SpringCloud 2.x学习笔记：15、Spring Cloud Gateway之Filter过滤器（Greenwich版本）

左手的ㄟ右手 2022-01-12 11:13 188阅读 0赞

### 1、AddRequestHeader过滤器 ###

server:
      port: 7013
    ---
    spring:
      cloud:
        gateway:
          routes:
          - id: add_request_header_route
            uri: http://httpbin.org
            filters:
            - AddRequestHeader=X-Request-Flag, HelloWorld
            predicates:
            - After=2019-06-20T00:00:00+08:00[Asia/Shanghai]
      profiles: add_request_header_route

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2NoZW5neXVxaWFuZw_size_16_color_FFFFFF_t_70]  
[http://localhost:7013/get][http_localhost_7013_get]  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2NoZW5neXVxaWFuZw_size_16_color_FFFFFF_t_70 1]  
AddRequestHeaderGatewayFilterFactory的源码

package org.springframework.cloud.gateway.filter.factory;
    
    import org.springframework.cloud.gateway.filter.GatewayFilter;
    import org.springframework.http.server.reactive.ServerHttpRequest;
    
    /**
     * @author Spencer Gibb
     */
    public class AddRequestHeaderGatewayFilterFactory
    		extends AbstractNameValueGatewayFilterFactory {
    
    	@Override
    	public GatewayFilter apply(NameValueConfig config) {
    		return (exchange, chain) -> {
    			ServerHttpRequest request = exchange.getRequest().mutate()
    					.header(config.getName(), config.getValue()).build();
    
    			return chain.filter(exchange.mutate().request(request).build());
    		};
    	}
    
    }

从代码可知道，由当前的ServerHttpRequest创建新 ServerHttpRequest ，并在新的ServerHttpRequest加一个请求头，然后创建新的 ServerWebExchange ，提交过滤器链继续过滤。

### 2、AddResponseHeader过滤器 ###

---
    spring:
      cloud:
        gateway:
          routes:
          - id: add_response_header_route
            uri: http://httpbin.org:80/get
            filters:
            - AddResponseHeader=X-Response-Flag, Hadron
            predicates:
            - After=2019-06-20T00:00:00+08:00[Asia/Shanghai]
      profiles: add_response_header_route

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2NoZW5neXVxaWFuZw_size_16_color_FFFFFF_t_70 2]

C:\Windows\System32>curl -I localhost:7013
    HTTP/1.1 200 OK
    X-Response-Flag: Hadron
    Access-Control-Allow-Credentials: true
    Access-Control-Allow-Origin: *
    Content-Type: text/html; charset=utf-8
    Date: Fri, 21 Jun 2019 09:01:14 GMT
    Referrer-Policy: no-referrer-when-downgrade
    Server: nginx
    X-Content-Type-Options: nosniff
    X-Frame-Options: DENY
    X-XSS-Protection: 1; mode=block
    Content-Length: 0

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2NoZW5neXVxaWFuZw_size_16_color_FFFFFF_t_70 3]

### 3、RewritePath 过滤器 ###

---
    spring:
      cloud:
        gateway:
          routes:
          - id: rewritepath_route
            uri: https://blog.csdn.net/chengyuqiang
            predicates:
            - Path=/foo/**
            filters:
            - RewritePath=/foo/(?<segment>.*), /$\{segment}
      profiles: rewritepath_route

RewritePath 过滤器将/foo/(?.\*)重写为\{segment\}，然后转发到https://blog.csdn.net。  
比如请求`http://localhost:7013/foo/chengyuqiang`，RewritePath 过滤器将`/foo/chengyuqiang`重写为`chengyuqiang`，然后转发到`https://blog.csdn.net`，这样路径就是`https://blog.csdn.net/chengyuqiang`  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2NoZW5neXVxaWFuZw_size_16_color_FFFFFF_t_70 4]  
[http://localhost:7013/foo/chengyuqiang][http_localhost_7013_foo_chengyuqiang]  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2NoZW5neXVxaWFuZw_size_16_color_FFFFFF_t_70 5]

### 4、PrefixPath过滤器 ###

---
    spring:
      cloud:
        gateway:
          routes:
          - id: prefixpath_route
            uri: https://blog.csdn.net
            predicates:
            - Path=/article/**
            filters:
            - PrefixPath=/chengyuqiang
      profiles: prefixpath_route

比如：请求/hello，最后转发到目标服务的路径变为/chengyuqiang/hello

[http://localhost:7013/article/details/85019277][http_localhost_7013_article_details_85019277]  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2NoZW5neXVxaWFuZw_size_16_color_FFFFFF_t_70 6]  
注意，这个页面会再次跳转到https://www.csdn.net/首页

### 5、StripPrefix过滤器 ###

---
    spring:
      cloud:
        gateway:
          routes:
          - id: stripprefix_route
            uri: https://httpbin.org
            predicates:
            - Path=/my/**
            filters:
            - StripPrefix=2
      profiles: stripprefix_route

比如，请求/my/bar/get，( StripPrefix=2)去除掉前面两个前缀之后，最后转发到目标服务的路径为/get

[http://localhost:7013/my/bar/get][http_localhost_7013_my_bar_get]  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2NoZW5neXVxaWFuZw_size_16_color_FFFFFF_t_70 7]

### 6、自定义过滤器 ###

下面，我们自定义一个filter用来统计每次请求的时长。

package com.cntaiping.tpa.gatewayfilter.filter;
    
    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;
    
    public class MyFilter implements GatewayFilter, Ordered {
    
        private static final String REQUEST_TIME_BEGIN = "requestTimeBegin";
    
        @Override
        public Mono<Void> filter(ServerWebExchange exchange, GatewayFilterChain chain) {
            //记录请求开始时间,并保存在ServerWebExchange中
            exchange.getAttributes().put(REQUEST_TIME_BEGIN, System.currentTimeMillis());
    
            return chain.filter(exchange)//“pre”类型的过滤器
                    .then(Mono.fromRunnable(// run()方法中相当于"post"过滤器
                    () ->{
                        Long startTime = exchange.getAttribute(REQUEST_TIME_BEGIN);
                        if (startTime != null) {
                            System.out.println(exchange.getRequest().getURI() + " 耗时" + (System.currentTimeMillis() - startTime));
                        }
                    }
            ));
        }
    
        @Override
        public int getOrder() {
            //设定优先级别的，值越大则优先级越低
            return 0;
        }
    }

将自定义filter注册到路由中

package com.cntaiping.tpa.gatewayfilter;
    
    import com.cntaiping.tpa.gatewayfilter.filter.MyFilter;
    import org.springframework.boot.SpringApplication;
    import org.springframework.boot.autoconfigure.SpringBootApplication;
    import org.springframework.cloud.gateway.filter.factory.AddRequestHeaderGatewayFilterFactory;
    import org.springframework.cloud.gateway.route.RouteLocator;
    import org.springframework.cloud.gateway.route.builder.RouteLocatorBuilder;
    import org.springframework.context.annotation.Bean;
    
    @SpringBootApplication
    public class GatewayFilterApplication {
    
        public static void main(String[] args) {
            SpringApplication.run(GatewayFilterApplication.class, args);
        }
    
        @Bean
        public RouteLocator customerRouteLocator(RouteLocatorBuilder builder) {
            return builder.routes()
                    .route(r -> r.path("/my/**")
                            .filters(f -> f.filter(new MyFilter())
                                    .addResponseHeader("X-Response-Default-Flag", "Default-Flag"))
                            .uri("http://httpbin.org:80/get")
                            .order(0)
                            .id("my_filter_router")
                    )
                    .build();
        }
    
    }

重启服务

curl localhost:7013/my/123

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### 6、自定义过滤器工厂 ###

下面演示自定义过滤器工厂类，这样就可以非常方便的在配置文件中配置过滤器。

springboot约定过滤器工厂的前缀为配置的name，所以自定义的过滤器工厂类的后缀是GatewayFilterFactory

package com.cntaiping.tpa.gatewayfilter.filter;
    
    import org.slf4j.Logger;
    import org.slf4j.LoggerFactory;
    import org.springframework.cloud.gateway.filter.GatewayFilter;
    import org.springframework.cloud.gateway.filter.factory.AbstractGatewayFilterFactory;
    import reactor.core.publisher.Mono;
    
    import java.util.*;
    
    public class MyGatewayFilterFactory extends AbstractGatewayFilterFactory<MyGatewayFilterFactory.Config> {
        private Logger logger = LoggerFactory.getLogger(getClass());
        /**
         * 定义可以再yaml中声明的属性变量
         */
        private static final String TYPE = "type";
        private static final String OP = "op";
    
        public MyGatewayFilterFactory(){
            // 这里需要将自定义的config传过去，否则会报告ClassCastException
            super(Config.class);
        }
    
        @Override
        public List<String> shortcutFieldOrder() {
            return Arrays.asList(TYPE, OP);
        }
    
        @Override
        public GatewayFilter apply(Config config) {
            return ((exchange, chain) -> {
                boolean root = "root".equals(config.getOp());
                if (root){
                    logger.info("GatewayFilter root");
                }
                else {
                    logger.info("GatewayFilter customer");
                }
                // 在then方法里的，相当于aop中的后置通知
                return chain.filter(exchange).then(Mono.fromRunnable(()->{
                    // do something
                    logger.info(System.currentTimeMillis()+"");
                }));
            });
        }
    
        /**
         * 自定义的config类，用来设置传入的参数
         */
        public static class Config {
    
            /**
             * 过滤类型
             */
            private String type;
    
            /**
             * 操作
             */
            private String op;
    
            public String getType() {
                return type;
            }
    
            public void setType(String type) {
                this.type = type;
            }
    
            public String getOp() {
                return op;
            }
    
            public void setOp(String op) {
                this.op = op;
            }
        }
    }

package com.cntaiping.tpa.gatewayfilter;
    
    import com.cntaiping.tpa.gatewayfilter.filter.MyFilter;
    import com.cntaiping.tpa.gatewayfilter.filter.MyGatewayFilterFactory;
    import org.springframework.boot.SpringApplication;
    import org.springframework.boot.autoconfigure.SpringBootApplication;
    import org.springframework.cloud.gateway.route.RouteLocator;
    import org.springframework.cloud.gateway.route.builder.RouteLocatorBuilder;
    import org.springframework.context.annotation.Bean;
    
    @SpringBootApplication
    public class GatewayFilterApplication {
    
        public static void main(String[] args) {
            SpringApplication.run(GatewayFilterApplication.class, args);
        }
    
    /*    @Bean
        public RouteLocator customerRouteLocator(RouteLocatorBuilder builder) {
            return builder.routes()
                    .route(r -> r.path("/my/**")
                            .filters(f -> f.filter(new MyFilter())
                                    .addResponseHeader("X-Response-Default-Flag", "Default-Flag"))
                            .uri("http://httpbin.org:80/get")
                            .order(0)
                            .id("my_filter_router")
                    )
                    .build();
        }*/
    
        @Bean
        public MyGatewayFilterFactory exampleGatewayFilterFactory(){
            return new MyGatewayFilterFactory();
        }
    
    }

---
    spring:
      cloud:
        gateway:
          routes:
          - id: myfilter_route
            uri: http://httpbin.org:80/get
            filters:
            - name: My
              args:
                op: root
                type: he
            predicates:
            - After=2017-01-20T17:42:47.789-07:00[America/Denver]
      profiles: myfilter_route

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2NoZW5neXVxaWFuZw_size_16_color_FFFFFF_t_70 9]

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2NoZW5neXVxaWFuZw_size_16_color_FFFFFF_t_70 10]

### 7、global过滤器 ###

package com.cntaiping.tpa.gatewayfilter.filter;
    
    import org.slf4j.Logger;
    import org.slf4j.LoggerFactory;
    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.web.server.ServerWebExchange;
    import reactor.core.publisher.Mono;
    
    public class TokenFilter implements GlobalFilter, Ordered {
    
        private Logger logger = LoggerFactory.getLogger(getClass());
    
        /**
         * 该全局过滤器会校验请求中是否包含token请求参数
         * 如何不包含，则不转发路由；否则执行正常的逻辑。
         * @param exchange
         * @param chain
         * @return
         */
        @Override
        public Mono<Void> filter(ServerWebExchange exchange, GatewayFilterChain chain) {
            String token = exchange.getRequest().getQueryParams().getFirst("token");
            if (token == null || token.isEmpty()) {
                logger.info( "token is empty..." );
                exchange.getResponse().setStatusCode(HttpStatus.UNAUTHORIZED);
                return exchange.getResponse().setComplete();
            }
            return chain.filter(exchange);
        }
    
        @Override
        public int getOrder() {
            return -100;
        }
    }

package com.cntaiping.tpa.gatewayfilter;
    
    import com.cntaiping.tpa.gatewayfilter.filter.MyFilter;
    import com.cntaiping.tpa.gatewayfilter.filter.MyGatewayFilterFactory;
    import com.cntaiping.tpa.gatewayfilter.filter.TokenFilter;
    import org.springframework.boot.SpringApplication;
    import org.springframework.boot.autoconfigure.SpringBootApplication;
    import org.springframework.cloud.gateway.route.RouteLocator;
    import org.springframework.cloud.gateway.route.builder.RouteLocatorBuilder;
    import org.springframework.context.annotation.Bean;
    
    @SpringBootApplication
    public class GatewayFilterApplication {
    
        public static void main(String[] args) {
            SpringApplication.run(GatewayFilterApplication.class, args);
        }
    
    /*    @Bean
        public RouteLocator customerRouteLocator(RouteLocatorBuilder builder) {
            return builder.routes()
                    .route(r -> r.path("/my/**")
                            .filters(f -> f.filter(new MyFilter())
                                    .addResponseHeader("X-Response-Default-Flag", "Default-Flag"))
                            .uri("http://httpbin.org:80/get")
                            .order(0)
                            .id("my_filter_router")
                    )
                    .build();
        }*/
    
        @Bean
        public MyGatewayFilterFactory exampleGatewayFilterFactory(){
            return new MyGatewayFilterFactory();
        }
    
        @Bean
        public TokenFilter tokenFilter(){
            return new TokenFilter();
        }
    }

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2NoZW5neXVxaWFuZw_size_16_color_FFFFFF_t_70 11]  
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[http_localhost_7013_get]: http://localhost:7013/get
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2NoZW5neXVxaWFuZw_size_16_color_FFFFFF_t_70 1]: /images/20220109/41b3cc2418124d30a1c9b9a7f8cf2fd8.png
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[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2NoZW5neXVxaWFuZw_size_16_color_FFFFFF_t_70 3]: /images/20220109/2c1c8abdbcc24b6aaa0fdfc01a870000.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2NoZW5neXVxaWFuZw_size_16_color_FFFFFF_t_70 4]: /images/20220109/401c8c7a0b06488994a77f4df4aecd35.png
[http_localhost_7013_foo_chengyuqiang]: http://localhost:7013/foo/chengyuqiang
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2NoZW5neXVxaWFuZw_size_16_color_FFFFFF_t_70 5]: /images/20220109/440cfc97c99247f69c821aa567b565b6.png
[http_localhost_7013_article_details_85019277]: http://localhost:7013/article/details/85019277
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2NoZW5neXVxaWFuZw_size_16_color_FFFFFF_t_70 6]: /images/20220109/983c3ee5e3294224bfbf1c6cd44db9fa.png
[http_localhost_7013_my_bar_get]: http://localhost:7013/my/bar/get
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