AEM – Custom namespace

Purpose of a namespace

Namespace primarily helps you organize and manage your metadata. For example, it could help you:

• Identify custom metadata against OOTB metadata
• Identify a metadata’s source: when metadata flows-in from from multiple 3rd party systems
  • In such scenario, you could easily identify the source of metadata, by mapping a namespace against the metadata’s scource.
• Filter what should be written on to an asset binary by Metadata Writeback Workflow. The DAM metadata writeback workflow would only write a metadata that has a namespace.

Registering a new name space

A namespace can be registered in AEM through multiple ways as listed below:

Via CRX Explorer:

• Visit CRX Explorer http://localhost:4502/crx/explorer/index.jsp

• Click on “Node Type Administration“, followed by “>>” on the toolbar, then “Namespaces“

• Scroll to the bottom of the page. Click on “New” button.

• Specify the id in the form of a URI

• Add a prefix for the id. Id is the namespace that you would append to a property name. Example: techrevel:title

• Save the config. Click on apply.

The new namespace (example: techrevel) should now be available for use.

Note: The CRX explorer way needs you to register the namespace on every system manually (Local developer’s instances and servers).

Via CND File

The CND File way has a advantage, that the namespace will be automatically registered on deploying code.

• Create a nodetypes.cnd at the location /src/main/content/META-INF/vault/nodetypes.cnd of ui.content module
• Register you namespace as shown in the example below

<'sling'='http://sling.apache.org/jcr/sling/1.0'>
<'nt'='http://www.jcp.org/jcr/nt/1.0'>
<'techrevel'='http://www.techrevel.blog'>

[sling:Folder] > nt:folder
  - * (undefined)
  - * (undefined) multiple
  + * (nt:base) = sling:Folder version

Once you deploy the code, the namespace would be available for use

Deleting a namespace

• Visit CRX Explorer http://localhost:4502/crx/explorer/index.jsp
• Click on “Content Explorer”

• Browse to location “/jcr:system/rep:namespaces”

• Look for the namespace in the list displayed on clicking rep:namespaces node
• Right click the namespace. Click delete.

• Remember to save the changes via “Save All” button

The namespace would have been deregistered now. AEM restart is not required.