feat:(pdfa-conversion) Implement Strict PDF/A Mode with Verification (#5663)

# Description of Changes


This PR introduces a new "Strict Mode" for the PDF to PDF/A conversion
tool. When enabled, the application will use VeraPDF to verify that the
resulting file is perfectly compliant with the selected PDF/A standard.
If validation fails, the system will return a descriptive error instead
of a non-compliant file.



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- Any challenges encountered

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---

## Checklist

### General

- [ ] I have read the [Contribution
Guidelines](https://github.com/Stirling-Tools/Stirling-PDF/blob/main/CONTRIBUTING.md)
- [ ] 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)
- [ ] I have performed a self-review of my own code
- [ ] 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)

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

### Testing (if applicable)

- [ ] 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>

app/core/src/main/java/stirling/software/SPDF/controller/api/converters/ConvertPDFToPDFA.java

@@ -71,10 +71,12 @@ import org.apache.xmpbox.schema.PDFAIdentificationSchema;
 import org.apache.xmpbox.schema.XMPBasicSchema;
 import org.apache.xmpbox.xml.DomXmpParser;
 import org.apache.xmpbox.xml.XmpSerializer;
+import org.springframework.http.HttpStatus;
 import org.springframework.http.MediaType;
 import org.springframework.http.ResponseEntity;
 import org.springframework.web.bind.annotation.ModelAttribute;
 import org.springframework.web.multipart.MultipartFile;
+import org.springframework.web.server.ResponseStatusException;
 
 import io.github.pixee.security.Filenames;
 import io.swagger.v3.oas.annotations.Operation;
@@ -99,6 +101,7 @@ public class ConvertPDFToPDFA {
 
     private static final Pattern NON_PRINTABLE_ASCII = Pattern.compile("[^\\x20-\\x7E]");
     private final RuntimePathConfig runtimePathConfig;
+    private final stirling.software.SPDF.service.VeraPDFService veraPDFService;
 
     private static final String ICC_RESOURCE_PATH = "/icc/sRGB2014.icc";
     private static final int PDFA_COMPATIBILITY_POLICY = 1;
@@ -587,7 +590,8 @@ public class ConvertPDFToPDFA {
         if (isPdfX) {
             return handlePdfXConversion(inputFile, outputFormat);
         } else {
-            return handlePdfAConversion(inputFile, outputFormat);
+            return handlePdfAConversion(
+                    inputFile, outputFormat, request.getStrict() != null && request.getStrict());
         }
     }
 
@@ -1793,7 +1797,7 @@ public class ConvertPDFToPDFA {
     }
 
     private ResponseEntity<byte[]> handlePdfAConversion(
-            MultipartFile inputFile, String outputFormat) throws Exception {
+            MultipartFile inputFile, String outputFormat, boolean strict) throws Exception {
         PdfaProfile profile = PdfaProfile.fromRequest(outputFormat);
 
         // Get the original filename without extension
@@ -1822,6 +1826,10 @@ public class ConvertPDFToPDFA {
 
                     validateAndWarnPdfA(converted, profile, "Ghostscript");
 
+                    if (strict) {
+                        verifyStrictCompliance(converted);
+                    }
+
                     return WebResponseUtils.bytesToWebResponse(
                             converted, outputFilename, MediaType.APPLICATION_PDF);
                 } catch (IOException | InterruptedException e) {
@@ -1839,14 +1847,42 @@ public class ConvertPDFToPDFA {
             // Validate with PDFBox preflight and warn if issues found
             validateAndWarnPdfA(converted, profile, "PDFBox/LibreOffice");
 
+            if (strict) {
+                verifyStrictCompliance(converted);
+            }
+
             return WebResponseUtils.bytesToWebResponse(
                     converted, outputFilename, MediaType.APPLICATION_PDF);
-
         } finally {
             deleteQuietly(workingDir);
         }
     }
 
+    private void verifyStrictCompliance(byte[] pdfBytes) throws IOException {
+        try (InputStream is = new ByteArrayInputStream(pdfBytes)) {
+            List<stirling.software.SPDF.model.api.security.PDFVerificationResult> results =
+                    veraPDFService.validatePDF(is);
+            boolean isCompliant = results.stream().anyMatch(result -> result.isCompliant());
+            if (!isCompliant) {
+                String details =
+                        results.stream()
+                                .map(r -> r.getStandard() + ": " + r.getComplianceSummary())
+                                .collect(Collectors.joining("; "));
+                throw new ResponseStatusException(
+                        HttpStatus.BAD_REQUEST,
+                        "Strict PDF/A mode enabled: Conversion is not perfectly compliant. Details: "
+                                + details);
+            }
+        } catch (Exception e) {
+            if (e instanceof ResponseStatusException) {
+                throw (ResponseStatusException) e;
+            }
+            log.error("Error during strict PDF/A verification", e);
+            throw new ResponseStatusException(
+                    HttpStatus.INTERNAL_SERVER_ERROR, "Error during strict PDF/A verification");
+        }
+    }
+
     private Path sanitizePdfWithPdfBox(Path inputPdf, boolean addWhiteBackground) {
         try {
             Path sanitizedPath =

app/core/src/main/java/stirling/software/SPDF/model/api/converters/PdfToPdfARequest.java

@@ -16,4 +16,9 @@ public class PdfToPdfARequest extends PDFFile {
             requiredMode = Schema.RequiredMode.REQUIRED,
             allowableValues = {"pdfa", "pdfa-1", "pdfa-2", "pdfa-2b", "pdfa-3", "pdfa-3b", "pdfx"})
     private String outputFormat;
+
+    @Schema(
+            description =
+                    "If true, the conversion will fail if the output is not perfectly compliant")
+    private Boolean strict = false;
 }

frontend/public/locales/en-GB/translation.toml

@@ -1303,6 +1303,8 @@ outputFormat = "Output Format"
 pdfaNote = "PDF/A-1b is more compatible, PDF/A-2b supports more features, PDF/A-3b supports embedded files."
 pdfaFormat = "PDF/A Format"
 pdfaDigitalSignatureWarning = "The PDF contains a digital signature. This will be removed in the next step."
+strictMode = "Strict Mode"
+strictModeDesc = "Error if conversion is not perfect (uses VeraPDF verification)"
 pdfxDigitalSignatureWarning = "The PDF contains a digital signature. This will be removed in the next step."
 pdfxDescription = "PDF/X is an ISO standard PDF subset for reliable printing and graphics exchange."
 fileFormat = "File Format"

frontend/src/core/components/tools/convert/ConvertSettings.tsx

@@ -146,7 +146,8 @@ const ConvertSettings = ({
       includeAllRecipients: false,
     });
     onParameterChange('pdfaOptions', {
-      outputFormat: 'pdfa-1',
+      outputFormat: 'pdfa-2b',
+      strict: false,
     });
     onParameterChange('pdfxOptions', {
       outputFormat: 'pdfx',
@@ -234,7 +235,8 @@ const ConvertSettings = ({
       includeAllRecipients: false,
     });
     onParameterChange('pdfaOptions', {
-      outputFormat: 'pdfa-1',
+      outputFormat: 'pdfa-2b',
+      strict: false,
     });
     onParameterChange('pdfxOptions', {
       outputFormat: 'pdfx',

frontend/src/core/components/tools/convert/ConvertToPdfaSettings.tsx

@@ -1,4 +1,4 @@
-import { Stack, Text, Select, Alert } from '@mantine/core';
+import { Stack, Text, Select, Alert, Checkbox } from '@mantine/core';
 import { useTranslation } from 'react-i18next';
 import { ConvertParameters } from '@app/hooks/tools/convert/useConvertParameters';
 import { usePdfSignatureDetection } from '@app/hooks/usePdfSignatureDetection';
@@ -23,8 +23,8 @@ const ConvertToPdfaSettings = ({
 
   const pdfaFormatOptions = [
     { value: 'pdfa-1', label: 'PDF/A-1b' },
-    { value: 'pdfa', label: 'PDF/A-2b' },
-    { value: 'pdfa-3', label: 'PDF/A-3b' }
+    { value: 'pdfa-2b', label: 'PDF/A-2b' },
+    { value: 'pdfa-3b', label: 'PDF/A-3b' }
   ];
 
   return (
@@ -45,7 +45,7 @@ const ConvertToPdfaSettings = ({
           value={parameters.pdfaOptions.outputFormat}
           onChange={(value) => onParameterChange('pdfaOptions', {
             ...parameters.pdfaOptions,
-            outputFormat: value || 'pdfa-1'
+            outputFormat: value || 'pdfa-2b'
           })}
           data={pdfaFormatOptions}
           disabled={disabled || isChecking}
@@ -56,6 +56,17 @@ const ConvertToPdfaSettings = ({
           {t("convert.pdfaNote", "PDF/A-1b is more compatible, PDF/A-2b supports more features, PDF/A-3b supports embedded files.")}
         </Text>
       </Stack>
+
+      <Checkbox
+        label={t("convert.strictMode", "Strict Mode")}
+        description={t("convert.strictModeDesc", "Error if conversion is not perfect (uses VeraPDF verification)")}
+        checked={parameters.pdfaOptions.strict}
+        onChange={(event) => onParameterChange('pdfaOptions', {
+          ...parameters.pdfaOptions,
+          strict: event.currentTarget.checked
+        })}
+        disabled={disabled || isChecking}
+      />
     </Stack>
   );
 };

frontend/src/core/hooks/tools/automate/useSuggestedAutomations.ts

@@ -48,7 +48,8 @@ export function useSuggestedAutomations(): SuggestedAutomation[] {
               fromExtension: 'pdf',
               toExtension: 'pdfa',
               pdfaOptions: {
-                outputFormat: 'pdfa-1',
+                outputFormat: 'pdfa-2b',
+                strict: false,
               }
             }
           },

frontend/src/core/hooks/tools/convert/useConvertOperation.ts

@@ -79,6 +79,7 @@ export const buildConvertFormData = (parameters: ConvertParameters, selectedFile
     formData.append("includeAllRecipients", emailOptions.includeAllRecipients.toString());
   } else if (fromExtension === 'pdf' && toExtension === 'pdfa') {
     formData.append("outputFormat", pdfaOptions.outputFormat);
+    formData.append("strict", String(!!pdfaOptions.strict));
   } else if (fromExtension === 'pdf' && toExtension === 'pdfx') {
     // Use PDF/A endpoint with PDF/X format parameter
     formData.append("outputFormat", pdfxOptions?.outputFormat || 'pdfx');

frontend/src/core/hooks/tools/convert/useConvertParameters.test.ts

@@ -24,7 +24,7 @@ describe('useConvertParameters', () => {
       expect(result.current.parameters.emailOptions.maxAttachmentSizeMB).toBe(10);
       expect(result.current.parameters.emailOptions.downloadHtml).toBe(false);
       expect(result.current.parameters.emailOptions.includeAllRecipients).toBe(false);
-      expect(result.current.parameters.pdfaOptions.outputFormat).toBe('pdfa-1');
+      expect(result.current.parameters.pdfaOptions.outputFormat).toBe('pdfa-2b');
     });
 
     test('should update individual parameters', () => {
@@ -95,7 +95,8 @@ describe('useConvertParameters', () => {
 
       act(() => {
         result.current.updateParameter('pdfaOptions', {
-          outputFormat: 'pdfa'
+          outputFormat: 'pdfa',
+          strict: false
         });
       });
 

frontend/src/core/hooks/tools/convert/useConvertParameters.ts

@@ -35,6 +35,7 @@ export interface ConvertParameters extends BaseParameters {
   };
   pdfaOptions: {
     outputFormat: string;
+    strict?: boolean;
   };
   pdfxOptions: {
     outputFormat: string;
@@ -93,7 +94,8 @@ export const defaultParameters: ConvertParameters = {
     includeAllRecipients: false,
   },
   pdfaOptions: {
-    outputFormat: 'pdfa-1',
+    outputFormat: 'pdfa-2b',
+    strict: false,
   },
   pdfxOptions: {
     outputFormat: 'pdfx',

frontend/src/core/tests/convert/ConvertIntegration.test.tsx

@@ -105,7 +105,7 @@ describe('Convert Tool Integration Tests', () => {
   beforeEach(() => {
     vi.clearAllMocks();
     // Setup default apiClient mock
-    mockedApiClient.post = vi.fn();
+    mockedApiClient.post = vi.fn() as any;
   });
 
   afterEach(() => {
@@ -150,7 +150,8 @@ describe('Convert Tool Integration Tests', () => {
           includeAllRecipients: false
         },
         pdfaOptions: {
-          outputFormat: ''
+          outputFormat: '',
+          strict: false
         },
         pdfxOptions: {
           outputFormat: 'pdfx'
@@ -232,7 +233,8 @@ describe('Convert Tool Integration Tests', () => {
           includeAllRecipients: false
         },
         pdfaOptions: {
-          outputFormat: ''
+          outputFormat: '',
+          strict: false
         },
         pdfxOptions: {
           outputFormat: 'pdfx'
@@ -292,7 +294,8 @@ describe('Convert Tool Integration Tests', () => {
           includeAllRecipients: false
         },
         pdfaOptions: {
-          outputFormat: ''
+          outputFormat: '',
+          strict: false
         },
         pdfxOptions: {
           outputFormat: 'pdfx'
@@ -361,7 +364,8 @@ describe('Convert Tool Integration Tests', () => {
           includeAllRecipients: false
         },
         pdfaOptions: {
-          outputFormat: ''
+          outputFormat: '',
+          strict: false
         },
         pdfxOptions: {
           outputFormat: 'pdfx'
@@ -434,7 +438,8 @@ describe('Convert Tool Integration Tests', () => {
           includeAllRecipients: false
         },
         pdfaOptions: {
-          outputFormat: ''
+          outputFormat: '',
+          strict: false
         },
         pdfxOptions: {
           outputFormat: 'pdfx'
@@ -505,7 +510,8 @@ describe('Convert Tool Integration Tests', () => {
           includeAllRecipients: false
         },
         pdfaOptions: {
-          outputFormat: ''
+          outputFormat: '',
+          strict: false
         },
         pdfxOptions: {
           outputFormat: 'pdfx'
@@ -572,7 +578,8 @@ describe('Convert Tool Integration Tests', () => {
           includeAllRecipients: false
         },
         pdfaOptions: {
-          outputFormat: ''
+          outputFormat: '',
+          strict: false
         },
         pdfxOptions: {
           outputFormat: 'pdfx'
@@ -636,7 +643,8 @@ describe('Convert Tool Integration Tests', () => {
           includeAllRecipients: false
         },
         pdfaOptions: {
-          outputFormat: ''
+          outputFormat: '',
+          strict: false
         },
         pdfxOptions: {
           outputFormat: 'pdfx'
@@ -702,7 +710,8 @@ describe('Convert Tool Integration Tests', () => {
           includeAllRecipients: false
         },
         pdfaOptions: {
-          outputFormat: ''
+          outputFormat: '',
+          strict: false
         },
         pdfxOptions: {
           outputFormat: 'pdfx'
@@ -765,7 +774,8 @@ describe('Convert Tool Integration Tests', () => {
           includeAllRecipients: false
         },
         pdfaOptions: {
-          outputFormat: ''
+          outputFormat: '',
+          strict: false
         },
         pdfxOptions: {
           outputFormat: 'pdfx'
@@ -834,7 +844,8 @@ describe('Convert Tool Integration Tests', () => {
           includeAllRecipients: false
         },
         pdfaOptions: {
-          outputFormat: ''
+          outputFormat: '',
+          strict: false
         },
         pdfxOptions: {
           outputFormat: 'pdfx'
@@ -902,7 +913,8 @@ describe('Convert Tool Integration Tests', () => {
           includeAllRecipients: false
         },
         pdfaOptions: {
-          outputFormat: ''
+          outputFormat: '',
+          strict: false
         },
         pdfxOptions: {
           outputFormat: 'pdfx'

frontend/src/core/tests/convert/ConvertSmartDetectionIntegration.test.tsx

@@ -396,7 +396,8 @@ describe('Convert Tool - Smart Detection Integration Tests', () => {
         paramsResult.current.updateParameter('fromExtension', 'pdf');
         paramsResult.current.updateParameter('toExtension', 'pdfa');
         paramsResult.current.updateParameter('pdfaOptions', {
-          outputFormat: 'pdfa'
+          outputFormat: 'pdfa',
+          strict: false
         });
       });
 
@@ -409,6 +410,7 @@ describe('Convert Tool - Smart Detection Integration Tests', () => {
 
       const formData = (mockedApiClient.post as Mock).mock.calls[0][1] as FormData;
       expect(formData.get('outputFormat')).toBe('pdfa');
+      expect(formData.get('strict')).toBe('false');
       expect(mockedApiClient.post).toHaveBeenCalledWith('/api/v1/convert/pdf/pdfa', expect.any(FormData), {
         responseType: 'blob'
       });