`AddRequestHeadersIfNotPresent` 過濾器

AddRequestHeadersIfNotPresent 過濾器接受由冒號分隔的 `名稱` 和 `值` 對集合。以下示例配置了一個 `AddRequestHeadersIfNotPresent` 過濾器

application.yml

spring:
  cloud:
    gateway:
      mvc:
        routes:
        - id: add_request_headers_route_inp
          uri: https://example.org
          predicates:
          - Path=/red
          filters:
          - AddRequestHeadersIfNotPresent=X-Request-Color-1:blue,X-Request-Color-2:green

GatewaySampleApplication.java

import static org.springframework.cloud.gateway.server.mvc.filter.BeforeFilterFunctions.uri;
import static org.springframework.cloud.gateway.server.mvc.filter.BeforeFilterFunctions.addRequestHeadersIfNotPresent;
import static org.springframework.cloud.gateway.server.mvc.handler.GatewayRouterFunctions.route;
import static org.springframework.cloud.gateway.server.mvc.handler.HandlerFunctions.http;

@Configuration
class RouteConfiguration {

    @Bean
    public RouterFunction<ServerResponse> gatewayRouterFunctionsAddReqHeaderInp() {
        return route("add_request_headers_route_inp")
            .GET("/red", http())
            .before(uri("https://example.org"))
            .before(addRequestHeadersIfNotPresent("X-Request-Color-1:blue","X-Request-Color-2:green"));
    }
}

此列表為所有匹配的請求向下遊請求的頭部添加了兩個頭部 X-Request-Color-1:blue 和 X-Request-Color-2:green。這類似於 AddRequestHeader 的工作方式，但與 AddRequestHeader 不同的是，它只會在頭部尚不存在時新增。否則，將傳送客戶端請求中的原始值。

此外，要設定一個多值頭部，可以多次使用頭部名稱，例如 addRequestHeadersIfNotPresent("X-Request-Color-1:blue","X-Request-Color-1:green")。

AddRequestHeadersIfNotPresent 也支援用於匹配路徑或主機的 URI 變數。URI 變數可以在值中使用，並在執行時展開。以下示例配置了一個使用變數的 AddRequestHeadersIfNotPresent 過濾器

GatewaySampleApplication.java

import static org.springframework.cloud.gateway.server.mvc.filter.BeforeFilterFunctions.addRequestHeadersIfNotPresent;
import static org.springframework.cloud.gateway.server.mvc.filter.BeforeFilterFunctions.uri;
import static org.springframework.cloud.gateway.server.mvc.handler.GatewayRouterFunctions.route;
import static org.springframework.cloud.gateway.server.mvc.handler.HandlerFunctions.http;

@Configuration
class RouteConfiguration {

    @Bean
    public RouterFunction<ServerResponse> gatewayRouterFunctionsAddReqHeaderInp() {
        return route("add_request_header_route_inp")
            .GET("/red/{segment}", http())
            .before(uri("https://example.org"))
            .before(addRequestHeadersIfNotPresent("X-Request-red", "blue-{segment}"));
    }
}

application.yml

spring:
  cloud:
    gateway:
      routes:
      - id: add_request_header_route_inp
        uri: https://example.org
        predicates:
        - Path=/red/{segment}
        filters:
        - AddRequestHeadersIfNotPresent=X-Request-Red:Blue-{segment}

AddRequestHeadersIfNotPresent 過濾器

`AddRequestHeadersIfNotPresent` 過濾器