107155: Allow caching of embedded objects without selflink

Author: Atmire-Kristof

src/app/core/cache/object-cache.reducer.ts

@@ -166,7 +166,7 @@ export function objectCacheReducer(state = initialState, action: ObjectCacheActi
  *    the new state, with the object added, or overwritten.
  */
 function addToObjectCache(state: ObjectCacheState, action: AddToObjectCacheAction): ObjectCacheState {
-  const cacheLink = hasValue(action.payload.objectToCache) ? action.payload.objectToCache._links.self.href : action.payload.alternativeLink;
+  const cacheLink = hasValue(action.payload.objectToCache?._links?.self) ? action.payload.objectToCache._links.self.href : action.payload.alternativeLink;
   const existing = state[cacheLink] || {} as any;
   const newAltLinks = hasValue(action.payload.alternativeLink) ? [action.payload.alternativeLink] : [];
   if (hasValue(cacheLink)) {

src/app/core/data/dspace-rest-response-parsing.service.ts

@@ -110,7 +110,11 @@ export class DspaceRestResponseParsingService implements ResponseParsingService
                 embedAltUrl = new URLCombiner(embedAltUrl, `?size=${match.size}`).toString();
               }
               if (data._embedded[property] == null) {
+                // Embedded object is null, meaning it exists (not undefined), but had an empty response (204) -> cache it as null
                 this.addToObjectCache(null, request, data, embedAltUrl);
+              } else if (!isCacheableObject(data._embedded[property])) {
+                // Embedded object exists, but doesn't contain a self link -> cache it using the alternative link instead
+                this.objectCache.add(data._embedded[property], hasValue(request.responseMsToLive) ? request.responseMsToLive : environment.cache.msToLive.default, request.uuid, embedAltUrl);
               }
               this.process<ObjectDomain>(data._embedded[property], request, embedAltUrl);
             });

src/app/core/index/index.effects.ts

@@ -46,7 +46,7 @@ export class UUIDIndexEffects {
       ofType(ObjectCacheActionTypes.ADD),
       map((action: AddToObjectCacheAction) => {
         const alternativeLink = action.payload.alternativeLink;
-        const selfLink = hasValue(action.payload.objectToCache) ? action.payload.objectToCache._links.self.href : alternativeLink;
+        const selfLink = hasValue(action.payload.objectToCache?._links?.self) ? action.payload.objectToCache._links.self.href : alternativeLink;
         if (hasValue(alternativeLink) && alternativeLink !== selfLink) {
           return new AddToIndexAction(
             IndexName.ALTERNATIVE_OBJECT_LINK,