Add resource redirection to WebFlux functional router

See gh-27257

spring-webflux/src/test/java/org/springframework/web/reactive/function/server/RouterFunctionBuilderTests.java

@@ -39,6 +39,7 @@ import org.springframework.web.testfixture.server.MockServerWebExchange;
 
 import static org.assertj.core.api.Assertions.assertThat;
 import static org.springframework.web.reactive.function.server.RequestPredicates.HEAD;
+import static org.springframework.web.reactive.function.server.RequestPredicates.path;
 
 /**
  * @author Arjen Poutsma
@@ -102,6 +103,27 @@ class RouterFunctionBuilderTests {
 
 	}
 
+	@Test
+	void resource() {
+		Resource resource = new ClassPathResource("/org/springframework/web/reactive/function/server/response.txt");
+		assertThat(resource.exists()).isTrue();
+
+		RouterFunction<ServerResponse> route = RouterFunctions.route()
+				.resource(path("/test"), resource)
+				.build();
+
+		MockServerHttpRequest mockRequest = MockServerHttpRequest.get("https://localhost/test").build();
+		ServerRequest resourceRequest = new DefaultServerRequest(MockServerWebExchange.from(mockRequest), Collections.emptyList());
+
+		Mono<HttpStatusCode> responseMono = route.route(resourceRequest)
+				.flatMap(handlerFunction -> handlerFunction.handle(resourceRequest))
+				.map(ServerResponse::statusCode);
+
+		StepVerifier.create(responseMono)
+				.expectNext(HttpStatus.OK)
+				.verifyComplete();
+	}
+
 	@Test
 	void resources() {
 		Resource resource = new ClassPathResource("/org/springframework/web/reactive/function/server/");

spring-webflux/src/test/kotlin/org/springframework/web/reactive/function/server/CoRouterFunctionDslTests.kt

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2023 the original author or authors.
+ * Copyright 2002-2024 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.
@@ -93,16 +93,6 @@ class CoRouterFunctionDslTests {
 				.verifyComplete()
 	}
 
-	@Test
-	fun resourceByPath() {
-		val mockRequest = get("https://example.com/org/springframework/web/reactive/function/response.txt")
-				.build()
-		val request = DefaultServerRequest(MockServerWebExchange.from(mockRequest), emptyList())
-		StepVerifier.create(sampleRouter().route(request))
-				.expectNextCount(1)
-				.verifyComplete()
-	}
-
 	@Test
 	fun method() {
 		val mockRequest = patch("https://example.com/")
@@ -124,6 +114,24 @@ class CoRouterFunctionDslTests {
 
 	@Test
 	fun resource() {
+		val mockRequest = get("https://example.com/response2.txt").build()
+		val request = DefaultServerRequest(MockServerWebExchange.from(mockRequest), emptyList())
+		StepVerifier.create(sampleRouter().route(request))
+			.expectNextCount(1)
+			.verifyComplete()
+	}
+
+	@Test
+	fun resources() {
+		val mockRequest = get("https://example.com/resources/response.txt").build()
+		val request = DefaultServerRequest(MockServerWebExchange.from(mockRequest), emptyList())
+		StepVerifier.create(sampleRouter().route(request))
+			.expectNextCount(1)
+			.verifyComplete()
+	}
+
+	@Test
+	fun resourcesLookupFunction() {
 		val mockRequest = get("https://example.com/response.txt").build()
 		val request = DefaultServerRequest(MockServerWebExchange.from(mockRequest), emptyList())
 		StepVerifier.create(sampleRouter().route(request))
@@ -305,8 +313,9 @@ class CoRouterFunctionDslTests {
 			GET("/api/foo/", ::handle)
 		}
 		headers({ it.header("bar").isNotEmpty() }, ::handle)
-		resources("/org/springframework/web/reactive/function/**",
-				ClassPathResource("/org/springframework/web/reactive/function/response.txt"))
+		resource(path("/response2.txt"), ClassPathResource("/org/springframework/web/reactive/function/response.txt"))
+		resources("/resources/**",
+			ClassPathResource("/org/springframework/web/reactive/function/"))
 		resources {
 			if (it.path() == "/response.txt") {
 				ClassPathResource("/org/springframework/web/reactive/function/response.txt")

spring-webflux/src/test/kotlin/org/springframework/web/reactive/function/server/RouterFunctionDslTests.kt

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2023 the original author or authors.
+ * Copyright 2002-2024 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.
@@ -91,16 +91,6 @@ class RouterFunctionDslTests {
 				.verifyComplete()
 	}
 
-	@Test
-	fun resourceByPath() {
-		val mockRequest = get("https://example.com/org/springframework/web/reactive/function/response.txt")
-				.build()
-		val request = DefaultServerRequest(MockServerWebExchange.from(mockRequest), emptyList())
-		StepVerifier.create(sampleRouter().route(request))
-				.expectNextCount(1)
-				.verifyComplete()
-	}
-
 	@Test
 	fun method() {
 		val mockRequest = patch("https://example.com/")
@@ -122,6 +112,24 @@ class RouterFunctionDslTests {
 
 	@Test
 	fun resource() {
+		val mockRequest = get("https://example.com/response2.txt").build()
+		val request = DefaultServerRequest(MockServerWebExchange.from(mockRequest), emptyList())
+		StepVerifier.create(sampleRouter().route(request))
+			.expectNextCount(1)
+			.verifyComplete()
+	}
+
+	@Test
+	fun resources() {
+		val mockRequest = get("https://example.com/resources/response.txt").build()
+		val request = DefaultServerRequest(MockServerWebExchange.from(mockRequest), emptyList())
+		StepVerifier.create(sampleRouter().route(request))
+			.expectNextCount(1)
+			.verifyComplete()
+	}
+
+	@Test
+	fun resourcesLookupFunction() {
 		val mockRequest = get("https://example.com/response.txt").build()
 		val request = DefaultServerRequest(MockServerWebExchange.from(mockRequest), emptyList())
 		StepVerifier.create(sampleRouter().route(request))
@@ -237,8 +245,9 @@ class RouterFunctionDslTests {
 			GET("/api/foo/", ::handle)
 		}
 		headers({ it.header("bar").isNotEmpty() }, ::handle)
-		resources("/org/springframework/web/reactive/function/**",
-				ClassPathResource("/org/springframework/web/reactive/function/response.txt"))
+		resource(path("/response2.txt"), ClassPathResource("/org/springframework/web/reactive/function/response.txt"))
+		resources("/resources/**",
+				ClassPathResource("/org/springframework/web/reactive/function/"))
 		resources {
 			if (it.path() == "/response.txt") {
 				Mono.just(ClassPathResource("/org/springframework/web/reactive/function/response.txt"))