How to consume basic-authentication protected Restful web service via REACTIVE feign client - spring-boot

Question

#ReactiveFeignClient(name = "service.b",configuration = CustomConfiguration.class)
public interface FeingConfiguration {
#PostMapping("/api/students/special")
public Flux<Student> getAllStudents(#RequestBody Flux<SubjectStudent> lista);
}
Help, how can I add a basic authentication to my header that I have in the service: service.b.
I have the CustomConfiguration.class class but it doesn't allow me, I have 401 authorization failed
#Configuration
public class CustomConfiguration {
#Bean
public BasicAuthRequestInterceptor basic() {
return new BasicAuthRequestInterceptor("user","user") ;
}

Answer 1

Looks like you are trying to use feign-reactive (https://github.com/Playtika/feign-reactive) to implement your REST clients. I am also using it for one of my projects and it looks like this library does not have an out-of-the-box way to specify basic auth credentials. At least no way to do this declaratively. So I didn't find a better way to do this than to abandon the auto-configuration via #ReactiveFeignClient and start configuring reactive feign clients manually. This way you can manually add "Authorization" header to all outgoing requests. So, provided this client definition:
public interface FeingClient {
#PostMapping("/api/students/special")
public Flux<Student> getAllStudents(#RequestBody Flux<SubjectStudent> lista);
}
Add the following configuration class to your Spring context, replacing username, password and service-url with your own data:
#Configuration
public class FeignClientConfiguration {
#Bean
FeignClient feignClient() {
WebReactiveFeign
.<FeignClient>builder()
.addRequestInterceptor(request -> {
request.headers().put(
"Authorization",
Collections.singletonList(
"Basic " + Base64.getEncoder().encodeToString(
"username:password".getBytes(StandardCharsets.ISO_8859_1))));
return request;
})
.target(FeignClient.class, "service-url");
}
}
Note, that this API for manual configurftion of reactive feign clients can differ between different versions of the reactive-feign library. Also note that this approach has a major drawback - if you start creating beans for your feign clients manually you lose the main advantage of Feign - ability to write REST-clients declaratively with just a few lines of code. E.g. if you want to use the above client with some sort of client-side load-balancing mechanism, like Ribbon/Eureka or Ribbon/Kubernetes, you will also need to configure that manually.

Answer 2

You can use a direct interceptor:
#Configuration
class FeignClientConfiguration {
#Bean
fun reactiveHttpRequestInterceptor(): ReactiveHttpRequestInterceptor {
return ReactiveHttpRequestInterceptor { request: ReactiveHttpRequest ->
request.headers()["Authorization"] = //insert data from SecurityContextHolder;
Mono.just(request)
}
}
}