Add previously processed links

dspace-server-webapp/src/main/java/org/dspace/app/rest/converter/ConverterService.java

@@ -32,6 +32,7 @@ import org.springframework.core.type.filter.AssignableTypeFilter;
 import org.springframework.data.domain.Page;
 import org.springframework.data.domain.PageImpl;
 import org.springframework.data.domain.Pageable;
+import org.springframework.hateoas.Link;
 import org.springframework.hateoas.Resource;
 import org.springframework.stereotype.Component;
 import org.springframework.stereotype.Service;
@@ -155,9 +156,12 @@ public class ConverterService {
      * @throws ClassCastException if the resource type is not compatible with the inferred return type.
      */
     public <T extends HALResource> T toResource(RestModel restObject) {
+        return toResource(restObject, new Link[] {});
+    }
+    public <T extends HALResource> T toResource(RestModel restObject, Link... oldLinks) {
         T halResource = getResource(restObject);
         if (restObject instanceof RestAddressableModel) {
-            utils.embedOrLinkClassLevelRels(halResource);
+            utils.embedOrLinkClassLevelRels(halResource, oldLinks);
             halLinkService.addLinks(halResource);
             Projection projection = ((RestAddressableModel) restObject).getProjection();
             return projection.transformResource(halResource);

dspace-server-webapp/src/main/java/org/dspace/app/rest/projection/AbstractProjection.java

@@ -11,6 +11,7 @@ import org.dspace.app.rest.model.LinkRest;
 import org.dspace.app.rest.model.RestAddressableModel;
 import org.dspace.app.rest.model.RestModel;
 import org.dspace.app.rest.model.hateoas.HALResource;
+import org.springframework.hateoas.Link;
 
 /**
  * Abstract base class for projections.
@@ -35,7 +36,7 @@ public abstract class AbstractProjection implements Projection {
     }
 
     @Override
-    public boolean allowEmbedding(HALResource<? extends RestAddressableModel> halResource, LinkRest linkRest) {
+    public boolean allowEmbedding(HALResource<? extends RestAddressableModel> halResource, LinkRest linkRest, Link... oldLinks) {
         return false;
     }
 

dspace-server-webapp/src/main/java/org/dspace/app/rest/projection/CompositeProjection.java

@@ -13,6 +13,7 @@ import org.dspace.app.rest.model.LinkRest;
 import org.dspace.app.rest.model.RestAddressableModel;
 import org.dspace.app.rest.model.RestModel;
 import org.dspace.app.rest.model.hateoas.HALResource;
+import org.springframework.hateoas.Link;
 
 /**
  * A projection that combines the behavior of multiple projections.
@@ -61,9 +62,9 @@ public class CompositeProjection implements Projection {
     }
 
     @Override
-    public boolean allowEmbedding(HALResource<? extends RestAddressableModel> halResource, LinkRest linkRest) {
+    public boolean allowEmbedding(HALResource<? extends RestAddressableModel> halResource, LinkRest linkRest, Link... oldLinks) {
         for (Projection projection : projections) {
-            if (projection.allowEmbedding(halResource, linkRest)) {
+            if (projection.allowEmbedding(halResource, linkRest, oldLinks)) {
                 return true;
             }
         }

dspace-server-webapp/src/main/java/org/dspace/app/rest/projection/EmbedRelsProjection.java

@@ -12,6 +12,7 @@ import java.util.Set;
 import org.dspace.app.rest.model.LinkRest;
 import org.dspace.app.rest.model.RestAddressableModel;
 import org.dspace.app.rest.model.hateoas.HALResource;
+import org.springframework.hateoas.Link;
 
 /**
  * Projection that allows a given set of rels to be embedded.
@@ -32,9 +33,22 @@ public class EmbedRelsProjection extends AbstractProjection {
     }
 
     @Override
-    public boolean allowEmbedding(HALResource<? extends RestAddressableModel> halResource, LinkRest linkRest) {
+    public boolean allowEmbedding(HALResource<? extends RestAddressableModel> halResource, LinkRest linkRest, Link... oldLinks) {
-        if (halResource.getContent().getEmbedLevel() == 0)
+        if (halResource.getContent().getEmbedLevel() == 0 && embedRels.contains(linkRest.name()))
-            return embedRels.contains(linkRest.name());
+            return true;
+        StringBuilder fullName = new StringBuilder();
+        for (Link oldLink : oldLinks) {
+            fullName.append(oldLink.getRel()).append("/");
+        }
+        fullName.append(linkRest.name());
+        if (embedRels.contains(fullName.toString())) {
+            return true;
+        }
+        fullName.append("/");
+        for (String embedRel : embedRels) {
+            if (embedRel.startsWith(fullName.toString()))
+                return true;
+        }
         return false;
     }
 }

dspace-server-webapp/src/main/java/org/dspace/app/rest/projection/FullProjection.java

@@ -9,6 +9,7 @@ package org.dspace.app.rest.projection;
 
 import org.dspace.app.rest.model.LinkRest;
 import org.dspace.app.rest.model.hateoas.HALResource;
+import org.springframework.hateoas.Link;
 import org.springframework.stereotype.Component;
 
 /**
@@ -24,7 +25,7 @@ public class FullProjection extends AbstractProjection {
     }
 
     @Override
-    public boolean allowEmbedding(HALResource halResource, LinkRest linkRest) {
+    public boolean allowEmbedding(HALResource halResource, LinkRest linkRest, Link... oldLinks) {
         return true;
     }
 

dspace-server-webapp/src/main/java/org/dspace/app/rest/projection/Projection.java

@@ -15,6 +15,7 @@ import org.dspace.app.rest.model.RestModel;
 import org.dspace.app.rest.model.hateoas.HALResource;
 import org.dspace.app.rest.repository.DSpaceRestRepository;
 import org.dspace.app.rest.utils.Utils;
+import org.springframework.hateoas.Link;
 import org.springframework.stereotype.Component;
 import org.springframework.web.bind.annotation.RestController;
 
@@ -118,7 +119,7 @@ public interface Projection {
      * @param linkRest the LinkRest annotation through which the related resource was discovered on the rest object.
      * @return true if allowed, false otherwise.
      */
-    boolean allowEmbedding(HALResource<? extends RestAddressableModel> halResource, LinkRest linkRest);
+    boolean allowEmbedding(HALResource<? extends RestAddressableModel> halResource, LinkRest linkRest, Link... oldLinks);
 
     /**
      * Tells whether this projection permits the linking of a particular linkable subresource.

dspace-server-webapp/src/main/java/org/dspace/app/rest/utils/Utils.java

@@ -516,13 +516,14 @@ public class Utils {
      * Adds embeds or links for all class-level LinkRel annotations for which embeds or links are allowed.
      *
      * @param halResource the resource.
+     * @param oldLinks    previously traversed links
      */
-    public void embedOrLinkClassLevelRels(HALResource<RestAddressableModel> halResource) {
+    public void embedOrLinkClassLevelRels(HALResource<RestAddressableModel> halResource, Link... oldLinks) {
         Projection projection = halResource.getContent().getProjection();
         getLinkRests(halResource.getContent().getClass()).stream().forEach((linkRest) -> {
             Link link = linkToSubResource(halResource.getContent(), linkRest.name());
-            if (projection.allowEmbedding(halResource, linkRest)) {
+            if (projection.allowEmbedding(halResource, linkRest, oldLinks)) {
-                embedRelFromRepository(halResource, linkRest.name(), link, linkRest);
+                embedRelFromRepository(halResource, linkRest.name(), link, linkRest, oldLinks);
                 halResource.add(link); // unconditionally link if embedding was allowed
             } else if (projection.allowLinking(halResource, linkRest)) {
                 halResource.add(link);
@@ -561,6 +562,10 @@ public class Utils {
      */
     void embedRelFromRepository(HALResource<? extends RestAddressableModel> resource,
                                         String rel, Link link, LinkRest linkRest) {
+        embedRelFromRepository(resource, rel, link, linkRest, new Link[] {});
+    }
+    void embedRelFromRepository(HALResource<? extends RestAddressableModel> resource,
+                                        String rel, Link link, LinkRest linkRest, Link... oldLinks) {
         if (resource.getContent().getEmbedLevel() == EMBED_MAX_LEVELS) {
             return;
         }
@@ -572,7 +577,7 @@ public class Utils {
             Object contentId = getContentIdForLinkMethod(resource.getContent(), method);
             try {
                 Object linkedObject = method.invoke(linkRepository, null, contentId, null, projection);
-                resource.embedResource(rel, wrapForEmbedding(resource, linkedObject, link));
+                resource.embedResource(rel, wrapForEmbedding(resource, linkedObject, link, oldLinks));
             } catch (InvocationTargetException e) {
                 if (e.getTargetException() instanceof RuntimeException) {
                     throw (RuntimeException) e.getTargetException();
@@ -677,17 +682,23 @@ public class Utils {
      */
     private Object wrapForEmbedding(HALResource<? extends RestAddressableModel> resource,
                                     Object linkedObject, Link link) {
+        return wrapForEmbedding(resource, linkedObject, link, new Link[] {});
+    }
+    private Object wrapForEmbedding(HALResource<? extends RestAddressableModel> resource,
+                                    Object linkedObject, Link link, Link... oldLinks) {
         int childEmbedLevel = resource.getContent().getEmbedLevel() + 1;
+        Link[] newList = Arrays.copyOf(oldLinks, oldLinks.length+1);
+        newList[oldLinks.length] = link;
         if (linkedObject instanceof RestAddressableModel) {
             RestAddressableModel restObject = (RestAddressableModel) linkedObject;
             restObject.setEmbedLevel(childEmbedLevel);
-            return converter.toResource(restObject);
+            return converter.toResource(restObject, newList);
         } else if (linkedObject instanceof Page) {
             // The first page has already been constructed by a link repository and we only need to wrap it
             Page<RestAddressableModel> page = (Page<RestAddressableModel>) linkedObject;
             return new EmbeddedPage(link.getHref(), page.map((restObject) -> {
                 restObject.setEmbedLevel(childEmbedLevel);
-                return converter.toResource(restObject);
+                return converter.toResource(restObject, newList);
             }), null, link.getRel());
         } else if (linkedObject instanceof List) {
             // The full list has been retrieved and we need to provide the first page for embedding
@@ -699,7 +710,7 @@ public class Utils {
                 return new EmbeddedPage(link.getHref(),
                         page.map((restObject) -> {
                             restObject.setEmbedLevel(childEmbedLevel);
-                            return converter.toResource(restObject);
+                            return converter.toResource(restObject, newList);
                         }),
                         list, link.getRel());
             } else {

dspace-server-webapp/src/test/java/org/dspace/app/rest/projection/MockProjection.java

@@ -87,7 +87,7 @@ public class MockProjection implements Projection {
         return halResource;
     }
 
-    public boolean allowEmbedding(HALResource halResource, LinkRest linkRest) {
+    public boolean allowEmbedding(HALResource halResource, LinkRest linkRest, Link... oldLinks) {
         return true;
     }