Enforce acceptable media types on update and draft patch

cds-feature-attachments/src/main/java/com/sap/cds/feature/attachments/configuration/Registration.java

@@ -156,8 +156,7 @@ public void eventHandlers(CdsRuntimeConfigurer configurer) {
     boolean hasApplicationServices =
         serviceCatalog.getServices(ApplicationService.class).findFirst().isPresent();
     if (hasApplicationServices) {
-      configurer.eventHandler(
-          new CreateAttachmentsHandler(eventFactory, storage, defaultMaxSize, runtime));
+      configurer.eventHandler(new CreateAttachmentsHandler(eventFactory, storage, defaultMaxSize));
       configurer.eventHandler(
           new UpdateAttachmentsHandler(
               eventFactory, attachmentsReader, outboxedAttachmentService, storage, defaultMaxSize));

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

@@ -23,7 +23,6 @@
 import com.sap.cds.services.handler.annotations.HandlerOrder;
 import com.sap.cds.services.handler.annotations.On;
 import com.sap.cds.services.handler.annotations.ServiceName;
-import com.sap.cds.services.runtime.CdsRuntime;
 import com.sap.cds.services.utils.OrderConstants;
 import java.util.ArrayList;
 import java.util.List;
@@ -42,17 +41,14 @@ public class CreateAttachmentsHandler implements EventHandler {
   private final ModifyAttachmentEventFactory eventFactory;
   private final ThreadDataStorageReader storageReader;
   private final String defaultMaxSize;
-  private final CdsRuntime cdsRuntime;
 
   public CreateAttachmentsHandler(
       ModifyAttachmentEventFactory eventFactory,
       ThreadDataStorageReader storageReader,
-      String defaultMaxSize,
-      CdsRuntime cdsRuntime) {
+      String defaultMaxSize) {
     this.eventFactory = eventFactory;
     this.storageReader = storageReader;
     this.defaultMaxSize = defaultMaxSize;
-    this.cdsRuntime = cdsRuntime;
   }
 
   @Before
@@ -69,7 +65,7 @@ void processBeforeForDraft(CdsCreateEventContext context, List<CdsData> data) {
   @HandlerOrder(HandlerOrder.BEFORE)
   void processBeforeForMetadata(EventContext context, List<CdsData> data) {
     CdsEntity target = context.getTarget();
-    AttachmentValidationHelper.validateMediaAttachments(target, data, cdsRuntime);
+    AttachmentValidationHelper.validateMediaAttachments(target, data, context.getModel());
   }
 
   @Before

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

@@ -8,6 +8,7 @@
 import com.sap.cds.feature.attachments.handler.applicationservice.helper.ModifyApplicationHandlerHelper;
 import com.sap.cds.feature.attachments.handler.applicationservice.helper.ReadonlyDataContextEnhancer;
 import com.sap.cds.feature.attachments.handler.applicationservice.helper.ThreadDataStorageReader;
+import com.sap.cds.feature.attachments.handler.applicationservice.helper.mimeTypeValidation.AttachmentValidationHelper;
 import com.sap.cds.feature.attachments.handler.applicationservice.modifyevents.ModifyAttachmentEventFactory;
 import com.sap.cds.feature.attachments.handler.common.ApplicationHandlerHelper;
 import com.sap.cds.feature.attachments.handler.common.AttachmentsReader;
@@ -68,6 +69,16 @@ void processBeforeForDraft(CdsUpdateEventContext context, List<CdsData> data) {
         context.getTarget(), data, storageReader.get());
   }
 
+  @Before
+  @HandlerOrder(HandlerOrder.BEFORE)
+  void processBeforeForMetadata(CdsUpdateEventContext context, List<CdsData> data) {
+    // Enforce @Core.AcceptableMediaTypes on updates as well, so replacement content or a
+    // metadata-only change (e.g. mimeType/fileName) cannot bypass the media type policy that is
+    // applied on create.
+    AttachmentValidationHelper.validateMediaAttachments(
+        context.getTarget(), data, context.getModel());
+  }
+
   @Before
   @HandlerOrder(HandlerOrder.LATE)
   void processBefore(CdsUpdateEventContext context, List<CdsData> data) {

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

@@ -10,7 +10,6 @@
 import com.sap.cds.reflect.CdsModel;
 import com.sap.cds.services.ErrorStatuses;
 import com.sap.cds.services.ServiceException;
-import com.sap.cds.services.runtime.CdsRuntime;
 import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
@@ -29,14 +28,14 @@ static void setCascader(AssociationCascader testCascader) {
    *
    * @param entity the {@link CdsEntity entity} type of the given data
    * @param data the list of {@link CdsData} to process
+   * @param cdsModel the (tenant-specific) {@link CdsModel} to resolve media entities against
    * @throws ServiceException if the media type of the attachment is not acceptable
    */
   public static void validateMediaAttachments(
-      CdsEntity entity, List<CdsData> data, CdsRuntime cdsRuntime) {
+      CdsEntity entity, List<? extends CdsData> data, CdsModel cdsModel) {
     if (entity == null) {
       return;
     }
-    CdsModel cdsModel = cdsRuntime.getCdsModel();
 
     List<String> mediaEntityNames =
         ApplicationHandlerHelper.isMediaEntity(entity)

cds-feature-attachments/src/main/java/com/sap/cds/feature/attachments/handler/draftservice/DraftPatchAttachmentsHandler.java

@@ -9,6 +9,7 @@
 import com.sap.cds.Result;
 import com.sap.cds.feature.attachments.generated.cds4j.sap.attachments.Attachments;
 import com.sap.cds.feature.attachments.handler.applicationservice.helper.ModifyApplicationHandlerHelper;
+import com.sap.cds.feature.attachments.handler.applicationservice.helper.mimeTypeValidation.AttachmentValidationHelper;
 import com.sap.cds.feature.attachments.handler.applicationservice.modifyevents.ModifyAttachmentEventFactory;
 import com.sap.cds.feature.attachments.handler.common.ApplicationHandlerHelper;
 import com.sap.cds.ql.Select;
@@ -55,6 +56,11 @@ void processBeforeDraftPatch(DraftPatchEventContext context, List<? extends CdsD
     logger.debug(
         "Processing before {} event for entity {}", context.getEvent(), context.getTarget());
 
+    // Enforce @Core.AcceptableMediaTypes on draft patches as well, so replacement content or
+    // metadata cannot bypass the media type policy that is applied on create/activate.
+    AttachmentValidationHelper.validateMediaAttachments(
+        context.getTarget(), data, context.getModel());
+
     Converter converter =
         (path, element, value) -> {
           CdsEntity draftEntity = DraftUtils.getDraftEntity(path.target().entity());

cds-feature-attachments/src/test/java/com/sap/cds/feature/attachments/handler/applicationservice/CreateAttachmentsHandlerTest.java

@@ -34,6 +34,7 @@
 import com.sap.cds.feature.attachments.handler.applicationservice.readhelper.CountingInputStream;
 import com.sap.cds.feature.attachments.handler.helper.RuntimeHelper;
 import com.sap.cds.reflect.CdsEntity;
+import com.sap.cds.reflect.CdsModel;
 import com.sap.cds.services.ErrorStatuses;
 import com.sap.cds.services.EventContext;
 import com.sap.cds.services.ServiceException;
@@ -75,10 +76,7 @@ void setup() {
     storageReader = mock(ThreadDataStorageReader.class);
     cut =
         new CreateAttachmentsHandler(
-            eventFactory,
-            storageReader,
-            ModifyApplicationHandlerHelper.DEFAULT_SIZE_WITH_SCANNER,
-            runtime);
+            eventFactory, storageReader, ModifyApplicationHandlerHelper.DEFAULT_SIZE_WITH_SCANNER);
 
     createContext = mock(CdsCreateEventContext.class);
     event = mock(ModifyAttachmentEvent.class);
@@ -355,19 +353,20 @@ void processBeforeForMetadata_executesValidation() {
     EventContext context = mock(EventContext.class);
     CdsEntity entity = mock(CdsEntity.class);
     List<CdsData> data = List.of(mock(CdsData.class));
+    CdsModel model = runtime.getCdsModel();
     when(context.getTarget()).thenReturn(entity);
+    when(context.getModel()).thenReturn(model);
 
     try (MockedStatic<AttachmentValidationHelper> helper =
         mockStatic(AttachmentValidationHelper.class)) {
       helper
-          .when(() -> AttachmentValidationHelper.validateMediaAttachments(entity, data, runtime))
+          .when(() -> AttachmentValidationHelper.validateMediaAttachments(entity, data, model))
           .thenAnswer(invocation -> null);
       // when
-      new CreateAttachmentsHandler(eventFactory, storageReader, "400MB", runtime)
+      new CreateAttachmentsHandler(eventFactory, storageReader, "400MB")
           .processBeforeForMetadata(context, data);
       // then
-      helper.verify(
-          () -> AttachmentValidationHelper.validateMediaAttachments(entity, data, runtime));
+      helper.verify(() -> AttachmentValidationHelper.validateMediaAttachments(entity, data, model));
     }
   }
 

cds-feature-attachments/src/test/java/com/sap/cds/feature/attachments/handler/applicationservice/helper/mimeTypeValidation/AttachmentValidationHelperTest.java

@@ -17,7 +17,6 @@
 import com.sap.cds.reflect.CdsEntity;
 import com.sap.cds.reflect.CdsModel;
 import com.sap.cds.services.ServiceException;
-import com.sap.cds.services.runtime.CdsRuntime;
 import java.util.List;
 import java.util.Map;
 import java.util.Optional;
@@ -47,23 +46,21 @@ void doesNothing_whenEntityNotFoundInModel() {
     CdsModel model = mock(CdsModel.class);
     when(model.findEntity("Entity")).thenReturn(Optional.empty());
 
-    CdsRuntime runtime = mockRuntime(model);
-
     try (MockedStatic<ApplicationHandlerHelper> helper =
         mockStatic(ApplicationHandlerHelper.class)) {
       helper.when(() -> ApplicationHandlerHelper.isMediaEntity(entity)).thenReturn(false);
 
       setupMockCascader(entity, model, false);
 
       assertDoesNotThrow(
-          () -> AttachmentValidationHelper.validateMediaAttachments(entity, List.of(), runtime));
+          () -> AttachmentValidationHelper.validateMediaAttachments(entity, List.of(), model));
     }
   }
 
   @Test
   void doesNothing_whenNoEntityHasAcceptableMediaTypesAnnotation() {
     CdsEntity entity = mockEntity("Entity");
-    CdsRuntime runtime = mockRuntime(entity);
+    CdsModel model = mockModel(entity);
 
     try (MockedStatic<ApplicationHandlerHelper> helper =
             mockStatic(ApplicationHandlerHelper.class);
@@ -83,7 +80,7 @@ void doesNothing_whenNoEntityHasAcceptableMediaTypesAnnotation() {
 
       // Verify that AttachmentDataExtractor is never called (early return)
       assertDoesNotThrow(
-          () -> AttachmentValidationHelper.validateMediaAttachments(entity, List.of(), runtime));
+          () -> AttachmentValidationHelper.validateMediaAttachments(entity, List.of(), model));
 
       extractor.verifyNoInteractions();
     }
@@ -100,7 +97,7 @@ void doesNotThrow_whenNoFiles() {
         MockedStatic<MediaTypeResolver> resolver = mockStatic(MediaTypeResolver.class);
         MockedStatic<AttachmentDataExtractor> extractor =
             mockStatic(AttachmentDataExtractor.class)) {
-      CdsRuntime runtime = mockRuntime(entity);
+      CdsModel model = mockModel(entity);
       helper.when(() -> ApplicationHandlerHelper.isMediaEntity(entity)).thenReturn(true);
 
       resolver
@@ -116,7 +113,7 @@ void doesNotThrow_whenNoFiles() {
           .thenReturn(null);
 
       assertDoesNotThrow(
-          () -> AttachmentValidationHelper.validateMediaAttachments(entity, List.of(), runtime));
+          () -> AttachmentValidationHelper.validateMediaAttachments(entity, List.of(), model));
     }
   }
 
@@ -125,7 +122,7 @@ void doesNotThrow_whenNoFiles() {
   void doesNotThrow_whenFilesAreValid(boolean isMediaEntity) {
 
     CdsEntity entity = mockEntity("Entity");
-    CdsRuntime runtime = mockRuntime(entity);
+    CdsModel model = mockModel(entity);
 
     Map<String, List<String>> allowed = Map.of(ATTACHMENTS_ENTITY, List.of("image/png"));
     Map<String, Set<String>> files = Map.of(ATTACHMENTS_ENTITY, Set.of("file.png"));
@@ -137,7 +134,7 @@ void doesNotThrow_whenFilesAreValid(boolean isMediaEntity) {
             mockStatic(AttachmentDataExtractor.class)) {
 
       helper.when(() -> ApplicationHandlerHelper.isMediaEntity(entity)).thenReturn(isMediaEntity);
-      setupMockCascader(entity, runtime.getCdsModel(), !isMediaEntity);
+      setupMockCascader(entity, model, !isMediaEntity);
 
       resolver
           .when(
@@ -152,7 +149,7 @@ void doesNotThrow_whenFilesAreValid(boolean isMediaEntity) {
           .thenReturn(files);
 
       assertDoesNotThrow(
-          () -> AttachmentValidationHelper.validateMediaAttachments(entity, List.of(), runtime));
+          () -> AttachmentValidationHelper.validateMediaAttachments(entity, List.of(), model));
     }
   }
 
@@ -168,7 +165,7 @@ private static Stream<Arguments> validFileScenarios() {
   void throwsException_whenFilesAreInvalid(boolean isMediaEntity) {
 
     CdsEntity entity = mockEntity("Entity");
-    CdsRuntime runtime = mockRuntime(entity);
+    CdsModel model = mockModel(entity);
 
     Map<String, List<String>> allowed = Map.of(ATTACHMENTS_ENTITY, List.of("image/png"));
     Map<String, Set<String>> files = Map.of(ATTACHMENTS_ENTITY, Set.of("file.txt"));
@@ -180,7 +177,7 @@ void throwsException_whenFilesAreInvalid(boolean isMediaEntity) {
             mockStatic(AttachmentDataExtractor.class)) {
 
       helper.when(() -> ApplicationHandlerHelper.isMediaEntity(entity)).thenReturn(isMediaEntity);
-      setupMockCascader(entity, runtime.getCdsModel(), !isMediaEntity);
+      setupMockCascader(entity, model, !isMediaEntity);
 
       resolver
           .when(
@@ -197,8 +194,7 @@ void throwsException_whenFilesAreInvalid(boolean isMediaEntity) {
       ServiceException ex =
           assertThrows(
               ServiceException.class,
-              () ->
-                  AttachmentValidationHelper.validateMediaAttachments(entity, List.of(), runtime));
+              () -> AttachmentValidationHelper.validateMediaAttachments(entity, List.of(), model));
 
       assertTrue(ex.getMessage().contains("Unsupported file types detected"));
     }
@@ -215,20 +211,10 @@ private void setupMockCascader(CdsEntity entity, CdsModel model, boolean hasAtta
     AttachmentValidationHelper.setCascader(cascader);
   }
 
-  private CdsRuntime mockRuntime(CdsEntity entity) {
+  private CdsModel mockModel(CdsEntity entity) {
     CdsModel model = mock(CdsModel.class);
     when(model.findEntity(entity.getQualifiedName())).thenReturn(Optional.of(entity));
-
-    CdsRuntime runtime = mock(CdsRuntime.class);
-    when(runtime.getCdsModel()).thenReturn(model);
-
-    return runtime;
-  }
-
-  private CdsRuntime mockRuntime(CdsModel model) {
-    CdsRuntime runtime = mock(CdsRuntime.class);
-    when(runtime.getCdsModel()).thenReturn(model);
-    return runtime;
+    return model;
   }
 
   private CdsEntity mockEntity(String name) {

cds-feature-attachments/src/test/java/com/sap/cds/feature/attachments/handler/draftservice/DraftPatchAttachmentsHandlerTest.java

@@ -192,5 +192,6 @@ private void getEntityAndMockContext(String cdsName) {
 
   private void mockTargetInUpdateContext(CdsEntity serviceEntity) {
     when(eventContext.getTarget()).thenReturn(serviceEntity);
+    when(eventContext.getModel()).thenReturn(runtime.getCdsModel());
   }
 }

integration-tests/generic/src/test/java/com/sap/cds/feature/attachments/integrationtests/draftservice/MediaValidatedAttachmentsDraftTest.java

@@ -22,6 +22,7 @@
 import org.junit.jupiter.params.provider.CsvSource;
 import org.springframework.http.MediaType;
 import org.springframework.test.context.ActiveProfiles;
+import org.springframework.test.web.servlet.MvcResult;
 
 @ActiveProfiles(Profiles.TEST_HANDLER_DISABLED)
 public class MediaValidatedAttachmentsDraftTest extends DraftOdataRequestValidationBase {
@@ -72,6 +73,30 @@ void shouldPass_whenFileNameMissing_inDraft() throws Exception {
         buildDraftAttachmentCreationUrl(rootId), metadata, status().isCreated());
   }
 
+  @Test
+  void shouldValidateMediaType_whenPatchingDraftAttachment() throws Exception {
+    String rootId = createDraftRootAndReturnId();
+    CdsData created =
+        requestHelper.executePostWithODataResponseAndAssertStatusCreated(
+            buildDraftAttachmentCreationUrl(rootId),
+            objectMapper.writeValueAsString(Map.of("fileName", "image.jpg")));
+    String attachmentId = (String) created.get("ID");
+
+    String attachmentUrl =
+        BASE_URL
+            + "DraftRoots_mediaValidatedAttachments(up__ID="
+            + rootId
+            + ",ID="
+            + attachmentId
+            + ",IsActiveEntity=false)";
+
+    MvcResult result =
+        requestHelper.executePatch(
+            attachmentUrl, objectMapper.writeValueAsString(Map.of("fileName", "notes.txt")));
+
+    assertThat(result.getResponse().getStatus()).isEqualTo(415);
+  }
+
   // Helper methods
   private String createDraftRootAndReturnId() throws Exception {
     CdsData response =

integration-tests/generic/src/test/java/com/sap/cds/feature/attachments/integrationtests/nondraftservice/MediaValidatedAttachmentsNonDraftTest.java

@@ -3,11 +3,14 @@
  */
 package com.sap.cds.feature.attachments.integrationtests.nondraftservice;
 
+import static org.assertj.core.api.Assertions.assertThat;
 import static org.springframework.test.web.servlet.result.MockMvcResultMatchers.status;
 
 import com.fasterxml.jackson.core.JsonProcessingException;
 import com.fasterxml.jackson.databind.ObjectMapper;
+import com.sap.cds.CdsData;
 import com.sap.cds.Result;
+import com.sap.cds.Struct;
 import com.sap.cds.feature.attachments.generated.integration.test.cds4j.sap.attachments.Attachments;
 import com.sap.cds.feature.attachments.generated.integration.test.cds4j.testservice.AttachmentEntity;
 import com.sap.cds.feature.attachments.generated.integration.test.cds4j.testservice.Roots;
@@ -26,6 +29,7 @@
 import org.junit.jupiter.params.provider.CsvSource;
 import org.springframework.http.MediaType;
 import org.springframework.test.context.ActiveProfiles;
+import org.springframework.test.web.servlet.MvcResult;
 
 @ActiveProfiles(Profiles.TEST_HANDLER_DISABLED)
 class MediaValidatedAttachmentsNonDraftTest extends OdataRequestValidationBase {
@@ -82,6 +86,29 @@ void shouldRejectAttachment_whenFileNameIsEmpty() throws Exception {
         status().isBadRequest());
   }
 
+  @Test
+  void shouldValidateMediaType_whenUpdatingNonDraftAttachment() throws Exception {
+    String rootId = createRootAndReturnId();
+    CdsData created =
+        requestHelper.executePostWithODataResponseAndAssertStatusCreated(
+            createUrl(rootId, MEDIA_VALIDATED_ATTACHMENTS),
+            objectMapper.writeValueAsString(Map.of("fileName", "image.jpg")));
+    Attachments attachment = Struct.access(created).as(Attachments.class);
+    String attachmentUrl =
+        createUrl(rootId, MEDIA_VALIDATED_ATTACHMENTS)
+            + "(ID="
+            + attachment.getId()
+            + ",up__ID="
+            + rootId
+            + ")";
+
+    MvcResult result =
+        requestHelper.executePatch(
+            attachmentUrl, objectMapper.writeValueAsString(Map.of("fileName", "notes.txt")));
+
+    assertThat(result.getResponse().getStatus()).isEqualTo(415);
+  }
+
   @Test
   void shouldAcceptUppercaseExtension_whenMimeTypeIsAllowed() throws Exception {
     String rootId = createRootAndReturnId();