add remove digital signature

src/main/java/stirling/software/SPDF/controller/api/security/RemoveCertSignController.java

@@ -0,0 +1,71 @@
+package stirling.software.SPDF.controller.api.security;
+
+import java.io.ByteArrayOutputStream;
+
+import org.apache.pdfbox.Loader;
+import org.apache.pdfbox.pdmodel.PDDocument;
+import org.apache.pdfbox.pdmodel.PDDocumentCatalog;
+import org.apache.pdfbox.pdmodel.interactive.form.PDAcroForm;
+import org.apache.pdfbox.pdmodel.interactive.form.PDSignatureField;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+import org.springframework.http.ResponseEntity;
+import org.springframework.web.bind.annotation.ModelAttribute;
+import org.springframework.web.bind.annotation.PostMapping;
+import org.springframework.web.bind.annotation.RequestMapping;
+import org.springframework.web.bind.annotation.RestController;
+import org.springframework.web.multipart.MultipartFile;
+
+import io.github.pixee.security.Filenames;
+import io.swagger.v3.oas.annotations.Operation;
+import io.swagger.v3.oas.annotations.tags.Tag;
+
+import stirling.software.SPDF.model.api.PDFFile;
+import stirling.software.SPDF.utils.WebResponseUtils;
+
+@RestController
+@RequestMapping("/api/v1/security")
+@Tag(name = "Security", description = "Security APIs")
+public class RemoveCertSignController {
+
+    private static final Logger logger = LoggerFactory.getLogger(RemoveCertSignController.class);
+
+    @PostMapping(consumes = "multipart/form-data", value = "/remove-cert-sign")
+    @Operation(
+            summary = "Remove digital signature from PDF",
+            description =
+                    "This endpoint accepts a PDF file and returns the PDF file without the digital signature. Input: PDF, Output: PDF")
+    public ResponseEntity<byte[]> removeCertSignPDF(@ModelAttribute PDFFile request)
+            throws Exception {
+        MultipartFile pdf = request.getFileInput();
+
+        // Convert MultipartFile to byte[]
+        byte[] pdfBytes = pdf.getBytes();
+
+        // Create a ByteArrayOutputStream to hold the resulting PDF
+        ByteArrayOutputStream baos = new ByteArrayOutputStream();
+
+        // Load the PDF document
+        PDDocument document = Loader.loadPDF(pdfBytes);
+
+        // Get the document catalog
+        PDDocumentCatalog catalog = document.getDocumentCatalog();
+
+        // Get the AcroForm
+        PDAcroForm acroForm = catalog.getAcroForm();
+        if (acroForm != null) {
+            // Remove signature fields
+            acroForm.getFields().removeIf(field -> field instanceof PDSignatureField);
+        }
+
+        // Save the modified document to the ByteArrayOutputStream
+        document.save(baos);
+        document.close();
+
+        // Return the modified PDF as a response
+        return WebResponseUtils.boasToWebResponse(
+                baos,
+                Filenames.toSimpleFileName(pdf.getOriginalFilename()).replaceFirst("[.][^.]+$", "")
+                        + "_unsigned.pdf");
+    }
+}