Pau Chorro Pau Chorro - 3 months ago 92
Java Question

Get headers feign netflix

I'm using netflix feign to communicate microservices.

So my Microservice A has an operation 'OperationA' which is consumed by the Microservice B and it passes one param by header named X-Total to B

MultiValueMap<String, String> headers = new LinkedMultiValueMap<>();
headers.add("X-Total", page.getTotalSize());


My client interface is as next:

@Headers({
"Content-Type: " + MediaType.APPLICATION_JSON_UTF8_VALUE
})
@RequestLine("GET Dto/")
List<Dto> search();

static DtoClient connect() {
return Feign.builder()
.encoder(new GsonEncoder())
.decoder(new GsonDecoder())
.target(ConditionTypeClient.class, Urls.SERVICE_URL.toString());
}


Then I've get the list of dto, but I don't know how to get the header X-TOTAL param:

public List<Dto> search() {
DtoClient client = DtoClient.connect();
return client.search();
}


How do I get the header params?

Answer

Custom decoder

You could use a custom decoder:

public class CustomDecoder extends GsonDecoder {

    private Map<String, Collection<String>> headers;

    @Override
    public Object decode(Response response, Type type) throws IOException {
        headers = response.headers();
        return super.decode(response, type);
    }

    public Map<String, Collection<String>> getHeaders() {
        return headers;
    }
}

Return Response

Other solution could be return Response instead of List<Dto>:

@Headers({
    "Content-Type: " + MediaType.APPLICATION_JSON_UTF8_VALUE
})
@RequestLine("GET Dto/")
Response search();

Then deserialize body and get headers:

Response response = Client.search();
response.headers();
Gson gson = new Gson();
gson.fromJson(response.body().asReader(), Dto.class);
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