一、背景

随着我们的微服务越来越多，如果每个微服务都要自己去实现一套鉴权操作，那么这么操作比较冗余，因此我们可以把鉴权操作统一放到网关去做，如果微服务自己有额外的鉴权处理，可以在自己的微服务中处理。

二、需求

1、在网关层完成url层面的鉴权操作。

所有的OPTION请求都放行。
所有不存在请求，直接都拒绝访问。
user-provider服务的findAllUsers需要 user.userInfo权限才可以访问。

2、将解析后的jwt token当做请求头传递到下游服务中。
3、整合Spring Security Oauth2 Resource Server

三、前置条件

1、搭建一个可用的认证服务器，可以参考之前的文章.
2、知道Spring Security Oauth2 Resource Server资源服务器如何使用，可以参考之前的文章.

四、项目结构

五、网关层代码的编写

1、引入jar包

<dependency>
    <groupId>com.alibaba.cloud</groupId>
    <artifactId>spring-cloud-starter-alibaba-nacos-discovery</artifactId>
</dependency>
<dependency>
    <groupId>org.springframework.cloud</groupId>
    <artifactId>spring-cloud-starter-gateway</artifactId>
</dependency>
<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-oauth2-resource-server</artifactId>
</dependency>
<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-security</artifactId>
</dependency>
<dependency>
    <groupId>org.springframework.cloud</groupId>
    <artifactId>spring-cloud-starter-loadbalancer</artifactId>
</dependency>

2、自定义授权管理器

自定义授权管理器，判断用户是否有权限访问
此处我们简单判断
1、放行所有的 OPTION 请求。
2、判断某个请求(url)用户是否有权限访问。
3、所有不存在的请求(url)直接无权限访问。

package com.huan.study.gateway.config;

import com.google.common.collect.Maps;
import lombok.extern.slf4j.Slf4j;
import org.springframework.http.HttpMethod;
import org.springframework.http.server.reactive.ServerHttpRequest;
import org.springframework.security.authentication.AbstractAuthenticationToken;
import org.springframework.security.authorization.AuthorizationDecision;
import org.springframework.security.authorization.ReactiveAuthorizationManager;
import org.springframework.security.core.Authentication;
import org.springframework.security.core.GrantedAuthority;
import org.springframework.security.oauth2.server.resource.authentication.JwtAuthenticationToken;
import org.springframework.security.web.server.authorization.AuthorizationContext;
import org.springframework.stereotype.Component;
import org.springframework.util.AntPathMatcher;
import org.springframework.util.PathMatcher;
import org.springframework.util.StringUtils;
import org.springframework.web.server.ServerWebExchange;
import reactor.core.publisher.Mono;

import javax.annotation.PostConstruct;
import java.util.Map;
import java.util.Objects;

/**
 * 自定义授权管理器，判断用户是否有权限访问
 *
 * @author huan.fu 2021/8/24 - 上午9:57
 */
@Component
@Slf4j
public class CustomReactiveAuthorizationManager implements ReactiveAuthorizationManager<AuthorizationContext> {

    /**
     * 此处保存的是资源对应的权限，可以从数据库中获取
     */
    private static final Map<String, String> AUTH_MAP = Maps.newConcurrentMap();

    @PostConstruct
    public void initAuthMap() {
        AUTH_MAP.put("/user/findAllUsers", "user.userInfo");
        AUTH_MAP.put("/user/addUser", "ROLE_ADMIN");
    }


    @Override
    public Mono<AuthorizationDecision> check(Mono<Authentication> authentication, AuthorizationContext authorizationContext) {
        ServerWebExchange exchange = authorizationContext.getExchange();
        ServerHttpRequest request = exchange.getRequest();
        String path = request.getURI().getPath();

        // 带通配符的可以使用这个进行匹配
        PathMatcher pathMatcher = new AntPathMatcher();
        String authorities = AUTH_MAP.get(path);
        log.info("访问路径:[{}],所需要的权限是:[{}]", path, authorities);

        // option 请求，全部放行
        if (request.getMethod() == HttpMethod.OPTIONS) {
            return Mono.just(new AuthorizationDecision(true));
        }

        // 不在权限范围内的url，全部拒绝
        if (!StringUtils.hasText(authorities)) {
            return Mono.just(new AuthorizationDecision(false));
        }

        return authentication
                .filter(Authentication::isAuthenticated)
                .filter(a -> a instanceof JwtAuthenticationToken)
                .cast(JwtAuthenticationToken.class)
                .doOnNext(token -> {
                    System.out.println(token.getToken().getHeaders());
                    System.out.println(token.getTokenAttributes());
                })
                .flatMapIterable(AbstractAuthenticationToken::getAuthorities)
                .map(GrantedAuthority::getAuthority)
                .any(authority -> Objects.equals(authority, authorities))
                .map(AuthorizationDecision::new)
                .defaultIfEmpty(new AuthorizationDecision(false));
    }
}

3、token认证失败、或超时的处理

package com.huan.study.gateway.config;

import org.springframework.core.io.buffer.DataBuffer;
import org.springframework.core.io.buffer.DataBufferUtils;
import org.springframework.http.HttpStatus;
import org.springframework.security.core.AuthenticationException;
import org.springframework.security.web.server.ServerAuthenticationEntryPoint;
import org.springframework.web.server.ServerWebExchange;
import reactor.core.publisher.Mono;

import java.nio.charset.StandardCharsets;

/**
 * 认证失败异常处理
 *
 * @author huan.fu 2021/8/25 - 下午1:10
 */
public class CustomServerAuthenticationEntryPoint implements ServerAuthenticationEntryPoint {
    @Override
    public Mono<Void> commence(ServerWebExchange exchange, AuthenticationException ex) {

        return Mono.defer(() -> Mono.just(exchange.getResponse()))
                .flatMap(response -> {
                    response.setStatusCode(HttpStatus.UNAUTHORIZED);
                    String body = "{\"code\":401,\"msg\":\"token不合法或过期\"}";
                    DataBuffer buffer = response.bufferFactory().wrap(body.getBytes(StandardCharsets.UTF_8));
                    return response.writeWith(Mono.just(buffer))
                            .doOnError(error -> DataBufferUtils.release(buffer));
                });
    }
}

4、用户没有权限的处理

package com.huan.study.gateway.config;

import lombok.extern.slf4j.Slf4j;
import org.springframework.context.annotation.Bean;
import org.springframework.core.io.buffer.DataBuffer;
import org.springframework.core.io.buffer.DataBufferUtils;
import org.springframework.http.HttpStatus;
import org.springframework.http.server.reactive.ServerHttpRequest;
import org.springframework.http.server.reactive.ServerHttpResponse;
import org.springframework.security.access.AccessDeniedException;
import org.springframework.security.web.server.authorization.ServerAccessDeniedHandler;
import org.springframework.web.server.ServerWebExchange;
import reactor.core.publisher.Mono;

import java.nio.charset.StandardCharsets;

/**
 * 无权限访问异常
 *
 * @author huan.fu 2021/8/25 - 下午12:18
 */
@Slf4j
public class CustomServerAccessDeniedHandler implements ServerAccessDeniedHandler {

    @Override
    public Mono<Void> handle(ServerWebExchange exchange, AccessDeniedException denied) {

        ServerHttpRequest request = exchange.getRequest();

        return exchange.getPrincipal()
                .doOnNext(principal -> log.info("用户:[{}]没有访问:[{}]的权限.", principal.getName(), request.getURI()))
                .flatMap(principal -> {
                    ServerHttpResponse response = exchange.getResponse();
                    response.setStatusCode(HttpStatus.FORBIDDEN);
                    String body = "{\"code\":403,\"msg\":\"您无权限访问\"}";
                    DataBuffer buffer = response.bufferFactory().wrap(body.getBytes(StandardCharsets.UTF_8));
                    return response.writeWith(Mono.just(buffer))
                            .doOnError(error -> DataBufferUtils.release(buffer));
                });
    }
}

5、将token信息传递到下游服务器中

package com.huan.study.gateway.config;

import com.fasterxml.jackson.core.JsonProcessingException;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.datatype.jdk8.Jdk8Module;
import com.fasterxml.jackson.datatype.jsr310.JavaTimeModule;
import org.springframework.http.server.reactive.ServerHttpRequest;
import org.springframework.security.core.context.ReactiveSecurityContextHolder;
import org.springframework.security.core.context.SecurityContext;
import org.springframework.security.oauth2.server.resource.authentication.JwtAuthenticationToken;
import org.springframework.web.server.ServerWebExchange;
import org.springframework.web.server.WebFilter;
import org.springframework.web.server.WebFilterChain;
import reactor.core.publisher.Mono;

/**
 * 将token信息传递到下游服务中
 *
 * @author huan.fu 2021/8/25 - 下午2:49
 */
public class TokenTransferFilter implements WebFilter {

    private static final ObjectMapper OBJECT_MAPPER = new ObjectMapper();

    static {
        OBJECT_MAPPER.registerModule(new Jdk8Module());
        OBJECT_MAPPER.registerModule(new JavaTimeModule());
    }

    @Override
    public Mono<Void> filter(ServerWebExchange exchange, WebFilterChain chain) {
        return ReactiveSecurityContextHolder.getContext()
                .map(SecurityContext::getAuthentication)
                .cast(JwtAuthenticationToken.class)
                .flatMap(authentication -> {
                    ServerHttpRequest request = exchange.getRequest();
                    request = request.mutate()
                            .header("tokenInfo", toJson(authentication.getPrincipal()))
                            .build();

                    ServerWebExchange newExchange = exchange.mutate().request(request).build();

                    return chain.filter(newExchange);
                });
    }

    public String toJson(Object obj) {
        try {
            return OBJECT_MAPPER.writeValueAsString(obj);
        } catch (JsonProcessingException e) {
            return null;
        }
    }
}

6、网关层面的配置

package com.huan.study.gateway.config;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.core.convert.converter.Converter;
import org.springframework.core.io.FileSystemResource;
import org.springframework.core.io.Resource;
import org.springframework.security.authentication.AbstractAuthenticationToken;
import org.springframework.security.config.annotation.web.reactive.EnableWebFluxSecurity;
import org.springframework.security.config.web.server.SecurityWebFiltersOrder;
import org.springframework.security.config.web.server.ServerHttpSecurity;
import org.springframework.security.oauth2.jose.jws.SignatureAlgorithm;
import org.springframework.security.oauth2.jwt.Jwt;
import org.springframework.security.oauth2.jwt.NimbusReactiveJwtDecoder;
import org.springframework.security.oauth2.jwt.ReactiveJwtDecoder;
import org.springframework.security.oauth2.server.resource.authentication.JwtAuthenticationConverter;
import org.springframework.security.oauth2.server.resource.authentication.JwtGrantedAuthoritiesConverter;
import org.springframework.security.oauth2.server.resource.authentication.ReactiveJwtAuthenticationConverterAdapter;
import org.springframework.security.oauth2.server.resource.web.server.ServerBearerTokenAuthenticationConverter;
import org.springframework.security.web.server.SecurityWebFilterChain;
import reactor.core.publisher.Mono;

import java.io.IOException;
import java.nio.file.Files;
import java.security.KeyFactory;
import java.security.NoSuchAlgorithmException;
import java.security.interfaces.RSAPublicKey;
import java.security.spec.InvalidKeySpecException;
import java.security.spec.X509EncodedKeySpec;
import java.util.Base64;

/**
 * 资源服务器配置
 *
 * @author huan.fu 2021/8/24 - 上午10:08
 */
@Configuration
@EnableWebFluxSecurity
public class ResourceServerConfig {

    @Autowired
    private CustomReactiveAuthorizationManager customReactiveAuthorizationManager;

    @Bean
    public SecurityWebFilterChain securityWebFilterChain(ServerHttpSecurity http) throws NoSuchAlgorithmException, IOException, InvalidKeySpecException {
        http.oauth2ResourceServer()
                .jwt()
                    .jwtAuthenticationConverter(jwtAuthenticationConverter())
                    .jwtDecoder(jwtDecoder())
                    .and()
                // 认证成功后没有权限操作
                .accessDeniedHandler(new CustomServerAccessDeniedHandler())
                // 还没有认证时发生认证异常，比如token过期，token不合法
                .authenticationEntryPoint(new CustomServerAuthenticationEntryPoint())
                // 将一个字符串token转换成一个认证对象
                .bearerTokenConverter(new ServerBearerTokenAuthenticationConverter())
                    .and()
        .authorizeExchange()
                // 所有以 /auth/** 开头的请求全部放行
                .pathMatchers("/auth/**", "/favicon.ico").permitAll()
                // 所有的请求都交由此处进行权限判断处理
                .anyExchange()
                    .access(customReactiveAuthorizationManager)
                    .and()
                .exceptionHandling()
                    .accessDeniedHandler(new CustomServerAccessDeniedHandler())
                    .authenticationEntryPoint(new CustomServerAuthenticationEntryPoint())
                    .and()
                .csrf()
                    .disable()
        .addFilterAfter(new TokenTransferFilter(), SecurityWebFiltersOrder.AUTHENTICATION);

        return http.build();
    }

    /**
     * 从jwt令牌中获取认证对象
     */
    public Converter<Jwt, ? extends Mono<? extends AbstractAuthenticationToken>> jwtAuthenticationConverter() {

        // 从jwt 中获取该令牌可以访问的权限
        JwtGrantedAuthoritiesConverter authoritiesConverter = new JwtGrantedAuthoritiesConverter();
        // 取消权限的前缀，默认会加上SCOPE_
        authoritiesConverter.setAuthorityPrefix("");
        // 从那个字段中获取权限
        authoritiesConverter.setAuthoritiesClaimName("scope");

        JwtAuthenticationConverter jwtAuthenticationConverter = new JwtAuthenticationConverter();
        // 获取 principal name
        jwtAuthenticationConverter.setPrincipalClaimName("sub");
        jwtAuthenticationConverter.setJwtGrantedAuthoritiesConverter(authoritiesConverter);

        return new ReactiveJwtAuthenticationConverterAdapter(jwtAuthenticationConverter);
    }

    /**
     * 解码jwt
     */
    public ReactiveJwtDecoder jwtDecoder() throws IOException, NoSuchAlgorithmException, InvalidKeySpecException {
        Resource resource = new FileSystemResource("/Users/huan/code/study/idea/spring-cloud-alibaba-parent/gateway-oauth2/new-authoriza-server-public-key.pem");
        String publicKeyStr = String.join("", Files.readAllLines(resource.getFile().toPath()));
        byte[] publicKeyBytes = Base64.getDecoder().decode(publicKeyStr);
        X509EncodedKeySpec keySpec = new X509EncodedKeySpec(publicKeyBytes);
        KeyFactory keyFactory = KeyFactory.getInstance("RSA");
        RSAPublicKey rsaPublicKey = (RSAPublicKey) keyFactory.generatePublic(keySpec);

        return NimbusReactiveJwtDecoder.withPublicKey(rsaPublicKey)
                .signatureAlgorithm(SignatureAlgorithm.RS256)
                .build();
    }
}

7、网关yaml配置文件

spring:
  application:
    name: gateway-auth
  cloud:
    nacos:
      discovery:
        server-addr: localhost:8847
    gateway:
      routes:
        - id: user-provider
          uri: lb://user-provider
          predicates:
            - Path=/user/**
          filters:
            - RewritePath=/user(?<segment>/?.*), $\{segment}
    compatibility-verifier:
      # 取消SpringCloud SpringCloudAlibaba SpringBoot 等的版本检查
      enabled: false
server:
  port: 9203
debug: true

六、演示

1、客户端 gateway 在认证服务器拥有的权限为 user.userInfo

2、user-provider服务提供了一个api findAllUsers，它会返回系统中存在的用户(假的数据) 和解码后的token信息。

3、在网关层面，findAllUsers 需要的权限为 user.userInfo，正好 gateway这个客户端有这个权限，所以可以访问。

七、代码路径

Spring Cloud Alibaba: Spring Cloud Alibaba 学习 - Gitee.com

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Spring Cloud Gateway + Jwt + Oauth2 实现网关的鉴权操作