摘要:本文主要介绍了什么是GatewayFilter和GlobalFilter，以及区别和联系。然后介绍如何在Spring Cloud Gateway中自定义使用GatewayFilter和GlobalFilter。
1. Spring Cloud gateway的Filter
Spring Cloud gateway中的Filter从接口实现上分为两种一种是GatewayFilter，另外一种是GlobalFilter。
1.1 GatewayFilter与GlobalFilter的区别
区别用英语可以总结如下: At a high level global filters are applied to all routes, while a gateway filter will be applied to an individual route(s) >在一个高的角度来看，Global filters会被应用到所有的路由上，而Gateway filter将应用到单个路由上或者一个分组的路由上。在下面的案例中将会进行说明。
1.2 本文代码地址
2. GatewayFilter和GlobalFilter
2.1 GatewayFilter
2.1.1 什么是GatewayFilter
Contract for interception-style, chained processing of Web requests that may be used to implement cross-cutting, application-agnostic requirements such as security, timeouts, and others. Specific to a Gateway Copied from WebFilter >GatewayFilter是从WebFilter中Copy过来的，相当于一个Filter过滤器，可以对访问的URL过滤横切处理，应用场景比如超时，安全等。
从Spring Cloud Gateway的源码中如下所示，可以看出GatewayFilter的使用场景:
/**
* Contract for interception-style, chained processing of Web requests that may
* be used to implement cross-cutting, application-agnostic requirements such
* as security, timeouts, and others. Specific to a Gateway
*
* Copied from WebFilter
*
* @author Rossen Stoyanchev
* @since 5.0
*/
public interface GatewayFilter extends ShortcutConfigurable {
String NAME_KEY = "name";
String VALUE_KEY = "value";
/**
* Process the Web request and (optionally) delegate to the next
* {@code WebFilter} through the given {@link GatewayFilterChain}.
* @param exchange the current server exchange
* @param chain provides a way to delegate to the next filter
* @return {@code Mono<Void>} to indicate when request processing is complete
*/
Mono<Void> filter(ServerWebExchange exchange, GatewayFilterChain chain);
}
2.1.2 自定义GatewayFilter(Custom GatewayFilter)
如org.xujin.sc.filter.CustomFilter代码所示，通过自定义GatewayFilter对路由转发的处理时长统计。
package org.xujin.sc.filter;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.springframework.cloud.gateway.filter.GatewayFilter;
import org.springframework.cloud.gateway.filter.GatewayFilterChain;
import org.springframework.core.Ordered;
import org.springframework.web.server.ServerWebExchange;
import reactor.core.publisher.Mono;
/**
* 统计某个或者某种路由的的处理时长
* @author xujin
*/
public class CustomFilter implements GatewayFilter, Ordered {
private static final Log log = LogFactory.getLog(GatewayFilter.class);
private static final String COUNT_Start_TIME = "countStartTime";
@Override
public Mono<Void> filter(ServerWebExchange exchange, GatewayFilterChain chain) {
exchange.getAttributes().put(COUNT_Start_TIME, System.currentTimeMillis());
return chain.filter(exchange).then(
Mono.fromRunnable(() -> {
Long startTime = exchange.getAttribute(COUNT_Start_TIME);
Long endTime=(System.currentTimeMillis() - startTime);
if (startTime != null) {
log.info(exchange.getRequest().getURI().getRawPath() + ": " + endTime + "ms");
}
})
);
}
@Override
public int getOrder() {
return Ordered.LOWEST_PRECEDENCE;
}
}
2.1.3 Gateway Filter与RouteLocator绑定使用
在org.xujin.sc.GatewayServerApplication中customerRouteLocator如下所示:
@SpringBootApplication
public class GatewayServerApplication {
@Bean
public RouteLocator customerRouteLocator(RouteLocatorBuilder builder) {
return builder.routes()
.route(r -> r.path("/test/prefix/**")
.filters(f -> f.stripPrefix(2)
.filter(new CustomFilter())
.addResponseHeader("X-Response-test", "test"))
.uri("lb://SC-CONSUMER")
.order(0)
.id("test_consumer_service")
)
.build();
}
public static void main(String[] args) {
SpringApplication.run(GatewayServerApplication.class, args);
}
}
-
r.path(“/test/prefix/**“)表示自定义了访问前缀，在真正的Gateway进行路由转发的时候，会用过f.stripPrefix(2)把前缀去掉。 >使用场景:可以把对外暴露的URL通过加前缀分组打标。
-
filter(new CustomFilter() >filter(new CustomFilter()，表示把自定义的Filter加到Filter链里面执行，注意一点是自定义GlobalFilter不需要加进去。
-
uri(“lb://SC-CONSUMER”) >uri(“lb://SC-CONSUMER”)表示Spring Cloud Gateway对spring.application.name等于sc-consumer源服务应用中的URL进行协议适配转发。
2.1.4 测试如下:
1.访问http://localhost:9000/SC-CONSUMER/hello/xujin 能正常访问。
DEBUG 31658 --- [ctor-http-nio-2] o.s.c.g.h.RoutePredicateHandlerMapping : Route matched: CompositeDiscoveryClient_SC-CONSUMER
2018-05-27 09:58:07.905 DEBUG 31658 --- [ctor-http-nio-2] o.s.c.g.h.RoutePredicateHandlerMapping : Mapping [Exchange: GET http://localhost:9000/SC-CONSUMER/hello/xujin] to Route{id='CompositeDiscoveryClient_SC-CONSUMER', uri=lb://SC-CONSUMER, order=0, predicate=org.springframework.cloud.gateway.handler.predicate.PathRoutePredicateFactory$$Lambda$337/1295338046@f2ff0c8, gatewayFilters=[OrderedGatewayFilter{delegate=org.springframework.cloud.gateway.filter.factory.RewritePathGatewayFilterFactory$$Lambda$717/1168359877@1f74a2b, order=1}]}
2018-05-27 09:58:07.905 DEBUG 31658 --- [ctor-http-nio-2] o.s.c.g.handler.FilteringWebHandler : Sorted gatewayFilterFactories: [OrderedGatewayFilter{delegate=GatewayFilterAdapter{delegate=org.springframework.cloud.gateway.filter.NettyWriteResponseFilter@f5bf288}, order=-1}, OrderedGatewayFilter{delegate=org.springframework.cloud.gateway.filter.factory.RewritePathGatewayFilterFactory$$Lambda$717/1168359877@1f74a2b, order=1}, OrderedGatewayFilter{delegate=GatewayFilterAdapter{delegate=org.springframework.cloud.gateway.filter.RouteToRequestUrlFilter@26c77f54}, order=10000}, OrderedGatewayFilter{delegate=GatewayFilterAdapter{delegate=org.springframework.cloud.gateway.filter.LoadBalancerClientFilter@4c38cd16}, order=10100}, OrderedGatewayFilter{delegate=GatewayFilterAdapter{delegate=org.springframework.cloud.gateway.filter.AdaptCachedBodyGlobalFilter@2c1d57bc}, order=2147483637}, OrderedGatewayFilter{delegate=GatewayFilterAdapter{delegate=org.springframework.cloud.gateway.filter.WebsocketRoutingFilter@6e9a0bea}, order=2147483646}, OrderedGatewayFilter{delegate=GatewayFilterAdapter{delegate=org.springframework.cloud.gateway.filter.NettyRoutingFilter@7ddcb0dc}, order=2147483647}, OrderedGatewayFilter{delegate=GatewayFilterAdapter{delegate=org.springframework.cloud.gateway.filter.ForwardRoutingFilter@3e856100}, order=2147483647}]
2.加上URL前缀/test/prefix/访问，测试URL为 http://localhost:9000/test/prefix/hello/testCustomFilter/xujin
2018-05-27 10:01:56.057 DEBUG 31658 --- [ctor-http-nio-2] o.s.c.g.h.RoutePredicateHandlerMapping : Mapping [Exchange: GET http://localhost:9000/test/prefix/hello/testCustomFilter/xujin] to Route{id='test_consumer_service', uri=lb://SC-CONSUMER, order=0, predicate=org.springframework.cloud.gateway.handler.predicate.PathRoutePredicateFactory$$Lambda$337/1295338046@6dbaa72e, gatewayFilters=[OrderedGatewayFilter{delegate=org.springframework.cloud.gateway.filter.factory.StripPrefixGatewayFilterFactory$$Lambda$340/1149217113@41fb2078, order=0}, org.xujin.sc.filter.CustomFilter@281885a3, OrderedGatewayFilter{delegate=org.springframework.cloud.gateway.filter.factory.AddResponseHeaderGatewayFilterFactory$$Lambda$342/1099925775@4705cae6, order=0}]}
2018-05-27 10:01:56.057 DEBUG 31658 --- [ctor-http-nio-2] o.s.c.g.handler.FilteringWebHandler : Sorted gatewayFilterFactories: [OrderedGatewayFilter{delegate=GatewayFilterAdapter{delegate=org.springframework.cloud.gateway.filter.NettyWriteResponseFilter@f5bf288}, order=-1}, OrderedGatewayFilter{delegate=org.springframework.cloud.gateway.filter.factory.StripPrefixGatewayFilterFactory$$Lambda$340/1149217113@41fb2078, order=0}, OrderedGatewayFilter{delegate=org.springframework.cloud.gateway.filter.factory.AddResponseHeaderGatewayFilterFactory$$Lambda$342/1099925775@4705cae6, order=0}, OrderedGatewayFilter{delegate=GatewayFilterAdapter{delegate=org.springframework.cloud.gateway.filter.RouteToRequestUrlFilter@26c77f54}, order=10000}, OrderedGatewayFilter{delegate=GatewayFilterAdapter{delegate=org.springframework.cloud.gateway.filter.LoadBalancerClientFilter@4c38cd16}, order=10100}, OrderedGatewayFilter{delegate=GatewayFilterAdapter{delegate=org.springframework.cloud.gateway.filter.AdaptCachedBodyGlobalFilter@2c1d57bc}, order=2147483637}, OrderedGatewayFilter{delegate=GatewayFilterAdapter{delegate=org.springframework.cloud.gateway.filter.WebsocketRoutingFilter@6e9a0bea}, order=2147483646}, OrderedGatewayFilter{delegate=GatewayFilterAdapter{delegate=org.springframework.cloud.gateway.filter.NettyRoutingFilter@7ddcb0dc}, order=2147483647}, OrderedGatewayFilter{delegate=GatewayFilterAdapter{delegate=org.springframework.cloud.gateway.filter.ForwardRoutingFilter@3e856100}, order=2147483647}, org.xujin.sc.filter.CustomFilter@281885a3]
2018-05-27 10:02:00.347 INFO 31658 --- [ctor-http-nio-8] o.s.cloud.gateway.filter.GatewayFilter : /hello/testCustomFilter/xujin: 859ms
2.2 GlobalFilter
2.2.1 什么是GlobalFilter
Spring Cloud gateway定义了GlobalFilter的接口让我们去自定义实现自己的的GlobalFilter。GlobalFilter是一个全局的Filter，作用于所有的路由。
public interface GlobalFilter {
/**
* Process the Web request and (optionally) delegate to the next
* {@code WebFilter} through the given {@link GatewayFilterChain}.
* @param exchange the current server exchange
* @param chain provides a way to delegate to the next filter
* @return {@code Mono<Void>} to indicate when request processing is complete
*/
Mono<Void> filter(ServerWebExchange exchange, GatewayFilterChain chain);
}
2.2.2 自定义全局过滤器(Custom GlobalFilter)
在这里简单定义AuthSignatureFilter实现GlobalFilter，使用场景就是Gateway对请求的URL校验权限，判断请求的URL是否是合法请求。通过从ServerWebExchange获取请求上下文中authToken对应的值，进行判null处理，其它的check逻辑可以自定定制。
package org.xujin.sc.filter;
import org.springframework.cloud.gateway.filter.GatewayFilterChain;
import org.springframework.cloud.gateway.filter.GlobalFilter;
import org.springframework.core.Ordered;
import org.springframework.http.HttpStatus;
import org.springframework.stereotype.Component;
import org.springframework.web.server.ServerWebExchange;
import reactor.core.publisher.Mono;
/**
* 调用鉴权
*/
@Component
public class AuthSignatureFilter implements GlobalFilter, Ordered {
@Override
public Mono<Void> filter(ServerWebExchange exchange, GatewayFilterChain chain) {
String token = exchange.getRequest().getQueryParams().getFirst("authToken");
if (token == null || token.isEmpty()) {
exchange.getResponse().setStatusCode(HttpStatus.UNAUTHORIZED);
return exchange.getResponse().setComplete();
}
return chain.filter(exchange);
}
@Override
public int getOrder() {
return -200;
}
}
@Bean
public AuthSignatureFilter authSignatureFilter(){
return new AuthSignatureFilter();
}
测试
1.访问http://localhost:9000/test/prefix/hello/testCustomFilter/xujin 如下所示由于authToken为空401返回.
2.访问http://localhost:9000/test/prefix/hello/testCustomFilter/xujin?authToken=asdasdsddasadsadsadsdadsewew32rg
