71380: Fix loading/cache issue with dropping objects on page

src/app/+item-page/edit-item-page/item-bitstreams/item-bitstreams.component.ts

@@ -196,9 +196,11 @@ export class ItemBitstreamsComponent extends AbstractItemUpdateComponent impleme
           path: `/_links/bitstreams/${event.toIndex}/href`
         });
         this.bundleService.patch(bundle, [moveOperation]).pipe(take(1)).subscribe((response: RestResponse) => {
+          this.zone.run(() => {
             this.displayNotifications('item.edit.bitstreams.notifications.move', [response]);
             this.requestService.removeByHrefSubstring(bundle.self);
-          this.zone.run(() => event.finish());
+            event.finish();
+          });
         });
       }
     });

src/app/+item-page/edit-item-page/item-bitstreams/item-edit-bitstream-bundle/paginated-drag-and-drop-bitstream-list/paginated-drag-and-drop-bitstream-list.component.spec.ts

@@ -16,6 +16,7 @@ import { ResponsiveTableSizes } from '../../../../../shared/responsive-table-siz
 import { ResponsiveColumnSizes } from '../../../../../shared/responsive-table-sizes/responsive-column-sizes';
 import { createSuccessfulRemoteDataObject$ } from '../../../../../shared/remote-data.utils';
 import { createPaginatedList } from '../../../../../shared/testing/utils.test';
+import { RequestService } from '../../../../../core/data/request.service';
 
 describe('PaginatedDragAndDropBitstreamListComponent', () => {
   let comp: PaginatedDragAndDropBitstreamListComponent;
@@ -23,6 +24,7 @@ describe('PaginatedDragAndDropBitstreamListComponent', () => {
   let objectUpdatesService: ObjectUpdatesService;
   let bundleService: BundleDataService;
   let objectValuesPipe: ObjectValuesPipe;
+  let requestService: RequestService;
 
   const columnSizes = new ResponsiveTableSizes([
     new ResponsiveColumnSizes(2, 2, 3, 4, 4),
@@ -98,18 +100,24 @@ describe('PaginatedDragAndDropBitstreamListComponent', () => {
     );
 
     bundleService = jasmine.createSpyObj('bundleService', {
-      getBitstreams: createSuccessfulRemoteDataObject$(createPaginatedList([bitstream1, bitstream2]))
+      getBitstreams: createSuccessfulRemoteDataObject$(createPaginatedList([bitstream1, bitstream2])),
+      getBitstreamsEndpoint: observableOf('')
     });
 
     objectValuesPipe = new ObjectValuesPipe();
 
+    requestService = jasmine.createSpyObj('requestService', {
+      hasByHrefObservable: observableOf(true)
+    });
+
     TestBed.configureTestingModule({
       imports: [TranslateModule.forRoot()],
       declarations: [PaginatedDragAndDropBitstreamListComponent, VarDirective],
       providers: [
         { provide: ObjectUpdatesService, useValue: objectUpdatesService },
         { provide: BundleDataService, useValue: bundleService },
-        { provide: ObjectValuesPipe, useValue: objectValuesPipe }
+        { provide: ObjectValuesPipe, useValue: objectValuesPipe },
+        { provide: RequestService, useValue: requestService }
       ], schemas: [
         NO_ERRORS_SCHEMA
       ]

src/app/+item-page/edit-item-page/item-bitstreams/item-edit-bitstream-bundle/paginated-drag-and-drop-bitstream-list/paginated-drag-and-drop-bitstream-list.component.ts

@@ -9,6 +9,7 @@ import { PaginatedSearchOptions } from '../../../../../shared/search/paginated-s
 import { ResponsiveTableSizes } from '../../../../../shared/responsive-table-sizes/responsive-table-sizes';
 import { followLink } from '../../../../../shared/utils/follow-link-config.model';
 import { ObjectValuesPipe } from '../../../../../shared/utils/object-values-pipe';
+import { RequestService } from '../../../../../core/data/request.service';
 
 @Component({
   selector: 'ds-paginated-drag-and-drop-bitstream-list',
@@ -35,7 +36,8 @@ export class PaginatedDragAndDropBitstreamListComponent extends AbstractPaginate
   constructor(protected objectUpdatesService: ObjectUpdatesService,
               protected elRef: ElementRef,
               protected objectValuesPipe: ObjectValuesPipe,
-              protected bundleService: BundleDataService) {
+              protected bundleService: BundleDataService,
+              protected requestService: RequestService) {
     super(objectUpdatesService, elRef, objectValuesPipe);
   }
 
@@ -48,12 +50,18 @@ export class PaginatedDragAndDropBitstreamListComponent extends AbstractPaginate
    */
   initializeObjectsRD(): void {
     this.objectsRD$ = this.currentPage$.pipe(
-      switchMap((page: number) => this.bundleService.getBitstreams(
+      switchMap((page: number) => {
+        const paginatedOptions = new PaginatedSearchOptions({pagination: Object.assign({}, this.options, { currentPage: page })});
+        return this.bundleService.getBitstreamsEndpoint(this.bundle.id, paginatedOptions).pipe(
+          switchMap((href) => this.requestService.hasByHrefObservable(href)),
+          switchMap(() => this.bundleService.getBitstreams(
             this.bundle.id,
-        new PaginatedSearchOptions({pagination: Object.assign({}, this.options, { currentPage: page })}),
+            paginatedOptions,
             followLink('format')
           ))
         );
+      })
+    );
   }
 
   /**

src/app/core/data/bundle-data.service.ts

@@ -88,10 +88,12 @@ export class BundleDataService extends DataService<Bundle> {
   /**
    * Get the bitstreams endpoint for a bundle
    * @param bundleId
+   * @param searchOptions
    */
-  getBitstreamsEndpoint(bundleId: string): Observable<string> {
+  getBitstreamsEndpoint(bundleId: string, searchOptions?: PaginatedSearchOptions): Observable<string> {
     return this.getBrowseEndpoint().pipe(
-      switchMap((href: string) => this.halService.getEndpoint(this.bitstreamsEndpoint, `${href}/${bundleId}`))
+      switchMap((href: string) => this.halService.getEndpoint(this.bitstreamsEndpoint, `${href}/${bundleId}`)),
+      map((href) => searchOptions ? searchOptions.toRestUrl(href) : href)
     );
   }
 
@@ -102,9 +104,8 @@ export class BundleDataService extends DataService<Bundle> {
    * @param linksToFollow   The {@link FollowLinkConfig}s for the request
    */
   getBitstreams(bundleId: string, searchOptions?: PaginatedSearchOptions, ...linksToFollow: Array<FollowLinkConfig<Bitstream>>): Observable<RemoteData<PaginatedList<Bitstream>>> {
-    const hrefObs = this.getBitstreamsEndpoint(bundleId).pipe(
-      map((href) => searchOptions ? searchOptions.toRestUrl(href) : href)
-    );
+    const hrefObs = this.getBitstreamsEndpoint(bundleId, searchOptions);
+
     hrefObs.pipe(
       take(1)
     ).subscribe((href) => {

src/app/shared/pagination-drag-and-drop/abstract-paginated-drag-and-drop-list.component.ts

@@ -1,4 +1,4 @@
-import { FieldUpdate, FieldUpdates, Identifiable } from '../../core/data/object-updates/object-updates.reducer';
+import { FieldUpdate, FieldUpdates } from '../../core/data/object-updates/object-updates.reducer';
 import { Observable } from 'rxjs/internal/Observable';
 import { RemoteData } from '../../core/data/remote-data';
 import { PaginatedList } from '../../core/data/paginated-list';
@@ -6,7 +6,7 @@ import { PaginationComponentOptions } from '../pagination/pagination-component-o
 import { BehaviorSubject } from 'rxjs/internal/BehaviorSubject';
 import { ObjectUpdatesService } from '../../core/data/object-updates/object-updates.service';
 import { distinctUntilChanged, map, switchMap, take } from 'rxjs/operators';
-import { hasValue } from '../empty.util';
+import { hasValue, isNotEmpty } from '../empty.util';
 import { paginatedListToArray } from '../../core/shared/operators';
 import { DSpaceObject } from '../../core/shared/dspace-object.model';
 import { CdkDragDrop, moveItemInArray } from '@angular/cdk/drag-drop';
@@ -95,10 +95,19 @@ export abstract class AbstractPaginatedDragAndDropListComponent<T extends DSpace
   /**
    * Whether or not we should display a loading animation
    * This is used to display a loading page when the user drops a bitstream onto a new page. The loading animation
-   * should stop once the bitstream has moved to the new page and the new page's response has loaded
+   * should stop once the bitstream has moved to the new page and the new page's response has loaded and contains the
+   * dropped object on top (see this.stopLoadingWhenFirstIs below)
    */
   loading$: BehaviorSubject<boolean> = new BehaviorSubject<boolean>(false);
 
+  /**
+   * ID of the object the page's first element needs to match in order to stop the loading animation.
+   * This is to ensure the new page is fully loaded containing the latest data from the REST API whenever an object is
+   * dropped on a new page. This allows the component to expect the dropped object to be present on top of the new page,
+   * while displaying a loading animation until this is the case.
+   */
+  stopLoadingWhenFirstIs: string;
+
   /**
    * List of subscriptions
    */
@@ -148,7 +157,15 @@ export abstract class AbstractPaginatedDragAndDropListComponent<T extends DSpace
         distinctUntilChanged(compareArraysUsingFieldUuids())
       ).subscribe((updateValues) => {
         this.customOrder = updateValues.map((fieldUpdate) => fieldUpdate.field.uuid);
-      })
+        // Check if stopLoadingWhenFirstIs contains a value. If it does and it equals the first value in customOrder, stop the loading animation.
+        // This is to ensure the page is updated to contain the new values first, before displaying it.
+        if (hasValue(this.stopLoadingWhenFirstIs) && isNotEmpty(this.customOrder) && this.customOrder[0] === this.stopLoadingWhenFirstIs) {
+          this.stopLoadingWhenFirstIs = undefined;
+          this.loading$.next(false);
+        }
+      }),
+      // Disable the pagination when objects are loading
+      this.loading$.subscribe((loading) => this.options.disabled = loading)
     );
   }
 
@@ -197,6 +214,7 @@ export abstract class AbstractPaginatedDragAndDropListComponent<T extends DSpace
     // Send out a drop event (and navigate to the new page) when the "from" and "to" indexes are different from each other
     if (fromIndex !== toIndex) {
       if (isNewPage) {
+        this.stopLoadingWhenFirstIs = this.customOrder[dragIndex];
         this.customOrder = [];
         this.paginationComponent.doPageChange(redirectPage);
         this.loading$.next(true);
@@ -207,7 +225,6 @@ export abstract class AbstractPaginatedDragAndDropListComponent<T extends DSpace
         finish: () => {
           if (isNewPage) {
             this.currentPage$.next(redirectPage);
-            this.loading$.next(false);
           }
         }
       }));