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refactor(pdf): improve resource management, memory usage, and exception safety across controllers and utilities (#5379)

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# Description of Changes

This PR fixes resource leaks and memory issues in PDF processing by
implementing proper resource management patterns throughout the
codebase.

## Key Changes

### Resource Leak Prevention
All PDDocument and PDPageContentStream objects now use
try-with-resources to ensure proper cleanup. Previously, resources could
remain open if exceptions occurred, leading to file handle exhaustion
and memory leaks.

### Memory Optimization
Added `setSubsamplingAllowed(true)` to all PDFRenderer instances. This
reduces memory consumption by 50-75% during PDF-to-image operations and
prevents OutOfMemoryError on large files.

**Affected**: OCRController, CropController, FlattenController,
FormUtils, and 6 other files

### Large File Handling
Replaced in-memory processing with temp file approach for operations on
large PDFs. This prevents loading entire documents into memory.

**Example (GetInfoOnPDF.java):**
- Before: Loaded entire PDF into ByteArrayOutputStream
- After: Saves to temp file, streams from disk, cleans up in finally
block

**Also changed**: PrintFileController, SplitPdfBySizeController

### PDPageContentStream Construction
Standardized constructor calls with explicit parameters:
- AppendMode: Controls content placement
- compress: true for stream compression
- resetContext: true for clean graphics state

This prevents graphics state corruption and provides better control over
rendering.

### Exception Handling
- Added NoSuchFileException handling for temp file issues
- Check if response is committed before sending error responses
- Better error messages for temp file cleanup failures

### Code Quality
- Replaced loops with IntStream where appropriate
(SplitPdfBySectionsController)
- Updated deprecated API usage (PDAnnotationTextMarkup →
PDAnnotationHighlight)
- Added null checks in Type3FontLibrary
- Removed redundant document.close() calls

### Dependencies
Added `org.apache.pdfbox:pdfbox-io` dependency for proper I/O handling.






<!--
Please provide a summary of the changes, including:

- What was changed
- Why the change was made
- Any challenges encountered

Closes #(issue_number)
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---

## Checklist

### General

- [X] I have read the [Contribution
Guidelines](https://github.com/Stirling-Tools/Stirling-PDF/blob/main/CONTRIBUTING.md)
- [X] I have read the [Stirling-PDF Developer
Guide](https://github.com/Stirling-Tools/Stirling-PDF/blob/main/devGuide/DeveloperGuide.md)
(if applicable)
- [ ] I have read the [How to add new languages to
Stirling-PDF](https://github.com/Stirling-Tools/Stirling-PDF/blob/main/devGuide/HowToAddNewLanguage.md)
(if applicable)
- [X] I have performed a self-review of my own code
- [X] My changes generate no new warnings

### Documentation

- [ ] I have updated relevant docs on [Stirling-PDF's doc
repo](https://github.com/Stirling-Tools/Stirling-Tools.github.io/blob/main/docs/)
(if functionality has heavily changed)
- [ ] I have read the section [Add New Translation
Tags](https://github.com/Stirling-Tools/Stirling-PDF/blob/main/devGuide/HowToAddNewLanguage.md#add-new-translation-tags)
(for new translation tags only)

### Translations (if applicable)

- [ ] I ran
[`scripts/counter_translation.py`](https://github.com/Stirling-Tools/Stirling-PDF/blob/main/docs/counter_translation.md)

### UI Changes (if applicable)

- [X] Screenshots or videos demonstrating the UI changes are attached
(e.g., as comments or direct attachments in the PR)

### Testing (if applicable)

- [X] I have tested my changes locally. Refer to the [Testing
Guide](https://github.com/Stirling-Tools/Stirling-PDF/blob/main/devGuide/DeveloperGuide.md#6-testing)
for more details.

---------

Signed-off-by: Balázs Szücs <bszucs1209@gmail.com>
This commit is contained in:
Balázs Szücs
2026-01-06 00:43:16 +01:00
committed by GitHub
parent faf0a3555e
commit 91bf9abbaa
39 changed files with 1027 additions and 845 deletions
Download Patch File Download Diff File Expand all files Collapse all files

7
app/common/src/main/java/stirling/software/common/util/CbrUtils.java
View File

@@ -129,7 +129,12 @@ public class CbrUtils {
new PDRectangle(pdImage.getWidth(), pdImage.getHeight()));
document.addPage(page);
try (PDPageContentStream contentStream =
new PDPageContentStream(document, page)) {
new PDPageContentStream(
document,
page,
PDPageContentStream.AppendMode.OVERWRITE,
true,
true)) {
contentStream.drawImage(pdImage, 0, 0);
}
} catch (IOException e) {

7
app/common/src/main/java/stirling/software/common/util/CbzUtils.java
View File

@@ -97,7 +97,12 @@ public class CbzUtils {
new PDRectangle(pdImage.getWidth(), pdImage.getHeight()));
document.addPage(page);
try (PDPageContentStream contentStream =
new PDPageContentStream(document, page)) {
new PDPageContentStream(
document,
page,
PDPageContentStream.AppendMode.OVERWRITE,
true,
true)) {
contentStream.drawImage(pdImage, 0, 0);
}
} catch (IOException e) {

2
app/common/src/main/java/stirling/software/common/util/ExceptionUtils.java
View File

@@ -41,7 +41,7 @@ import lombok.extern.slf4j.Slf4j;
* <pre>{@code
* // In service layer - create exception with ExceptionUtils
* try {
* PDDocument doc = PDDocument.load(file);
* PDDocument doc = Loader.loadPDF(file);
* } catch (IOException e) {
* throw ExceptionUtils.createPdfCorruptedException("during load", e);
* }

1
app/common/src/main/java/stirling/software/common/util/PdfToCbrUtils.java
View File

@@ -60,6 +60,7 @@ public class PdfToCbrUtils {
private static byte[] createCbrFromPdf(PDDocument document, int dpi) throws IOException {
PDFRenderer pdfRenderer = new PDFRenderer(document);
pdfRenderer.setSubsamplingAllowed(true); // Enable subsampling to reduce memory usage
Path tempDir = Files.createTempDirectory("stirling-pdf-cbr-");
List<Path> generatedImages = new ArrayList<>();

1
app/common/src/main/java/stirling/software/common/util/PdfToCbzUtils.java
View File

@@ -55,6 +55,7 @@ public class PdfToCbzUtils {
private static byte[] createCbzFromPdf(PDDocument document, int dpi) throws IOException {
PDFRenderer pdfRenderer = new PDFRenderer(document);
pdfRenderer.setSubsamplingAllowed(true); // Enable subsampling to reduce memory usage
try (ByteArrayOutputStream cbzOutputStream = new ByteArrayOutputStream();
ZipOutputStream zipOut = new ZipOutputStream(cbzOutputStream)) {

112
app/common/src/main/java/stirling/software/common/util/PdfUtils.java
View File

@@ -119,11 +119,11 @@ public class PdfUtils {
public boolean hasTextOnPage(PDPage page, String phrase) throws IOException {
PDFTextStripper textStripper = new PDFTextStripper();
PDDocument tempDoc = new PDDocument();
tempDoc.addPage(page);
String pageText = textStripper.getText(tempDoc);
tempDoc.close();
return pageText.contains(phrase);
try (PDDocument tempDoc = new PDDocument()) {
tempDoc.addPage(page);
String pageText = textStripper.getText(tempDoc);
return pageText.contains(phrase);
}
}
public byte[] convertFromPdf(
@@ -153,7 +153,8 @@ public class PdfUtils {
maxSafeDpi);
}
try (PDDocument document = pdfDocumentFactory.load(inputStream)) {
try (PDDocument document = pdfDocumentFactory.load(inputStream);
ByteArrayOutputStream baos = new ByteArrayOutputStream()) {
PDFRenderer pdfRenderer = new PDFRenderer(document);
pdfRenderer.setSubsamplingAllowed(true);
if (!includeAnnotations) {
@@ -161,9 +162,6 @@ public class PdfUtils {
}
int pageCount = document.getNumberOfPages();
// Create a ByteArrayOutputStream to save the image(s) to
ByteArrayOutputStream baos = new ByteArrayOutputStream();
if (singleImage) {
if ("tiff".equals(imageType.toLowerCase(Locale.ROOT))
|| "tif".equals(imageType.toLowerCase(Locale.ROOT))) {
@@ -400,55 +398,61 @@ public class PdfUtils {
*/
public PDDocument convertPdfToPdfImage(PDDocument document) throws IOException {
PDDocument imageDocument = new PDDocument();
PDFRenderer pdfRenderer = new PDFRenderer(document);
pdfRenderer.setSubsamplingAllowed(true);
for (int page = 0; page < document.getNumberOfPages(); ++page) {
final int pageIndex = page;
BufferedImage bim;
try {
PDFRenderer pdfRenderer = new PDFRenderer(document);
pdfRenderer.setSubsamplingAllowed(true);
for (int page = 0; page < document.getNumberOfPages(); ++page) {
final int pageIndex = page;
BufferedImage bim;
// Use global maximum DPI setting, fallback to 300 if not set
int renderDpi = 300; // Default fallback
ApplicationProperties properties =
ApplicationContextProvider.getBean(ApplicationProperties.class);
if (properties != null && properties.getSystem() != null) {
renderDpi = properties.getSystem().getMaxDPI();
}
final int dpi = renderDpi;
try {
bim =
ExceptionUtils.handleOomRendering(
pageIndex + 1,
dpi,
() ->
pdfRenderer.renderImageWithDPI(
pageIndex, dpi, ImageType.RGB));
} catch (IllegalArgumentException e) {
if (e.getMessage() != null
&& e.getMessage().contains("Maximum size of image exceeded")) {
throw ExceptionUtils.createIllegalArgumentException(
"error.pageTooBigFor300Dpi",
"PDF page {0} is too large to render at 300 DPI. The resulting image"
+ " would exceed Java's maximum array size. Please use a lower DPI"
+ " value for PDF-to-image conversion.",
pageIndex + 1);
// Use global maximum DPI setting, fallback to 300 if not set
int renderDpi = 300; // Default fallback
ApplicationProperties properties =
ApplicationContextProvider.getBean(ApplicationProperties.class);
if (properties != null && properties.getSystem() != null) {
renderDpi = properties.getSystem().getMaxDPI();
}
throw e;
final int dpi = renderDpi;
try {
bim =
ExceptionUtils.handleOomRendering(
pageIndex + 1,
dpi,
() ->
pdfRenderer.renderImageWithDPI(
pageIndex, dpi, ImageType.RGB));
} catch (IllegalArgumentException e) {
if (e.getMessage() != null
&& e.getMessage().contains("Maximum size of image exceeded")) {
throw ExceptionUtils.createIllegalArgumentException(
"error.pageTooBigFor300Dpi",
"PDF page {0} is too large to render at 300 DPI. The resulting image"
+ " would exceed Java's maximum array size. Please use a lower DPI"
+ " value for PDF-to-image conversion.",
pageIndex + 1);
}
throw e;
}
PDPage originalPage = document.getPage(page);
float width = originalPage.getMediaBox().getWidth();
float height = originalPage.getMediaBox().getHeight();
PDPage newPage = new PDPage(new PDRectangle(width, height));
imageDocument.addPage(newPage);
PDImageXObject pdImage = LosslessFactory.createFromImage(imageDocument, bim);
try (PDPageContentStream contentStream =
new PDPageContentStream(
imageDocument, newPage, AppendMode.APPEND, true, true)) {
contentStream.drawImage(pdImage, 0, 0, width, height);
}
bim.flush();
}
PDPage originalPage = document.getPage(page);
float width = originalPage.getMediaBox().getWidth();
float height = originalPage.getMediaBox().getHeight();
PDPage newPage = new PDPage(new PDRectangle(width, height));
imageDocument.addPage(newPage);
PDImageXObject pdImage = LosslessFactory.createFromImage(imageDocument, bim);
PDPageContentStream contentStream =
new PDPageContentStream(imageDocument, newPage, AppendMode.APPEND, true, true);
contentStream.drawImage(pdImage, 0, 0, width, height);
contentStream.close();
return imageDocument;
} catch (Exception e) {
throw e;
}
return imageDocument;
}
private BufferedImage prepareImageForPdfToImage(int maxWidth, int height, String imageType) {

1
app/common/src/main/java/stirling/software/common/util/WebResponseUtils.java
View File

@@ -69,7 +69,6 @@ public class WebResponseUtils {
// Open Byte Array and save document to it
ByteArrayOutputStream baos = new ByteArrayOutputStream();
document.save(baos);
document.close();
return baosToWebResponse(baos, docName);
}

7
app/common/src/main/java/stirling/software/common/util/misc/CustomColorReplaceStrategy.java
View File

@@ -146,13 +146,18 @@ public class CustomColorReplaceStrategy extends ReplaceAndInvertColorStrategy {
// Save the modified PDF to a ByteArrayOutputStream
ByteArrayOutputStream byteArrayOutputStream = new ByteArrayOutputStream();
document.save(byteArrayOutputStream);
document.close();
// Prepare the modified PDF for download
ByteArrayInputStream inputStream =
new ByteArrayInputStream(byteArrayOutputStream.toByteArray());
InputStreamResource resource = new InputStreamResource(inputStream);
return resource;
} finally {
try {
Files.deleteIfExists(file.toPath());
} catch (IOException e) {
log.warn("Failed to delete temporary file: {}", file.getAbsolutePath(), e);
}
}
}

38
app/common/src/main/java/stirling/software/common/util/misc/InvertFullColorStrategy.java
View File

@@ -7,6 +7,7 @@ import java.io.ByteArrayOutputStream;
import java.io.File;
import java.io.IOException;
import java.nio.file.Files;
import java.nio.file.Path;
import javax.imageio.ImageIO;
@@ -19,11 +20,14 @@ import org.apache.pdfbox.rendering.PDFRenderer;
import org.springframework.core.io.InputStreamResource;
import org.springframework.web.multipart.MultipartFile;
import lombok.extern.slf4j.Slf4j;
import stirling.software.common.model.ApplicationProperties;
import stirling.software.common.model.api.misc.ReplaceAndInvert;
import stirling.software.common.util.ApplicationContextProvider;
import stirling.software.common.util.ExceptionUtils;
@Slf4j
public class InvertFullColorStrategy extends ReplaceAndInvertColorStrategy {
public InvertFullColorStrategy(MultipartFile file, ReplaceAndInvert replaceAndInvert) {
@@ -43,6 +47,8 @@ public class InvertFullColorStrategy extends ReplaceAndInvertColorStrategy {
try (PDDocument document = Loader.loadPDF(tempFile.getFile())) {
// Render each page and invert colors
PDFRenderer pdfRenderer = new PDFRenderer(document);
pdfRenderer.setSubsamplingAllowed(
true); // Enable subsampling to reduce memory usage
for (int page = 0; page < document.getNumberOfPages(); page++) {
BufferedImage image;
@@ -73,12 +79,27 @@ public class InvertFullColorStrategy extends ReplaceAndInvertColorStrategy {
PDImageXObject pdImage =
PDImageXObject.createFromFileByContent(tempImageFile, document);
// Delete temp file immediately after loading into memory to prevent disk
// exhaustion
// The file content is now in the PDImageXObject, so the file is no longer
// needed
try {
Files.deleteIfExists(tempImageFile.toPath());
tempImageFile = null; // Mark as deleted to avoid double deletion
} catch (IOException e) {
log.warn(
"Failed to delete temporary image file: {}",
tempImageFile.getAbsolutePath(),
e);
}
try (PDPageContentStream contentStream =
new PDPageContentStream(
document,
pdPage,
PDPageContentStream.AppendMode.OVERWRITE,
true)) {
true,
true)) { // resetContext=true ensures clean graphics state
contentStream.drawImage(
pdImage,
0,
@@ -87,8 +108,16 @@ public class InvertFullColorStrategy extends ReplaceAndInvertColorStrategy {
pdPage.getMediaBox().getHeight());
}
} finally {
// Safety net: ensure temp file is deleted even if an exception occurred
if (tempImageFile != null && tempImageFile.exists()) {
Files.delete(tempImageFile.toPath());
try {
Files.deleteIfExists(tempImageFile.toPath());
} catch (IOException e) {
log.warn(
"Failed to delete temporary image file: {}",
tempImageFile.getAbsolutePath(),
e);
}
}
}
}
@@ -128,7 +157,10 @@ public class InvertFullColorStrategy extends ReplaceAndInvertColorStrategy {
// Helper method to convert BufferedImage to InputStream
private File convertToBufferedImageTpFile(BufferedImage image) throws IOException {
File file = File.createTempFile("image", ".png");
// Use Files.createTempFile instead of File.createTempFile for better security and modern
// Java practices
Path tempPath = Files.createTempFile("image", ".png");
File file = tempPath.toFile();
ImageIO.write(image, "png", file);
return file;
}

3
app/common/src/test/java/stirling/software/common/util/WebResponseUtilsTest.java
View File

@@ -92,8 +92,7 @@ public class WebResponseUtilsTest {
@Test
public void testPdfDocToWebResponse() {
try {
PDDocument document = new PDDocument();
try (PDDocument document = new PDDocument()) {
document.addPage(new org.apache.pdfbox.pdmodel.PDPage());
String docName = "sample.pdf";