Handle URL Connection file not found 404

Fixes gh-3451

Author: spencergibb

spring-cloud-gateway-server-mvc/src/main/java/org/springframework/cloud/gateway/server/mvc/handler/RestClientProxyExchange.java

@@ -16,6 +16,7 @@
 
 package org.springframework.cloud.gateway.server.mvc.handler;
 
+import java.io.FileNotFoundException;
 import java.io.IOException;
 import java.io.InputStream;
 import java.io.OutputStream;
@@ -69,9 +70,15 @@ private static int copyBody(Request request, OutputStream outputStream) throws I
 	}
 
 	private ServerResponse doExchange(Request request, ClientHttpResponse clientResponse) throws IOException {
-		InputStream body = clientResponse.getBody();
-		// put the body input stream in a request attribute so filters can read it.
-		MvcUtils.putAttribute(request.getServerRequest(), MvcUtils.CLIENT_RESPONSE_INPUT_STREAM_ATTR, body);
+		try {
+			InputStream body = clientResponse.getBody();
+			// put the body input stream in a request attribute so filters can read it.
+			MvcUtils.putAttribute(request.getServerRequest(), MvcUtils.CLIENT_RESPONSE_INPUT_STREAM_ATTR, body);
+		}
+		catch (FileNotFoundException e) {
+			// if using SimpleClientHttpRequestFactory
+			return ServerResponse.notFound().build();
+		}
 		ServerResponse serverResponse = GatewayServerResponse.status(clientResponse.getStatusCode())
 			.build((req, httpServletResponse) -> {
 				try (clientResponse) {

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

@@ -275,12 +275,12 @@ public void stripPrefixPostWorks() {
 	public void setStatusGatewayRouterFunctionWorks() {
 		restClient.get()
 			.uri("/status/201")
+			.header("Host", "www.setstatus.org")
 			.exchange()
 			.expectStatus()
 			.isEqualTo(HttpStatus.TOO_MANY_REQUESTS)
 			.expectHeader()
-			.valueEquals("x-status", "201"); // .expectBody(String.class).isEqualTo("Failed
-												// with 201");
+			.valueEquals("x-status", "201");
 	}
 
 	@Test
@@ -981,6 +981,11 @@ public void clientResponseBodyAttributeWorks() {
 			});
 	}
 
+	@Test
+	public void notFoundWorks() {
+		restClient.get().uri("/status/404").header("Host", "www.notfound.org").exchange().expectStatus().isNotFound();
+	}
+
 	@SpringBootConfiguration
 	@EnableAutoConfiguration
 	@LoadBalancerClient(name = "httpbin", configuration = TestLoadBalancerConfig.Httpbin.class)
@@ -1032,7 +1037,7 @@ public RouterFunction<ServerResponse> gatewayRouterFunctionsAddReqHeader() {
 		public RouterFunction<ServerResponse> gatewayRouterFunctionsSetStatusAndAddRespHeader() {
 			// @formatter:off
 			return route("testsetstatus")
-					.GET("/status/{status}", http())
+					.GET("/status/{status}", host("**.setstatus.org"), http())
 					.before(new HttpbinUriResolver())
 					.after(setStatus(HttpStatus.TOO_MANY_REQUESTS))
 					.after(addResponseHeader("X-Status", "{status}"))
@@ -1600,6 +1605,16 @@ public RouterFunction<ServerResponse> gatewayRouterFunctionsReadResponseBody() {
 			// @formatter:on
 		}
 
+		@Bean
+		public RouterFunction<ServerResponse> gatewayRouterFunctions404() {
+			// @formatter:off
+			return route("testnotfound")
+					.GET("/status/404", host("**.notfound.org"), http())
+					.before(new HttpbinUriResolver())
+					.build();
+			// @formatter:on
+		}
+
 		@Bean
 		public FilterRegistrationBean myFilter() {
 			FilterRegistrationBean<MyFilter> reg = new FilterRegistrationBean<>(new MyFilter());

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

@@ -0,0 +1,80 @@
+/*
+ * Copyright 2013-2023 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.springframework.cloud.gateway.server.mvc;
+
+import org.junit.jupiter.api.Test;
+
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.boot.SpringBootConfiguration;
+import org.springframework.boot.autoconfigure.EnableAutoConfiguration;
+import org.springframework.boot.test.context.SpringBootTest;
+import org.springframework.boot.test.context.SpringBootTest.WebEnvironment;
+import org.springframework.boot.test.web.server.LocalServerPort;
+import org.springframework.cloud.gateway.server.mvc.test.HttpbinTestcontainers;
+import org.springframework.cloud.gateway.server.mvc.test.HttpbinUriResolver;
+import org.springframework.cloud.gateway.server.mvc.test.TestLoadBalancerConfig;
+import org.springframework.cloud.gateway.server.mvc.test.client.TestRestClient;
+import org.springframework.cloud.loadbalancer.annotation.LoadBalancerClient;
+import org.springframework.context.annotation.Bean;
+import org.springframework.test.context.ContextConfiguration;
+import org.springframework.web.servlet.function.RouterFunction;
+import org.springframework.web.servlet.function.ServerResponse;
+
+import static org.springframework.cloud.gateway.server.mvc.handler.GatewayRouterFunctions.route;
+import static org.springframework.cloud.gateway.server.mvc.handler.HandlerFunctions.http;
+import static org.springframework.cloud.gateway.server.mvc.predicate.GatewayRequestPredicates.host;
+
+@SuppressWarnings("unchecked")
+@SpringBootTest(properties = { "spring.cloud.gateway.mvc.http-client.type=autodetect" },
+		webEnvironment = WebEnvironment.RANDOM_PORT)
+@ContextConfiguration(initializers = HttpbinTestcontainers.class)
+public class SimpleHttpClientIntegrationTests {
+
+	static {
+		// if set type to autodetect above
+		System.setProperty("sun.net.http.allowRestrictedHeaders", "true");
+	}
+
+	@LocalServerPort
+	int port;
+
+	@Autowired
+	TestRestClient restClient;
+
+	@Test
+	public void simpleHttpClientNotFoundWorks() {
+		restClient.get().uri("/status/404").header("Host", "www.notfound.org").exchange().expectStatus().isNotFound();
+	}
+
+	@SpringBootConfiguration
+	@EnableAutoConfiguration
+	@LoadBalancerClient(name = "httpbin", configuration = TestLoadBalancerConfig.Httpbin.class)
+	protected static class TestConfiguration {
+
+		@Bean
+		public RouterFunction<ServerResponse> gatewayRouterFunctions404() {
+			// @formatter:off
+			return route("testnotfound")
+					.GET("/status/404", host("**.notfound.org"), http())
+					.before(new HttpbinUriResolver())
+					.build();
+			// @formatter:on
+		}
+
+	}
+
+}