Is there any way to use a @Projection interface as the default representation for a resource in SDR? Either through the SDR repositories or through a custom controller?
It used to be possible in a custom controller to do this by injecting a ProjectionFactory and using the createProjection method, but this has been broken by a recent Spring Data Rest update.
I would like to enforce a particular view on an entity, and the SDR projections seem like an ideal method for doing this, especially in the context of a HAL API, as opposed to writing hard DTO classes for a custom controller and mapping between them etc. Excerpt projections are not what I am after, as these only apply when looking at an associated resource.
To answer my own question, there's now a couple of easyish ways to do this.
You can make SDR repository finders return projections by default:
public interface PersonRepository extends PagingAndSortingRepository<Person,Long> {
Set<PersonProjection> findByLastName(String lastName);
}
You can also selectively override responses that SDR would have handled for you by default by creating a custom Spring MVC controller with the @BasePathAwareController. You will need to inject the ProjectionFactory and possibly the PagedResourcesAssembler if you're planning on providing a paged response.
@BasePathAwareController
public class CustomPersonController {
@Autowired
private ProjectionFactory factory;
@Autowired
private PersonRepository personRepository;
@Autowired
private PagedResourcesAssembler<PersonProjection> assembler;
@RequestMapping(value="/persons", method = RequestMethod.GET, produces = "application/hal+json")
public ResponseEntity<?> getPeople(Pageable pageable) {
Page<Person> people = personRepository.findAll(pageable);
Page<PersonProjection> projected = people.map(l -> factory.createProjection(PersonProjection.class, l));
PagedResources<Resource<PersonProjection>> resources = assembler.toResource(projected);
return ResponseEntity.ok(resources);
}