In Adobe Experience Manager (AEM) Assets, a metadata schema defines the layout of the properties page and the metadata properties displayed for assets that use the particular schema. Metadata properties include title, description, MIME types, tags, and so on.
You can use the Metadata Schema Forms editor to modify existing schemas or add custom metadata schemas.
- To view the properties page for an asset, click or tap the View Properties icon from Quick Actions on the asset tile in Card view. Alternatively, select the asset in the UI and then click or tap the Properties icon from the toolbar.
- Edit various metadata properties under the various tabs. However, you cannot modify the asset type in the properties page. To modify the MIME type for an asset, use a custom metadata schema form or modify an existing form. See Editing Metadata Schema Forms for more information. If you modify the metadata schema for a certain MIME type, the properties page layout for assets with the current MIME type and all asset subtypes are modified. For example, modifying a jpeg schema under default/image only modifies the metadata layout (asset properties) for assets with MIME type image/jpeg . However, if you edit the default schema, your changes modify the metadata layout for all types of assets.
- To view a list of forms/templates, click the AEM logo and then navigate to Tools > Assets > Metadata Schemas . AEM provides the following templates out of the box:
The following child forms inherit the properties of the default form: i. image : Schema form for assets with the MIME type "image", for example, image/jpeg , image/png , and so on. The "image" form has the following child form templates: a. jpeg : Schema form for assets with sub type jpeg . b. tiff : Schema form for the assets with sub type tiff .ii. application : Schema form for assets with MIME type application , for example application/pdf , application/zip , and so on. a. pdf : Schema form for assets with sub type pdf .iii. video : Schema form for assets with MIME type video , such as video/avi , video/mp4 , and so on.
- default : The base metadata schema form for assets.
- collection : Schema form for collections.
- contentfragment: Schema form for Content Fragments.
To view the child forms of a schema form, click/tap the schema form name.
Add a metadata schema form
- To add a custom template to the list, click Create from the toolbar.Unedited templates have a lock icon before them. If you customize any of the templates, the lock icon before the template disappears.
- In the dialog, enter the title of the Schema form, and then click Create to complete the form creation process.
Edit metadata schema forms
You can edit a newly-added or existing metadata schema form. The metadata schema form includes the following:
- Form items within tabs.
You can map/configure these form items to a field within a metadata node in the CRX repository.
You can add new tabs or form items to the metadata schema form. The tabs and form items derived from the parent are in the locked state. You cannot alter them at the child level.
- In the Schema Forms page, select the check box before a form and then click the Edit icon on the toolbar.
- In the Metadata Schema Editor page, customize the properties page of the asset by dragging one or more components from the list of component types in the Build Form tab to the Basic tab.
- To configure a component, select it and modify its properties in the Settings tab.
Components within the Build Form tab
The Build Form tab lists form items that you use in your schema form. The Settings tab provides the attributes of each item that you select in the Build Form tab. The following table lists the form items available in the Build Form tab:
|Section Header||Add a section heading for a list of common components.|
|Single Line Text||Add a single line text property. It is stored as a string.|
|Multi Value Text||Add a multi value text property. It is stored as a string array.|
|Number||Add a number component.|
|Date||Add a date component.|
|Dropdown||Add a dropdown list.|
|Standard Tags||Add a tag.|
|Smart Tags||Add to augment search capabilities by automatically adding metadata tags.|
|Hidden Field||Add a hidden field. It is sent as a POST parameter when the asset is saved.|
|Asset Referenced By||Add this component to view list of assets referenced by the asset.|
|Asset Referencing||Add to display a list of assets that reference the asset.|
|Products References||Add to show the list of products linked with the asset.|
|Asset Rating||Add to display options for rating the asset.|
|Contextual Metadata||Add to control the display of other metadata tabs in the properties page of assets.|
Edit the metadata component
To edit the properties of a metadata component on the form, click the component and edit all or a subset of the following properties in the Settings tab.
Field Label : The name of the metadata property that is displayed on the properties page for the asset.
Map to Property : This property specifies the relative path/name to the asset node where it is saved in the CRX repository. It starts with ./ because indicating that the path is under the asset's node.
The following are the valid values for this property:
- . /jcr:content/metadata/dc:title : Stores the value at the asset's metadata node as the property dc:title .
- . /jcr:created : Displays the jcr property at the asset's node. If you configure these properties on view properties, we recommend that you mark them as Disable Edit, because they are protected. Otherwise, the error "Asset(s) failed to modify" occurs when you save the asset's properties.
To ensure that the component is displayed properly in the metadata schema form, the property path should not include any spaces.
Placeholder : Use this property to specify relevant placeholder text regarding the metadata property.
Required : Use this property to mark a metadata property as mandatory on the properties page.
Disable Edit : Use this property to make a metadata property not editable on the Properties page.
Show Empty Field In Read Only : Mark this property to display a metadata property on the properties page even if it has no value. By default, when a metadata property has no value, it is not be listed on the properties page.
Show list ordered : Use this property to display an ordered list of choices
Choices : Use this property to specify choices in a list
Description : Use this property to add a short description for the metadata component.
Class : Object class the property is associated with.
Delete : Click to delete a component from the schema form.
The Hidden Field component does not include these attributes. Instead, it includes properties, such as attributes Name, Value, Field Label, and Description. The values for the Hidden Field component are sent as a POST parameter whenever the asset is saved. It is not be saved as metadata for the asset.
If you select the Required option, you can search for assets missing mandatory metadata. From the Filters panel, expand the Metadata Validation predicate and select the Invalid option. The search results display assets missing mandatory metadata that you configured through the schema form.
If you add the Contextual Metadata component to any tab of any schema form, the component appears as a list in the properties page of assets to which the particular schema is applied. The list includes all other tabs except the tab to which you applied the Contextual Metadata component. Currently, this feature provides basic functionality to control the display of metadata based on the context.
To include any tab in the properties page in addition to the tab where the Contextual Metadata component is applied, select the tab from the list. The tab is added to the properties page.
Specify properties in JSON file
Instead of specifying properties for the options in the Settings tab, you can define the options in a JSON file by specifying corresponding key-value pairs. Specify the path of the JSON file in the JSON Path field.
Add and delete a tab in the schema form
The schema editor lets you add or delete a tab. The default schema form includes the Basic , Advanced , IPTC , and IPTC Extension tabs, by default.
Click + to add a new tab on a schema form. By default, the new tab has the name Unnamed-1 . You can modify the name from the Settings tab. Click X to delete a tab.
Deleting metadata schema forms
AEM lets you delete custom schema forms only. It does not let you delete the default schema forms/templates. However, you can delete any custom changes in these forms.
To delete a form, select a form and click the delete icon.
After you delete custom changes to a default form, the lock icon reappears before it on the Metadata Schema interface to indicate that the form reverted to its default state.
You cannot delete the out of the box metadata schema forms in AEM Assets.
Schema forms for MIME types
AEM Assets provides default forms for various MIME types out of the box. However, you can add custom forms for assets of various MIME types.
Adding new forms for MIME types
Create a new form under the appropriate form type. For example, to add a new template for the image/png subtype, create the form under the "image" forms. The title for the schema form is the subtype name. In this case, the title is "png. "
Using an existing schema template for various MIME types
You can use an existing template for a different MIME type. For example, use the image/jpeg form for assets of MIME type image/png .
In this case, create a new node at /etc/dam/metadataeditor/mimetypemappings in the CRX repository. Specify a name for the node and define the following properties:
Name of the existing form to be mapped
List of MIME types that use the form defined in the exposedmimetype attribute
AEM Assets maps the following MIME types and schema forms:
video/avi, video/msvideo, video/x-msvideo
Granting access to metadata schemas
The Metadata Schema feature is available to administrators only. However, administrators can provide access to non administrators by modifying some permissions. The non administrator should have create, modify, and delete permissions on the /conf folder.
Applying folder-specific metadata
AEM Assets lets you define a variant of a metadata schema and apply it to a specific folder.
For example, you can define a variant of the default metadata schema and apply it to a folder. When you apply the modified schema, it overrides the original default metadata schema that is applied to assets within the folder.
Only assets uploaded to the folder to which this schema is applied will conform to the modified metadata defined in the variant metadata schema.
Assets in other folders where the original schema is applied continue to conform to metadata defined in the original schema.
Metadata inheritance by assets is based on the schema that is applied to the first-level folder in the hierarchy. In other words, if a folder does not contain subfolders, the assets within the folder inherit the metadata from the schema applied to the folder.
If the folder has a subfolder, the assets within the subfolder inherit the metadata from the schema applied at the subfolder level if a different schema is applied at the subfolder level. If, however, no schema or the same schema is applied at the subfolder level, the subfolder assets inherit the metadata from the schema applied at the parent folder level.
- Click the AEM logo and then navigate to Tools > Assets > Metadata Schemas . The Metadata Schema Forms page is displayed.
- Select the check box before a form, for example the default metadata form, and click or tap the copy icon and save it as a custom form. Specify a custom name for the form, for example my_default . Alternatively, you can create a custom form.
- In the Metadata Schema Forms page, select the my_default form, and then click the Edit icon.
- In the Metadata Schema Editor page, add a text field to the schema form. For example add a field with the label Category .
- Click Save . The modified form is listed in the Metadata Schema Forms page.
- Click/tap Apply to Folder(s) from the toolbar to apply the custom metadata to a folder.
- Select the folder on which to apply the modified schema and then click/tap Apply .
- If the folder has the other metadata schema applied, a message appears warning that you are about to overwrite the existing metadata schema. Click Overwrite .
- Click OK to close the success message.
- Navigate to the folder to which you applied the modified metadata schema.
Defining mandatory metadata
You can define mandatory fields at a folder level, which is enforced on assets that are uploaded to the folder. If you upload assets with missing metadata for the mandatory fields defined earlier, a visual indication for missing metadata appears on the assets in the Card view.
A metadata field can be defined as mandatory based on the value of another field. In the Cards view, AEM does not display the warning message about missing metadata for such mandatory metadata fields.
- Click the AEM logo and then navigate to Tools > Assets > Metadata Schemas . The Metadata Schema Forms page is displayed.
- Save the default metadata form as a custom form. For example, save it as my_default .
- Edit the custom form. Add a mandatory field. For example, add a Category field and make the field mandatory.
- Click Save . The modified form is listed in the Metadata Schema Forms page. Select the form and then click or tap Apply to Folder(s) from the toolbar to apply the custom metadata to a folder.
- Navigate to the folder and upload some assets with missing metadata for the mandatory field you added to the custom form. A message for the missing metadata for the mandatory field is displayed on the Card view of the asset.
- (Optional) Access https://[server]:[port]/system/console/components/ . Configure and enable com.day.cq.dam.core.impl.MissingMetadataNotificationJob component that is disabled by default. Set a frequency at which AEM checks for the validity of metadata on the assets.This configuration adds a property hasValidMetadata to jcr:content of assets. Using this property, AEM can filter results in a search.If an asset is added after the scheduled check, the asset is not flagged with hasValidMetadata until the next scheduled check. The assets does not appear in intermediate search results.The metadata validation checks are resource intensive and may impact the performance of your system. Schedule the checks accordingly. If the server cannot cope up with the load, try disabling this job