SpringCloudGateway笔记(2)-filter与自定义filter

我就是我 2022-01-30 16:43 262阅读 0赞

filter与自定义filter

过滤器可以在路由请求之前对请求进行处理，也可以在请求响应之后对响应进行处理

在请求路由之前可以做比如参数校验，鉴权，日志记录，协议转换，请求参数修改，路径修改等

在请求响应之后可以做比如记录响应消息，修改响应，修改响应头等

#### 最常见的功能就是鉴权，日志记录，限流和权重路由 ####

Filter分为Gateway Filter和Global Filter

Gateway Filter 是可以指定对某个路由进行过滤操作，自带的Gateway Filter如下

<table> 
 <thead> 
  <tr> 
   <th>AddRequestHeader</th> 
   <th>作用</th> 
  </tr> 
 </thead> 
 <tbody> 
  <tr> 
   <td>AddRequestHeader</td> 
   <td>添加请求header</td> 
  </tr> 
  <tr> 
   <td>AddRequestParameter</td> 
   <td>添加请求参数</td> 
  </tr> 
  <tr> 
   <td>AddResponseHeader</td> 
   <td>添加响应header</td> 
  </tr> 
  <tr> 
   <td>DedupeResponseHeader</td> 
   <td>响应头去重</td> 
  </tr> 
  <tr> 
   <td>Hystrix GatewayFilters</td> 
   <td>断路器的网关</td> 
  </tr> 
  <tr> 
   <td>PrefixPath</td> 
   <td>路径匹配</td> 
  </tr> 
  <tr> 
   <td>PreserveHostHeader</td> 
   <td>发送原始host</td> 
  </tr> 
  <tr> 
   <td>RequestRateLimiter</td> 
   <td>限流</td> 
  </tr> 
  <tr> 
   <td>RedirectTo</td> 
   <td>重定向</td> 
  </tr> 
  <tr> 
   <td>RemoveHopByHopHeadersFilter</td> 
   <td>移除响应header，默认有Connection，Keep-Alive，Proxy-Authenticate，Proxy-Authorization，TE，Trailer，Transfer-Encoding，Upgrade</td> 
  </tr> 
  <tr> 
   <td>RemoveRequestHeader</td> 
   <td>移除请求header</td> 
  </tr> 
  <tr> 
   <td>RemoveResponseHeader</td> 
   <td>移除响应header</td> 
  </tr> 
  <tr> 
   <td>RewritePath</td> 
   <td>路径重写</td> 
  </tr> 
  <tr> 
   <td>RewriteResponseHeader</td> 
   <td>重写响应header</td> 
  </tr> 
  <tr> 
   <td>SaveSession</td> 
   <td>保存session</td> 
  </tr> 
  <tr> 
   <td>SetPath</td> 
   <td>模板匹配路径修改</td> 
  </tr> 
  <tr> 
   <td>SetResponseHeader</td> 
   <td>设置响应header，会覆盖所有原有的header</td> 
  </tr> 
  <tr> 
   <td>SetStatus</td> 
   <td>设置httpStatus响应码</td> 
  </tr> 
  <tr> 
   <td>StripPrefix</td> 
   <td>去掉前缀</td> 
  </tr> 
  <tr> 
   <td>Retry</td> 
   <td>重试次数</td> 
  </tr> 
  <tr> 
   <td>RequestSize</td> 
   <td>请求大小限制</td> 
  </tr> 
  <tr> 
   <td>ModifyRequestBody</td> 
   <td>修改请求体</td> 
  </tr> 
  <tr> 
   <td>ModifyResponseBody</td> 
   <td>修改响应体</td> 
  </tr> 
 </tbody> 
</table>

#### 写个demo测试一下 ####

routes:
            - id: spring-cloud-client-demo
              url: lb://spring-cloud-client-demo
              predicates:
                - Path=/client/**
              filters:
                - AddRequestHeader=X-Request-Foo, Bar
                - StripPrefix=1

使用Postman发送请求

GET [http://localhost:10001/client/demo/get?param=aaa][http_localhost_10001_client_demo_get_param_aaa]

可以看到请求被转发到spring-cloud-client-demo的/demo/get?param=aaa

同时查看请求头打印，可以看到添加的请求头

2019-05-18 11:03:17.501  INFO 13612 --- [nio-8801-exec-1] c.m.d.client.controller.DemoController   : header: accept, */*
    2019-05-18 11:03:17.501  INFO 13612 --- [nio-8801-exec-1] c.m.d.client.controller.DemoController   : header: postman-token, d90bc432-9861-4170-8c21-a66be561446f
    2019-05-18 11:03:17.501  INFO 13612 --- [nio-8801-exec-1] c.m.d.client.controller.DemoController   : header: accept-encoding, gzip, deflate
    2019-05-18 11:03:17.501  INFO 13612 --- [nio-8801-exec-1] c.m.d.client.controller.DemoController   : header: cache-control, no-cache
    2019-05-18 11:03:17.501  INFO 13612 --- [nio-8801-exec-1] c.m.d.client.controller.DemoController   : header: x-request-foo, Bar
    2019-05-18 11:03:17.501  INFO 13612 --- [nio-8801-exec-1] c.m.d.client.controller.DemoController   : header: user-agent, PostmanRuntime/7.4.0
    2019-05-18 11:03:17.501  INFO 13612 --- [nio-8801-exec-1] c.m.d.client.controller.DemoController   : header: forwarded, proto=http;host="localhost:10001";for="0:0:0:0:0:0:0:1:62526"
    2019-05-18 11:03:17.501  INFO 13612 --- [nio-8801-exec-1] c.m.d.client.controller.DemoController   : header: x-forwarded-for, 0:0:0:0:0:0:0:1
    2019-05-18 11:03:17.501  INFO 13612 --- [nio-8801-exec-1] c.m.d.client.controller.DemoController   : header: x-forwarded-proto, http
    2019-05-18 11:03:17.502  INFO 13612 --- [nio-8801-exec-1] c.m.d.client.controller.DemoController   : header: x-forwarded-prefix, /client
    2019-05-18 11:03:17.502  INFO 13612 --- [nio-8801-exec-1] c.m.d.client.controller.DemoController   : header: x-forwarded-port, 10001
    2019-05-18 11:03:17.502  INFO 13612 --- [nio-8801-exec-1] c.m.d.client.controller.DemoController   : header: x-forwarded-host, localhost:10001
    2019-05-18 11:03:17.502  INFO 13612 --- [nio-8801-exec-1] c.m.d.client.controller.DemoController   : header: host, 192.168.56.1:8801
    2019-05-18 11:03:17.502  INFO 13612 --- [nio-8801-exec-1] c.m.d.client.controller.DemoController   : header: content-length, 0

Global Filter是全局的过滤器，配置之后对所有路由都有效

<table> 
 <thead> 
  <tr> 
   <th>过滤器</th> 
   <th>说明</th> 
  </tr> 
 </thead> 
 <tbody> 
  <tr> 
   <td>LoadBalancerClientFilter</td> 
   <td>负载均衡过滤器</td> 
  </tr> 
  <tr> 
   <td>Netty Routing Filter</td> 
   <td>默认使用netty的底层</td> 
  </tr> 
  <tr> 
   <td>RouteToRequestUrlFilter</td> 
   <td>新的请求路由</td> 
  </tr> 
  <tr> 
   <td>Websocket Routing Filter</td> 
   <td>websocket路由</td> 
  </tr> 
  <tr> 
   <td>Gateway Metrics Filter</td> 
   <td>路由监控，配合spring-boot-starter-actuator</td> 
  </tr> 
 </tbody> 
</table>

微服务使用·负载均衡用

uri: lb://spring-cloud-client-demo

websocket

uri: lb:ws://spring-cloud-client-demo

直接路由

uri:http:/xxxx.com

#### 自定义全局过滤器 ####

@Slf4j
    @Component
    public class MyFilter implements GlobalFilter, Ordered {
        @Override
        public Mono<Void> filter(ServerWebExchange exchange, GatewayFilterChain chain) {
            log.info("this is a pre filter");
            return chain.filter(exchange).then(Mono.fromRunnable(() -> {
                log.info("this is a post filter");
            }));
        }
    
        @Override
        public int getOrder() {
            return -1;
        }
    }

注：

1.  这里的order不能使用@order 的注解
2.  在fitler里面的是pre类型，会在路由前执行，在then里面的是post类型会在路由后执行
3.  order 的数值越小pre越先执行，post越后执行

再写一个filter测试一下

@Slf4j
    @Component
    public class MyFilter2 implements GlobalFilter, Ordered {
        @Override
        public Mono<Void> filter(ServerWebExchange exchange, GatewayFilterChain chain) {
            log.info("this is a pre filter2");
            return chain.filter(exchange).then(Mono.fromRunnable(() -> {
                log.info("this is a post filter2");
            }));
        }
    
        @Override
        public int getOrder() {
            return -2;
        }
    }

执行一个请求查看日志信息

2019-05-18 12:17:22.874  INFO 12996 --- [ctor-http-nio-3] com.mt.demo.gateway.filter.MyFilter2     : this is a pre filter2
    2019-05-18 12:17:22.874  INFO 12996 --- [ctor-http-nio-3] com.mt.demo.gateway.filter.MyFilter      : this is a pre filter
    2019-05-18 12:17:23.191  INFO 12996 --- [ctor-http-nio-3] com.mt.demo.gateway.filter.MyFilter      : this is a post filter
    2019-05-18 12:17:23.191  INFO 12996 --- [ctor-http-nio-3] com.mt.demo.gateway.filter.MyFilter2     : this is a post filter2

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![在这里插入图片描述][70]

[http_localhost_10001_client_demo_get_param_aaa]: http://localhost:10001/client/demo/get?param=aaa
[70]: /images/20220130/85c9aabcea2546b799ab359314b6efb3.png