DATAREST-506 - NotModified responses now return headers, too.

Responses for item resources that result in 304 Not Modifier now also return the headers they'd return if a 200 Ok would've been returned.

spring-data-rest-webmvc/src/main/java/org/springframework/data/rest/webmvc/AbstractRepositoryRestController.java

@@ -24,6 +24,7 @@
 import org.springframework.data.auditing.AuditableBeanWrapper;
 import org.springframework.data.auditing.AuditableBeanWrapperFactory;
 import org.springframework.data.domain.Page;
+import org.springframework.data.mapping.PersistentEntity;
 import org.springframework.data.rest.core.mapping.ResourceMetadata;
 import org.springframework.data.rest.webmvc.support.ETag;
 import org.springframework.data.web.PagedResourcesAssembler;
@@ -132,18 +133,24 @@ protected Resources<Resource<Object>> entitiesToResources(Iterable<Object> entit
 	 * @return
 	 */
 	protected HttpHeaders prepareHeaders(PersistentEntityResource resource) {
+		return resource == null ? new HttpHeaders() : prepareHeaders(resource.getPersistentEntity(), resource.getContent());
+	}
 
-		HttpHeaders headers = new HttpHeaders();
-
-		if (resource == null) {
-			return headers;
-		}
+	/**
+	 * Retruns the default headers to be returned for the given {@link PersistentEntity} and value. Will set {@link ETag}
+	 * and {@code Last-Modified} headers if applicable.
+	 * 
+	 * @param entity must not be {@literal null}.
+	 * @param value must not be {@literal null}.
+	 * @return
+	 */
+	protected HttpHeaders prepareHeaders(PersistentEntity<?, ?> entity, Object value) {
 
 		// Add ETag
-		headers = ETag.from(resource).addTo(headers);
+		HttpHeaders headers = ETag.from(entity, value).addTo(new HttpHeaders());
 
 		// Add Last-Modified
-		AuditableBeanWrapper wrapper = getAuditableBeanWrapper(resource.getContent());
+		AuditableBeanWrapper wrapper = getAuditableBeanWrapper(value);
 
 		if (wrapper == null) {
 			return headers;

spring-data-rest-webmvc/src/main/java/org/springframework/data/rest/webmvc/RepositoryEntityController.java

@@ -31,6 +31,7 @@
 import org.springframework.data.auditing.AuditableBeanWrapper;
 import org.springframework.data.auditing.AuditableBeanWrapperFactory;
 import org.springframework.data.domain.Sort;
+import org.springframework.data.mapping.PersistentEntity;
 import org.springframework.data.mapping.PersistentPropertyAccessor;
 import org.springframework.data.mapping.model.ConvertingPropertyAccessor;
 import org.springframework.data.repository.support.Repositories;
@@ -319,9 +320,10 @@ public ResponseEntity<Resource<?>> getItemResource(RootResourceInformation resou
 
 		List<String> ifNoneMatch = headers.getIfNoneMatch();
 		ETag eTag = ifNoneMatch.isEmpty() ? ETag.NO_ETAG : ETag.from(ifNoneMatch.get(0));
+		PersistentEntity<?, ?> entity = resourceInformation.getPersistentEntity();
 
-		if (eTag.matches(resourceInformation.getPersistentEntity(), domainObj)) {
-			return new ResponseEntity<Resource<?>>(HttpStatus.NOT_MODIFIED);
+		if (eTag.matches(entity, domainObj)) {
+			return new ResponseEntity<Resource<?>>(prepareHeaders(entity, domainObj), HttpStatus.NOT_MODIFIED);
 		}
 
 		// Check last modification for If-Modfied-Since
@@ -332,7 +334,7 @@ public ResponseEntity<Resource<?>> getItemResource(RootResourceInformation resou
 			long current = wrapper.getLastModifiedDate().getTimeInMillis() / 1000 * 1000;
 
 			if (current <= headers.getIfModifiedSince()) {
-				return new ResponseEntity<Resource<?>>(HttpStatus.NOT_MODIFIED);
+				return new ResponseEntity<Resource<?>>(prepareHeaders(entity, domainObj), HttpStatus.NOT_MODIFIED);
 			}
 		}
 

spring-data-rest-webmvc/src/main/java/org/springframework/data/rest/webmvc/support/ETag.java

@@ -65,6 +65,17 @@ public static ETag from(PersistentEntityResource resource) {
 		return resource == null ? NO_ETAG : from(resource.getPersistentEntity(), resource.getContent());
 	}
 
+	/**
+	 * Creates a new {@link ETag} from the given {@link PersistentEntity} and target bean.
+	 * 
+	 * @param entity must not be {@literal null}.
+	 * @param bean must not be {@literal null}.
+	 * @return
+	 */
+	public static ETag from(PersistentEntity<?, ?> entity, Object bean) {
+		return from(getVersionInformation(entity, bean));
+	}
+
 	/**
 	 * Verifies the ETag to be created for the given target bean with the current one and raises a
 	 * {@link ETagDoesntMatchException} in case they don't match.
@@ -160,17 +171,6 @@ public int hashCode() {
 		return value.hashCode();
 	}
 
-	/**
-	 * Creates a new {@link ETag} from the given {@link PersistentEntity} and target bean.
-	 * 
-	 * @param entity
-	 * @param bean
-	 * @return
-	 */
-	private static ETag from(PersistentEntity<?, ?> entity, Object bean) {
-		return from(getVersionInformation(entity, bean));
-	}
-
 	/**
 	 * Returns the quoted version property of a domain object, returns null if it doesn't contains the property
 	 *

spring-data-rest-webmvc/src/test/java/org/springframework/data/rest/webmvc/mongodb/MongoWebTests.java

@@ -17,6 +17,7 @@
 
 import static org.hamcrest.Matchers.*;
 import static org.junit.Assert.*;
+import static org.springframework.http.HttpHeaders.*;
 import static org.springframework.test.web.servlet.request.MockMvcRequestBuilders.*;
 import static org.springframework.test.web.servlet.result.MockMvcResultMatchers.*;
 
@@ -292,10 +293,12 @@ public void supportsConditionalGetsOnItemResource() throws Exception {
 
 		Link receiptLink = client.getDiscoverer(response).findLinkWithRel("self", response.getContentAsString());
 
-		mvc.perform(get(receiptLink.getHref()).header("If-Modified-Since", response.getHeader("Last-Modified"))).//
-				andExpect(status().isNotModified());
+		mvc.perform(get(receiptLink.getHref()).header(IF_MODIFIED_SINCE, response.getHeader(LAST_MODIFIED))).//
+				andExpect(status().isNotModified()).//
+				andExpect(header().string(ETAG, is(notNullValue())));
 
-		mvc.perform(get(receiptLink.getHref()).header("If-None-Match", response.getHeader("ETag"))).//
-				andExpect(status().isNotModified());
+		mvc.perform(get(receiptLink.getHref()).header(IF_NONE_MATCH, response.getHeader(ETAG))).//
+				andExpect(status().isNotModified()).//
+				andExpect(header().string(ETAG, is(notNullValue())));
 	}
 }