Spring Cloud Gateway：过滤器

本文主要介绍Spring Cloud Gateway过滤器全家桶，GlobalFilter局过滤器接口与 GatewayFilter 网关过滤器接口具有相同的方法定义，全局过滤器是一系列特殊的过滤器，会根据条件应用到所有路由中。网关过滤器是更细粒度的过滤器，作用于指定的路由中。

网关鉴权

通过自定义过滤器 AuthFilter 实现 GlobalFilter 实现网关鉴权：

/**
 * 网关鉴权
 *
 * @author jacklin
 */
@Component
public class AuthFilter implements GlobalFilter, Ordered {

    private static final Logger log = LoggerFactory.getLogger(AuthFilter.class);

    // 排除过滤的 uri 地址，nacos自行添加
    @Autowired
    private IgnoreWhiteProperties ignoreWhite;

    @Autowired
    private RedisService redisService;


    @Override
    public Mono<Void> filter(ServerWebExchange exchange, GatewayFilterChain chain) {
        ServerHttpRequest request = exchange.getRequest();
        ServerHttpRequest.Builder mutate = request.mutate();

        String url = request.getURI().getPath();
        // 跳过不需要验证的路径
        if (StringUtils.matches(url, ignoreWhite.getWhites())) {
            return chain.filter(exchange);
        }
        String token = getToken(request);
        if (StringUtils.isEmpty(token)) {
            return unauthorizedResponse(exchange, "令牌不能为空");
        }
        Claims claims = JwtUtils.parseToken(token);
        if (claims == null) {
            return unauthorizedResponse(exchange, "令牌已过期或验证不正确！");
        }
        String userkey = JwtUtils.getUserKey(claims);
        boolean islogin = redisService.hasKey(getTokenKey(userkey));
        if (!islogin) {
            return unauthorizedResponse(exchange, "登录状态已过期");
        }
        String userid = JwtUtils.getUserId(claims);
        String username = JwtUtils.getUserName(claims);
        if (StringUtils.isEmpty(userid) || StringUtils.isEmpty(username)) {
            return unauthorizedResponse(exchange, "令牌验证失败");
        }

        // 设置用户信息到请求
        addHeader(mutate, SecurityConstants.USER_KEY, userkey);
        addHeader(mutate, SecurityConstants.DETAILS_USER_ID, userid);
        addHeader(mutate, SecurityConstants.DETAILS_USERNAME, username);
        // 内部请求来源参数清除
        removeHeader(mutate, SecurityConstants.FROM_SOURCE);
        return chain.filter(exchange.mutate().request(mutate.build()).build());
    }

    private void addHeader(ServerHttpRequest.Builder mutate, String name, Object value) {
        if (value == null) {
            return;
        }
        String valueStr = value.toString();
        String valueEncode = ServletUtils.urlEncode(valueStr);
        mutate.header(name, valueEncode);
    }

    private void removeHeader(ServerHttpRequest.Builder mutate, String name) {
        mutate.headers(httpHeaders -> httpHeaders.remove(name)).build();
    }

    private Mono<Void> unauthorizedResponse(ServerWebExchange exchange, String msg) {
        log.error("[鉴权异常处理]请求路径:{}", exchange.getRequest().getPath());
        return ServletUtils.webFluxResponseWriter(exchange.getResponse(), msg, HttpStatus.UNAUTHORIZED);
    }

    /**
     * 获取缓存key
     */
    private String getTokenKey(String token) {
        return CacheConstants.LOGIN_TOKEN_KEY + token;
    }

    /**
     * 获取请求token
     */
    private String getToken(ServerHttpRequest request) {
        String token = request.getHeaders().getFirst(TokenConstants.AUTHENTICATION);
        // 如果前端设置了令牌前缀，则裁剪掉前缀
        if (StringUtils.isNotEmpty(token) && token.startsWith(TokenConstants.PREFIX)) {
            token = token.replaceFirst(TokenConstants.PREFIX, StringUtils.EMPTY);
        }
        return token;
    }

    @Override
    public int getOrder() {
        return -200;
    }
}