@ -57,6 +57,11 @@ protected final void addHeaders(SdkHttpFullRequest.Builder marshalled,
                                     boolean requiresLength,
                                     boolean transferEncoding,
                                     boolean useHttp2) {
+
+        if (marshalled.firstMatchingHeader(CONTENT_LENGTH).isPresent()) {
+            return;
+        }
+
         if (contentLength.isPresent()) {
             marshalled.putHeader(CONTENT_LENGTH, Long.toString(contentLength.get()));
             return;

core/sdk-core/src/test/java/software/amazon/awssdk/core/runtime/transform/AsyncStreamingRequestMarshallerTest.java

@@ -53,7 +53,29 @@ public void setup() {
     }
 
     @Test
-    public void contentLengthHeaderIsSet_IfPresent() {
+    public void contentLengthIsPresent_shouldNotOverride() {
+        long contentLengthOnRequest = 1L;
+        long contengLengthOnRequestBody = 5L;
+        when(requestBody.contentLength()).thenReturn(Optional.of(contengLengthOnRequestBody));
+
+        AsyncStreamingRequestMarshaller marshaller = createMarshaller(true, true, true);
+
+        SdkHttpFullRequest requestWithContentLengthHeader = generateBasicRequest().toBuilder()
+                                                                                  .appendHeader(Header.CONTENT_LENGTH,
+                                                                                   String.valueOf(contentLengthOnRequest))
+                                                                                  .build();
+
+
+        when(delegate.marshall(any())).thenReturn(requestWithContentLengthHeader);
+        SdkHttpFullRequest httpFullRequest = marshaller.marshall(object);
+
+        assertThat(httpFullRequest.firstMatchingHeader(Header.CONTENT_LENGTH)).isPresent();
+        assertContentLengthValue(httpFullRequest, contentLengthOnRequest);
+    }
+
+
+    @Test
+    public void contentLengthOnRequestBody_shouldAddContentLengthHeader() {
         long value = 5L;
         when(requestBody.contentLength()).thenReturn(Optional.of(value));