feign的使用，可以简化服务之间的调用，让服务之间调用更加优雅，本文从feign自定义配置和创建feign完成服务之间复杂权限验证，来进一步理解和定制feign。
本文示例参考了《Spring Cloud与Docker微服务架构实践》
自定义配置
创建Feign的配置类
@Configurationpublic class FeignConfiguration{ @Bean
public Contract feignContract(){ return new feign.Contract.Default();
} @Bean
public BasicAuthRequestInterceptor basicAuthRequestInterceptor(){ return new BasicAuthRequestInterceptor("user","password");
}
}说明：第一个@Bean配置是在FeignClient中的接口中使用Feign自带的注解； 第二个@Bean配置是在请求接口中要进行基于Http Basic的认证后才能调用。
FeignClient接口引用配置
@FeignClient(name="hello", configuration=FeignConfiguration.class)public interface HelloService{ @RequestLine("GET /message") HelloMessage hello();
}需要注意的是： FeignConfiguration类不能包含在主应用程序上下文的@ComponentScan中，否则该配置会被所有的@FeignClient共享。
Ribbon的自定义配置中也需要注意这个问题。
服务调用的复杂权限认证
上面演示了服务之间可以通过自定义配置完成基于Http Basic的认证，但是不能满足根据不同的角色不同的用户执行不同的操作，即服务之间的调用有更复杂的权限要求，就不能满足要求了，这时候要针对feign做进一步的改进。
代码示例见：hello-auth + hello-auth-consumer-feign的项目
以下是操作步骤：
引入spring-security（服务提供者）
<dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-security</artifactId> </dependency>
关键权限配置（服务提供者）
package com.example.helloauth.configuration;import org.springframework.beans.factory.annotation.Autowired;import org.springframework.context.annotation.Bean;import org.springframework.context.annotation.Configuration;import org.springframework.security.config.annotation.authentication.builders.AuthenticationManagerBuilder;import org.springframework.security.config.annotation.method.configuration.EnableGlobalMethodSecurity;import org.springframework.security.config.annotation.web.builders.HttpSecurity;import org.springframework.security.config.annotation.web.configuration.EnableWebSecurity;import org.springframework.security.config.annotation.web.configuration.WebSecurityConfigurerAdapter;import org.springframework.security.core.GrantedAuthority;import org.springframework.security.core.authority.SimpleGrantedAuthority;import org.springframework.security.core.userdetails.UserDetails;import org.springframework.security.core.userdetails.UserDetailsService;import org.springframework.security.core.userdetails.UsernameNotFoundException;import org.springframework.security.crypto.password.NoOpPasswordEncoder;import org.springframework.security.crypto.password.PasswordEncoder;import org.springframework.stereotype.Component;import java.util.ArrayList;import java.util.Collection;/**
* @author billjiang 475572229@qq.com
* @create 17-8-26
*/@Configuration@EnableWebSecurity@EnableGlobalMethodSecurity(prePostEnabled = true)public class WebSecurityConfig extends WebSecurityConfigurerAdapter { @Override
protected void configure(HttpSecurity http) throws Exception{
http.authorizeRequests().anyRequest().authenticated().and().httpBasic();
} @Bean
public PasswordEncoder passwordEncoder(){ return NoOpPasswordEncoder.getInstance();
} @Autowired
private CustomUserDetailService userDetailService; @Override
protected void configure(AuthenticationManagerBuilder auth) throws Exception{
auth.userDetailsService(this.userDetailService).passwordEncoder(this.passwordEncoder());
} @Component
class CustomUserDetailService implements UserDetailsService{ @Override
public UserDetails loadUserByUsername(String username) throws UsernameNotFoundException{ if("user".equals(username)){ return new SecurityUser("user","123456","user-role");
}else if("admin".equals(username)){ return new SecurityUser("admin","123456","admin-role");
}else{ return null;
}
}
} class SecurityUser implements UserDetails{ private static final long serialVersionUID=1L; public SecurityUser(String username,String password,String role){ super(); this.username=username; this.password=password; this.role=role;
} public SecurityUser(){
} @Override
public Collection<? extends GrantedAuthority> getAuthorities() {
Collection<GrantedAuthority> authorities=new ArrayList<>();
SimpleGrantedAuthority authority=new SimpleGrantedAuthority(this.role);
authorities.add(authority); return authorities;
} private Long id; private String username; private String password; private String role; public Long getId() { return id;
} public void setId(Long id) { this.id = id;
} @Override
public String getUsername() { return username;
} @Override
public boolean isAccountNonExpired() { return true;
} @Override
public boolean isAccountNonLocked() { return true;
} @Override
public boolean isCredentialsNonExpired() { return true;
} @Override
public boolean isEnabled() { return true;
} public void setUsername(String username) { this.username = username;
} @Override
public String getPassword() { return password;
} public void setPassword(String password) { this.password = password;
} public String getRole() { return role;
} public void setRole(String role) { this.role = role;
}
}
}启动项目hello-auth后,可以见到页面需要输入用户名和密码才能访问。
权限认证.png
服务消费者hello-auth-feign修改
1）去掉启动类上的@EnableFeignClients注解
2）去掉接口的@FeignClient的注解
package com.example.helloauthconsumerfeign.service;import com.example.helloauthconsumerfeign.model.User;import org.springframework.web.bind.annotation.GetMapping;import org.springframework.web.bind.annotation.PathVariable;/**
* @author billjiang 475572229@qq.com
* @create 17-8-23
*///@FeignClient(value="hello-auth")public interface HelloAuthService { @GetMapping("/{id}") User findById(@PathVariable("id") Long id);
}3）编写Controller类如下
package com.example.helloauthconsumerfeign.controller;import com.example.helloauthconsumerfeign.model.User;import com.example.helloauthconsumerfeign.service.HelloAuthService;import feign.Client;import feign.Contract;import feign.Feign;import feign.auth.BasicAuthRequestInterceptor;import org.springframework.beans.factory.annotation.Autowired;import feign.codec.Decoder;import feign.codec.Encoder;import org.springframework.cloud.netflix.feign.FeignClientsConfiguration;import org.springframework.context.annotation.Import;import org.springframework.web.bind.annotation.GetMapping;import org.springframework.web.bind.annotation.PathVariable;import org.springframework.web.bind.annotation.RestController;/**
* @author billjiang 475572229@qq.com
* @create 17-8-26
*/@Import(FeignClientsConfiguration.class)@RestControllerpublic class HelloAuthFeignController { private HelloAuthService userAuthService; private HelloAuthService adminAuthService; @Autowired
public HelloAuthFeignController(Decoder decoder, Encoder encoder, Client client, Contract contract){ this.userAuthService= Feign.builder().client(client).encoder(encoder).decoder(decoder).contract(contract)
.requestInterceptor(new BasicAuthRequestInterceptor("user","123456"))
.target(HelloAuthService.class,"http://hello-auth/"); this.adminAuthService= Feign.builder().client(client).encoder(encoder).decoder(decoder).contract(contract)
.requestInterceptor(new BasicAuthRequestInterceptor("admin","123456"))
.target(HelloAuthService.class,"http://hello-auth/");
} @GetMapping("/user/{id}") public User findByIdUser(@PathVariable Long id){ return this.userAuthService.findById(id);
} @GetMapping("/admin/{id}") public User findByIdAdmin(@PathVariable Long id){ return this.adminAuthService.findById(id);
}
}消费者调用
在浏览器器分别输入http://localhost:8031/admin/1和http://localhost:8031/user/2则可以完成服务之间授权的调用。
在实际业务中会根据不同的角色，执行不同的业务操作，基于以上示例可以在服务之间完成复杂的服务鉴权。
作者：billJiang
链接：https://www.jianshu.com/p/755b15ff0249
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