使用新的请求拦截器来假设客户端重试程序？

Question

I am currently building a feign client manually and passing Interceptors to it for authorization. I would like to have a smarter Retryer for some Response code.

public class myErrorEncoder extends ErrorDecoder.Default {

@Override
public Exception decode(final String methodKey, final Response response) {
    if (response.status() == 401) {
        String token = refreshToken();  // I would like to refresh the token and Edit the client
        return new RetryableException("Token Expired will retry it", null);
    } else {
        return super.decode(methodKey, response);
    }
}

}

Interceptor

@Bean public CustomInterceptor getInterceptor(String token) {
    return new CustomInterceptor(token);}

Feign builder

 private <T> T feignBuild(final Class<T> clazz, final String uri, final String token) {
    return Feign
            .builder().client(new ApacheHttpClient())
            .encoder(new GsonEncoder())
            .decoder(new ResponseEntityDecoder(feignDecoder())
            .retryer(new Retryer.Default(1,100,3))
            .errorDecoder(new ErrorDecoder())
            .requestInterceptor(getInterceptor(token))
            .contract(new ClientContract())
            .logger(new Slf4jLogger(clazz)).target(clazz, uri);
}

Now I would like to update feign client with the refreshed token and retry. Is there a way get access to the client instance and configure it.

Answer 1

Your use of the interceptor is incorrect. Interceptors are re-applied during a retry, but they are instantiated only once and are expected to be thread safe. To achieve what you are looking for will need to separate the token generation from the interceptor and have the interceptor request a new token.

public class TokenInterceptor() {
   TokenService tokenService;

   public TokenInterceptor(TokenService tokenService) {
      this.tokenService = tokenService;
   }

   public void apply(RequestTemplate template) {
      /* getToken() should create a new token */
      String token = this.tokenService.getToken();
      template.header("Authorization", "Bearer " + token);
   }
}

This will ensure that a new token is created each retry cycle.