CODEWITHSUNDEEP
spring-bootheaderresponsefeign
somya jain
somya jain

Reputation: 69

How to read header value from feign Response

i am using spring boot to call a openfeign client and from the Response of that feign i need to extract some header values.how can i do that. can anybody help please. just help me wheather we can do that or not!

Upvotes: 6

Views: 9425

Answers (3)

dbaltor
dbaltor

Reputation: 3373

Yes, you can do that. With Feign, we usually declare our interface with the method returning our class and Feign will automatically de-serialise the response from JSON into our POJO.

Here is the interface (operation):

@FeignClient(name = "library-book-service")
@RequestMapping("books")
public interface BookClient {

    @GetMapping
    public List<Book> getBooks(
        @RequestParam("page") Integer pageNum,
        @RequestParam("size") Integer pageSize,
        @RequestParam("reader") Long readerId);
}

And then you can use the feign client like this:

@Service
@RequiredArgsConstructor
public class BookService {
    private final @NonNull BookClient bookClient;

    public List<Book> retrieveBooks(
        Integer pageNum, 
        Integer pageSize, 
        Long readerId) {

            return bookClient.getBooks(pageNum, pageSize, readerId);
    }

However, in order to have access to the response headers, you need to declare your methods to return feign.Response.

import feign.Response;

@FeignClient(name = "library-book-service")
@RequestMapping("books")
public interface BookClient {

    @GetMapping
    public Response getBooks(
        @RequestParam("page") Integer pageNum,
        @RequestParam("size") Integer pageSize,
        @RequestParam("reader") Long readerId);
}

This way you can have access to the response body and headers:

@Service
@RequiredArgsConstructor
public class BookService {
    private final @NonNull BookClient bookClient;
    private final @NonNull ObjectMapper objectMapper;

    public List<Book> retrieveBooks(
        Integer pageNum, 
        Integer pageSize, 
        Long readerId) {

          var response = bookClient.getBooks(pageNum, pageSize, readerId);
          if (response == null) {
            return Collections.emptyList();
          }

          // retrieve body
          var books = objectMapper.readValue(
            new BufferedReader(new InputStreamReader(response.body().asInputStream(), StandardCharsets.UTF_8)),
            new TypeReference<List<Book>>(){});

          // retrieve headers
          Map<String, Collection<String>> headers = response.headers();
          // ... do whatever you need with the headers

          return books;
    }

Upvotes: 7

jaco0646
jaco0646

Reputation: 17066

Presumably you want to retrieve both the (deserialized) response body as well as the response headers. In that case, returning a ResponseEntity is ideal because it includes both.

import org.springframework.cloud.openfeign.FeignClient;
import org.springframework.http.ResponseEntity;
import org.springframework.web.bind.annotation.GetMapping;
import static org.springframework.http.MediaType.APPLICATION_JSON_VALUE;

@FeignClient(name = "HttpStatusClient", url = "https://httpstat.us")
interface HttpStatusClient {
    record HttpStatus(int code, String description){}

    @GetMapping(path = "/200", produces = APPLICATION_JSON_VALUE)
    ResponseEntity<HttpStatus> twoHundred();
}

Upvotes: 1

tayfurunal
tayfurunal

Reputation: 79

You can use import feign.Response as a response like:

@PostMapping("/test")
Response test(@RequestBody TestRequest testRequest);

then you can reach http header

response.headers().get(HEADER_NAME).toString();

if you want get body in this case you have to some json-string manipulation by use response.body() this page may help you for this

Upvotes: 2

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