Spring Security对接OIDC(OAuth2)外部认证

前后端分离项目对接OIDC(OAuth2)外部认证，认证服务器可以使用Keycloak。

后端已有用户管理和权限管理，需要外部认证服务器的用户名和业务系统的用户名一致才可以登录。

后台基于Spring Boot 2.7 + Spring Security

流程：

1. 前台浏览器跳转到  后台地址 + /login/oauth2/authorization/my-oidc-client
2. 后台返回302重定向，重定向到登录外部认证服务器 http://my-oidc-provider.com
3. 在外部认证网页登录成功后，自动重定向到前台地址 http://localhost/login ,前台取得URL中的参数，使用这些参数发送ajax post请求到  后台地址 + /login/oauth2/my-oidc-client
4. 后台会自动与 http://my-oidc-provider.com 交互完成登录，并使用用户名取得本地用户信息后返回json
5. 如果第4步失败，则返回自定义的错误信息json
    

(1)引入依赖：

org.springframework.boot:spring-boot-starter-oauth2-client

(2)配置文件：

 
spring.security.oauth2.client.registration.my-oidc-client.provider=my-oidc-provider
spring.security.oauth2.client.registration.my-oidc-client.client-id=my-client-id
spring.security.oauth2.client.registration.my-oidc-client.client-secret=my-client-secret
spring.security.oauth2.client.registration.my-oidc-client.authorization-grant-type=authorization_code
spring.security.oauth2.client.registration.my-oidc-client.scope=openid,profile
spring.security.oauth2.client.registration.my-oidc-client.redirect-uri=http://localhost/login
spring.security.oauth2.client.provider.my-oidc-provider.issuer-uri=http://my-oidc-provider.com

(3)Spring Security配置类：

package com.example.demo.config;
 
import java.io.IOException;
 
import javax.servlet.ServletException;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
 
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.core.convert.converter.Converter;
import org.springframework.security.config.annotation.ObjectPostProcessor;
import org.springframework.security.config.annotation.web.builders.HttpSecurity;
import org.springframework.security.config.annotation.web.configuration.EnableWebSecurity;
import org.springframework.security.core.Authentication;
import org.springframework.security.core.AuthenticationException;
import org.springframework.security.core.userdetails.UserDetails;
import org.springframework.security.core.userdetails.UserDetailsService;
import org.springframework.security.oauth2.client.authentication.OAuth2AuthenticationToken;
import org.springframework.security.oauth2.client.authentication.OAuth2LoginAuthenticationToken;
import org.springframework.security.oauth2.client.oidc.web.logout.OidcClientInitiatedLogoutSuccessHandler;
import org.springframework.security.oauth2.client.registration.ClientRegistrationRepository;
import org.springframework.security.oauth2.client.web.OAuth2LoginAuthenticationFilter;
import org.springframework.security.oauth2.core.oidc.user.OidcUser;
import org.springframework.security.web.SecurityFilterChain;
import org.springframework.security.web.authentication.SimpleUrlAuthenticationFailureHandler;
import org.springframework.security.web.authentication.SimpleUrlAuthenticationSuccessHandler;
import org.springframework.security.web.authentication.logout.LogoutSuccessHandler;
 
import com.fasterxml.jackson.core.JsonProcessingException;
import com.fasterxml.jackson.databind.ObjectMapper;
 
@Configuration
@EnableWebSecurity
public class MyOAuth2SecurityConfig {
    
    private final UserDetailsService userDetailsService;
    private final ClientRegistrationRepository clientRegistrationRepository;
    private final ObjectMapper objectMapper;
 
    public MyOAuth2SecurityConfig(UserDetailsService userDetailsService, ClientRegistrationRepository clientRegistrationRepository, ObjectMapper objectMapper) {
        this.userDetailsService = userDetailsService;
        this.clientRegistrationRepository = clientRegistrationRepository;
        this.objectMapper = objectMapper;
    }
 
    @Bean
    public SecurityFilterChain oauth2SecurityFilterChain(HttpSecurity http) throws Exception {
        http
        .authorizeHttpRequests(httpRequests -> httpRequests.anyRequest().authenticated())
        .oauth2Login(oauth2Login -> oauth2Login
            .authorizationEndpoint(authorization -> authorization
                .baseUri("/login/oauth2/authorization"))
            .loginProcessingUrl("/login/oauth2/*")
            .successHandler(new MyAuthenticationSuccessHandler())
            .failureHandler(new MyAuthenticationFailureHandler())
            .addObjectPostProcessor(new ObjectPostProcessor() {
                @Override
                public extends OAuth2LoginAuthenticationFilter> O postProcess(O filter) {
                    filter.setAuthenticationResultConverter(new Converter() {
                        @Override
                        public OAuth2AuthenticationToken convert(OAuth2LoginAuthenticationToken source) {
                            OidcUser user = (OidcUser) source.getPrincipal();
                            String userName = user.getAttribute("preferred_username");
                            // 根据用户名获取适用于本系统的用户对象,用户对象同时实现UserDetails和OidcUser接口
                            UserDetails myUser = userDetailsService.loadUserByUsername(userName);
                            // 用户对象保存IdToken用于退出登录
                            // myUser.setIdToken(user.getIdToken());
                            return new OAuth2AuthenticationToken((OidcUser) myUser, myUser.getAuthorities(), source.getClientRegistration().getRegistrationId());
                        }
                    });
                    return filter;
                }
            }))
        .formLogin(formLogin -> formLogin.disable())
        .logout(logout -> logout
            .logoutUrl("/logout")
            .invalidateHttpSession(true)
            .deleteCookies("SESSION")
            .logoutSuccessHandler(this.logoutSuccessHandler()))
        .csrf(csrf -> csrf.disable());
        
        return http.build();
    }
 
    private LogoutSuccessHandler logoutSuccessHandler() {
        OidcClientInitiatedLogoutSuccessHandler handler = new OidcClientInitiatedLogoutSuccessHandler(this.clientRegistrationRepository);
        handler.setPostLogoutRedirectUri(this.clientRegistrationRepository.findByRegistrationId("my-oidc-client").getRedirectUri());
        return handler;
    }
 
    class MyAuthenticationSuccessHandler extends SimpleUrlAuthenticationSuccessHandler {
        @Override
        public void onAuthenticationSuccess(HttpServletRequest request, HttpServletResponse response, Authentication authentication) throws JsonProcessingException, IOException {
            response.setStatus(HttpServletResponse.SC_OK);
            response.setContentType("application/json;charset=UTF-8");
            // 这里自定义返回的json对象内容
            response.getWriter().write(objectMapper.writeValueAsString(authentication.getPrincipal()));
            response.getWriter().flush();
            response.getWriter().close();
        }
    }
 
    class MyAuthenticationFailureHandler extends SimpleUrlAuthenticationFailureHandler {
        @Override
        public void onAuthenticationFailure(HttpServletRequest request, HttpServletResponse response,
			AuthenticationException exception) throws IOException, ServletException {
            response.setStatus(HttpServletResponse.SC_UNAUTHORIZED);
            response.setContentType("application/json;charset=UTF-8");
            // 这里自定义返回的json对象内容
            response.getWriter().write(objectMapper.writeValueAsString(""));
            response.getWriter().flush();
            response.getWriter().close();
        }
    }
}