Refine Content-Range support for Resources

This commit restricts the support of `"Content-Range"` when returning
`Resource` instances from Controllers - now only "HTTP 200 OK" responses
will be considered, as Controllers might want to handle content range
themselves.

Issue: SPR-16921

Author: bclozel

spring-webmvc/src/main/java/org/springframework/web/servlet/mvc/method/annotation/AbstractMessageConverterMethodProcessor.java

@@ -64,6 +64,7 @@
  *
  * @author Arjen Poutsma
  * @author Rossen Stoyanchev
+ * @author Brian Clozel
  * @since 3.1
  */
 public abstract class AbstractMessageConverterMethodProcessor extends AbstractMessageConverterMethodArgumentResolver
@@ -194,7 +195,8 @@ protected <T> void writeWithMessageConverters(@Nullable T value, MethodParameter
 
 		if (isResourceType(value, returnType)) {
 			outputMessage.getHeaders().set(HttpHeaders.ACCEPT_RANGES, "bytes");
-			if (value != null && inputMessage.getHeaders().getFirst(HttpHeaders.RANGE) != null) {
+			if (value != null && inputMessage.getHeaders().getFirst(HttpHeaders.RANGE) != null
+					&& outputMessage.getServletResponse().getStatus() == 200) {
 				Resource resource = (Resource) value;
 				try {
 					List<HttpRange> httpRanges = inputMessage.getHeaders().getRange();
@@ -315,7 +317,7 @@ protected Class<?> getReturnValueType(@Nullable Object value, MethodParameter re
 	}
 
 	/**
-	 * Return whether the returned value or the declared return type extend {@link Resource}.
+	 * Return whether the returned value or the declared return type extends {@link Resource}.
 	 */
 	protected boolean isResourceType(@Nullable Object value, MethodParameter returnType) {
 		Class<?> clazz = getReturnValueType(value, returnType);

spring-webmvc/src/test/java/org/springframework/web/servlet/mvc/method/annotation/HttpEntityMethodProcessorMockTests.java

@@ -568,8 +568,24 @@ public void disableRangeSupportForStreamingResponses() throws Exception {
 		assertThat(servletResponse.getHeader(HttpHeaders.ACCEPT_RANGES), Matchers.isEmptyOrNullString());
 	}
 
+	@Test //SPR-16921
+	public void disableRangeSupportIfContentRangePresent() throws Exception {
+		ResponseEntity<Resource> returnValue = ResponseEntity
+				.status(HttpStatus.PARTIAL_CONTENT)
+				.header(HttpHeaders.RANGE, "bytes=0-5")
+				.body(new ByteArrayResource("Content".getBytes(StandardCharsets.UTF_8)));
+
+		given(resourceRegionMessageConverter.canWrite(any(), eq(null))).willReturn(true);
+		given(resourceRegionMessageConverter.canWrite(any(), eq(APPLICATION_OCTET_STREAM))).willReturn(true);
+
+		processor.handleReturnValue(returnValue, returnTypeResponseEntityResource, mavContainer, webRequest);
+
+		then(resourceRegionMessageConverter).should(never()).write(anyCollection(), any(), any());
+		assertEquals(206, servletResponse.getStatus());
+	}
+
 	@Test  //SPR-14767
-	public void shouldHandleValidatorHeadersInPutResponses() throws Exception {
+	public void shouldHandleValidatorHeadersInputResponses() throws Exception {
 		servletRequest.setMethod("PUT");
 		String etagValue = "\"some-etag\"";
 		ResponseEntity<String> returnValue = ResponseEntity.ok().header(HttpHeaders.ETAG, etagValue).body("body");