ResourceHandlerFunction returns EntityResponse

The ResourceHandlerFunction now returns an `EntityResponse<Resource>`
(instead of a `ServerResponse`), so that filters can inspect/change the
returned Resource.

spring-webflux/src/main/java/org/springframework/web/reactive/function/server/ResourceHandlerFunction.java

@@ -56,12 +56,12 @@ class ResourceHandlerFunction implements HandlerFunction<ServerResponse> {
 	public Mono<ServerResponse> handle(ServerRequest request) {
 		switch (request.method()) {
 			case GET:
-				return ServerResponse.ok()
-						.body(BodyInserters.fromResource(this.resource));
+				return EntityResponse.fromObject(this.resource).build()
+						.map(response -> response);
 			case HEAD:
 				Resource headResource = new HeadMethodResource(this.resource);
-				return ServerResponse.ok()
-						.body(BodyInserters.fromResource(headResource));
+				return EntityResponse.fromObject(headResource).build()
+						.map(response -> response);
 			case OPTIONS:
 				return ServerResponse.ok()
 						.allow(SUPPORTED_METHODS)

spring-webflux/src/test/java/org/springframework/web/reactive/function/server/ResourceHandlerFunctionTests.java

@@ -57,13 +57,9 @@ public class ResourceHandlerFunctionTests {
 
 		Mono<Void> result = responseMono.flatMap(response -> {
 					assertEquals(HttpStatus.OK, response.statusCode());
-					/*
-					TODO: enable when ServerEntityResponse is reintroduced
-					StepVerifier.create(response.body())
-							.expectNext(this.resource)
-							.expectComplete()
-							.verify();
-					*/
+					assertTrue(response instanceof EntityResponse);
+					EntityResponse<Resource> entityResponse = (EntityResponse<Resource>) response;
+					assertEquals(this.resource, entityResponse.entity());
 					return response.writeTo(exchange, HandlerStrategies.withDefaults());
 				});
 
@@ -92,11 +88,14 @@ public class ResourceHandlerFunctionTests {
 
 		ServerRequest request = new DefaultServerRequest(exchange, HandlerStrategies.withDefaults());
 
-		Mono<ServerResponse> response = this.handlerFunction.handle(request);
+		Mono<ServerResponse> responseMono = this.handlerFunction.handle(request);
 
-		Mono<Void> result = response.flatMap(res -> {
-			assertEquals(HttpStatus.OK, res.statusCode());
-			return res.writeTo(exchange, HandlerStrategies.withDefaults());
+		Mono<Void> result = responseMono.flatMap(response -> {
+			assertEquals(HttpStatus.OK, response.statusCode());
+			assertTrue(response instanceof EntityResponse);
+			EntityResponse<Resource> entityResponse = (EntityResponse<Resource>) response;
+			assertEquals(this.resource.getFilename(), entityResponse.entity().getFilename());
+			return response.writeTo(exchange, HandlerStrategies.withDefaults());
 		});
 
 		StepVerifier.create(result).expectComplete().verify();
@@ -118,12 +117,6 @@ public class ResourceHandlerFunctionTests {
 			assertEquals(HttpStatus.OK, response.statusCode());
 			assertEquals(EnumSet.of(HttpMethod.GET, HttpMethod.HEAD, HttpMethod.OPTIONS),
 					response.headers().getAllow());
-			/*
-			TODO: enable when ServerEntityResponse is reintroduced
-			StepVerifier.create(response.body())
-					.expectComplete()
-					.verify();
-			*/
 			return response.writeTo(exchange, HandlerStrategies.withDefaults());
 		});