Using #Headers with dynamic values in Feign client + Spring Cloud (Brixton RC2) - spring

Question

Is it possible to set dynamic values to a header ?
#FeignClient(name="Simple-Gateway")
interface GatewayClient {
#Headers("X-Auth-Token: {token}")
#RequestMapping(method = RequestMethod.GET, value = "/gateway/test")
String getSessionId(#Param("token") String token);
}
Registering an implementation of RequestInterceptor adds the header but there is no way of setting the header value dynamically
#Bean
public RequestInterceptor requestInterceptor() {
return new RequestInterceptor() {
#Override
public void apply(RequestTemplate template) {
template.header("X-Auth-Token", "some_token");
}
};
}
I found the following issue on github and one of the commenters (lpborges) was trying to do something similar using headers in #RequestMapping annotation.
https://github.com/spring-cloud/spring-cloud-netflix/issues/288
Kind Regards

Answer 1

The solution is to use #RequestHeader annotation instead of feign specific annotations
#FeignClient(name="Simple-Gateway")
interface GatewayClient {
#RequestMapping(method = RequestMethod.GET, value = "/gateway/test")
String getSessionId(#RequestHeader("X-Auth-Token") String token);
}

Answer 2

The #RequestHeader did not work for me. What did work was:
#Headers("X-Auth-Token: {access_token}")
#RequestLine("GET /orders/{id}")
Order get(#Param("id") String id, #Param("access_token") String accessToken);

Answer 3

#HeaderMap,#Header and #Param didn't worked for me, below is the solution to use #RequestHeader when there are multiple header parameters to pass using FeignClient
#PostMapping("/api/channelUpdate")
EmployeeDTO updateRecord(
#RequestHeader Map<String, String> headerMap,
#RequestBody RequestDTO request);
code to call the proxy is as below:
Map<String, String> headers = new HashMap<>();
headers.put("channelID", "NET");
headers.put("msgUID", "1234567889");
ResponseDTO response = proxy.updateRecord(headers,requestDTO.getTxnRequest());

Answer 4

I have this example, and I use #HeaderParam instead #RequestHeader :
import rx.Single;
import javax.ws.rs.Consumes;
import javax.ws.rs.HeaderParam;
import javax.ws.rs.POST;
import javax.ws.rs.Path;
import javax.ws.rs.core.HttpHeaders;
import javax.ws.rs.core.MediaType;
#Consumes(MediaType.APPLICATION_JSON)
public interface FeignRepository {
#POST
#Path("/Vehicles")
Single<CarAddResponse> add(#HeaderParam(HttpHeaders.AUTHORIZATION) String authorizationHeader, VehicleDto vehicleDto);
}

Answer 5

You can use HttpHeaders.
#PostMapping(path = "${path}", consumes = MediaType.APPLICATION_JSON_VALUE, produces = MediaType.APPLICATION_JSON_VALUE)
ResponseEntity<?> callService(#RequestHeader HttpHeaders headers, #RequestBody Object object);
private HttpHeaders getHeaders() {
HttpHeaders headers = new HttpHeaders();
headers.add("Authorization", "1234");
headers.add("CLIENT_IT", "dummy");
return headers;
}

Answer 6

I use #HeaderMap as it seems very handy if you are working with Open feign. Using this way you can pass header keys and values dynamically.
#Headers({"Content-Type: application/json"})
public interface NotificationClient {
#RequestLine("POST")
String notify(URI uri, #HeaderMap Map<String, Object> headers, NotificationBody body);
}
Now create feign REST client to call the service end point, create your header properties map and pass it in method parameter.
NotificationClient notificationClient = Feign.builder()
.encoder(new JacksonEncoder())
.decoder(customDecoder())
.target(Target.EmptyTarget.create(NotificationClient.class));
Map<String, Object> headers = new HashMap<>();
headers.put("x-api-key", "x-api-value");
ResponseEntity<String> response = notificationClient.notify(new URI("https://stackoverflow.com/example"), headers, new NotificationBody());

Answer 7

A bit late to the game here, but if one needs an enforced, templated value, I discovered that this works in Spring Boot. Apparently, as long as the toString() gives a valid header value, you can use any type.
#FeignClient(
name = "my-feign-client",
url = "http://my-url.com"
)
public interface MyClient {
#GetMapping(
path = "/the/endpoint",
produces = MediaType.APPLICATION_JSON_VALUE
)
DataResponse getData(#RequestHeader(HttpHeaders.AUTHORIZATION) BearerHeader bearerHeader);
final class BearerHeader {
private final String token;
private BearerHeader(String token) {
this.token = token;
}
#Override
public String toString() {
return String.format("Bearer %s", token);
}
public static BearerHeader of(String token) {
return new BearerHeader(token);
}
}