Lectures: Add hide/show functionality to PDF Preview Component

src/main/java/de/tum/cit/aet/artemis/core/service/FilePathService.java

@@ -150,6 +150,10 @@ private static Path actualPathForPublicAttachmentUnitFilePath(URI publicPath, St
             String attachmentUnitId = path.getName(4).toString();
             return getAttachmentUnitFilePath().resolve(Path.of(attachmentUnitId, filename));
         }
+        else if (publicPath.toString().contains("/student")) {
+            String attachmentUnitId = path.getName(4).toString();
+            return getAttachmentUnitFilePath().resolve(Path.of(attachmentUnitId, "student", filename));
+        }
         try {
             String attachmentUnitId = path.getName(4).toString();
             String slideId = path.getName(6).toString();
@@ -244,6 +248,9 @@ public static URI publicPathForActualPath(Path path, @Nullable Long entityId) {
     }
 
     private static URI publicPathForActualAttachmentUnitFilePath(Path path, String filename, String id) {
+        if (path.toString().contains("/student")) {
+            return URI.create("/api/files/attachments/attachment-unit/" + id + "/student/" + filename);
+        }
         if (!path.toString().contains("/slide")) {
             return URI.create("/api/files/attachments/attachment-unit/" + id + "/" + filename);
         }

src/main/java/de/tum/cit/aet/artemis/core/web/FileResource.java

@@ -476,7 +476,7 @@ public ResponseEntity<byte[]> getLecturePdfAttachmentsMerged(@PathVariable Long
      * @return The requested file, 403 if the logged-in user is not allowed to access it, or 404 if the file doesn't exist
      */
     @GetMapping("files/attachments/attachment-unit/{attachmentUnitId}/*")
-    @EnforceAtLeastStudent
+    @EnforceAtLeastTutor
     public ResponseEntity<byte[]> getAttachmentUnitAttachment(@PathVariable Long attachmentUnitId) {
         log.debug("REST request to get the file for attachment unit {} for students", attachmentUnitId);
         AttachmentUnit attachmentUnit = attachmentUnitRepository.findByIdElseThrow(attachmentUnitId);
@@ -565,6 +565,30 @@ public ResponseEntity<byte[]> getAttachmentUnitAttachmentSlide(@PathVariable Lon
         }
     }
 
+    /**
+     * GET files/attachments/attachment-unit/{attachmentUnitId}/student/* : Get the student version of attachment unit by attachment unit id
+     *
+     * @param attachmentUnitId ID of the attachment unit, the student version belongs to
+     * @return The requested file, 403 if the logged-in user is not allowed to access it, or 404 if the file doesn't exist
+     */
+    @GetMapping("files/attachments/attachment-unit/{attachmentUnitId}/student/*")
+    @EnforceAtLeastStudent
+    public ResponseEntity<byte[]> getAttachmentUnitStudentVersion(@PathVariable Long attachmentUnitId) {
+        log.debug("REST request to get the student version of attachment Unit : {}", attachmentUnitId);
+        AttachmentUnit attachmentUnit = attachmentUnitRepository.findByIdElseThrow(attachmentUnitId);
+        Attachment attachment = attachmentUnit.getAttachment();
+
+        // check if hidden link is available in the attachment
+        String studentVersion = attachment.getStudentVersion();
+        if (studentVersion == null) {
+            return buildFileResponse(getActualPathFromPublicPathString(attachment.getLink()), false);
+        }
+
+        String fileName = studentVersion.substring(studentVersion.lastIndexOf("/") + 1);
+
+        return buildFileResponse(FilePathService.getAttachmentUnitFilePath().resolve(Path.of(attachmentUnit.getId().toString(), "student")), fileName, false);
+    }
+
     /**
      * Builds the response with headers, body and content type for specified path containing the file name
      *

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 = "student_version")
+    private String studentVersion;
+
     // 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 getStudentVersion() {
+        return studentVersion;
+    }
+
+    public void setStudentVersion(String studentVersion) {
+        this.studentVersion = studentVersion;
+    }
+
     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/domain/Slide.java

@@ -1,5 +1,7 @@
 package de.tum.cit.aet.artemis.lecture.domain;
 
+import java.util.Date;
+
 import jakarta.persistence.Column;
 import jakarta.persistence.Entity;
 import jakarta.persistence.JoinColumn;
@@ -27,6 +29,9 @@ public class Slide extends DomainObject {
     @Column(name = "slide_number")
     private int slideNumber;
 
+    @Column(name = "hidden")
+    private Date hidden;
+
     public AttachmentUnit getAttachmentUnit() {
         return attachmentUnit;
     }
@@ -50,4 +55,12 @@ public int getSlideNumber() {
     public void setSlideNumber(int slideNumber) {
         this.slideNumber = slideNumber;
     }
+
+    public Date getHidden() {
+        return hidden;
+    }
+
+    public void setHidden(Date hidden) {
+        this.hidden = hidden;
+    }
 }

src/main/java/de/tum/cit/aet/artemis/lecture/repository/SlideRepository.java

@@ -2,7 +2,11 @@
 
 import static de.tum.cit.aet.artemis.core.config.Constants.PROFILE_CORE;
 
+import java.util.List;
+
 import org.springframework.context.annotation.Profile;
+import org.springframework.data.jpa.repository.Query;
+import org.springframework.data.repository.query.Param;
 import org.springframework.stereotype.Repository;
 
 import de.tum.cit.aet.artemis.core.repository.base.ArtemisJpaRepository;
@@ -17,4 +21,17 @@ public interface SlideRepository extends ArtemisJpaRepository<Slide, Long> {
 
     Slide findSlideByAttachmentUnitIdAndSlideNumber(Long attachmentUnitId, Integer slideNumber);
 
+    /**
+     * Finds the list of hidden slide IDs for a specific attachment unit ID.
+     *
+     * @param attachmentUnitId The ID of the attachment unit.
+     * @return List of hidden slide IDs.
+     */
+    @Query("""
+            SELECT s.slideNumber
+            FROM Slide s
+            WHERE s.attachmentUnit.id = :attachmentUnitId AND s.hidden IS NOT NULL
+            """)
+    List<Integer> findHiddenSlideNumbersByAttachmentUnitId(@Param("attachmentUnitId") Long attachmentUnitId);
+
 }

src/main/java/de/tum/cit/aet/artemis/lecture/service/AttachmentUnitService.java

@@ -108,10 +108,11 @@ public AttachmentUnit createAttachmentUnit(AttachmentUnit attachmentUnit, Attach
      * @param updateAttachment       The new attachment data.
      * @param updateFile             The optional file.
      * @param keepFilename           Whether to keep the original filename or not.
+     * @param hiddenPages            The hidden pages of attachment unit.
      * @return The updated attachment unit.
      */
     public AttachmentUnit updateAttachmentUnit(AttachmentUnit existingAttachmentUnit, AttachmentUnit updateUnit, Attachment updateAttachment, MultipartFile updateFile,
-            boolean keepFilename) {
+            boolean keepFilename, String hiddenPages) {
         Set<CompetencyLectureUnitLink> existingCompetencyLinks = new HashSet<>(existingAttachmentUnit.getCompetencyLinks());
 
         existingAttachmentUnit.setDescription(updateUnit.getDescription());
@@ -145,7 +146,7 @@ public AttachmentUnit updateAttachmentUnit(AttachmentUnit existingAttachmentUnit
             }
             // Split the updated file into single slides only if it is a pdf
             if (Objects.equals(FilenameUtils.getExtension(updateFile.getOriginalFilename()), "pdf")) {
-                slideSplitterService.splitAttachmentUnitIntoSingleSlides(savedAttachmentUnit);
+                slideSplitterService.splitAttachmentUnitIntoSingleSlides(savedAttachmentUnit, hiddenPages);
             }
             if (pyrisWebhookService.isPresent() && irisSettingsRepository.isPresent()) {
                 pyrisWebhookService.get().autoUpdateAttachmentUnitsInPyris(savedAttachmentUnit.getLecture().getCourse().getId(), List.of(savedAttachmentUnit));

src/main/java/de/tum/cit/aet/artemis/lecture/service/LectureUnitImportService.java

@@ -119,7 +119,7 @@ public LectureUnit importLectureUnit(final LectureUnit importedLectureUnit) {
                 attachment.setAttachmentUnit(attachmentUnit);
                 attachmentRepository.save(attachment);
                 if (attachment.getLink().endsWith(".pdf")) {
-                    slideSplitterService.splitAttachmentUnitIntoSingleSlides(attachmentUnit);
+                    slideSplitterService.splitAttachmentUnitIntoSingleSlides(attachmentUnit, null);
                 }
                 attachmentUnit.setAttachment(attachment);
                 return attachmentUnit;

src/main/java/de/tum/cit/aet/artemis/lecture/service/LectureUnitProcessingService.java

@@ -109,7 +109,7 @@ public List<AttachmentUnit> splitAndSaveUnits(LectureUnitSplitInformationDTO lec
 
                 MultipartFile multipartFile = fileService.convertByteArrayToMultipart(lectureUnit.unitName(), ".pdf", outputStream.toByteArray());
                 AttachmentUnit savedAttachmentUnit = attachmentUnitService.createAttachmentUnit(attachmentUnit, attachment, lecture, multipartFile, true);
-                slideSplitterService.splitAttachmentUnitIntoSingleSlides(documentUnits.getFirst(), savedAttachmentUnit, multipartFile.getOriginalFilename());
+                slideSplitterService.splitAttachmentUnitIntoSingleSlides(documentUnits.getFirst(), savedAttachmentUnit, multipartFile.getOriginalFilename(), "");
                 documentUnits.getFirst().close(); // make sure to close the document
                 units.add(savedAttachmentUnit);
             }

src/main/java/de/tum/cit/aet/artemis/lecture/service/SlideSplitterService.java

@@ -8,6 +8,11 @@
 import java.io.IOException;
 import java.net.URI;
 import java.nio.file.Path;
+import java.time.LocalDate;
+import java.util.Arrays;
+import java.util.Collections;
+import java.util.List;
+import java.util.Optional;
 
 import javax.imageio.ImageIO;
 
@@ -39,6 +44,8 @@ public class SlideSplitterService {
 
     private static final Logger log = LoggerFactory.getLogger(SlideSplitterService.class);
 
+    static final LocalDate FOREVER = LocalDate.of(9999, 12, 31);
+
     private final FileService fileService;
 
     private final SlideRepository slideRepository;
@@ -52,14 +59,15 @@ public SlideSplitterService(FileService fileService, SlideRepository slideReposi
      * Splits an Attachment Unit file into single slides and saves them as PNG files asynchronously.
      *
      * @param attachmentUnit The attachment unit to which the slides belong.
+     * @param hiddenPages    The hidden pages of the attachment unit.
      */
     @Async
-    public void splitAttachmentUnitIntoSingleSlides(AttachmentUnit attachmentUnit) {
+    public void splitAttachmentUnitIntoSingleSlides(AttachmentUnit attachmentUnit, String hiddenPages) {
         Path attachmentPath = FilePathService.actualPathForPublicPath(URI.create(attachmentUnit.getAttachment().getLink()));
         File file = attachmentPath.toFile();
         try (PDDocument document = Loader.loadPDF(file)) {
             String pdfFilename = file.getName();
-            splitAttachmentUnitIntoSingleSlides(document, attachmentUnit, pdfFilename);
+            splitAttachmentUnitIntoSingleSlides(document, attachmentUnit, pdfFilename, hiddenPages);
         }
         catch (IOException e) {
             log.error("Error while splitting Attachment Unit {} into single slides", attachmentUnit.getId(), e);
@@ -68,19 +76,23 @@ public void splitAttachmentUnitIntoSingleSlides(AttachmentUnit attachmentUnit) {
     }
 
     /**
-     * Splits an Attachment Unit file into single slides and saves them as PNG files. Document is closed where this method is called.
+     * Splits an Attachment Unit file into single slides and saves them as PNG files or updates existing slides.
      *
      * @param attachmentUnit The attachment unit to which the slides belong.
      * @param document       The PDF document that is already loaded.
      * @param pdfFilename    The name of the PDF file.
+     * @param hiddenPages    The hidden pages of the attachment unit.
      */
-    public void splitAttachmentUnitIntoSingleSlides(PDDocument document, AttachmentUnit attachmentUnit, String pdfFilename) {
+    public void splitAttachmentUnitIntoSingleSlides(PDDocument document, AttachmentUnit attachmentUnit, String pdfFilename, String hiddenPages) {
         log.debug("Splitting Attachment Unit file {} into single slides", attachmentUnit.getAttachment().getName());
         try {
             String fileNameWithOutExt = FilenameUtils.removeExtension(pdfFilename);
             int numPages = document.getNumberOfPages();
             PDFRenderer pdfRenderer = new PDFRenderer(document);
 
+            List<Integer> hiddenPagesList = hiddenPages != null && !hiddenPages.isEmpty() ? Arrays.stream(hiddenPages.split(",")).map(Integer::parseInt).toList()
+                    : Collections.emptyList();
+
             for (int page = 0; page < numPages; page++) {
                 BufferedImage bufferedImage = pdfRenderer.renderImageWithDPI(page, 72, ImageType.RGB);
                 byte[] imageInByte = bufferedImageToByteArray(bufferedImage, "png");
@@ -89,11 +101,15 @@ public void splitAttachmentUnitIntoSingleSlides(PDDocument document, AttachmentU
                 MultipartFile slideFile = fileService.convertByteArrayToMultipart(filename, ".png", imageInByte);
                 Path savePath = fileService.saveFile(slideFile, FilePathService.getAttachmentUnitFilePath().resolve(attachmentUnit.getId().toString()).resolve("slide")
                         .resolve(String.valueOf(slideNumber)).resolve(filename));
-                Slide slideEntity = new Slide();
-                slideEntity.setSlideImagePath(FilePathService.publicPathForActualPath(savePath, (long) slideNumber).toString());
-                slideEntity.setSlideNumber(slideNumber);
-                slideEntity.setAttachmentUnit(attachmentUnit);
-                slideRepository.save(slideEntity);
+
+                Optional<Slide> existingSlideOpt = Optional.ofNullable(slideRepository.findSlideByAttachmentUnitIdAndSlideNumber(attachmentUnit.getId(), slideNumber));
+                Slide slide = existingSlideOpt.orElseGet(Slide::new);
+                slide.setSlideImagePath(FilePathService.publicPathForActualPath(savePath, (long) slideNumber).toString());
+                slide.setSlideNumber(slideNumber);
+                slide.setAttachmentUnit(attachmentUnit);
+                slide.setHidden(hiddenPagesList.contains(slideNumber) ? java.sql.Date.valueOf(FOREVER) : null);
+                slideRepository.save(slide);
+
             }
         }
         catch (IOException e) {

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

@@ -101,19 +101,20 @@ public ResponseEntity<Attachment> createAttachment(@RequestPart Attachment attac
     }
 
     /**
-     * PUT /attachments/:id : Updates an existing attachment.
+     * PUT /attachments/:id : Updates an existing attachment, optionally handling student version of files as well.
      *
      * @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 studentVersion   the file to add as student 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 studentVersion, @RequestParam(value = "notificationText", required = false) String notificationText) {
         log.debug("REST request to update Attachment : {}", attachment);
         attachment.setId(attachmentId);
 
@@ -131,6 +132,20 @@ public ResponseEntity<Attachment> updateAttachment(@PathVariable Long attachment
             this.fileService.evictCacheForPath(FilePathService.actualPathForPublicPathOrThrow(oldPath));
         }
 
+        if (studentVersion != null) {
+            // Update student version of attachment
+            Path basePath = FilePathService.getAttachmentUnitFilePath().resolve(originalAttachment.getAttachmentUnit().getId().toString());
+            Path savePath = fileService.saveFile(studentVersion, basePath.resolve("student"), true);
+            attachment.setStudentVersion(FilePathService.publicPathForActualPath(savePath, originalAttachment.getAttachmentUnit().getId()).toString());
+
+            // Delete the old student version
+            if (originalAttachment.getStudentVersion() != null) {
+                URI oldHiddenPath = URI.create(originalAttachment.getStudentVersion());
+                fileService.schedulePathForDeletion(FilePathService.actualPathForPublicPathOrThrow(oldHiddenPath), 0);
+                this.fileService.evictCacheForPath(FilePathService.actualPathForPublicPathOrThrow(oldHiddenPath));
+            }
+        }
+
         Attachment result = attachmentRepository.save(attachment);
         if (notificationText != null) {
             groupNotificationService.notifyStudentGroupAboutAttachmentChange(result, notificationText);