FeignClient with Hateoas PagedModel: Content is always empty - spring-hateoas

Question

I have an endpoint which produces Hateoas:
#GetMapping()
public ResponseEntity<PagedModel<ContentModel>> getContent(
#RequestParam(required = false) final String sortBy,
#RequestParam(defaultValue = "0") final Integer page,
#RequestParam(defaultValue = "0") final Integer size) {
// .. do stuff
}
If I use RestTemplate to call this endpoint I get the expected result.
But If I use a FeignClient:
#FeignClient(url = "${project.backend.url}/contents")
public interface ContentClient {
#GetMapping
ResponseEntity<PagedModel<ContentModel>> getContent(
#RequestParam(required = false, name = "sortBy") final String sortBy,
#RequestParam(defaultValue = "0", name = "page") final Integer page,
#RequestParam(defaultValue = "0", name = "size") final Integer size);
}
I still get a response where the metadata is correct but the content is empty:
backend-services-test_1 | 2022-03-15 11:43:29.713 INFO 80 --- [ main] d.b.b.p.p.s.c.CommonQueriesAndAsserts : body: PagedResource { content: [], metadata: Metadata { number: 0, total pages: 1, total elements: 9, size: 2147483647 }, links: }
I tried to add: #EnableHypermediaSupport(type = EnableHypermediaSupport.HypermediaType.HAL)
but that did not solve the problem.
Also this did not solve the problem: Spring Data Rest Hateoas Resources object empty when consuming with Feign client in client service
I also have this config to support jackson with HAL:
#Configuration
public class ServiceConfiguration {
#Bean
public ObjectMapper objectMapper() {
final ObjectMapper objectMapper = new ObjectMapper();
objectMapper.configure(FAIL_ON_UNKNOWN_PROPERTIES, false);
objectMapper.registerModule(new Jackson2HalModule());
return objectMapper;
}
#Bean
public MappingJackson2HttpMessageConverter converter() {
final MappingJackson2HttpMessageConverter converter = new MappingJackson2HttpMessageConverter();
converter.setSupportedMediaTypes(singletonList(HAL_JSON));
converter.setObjectMapper(objectMapper());
return converter;
}
#Bean
public TestRestTemplate testRestTemplate(final RestTemplateBuilder builder) {
return new TestRestTemplate(builder.messageConverters(converter()));
}
}
What do I need to do so that FeignClient can parse the information it gets?
EIDT
I enabled DEBUG and Feign FULL logging and I can see that the json data is correct:
backend-services-test_1 | 2022-03-15 13:24:54.947 DEBUG 81 --- [ main] d.b.b.p.p.steps.content.ContentClient : [ContentClient#getContent] <--- HTTP/1.1 200 (607ms)
backend-services-test_1 | 2022-03-15 13:24:54.947 DEBUG 81 --- [ main] d.b.b.p.p.steps.content.ContentClient : [ContentClient#getContent] cache-control: no-cache, no-store, max-age=0, must-revalidate
backend-services-test_1 | 2022-03-15 13:24:54.947 DEBUG 81 --- [ main] d.b.b.p.p.steps.content.ContentClient : [ContentClient#getContent] connection: keep-alive
backend-services-test_1 | 2022-03-15 13:24:54.947 DEBUG 81 --- [ main] d.b.b.p.p.steps.content.ContentClient : [ContentClient#getContent] content-type: application/json
backend-services-test_1 | 2022-03-15 13:24:54.947 DEBUG 81 --- [ main] d.b.b.p.p.steps.content.ContentClient : [ContentClient#getContent] date: Tue, 15 Mar 2022 12:24:54 GMT
backend-services-test_1 | 2022-03-15 13:24:54.947 DEBUG 81 --- [ main] d.b.b.p.p.steps.content.ContentClient : [ContentClient#getContent] expires: 0
backend-services-test_1 | 2022-03-15 13:24:54.948 DEBUG 81 --- [ main] d.b.b.p.p.steps.content.ContentClient : [ContentClient#getContent] keep-alive: timeout=60
backend-services-test_1 | 2022-03-15 13:24:54.948 DEBUG 81 --- [ main] d.b.b.p.p.steps.content.ContentClient : [ContentClient#getContent] pragma: no-cache
backend-services-test_1 | 2022-03-15 13:24:54.948 DEBUG 81 --- [ main] d.b.b.p.p.steps.content.ContentClient : [ContentClient#getContent] transfer-encoding: chunked
backend-services-test_1 | 2022-03-15 13:24:54.948 DEBUG 81 --- [ main] d.b.b.p.p.steps.content.ContentClient : [ContentClient#getContent] x-content-type-options: nosniff
backend-services-test_1 | 2022-03-15 13:24:54.948 DEBUG 81 --- [ main] d.b.b.p.p.steps.content.ContentClient : [ContentClient#getContent] x-frame-options: DENY
backend-services-test_1 | 2022-03-15 13:24:54.948 DEBUG 81 --- [ main] d.b.b.p.p.steps.content.ContentClient : [ContentClient#getContent] x-xss-protection: 1; mode=block
backend-services-test_1 | 2022-03-15 13:24:54.948 DEBUG 81 --- [ main] d.b.b.p.p.steps.content.ContentClient : [ContentClient#getContent]
backend-services-test_1 | 2022-03-15 13:24:54.967 DEBUG 81 --- [ main] d.b.b.p.p.steps.content.ContentClient : [ContentClient#getContent] {
backend-services-test_1 | "links" : [ {
backend-services-test_1 | "rel" : "self",
backend-services-test_1 | "href" : "http://backend-services:8082/contents?sortBy&page=0&size=2000"
backend-services-test_1 | } ],
backend-services-test_1 | "content" : [ {
backend-services-test_1 | "key" : {
backend-services-test_1 | "id" : 1,
backend-services-test_1 | "version" : "2.0"
backend-services-test_1 | },
backend-services-test_1 | "type" : "CONTENT",
backend-services-test_1 | "title" : "Title",
backend-services-test_1 | "subtitle" : "Subtitle",
backend-services-test_1 | }, {
backend-services-test_1 | "key" : {
backend-services-test_1 | "id" : 2,
backend-services-test_1 | "version" : "2.0"
backend-services-test_1 | },
backend-services-test_1 | "type" : "CONTENT",
backend-services-test_1 | "title" : "Title",
backend-services-test_1 | "subtitle" : "Subtitle",
...
backend-services-test_1 | } ],
backend-services-test_1 | "page" : {
backend-services-test_1 | "size" : 2147483647,
backend-services-test_1 | "totalElements" : 9,
backend-services-test_1 | "totalPages" : 1,
backend-services-test_1 | "number" : 0
backend-services-test_1 | }
backend-services-test_1 | }
EIDT 2
Adding:
<dependency>
<groupId>io.github.openfeign</groupId>
<artifactId>feign-jackson</artifactId>
<version>9.3.1</version>
</dependency>
and:
#Bean
public Decoder feignDecoder() {
return new ResponseEntityDecoder(new JacksonDecoder(objectMapper()));
}
Also did not solve the problem.

Answer 1

So with the custom feign decoder I was on the right path.
Here the full config which made it working:
#Configuration
public class FeignConfiguration {
#Bean
Logger.Level feignLoggerLevel() {
return Level.FULL;
}
#Bean
public ObjectMapper objectMapper() {
return new ObjectMapper()
.configure(FAIL_ON_UNKNOWN_PROPERTIES, false)
.registerModule(new Jackson2HalModule());
}
#Bean
public MappingJackson2HttpMessageConverter converter() {
final MappingJackson2HttpMessageConverter converter = new MappingJackson2HttpMessageConverter();
converter.setSupportedMediaTypes(singletonList(HAL_JSON));
converter.setObjectMapper(objectMapper());
return converter;
}
#Bean
public Decoder feignDecoder() {
return new ResponseEntityDecoder(
new SpringDecoder(
() -> new HttpMessageConverters(converter())));
}
}