Dynamic Media: Do not use Dynamic Media to generate download URLs (#123)

stefanseifert · web-flow · commit b91576cadfcd · 2025-11-24T12:20:38.000+01:00
diff --git a/changes.xml b/changes.xml
@@ -24,6 +24,14 @@
     xsi:schemaLocation="http://maven.apache.org/changes/2.0.0 https://maven.apache.org/xsd/changes-2.0.0.xsd">
   <body>
 
+    <release version="2.6.0" date="not released">
+      <action type="update" dev="sseifert" issue="123"><![CDATA[
+        Dynamic Media: Do not use Dynamic Media to generate download URLs, unless explicitly enabled via OSGi configuration (backward-compatibility mode).
+        Latest setups of Dynamic Media do not support downloading original binaries of images, thus Dynamic Media is only used for rendering image renditions and no longer for any downloads.<br/>
+        <b>Breaking change:</b> With Dynamic Media, downloads are now served via AEM DAM by default. Your can restore the previous behavior by setting <code>enableDownloads</code> to true via "wcm.io Media Handler Dynamic Media Support" OSGi configuration.
+      ]]></action>
+    </release>
+
     <release version="2.5.4" date="2025-10-16">
       <action type="fix" dev="sseifert" issue="111">
         Dynamic Media with Open API: Display thumbnail of selected remote asset on load.
diff --git a/src/main/java/io/wcm/handler/mediasource/dam/impl/DamContext.java b/src/main/java/io/wcm/handler/mediasource/dam/impl/DamContext.java
@@ -116,6 +116,8 @@ public boolean isDynamicMediaEnabled() {
     return dynamicMediaSupportService.isDynamicMediaEnabled()
         // check that DM capability is enabled for the given asset
         && dynamicMediaSupportService.isDynamicMediaCapabilityEnabled(isDynamicMediaAsset())
+        // use dynamic media only for downloads if explicitly enabled
+        && (!(mediaArgs.isDownload() || mediaArgs.isContentDispositionAttachment()) || dynamicMediaSupportService.isEnableDownloads())
         // ensure DM is not disabled within MediaArgs for this media request
         && !mediaArgs.isDynamicMediaDisabled();
   }
diff --git a/src/main/java/io/wcm/handler/mediasource/dam/impl/dynamicmedia/DynamicMediaSupportService.java b/src/main/java/io/wcm/handler/mediasource/dam/impl/dynamicmedia/DynamicMediaSupportService.java
@@ -51,6 +51,11 @@ public interface DynamicMediaSupportService {
    */
   boolean isAemFallbackDisabled();
 
+  /**
+   * @return Whether Dynamic Media should be used to deliver downloads (not recommended, backward-compatibility mode).
+   */
+  boolean isEnableDownloads();
+
   /**
    * @return Whether to validate that the renditions defined via smart cropping fulfill the requested image width/height
    *         to avoid upscaling or white borders.
diff --git a/src/main/java/io/wcm/handler/mediasource/dam/impl/dynamicmedia/DynamicMediaSupportServiceImpl.java b/src/main/java/io/wcm/handler/mediasource/dam/impl/dynamicmedia/DynamicMediaSupportServiceImpl.java
@@ -87,9 +87,18 @@ public class DynamicMediaSupportServiceImpl implements DynamicMediaSupportServic
     @AttributeDefinition(
         name = "Disable AEM Fallback",
         description = "Disable the automatic fallback to AEM-based rendering of renditions (via Media Handler) "
-            + "if Dynamic Media is enabled, but the asset has not the appropriate Dynamic Media metadata.")
+            + "if Dynamic Media is enabled, but the asset has not the appropriate Dynamic Media metadata. "
+            + "Please note that AEM is still used to deliver binaries for downloads even if this is activated, "
+            + "unless 'Enable Downloads' is activated as well (which is not recommended).")
     boolean disableAemFallback() default false;
 
+    @AttributeDefinition(
+        name = "Enable Downloads",
+        description = "Use Dynamic Media for downloads (for both image and non-image binaries). "
+            + "It is NOT recommended to enable this setting. Dynamic Media does provides reliable downloads only for non-image files, not to original binaries of images files "
+            + "(although this did work for older setups). Enable this option only if you know what you are doing (backward-compatibility mode).")
+    boolean enableDownloads() default false;
+
     @AttributeDefinition(
         name = "Validate Smart Crop Rendition Sizes",
         description = "Validates that the renditions defined via smart cropping fulfill the requested image width/height to avoid upscaling or white borders.")
@@ -134,6 +143,7 @@ public class DynamicMediaSupportServiceImpl implements DynamicMediaSupportServic
   private DynamicMediaCapabilityDetection dmCapabilityDetection;
   private boolean authorPreviewMode;
   private boolean disableAemFallback;
+  private boolean enableDownloads;
   private boolean validateSmartCropRenditionSizes;
   private Dimension imageSizeLimit;
   private boolean setImageQuality;
@@ -151,6 +161,7 @@ private void activate(Config config) {
     this.dmCapabilityDetection = config.dmCapabilityDetection();
     this.authorPreviewMode = config.authorPreviewMode();
     this.disableAemFallback = config.disableAemFallback();
+    this.enableDownloads = config.enableDownloads();
     this.validateSmartCropRenditionSizes = config.validateSmartCropRenditionSizes();
     this.imageSizeLimit = new Dimension(config.imageSizeLimitWidth(), config.imageSizeLimitHeight());
     this.setImageQuality = config.setImageQuality();
@@ -188,6 +199,11 @@ public boolean isAemFallbackDisabled() {
     return disableAemFallback;
   }
 
+  @Override
+  public boolean isEnableDownloads() {
+    return enableDownloads;
+  }
+
   @Override
   public boolean isValidateSmartCropRenditionSizes() {
     return validateSmartCropRenditionSizes;
diff --git a/src/test/java/io/wcm/handler/media/impl/MediaHandlerImplImageFileTypesEnd2EndDynamicMediaTest.java b/src/test/java/io/wcm/handler/media/impl/MediaHandlerImplImageFileTypesEnd2EndDynamicMediaTest.java
@@ -24,7 +24,6 @@
 
 import com.day.cq.dam.api.Asset;
 
-import io.wcm.handler.mediasource.dam.impl.dynamicmedia.DynamicMediaPath;
 import io.wcm.testing.mock.aem.junit5.AemContextExtension;
 import io.wcm.wcm.commons.contenttype.ContentType;
 
@@ -63,10 +62,7 @@ void testAsset_JPEG_Original_DynamicMediaDisabled() {
   @Override
   @Test
   void testAsset_JPEG_Original_ContentDisposition() {
-    Asset asset = createSampleAsset("/filetype/sample.jpg", ContentType.JPEG);
-    buildAssertMedia_ContentDisposition(asset, 100, 50,
-        "https://dummy.scene7.com/is/content/DummyFolder/sample.jpg" + DynamicMediaPath.DOWNLOAD_SUFFIX,
-        ContentType.JPEG);
+    super.testAsset_JPEG_Original_ContentDisposition();
   }
 
   @Override
@@ -242,10 +238,7 @@ void testAsset_TIFF_Original() {
   @Override
   @Test
   void testAsset_TIFF_Original_ContentDisposition() {
-    Asset asset = createSampleAsset("/filetype/sample.tif", ContentType.TIFF);
-    buildAssertMedia_ContentDisposition(asset, 100, 50,
-        "https://dummy.scene7.com/is/content/DummyFolder/sample.tif" + DynamicMediaPath.DOWNLOAD_SUFFIX,
-        ContentType.TIFF);
+    super.testAsset_TIFF_Original_ContentDisposition();
   }
 
   @Override
@@ -306,10 +299,7 @@ void testAsset_SVG_Original() {
   @Override
   @Test
   void testAsset_SVG_Original_ContentDisposition() {
-    Asset asset = createSampleAsset("/filetype/sample.svg", ContentType.SVG);
-    buildAssertMedia_ContentDisposition(asset, 100, 50,
-        "https://dummy.scene7.com/is/content/DummyFolder/sample.svg" + DynamicMediaPath.DOWNLOAD_SUFFIX,
-        ContentType.SVG);
+    super.testAsset_SVG_Original_ContentDisposition();
   }
 
   @Override
diff --git a/src/test/java/io/wcm/handler/media/impl/MediaHandlerImplImageFileTypesEnd2EndDynamicMediaWithDownloadsTest.java b/src/test/java/io/wcm/handler/media/impl/MediaHandlerImplImageFileTypesEnd2EndDynamicMediaWithDownloadsTest.java

Original file line number	Diff line number	Diff line change
`@@ -116,6 +116,8 @@ public boolean isDynamicMediaEnabled() {`
`116`	`116`	`return dynamicMediaSupportService.isDynamicMediaEnabled()`
`117`	`117`	`// check that DM capability is enabled for the given asset`
`118`	`118`	`&& dynamicMediaSupportService.isDynamicMediaCapabilityEnabled(isDynamicMediaAsset())`
	`119`	`+ // use dynamic media only for downloads if explicitly enabled`
	`120`	`+ && (!(mediaArgs.isDownload() \|\| mediaArgs.isContentDispositionAttachment()) \|\| dynamicMediaSupportService.isEnableDownloads())`
`119`	`121`	`// ensure DM is not disabled within MediaArgs for this media request`
`120`	`122`	`&& !mediaArgs.isDynamicMediaDisabled();`
`121`	`123`	`}`