java EE技术体系——CLF平台API开发注意事项（3）——API安全访问控制

前言：提离职了，嗯，这么多年了，真到了提离职的时候，心情真的很复杂。好吧，离职阶段需要把一些项目中的情况说明白讲清楚，这篇博客就简单说一下在平台中对API所做的安全处理（后面讲网关还要说，这里主要讲代码结构）

一、宏观概况

第一点：系统是按照Security规范，通过实现OAuth2.0协议安全控制。

关键词理解：

JWT：JWT，JWT 在前后端分离中的应用与实践

规范：Security、JAX-RS（当前选取Jersey：Difference between JAX-RS, Restlet, Jersey, RESTEasy, and Apache CXF Frameworks）

安全协议：OAuth2，参考：理解OAuth 2.0

其他：java自定义注解，RBAC，CONTAINER REQUEST FILTER

二、实现说明

2.1，安全访问过滤（重要）

在讲调用流程的时候，必须有必要说自定义的安全访问注解，云图平台的伙伴们，如果要理解系统的安全控制，或者仅是为了读接下来的流程说明，这一步很重要，一定要把这部分弄明白：  （这一段是JAX-RS规范很重要的内容）

首先看我们的自定义注解：

package com.dmsdbj.library.app.security;

import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;
import javax.ws.rs.NameBinding;

@NameBinding
@Target({ElementType.TYPE, ElementType.METHOD})
@Retention(value = RetentionPolicy.RUNTIME)
public @interface Secured {

    String[] value() default {};
}

注意里面的@NameBinding  ，请阅读：Per-JAX-RS Method Bindings   必须要明白这个@NameBinding注解是用来干嘛的！！！    

再看我们的过滤器：

@Priority(Priorities.AUTHENTICATION)
@Provider
@Secured
public class JWTAuthenticationFilter implements ContainerRequestFilter {

    @Inject
    private Logger log;

    @Inject
    private TokenProvider tokenProvider;

    @Context
    private HttpServletRequest request;

    @Context
    private ResourceInfo resourceInfo;

    @Override
    public void filter(ContainerRequestContext requestContext) throws IOException {
        String jwt = resolveToken();
        if (StringUtils.isNotBlank(jwt)) {
            try {
                if (tokenProvider.validateToken(jwt)) {
                    UserAuthenticationToken authenticationToken = this.tokenProvider.getAuthentication(jwt);
                    if (!isAllowed(authenticationToken)) {
                        requestContext.setProperty("auth-failed", true);
                        requestContext.abortWith(Response.status(Response.Status.UNAUTHORIZED).build());
                    }
                    final SecurityContext securityContext = requestContext.getSecurityContext();
                    requestContext.setSecurityContext(new SecurityContext() {
                        @Override
                        public Principal getUserPrincipal() {
                            return authenticationToken::getPrincipal;
                        }

                        @Override
                        public boolean isUserInRole(String role) {
                            return securityContext.isUserInRole(role);
                        }

                        @Override
                        public boolean isSecure() {
                            return securityContext.isSecure();
                        }

                        @Override
                        public String getAuthenticationScheme() {
                            return securityContext.getAuthenticationScheme();
                        }
                    });
                }
            } catch (ExpiredJwtException eje) {
                log.info("Security exception for user {} - {}", eje.getClaims().getSubject(), eje.getMessage());
                requestContext.setProperty("auth-failed", true);
                requestContext.abortWith(Response.status(Response.Status.UNAUTHORIZED).build());
            }

        } else {
            log.info("No JWT token found");
            requestContext.setProperty("auth-failed", true);
            requestContext.abortWith(Response.status(Response.Status.UNAUTHORIZED).build());
        }

    }

    private String resolveToken() {
        String bearerToken = request.getHeader(Constants.AUTHORIZATION_HEADER);
        if (StringUtils.isNotEmpty(bearerToken) && bearerToken.startsWith("Bearer ")) {
            String jwt = bearerToken.substring(7, bearerToken.length());
            return jwt;
        }
        return null;
    }

    private boolean isAllowed(UserAuthenticationToken authenticationToken) {
        Secured secured = resourceInfo.getResourceMethod().getAnnotation(Secured.class);
        if (secured == null) {
            secured = resourceInfo.getResourceClass().getAnnotation(Secured.class);
        }
        for (String role : secured.value()) {
            if (!authenticationToken.getAuthorities().contains(role)) {
                return false;
            }
        }
        return true;
    }
}

附：1，You can bind a filter or interceptor to a particular annotation and when that custom annotation is applied, the filter or interceptor will automatically be bound to the annotated JAX-RS method.      （文章：Per-JAX-RS Method Bindings ）

  2，By default, i.e. if no name binding is applied to the filter implementation class, the filter instance is applied globally, however only after the incoming request has been matched to a particular resource by JAX-RS runtime. If there is a @NameBinding annotation applied to the filter, the filter will also be executed at the post-match request extension point, but only in case the matched resource or sub-resource method is bound to the same name-binding annotation. （文章：CONTAINER REQUEST FILTER）

简单说来：这个本应该用于所有请求过滤的过滤器，因为加上了@Secure的注解（而@Secure注解又加上了@NameBinding注解），所以，这个过滤器仅被用于有@Secure修饰的特定类、方法！  备注：当前过滤器执行后匹配模式@Provider

2.2，正常访问流程

由上述的过滤器说明，要想请求经过安全限制的API（有@Seured修饰），必须要得到一个可用的token信息（resolveToken方法）。

所以，第一步通过登录获取票据：

服务端：

调用login方法（UserJWTController）

   @Timed
    @ApiOperation(value = "authenticate the credential")
    @ApiResponses(value = {
        @ApiResponse(code = 200, message = "OK")
        ,
        @ApiResponse(code = 401, message = "Unauthorized")})
    @Path("/authenticate")
    @POST
    @Consumes({MediaType.APPLICATION_JSON})
    @Produces({MediaType.APPLICATION_JSON})
    public Response login(@Valid LoginDTO loginDTO) throws ServletException {

        UserAuthenticationToken authenticationToken = new UserAuthenticationToken(loginDTO.getUsername(), loginDTO.getPassword());

        try {
            User user = userService.authenticate(authenticationToken);
            boolean rememberMe = (loginDTO.isRememberMe() == null) ? false : loginDTO.isRememberMe();
            String jwt = tokenProvider.createToken(user, rememberMe);
            return Response.ok(new JWTToken(jwt)).header(Constants.AUTHORIZATION_HEADER, "Bearer " + jwt).build();
        } catch (AuthenticationException exception) {
            return Response.status(Status.UNAUTHORIZED).header("AuthenticationException", exception.getLocalizedMessage()).build();
        }
    }

A：调用了userService.authenticate(authenticationToken)，根据当前登录用户，查询用户信息及其角色信息；B：调用tokenProvider.createToken(user, rememberMe)，为当前用户生成一个访问票据；C：将当前的票据信息存入到响应header。

客户端：

客户端接收到请求login方法后的Response，会从中提取票据token，并存入localStorage。本系统的具体代码位置：qpp/services/quth/auth.jwt.service  附：HTML 5 Web 存储

API请求：

在第一次登录获取完票据后，后续的请求，当请求的API有自定义注解@Secured时，经过过滤器，首先解析JWT判断是否拥有访问权限，再判断是否允许访问！

附：关键类TokenProvider

package com.dmsdbj.library.app.security.jwt;

import com.dmsdbj.library.app.config.SecurityConfig;
import com.dmsdbj.library.app.security.UserAuthenticationToken;
import com.dmsdbj.library.entity.User;
import java.util.*;
import java.util.stream.Collectors;
import javax.annotation.PostConstruct;
import javax.inject.Inject;
import org.slf4j.Logger;
import io.jsonwebtoken.*;

public class TokenProvider {

    @Inject
    private Logger log;

    private static final String AUTHORITIES_KEY = "auth";

    private String secretKey;

    private long tokenValidityInSeconds;

    private long tokenValidityInSecondsForRememberMe;

    @Inject
    private SecurityConfig securityConfig;

    @PostConstruct
    public void init() {
        this.secretKey
                = securityConfig.getSecret();

        this.tokenValidityInSeconds
                = 1000 * securityConfig.getTokenValidityInSeconds();
        this.tokenValidityInSecondsForRememberMe
                = 1000 * securityConfig.getTokenValidityInSecondsForRememberMe();
    }

    public String createToken(User user, Boolean rememberMe) {
        String authorities = user.getAuthorities().stream()
                .map(authority -> authority.getName())
                .collect(Collectors.joining(","));

        long now = (new Date()).getTime();
        Date validity;
        if (rememberMe) {
            validity = new Date(now + this.tokenValidityInSecondsForRememberMe);
        } else {
            validity = new Date(now + this.tokenValidityInSeconds);
        }

        return Jwts.builder()
                .setSubject(user.getLogin())
                .claim(AUTHORITIES_KEY, authorities)
                .signWith(SignatureAlgorithm.HS512, secretKey)
                .setExpiration(validity)
                .compact();
    }

    public UserAuthenticationToken getAuthentication(String token) {
        Claims claims = Jwts.parser()
                .setSigningKey(secretKey)
                .parseClaimsJws(token)
                .getBody();

        Set<String> authorities
                = Arrays.asList(claims.get(AUTHORITIES_KEY).toString().split(",")).stream()
                        .collect(Collectors.toSet());

        return new UserAuthenticationToken(claims.getSubject(), "", authorities);
    }

    public boolean validateToken(String authToken) {
        try {
            Jwts.parser().setSigningKey(secretKey).parseClaimsJws(authToken);
            return true;
        } catch (SignatureException e) {
            log.info("Invalid JWT signature: " + e.getMessage());
            return false;
        }
    }
}

三、总结

关于本平台的基本安全访问控制，大概就这些内容。其实挺简单的，就是模拟了一个票据生成中心，然后使用了JWT省去了读取服务器端session的步骤，仅通过解析JWT票据进行授权。    嗯，尽可能的在说明白，如果还是不明白的话，小伙伴们及时找我交流（先做任务，不然扛把子该......）

在本项目中涉及到的类：