Add spring.graphql.websocket.keep-alive property

As of spring-projects/spring-graphql#534, Spring for GraphQL supports
the configuration of keep-alive PINGs for WebSocket connections.
This commit auto-configures this value in the `GraphQlWebSocketHandler`
WebFlux and MVC implementations if the
`spring.graphql.websocket.keep-alive` property is configured.

Closes gh-40320

spring-boot-project/spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/graphql/GraphQlProperties.java

@@ -217,6 +217,11 @@ public class GraphQlProperties {
 		 */
 		private Duration connectionInitTimeout = Duration.ofSeconds(60);
 
+		/**
+		 * Maximum idle period before a server keep-alive ping is sent to client.
+		 */
+		private Duration keepAlive = null;
+
 		public String getPath() {
 			return this.path;
 		}
@@ -233,6 +238,14 @@ public class GraphQlProperties {
 			this.connectionInitTimeout = connectionInitTimeout;
 		}
 
+		public Duration getKeepAlive() {
+			return this.keepAlive;
+		}
+
+		public void setKeepAlive(Duration keepAlive) {
+			this.keepAlive = keepAlive;
+		}
+
 	}
 
 	public static class Rsocket {

spring-boot-project/spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/graphql/reactive/GraphQlWebFluxAutoConfiguration.java

@@ -163,7 +163,7 @@ public class GraphQlWebFluxAutoConfiguration {
 		public GraphQlWebSocketHandler graphQlWebSocketHandler(WebGraphQlHandler webGraphQlHandler,
 				GraphQlProperties properties, ServerCodecConfigurer configurer) {
 			return new GraphQlWebSocketHandler(webGraphQlHandler, configurer,
-					properties.getWebsocket().getConnectionInitTimeout());
+					properties.getWebsocket().getConnectionInitTimeout(), properties.getWebsocket().getKeepAlive());
 		}
 
 		@Bean

spring-boot-project/spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/graphql/servlet/GraphQlWebMvcAutoConfiguration.java

@@ -169,7 +169,7 @@ public class GraphQlWebMvcAutoConfiguration {
 		public GraphQlWebSocketHandler graphQlWebSocketHandler(WebGraphQlHandler webGraphQlHandler,
 				GraphQlProperties properties, HttpMessageConverters converters) {
 			return new GraphQlWebSocketHandler(webGraphQlHandler, getJsonConverter(converters),
-					properties.getWebsocket().getConnectionInitTimeout());
+					properties.getWebsocket().getConnectionInitTimeout(), properties.getWebsocket().getKeepAlive());
 		}
 
 		private GenericHttpMessageConverter<Object> getJsonConverter(HttpMessageConverters converters) {

spring-boot-project/spring-boot-autoconfigure/src/test/java/org/springframework/boot/autoconfigure/graphql/reactive/GraphQlWebFluxAutoConfigurationTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2023 the original author or authors.
+ * Copyright 2012-2024 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.
@@ -16,6 +16,7 @@
 
 package org.springframework.boot.autoconfigure.graphql.reactive;
 
+import java.time.Duration;
 import java.util.Collections;
 import java.util.Map;
 import java.util.function.Consumer;
@@ -220,6 +221,20 @@ class GraphQlWebFluxAutoConfigurationTests {
 			.run((context) -> assertThat(context).hasSingleBean(GraphQlWebSocketHandler.class));
 	}
 
+	@Test
+	void shouldConfigureWebSocketProperties() {
+		this.contextRunner
+			.withPropertyValues("spring.graphql.websocket.path=/ws",
+					"spring.graphql.websocket.connection-init-timeout=120s", "spring.graphql.websocket.keep-alive=30s")
+			.run((context) -> {
+				assertThat(context).hasSingleBean(GraphQlWebSocketHandler.class);
+				GraphQlWebSocketHandler graphQlWebSocketHandler = context.getBean(GraphQlWebSocketHandler.class);
+				assertThat(graphQlWebSocketHandler).extracting("initTimeoutDuration")
+					.isEqualTo(Duration.ofSeconds(120));
+				assertThat(graphQlWebSocketHandler).extracting("keepAliveDuration").isEqualTo(Duration.ofSeconds(30));
+			});
+	}
+
 	@Test
 	void routerFunctionShouldHaveOrderZero() {
 		this.contextRunner.withUserConfiguration(CustomRouterFunctions.class).run((context) -> {

spring-boot-project/spring-boot-autoconfigure/src/test/java/org/springframework/boot/autoconfigure/graphql/servlet/GraphQlWebMvcAutoConfigurationTests.java

@@ -16,6 +16,7 @@
 
 package org.springframework.boot.autoconfigure.graphql.servlet;
 
+import java.time.Duration;
 import java.util.Map;
 
 import graphql.schema.idl.TypeRuntimeWiring;
@@ -184,6 +185,20 @@ class GraphQlWebMvcAutoConfigurationTests {
 		});
 	}
 
+	@Test
+	void shouldConfigureWebSocketProperties() {
+		this.contextRunner
+			.withPropertyValues("spring.graphql.websocket.path=/ws",
+					"spring.graphql.websocket.connection-init-timeout=120s", "spring.graphql.websocket.keep-alive=30s")
+			.run((context) -> {
+				assertThat(context).hasSingleBean(GraphQlWebSocketHandler.class);
+				GraphQlWebSocketHandler graphQlWebSocketHandler = context.getBean(GraphQlWebSocketHandler.class);
+				assertThat(graphQlWebSocketHandler).extracting("initTimeoutDuration")
+					.isEqualTo(Duration.ofSeconds(120));
+				assertThat(graphQlWebSocketHandler).extracting("keepAliveDuration").isEqualTo(Duration.ofSeconds(30));
+			});
+	}
+
 	@Test
 	void routerFunctionShouldHaveOrderZero() {
 		this.contextRunner.withUserConfiguration(CustomRouterFunctions.class).run((context) -> {