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Spring Cloud Gateway-过滤器工厂详解(GatewayFilter Factories)

目录

TIPS

本文基于 Spring Cloud Greenwich SR2 ,理论支持 Spring Cloud Greenwich SR1 ,其中的新特性标注出来了。

这一节来探讨Spring Cloud Gateway内置的Filter工厂。包括:

1 AddRequestHeader GatewayFilter Factory
2 AddRequestParameter GatewayFilter Factory
3 AddResponseHeader GatewayFilter Factory
4 DedupeResponseHeader GatewayFilter Factory
5 Hystrix GatewayFilter Factory
6 FallbackHeaders GatewayFilter Factory
7 PrefixPath GatewayFilter Factory
8 PreserveHostHeader GatewayFilter Factory
9 RequestRateLimiter GatewayFilter Factory
10 RedirectTo GatewayFilter Factory
11 RemoveHopByHopHeadersFilter GatewayFilter Factory
12 RemoveRequestHeader GatewayFilter Factory
13 RemoveResponseHeader GatewayFilter Factory
14 RewritePath GatewayFilter Factory
15 RewriteResponseHeader GatewayFilter Factory
16 SaveSession GatewayFilter Factory
17 SecureHeaders GatewayFilter Factory
18 SetPath GatewayFilter Factory
19 SetResponseHeader GatewayFilter Factory
20 SetStatus GatewayFilter Factory
21 StripPrefix GatewayFilter Factory
22 Retry GatewayFilter Factory
23 RequestSize GatewayFilter Factory
24 Modify Request Body GatewayFilter Factory
25 Modify Response Body GatewayFilter Factory
26 Default Filters

技巧

  • 断点打在 org.springframework.cloud.gateway.filter.NettyRoutingFilter#filter ,就可以调试Gateway转发的具体细节了。

  • 添加如下配置,可观察到一些请求细节:

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    logging:
    level:
    org.springframework.cloud.gateway: trace
    org.springframework.http.server.reactive: debug
    org.springframework.web.reactive: debug
    reactor.ipc.netty: debug

1 AddRequestHeader GatewayFilter Factory

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spring:
cloud:
gateway:
routes:
- id: add_request_header_route
uri: https://example.org
filters:
- AddRequestHeader=X-Request-Foo, Bar

为原始请求添加名为 X-Request-Foo ,值为 Bar 的请求头。

2 AddRequestParameter GatewayFilter Factory

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spring:
cloud:
gateway:
routes:
- id: add_request_parameter_route
uri: https://example.org
filters:
- AddRequestParameter=foo, bar

为原始请求添加请求参数 foo=bar

3 AddResponseHeader GatewayFilter Factory

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spring:
cloud:
gateway:
routes:
- id: add_response_header_route
uri: https://example.org
filters:
- AddResponseHeader=X-Response-Foo, Bar

添加名为 X-Request-Foo ,值为 Bar 的响应头。

4 DedupeResponseHeader GatewayFilter Factory

TIPS

Spring Cloud Greenwich SR2提供的新特性,低于这个版本无法使用。

强烈建议阅读一下类org.springframework.cloud.gateway.filter.factory.DedupeResponseHeaderGatewayFilterFactory上的注释,比官方文档写得还好。

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spring:
cloud:
gateway:
routes:
- id: dedupe_response_header_route
uri: https://example.org
filters:
- DedupeResponseHeader=Access-Control-Allow-Credentials Access-Control-Allow-Origin, RETAIN_FIRST

剔除重复的响应头。

举个例子:

我们在Gateway以及微服务上都设置了CORS(解决跨域)header,如果不做任何配置,请求 -> 网关 -> 微服务,获得的响应就是这样的:

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Access-Control-Allow-Credentials: true, true
Access-Control-Allow-Origin: https://musk.mars, https://musk.mars

也就是Header重复了。要想把这两个Header去重,只需设置成如下即可。

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filters:
- DedupeResponseHeader=Access-Control-Allow-Credentials Access-Control-Allow-Origin

也就是说,想要去重的Header如果有多个,用空格分隔即可;

去重策略:

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RETAIN_FIRST: 默认值,保留第一个值
RETAIN_LAST: 保留最后一个值
RETAIN_UNIQUE: 保留所有唯一值,以它们第一次出现的顺序保留

5 Hystrix GatewayFilter Factory

TIPS

Hystrix是Spring Cloud第一代中的容错组件,不过已经进入维护模式(相关文章:Spring Cloud Netflix项目进入维护模式之我见 ),未来,Hystrix会被Spring Cloud移除掉,取而代之的是Alibaba Sentinel/Resilience4J

所以本文不做详细探讨了,但Gateway整合Hystrix其实包含了很多姿势。请感兴趣的同学自行前往官方文档了解详情:https://cloud.spring.io/spring-cloud-static/Greenwich.SR2/single/spring-cloud.html#hystrix

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spring:
cloud:
gateway:
routes:
- id: hystrix_route
uri: https://example.org
filters:
- Hystrix=myCommandName

6 FallbackHeaders GatewayFilter Factory

TIPS

也是对Hystrix的支持,不做详细探讨了,请感兴趣的同学自行前往官方文档了解详情:https://cloud.spring.io/spring-cloud-static/Greenwich.SR2/single/spring-cloud.html#fallback-headers

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spring:
cloud:
gateway:
routes:
- id: ingredients
uri: lb://ingredients
predicates:
- Path=/ingredients/**
filters:
- name: Hystrix
args:
name: fetchIngredients
fallbackUri: forward:/fallback
- id: ingredients-fallback
uri: http://localhost:9994
predicates:
- Path=/fallback
filters:
- name: FallbackHeaders
args:
executionExceptionTypeHeaderName: Test-Header

7 PrefixPath GatewayFilter Factory

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spring:
cloud:
gateway:
routes:
- id: prefixpath_route
uri: https://example.org
filters:
- PrefixPath=/mypath

为匹配的路由添加前缀。例如:访问${GATEWAY_URL}/hello 会转发到https://example.org/mypath/hello

8 PreserveHostHeader GatewayFilter Factory

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spring:
cloud:
gateway:
routes:
- id: preserve_host_route
uri: https://example.org
filters:
- PreserveHostHeader

如果不设置,那么名为 Host 的Header由Http Client控制;如果设置了,那么会设置一个请求属性(preserveHostHeader=true),路由过滤器会检查从而去判断是否要发送原始的、名为Host的Header。

9 RequestRateLimiter GatewayFilter Factory

TIPS

在视频Spring Cloud Gateway一章,限流一节会详细讲解。也可阅读官方文档 https://cloud.spring.io/spring-cloud-static/Greenwich.SR2/single/spring-cloud.html#_requestratelimiter_gatewayfilter_factory

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spring:
cloud:
gateway:
routes:
- id: requestratelimiter_route
uri: https://example.org
filters:
- name: RequestRateLimiter
args:
redis-rate-limiter.replenishRate: 10
redis-rate-limiter.burstCapacity: 20

10 RedirectTo GatewayFilter Factory

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spring:
cloud:
gateway:
routes:
- id: prefixpath_route
uri: https://example.org
filters:
# 配置成HTTP状态码, URL的形式
- RedirectTo=302,
  • HTTP状态码应该是HTTP状态码300序列,例如301
  • URL必须是合法的URL,并且该值会作为名为 Location 的Header。

上面配置表达的意思是: ${GATEWAY_URL}/hello 会重定向到 https://ecme.org/hello ,并且携带一个 Location: 的Header。

11 RemoveHopByHopHeadersFilter GatewayFilter Factory

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spring.cloud.gateway.filter.remove-hop-by-hop.headers: Connection,Keep-Alive

移除转发请求的Header,多个用 , 分隔。默认情况下,移除如下Header。这些Header是由 IETF 组织规定的。

  • Connection
  • Keep-Alive
  • Proxy-Authenticate
  • Proxy-Authorization
  • TE
  • Trailer
  • Transfer-Encoding
  • Upgrade

12 RemoveRequestHeader GatewayFilter Factory

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spring:
cloud:
gateway:
routes:
- id: removerequestheader_route
uri: https://example.org
filters:
- RemoveRequestHeader=X-Request-Foo

为原始请求删除名为 X-Request-Foo 的请求头。

13 RemoveResponseHeader GatewayFilter Factory

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spring:
cloud:
gateway:
routes:
- id: removeresponseheader_route
uri: https://example.org
filters:
- RemoveResponseHeader=X-Response-Foo

删除名为 X-Request-Foo 的响应头。

14 RewritePath GatewayFilter Factory

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spring:
cloud:
gateway:
routes:
- id: rewritepath_route
uri: https://example.org
predicates:
- Path=/foo/**
filters:
# 配置成原始路径正则, 重写后的路径的正则
- RewritePath=/foo/(?<segment>.*), /$\{segment}

重写请求路径。如上配置,访问 /foo/bar 会将路径改为/bar 再转发,也就是会转发到 https://example.org/bar 。需要注意的是,由于YAML语法,需用$\ 替换 $

15 RewriteResponseHeader GatewayFilter Factory

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spring:
cloud:
gateway:
routes:
- id: rewriteresponseheader_route
uri: https://example.org
filters:
- RewriteResponseHeader=X-Response-Foo, password=[^&]+, password=***

如果名为 X-Response-Foo 的响应头的内容是/42?user=ford&password=omg!what&flag=true,则会被修改为/42?user=ford&password=***&flag=true

16 SaveSession GatewayFilter Factory

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spring:
cloud:
gateway:
routes:
- id: save_session
uri: https://example.org
predicates:
- Path=/foo/**
filters:
- SaveSession

在转发到后端微服务请求之前,强制执行 WebSession::save 操作。用在那种像 Spring Session 延迟数据存储(笔者注:数据不是立刻持久化)的,并希望在请求转发前确保session状态保存情况。

如果你将Spring SecutirySpring Session集成使用,并想确保安全信息都传到下游机器,你就需要配置这个filter。

17 SecureHeaders GatewayFilter Factory

添加一系列起安全作用的响应头。Spring Cloud Gateway参考了这篇博客的建议:https://blog.appcanary.com/2017/http-security-headers.html

默认会添加如下Header(包括值):

  • X-Xss-Protection:1; mode=block
  • Strict-Transport-Security:max-age=631138519
  • X-Frame-Options:DENY
  • X-Content-Type-Options:nosniff
  • Referrer-Policy:no-referrer
  • Content-Security-Policy:default-src 'self' https:; font-src 'self' https: data:; img-src 'self' https: data:; object-src 'none'; script-src https:; style-src 'self' https: 'unsafe-inline'
  • X-Download-Options:noopen
  • X-Permitted-Cross-Domain-Policies:none

如果你想修改这些Header的值,可使用如下配置:

前缀:spring.cloud.gateway.filter.secure-headers

上面的header对应的后缀:

  • xss-protection-header
  • strict-transport-security
  • frame-options
  • content-type-options
  • referrer-policy
  • content-security-policy
  • download-options
  • permitted-cross-domain-policies

例如:spring.cloud.gateway.filter.secure-headers.xss-protection-header: 你想要的值

如果想禁用某些Header,可使用如下配置:spring.cloud.gateway.filter.secure-headers.disable ,多个用 , 分隔。例如:spring.cloud.gateway.filter.secure-headers.disable=frame-options,download-options

18 SetPath GatewayFilter Factory

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spring:
cloud:
gateway:
routes:
- id: setpath_route
uri: https://example.org
predicates:
- Path=/foo/{segment}
filters:
- SetPath=/{segment}

采用路径template参数,通过请求路径的片段的模板化,来达到操作修改路径的母的,运行多个路径片段模板化。

如上配置,访问${GATEWAY_PATH}/foo/bar ,则对于后端微服务的路径会修改为 /bar

19 SetResponseHeader GatewayFilter Factory

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spring:
cloud:
gateway:
routes:
- id: setresponseheader_route
uri: http://example.org
filters:
- SetResponseHeader=X-Response-Foo, Bar

如果后端服务响应带有名为 X-Response-Foo 的响应头,则将值改为替换成 Bar

20 SetStatus GatewayFilter Factory

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spring:
cloud:
gateway:
routes:
- id: setstatusstring_route
uri: http://example.org
filters:
- SetStatus=BAD_REQUEST
- id: setstatusint_route
uri: http://example.org
filters:
- SetStatus=401

修改响应的状态码,值可以是数字,也可以是字符串。但一定要是Spring HttpStatus 枚举类中的值。如上配置,两种方式都可以返回HTTP状态码401。

21 StripPrefix GatewayFilter Factory

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spring:
cloud:
gateway:
routes:
- id: nameRoot
uri: http://nameservice
predicates:
- Path=/name/**
filters:
- StripPrefix=2

数字表示要截断的路径的数量。如上配置,如果请求的路径为 /name/bar/foo ,则路径会修改为/foo ,也就是会截断2个路径。

22 Retry GatewayFilter Factory

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spring:
cloud:
gateway:
routes:
- id: retry_test
uri: http://localhost:8080/flakey
predicates:
- Host=*.retry.com
filters:
- name: Retry
args:
retries: 3
statuses: BAD_GATEWAY

针对不同的响应做重试,可配置如下参数:

  • retries: 重试次数
  • statuses: 需要重试的状态码,取值在 org.springframework.http.HttpStatus
  • methods: 需要重试的请求方法,取值在 org.springframework.http.HttpMethod
  • series: HTTP状态码系列,取值在 org.springframework.http.HttpStatus.Series

23 RequestSize GatewayFilter Factory

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spring:
cloud:
gateway:
routes:
- id: request_size_route
uri: http://localhost:8080/upload
predicates:
- Path=/upload
filters:
- name: RequestSize
args:
# 单位字节
maxSize: 5000000

为后端服务设置收到的最大请求包大小。如果请求大小超过设置的值,则返回 413 Payload Too Large 。默认值是5M

24 Modify Request Body GatewayFilter Factory

TIPS

该过滤器处于 BETA 状态,未来API可能会变化,生产环境请慎用。

可用于在Gateway将请求发送给后端微服务之前,修改请求体内容。该过滤器只能通过代码配置,不支持在配置文件设置。示例:

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@Bean
public RouteLocator routes(RouteLocatorBuilder builder) {
return builder.routes()
.route("rewrite_request_obj", r -> r.host("*.rewriterequestobj.org")
.filters(f -> f.prefixPath("/httpbin")
.modifyRequestBody(String.class, Hello.class, MediaType.APPLICATION_JSON_VALUE,
(exchange, s) -> return Mono.just(new Hello(s.toUpperCase())))).uri(uri))
.build();
}

static class Hello {
String message;

public Hello() { }

public Hello(String message) {
this.message = message;
}

public String getMessage() {
return message;
}

public void setMessage(String message) {
this.message = message;
}
}

25 Modify Response Body GatewayFilter Factory

TIPS

该过滤器处于 BETA 状态,未来API可能会变化,生产环境请慎用。

可用于修改响应体内容。该过滤器只能通过代码配置,不支持在配置文件设置。示例:

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@Bean
public RouteLocator routes(RouteLocatorBuilder builder) {
return builder.routes()
.route("rewrite_response_upper", r -> r.host("*.rewriteresponseupper.org")
.filters(f -> f.prefixPath("/httpbin")
.modifyResponseBody(String.class, String.class,
(exchange, s) -> Mono.just(s.toUpperCase()))).uri(uri)
.build();
}

26 Default Filters

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spring:
cloud:
gateway:
default-filters:
- AddResponseHeader=X-Response-Default-Foo, Default-Bar
- PrefixPath=/httpbin

如果你想为所有路由添加过滤器,可使用该属性。

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