Add post filter example

src/main/java/org/springframework/cloud/gateway/GatewayController.java

@@ -2,6 +2,7 @@ package org.springframework.cloud.gateway;
 
 import java.util.Optional;
 
+import org.springframework.core.io.buffer.DataBuffer;
 import org.springframework.http.server.reactive.ServerHttpRequest;
 import org.springframework.http.server.reactive.ServerHttpResponse;
 import org.springframework.web.bind.annotation.GetMapping;
@@ -16,6 +17,7 @@ import reactor.core.publisher.Flux;
  * @author Spencer Gibb
  */
 @RestController
+@SuppressWarnings("unused")
 public class GatewayController {
 
 	private final WebClient webClient;
@@ -38,7 +40,8 @@ public class GatewayController {
 			ServerHttpResponse response = exchange.getResponse();
 			response.getHeaders().putAll(clientResponse.headers().asHttpHeaders());
 			response.setStatusCode(clientResponse.statusCode());
-			return response.writeWith(clientResponse.body((inputMessage, context) -> inputMessage.getBody()));
+			Flux<DataBuffer> body = clientResponse.body((inputMessage, context) -> inputMessage.getBody());
+			return response.writeWith(body);
 		});
 	}
 }

src/main/java/org/springframework/cloud/gateway/SpringCloudGatewayApplication.java

@@ -1,16 +1,23 @@
 package org.springframework.cloud.gateway;
 
+import org.apache.commons.logging.Log;
+import org.apache.commons.logging.LogFactory;
 import org.springframework.boot.SpringApplication;
 import org.springframework.boot.autoconfigure.SpringBootApplication;
 import org.springframework.context.annotation.Bean;
 import org.springframework.core.annotation.Order;
 import org.springframework.http.client.reactive.ReactorClientHttpConnector;
 import org.springframework.web.client.reactive.WebClient;
+import org.springframework.web.server.ServerWebExchange;
 import org.springframework.web.server.WebFilter;
 
+import reactor.core.publisher.Mono;
+
 @SpringBootApplication
 public class SpringCloudGatewayApplication {
 
+	private static final Log log = LogFactory.getLog(SpringCloudGatewayApplication.class);
+
 	@Bean
 	public WebClient webClient() {
 		return WebClient.builder(new ReactorClientHttpConnector()).build();
@@ -21,6 +28,7 @@ public class SpringCloudGatewayApplication {
 	@Order(500)
 	public WebFilter findRouteFilter() {
 		return (exchange, chain) -> {
+			log.info("findRoutFilter start");
 			exchange.getAttributes().put("requestUrl", "http://httpbin.org/get");
 			return chain.filter(exchange);
 		};
@@ -30,11 +38,27 @@ public class SpringCloudGatewayApplication {
 	@Order(501)
 	public WebFilter modifyResponseFilter() {
 		return (exchange, chain) -> {
+			log.info("modifyResponseFilter start");
 			exchange.getResponse().getHeaders().add("X-My-Custom", "MyCustomValue");
 			return chain.filter(exchange);
 		};
 	}
 
+	@Bean
+	@Order(502)
+	public WebFilter postFilter() {
+		return (exchange, chain) -> {
+			log.info("postFilter start");
+			return chain.filter(exchange).then(postFilterWork(exchange));
+		};
+	}
+
+	private static Mono<Void> postFilterWork(ServerWebExchange exchange) {
+		log.info("postFilterWork");
+		exchange.getResponse().getHeaders().add("X-Post-Header", "AddedAfterRoute");
+		return Mono.empty();
+	}
+
 	public static void main(String[] args) {
 		SpringApplication.run(SpringCloudGatewayApplication.class, args);
 	}