Whitelisting Spring beans for Form flow

It is possible to use SpEL expressions in Form flows. These expressions can make use of Spring beans. This page shows how Spring beans can be used by Form flow expressions.

FormFlowBean annotation

Spring Expression Language (SpEL) by default allows access to Spring beans, e.g. to retrieve data from an external source. Valtimo uses a whitelist for this instead, as exposing every bean is a security concern. In order to add a Spring bean to this whitelist, the class itself has to be whitelisted. This is done with the @FormFlowBean annotation.

1. Ensure a bean for the class that should be whitelisted is provided.

   @Bean
   
   fun somethingService(): SomethingService{
      return SomethingService()
   }

2. At the top of the class, add the @FormFlowBean annotation.

   @FormFlowBean
   class SomethingService {
      ...
   }

The bean can now be used. For information on how to use these beans inside of a form flow definition, see here.