Version 5 supported

Unique keys

There are several cases where you may want to generate a unique key. For example:

  • populate ID attribute in your HTML output
  • key for partial cache

If this is for a public-facing purpose, it is typically considered bad practice to expose the database ID, as this provides unnecessary information to would-be attackers. Instead, for DataObject subclasses, you can use the getUniqueKey() method.

This can be done simply by including following code in your template:



The unique key generation can be altered in two ways:

  1. you can provide extra data to be used when generating a key via an extension
  2. you can inject over the key generation service and write your own custom code.

Extension point

The cacheKeyComponent extension hook is invoked from DataObject::getUniqueKeyComponents(). Simply implement a cacheKeyComponent() method in an Extension applied to the DataObject class you want to affect. The method must return a string, which will be used when generating a unique key for the record.

Some cases where this is used in supported modules already are:

  • versions - an object in different version stages needs to have different unique keys for each stage
  • locales - an object in different locales needs to have different unique keys for each locale

See Extensions and DataExtensions for more information about implementing and applying extensions.

Custom service

UniqueKeyService is used by default but you can use injector to override it with your custom service. For example:

    class: App\Service\MyCustomService

Your custom service has to implement UniqueKeyInterface.

A use case for implementing your own service might be to produce a UUID for each record.