Adds AfterFilterFunctions.removeResponseHeader()

See gh-2949

spring-cloud-gateway-server-mvc/src/main/java/org/springframework/cloud/gateway/server/mvc/filter/AfterFilterFunctions.java

@@ -36,6 +36,13 @@ public interface AfterFilterFunctions {
 		};
 	}
 
+	static BiFunction<ServerRequest, ServerResponse, ServerResponse> removeResponseHeader(String name) {
+		return (request, response) -> {
+			response.headers().remove(name);
+			return response;
+		};
+	}
+
 	static BiFunction<ServerRequest, ServerResponse, ServerResponse> setResponseHeader(String name, String value) {
 		return (request, response) -> {
 			String expandedValue = MvcUtils.expand(request, value);

spring-cloud-gateway-server-mvc/src/test/java/org/springframework/cloud/gateway/server/mvc/ServerMvcIntegrationTests.java

@@ -70,6 +70,7 @@ import org.springframework.web.servlet.function.ServerResponse;
 
 import static org.assertj.core.api.Assertions.assertThat;
 import static org.springframework.cloud.gateway.server.mvc.filter.AfterFilterFunctions.addResponseHeader;
+import static org.springframework.cloud.gateway.server.mvc.filter.AfterFilterFunctions.removeResponseHeader;
 import static org.springframework.cloud.gateway.server.mvc.filter.AfterFilterFunctions.setResponseHeader;
 import static org.springframework.cloud.gateway.server.mvc.filter.AfterFilterFunctions.setStatus;
 import static org.springframework.cloud.gateway.server.mvc.filter.BeforeFilterFunctions.preserveHost;
@@ -426,6 +427,15 @@ public class ServerMvcIntegrationTests {
 				});
 	}
 
+	@Test
+	public void removeResponseHeaderWorks() {
+		restClient.get().uri("/anything/removeresponseheader").header("test", "removeresponseheader").exchange()
+				.expectStatus().isOk().expectBody(Map.class).consumeWith(res -> {
+					HttpHeaders headers = res.getResponseHeaders();
+					assertThat(headers).doesNotContainKey("X-Test");
+				});
+	}
+
 	@SpringBootConfiguration
 	@EnableAutoConfiguration
 	@LoadBalancerClient(name = "httpbin", configuration = TestLoadBalancerConfig.Httpbin.class)
@@ -734,6 +744,19 @@ public class ServerMvcIntegrationTests {
 			// @formatter:on
 		}
 
+		@Bean
+		public RouterFunction<ServerResponse> gatewayRouterFunctionsRemoveResponseHeader() {
+			// @formatter:off
+			return route("testremoveresponseheader")
+					.GET("/anything/removeresponseheader", header("test", "removeresponseheader"), http())
+					.before(new HttpbinUriResolver())
+					// reverse order for "post" filters
+					.after(removeResponseHeader("X-Test"))
+					.after(addResponseHeader("X-Test", "value1"))
+					.build();
+			// @formatter:on
+		}
+
 	}
 
 	@RestController