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blank pages returns removed pages for verification #1574 (#1619)

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separated blank and non-blank pages and created unified ZIP archive

Co-authored-by: mannam <101550345+ManoharMannam@users.noreply.github.com>
Co-authored-by: Anthony Stirling <77850077+Frooodle@users.noreply.github.com>
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Manohar Mannam 2024-08-03 15:00:53 +05:30 committed by GitHub
parent 191e79da18
commit ea6d4a293e
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1 changed files with 53 additions and 29 deletions
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82
src/main/java/stirling/software/SPDF/controller/api/misc/BlankPageController.java
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@ -1,12 +1,12 @@
package stirling.software.SPDF.controller.api.misc; package stirling.software.SPDF.controller.api.misc;
import java.awt.image.BufferedImage; import java.awt.image.BufferedImage;
import java.io.ByteArrayOutputStream;
import java.io.IOException; import java.io.IOException;
import java.util.ArrayList; import java.util.ArrayList;
import java.util.Collections;
import java.util.List; import java.util.List;
import java.util.stream.Collectors; import java.util.zip.ZipEntry;
import java.util.stream.IntStream; import java.util.zip.ZipOutputStream;
import org.apache.pdfbox.Loader; import org.apache.pdfbox.Loader;
import org.apache.pdfbox.pdmodel.PDDocument; import org.apache.pdfbox.pdmodel.PDDocument;
@ -17,6 +17,7 @@ import org.apache.pdfbox.text.PDFTextStripper;
import org.slf4j.Logger; import org.slf4j.Logger;
import org.slf4j.LoggerFactory; import org.slf4j.LoggerFactory;
import org.springframework.http.HttpStatus; import org.springframework.http.HttpStatus;
import org.springframework.http.MediaType;
import org.springframework.http.ResponseEntity; import org.springframework.http.ResponseEntity;
import org.springframework.web.bind.annotation.ModelAttribute; import org.springframework.web.bind.annotation.ModelAttribute;
import org.springframework.web.bind.annotation.PostMapping; import org.springframework.web.bind.annotation.PostMapping;
@ -50,31 +51,31 @@ public class BlankPageController {
int threshold = request.getThreshold(); int threshold = request.getThreshold();
float whitePercent = request.getWhitePercent(); float whitePercent = request.getWhitePercent();
PDDocument document = null; try (PDDocument document = Loader.loadPDF(inputFile.getBytes())) {
try {
document = Loader.loadPDF(inputFile.getBytes());
PDPageTree pages = document.getDocumentCatalog().getPages(); PDPageTree pages = document.getDocumentCatalog().getPages();
PDFTextStripper textStripper = new PDFTextStripper(); PDFTextStripper textStripper = new PDFTextStripper();
List<Integer> pagesToKeepIndex = new ArrayList<>(); List<PDPage> nonBlankPages = new ArrayList<>();
List<PDPage> blankPages = new ArrayList<>();
int pageIndex = 0; int pageIndex = 0;
PDFRenderer pdfRenderer = new PDFRenderer(document); PDFRenderer pdfRenderer = new PDFRenderer(document);
pdfRenderer.setSubsamplingAllowed(true); pdfRenderer.setSubsamplingAllowed(true);
for (PDPage page : pages) { for (PDPage page : pages) {
logger.info("checking page " + pageIndex); logger.info("checking page {}", pageIndex);
textStripper.setStartPage(pageIndex + 1); textStripper.setStartPage(pageIndex + 1);
textStripper.setEndPage(pageIndex + 1); textStripper.setEndPage(pageIndex + 1);
String pageText = textStripper.getText(document); String pageText = textStripper.getText(document);
boolean hasText = !pageText.trim().isEmpty(); boolean hasText = !pageText.trim().isEmpty();
Boolean blank = true; boolean blank = true;
if (hasText) { if (hasText) {
logger.info("page " + pageIndex + " has text, not blank"); logger.info("page {} has text, not blank", pageIndex);
blank = false; blank = false;
} else { } else {
boolean hasImages = PdfUtils.hasImagesOnPage(page); boolean hasImages = PdfUtils.hasImagesOnPage(page);
if (hasImages) { if (hasImages) {
logger.info("page " + pageIndex + " has image, running blank detection"); logger.info("page {} has image, running blank detection", pageIndex);
// Render image and save as temp file // Render image and save as temp file
BufferedImage image = pdfRenderer.renderImageWithDPI(pageIndex, 30); BufferedImage image = pdfRenderer.renderImageWithDPI(pageIndex, 30);
blank = isBlankImage(image, threshold, whitePercent, threshold); blank = isBlankImage(image, threshold, whitePercent, threshold);
@ -82,34 +83,57 @@ public class BlankPageController {
} }
if (blank) { if (blank) {
logger.info("Skipping, Image was blank for page #" + pageIndex); logger.info("Skipping, Image was blank for page #{}", pageIndex);
blankPages.add(page);
} else { } else {
logger.info("page " + pageIndex + " has image which is not blank"); logger.info("page {} has image which is not blank", pageIndex);
pagesToKeepIndex.add(pageIndex); nonBlankPages.add(page);
} }
pageIndex++; pageIndex++;
} }
// Remove pages not present in pagesToKeepIndex
List<Integer> pageIndices = ByteArrayOutputStream baos = new ByteArrayOutputStream();
IntStream.range(0, pages.getCount()).boxed().collect(Collectors.toList()); ZipOutputStream zos = new ZipOutputStream(baos);
Collections.reverse(pageIndices); // Reverse to prevent index shifting during removal
for (Integer i : pageIndices) { String filename =
if (!pagesToKeepIndex.contains(i)) { Filenames.toSimpleFileName(inputFile.getOriginalFilename())
pages.remove(i); .replaceFirst("[.][^.]+$", "");
}
if (!nonBlankPages.isEmpty()) {
createZipEntry(zos, nonBlankPages, filename + "_nonBlankPages.pdf");
} else {
createZipEntry(zos, blankPages, filename + "_allBlankPages.pdf");
} }
return WebResponseUtils.pdfDocToWebResponse( if (!nonBlankPages.isEmpty() && !blankPages.isEmpty()) {
document, createZipEntry(zos, blankPages, filename + "_blankPages.pdf");
Filenames.toSimpleFileName(inputFile.getOriginalFilename()) }
.replaceFirst("[.][^.]+$", "")
+ "_blanksRemoved.pdf"); zos.close();
logger.info("Returning ZIP file: {}", filename + "_processed.zip");
return WebResponseUtils.boasToWebResponse(
baos, filename + "_processed.zip", MediaType.APPLICATION_OCTET_STREAM);
} catch (IOException e) { } catch (IOException e) {
logger.error("exception", e); logger.error("exception", e);
return new ResponseEntity<>(HttpStatus.INTERNAL_SERVER_ERROR); return new ResponseEntity<>(HttpStatus.INTERNAL_SERVER_ERROR);
} finally { }
if (document != null) document.close(); }
public void createZipEntry(ZipOutputStream zos, List<PDPage> pages, String entryName)
throws IOException {
try (PDDocument document = new PDDocument()) {
for (PDPage page : pages) {
document.addPage(page);
}
ZipEntry zipEntry = new ZipEntry(entryName);
zos.putNextEntry(zipEntry);
document.save(zos);
zos.closeEntry();
} }
} }