Change hidden file structure to hiddenLink

src/main/java/de/tum/cit/aet/artemis/lecture/domain/Attachment.java

@@ -61,6 +61,9 @@ public class Attachment extends DomainObject implements Serializable {
     @JoinColumn(name = "attachment_unit_id")
     private AttachmentUnit attachmentUnit;
 
+    @Column(name = "hidden_link")
+    private String hiddenLink;
+
     // jhipster-needle-entity-add-field - JHipster will add fields here, do not remove
 
     public String getName() {
@@ -135,6 +138,14 @@ public void setAttachmentUnit(AttachmentUnit attachmentUnit) {
         this.attachmentUnit = attachmentUnit;
     }
 
+    public String getHiddenLink() {
+        return hiddenLink;
+    }
+
+    public void setHiddenLink(String hiddenLink) {
+        this.hiddenLink = hiddenLink;
+    }
+
     public Boolean isVisibleToStudents() {
         if (releaseDate == null) {  // no release date means the attachment is visible to students
             return Boolean.TRUE;

src/main/java/de/tum/cit/aet/artemis/lecture/web/AttachmentResource.java

@@ -101,23 +101,24 @@ public ResponseEntity<Attachment> createAttachment(@RequestPart Attachment attac
     }
 
     /**
-     * PUT /attachments/:id : Updates an existing attachment.
+     * PUT /attachments/:id : Updates an existing attachment, optionally handling both public and hidden files.
      *
      * @param attachmentId     the id of the attachment to save
      * @param attachment       the attachment to update
      * @param file             the file to save if the file got changed (optional)
-     * @param notificationText text that will be sent to student group
+     * @param hiddenFile       the file to add as hidden version of the attachment (optional)
+     * @param notificationText text that will be sent to the student group (optional)
      * @return the ResponseEntity with status 200 (OK) and with body the updated attachment, or with status 400 (Bad Request) if the attachment is not valid, or with status 500
      *         (Internal Server Error) if the attachment couldn't be updated
      */
     @PutMapping(value = "attachments/{attachmentId}", consumes = MediaType.MULTIPART_FORM_DATA_VALUE)
     @EnforceAtLeastEditor
     public ResponseEntity<Attachment> updateAttachment(@PathVariable Long attachmentId, @RequestPart Attachment attachment, @RequestPart(required = false) MultipartFile file,
-            @RequestParam(value = "notificationText", required = false) String notificationText) {
+            @RequestPart(required = false) MultipartFile hiddenFile, @RequestParam(value = "notificationText", required = false) String notificationText) {
         log.debug("REST request to update Attachment : {}", attachment);
         attachment.setId(attachmentId);
 
-        // Make sure that the original references are preserved.
+        // Make sure that the original references are preserved
         Attachment originalAttachment = attachmentRepository.findByIdOrElseThrow(attachment.getId());
         attachment.setAttachmentUnit(originalAttachment.getAttachmentUnit());
 
@@ -131,6 +132,20 @@ public ResponseEntity<Attachment> updateAttachment(@PathVariable Long attachment
             this.fileService.evictCacheForPath(FilePathService.actualPathForPublicPathOrThrow(oldPath));
         }
 
+        if (hiddenFile != null) {
+            // Update hidden file logic
+            Path basePath = FilePathService.getAttachmentUnitFilePath().resolve(originalAttachment.getAttachmentUnit().getId().toString());
+            Path savePath = fileService.saveFile(hiddenFile, basePath, true);
+            attachment.setHiddenLink(FilePathService.publicPathForActualPath(savePath, originalAttachment.getAttachmentUnit().getId()).toString() + "v2");
+
+            // Delete the old hidden file
+            if (originalAttachment.getHiddenLink() != null) {
+                URI oldHiddenPath = URI.create(originalAttachment.getHiddenLink());
+                fileService.schedulePathForDeletion(FilePathService.actualPathForPublicPathOrThrow(oldHiddenPath), 0);
+                fileService.evictCacheForPath(FilePathService.actualPathForPublicPathOrThrow(oldHiddenPath));
+            }
+        }
+
         Attachment result = attachmentRepository.save(attachment);
         if (notificationText != null) {
             groupNotificationService.notifyStudentGroupAboutAttachmentChange(result, notificationText);

src/main/resources/config/liquibase/changelog/20241117234100_changelog.xml → src/main/resources/config/liquibase/changelog/20241129170228_changelog.xml

@@ -2,9 +2,13 @@
 <databaseChangeLog xmlns="http://www.liquibase.org/xml/ns/dbchangelog"
                    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
                    xsi:schemaLocation="http://www.liquibase.org/xml/ns/dbchangelog https://www.liquibase.org/xml/ns/dbchangelog/dbchangelog-latest.xsd">
-    <changeSet id="20241117234100" author="ece.eren">
+    <changeSet id="20241129170228" author="ece.eren">
         <addColumn tableName="slide">
             <column name="hidden" type="datetime(3)"/>
         </addColumn>
+
+        <addColumn tableName="attachment">
+            <column name="hidden_link" type="varchar(255)" />
+        </addColumn>
     </changeSet>
 </databaseChangeLog>

src/main/resources/config/liquibase/master.xml

@@ -33,7 +33,7 @@
     <include file="classpath:config/liquibase/changelog/20241010101010_changelog.xml" relativeToChangelogFile="false"/>
     <include file="classpath:config/liquibase/changelog/20241018053210_changelog.xml" relativeToChangelogFile="false"/>
     <include file="classpath:config/liquibase/changelog/20241023456789_changelog.xml" relativeToChangelogFile="false"/>
-    <include file="classpath:config/liquibase/changelog/20241117234100_changelog.xml" relativeToChangelogFile="false"/>
+    <include file="classpath:config/liquibase/changelog/20241129170228_changelog.xml" relativeToChangelogFile="false"/>
 
     <!-- NOTE: please use the format "YYYYMMDDhhmmss_changelog.xml", i.e. year month day hour minutes seconds and not something else! -->
     <!-- we should also stay in a chronological order! -->

src/main/webapp/app/entities/attachment.model.ts

@@ -20,6 +20,7 @@ export class Attachment implements BaseEntity {
     lecture?: Lecture;
     exercise?: Exercise;
     attachmentUnit?: AttachmentUnit;
+    hiddenLink?: string;
 
     constructor() {}
 }

src/main/webapp/app/lecture/attachment.service.ts

@@ -45,14 +45,15 @@ export class AttachmentService {
      * @param attachmentId the id of the attachment to update
      * @param attachment the attachment object holding the updated values
      * @param file the file to save as an attachment if it was changed (optional)
+     * @param hiddenFile the file to add as hidden version of the attachment (optional)
      * @param req optional request parameters
      */
-    update(attachmentId: number, attachment: Attachment, file?: File, req?: any): Observable<EntityResponseType> {
+    update(attachmentId: number, attachment: Attachment, file?: File, hiddenFile?: File, req?: any): Observable<EntityResponseType> {
         const options = createRequestOption(req);
         const copy = this.convertAttachmentDatesFromClient(attachment);
 
         return this.http
-            .put<Attachment>(this.resourceUrl + '/' + attachmentId, this.createFormData(copy, file), { params: options, observe: 'response' })
+            .put<Attachment>(this.resourceUrl + '/' + attachmentId, this.createFormData(copy, file, hiddenFile), { params: options, observe: 'response' })
             .pipe(map((res: EntityResponseType) => this.convertAttachmentResponseDatesFromServer(res)));
     }
 
@@ -128,12 +129,15 @@ export class AttachmentService {
         return res;
     }
 
-    private createFormData(attachment: Attachment, file?: File) {
+    private createFormData(attachment: Attachment, file?: File, hiddenFile?: File) {
         const formData = new FormData();
         formData.append('attachment', objectToJsonBlob(attachment));
         if (file) {
             formData.append('file', file);
         }
+        if (hiddenFile) {
+            formData.append('hiddenFile', hiddenFile);
+        }
         return formData;
     }
 

src/main/webapp/app/lecture/pdf-preview/pdf-preview.component.html

@@ -70,7 +70,12 @@ <h4>
                 </a>
             </div>
             <div>
-                <button type="submit" (click)="updateAttachmentWithFile()" class="btn btn-primary" [disabled]="isPdfLoading() || totalPages() === 0 || !isFileChanged()">
+                <button
+                    type="submit"
+                    (click)="updateAttachmentWithFile()"
+                    class="btn btn-primary"
+                    [disabled]="(isPdfLoading() || totalPages() === 0 || !isFileChanged()) && !hiddenPagesChanged()"
+                >
                     <fa-icon [icon]="faSave" [ngbTooltip]="'entity.action.save' | artemisTranslate"></fa-icon>
                     <span jhiTranslate="entity.action.save"></span>
                 </button>

src/main/webapp/app/lecture/pdf-preview/pdf-preview.component.ts

@@ -1,4 +1,4 @@
-import { Component, ElementRef, OnChanges, OnDestroy, OnInit, SimpleChanges, computed, inject, signal, viewChild } from '@angular/core';
+import { Component, ElementRef, OnDestroy, OnInit, computed, effect, inject, signal, viewChild } from '@angular/core';
 import { ActivatedRoute, Router } from '@angular/router';
 import { AttachmentService } from 'app/lecture/attachment.service';
 import { Attachment } from 'app/entities/attachment.model';
@@ -17,6 +17,7 @@ import { MAX_FILE_SIZE } from 'app/shared/constants/input.constants';
 import { PdfPreviewThumbnailGridComponent } from 'app/lecture/pdf-preview/pdf-preview-thumbnail-grid/pdf-preview-thumbnail-grid.component';
 import { LectureUnitService } from 'app/lecture/lecture-unit/lecture-unit-management/lectureUnit.service';
 import { PDFDocument } from 'pdf-lib';
+import cloneDeep from 'lodash-es/cloneDeep';
 
 @Component({
     selector: 'jhi-pdf-preview-component',
@@ -25,7 +26,7 @@ import { PDFDocument } from 'pdf-lib';
     standalone: true,
     imports: [ArtemisSharedModule, PdfPreviewThumbnailGridComponent],
 })
-export class PdfPreviewComponent implements OnInit, OnDestroy, OnChanges {
+export class PdfPreviewComponent implements OnInit, OnDestroy {
     fileInput = viewChild.required<ElementRef<HTMLInputElement>>('fileInput');
 
     attachmentSub: Subscription;
@@ -44,6 +45,7 @@ export class PdfPreviewComponent implements OnInit, OnDestroy, OnChanges {
     isFileChanged = signal<boolean>(false);
     selectedPages = signal<Set<number>>(new Set());
     allPagesSelected = computed(() => this.selectedPages().size === this.totalPages());
+    initialHiddenPages = signal<Set<number>>(new Set());
     hiddenPages = signal<Set<number>>(new Set());
 
     // Injected services
@@ -80,6 +82,7 @@ export class PdfPreviewComponent implements OnInit, OnDestroy, OnChanges {
                 this.attachmentUnit.set(data.attachmentUnit);
                 this.attachmentUnitService.getHiddenSlides(this.attachmentUnit()!.lecture!.id!, this.attachmentUnit()!.id!).subscribe({
                     next: (hiddenPages: number[]) => {
+                        this.initialHiddenPages.set(new Set(hiddenPages));
                         this.hiddenPages.set(new Set(hiddenPages));
                     },
                     error: (error: HttpErrorResponse) => onError(this.alertService, error),
@@ -100,18 +103,36 @@ export class PdfPreviewComponent implements OnInit, OnDestroy, OnChanges {
         this.attachmentUnitSub?.unsubscribe();
     }
 
-    ngOnChanges(changes: SimpleChanges): void {
-        if (changes['hiddenPages']) {
-            this.isFileChanged.set(true);
-        }
+    constructor() {
+        effect(
+            () => {
+                this.hiddenPagesChanged();
+            },
+            { allowSignalWrites: true },
+        );
     }
+
     /**
      * Triggers the file input to select files.
      */
     triggerFileInput(): void {
         this.fileInput().nativeElement.click();
     }
 
+    /**
+     * Checks if there has been any change between the current set of hidden pages and the new set of hidden pages.
+     *
+     * @returns Returns true if the sets differ in size or if any element in `newHiddenPages` is not found in `hiddenPages`, otherwise false.
+     */
+    hiddenPagesChanged() {
+        if (this.initialHiddenPages()!.size !== this.hiddenPages()!.size) return true;
+
+        for (const elem of this.initialHiddenPages()!) {
+            if (!this.hiddenPages()!.has(elem)) return true;
+        }
+        return false;
+    }
+
     /**
      * Retrieves an array of hidden page numbers from elements with IDs starting with "show-button-".
      *
@@ -121,15 +142,15 @@ export class PdfPreviewComponent implements OnInit, OnDestroy, OnChanges {
         return Array.from(document.querySelectorAll('.hide-show-btn.btn-success'))
             .map((el) => {
                 const match = el.id.match(/hide-show-button-(\d+)/);
-                return match ? match[1] : null;
+                return match ? parseInt(match[1], 10) : null;
             })
             .filter((id) => id !== null);
     }
 
     /**
      * Updates the existing attachment file or creates a new hidden version of the attachment.
      */
-    updateAttachmentWithFile(): void {
+    async updateAttachmentWithFile(): Promise<void> {
         const pdfFile = new File([this.currentPdfBlob()!], 'updatedAttachment.pdf', { type: 'application/pdf' });
 
         if (pdfFile.size > MAX_FILE_SIZE) {
@@ -152,25 +173,40 @@ export class PdfPreviewComponent implements OnInit, OnDestroy, OnChanges {
                 },
             });
         } else if (this.attachmentUnit()) {
-            const finalHiddenPages = this.getHiddenPages().join(',');
+            const finalHiddenPages = this.getHiddenPages();
             this.attachmentToBeEdited.set(this.attachmentUnit()!.attachment!);
-            this.attachmentToBeEdited()!.version!++;
+            //this.attachmentToBeEdited()!.version!++;
             this.attachmentToBeEdited()!.uploadDate = dayjs();
 
             const formData = new FormData();
             formData.append('file', pdfFile);
             formData.append('attachment', objectToJsonBlob(this.attachmentToBeEdited()!));
             formData.append('attachmentUnit', objectToJsonBlob(this.attachmentUnit()!));
 
-            this.attachmentUnitService.update(this.attachmentUnit()!.lecture!.id!, this.attachmentUnit()!.id!, formData, undefined, finalHiddenPages).subscribe({
-                next: async () => {
-                    this.alertService.success('artemisApp.attachment.pdfPreview.attachmentUpdateSuccess');
-                    this.router.navigate(['course-management', this.course()?.id, 'lectures', this.attachmentUnit()!.lecture!.id, 'unit-management']);
-                },
-                error: (error) => {
-                    this.alertService.error('artemisApp.attachment.pdfPreview.attachmentUpdateError', { error: error.message });
-                },
-            });
+            if (this.hiddenPagesChanged()) {
+                const pdfFileWithHiddenPages = await this.createHiddenVersionOfAttachment(finalHiddenPages);
+                const attachmentWithHiddenPages = cloneDeep(this.attachmentToBeEdited()!);
+
+                this.attachmentService.update(attachmentWithHiddenPages.id!, attachmentWithHiddenPages, undefined, pdfFileWithHiddenPages).subscribe({
+                    next: () => {
+                        this.alertService.success('artemisApp.attachment.pdfPreview.hiddenAttachmentUpdateSuccess');
+                        this.attachmentUnitService
+                            .update(this.attachmentUnit()!.lecture!.id!, this.attachmentUnit()!.id!, formData, undefined, finalHiddenPages.join(','))
+                            .subscribe({
+                                next: () => {
+                                    this.alertService.success('artemisApp.attachment.pdfPreview.attachmentUpdateSuccess');
+                                    this.router.navigate(['course-management', this.course()?.id, 'lectures', this.attachmentUnit()!.lecture!.id, 'unit-management']);
+                                },
+                                error: (error) => {
+                                    this.alertService.error('artemisApp.attachment.pdfPreview.attachmentUpdateError', { error: error.message });
+                                },
+                            });
+                    },
+                    error: (error) => {
+                        this.alertService.error('artemisApp.attachment.pdfPreview.hiddenAttachmentUpdateError', { error: error.message });
+                    },
+                });
+            }
         }
     }
 
@@ -255,6 +291,30 @@ export class PdfPreviewComponent implements OnInit, OnDestroy, OnChanges {
         this.hiddenPages.set(updatedHiddenPages);
     }
 
+    /**
+     * Creates a hidden version of the current PDF attachment by removing specified pages.
+     *
+     * @param hiddenPages - An array of page numbers to be removed from the original PDF.
+     * @returns A promise that resolves to a new `File` object representing the modified PDF, or undefined if an error occurs.
+     */
+    async createHiddenVersionOfAttachment(hiddenPages: number[]) {
+        try {
+            const fileName = this.attachmentUnit()!.attachment!.name;
+            const existingPdfBytes = await this.currentPdfBlob()!.arrayBuffer();
+            const hiddenPdfDoc = await PDFDocument.load(existingPdfBytes);
+
+            const pagesToDelete = hiddenPages.map((page) => page - 1).sort((a, b) => b - a);
+            pagesToDelete.forEach((pageIndex) => {
+                hiddenPdfDoc.removePage(pageIndex);
+            });
+
+            const pdfBytes = await hiddenPdfDoc.save();
+            return new File([pdfBytes], `${fileName}.pdf`, { type: 'application/pdf' });
+        } catch (error) {
+            this.alertService.error('artemisApp.attachment.pdfPreview.pageDeleteError', { error: error.message });
+        }
+    }
+
     /**
      * Adds a selected PDF file at the end of the current PDF document.
      * @param event - The event containing the file input.

src/main/webapp/app/overview/course-lectures/attachment-unit/attachment-unit.component.ts

@@ -49,9 +49,10 @@ export class AttachmentUnitComponent extends LectureUnitDirective<AttachmentUnit
     handleDownload() {
         this.logEvent();
 
-        if (this.lectureUnit().attachment?.link) {
-            const link = this.lectureUnit().attachment!.link!;
-            this.fileService.downloadFile(this.fileService.replaceAttachmentPrefixAndUnderscores(link));
+        const link = this.lectureUnit().attachment?.hiddenLink || this.lectureUnit().attachment?.link; // Prefer hiddenLink if available
+        if (link) {
+            const sanitizedLink = this.fileService.replaceAttachmentPrefixAndUnderscores(link);
+            this.fileService.downloadFile(sanitizedLink);
             this.onCompletion.emit({ lectureUnit: this.lectureUnit(), completed: true });
         }
     }