Add support for select function paramters for gateway kotlin dsl (#98)

spring-cloud-gateway-sample/src/main/java/org/springframework/cloud/gateway/sample/GatewaySampleApplication.java

@@ -23,6 +23,7 @@ import org.springframework.boot.autoconfigure.EnableAutoConfiguration;
 import org.springframework.cloud.gateway.route.RouteLocator;
 import org.springframework.cloud.gateway.route.Routes;
 import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Import;
 import org.springframework.web.reactive.function.BodyInserters;
 import org.springframework.web.reactive.function.server.RequestPredicates;
 import org.springframework.web.reactive.function.server.RouterFunction;
@@ -39,10 +40,12 @@ import static org.springframework.tuple.TupleBuilder.tuple;
  */
 @SpringBootConfiguration
 @EnableAutoConfiguration
+@Import(AdditionalRoutes.class)
 public class GatewaySampleApplication {
 
 	@Bean
 	public RouteLocator customRouteLocator(ThrottleGatewayFilterFactory throttle) {
+		//@formatter:off
 		return Routes.locator()
 				.route("test")
 					.predicate(host("**.abc.org").and(path("/image/png")))
@@ -61,6 +64,7 @@ public class GatewaySampleApplication {
 							"refillUnit", "SECONDS")))
 					.uri("http://httpbin.org:80")
 				.build();
+		////@formatter:on
 	}
 
 	@Bean

spring-cloud-gateway-sample/src/main/kotlin/org/springframework/cloud/gateway/sample/AdditionalRoutes.kt

@@ -0,0 +1,23 @@
+package org.springframework.cloud.gateway.sample
+
+import org.springframework.cloud.gateway.filter.factory.GatewayFilters.addResponseHeader
+import org.springframework.cloud.gateway.handler.predicate.RoutePredicates.host
+import org.springframework.cloud.gateway.handler.predicate.RoutePredicates.path
+import org.springframework.cloud.gateway.route.RouteLocator
+import org.springframework.cloud.gateway.route.gateway
+import org.springframework.context.annotation.Bean
+import org.springframework.context.annotation.Configuration
+
+@Configuration
+class AdditionalRoutes {
+
+	@Bean
+	fun additionalRouteLocator(): RouteLocator = gateway {
+		route(id = "test-kotlin") {
+			uri("http://httpbin.org:80")
+			predicate(host("kotlin.abc.org") and path("/image/png"))
+			add(addResponseHeader("X-TestHeader", "foobar"))
+		}
+	}
+
+}