DATAREST-1458 - Fixed rendering of compact view to association resour…

…ces.

The usage of text/uri-list as media type was entirely broken and not even advertised in the reference docs anymore. It's now again supported for both to-one and to-many associations via Collections. Maps are rejected as they cannot be rendered as list of URIs correctly. Updated reference documentation accordingly.

Added a custom MapModel implementation of RepresentationModel as apparently using Maps with EntityModel does not unwrap the content properly due to [0].

[0] FasterXML/jackson-databind#171

spring-data-rest-tests/spring-data-rest-tests-core/src/test/java/org/springframework/data/rest/tests/TestMatchers.java

@@ -0,0 +1,81 @@
+/*
+ * Copyright 2019 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.springframework.data.rest.tests;
+
+import java.util.Arrays;
+
+import org.hamcrest.Description;
+import org.hamcrest.Matcher;
+import org.hamcrest.TypeSafeMatcher;
+import org.springframework.util.StringUtils;
+
+/**
+ * {@link Matcher} implementations useful in tests
+ *
+ * @author Oliver Drotbohm
+ */
+public class TestMatchers {
+
+	/**
+	 * Asserts that a {@link String} consists of a given number of lines.
+	 *
+	 * @param number
+	 * @return
+	 */
+	public static Matcher<String> hasNumberOfLines(int number) {
+
+		return new TypeSafeMatcher<String>(String.class) {
+
+			/*
+			 * (non-Javadoc)
+			 * @see org.hamcrest.SelfDescribing#describeTo(org.hamcrest.Description)
+			 */
+			@Override
+			public void describeTo(Description description) {
+				description.appendText("contains " + number + " lines");
+			}
+
+			/*
+			 * (non-Javadoc)
+			 * @see org.hamcrest.TypeSafeMatcher#describeMismatchSafely(java.lang.Object, org.hamcrest.Description)
+			 */
+			@Override
+			protected void describeMismatchSafely(String item, Description mismatchDescription) {
+
+				mismatchDescription.appendText(item) //
+						.appendText(" contains ") //
+						.appendValue(numberOfLines(item)) //
+						.appendText(" lines");
+			}
+
+			/*
+			 * (non-Javadoc)
+			 * @see org.hamcrest.TypeSafeMatcher#matchesSafely(java.lang.Object)
+			 */
+			@Override
+			protected boolean matchesSafely(String item) {
+				return numberOfLines(item) == number;
+			}
+
+			private long numberOfLines(String source) {
+
+				return Arrays.stream(source.split("\n")) //
+						.filter(StringUtils::hasText) //
+						.count();
+			}
+		};
+	}
+}

spring-data-rest-tests/spring-data-rest-tests-mongodb/src/main/java/org/springframework/data/rest/tests/mongodb/User.java

@@ -51,6 +51,8 @@ public static enum Gender {
 	public org.joda.time.LocalDateTime jodaDateTime;
 	public TypeWithPattern pattern;
 	public @DBRef(lazy = true) List<User> colleagues;
+	public @DBRef(lazy = true) User manager;
+	public @DBRef(lazy = true) Map<String, User> map;
 	public Map<String, Nested> colleaguesMap = new HashMap<String, Nested>();
 
 	public static class EmailAddress {

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

@@ -24,13 +24,15 @@
 import java.math.BigDecimal;
 import java.util.Arrays;
 import java.util.Collections;
+import java.util.HashMap;
 
 import org.assertj.core.api.Condition;
 import org.junit.After;
 import org.junit.Before;
 import org.junit.Test;
 import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.data.rest.tests.CommonWebTests;
+import org.springframework.data.rest.tests.TestMatchers;
 import org.springframework.data.rest.webmvc.RestMediaTypes;
 import org.springframework.data.rest.webmvc.support.RepositoryEntityLinks;
 import org.springframework.hateoas.IanaLinkRelations;
@@ -39,6 +41,7 @@
 import org.springframework.http.MediaType;
 import org.springframework.mock.web.MockHttpServletResponse;
 import org.springframework.test.context.ContextConfiguration;
+import org.springframework.test.web.servlet.result.MockMvcResultHandlers;
 import org.springframework.web.util.UriComponentsBuilder;
 
 import com.fasterxml.jackson.annotation.JsonInclude.Include;
@@ -54,6 +57,8 @@
 @ContextConfiguration(classes = MongoDbRepositoryConfig.class)
 public class MongoWebTests extends CommonWebTests {
 
+	private static final MediaType TEXT_URI_LIST = MediaType.parseMediaType("text/uri-list");
+
 	@Autowired ProfileRepository repository;
 	@Autowired UserRepository userRepository;
 	@Autowired RepositoryEntityLinks entityLinks;
@@ -86,15 +91,28 @@ public void populateProfiles() {
 
 		userRepository.save(thomas);
 
+		User mark = new User();
+		mark.firstname = "Mark";
+		mark.lastname = "Paluch";
+		mark.colleagues = Arrays.asList(thomas);
+
+		userRepository.save(mark);
+
 		User oliver = new User();
 		oliver.firstname = "Oliver";
 		oliver.lastname = "Gierke";
 		oliver.address = address;
-		oliver.colleagues = Arrays.asList(thomas);
+		oliver.colleagues = Arrays.asList(thomas, mark);
 		userRepository.save(oliver);
 
-		thomas.colleagues = Arrays.asList(oliver);
+		thomas.manager = oliver;
+		thomas.colleagues = Arrays.asList(oliver, mark);
+		thomas.map = new HashMap<>();
+		thomas.map.put("oliver", oliver);
+		thomas.map.put("mark", mark);
+
 		userRepository.save(thomas);
+
 	}
 
 	@After
@@ -328,8 +346,8 @@ public void exposesETagHeaderForSearchResourceYieldingItemResource() throws Exce
 		Profile profile = repository.findAll().iterator().next();
 
 		mvc.perform(get(link.expand(profile.getId()).getHref()))//
-				.andExpect(header().string("ETag", is("\"0\"")))//
-				.andExpect(header().string("Last-Modified", is(notNullValue())));
+				.andExpect(header().string(ETAG, is("\"0\"")))//
+				.andExpect(header().string(LAST_MODIFIED, is(notNullValue())));
 	}
 
 	@Test // DATAREST-835
@@ -340,7 +358,46 @@ public void doesNotAddETagHeaderForCollectionQueryResource() throws Exception {
 		Profile profile = repository.findAll().iterator().next();
 
 		mvc.perform(get(link.expand(profile.getType()).getHref()))//
-				.andExpect(header().string("ETag", is(nullValue())))//
-				.andExpect(header().string("Last-Modified", is(nullValue())));
+				.andExpect(header().string(ETAG, is(nullValue())))//
+				.andExpect(header().string(LAST_MODIFIED, is(nullValue())));
+	}
+
+	@Test // DATAREST-1458
+	public void accessCollectionAssociationResourceAsUriList() throws Exception {
+
+		Link usersLink = client.discoverUnique("users");
+		Link userLink = assertHasContentLinkWithRel(IanaLinkRelations.SELF, client.request(usersLink));
+		Link colleaguesLink = client.assertHasLinkWithRel("colleagues", client.request(userLink));
+
+		mvc.perform(get(colleaguesLink.expand().getHref()).accept(TEXT_URI_LIST)) //
+				.andExpect(status().isOk()) //
+				.andExpect(header().string(CONTENT_TYPE, is(TEXT_URI_LIST.toString()))) //
+				.andExpect(content().string(TestMatchers.hasNumberOfLines(2)));
+	}
+
+	@Test // DATAREST-1458
+	public void accessAssociationResourceAsUriList() throws Exception {
+
+		Link usersLink = client.discoverUnique("users");
+		Link userLink = assertHasContentLinkWithRel(IanaLinkRelations.SELF, client.request(usersLink));
+		Link managerLink = client.assertHasLinkWithRel("manager", client.request(userLink));
+
+		mvc.perform(get(managerLink.expand().getHref()).accept(TEXT_URI_LIST)) //
+				.andExpect(header().string(CONTENT_TYPE, is(TEXT_URI_LIST.toString()))) //
+				.andExpect(content().string(TestMatchers.hasNumberOfLines(1)));
+	}
+
+	@Test // DATAREST-1458
+	public void accessMapCollectionAssociationResourceAsUriList() throws Exception {
+
+		Link usersLink = client.discoverUnique("users");
+		Link userLink = assertHasContentLinkWithRel(IanaLinkRelations.SELF, client.request(usersLink));
+		Link mapLink = client.assertHasLinkWithRel("map", client.request(userLink));
+
+		mvc.perform(get(mapLink.expand().getHref())) //
+				.andDo(MockMvcResultHandlers.print());
+
+		mvc.perform(get(mapLink.expand().getHref()).accept(TEXT_URI_LIST)) //
+				.andExpect(status().isUnsupportedMediaType());
 	}
 }

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

@@ -15,22 +15,18 @@
  */
 package org.springframework.data.rest.webmvc;
 
-import static org.springframework.data.rest.webmvc.ControllerUtils.*;
+import static java.util.stream.Collectors.*;
 import static org.springframework.data.rest.webmvc.RestMediaTypes.*;
-import static org.springframework.hateoas.server.mvc.WebMvcLinkBuilder.*;
 import static org.springframework.web.bind.annotation.RequestMethod.*;
 
 import lombok.AccessLevel;
 import lombok.RequiredArgsConstructor;
 
 import java.io.Serializable;
-import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.Collection;
 import java.util.Collections;
-import java.util.HashMap;
 import java.util.Iterator;
-import java.util.List;
 import java.util.Map;
 import java.util.Map.Entry;
 import java.util.Optional;
@@ -52,7 +48,6 @@
 import org.springframework.data.rest.core.event.BeforeLinkDeleteEvent;
 import org.springframework.data.rest.core.event.BeforeLinkSaveEvent;
 import org.springframework.data.rest.core.mapping.PropertyAwareResourceMapping;
-import org.springframework.data.rest.core.mapping.ResourceMapping;
 import org.springframework.data.rest.core.mapping.ResourceMetadata;
 import org.springframework.data.rest.webmvc.support.BackendId;
 import org.springframework.data.web.PagedResourcesAssembler;
@@ -61,8 +56,8 @@
 import org.springframework.hateoas.IanaLinkRelations;
 import org.springframework.hateoas.Link;
 import org.springframework.hateoas.LinkRelation;
+import org.springframework.hateoas.Links;
 import org.springframework.hateoas.RepresentationModel;
-import org.springframework.hateoas.server.mvc.WebMvcLinkBuilder;
 import org.springframework.http.HttpHeaders;
 import org.springframework.http.HttpMethod;
 import org.springframework.http.HttpStatus;
@@ -71,7 +66,11 @@
 import org.springframework.web.bind.annotation.ExceptionHandler;
 import org.springframework.web.bind.annotation.PathVariable;
 import org.springframework.web.bind.annotation.RequestBody;
+import org.springframework.web.bind.annotation.RequestHeader;
 import org.springframework.web.bind.annotation.RequestMapping;
+import org.springframework.web.server.UnsupportedMediaTypeStatusException;
+
+import com.fasterxml.jackson.annotation.JsonAnyGetter;
 
 /**
  * @author Jon Brisbin
@@ -126,13 +125,9 @@ public ResponseEntity<RepresentationModel<?>> followPropertyReference(final Root
 
 			} else if (prop.property.isMap()) {
 
-				Map<Object, EntityModel<?>> resources = new HashMap<Object, EntityModel<?>>();
-
-				for (Map.Entry<Object, Object> entry : ((Map<Object, Object>) it).entrySet()) {
-					resources.put(entry.getKey(), assembler.toModel(entry.getValue()));
-				}
-
-				return new EntityModel<Object>(resources);
+				return ((Map<Object, Object>) it).entrySet().stream() //
+						.collect(collectingAndThen(toMap(Map.Entry::getKey, entry -> assembler.toModel(entry.getValue())),
+								MapModel::new));
 
 			} else {
 
@@ -220,54 +215,34 @@ public ResponseEntity<RepresentationModel<?>> followPropertyReference(RootResour
 				doWithReferencedProperty(repoRequest, id, property, handler, HttpMethod.GET));
 	}
 
-	@RequestMapping(value = BASE_MAPPING, method = GET,
-			produces = { SPRING_DATA_COMPACT_JSON_VALUE, TEXT_URI_LIST_VALUE })
+	@RequestMapping(value = BASE_MAPPING, method = GET, produces = TEXT_URI_LIST_VALUE)
 	public ResponseEntity<RepresentationModel<?>> followPropertyReferenceCompact(RootResourceInformation repoRequest,
-			@BackendId Serializable id, @PathVariable String property, PersistentEntityResourceAssembler assembler)
-			throws Exception {
-
-		ResponseEntity<RepresentationModel<?>> response = followPropertyReference(repoRequest, id, property, assembler);
-
-		if (response.getStatusCode() != HttpStatus.OK) {
-			return response;
-		}
-
-		ResourceMetadata repoMapping = repoRequest.getResourceMetadata();
-		PersistentProperty<?> persistentProp = repoRequest.getPersistentEntity().getRequiredPersistentProperty(property);
-		ResourceMapping propertyMapping = repoMapping.getMappingFor(persistentProp);
-
-		RepresentationModel<?> resource = response.getBody();
-
-		List<Link> links = new ArrayList<Link>();
+			@BackendId Serializable id, @PathVariable String property, @RequestHeader HttpHeaders requestHeaders,
+			PersistentEntityResourceAssembler assembler) throws Exception {
 
-		WebMvcLinkBuilder linkBuilder = linkTo(methodOn(RepositoryPropertyReferenceController.class)
-				.followPropertyReference(repoRequest, id, property, assembler));
+		Function<ReferencedProperty, RepresentationModel<?>> handler = prop -> prop.mapValue(it -> {
 
-		if (resource instanceof EntityModel) {
+			if (prop.property.isCollectionLike()) {
 
-			Object content = ((EntityModel<?>) resource).getContent();
-			if (content instanceof Iterable) {
+				Links links = ((Collection<?>) it).stream() //
+						.map(assembler::getExpandedSelfLink) //
+						.collect(Links.collector());
 
-				for (EntityModel<?> res : (Iterable<EntityModel<?>>) content) {
-					links.add(linkBuilder.withRel(propertyMapping.getRel()));
-				}
+				return new RepresentationModel<>(links.toList());
 
-			} else if (content instanceof Map) {
+			} else if (prop.property.isMap()) {
+				throw new UnsupportedMediaTypeStatusException("Cannot produce compact representation of map property!");
+			}
 
-				Map<Object, EntityModel<?>> map = (Map<Object, EntityModel<?>>) content;
+			return new RepresentationModel<>(assembler.getExpandedSelfLink(it));
 
-				for (Entry<Object, EntityModel<?>> entry : map.entrySet()) {
-					Link l = new Link(entry.getValue().getRequiredLink(IanaLinkRelations.SELF).getHref(),
-							entry.getKey().toString());
-					links.add(l);
-				}
-			}
+		}).orElse(new RepresentationModel<>());
 
-		} else {
-			links.add(linkBuilder.withRel(propertyMapping.getRel()));
-		}
+		HttpHeaders headers = new HttpHeaders();
+		headers.setContentType(TEXT_URI_LIST);
 
-		return ControllerUtils.toResponseEntity(HttpStatus.OK, null, new EntityModel<Object>(EMPTY_RESOURCE_LIST, links));
+		return ControllerUtils.toResponseEntity(HttpStatus.OK, headers,
+				doWithReferencedProperty(repoRequest, id, property, handler, HttpMethod.GET));
 	}
 
 	@RequestMapping(value = BASE_MAPPING, method = { PATCH, PUT, POST }, //
@@ -462,6 +437,30 @@ public ResponseEntity<Void> handle(HttpRequestMethodNotSupportedException except
 		return exception.toResponse();
 	}
 
+	/**
+	 * Custom {@link RepresentationModel} to be used with maps as {@link EntityModel} doesn't properly unwrap {@link Map}s
+	 * due to some limitation in Jackson.
+	 *
+	 * @author Oliver Drotbohm
+	 * @see https://github.com/FasterXML/jackson-databind/issues/171
+	 */
+	private static class MapModel extends RepresentationModel<MapModel> {
+
+		private Map<? extends Object, ? extends Object> content;
+
+		public MapModel(Map<? extends Object, ? extends Object> content, Link... links) {
+
+			super(Arrays.asList(links));
+
+			this.content = content;
+		}
+
+		@JsonAnyGetter
+		public Map<? extends Object, ? extends Object> getContent() {
+			return content;
+		}
+	}
+
 	@RequiredArgsConstructor(access = AccessLevel.PRIVATE)
 	static class HttpRequestMethodNotSupportedException extends RuntimeException {