Spring Cloud Gateway：過濾器

本文主要介紹Spring Cloud Gateway過濾器全家桶，GlobalFilter局過濾器接口與 GatewayFilter 網關過濾器接口具有相同的方法定義，全局過濾器是一系列特殊的過濾器，會根據條件應用到所有路由中。網關過濾器是更細粒度的過濾器，作用於指定的路由中。

網關鑑權

通過自定義過濾器 AuthFilter 實現 GlobalFilter 實現網關鑑權：

/**
 * 網關鑑權
 *
 * @author jacklin
 */
@Component
public class AuthFilter implements GlobalFilter, Ordered {

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

    // 排除過濾的 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();
        // 跳過不需要驗證的路徑
        if (StringUtils.matches(url, ignoreWhite.getWhites())) {
            return chain.filter(exchange);
        }
        String token = getToken(request);
        if (StringUtils.isEmpty(token)) {
            return unauthorizedResponse(exchange, "令牌不能爲空");
        }
        Claims claims = JwtUtils.parseToken(token);
        if (claims == null) {
            return unauthorizedResponse(exchange, "令牌已過期或驗證不正確！");
        }
        String userkey = JwtUtils.getUserKey(claims);
        boolean islogin = redisService.hasKey(getTokenKey(userkey));
        if (!islogin) {
            return unauthorizedResponse(exchange, "登錄狀態已過期");
        }
        String userid = JwtUtils.getUserId(claims);
        String username = JwtUtils.getUserName(claims);
        if (StringUtils.isEmpty(userid) || StringUtils.isEmpty(username)) {
            return unauthorizedResponse(exchange, "令牌驗證失敗");
        }

        // 設置用戶信息到請求
        addHeader(mutate, SecurityConstants.USER_KEY, userkey);
        addHeader(mutate, SecurityConstants.DETAILS_USER_ID, userid);
        addHeader(mutate, SecurityConstants.DETAILS_USERNAME, username);
        // 內部請求來源參數清除
        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("[鑑權異常處理]請求路徑:{}", exchange.getRequest().getPath());
        return ServletUtils.webFluxResponseWriter(exchange.getResponse(), msg, HttpStatus.UNAUTHORIZED);
    }

    /**
     * 獲取緩存key
     */
    private String getTokenKey(String token) {
        return CacheConstants.LOGIN_TOKEN_KEY + token;
    }

    /**
     * 獲取請求token
     */
    private String getToken(ServerHttpRequest request) {
        String token = request.getHeaders().getFirst(TokenConstants.AUTHENTICATION);
        // 如果前端設置了令牌前綴，則裁剪掉前綴
        if (StringUtils.isNotEmpty(token) && token.startsWith(TokenConstants.PREFIX)) {
            token = token.replaceFirst(TokenConstants.PREFIX, StringUtils.EMPTY);
        }
        return token;
    }

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