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10-SpringSecurity:JWT及无状态服务

目录[-]

背景

本系列教程,是作为团队内部的培训资料准备的。主要以实验的方式来体验 SpringSecurity 的各项Feature。

会话管理,是一个比较大的话题,大家熟知的Cookie-Session模式就忽略掉,今天重点介绍无状态会话:基于令牌的JWT(JSON Web Token),适用于微服务架构的会话管理方式;后续会涉及到Session共享、OAuth2.0等关于分布式集群的会话管理。

JWT简介

关于JWT的介绍,网上资源有很多,可参考:https://jwt.io/introduction,简单来说,JWT由三部分构成:Header、Payload、Signature,三者之间以点号. 分隔,前面两部分使用Base64编码(关于Base64编码的更多信息),具体构成如下:

2021-01-13-JWTParsed.png

HMACSHA256(
  base64UrlEncode(header) + "." +
  base64UrlEncode(payload),
  secret)

无状态与有状态

有状态服务,即服务端记录每次会话的客户端信息,从而识别客户端身份,根据用户身份进行相应的处理,HTTP本身是无状态的,短连接,因此便有了我们传统的Cookie-Session模式,这在单体架构中广泛使用。用户完成登录后,与用户的会话信息被保存在服务端的Session中,然后服务端响应一个SessionID给前端,前端将这个SessionID存储在Cookie中,后续请求携带Cookie信息继续发起请求,后端再查询其对应的会话信息,完成请求响应。

这种方式在微服务架构下会带来一些问题:

  1. 每建立一个会话,服务端就需要存储这个会话信息,增加了服务端存储、查询的压力,占用了宝贵的存储、计算资源;
  2. 服务端保存用户状态,难以进行水平扩展,需要在各服务器上进行状态的复制、同步(Session同步、Session共享)等处理后才能进行扩展;

明白了有状态服务,无状态服务就好理解了,无状态服务在实际比较常见的实现是采用基于令牌的方式,即:

  1. 服务端不保存任何客户端会话信息;
  2. 客户端的每次请求必须携带令牌,其中包含了认证者、签名相关信息(用户名、角色、权限等);

JWT优点、缺点

老规矩,依然采用实验的方式来进行测试,不过这次先看效果:

实验0:登录获取JWT

2021-01-13-JWTLogin.png

实验1:携带JWT:正常响应

2021-01-13-JWT200.png

实验2:未携带JWT:未认证响应

2021-01-13-JWT401.png

实验3:携带JWT:无权限响应

2021-01-13-JWT403.png

实验4:携带JWT:过期响应

2021-01-13-JWTExpired.png

实验5:携带JWT:非法格式响应

2021-01-13-JWTWrong.png

编码实现

新建一个 SpringBoot 项目,起名 springboot-security-jwt ,核心依赖为 Web , SpringSecurityjjwt

<dependencies>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-web</artifactId>
    </dependency>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-security</artifactId>
    </dependency>
    <dependency>
        <groupId>io.jsonwebtoken</groupId>
        <artifactId>jjwt</artifactId>
        <version>0.7.0</version>
    </dependency>

    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-devtools</artifactId>
        <scope>runtime</scope>
        <optional>true</optional>
    </dependency>
    <dependency>
        <groupId>org.projectlombok</groupId>
        <artifactId>lombok</artifactId>
        <optional>true</optional>
    </dependency>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-test</artifactId>
        <scope>test</scope>
    </dependency>
</dependencies>

2021-01-13-Project.png

创建资源接口: /user/add/user/query ,以及默认的home路径 / ,用以展示登录用户信息,若未登录,则展示匿名用户信息。

@RestController
@Slf4j
public class HelloController {
    @GetMapping(value = "/user/add")
    public String accessResource1() {
        return " Access Resource 1: Add User";
    }

    @GetMapping(value = "/user/query")
    public String accessResource2() {
        return " Access Resource 2: Query User";
    }

    @GetMapping(value = "/")
    public String index() {
        log.info(SecurityContextHolder.getContext().getAuthentication().toString());
        return "Welcome " + SecurityContextHolder.getContext().getAuthentication();
    }
}

安全配置类:

@Configuration
@Slf4j
public class SecurityConfig extends WebSecurityConfigurerAdapter {
    private final JwtAccessDeniedHandler jwtAccessDeniedHandler;
    private final JwtAuthenticationEntryPoint authenticationErrorHandler;

    public SecurityConfig(JwtAccessDeniedHandler jwtAccessDeniedHandler, JwtAuthenticationEntryPoint authenticationErrorHandler) {
        this.jwtAccessDeniedHandler = jwtAccessDeniedHandler;
        this.authenticationErrorHandler = authenticationErrorHandler;
    }

    @Bean
    PasswordEncoder passwordEncoder() {
        return new BCryptPasswordEncoder();
    }

    @Override
    protected void configure(AuthenticationManagerBuilder auth) throws Exception {
        // There is no PasswordEncoder mapped for the id "null"
        PasswordEncoder encoder = passwordEncoder();

        String yourPassword = "123";
        log.info("Encoded password: " + encoder.encode(yourPassword));

        // Config account info and permissions
        auth.inMemoryAuthentication()
                .withUser("dev").password(encoder.encode(yourPassword)).roles("dev", "test")
                .and()
                .withUser("test").password(encoder.encode(yourPassword)).authorities("ROLE_test");
    }

    @Override
    protected void configure(HttpSecurity http) throws Exception {
        http.authorizeRequests()
                .antMatchers("/user/add").hasRole("dev")
                .antMatchers("/user/query").hasAuthority("ROLE_test")
                .antMatchers("/user/**").authenticated()
                .anyRequest().permitAll() // Let other request pass
                .and()
                .csrf().disable() // turn off csrf, or will be 403 forbidden
                .sessionManagement()
                .sessionCreationPolicy(SessionCreationPolicy.STATELESS) // stateless
                .and()
                .formLogin()
                .successHandler(new AuthenticationSuccessHandler() {
                    @Override
                    public void onAuthenticationSuccess(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse, Authentication authentication) throws IOException {
                        log.info("Login Successfully");
                        SecurityContextHolder.getContext().setAuthentication(authentication);
                        String token = JwtUtil.createToken(authentication);
                        httpServletResponse.getWriter().write(token);
                    }
                })
                .failureHandler(new AuthenticationFailureHandler() {
                    @Override
                    public void onAuthenticationFailure(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse, AuthenticationException e) throws IOException {
                        log.info("Login Error");
                        httpServletResponse.getWriter().write(e.getLocalizedMessage());
                    }
                })
                .and()
                .addFilterBefore(new JwtAuthenticationFilter(authenticationManager()), UsernamePasswordAuthenticationFilter.class)
                .exceptionHandling()
                .authenticationEntryPoint(authenticationErrorHandler)
                .accessDeniedHandler(jwtAccessDeniedHandler);
    }
}

JWT过滤器类: JwtAuthenticationFilter

public class JwtAuthenticationFilter extends BasicAuthenticationFilter {
    public JwtAuthenticationFilter(AuthenticationManager authenticationManager) {
        super(authenticationManager);
    }
    @Override
    protected void doFilterInternal(HttpServletRequest request, HttpServletResponse response, FilterChain chain) throws IOException, ServletException {
        // 从头信息中提取token
        String token = JwtUtil.resolveToken(request);
        if (token != null) {
            // 通过JWT工具方法解析token
            Authentication authentication = JwtUtil.getAuthentication(token);
            // 将认证信息设置到上下文中,注意无状态(stateless)的设置!
            SecurityContextHolder.getContext().setAuthentication(authentication);
        }
        chain.doFilter(request, response);
    }
}

未认证、未授权拦截类: JwtAuthenticationEntryPointJwtAccessDeniedHandler

@Component
@Slf4j
public class JwtAuthenticationEntryPoint implements AuthenticationEntryPoint {
    @Override
    public void commence(HttpServletRequest request, HttpServletResponse response, AuthenticationException e) throws IOException {
        // 当用户尝试访问安全的REST资源而不提供任何凭据时,将调用此方法发送401 响应
        log.info("UNAUTHORIZED");
        response.sendError(HttpServletResponse.SC_UNAUTHORIZED, e.getMessage());
    }
}

@Component
@Slf4j
public class JwtAccessDeniedHandler implements AccessDeniedHandler {
    @Override
    public void handle(HttpServletRequest request, HttpServletResponse response, AccessDeniedException e) throws IOException {
        // 当用户在没有授权的情况下访问受保护的REST资源时,将调用此方法发送403 Forbidden响应
        log.info("FORBIDDEN");
        response.sendError(HttpServletResponse.SC_FORBIDDEN, e.getMessage());
    }
}

JWT工具类与常量类: JwtUtilJwtConstant

public class JwtUtil {
    /**
     * 生成 jwt token
     *
     * @param authentication
     * @return
     */
    public static String createToken(Authentication authentication) {
        String authorities = authentication.getAuthorities().stream()
                .map(GrantedAuthority::getAuthority)
                .collect(Collectors.joining(","));

        long now = (new Date()).getTime();
        Date validity = new Date(now + JwtConstant.VALIDITY_SECONDS * 1000);

        return Jwts.builder()
                .setSubject(authentication.getName())
                .claim(JwtConstant.AUTH_KEY, authorities)
                .signWith(SignatureAlgorithm.HS512, JwtConstant.SECRET)
                .setExpiration(validity)
                .compact();
    }

    /**
     * 解密 jwt token
     *
     * @param token
     * @return
     */
    public static Authentication getAuthentication(String token) {
        Claims claims = Jwts.parser()
                .setSigningKey(JwtConstant.SECRET)
                .parseClaimsJws(token)
                .getBody();

        Collection<? extends GrantedAuthority> authorities =
                Arrays.stream(claims.get(JwtConstant.AUTH_KEY).toString().split(","))
                        .map(SimpleGrantedAuthority::new)
                        .collect(Collectors.toList());

        User principal = new User(claims.getSubject(), "", authorities);
        return new UsernamePasswordAuthenticationToken(principal, token, authorities);
    }

    /**
     * 从请求头信息中解析出token
     *
     * @param request
     * @return
     */
    public static String resolveToken(HttpServletRequest request) {
        String bearerToken = request.getHeader(JwtConstant.HEADER);
        if (StringUtils.hasText(bearerToken) && bearerToken.startsWith(JwtConstant.TOKEN_PREFIX)) {
            return bearerToken.substring(7);
        }
        return null;
    }
}

public final class JwtConstant {
    /**
     * 对称加密密钥
     * 仅服务端存储,生产中建议使用复杂度高的密钥或采用非对称加密eg:RSA
     */
    public static final String SECRET = "heartsuit";

    /**
     * Token有效期
     */
    public static final long VALIDITY_SECONDS = 60 * 60 * 12; // default 12 hours

    /**
     * 权限
     */
    public static final String AUTH_KEY = "auth";

    /**
     * 头信息中Token的Key
     */
    public static final String HEADER = "authorization";

    /**
     * Token前缀
     */
    public static final String TOKEN_PREFIX = "Bearer ";

    private JwtConstant() {
    }
}

距离生产有多远

  1. formLogin,为了方便演示,这里有点取巧,其实无法通过浏览器表单登录了,而且当今的实际项目一般都是前后端分离的。这里在登录成功后生成JWT直接放到了 formLoginsuccessHandler 中,仅供演示。

  2. 内存方式,用户信息(用户名、密码、权限)使用简单的内存型存储;实际生产应使用数据库,方便扩展;

  3. 权限硬编码,在安全配置中,权限拦截通过手动编写;实际生产应从数据库中查询出来后动态配置;

  4. 配置常量,关于JWT的配置信息,使用了一个常量类;实际中可写到配置文件(或配置中心),通过 SpringBoot 的配置属性进行读取;

  5. 对称加密,这里采用的是对称加密方式对JWT进行签名与验签;实际生产中建议使用非对称加密算法eg: RSA 等实现;

  6. 异常拦截,关于JWT过期、格式错误的异常都是JWT依赖包自动抛出的异常,实际生产中应进行拦截并进一步封装,优化接口调用体验;

如果上述每一点占10%,那么距离上生产还有一多半的工作量要完成,因此,前面的实验或代码权当是纸上谈兵,仅用于演示,意思到了就足够了。。

注意事项

  1. 务必关闭csrf防护

.csrf().disable()

  1. 务必采用stateless方式

.sessionCreationPolicy(SessionCreationPolicy.STATELESS)

Source Code

Github

Reference


If you have any questions or any bugs are found, please feel free to contact me.

Your comments and suggestions are welcome!


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