add stream wrapper

Author: Schmarvinius

cds-feature-attachments/src/main/java/com/sap/cds/feature/attachments/handler/applicationservice/helper/ModifyApplicationHandlerHelper.java

@@ -10,6 +10,7 @@
 import com.sap.cds.feature.attachments.generated.cds4j.sap.attachments.Attachments;
 import com.sap.cds.feature.attachments.handler.applicationservice.modifyevents.ModifyAttachmentEvent;
 import com.sap.cds.feature.attachments.handler.applicationservice.modifyevents.ModifyAttachmentEventFactory;
+import com.sap.cds.feature.attachments.handler.applicationservice.readhelper.CountingInputStream;
 import com.sap.cds.feature.attachments.handler.common.ApplicationHandlerHelper;
 import com.sap.cds.ql.cqn.Path;
 import com.sap.cds.reflect.CdsEntity;
@@ -23,30 +24,28 @@
 
 public final class ModifyApplicationHandlerHelper {
 
-  private static final Filter VALMAX_FILTER =
-      (path, element, type) ->
-          element.getName().contentEquals("content")
-              && element.findAnnotation("Validation.Maximum").isPresent();
+  private static final Filter VALMAX_FILTER = (path, element, type) -> element.getName().contentEquals("content")
+      && element.findAnnotation("Validation.Maximum").isPresent();
 
   /**
    * Handles attachments for entities.
    *
-   * @param entity the {@link CdsEntity entity} to handle attachments for
-   * @param data the given list of {@link CdsData data}
+   * @param entity              the {@link CdsEntity entity} to handle attachments
+   *                            for
+   * @param data                the given list of {@link CdsData data}
    * @param existingAttachments the given list of existing {@link CdsData data}
-   * @param eventFactory the {@link ModifyAttachmentEventFactory} to create the corresponding event
-   * @param eventContext the current {@link EventContext}
+   * @param eventFactory        the {@link ModifyAttachmentEventFactory} to create
+   *                            the corresponding event
+   * @param eventContext        the current {@link EventContext}
    */
   public static void handleAttachmentForEntities(
       CdsEntity entity,
       List<CdsData> data,
       List<Attachments> existingAttachments,
       ModifyAttachmentEventFactory eventFactory,
       EventContext eventContext) {
-    Converter converter =
-        (path, element, value) ->
-            handleAttachmentForEntity(
-                existingAttachments, eventFactory, eventContext, path, (InputStream) value);
+    Converter converter = (path, element, value) -> handleAttachmentForEntity(
+        existingAttachments, eventFactory, eventContext, path, (InputStream) value);
 
     CdsDataProcessor.create()
         .addConverter(ApplicationHandlerHelper.MEDIA_CONTENT_FILTER, converter)
@@ -56,11 +55,13 @@ public static void handleAttachmentForEntities(
   /**
    * Handles attachments for a single entity.
    *
-   * @param existingAttachments the list of existing {@link Attachments} to check against
-   * @param eventFactory the {@link ModifyAttachmentEventFactory} to create the corresponding event
-   * @param eventContext the current {@link EventContext}
-   * @param path the {@link Path} of the attachment
-   * @param content the content of the attachment
+   * @param existingAttachments the list of existing {@link Attachments} to check
+   *                            against
+   * @param eventFactory        the {@link ModifyAttachmentEventFactory} to create
+   *                            the corresponding event
+   * @param eventContext        the current {@link EventContext}
+   * @param path                the {@link Path} of the attachment
+   * @param content             the content of the attachment
    * @return the processed content as an {@link InputStream}
    */
   public static InputStream handleAttachmentForEntity(
@@ -74,28 +75,15 @@ public static InputStream handleAttachmentForEntity(
     Attachments attachment = getExistingAttachment(keys, existingAttachments);
     String contentId = (String) path.target().values().get(Attachments.CONTENT_ID);
     String contentLength = eventContext.getParameterInfo().getHeader("Content-Length");
-    String maxSizeStr = getValMaxValue(path.target().entity(), existingAttachments);
-
-    if (maxSizeStr != null && content != null) {
-      try {
-        long maxSize = FileSizeUtils.parseFileSizeToBytes(maxSizeStr);
-        if (contentLength != null && Long.parseLong(contentLength) > maxSize) {
-          throw new RuntimeException("File size exceeds the maximum allowed size of " + maxSizeStr);
-        }
-      } catch (ArithmeticException e) {
-        throw new ServiceException("Maximum file size value is too large", e);
-      } catch (IllegalArgumentException e) {
-        throw new ServiceException(ErrorStatuses.BAD_REQUEST, "Failed to process attachment size");
-      } catch (RuntimeException e) {
-        throw new ServiceException(ExtendedErrorStatuses.CONTENT_TOO_LARGE, "AttachmentSizeExceeded", maxSizeStr);
-      }
-    }
+    
+    InputStream wrappedContent = wrapWithCountingStream(content, path.target().entity(), existingAttachments,
+        contentLength);
 
     // for the current request find the event to process
-    ModifyAttachmentEvent eventToProcess = eventFactory.getEvent(content, contentId, attachment);
+    ModifyAttachmentEvent eventToProcess = eventFactory.getEvent(wrappedContent, contentId, attachment);
 
     // process the event
-    return eventToProcess.processEvent(path, content, attachment, eventContext);
+    return eventToProcess.processEvent(path, wrappedContent, attachment, eventContext);
   }
 
   private static String getValMaxValue(CdsEntity entity, List<? extends CdsData> data) {
@@ -120,6 +108,27 @@ private static Attachments getExistingAttachment(
         .orElse(Attachments.create());
   }
 
+  private static InputStream wrapWithCountingStream(
+      InputStream content, CdsEntity entity, List<? extends CdsData> data, String contentLength) {
+    String maxSizeStr = getValMaxValue(entity, data);
+
+    if (maxSizeStr != null && content != null) {
+      try {
+        long maxSize = FileSizeUtils.parseFileSizeToBytes(maxSizeStr);
+        // if (contentLength != null && Long.parseLong(contentLength) > maxSize) {
+        //   throw new RuntimeException();
+        // }
+        return new CountingInputStream(content, maxSize);
+      } catch (ArithmeticException e) {
+        throw new ServiceException("Maximum file size value is too large", e);
+      } catch (RuntimeException e) {
+        throw new ServiceException(
+            ExtendedErrorStatuses.CONTENT_TOO_LARGE, "AttachmentSizeExceeded", maxSizeStr);
+      }
+    }
+    return content;
+  }
+
   private ModifyApplicationHandlerHelper() {
     // avoid instantiation
   }

cds-feature-attachments/src/main/java/com/sap/cds/feature/attachments/handler/applicationservice/readhelper/CountingInputStream.java

@@ -0,0 +1,73 @@
+/*
+ * © 2026 SAP SE or an SAP affiliate company and cds-feature-attachments contributors.
+ */
+package com.sap.cds.feature.attachments.handler.applicationservice.readhelper;
+
+import com.sap.cds.feature.attachments.handler.applicationservice.helper.ExtendedErrorStatuses;
+import com.sap.cds.services.ServiceException;
+import java.io.IOException;
+import java.io.InputStream;
+
+public class CountingInputStream extends InputStream {
+
+    private final InputStream delegate;
+    private long byteCount = 0;
+    private long maxBytes;
+
+    public CountingInputStream(InputStream delegate, long maxBytes) {
+        this.delegate = delegate;
+        this.maxBytes = maxBytes;
+    }
+
+    @Override
+    public int read() throws IOException {
+        int b = delegate.read();
+        if (b != -1) {
+            checkLimit(1);
+        }
+        return b;
+    }
+
+    @Override
+    public int read(byte[] b) throws IOException {
+        int bytesRead = delegate.read(b);
+        if (bytesRead > 0) {
+            checkLimit(bytesRead);
+        }
+        return bytesRead;
+    }
+
+    @Override
+    public int read(byte[] b, int off, int len) throws IOException {
+        int bytesRead = delegate.read(b, off, len);
+        if (bytesRead > 0) {
+            checkLimit(bytesRead);
+        }
+        return bytesRead;
+    }
+
+    @Override
+    public long skip(long n) throws IOException {
+        long skipped = delegate.skip(n);
+        if (skipped > 0) {
+            checkLimit(skipped);
+        }
+        return skipped;
+    }
+
+    @Override
+    public void close() throws IOException {
+        if (delegate != null)
+            delegate.close();
+    }
+
+    private void checkLimit(long bytes) {
+        byteCount += bytes;
+        if (byteCount > maxBytes) {
+            throw new ServiceException(
+                    ExtendedErrorStatuses.CONTENT_TOO_LARGE,
+                    "AttachmentSizeExceeded",
+                    maxBytes);
+        }
+    }
+}