全局过滤器作用于一切的路由,不须要零丁设置,我们能够用它来完成许多统一化处置惩罚的营业需求,比方权限认证,IP接见限定等等。
接口定义类:org.springframework.cloud.gateway.filter.GlobalFilter
public interface GlobalFilter { Mono<Void> filter(ServerWebExchange exchange, GatewayFilterChain chain); }
gateway自带的GlobalFilter完成类有许多,如下图:
有转发,路由,负载等相干的GlobalFilter,感兴趣的能够本身去看下源码,了解下。
我们本身怎样定义GlobalFilter来完成我们本身的营业逻辑?
给出一个官方文档上的案例:
@Configuration public class ExampleConfiguration { private Logger log = LoggerFactory.getLogger(ExampleConfiguration.class); @Bean @Order(-1) public GlobalFilter a() { return (exchange, chain) -> { log.info("first pre filter"); return chain.filter(exchange).then(Mono.fromRunnable(() -> { log.info("third post filter"); })); }; } @Bean @Order(0) public GlobalFilter b() { return (exchange, chain) -> { log.info("second pre filter"); return chain.filter(exchange).then(Mono.fromRunnable(() -> { log.info("second post filter"); })); }; } @Bean @Order(1) public GlobalFilter c() { return (exchange, chain) -> { log.info("third pre filter"); return chain.filter(exchange).then(Mono.fromRunnable(() -> { log.info("first post filter"); })); }; } }
上面定义了3个GlobalFilter,经由过程@Order来指定实行的递次,数字越小,优先级越高。下面就是输出的日记,从日记就能够看出实行的递次:
2018-10-14 12:08:52.406 INFO 55062 --- [ioEventLoop-4-1] c.c.gateway.config.ExampleConfiguration : first pre filter 2018-10-14 12:08:52.406 INFO 55062 --- [ioEventLoop-4-1] c.c.gateway.config.ExampleConfiguration : second pre filter 2018-10-14 12:08:52.407 INFO 55062 --- [ioEventLoop-4-1] c.c.gateway.config.ExampleConfiguration : third pre filter 2018-10-14 12:08:52.437 INFO 55062 --- [ctor-http-nio-7] c.c.gateway.config.ExampleConfiguration : first post filter 2018-10-14 12:08:52.438 INFO 55062 --- [ctor-http-nio-7] c.c.gateway.config.ExampleConfiguration : second post filter 2018-10-14 12:08:52.438 INFO 55062 --- [ctor-http-nio-7] c.c.gateway.config.ExampleConfiguration : third post filter
当GlobalFilter的逻辑比较多时,我照样引荐人人零丁写一个GlobalFilter来处置惩罚,比方我们要完成对IP的接见限定,不在IP白名单中就不让挪用的需求。
零丁定义只须要完成GlobalFilter, Ordered这两个接口就能够了。
@Component public class IPCheckFilter implements GlobalFilter, Ordered { @Override public int getOrder() { return 0; } @Override public Mono<Void> filter(ServerWebExchange exchange, GatewayFilterChain chain) { HttpHeaders headers = exchange.getRequest().getHeaders(); // 此处写死了,演示用,现实中须要采用设置的体式格局 if (getIp(headers).equals("127.0.0.1")) { ServerHttpResponse response = exchange.getResponse(); ResponseData data = new ResponseData(); data.setCode(401); data.setMessage("不法要求"); byte[] datas = JsonUtils.toJson(data).getBytes(StandardCharsets.UTF_8); DataBuffer buffer = response.bufferFactory().wrap(datas); response.setStatusCode(HttpStatus.UNAUTHORIZED); response.getHeaders().add("Content-Type", "application/json;charset=UTF-8"); return response.writeWith(Mono.just(buffer)); } return chain.filter(exchange); } // 这边从要求头中猎取用户的现实IP,依据Nginx转发的要求头猎取 private String getIp(HttpHeaders headers) { return "127.0.0.1"; } }
过滤的运用没什么好讲的,都比较简单,作用却很大,能够处置惩罚许多需求,上面讲的IP认证阻拦只是冰山一角,更多的功用须要我们本身基于过滤器去完成。
比方我想做a/b测试,那末就得在路由转发层面做文章,前面我们有贴一个图片,图片中有许多默许的全局过滤器,其中有一个LoadBalancerClientFilter是担任挑选路由效劳的负载过滤器,内里会经由过程loadBalancer去挑选转发的效劳,然后通报到下面的路由NettyRoutingFilter过滤器去实行,那末我们就能够基于这个机制来完成。
Filter中往下一个Filter中通报数据有用下面的体式格局:
exchange.getAttributes().put(GATEWAY_REQUEST_URL_ATTR, requestUrl);
猎取方直接猎取:
URI requestUrl = exchange.getRequiredAttribute(GATEWAY_REQUEST_URL_ATTR);
假如我想转变路由的话,就能够如许做:
@Component public class DebugFilter implements GlobalFilter, Ordered { @Override public int getOrder() { return 10101; } @Override public Mono<Void> filter(ServerWebExchange exchange, GatewayFilterChain chain) { try { exchange.getAttributes().put(GATEWAY_REQUEST_URL_ATTR, new URI("http://192.168.31.245:8081/house/hello2")); } catch (URISyntaxException e) { e.printStackTrace(); } return chain.filter(exchange); } }
LoadBalancerClientFilter的order是10100,我们这边比它大1,如许就能在它实行完之厥后替代要路由的地点了。
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