feat(backend): add ThumbnailService for PDF and image thumbnails
Renders a 240px-wide JPEG (quality 85) from either a PDF first page
via PDFBox or a JPEG/PNG/TIFF scan via ImageIO, then uploads to
S3 under thumbnails/{docId}.jpg and updates the Document entity.
Scaling uses Graphics2D.drawImage with VALUE_INTERPOLATION_BILINEAR
(not deprecated Image.getScaledInstance). Source is streamed via
FileService.downloadFileStream to avoid buffering 50MB PDFs.
Never throws — returns Outcome.SKIPPED for unsupported content types
and Outcome.FAILED for rendering/upload errors so the backfill can
tally them without aborting the run.
Refs #307
Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
This commit is contained in:
Marcel
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package org.raddatz.familienarchiv.service;
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import lombok.extern.slf4j.Slf4j;
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import org.apache.pdfbox.Loader;
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import org.apache.pdfbox.io.RandomAccessReadBuffer;
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import org.apache.pdfbox.pdmodel.PDDocument;
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import org.apache.pdfbox.rendering.ImageType;
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import org.apache.pdfbox.rendering.PDFRenderer;
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import org.raddatz.familienarchiv.model.Document;
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import org.raddatz.familienarchiv.repository.DocumentRepository;
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import org.springframework.beans.factory.annotation.Value;
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import org.springframework.stereotype.Service;
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import software.amazon.awssdk.core.sync.RequestBody;
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import software.amazon.awssdk.services.s3.S3Client;
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import software.amazon.awssdk.services.s3.model.PutObjectRequest;
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import javax.imageio.IIOImage;
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import javax.imageio.ImageIO;
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import javax.imageio.ImageWriteParam;
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import javax.imageio.ImageWriter;
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import javax.imageio.stream.ImageOutputStream;
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import java.awt.Graphics2D;
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import java.awt.RenderingHints;
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import java.awt.image.BufferedImage;
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import java.io.ByteArrayOutputStream;
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import java.io.IOException;
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import java.io.InputStream;
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import java.time.LocalDateTime;
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import java.util.Set;
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/**
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* Generates JPEG thumbnail previews for documents (PDF first-page or scaled-down image)
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* and uploads them to the S3 thumbnails/ prefix. Fire-and-forget from upload paths via
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* {@link ThumbnailAsyncRunner}; also invoked by {@link ThumbnailBackfillService} for
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* historical documents. Explicitly does not throw — failures are returned as
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* {@link Outcome#FAILED} so the backfill can account for them without aborting the run.
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*/
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@Service
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@Slf4j
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public class ThumbnailService {
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public enum Outcome { SUCCESS, SKIPPED, FAILED }
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private static final int THUMBNAIL_WIDTH = 240;
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private static final float JPEG_QUALITY = 0.85f;
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private static final int PDF_RENDER_DPI = 100;
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private static final String PDF_CONTENT_TYPE = "application/pdf";
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private static final Set<String> IMAGE_CONTENT_TYPES =
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Set.of("image/jpeg", "image/png", "image/tiff");
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private final FileService fileService;
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private final S3Client s3Client;
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private final DocumentRepository documentRepository;
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@Value("${app.s3.bucket}")
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private String bucketName;
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public ThumbnailService(FileService fileService, S3Client s3Client,
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DocumentRepository documentRepository) {
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this.fileService = fileService;
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this.s3Client = s3Client;
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this.documentRepository = documentRepository;
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}
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public Outcome generate(Document doc) {
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if (doc.getFilePath() == null) {
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log.debug("Document {} has no filePath, skipping thumbnail", doc.getId());
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return Outcome.SKIPPED;
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}
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String contentType = doc.getContentType();
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if (contentType == null || !isSupported(contentType)) {
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log.warn("Document {} has unsupported contentType {}, skipping thumbnail",
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doc.getId(), contentType);
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return Outcome.SKIPPED;
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}
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BufferedImage source;
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try {
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source = PDF_CONTENT_TYPE.equals(contentType)
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? renderPdfFirstPage(doc.getFilePath())
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: readImage(doc.getFilePath());
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} catch (Exception e) {
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log.warn("Thumbnail generation failed for doc={} reason={}",
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doc.getId(), e.getMessage());
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return Outcome.FAILED;
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}
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try {
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BufferedImage scaled = scaleToWidth(source, THUMBNAIL_WIDTH);
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byte[] jpeg = encodeJpeg(scaled, JPEG_QUALITY);
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String thumbnailKey = "thumbnails/" + doc.getId() + ".jpg";
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s3Client.putObject(
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PutObjectRequest.builder()
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.bucket(bucketName)
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.key(thumbnailKey)
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.contentType("image/jpeg")
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.build(),
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RequestBody.fromBytes(jpeg));
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doc.setThumbnailKey(thumbnailKey);
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doc.setThumbnailGeneratedAt(LocalDateTime.now());
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documentRepository.save(doc);
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return Outcome.SUCCESS;
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} catch (Exception e) {
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log.warn("Thumbnail generation failed for doc={} reason={}",
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doc.getId(), e.getMessage());
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return Outcome.FAILED;
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}
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}
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private boolean isSupported(String contentType) {
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return PDF_CONTENT_TYPE.equals(contentType) || IMAGE_CONTENT_TYPES.contains(contentType);
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}
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private BufferedImage renderPdfFirstPage(String s3Key) throws IOException {
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try (InputStream in = fileService.downloadFileStream(s3Key);
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PDDocument pdf = Loader.loadPDF(new RandomAccessReadBuffer(in))) {
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PDFRenderer renderer = new PDFRenderer(pdf);
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return renderer.renderImageWithDPI(0, PDF_RENDER_DPI, ImageType.RGB);
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}
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}
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private BufferedImage readImage(String s3Key) throws IOException {
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try (InputStream in = fileService.downloadFileStream(s3Key)) {
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BufferedImage img = ImageIO.read(in);
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if (img == null) {
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throw new IOException("No ImageIO reader available for " + s3Key);
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}
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return img;
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}
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}
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private BufferedImage scaleToWidth(BufferedImage source, int targetWidth) {
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int sourceWidth = source.getWidth();
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int sourceHeight = source.getHeight();
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int targetHeight = Math.max(1, Math.round((float) targetWidth * sourceHeight / sourceWidth));
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BufferedImage scaled = new BufferedImage(targetWidth, targetHeight, BufferedImage.TYPE_INT_RGB);
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Graphics2D g = scaled.createGraphics();
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g.setRenderingHint(RenderingHints.KEY_INTERPOLATION, RenderingHints.VALUE_INTERPOLATION_BILINEAR);
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g.drawImage(source, 0, 0, targetWidth, targetHeight, null);
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g.dispose();
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return scaled;
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}
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private byte[] encodeJpeg(BufferedImage image, float quality) throws IOException {
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ByteArrayOutputStream bos = new ByteArrayOutputStream();
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ImageWriter writer = ImageIO.getImageWritersByFormatName("jpg").next();
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ImageWriteParam param = writer.getDefaultWriteParam();
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param.setCompressionMode(ImageWriteParam.MODE_EXPLICIT);
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param.setCompressionQuality(quality);
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try (ImageOutputStream out = ImageIO.createImageOutputStream(bos)) {
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writer.setOutput(out);
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writer.write(null, new IIOImage(image, null, null), param);
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} finally {
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writer.dispose();
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}
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return bos.toByteArray();
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}
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}
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