Return pdf file

src/main/java/ch/dlmw/swisssignchallenge/controllers/SigningRequestDocumentController.java

@@ -1,6 +1,7 @@
 package ch.dlmw.swisssignchallenge.controllers;
 
 import ch.dlmw.swisssignchallenge.entities.SigningRequestDocument;
+import ch.dlmw.swisssignchallenge.services.PdfService;
 import ch.dlmw.swisssignchallenge.services.SigningRequestDocumentService;
 import com.fasterxml.jackson.databind.JsonNode;
 import com.fasterxml.jackson.databind.ObjectMapper;
@@ -9,6 +10,7 @@ import com.github.fge.jsonpatch.JsonPatchException;
 import lombok.AllArgsConstructor;
 import org.openapitools.api.SigningRequestDocumentApi;
 import org.openapitools.model.PatchOperation;
+import org.springframework.core.io.Resource;
 import org.springframework.http.ResponseEntity;
 import org.springframework.web.bind.annotation.RestController;
 
@@ -19,6 +21,7 @@ import java.util.List;
 @AllArgsConstructor
 public class SigningRequestDocumentController implements SigningRequestDocumentApi {
     private final SigningRequestDocumentService signingRequestDocumentService;
+    private final PdfService pdfService;
     private final ObjectMapper objectMapper;
 
     @Override
@@ -38,6 +41,13 @@ public class SigningRequestDocumentController implements SigningRequestDocumentA
         }
     }
 
+    @Override
+    public ResponseEntity<Resource> getSigningRequestDocumentData(String id) {
+        var document = signingRequestDocumentService.getSigningRequestDocument(id);
+
+        return ResponseEntity.ok(pdfService.getPdf(document.getName()));
+    }
+
     private <T> T applyPatch(List<PatchOperation> patchOperations, T object, Class<T> entityType) throws JsonPatchException, IOException {
         JsonNode patchNode = objectMapper.valueToTree(patchOperations);
         JsonPatch jsonPatch = JsonPatch.fromJson(patchNode);

src/main/java/ch/dlmw/swisssignchallenge/services/PdfService.java

@@ -0,0 +1,7 @@
+package ch.dlmw.swisssignchallenge.services;
+
+import org.springframework.core.io.Resource;
+
+public interface PdfService {
+    Resource getPdf(String name);
+}

src/main/java/ch/dlmw/swisssignchallenge/services/impl/PdfServiceImpl.java

@@ -0,0 +1,38 @@
+package ch.dlmw.swisssignchallenge.services.impl;
+
+import ch.dlmw.swisssignchallenge.services.PdfService;
+import lombok.AllArgsConstructor;
+import org.springframework.core.io.Resource;
+import org.springframework.core.io.UrlResource;
+import org.springframework.stereotype.Service;
+
+import java.net.MalformedURLException;
+import java.nio.file.Path;
+import java.nio.file.Paths;
+import java.util.NoSuchElementException;
+
+@Service
+@AllArgsConstructor
+public class PdfServiceImpl implements PdfService {
+    private static final String FILE_DIRECTORY = "/srv/pdfs/";
+
+    @Override
+    public Resource getPdf(String name) {
+        if (name.contains("..")) { // this is to avoid traversal attacks
+            throw new IllegalArgumentException("Invalid file name: " + name);
+        }
+
+        Path filePath = Paths.get(FILE_DIRECTORY).resolve(name).normalize();
+        Resource resource;
+        try {
+            resource = new UrlResource(filePath.toUri());
+        } catch (MalformedURLException e) {
+            throw new IllegalArgumentException("Invalid file name: " + name);
+        }
+        if (!resource.exists() || !resource.isReadable()) {
+            throw new NoSuchElementException("Couldn't find file: " + name);
+        }
+
+        return resource;
+    }
+}