Feature/save signs (#2127)

* apply fix

* Fixes empty th:action

* Update build.gradle

* fix

* formatting

* Save signatures

* Fix code scanning alert no. 42: Uncontrolled data used in path expression

Co-authored-by: Copilot Autofix powered by AI <62310815+github-advanced-security[bot]@users.noreply.github.com>

* fix UserServiceInterface

* Merge branch 'feature/saveSigns' of
git@github.com:Stirling-Tools/Stirling-PDF.git into feature/saveSigns

* 0.31.0 bump and further csrf

* formatting

* preview name

* add

* sign doc

* Update translation files (#2128)

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---------

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Co-authored-by: Dimitrios Kaitantzidis <james_k23@hotmail.gr>
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Co-authored-by: a <a>
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src/main/java/stirling/software/SPDF/controller/web/SignatureController.java

@@ -0,0 +1,44 @@
+package stirling.software.SPDF.controller.web;
+
+import java.io.IOException;
+
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.http.HttpStatus;
+import org.springframework.http.MediaType;
+import org.springframework.http.ResponseEntity;
+import org.springframework.stereotype.Controller;
+import org.springframework.web.bind.annotation.GetMapping;
+import org.springframework.web.bind.annotation.PathVariable;
+import org.springframework.web.bind.annotation.RequestMapping;
+
+import stirling.software.SPDF.controller.api.pipeline.UserServiceInterface;
+import stirling.software.SPDF.service.SignatureService;
+
+@Controller
+@RequestMapping("/api/v1/general/")
+public class SignatureController {
+
+    @Autowired private SignatureService signatureService;
+
+    @Autowired(required = false)
+    private UserServiceInterface userService;
+
+    @GetMapping("/sign/{fileName}")
+    public ResponseEntity<byte[]> getSignature(@PathVariable(name = "fileName") String fileName)
+            throws IOException {
+        String username = "NON_SECURITY_USER";
+        if (userService != null) {
+            username = userService.getCurrentUsername();
+        }
+
+        // Verify access permission
+        if (!signatureService.hasAccessToFile(username, fileName)) {
+            return ResponseEntity.status(HttpStatus.FORBIDDEN).build();
+        }
+
+        byte[] imageBytes = signatureService.getSignatureBytes(username, fileName);
+        return ResponseEntity.ok()
+                .contentType(MediaType.IMAGE_JPEG) // Adjust based on file type
+                .body(imageBytes);
+    }
+}