OpenFeign客户端问题：多个Basic Authentication令牌被应用到同一请求

问题原因 #

Spring Cloud Feign会自动收集Spring容器中所有类型为RequestInterceptor的Bean，并将其应用到所有Feign客户端实例中。你定义的两个BasicAuthRequestInterceptor（分别对应app1和app2）都被注册为全局Bean，导致每个Feign客户端的请求都会带上两个Auth头，触发服务端400错误。

解决方案 #

方法一：通过作用域隔离配置类

给每个Feign配置类添加@Configuration和@Scope("feignClient")注解，确保每个Feign客户端拥有独立的配置实例，拦截器不会跨客户端共享：

AppOneFeignClientConfiguration 修改后

import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.Scope;
import feign.Logger;
import feign.auth.BasicAuthRequestInterceptor;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.context.annotation.Bean;

@Configuration
@Scope("feignClient")
public class AppOneFeignClientConfiguration {
    @Bean
    public BasicAuthRequestInterceptor appOneBasicAuthRequestInterceptor(
            @Value("${app1_user_name}") String username,
            @Value("${app1_password}") String password
    ) {
        return new BasicAuthRequestInterceptor(username, password);
    }

    @Bean
    Logger.Level appOneFeignLoggerLevel() {
        return Logger.Level.BASIC;
    }
}

AppTwoFeignClientConfiguration 修改后

import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.Scope;
import feign.Logger;
import feign.auth.BasicAuthRequestInterceptor;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.context.annotation.Bean;

@Configuration
@Scope("feignClient")
public class AppTwoFeignClientConfiguration {
    @Bean
    public BasicAuthRequestInterceptor appTwoBasicAuthRequestInterceptor(
            @Value("${app2_user_name}") String username,
            @Value("${app2_password}") String password
    ) {
        return new BasicAuthRequestInterceptor(username, password);
    }

    @Bean
    Logger.Level appTwoFeignLoggerLevel() {
        return Logger.Level.BASIC;
    }
}

方法二：通过Feign.Builder直接配置拦截器

不将BasicAuthRequestInterceptor注册为全局Bean，而是在配置类中构建专属的Feign.Builder，拦截器仅作用于当前客户端：

AppOneFeignClientConfiguration 修改后

import feign.Feign;
import feign.Logger;
import feign.auth.BasicAuthRequestInterceptor;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.context.annotation.Bean;

public class AppOneFeignClientConfiguration {
    @Bean
    public Feign.Builder feignBuilder(@Value("${app1_user_name}") String username,
                                      @Value("${app1_password}") String password) {
        return Feign.builder()
                .requestInterceptor(new BasicAuthRequestInterceptor(username, password))
                .logLevel(Logger.Level.BASIC);
    }
}

AppTwoFeignClientConfiguration 修改后

import feign.Feign;
import feign.Logger;
import feign.auth.BasicAuthRequestInterceptor;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.context.annotation.Bean;

public class AppTwoFeignClientConfiguration {
    @Bean
    public Feign.Builder feignBuilder(@Value("${app2_user_name}") String username,
                                      @Value("${app2_password}") String password) {
        return Feign.builder()
                .requestInterceptor(new BasicAuthRequestInterceptor(username, password))
                .logLevel(Logger.Level.BASIC);
    }
}

验证 #

修改完成后，调用AppOneClient.getName()时只会携带app1的Basic Auth头，调用AppTwoClient.getAddress()时只会携带app2的Auth头，不会再出现头重复的问题。

内容的提问来源于stack exchange，提问作者RohitG