1 files changed, 75 insertions, 0 deletions
diff --git a/src/main/java/at/gv/egiz/moazs/backend/MsgResponseBackend.java b/src/main/java/at/gv/egiz/moazs/backend/MsgResponseBackend.java
new file mode 100644
index 0000000..414c2dc
--- /dev/null
+++ b/src/main/java/at/gv/egiz/moazs/backend/MsgResponseBackend.java
@@ -0,0 +1,75 @@
+package at.gv.egiz.moazs.backend;
+
+import at.gv.egiz.moazs.MoaZSException;
+import at.gv.egiz.moazs.repository.DeliveryRepository;
+import at.gv.egiz.moazs.scheme.MsgResponse;
+import at.gv.egiz.moazs.service.MsgService;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.stereotype.Component;
+
+import java.util.concurrent.CompletableFuture;
+import java.util.function.Consumer;
+import java.util.function.Function;
+
+import static at.gv.egiz.moazs.MoaZSException.moaZSExceptionBuilder;
+import static java.lang.String.format;
+import static java.util.concurrent.CompletableFuture.supplyAsync;
+
+@Component
+public class MsgResponseBackend implements Consumer<String> {
+
+    private static final Logger log = LoggerFactory.getLogger(MsgService.class);
+
+    public static final String MOASP_SIGNATURE_INVALID_ERROR_MSG = "Signature of Msg Response " +
+            "with AppDeliveryID=%s is not valid.";
+
+    private final DeliveryRepository repository;
+    private final Consumer<byte[]> signatureVerifier;
+    private final Function<MsgResponse, CompletableFuture<Void>> sink;
+
+    @Autowired
+    public MsgResponseBackend(DeliveryRepository repository,
+                              Consumer<byte[]> signatureVerifier,
+                              Function<MsgResponse, CompletableFuture<Void>> sink) {
+        this.repository = repository;
+        this.signatureVerifier = signatureVerifier;
+        this.sink = sink;
+    }
+
+    /**
+     * Performs all {@code MsgResponse}'s Back-End Tasks, such as verifying
+     * its signature and archiving the response.
+     *
+     * @param responseID refers to MsgResponse Object.
+     */
+    @Override
+    public void accept(String responseID) {
+        supplyAsync(() -> verify(responseID)).thenAcceptAsync(sink::apply);
+    }
+
+    public MsgResponse verify(String responseID) {
+
+        var response = repository.retrieveResponse(responseID).get();
+        var builder = moaZSExceptionBuilder().withAllParametersInAnswer(response.getAnswer());
+
+        var binaryResponse = repository.retrieveBinaryResponse(responseID).get();
+
+        try {
+            signatureVerifier.accept(binaryResponse);
+            return response;
+        } catch (MoaZSException ex) {
+            log.error(ex.getMessage(), ex);
+            var wrappingEx = builder
+                    .withMessage(format(MOASP_SIGNATURE_INVALID_ERROR_MSG, response.getAppDeliveryID()))
+                    .withErrorCode(MoaZSException.ERROR_MOASP_SIGNATURE_INVALID)
+                    .withCause(ex)
+                    .build();
+
+            return response.generateError(wrappingEx);
+        }
+
+    }
+
+}