AddRequestHeadersIfNotPresent 篩檢程式

AddRequestHeadersIfNotPresent 篩檢程式會採用以冒號分隔的 name 和 value 配對集合。以下範例設定 AddRequestHeadersIfNotPresent 篩檢程式

application.yml
spring:
  cloud:
    gateway:
      mvc:
        routes:
        - id: add_request_headers_route
          uri: https://example.org
          filters:
          - AddRequestHeadersIfNotPresent=X-Request-Color-1:blue,X-Request-Color-2:green
GatewaySampleApplication.java
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> gatewayRouterFunctionsAddReqHeader() {
        return route(GET("/red"), http("https://example.org"))
                .before(addRequestHeadersIfNotPresent("X-Request-Color-1:blue","X-Request-Color-2:green"));
    }
}

此列表將 2 個標頭 X-Request-Color-1:blue 和 X-Request-Color-2:green 新增至下游請求的標頭，以用於所有符合的請求。這與 AddRequestHeader 的運作方式類似，但不像 AddRequestHeader，它只會在標頭尚不存在時執行此操作。否則，將傳送用戶端請求中的原始值。

此外，若要設定多值標頭，請多次使用標頭名稱，例如 addRequestHeadersIfNotPresent("X-Request-Color-1:blue","X-Request-Color-1:green")。

AddRequestHeadersIfNotPresent 也支援用於比對路徑或主機的 URI 變數。URI 變數可用於值中，並在執行階段展開。以下範例設定使用變數的 AddRequestHeadersIfNotPresent 篩檢程式

GatewaySampleApplication.java
@Configuration
class RouteConfiguration {

    @Bean
    public RouterFunction<ServerResponse> gatewayRouterFunctionsAddReqHeader() {
        return route(GET("/red/{segment}"), http("https://example.org"))
                .before(addRequestHeadersIfNotPresent("X-Request-red", "blue-{segment}"));
    }
}
application.yml
spring:
  cloud:
    gateway:
      routes:
      - id: add_request_header_route
        uri: https://example.org
        predicates:
        - Path=/red/{segment}
        filters:
        - AddRequestHeadersIfNotPresent=X-Request-Red:Blue-{segment}