Apply RSocket server customizers to netty web server

This commit applies `ServerRSocketFactoryCustomizer` beans to RSocket
setups when the RSocket server is being plugged into an existing Reactor
Netty web server.

Fixes gh-18208

spring-boot-project/spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/rsocket/RSocketServerAutoConfiguration.java

@@ -68,10 +68,13 @@ public class RSocketServerAutoConfiguration {
 	static class WebFluxServerAutoConfiguration {
 
 		@Bean
+		@ConditionalOnMissingBean
 		RSocketWebSocketNettyRouteProvider rSocketWebsocketRouteProvider(RSocketProperties properties,
-				RSocketMessageHandler messageHandler) {
-			return new RSocketWebSocketNettyRouteProvider(properties.getServer().getMappingPath(),
-					messageHandler.responder());
+				RSocketMessageHandler messageHandler, ObjectProvider<ServerRSocketFactoryCustomizer> customizers) {
+			RSocketWebSocketNettyRouteProvider routeProvider = new RSocketWebSocketNettyRouteProvider(
+					properties.getServer().getMappingPath(), messageHandler.responder());
+			routeProvider.setCustomizers(customizers.orderedStream().collect(Collectors.toList()));
+			return routeProvider;
 		}
 
 	}

spring-boot-project/spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/rsocket/RSocketWebSocketNettyRouteProvider.java

@@ -16,12 +16,16 @@
 
 package org.springframework.boot.autoconfigure.rsocket;
 
+import java.util.Collections;
+import java.util.List;
+
 import io.rsocket.RSocketFactory;
 import io.rsocket.SocketAcceptor;
 import io.rsocket.transport.ServerTransport;
 import io.rsocket.transport.netty.server.WebsocketRouteTransport;
 import reactor.netty.http.server.HttpServerRoutes;
 
+import org.springframework.boot.rsocket.server.ServerRSocketFactoryCustomizer;
 import org.springframework.boot.web.embedded.netty.NettyRouteProvider;
 
 /**
@@ -35,15 +39,24 @@ class RSocketWebSocketNettyRouteProvider implements NettyRouteProvider {
 
 	private final SocketAcceptor socketAcceptor;
 
+	private List<ServerRSocketFactoryCustomizer> customizers = Collections.emptyList();
+
 	RSocketWebSocketNettyRouteProvider(String mappingPath, SocketAcceptor socketAcceptor) {
 		this.mappingPath = mappingPath;
 		this.socketAcceptor = socketAcceptor;
 	}
 
+	void setCustomizers(List<ServerRSocketFactoryCustomizer> customizers) {
+		this.customizers = customizers;
+	}
+
 	@Override
 	public HttpServerRoutes apply(HttpServerRoutes httpServerRoutes) {
-		ServerTransport.ConnectionAcceptor acceptor = RSocketFactory.receive().acceptor(this.socketAcceptor)
-				.toConnectionAcceptor();
+		RSocketFactory.ServerRSocketFactory server = RSocketFactory.receive();
+		for (ServerRSocketFactoryCustomizer customizer : this.customizers) {
+			server = customizer.apply(server);
+		}
+		ServerTransport.ConnectionAcceptor acceptor = server.acceptor(this.socketAcceptor).toConnectionAcceptor();
 		return httpServerRoutes.ws(this.mappingPath, WebsocketRouteTransport.newHandler(acceptor));
 	}
 

spring-boot-project/spring-boot-autoconfigure/src/test/java/org/springframework/boot/autoconfigure/rsocket/RSocketServerAutoConfigurationTests.java

@@ -86,6 +86,15 @@ class RSocketServerAutoConfigurationTests {
 				.getBeanNames(RSocketServerBootstrap.class).containsExactly("customServerBootstrap"));
 	}
 
+	@Test
+	void shouldUseCustomNettyRouteProvider() {
+		reactiveWebContextRunner().withUserConfiguration(CustomNettyRouteProviderConfig.class)
+				.withPropertyValues("spring.rsocket.server.transport=websocket",
+						"spring.rsocket.server.mapping-path=/rsocket")
+				.run((context) -> assertThat(context).getBeanNames(RSocketWebSocketNettyRouteProvider.class)
+						.containsExactly("customNettyRouteProvider"));
+	}
+
 	private ApplicationContextRunner contextRunner() {
 		return new ApplicationContextRunner().withUserConfiguration(BaseConfiguration.class)
 				.withConfiguration(AutoConfigurations.of(RSocketServerAutoConfiguration.class));
@@ -119,4 +128,14 @@ class RSocketServerAutoConfigurationTests {
 
 	}
 
+	@Configuration(proxyBeanMethods = false)
+	static class CustomNettyRouteProviderConfig {
+
+		@Bean
+		RSocketWebSocketNettyRouteProvider customNettyRouteProvider() {
+			return mock(RSocketWebSocketNettyRouteProvider.class);
+		}
+
+	}
+
 }

spring-boot-project/spring-boot-autoconfigure/src/test/java/org/springframework/boot/autoconfigure/rsocket/RSocketWebSocketNettyRouteProviderTests.java

@@ -28,6 +28,7 @@ import org.springframework.boot.autoconfigure.jackson.JacksonAutoConfiguration;
 import org.springframework.boot.autoconfigure.web.reactive.HttpHandlerAutoConfiguration;
 import org.springframework.boot.autoconfigure.web.reactive.WebFluxAutoConfiguration;
 import org.springframework.boot.autoconfigure.web.reactive.error.ErrorWebFluxAutoConfiguration;
+import org.springframework.boot.rsocket.server.ServerRSocketFactoryCustomizer;
 import org.springframework.boot.test.context.runner.ReactiveWebApplicationContextRunner;
 import org.springframework.boot.web.embedded.netty.NettyReactiveWebServerFactory;
 import org.springframework.boot.web.reactive.context.AnnotationConfigReactiveWebServerApplicationContext;
@@ -76,6 +77,7 @@ class RSocketWebSocketNettyRouteProviderTests {
 					WebTestClient client = createWebTestClient(serverContext.getWebServer());
 					client.get().uri("/protocol").exchange().expectStatus().isOk().expectBody().jsonPath("name",
 							"http");
+					assertThat(WebConfiguration.customizerCallCount).isEqualTo(1);
 				});
 	}
 
@@ -93,6 +95,8 @@ class RSocketWebSocketNettyRouteProviderTests {
 	@Configuration(proxyBeanMethods = false)
 	static class WebConfiguration {
 
+		static int customizerCallCount = 0;
+
 		@Bean
 		WebController webController() {
 			return new WebController();
@@ -105,6 +109,14 @@ class RSocketWebSocketNettyRouteProviderTests {
 			return serverFactory;
 		}
 
+		@Bean
+		ServerRSocketFactoryCustomizer myRSocketFactoryCustomizer() {
+			return (server) -> {
+				customizerCallCount++;
+				return server;
+			};
+		}
+
 	}
 
 	@Controller