Quarkus No serializer found class io.smallrye.mutiny.operators.uni.builders.UniCreateFromPublisher no properties discovered to create BeanSerializer

Question

I'm learning Quarkus Reactive with Mongo Panache and when i try to add a Metadata and Pagination object i get the error: "ERROR [io.qu.re.re.ja.ru.ma.NativeInvalidDefinitionExceptionMapper] (executor-thread-0) com.fasterxml.jackson.databind.exc.InvalidDefinitionException: No serializer found for class io.smallrye.mutiny.operators.uni.builders.UniCreateFromPublisher and no properties discovered to create BeanSerializer (to avoid exception, disable SerializationFeature.FAIL_ON_EMPTY_BEANS) (through reference chain: com.Entites.BrandResponse["data"])". Controller:

@Path("/brand/")
@Produces(MediaType.APPLICATION_JSON)
@Consumes(MediaType.APPLICATION_JSON)
@RegisterForReflection
public class brand {
  private static Logger LOG = LoggerFactory.getLogger(brand.class);

  @Inject BrandRepository br;

  @GET
  public Response list(
      @DefaultValue("0") @QueryParam("page") Integer page,
      @DefaultValue("10") @QueryParam("page_size") Integer page_size) throws JsonProcessingException {
    if (page != null && page >= 1) {
      page--;
    } else {
      page = 0;
    }
    Uni<List<ReactivePanacheMongoEntityBase>> brands = br.listBrands(page,page_size);
    return Response.ok((new BrandResponse(new Metadata("ok",200,"ok"),brands,new Pagination(3,page,page_size)))).build();
  }
}

Repository

@ApplicationScoped
@RegisterForReflection
public class BrandRepository implements ReactivePanacheMongoRepositoryBase<Brands, Integer> {

  public Uni<List<ReactivePanacheMongoEntityBase>> listBrands(Integer page, Integer page_size) {
    return Brands.findAll(Sort.by("name").ascending()).page(Page.of(page, page_size)).list();
  }
}

Entity

@Data
@RegisterForReflection
@MongoEntity(collection = "brand")
public class Brands extends ReactivePanacheMongoEntityBase {

    @BsonId
    public ObjectId id;
    @JsonProperty("name")
    @BsonProperty("name")
    public String name;
}

Entity

@RegisterForReflection
@Data
public class BrandResponse {

    @JsonProperty("metadata")
    public Metadata metadata;
    @JsonProperty("data")
    public Uni<List<ReactivePanacheMongoEntityBase>> data;
    @JsonProperty("pagination")
    public Pagination pagination;

  public BrandResponse(Metadata metadata, Uni<List<ReactivePanacheMongoEntityBase>> data, Pagination pagination) {
    this.metadata = metadata;
    this.data = data;
    this.pagination = pagination;
        }
}

Entity

@RegisterForReflection
@Data
public class Metadata {

    @JsonProperty("status")
    public String status;
    @JsonProperty("http_code")
    public Integer httpCode;
    @JsonProperty("date_time")
    public Date dateTime;
    @JsonProperty("message")
    public String message;

    public Metadata(String status, Integer httpCode, String message) {
        this.status = status;
        this.httpCode = httpCode;
        this.dateTime = new Date();
        this.message = message;
    }
}

Entity

@RegisterForReflection
@Data
public class Pagination{

    @JsonProperty("total_count")
    public Integer totalCount;
    @JsonProperty("page")
    public Integer page;
    @JsonProperty("page_size")
    public Integer pageSize;

    public Pagination(Integer totalCount, Integer page, Integer pageSize) {
        this.totalCount = totalCount;
        this.page = page;
        this.pageSize = pageSize;
    }
}

Thank You For Your Help

Answer 1

When returning some asynchronous data, you can't have any of the fields being an asynchronous type (Uni in this case). So essentially you need to convert Uni<X> to Uni<Y> and return that.

In your case you would need to make field data of BrandResponse be List<ReactivePanacheMongoEntityBase> instead of Uni<List<ReactivePanacheMongoEntityBase>>.

Once that is done you can create a BrandResponse using something like:

Uni<List<ReactivePanacheMongoEntityBase>> brands = br.listBrands(page,page_size);
Uni<BrandResponse> brandResponse = brands.onItem().transform(b -> new BrandResponse(new Metadata("ok",200,"ok"),b,new Pagination(3,page,page_size)))

Now that you have a Uni you should convert your list JAX-RS Resource Method to either return the Uni<BrandResponse> directly, or replace the return type of javax.ws.rs.core.Response to org.jboss.resteasy.reactive.RestResponse.