Retrieving additional non DB information using Spring Data Rest - spring-data

Question

I am using Spring Data Rest to expose a news feed REST API. I want to add an image (location) to the entity which will be retrieved by a separate web service API call.
What is the best way to do this using Spring Data Rest or would I have to create another separate REST API call/domain object etc.?
Any sample code would be fantastic.

Answer 1

You should use a ResourceProcessor
The Spring Data REST exporter executes any discovered ResourceProcessor's before it creates the output representation
#Bean
public ResourceProcessor<Resource<MyEntity>> myEntityProcessor() {
return new ResourceProcessor<Resource<MyEntity>>() {
#Override
public Resource<MyEntity> process(Resource<MyEntity> resource) {
resource.add(new Link("http://localhost:8080/images/images.jpg", "image"));
return resource;
}
};
}
Another example with access to the repository and EntityLinks object that helps to build links related to the entity..
#Component
class MyEntityResourceProcessor implements ResourceProcessor<Resource<MyEntity>> {
#Autoware
private MyEntityRepo repo;
#Autoware
private EntityLinks entityLinks;
#Override
public Resource<MyEntity> process(Resource<MyEntity> resource) {
MyEntity entity = resource.getContent();
// Some entity processing...
Link link entityLinks.linkForSingleResource(entity).slash("...").withRel("...")
resource.add(link);
return resource;
}
}
More examples of using ResourceProcessor you can find in RESTBucks project