Pass service information within dto

Question

I need to design REST api and I faced the problem of passing additionl service information to my DTOs.

I have dto like:

public class UserDto implements Serializable {

    private Long id;
    private String login;
    private String firstName;
    private String lastName;
    private String middleName;

    // getters/setters
}

also I have endpoint with list of dtos.

I need to pass AvailableActions with every response. What is the best practice for such case? Is that correct to wrap every result with something like:

public class Wrapper<T> {

    private T data;
    private List<Action> availableActions;

    // getters/setters
}

Any ideas? Any thougths? Thanks in advance.

Answer 1

Yes, enveloping is one widely used technique, how to send metadata with the response. For example JSON API standard uses this approach.

Regarding your code itself. I prefer to generate the API from DTO objects. With JSON API and Java I use Katharsis, with which I just specify the DTO and annotate it in JPA style + create repositories for data retrieval. The wrapping with links are generated automatically (as well as all endpoints - getOne, getAll...). This way I enforce the API standard usage (JSON API) and get rid of all LinkWrappers, PaginationMetadataWrappers etc...

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Similar API construction (search_metadata attached to the response object) is used by Twitter, at least in this example.