自定义Filter

说明

  • 本文介绍如何对 org.springframework.web.server.WebFliter 进行扩展。

跨域支持

  • 新增 org.apache.shenyu.web.filter.CrossFilter 实现 WebFilter。
  1.  public class CrossFilter implements WebFilter {
  4.      private static final String ALLOWED_HEADERS = "x-requested-with, authorization, Content-Type, Authorization, credential, X-XSRF-TOKEN,token,username,client";
  7.      private static final String ALLOWED_METHODS = "*";
  10.      private static final String ALLOWED_ORIGIN = "*";
  13.      private static final String ALLOWED_EXPOSE = "*";
  16.      private static final String MAX_AGE = "18000";
  19.      @Override
  20.      @SuppressWarnings("all")
  21.      public Mono<Void> filter(final ServerWebExchange exchange, final WebFilterChain chain) {
  22.          ServerHttpRequest request = exchange.getRequest();
  23.          if (CorsUtils.isCorsRequest(request)) {
  24.              ServerHttpResponse response = exchange.getResponse();
  25.              HttpHeaders headers = response.getHeaders();
  26.              headers.add("Access-Control-Allow-Origin", ALLOWED_ORIGIN);
  27.              headers.add("Access-Control-Allow-Methods", ALLOWED_METHODS);
  28.              headers.add("Access-Control-Max-Age", MAX_AGE);
  29.              headers.add("Access-Control-Allow-Headers", ALLOWED_HEADERS);
  30.              headers.add("Access-Control-Expose-Headers", ALLOWED_EXPOSE);
  31.              headers.add("Access-Control-Allow-Credentials", "true");
  32.              if (request.getMethod() == HttpMethod.OPTIONS) {
  33.                  response.setStatusCode(HttpStatus.OK);
  34.                  return Mono.empty();
  35.              }
  36.          }
  37.          return chain.filter(exchange);
  38.      }
  39.  }
  • 将 CrossFilter 注册成为 Spring的bean。

网关过滤 springboot健康检查

  • 注意顺序，使用 @Order 注解
  1. @Component
  2. @Order(-99)
  3. public final class HealthFilter implements WebFilter {
  6.     private static final String[] FILTER_TAG = {"/actuator/health", "/health_check"};
  9.     @Override
  10.     public Mono<Void> filter(@Nullable final ServerWebExchange exchange, @Nullable final WebFilterChain chain) {
  11.         ServerHttpRequest request = Objects.requireNonNull(exchange).getRequest();
  12.         String urlPath = request.getURI().getPath();
  13.         for (String check : FILTER_TAG) {
  14.             if (check.equals(urlPath)) {
  15.                 String result = JsonUtils.toJson(new Health.Builder().up().build());
  16.                 DataBuffer dataBuffer = exchange.getResponse().bufferFactory().wrap(result.getBytes());
  17.                 return exchange.getResponse().writeWith(Mono.just(dataBuffer));
  18.             }
  19.         }
  20.         return Objects.requireNonNull(chain).filter(exchange);
  21.     }
  22. }

继承 org.apache.shenyu.web.filter.AbstractWebFilter

  • 新增一个类继承AbstractWebFilter，并实现它的两个方法。
  1.    /**
  2.      * this is Template Method ,children Implement your own filtering logic.
  3.      *
  4.      * @param exchange the current server exchange
  5.      * @param chain    provides a way to delegate to the next filter
  6.      * @return {@code Mono<Boolean>} result：TRUE (is pass)，and flow next filter；FALSE (is not pass) execute doDenyResponse(ServerWebExchange exchange)
  7.      */
  8.     protected abstract Mono<Boolean> doFilter(ServerWebExchange exchange, WebFilterChain chain);
  11.     /**
  12.      * this is Template Method ,children Implement your own And response client.
  13.      *
  14.      * @param exchange the current server exchange.
  15.      * @return {@code Mono<Void>} response msg.
  16.      */
  17.     protected abstract Mono<Void> doDenyResponse(ServerWebExchange exchange);
  • doFilter 方法返回 Mono<true> 表示通过，反之则不通过，不通过的时候，会调用 doDenyResponse输出相关信息到前端。