Adapt WebFlux.fn auto-config to SPR-15536

Since SPR-15536, WebFlux.fn is now configured with `@EnableWebFlux`,
along the annotated controllers. Both `RouterFunction` and Controller
instances can now live within the same application and they share
the same web infrastructure.

This commit removes the custom auto-configuration for `RouterFunction`
and relies on `@EnableWebFlux` for that.

Closes gh-9165

spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/web/reactive/HttpHandlerAutoConfiguration.java

@@ -16,13 +16,9 @@
 
 package org.springframework.boot.autoconfigure.web.reactive;
 
-import java.util.List;
-
-import org.springframework.beans.factory.ObjectProvider;
 import org.springframework.boot.autoconfigure.AutoConfigureAfter;
 import org.springframework.boot.autoconfigure.AutoConfigureOrder;
 import org.springframework.boot.autoconfigure.EnableAutoConfiguration;
-import org.springframework.boot.autoconfigure.condition.ConditionalOnBean;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnClass;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnMissingBean;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnWebApplication;
@@ -30,17 +26,9 @@ import org.springframework.context.ApplicationContext;
 import org.springframework.context.annotation.Bean;
 import org.springframework.context.annotation.Configuration;
 import org.springframework.core.Ordered;
-import org.springframework.core.annotation.AnnotationAwareOrderComparator;
 import org.springframework.http.server.reactive.HttpHandler;
 import org.springframework.web.reactive.DispatcherHandler;
-import org.springframework.web.reactive.function.server.HandlerStrategies;
-import org.springframework.web.reactive.function.server.RouterFunction;
-import org.springframework.web.reactive.function.server.RouterFunctions;
-import org.springframework.web.reactive.result.view.ViewResolver;
-import org.springframework.web.server.WebFilter;
-import org.springframework.web.server.adapter.HttpWebHandlerAdapter;
 import org.springframework.web.server.adapter.WebHttpHandlerBuilder;
-import org.springframework.web.server.session.WebSessionManager;
 
 /**
  * {@link EnableAutoConfiguration Auto-configuration} for {@link HttpHandler}.
@@ -58,7 +46,6 @@ import org.springframework.web.server.session.WebSessionManager;
 public class HttpHandlerAutoConfiguration {
 
 	@Configuration
-	@ConditionalOnMissingBean(RouterFunction.class)
 	public static class AnnotationConfig {
 
 		private ApplicationContext applicationContext;
@@ -69,58 +56,7 @@ public class HttpHandlerAutoConfiguration {
 
 		@Bean
 		public HttpHandler httpHandler() {
-			return WebHttpHandlerBuilder.applicationContext(this.applicationContext)
-					.build();
-		}
-
-	}
-
-	@Configuration
-	@ConditionalOnBean(RouterFunction.class)
-	public static class FunctionalConfig {
-
-		private final List<WebFilter> webFilters;
-
-		private final WebSessionManager webSessionManager;
-
-		private HandlerStrategies.Builder handlerStrategiesBuilder;
-
-		private final List<ViewResolver> viewResolvers;
-
-		public FunctionalConfig(ObjectProvider<List<WebFilter>> webFilters,
-				ObjectProvider<WebSessionManager> webSessionManager,
-				ObjectProvider<HandlerStrategies.Builder> handlerStrategiesBuilder,
-				ObjectProvider<List<ViewResolver>> viewResolvers) {
-			this.webFilters = webFilters.getIfAvailable();
-			if (this.webFilters != null) {
-				AnnotationAwareOrderComparator.sort(this.webFilters);
-			}
-			this.webSessionManager = webSessionManager.getIfAvailable();
-			this.handlerStrategiesBuilder = handlerStrategiesBuilder.getIfAvailable();
-			this.viewResolvers = viewResolvers.getIfAvailable();
-		}
-
-		@Bean
-		public HttpHandler httpHandler(List<RouterFunction<?>> routerFunctions) {
-			routerFunctions.sort(new AnnotationAwareOrderComparator());
-			RouterFunction<?> routerFunction = routerFunctions.stream()
-					.reduce(RouterFunction::andOther).get();
-			if (this.handlerStrategiesBuilder == null) {
-				this.handlerStrategiesBuilder = HandlerStrategies.builder();
-			}
-			if (this.webFilters != null) {
-				this.webFilters.forEach(this.handlerStrategiesBuilder::webFilter);
-			}
-			if (this.viewResolvers != null) {
-				this.viewResolvers.forEach(this.handlerStrategiesBuilder::viewResolver);
-			}
-			HttpHandler httpHandler = RouterFunctions.toHttpHandler(routerFunction,
-					this.handlerStrategiesBuilder.build());
-			if (this.webSessionManager != null) {
-				((HttpWebHandlerAdapter) httpHandler)
-						.setSessionManager(this.webSessionManager);
-			}
-			return httpHandler;
+			return WebHttpHandlerBuilder.applicationContext(this.applicationContext).build();
 		}
 
 	}

spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/web/reactive/WebFluxAutoConfiguration.java

@@ -56,7 +56,6 @@ import org.springframework.web.reactive.config.ResourceHandlerRegistry;
 import org.springframework.web.reactive.config.ViewResolverRegistry;
 import org.springframework.web.reactive.config.WebFluxConfigurationSupport;
 import org.springframework.web.reactive.config.WebFluxConfigurer;
-import org.springframework.web.reactive.function.server.RouterFunction;
 import org.springframework.web.reactive.resource.AppCacheManifestTransformer;
 import org.springframework.web.reactive.resource.GzipResourceResolver;
 import org.springframework.web.reactive.resource.ResourceResolver;
@@ -79,7 +78,7 @@ import org.springframework.web.reactive.result.view.ViewResolver;
 @Configuration
 @ConditionalOnWebApplication(type = ConditionalOnWebApplication.Type.REACTIVE)
 @ConditionalOnClass(WebFluxConfigurer.class)
-@ConditionalOnMissingBean({ WebFluxConfigurationSupport.class, RouterFunction.class })
+@ConditionalOnMissingBean({ WebFluxConfigurationSupport.class })
 @AutoConfigureAfter(ReactiveWebServerAutoConfiguration.class)
 @AutoConfigureOrder(Ordered.HIGHEST_PRECEDENCE + 10)
 public class WebFluxAutoConfiguration {

spring-boot-autoconfigure/src/test/java/org/springframework/boot/autoconfigure/web/reactive/HttpHandlerAutoConfigurationTests.java

@@ -24,22 +24,13 @@ import org.springframework.boot.test.util.EnvironmentTestUtils;
 import org.springframework.boot.web.reactive.context.GenericReactiveWebApplicationContext;
 import org.springframework.context.annotation.Bean;
 import org.springframework.context.annotation.Configuration;
-import org.springframework.context.annotation.Import;
-import org.springframework.core.Ordered;
-import org.springframework.core.annotation.Order;
 import org.springframework.http.server.reactive.HttpHandler;
 import org.springframework.web.reactive.function.server.RequestPredicates;
 import org.springframework.web.reactive.function.server.RouterFunction;
 import org.springframework.web.reactive.function.server.RouterFunctions;
 import org.springframework.web.reactive.function.server.ServerResponse;
-import org.springframework.web.server.WebFilter;
-import org.springframework.web.server.WebHandler;
-import org.springframework.web.server.handler.FilteringWebHandler;
-import org.springframework.web.server.handler.WebHandlerDecorator;
 
 import static org.assertj.core.api.Assertions.assertThat;
-import static org.assertj.core.api.Assertions.fail;
-import static org.mockito.Mockito.mock;
 
 /**
  * Tests for {@link HttpHandlerAutoConfiguration}.
@@ -68,52 +59,6 @@ public class HttpHandlerAutoConfigurationTests {
 		assertThat(this.context.getBeansOfType(HttpHandler.class).size()).isEqualTo(1);
 	}
 
-	@Test
-	public void shouldConfigureHttpHandlerFunctional() {
-		load(FunctionalConfig.class);
-		assertThat(this.context.getBeansOfType(HttpHandler.class).size()).isEqualTo(1);
-	}
-
-	@Test
-	public void shouldConfigureWebFiltersAnnotation() {
-		load(AnnotationConfigWithWebFilters.class);
-
-		HttpHandler handler = this.context.getBean(HttpHandler.class);
-		assertThat(handler).isInstanceOf(WebHandler.class);
-		WebHandler webHandler = (WebHandler) handler;
-		while (webHandler instanceof WebHandlerDecorator) {
-			if (webHandler instanceof FilteringWebHandler) {
-				FilteringWebHandler filteringWebHandler = (FilteringWebHandler) webHandler;
-				assertThat(filteringWebHandler.getFilters()).containsExactly(
-						this.context.getBean("firstWebFilter", WebFilter.class),
-						this.context.getBean("aWebFilter", WebFilter.class),
-						this.context.getBean("lastWebFilter", WebFilter.class));
-				return;
-			}
-			webHandler = ((WebHandlerDecorator) webHandler).getDelegate();
-		}
-		fail("Did not find any FilteringWebHandler");
-	}
-
-	@Test
-	public void shouldConfigureWebFiltersFunctional() {
-		load(FunctionalConfigWithWebFilters.class);
-		assertThat(this.context.getBeansOfType(HttpHandler.class).size()).isEqualTo(1);
-		HttpHandler handler = this.context.getBean(HttpHandler.class);
-		assertThat(handler).isInstanceOf(WebHandler.class);
-		WebHandler webHandler = (WebHandler) handler;
-		while (webHandler instanceof WebHandlerDecorator) {
-			if (webHandler instanceof FilteringWebHandler) {
-				FilteringWebHandler filteringWebHandler = (FilteringWebHandler) webHandler;
-				assertThat(filteringWebHandler.getFilters()).containsExactly(
-						this.context.getBean("customWebFilter", WebFilter.class));
-				return;
-			}
-			webHandler = ((WebHandlerDecorator) webHandler).getDelegate();
-		}
-		fail("Did not find any FilteringWebHandler");
-	}
-
 	private void load(Class<?> config, String... environment) {
 		this.context = new GenericReactiveWebApplicationContext();
 		EnvironmentTestUtils.addEnvironment(this.context, environment);
@@ -124,55 +69,6 @@ public class HttpHandlerAutoConfigurationTests {
 		this.context.refresh();
 	}
 
-	@Configuration
-	@Import(WebFluxAutoConfiguration.class)
-	protected static class AnnotationConfigWithWebFilters {
-
-		@Bean
-		public WebFilter aWebFilter() {
-			return mock(WebFilter.class);
-		}
-
-		@Bean
-		@Order(Ordered.LOWEST_PRECEDENCE)
-		public WebFilter lastWebFilter() {
-			return mock(WebFilter.class);
-		}
-
-		@Bean
-		@Order(Ordered.HIGHEST_PRECEDENCE)
-		public WebFilter firstWebFilter() {
-			return mock(WebFilter.class);
-		}
-	}
-
-	@Configuration
-	protected static class FunctionalConfig {
-
-		@Bean
-		public RouterFunction<ServerResponse> routerFunction() {
-			return RouterFunctions.route(RequestPredicates.GET("/test"),
-					(serverRequest) -> null);
-		}
-
-	}
-
-	@Configuration
-	protected static class FunctionalConfigWithWebFilters {
-
-		@Bean
-		public RouterFunction<ServerResponse> routerFunction() {
-			return RouterFunctions.route(RequestPredicates.GET("/test"),
-					(serverRequest) -> null);
-		}
-
-		@Bean
-		public WebFilter customWebFilter() {
-			return (serverWebExchange, webFilterChain) -> null;
-		}
-
-	}
-
 	@Configuration
 	protected static class CustomHttpHandler {
 

spring-boot-samples/spring-boot-sample-webflux/src/main/java/sample/webflux/EchoHandler.java

@@ -0,0 +1,32 @@
+/*
+ * Copyright 2012-2017 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
+ *
+ *      http://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 sample.webflux;
+
+import reactor.core.publisher.Mono;
+
+import org.springframework.stereotype.Component;
+import org.springframework.web.reactive.function.server.ServerRequest;
+import org.springframework.web.reactive.function.server.ServerResponse;
+
+@Component
+public class EchoHandler {
+
+	public Mono<ServerResponse> echo(ServerRequest request) {
+		return ServerResponse.ok().body(request.bodyToMono(String.class), String.class);
+	}
+
+}

spring-boot-samples/spring-boot-sample-webflux/src/main/java/sample/webflux/SampleWebFluxApplication.java

@@ -18,6 +18,12 @@ package sample.webflux;
 
 import org.springframework.boot.SpringApplication;
 import org.springframework.boot.autoconfigure.SpringBootApplication;
+import org.springframework.context.annotation.Bean;
+import org.springframework.web.reactive.function.server.RouterFunction;
+import org.springframework.web.reactive.function.server.ServerResponse;
+
+import static org.springframework.web.reactive.function.server.RequestPredicates.POST;
+import static org.springframework.web.reactive.function.server.RouterFunctions.route;
 
 @SpringBootApplication
 public class SampleWebFluxApplication {
@@ -26,4 +32,9 @@ public class SampleWebFluxApplication {
 		SpringApplication.run(SampleWebFluxApplication.class);
 	}
 
+	@Bean
+	public RouterFunction<ServerResponse> monoRouterFunction(EchoHandler echoHandler) {
+		return route(POST("/echo"), echoHandler::echo);
+	}
+
 }

spring-boot-samples/spring-boot-sample-webflux/src/test/java/sample/webflux/SampleWebFluxApplicationTests.java

@@ -18,6 +18,7 @@ package sample.webflux;
 
 import org.junit.Test;
 import org.junit.runner.RunWith;
+import reactor.core.publisher.Mono;
 
 import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.boot.test.context.SpringBootTest;
@@ -44,4 +45,14 @@ public class SampleWebFluxApplicationTests {
 				.expectBody(String.class).isEqualTo("Hello World");
 	}
 
+	@Test
+	public void testEcho() throws Exception {
+		this.webClient.post().uri("/echo")
+				.contentType(MediaType.TEXT_PLAIN)
+				.accept(MediaType.TEXT_PLAIN)
+				.body(Mono.just("Hello WebFlux!"), String.class)
+				.exchange()
+				.expectBody(String.class).isEqualTo("Hello WebFlux!");
+	}
+
 }