Support a handler for checking connection status using Ping frame in HTTP/2

docs/modules/ROOT/pages/http-client.adoc

@@ -680,6 +680,50 @@ include::{examples-dir}/channeloptions/Application.java[lines=18..54]
 <4> Configures the time between individual `keepalive` probes to 1 minute.
 <5> Configures the maximum number of TCP `keepalive` probes to 8.
 
+
+==== IdleTimeout
+The maximum time (resolution: ms) that this connection stays opened and waits for HTTP request. Once the timeout is reached, the connection is closed.
+By default, `idleTimeout` is not specified, this indicates no timeout (i.e. infinite), which means the connection is closed only if one of the peers decides to close it explicitly.
+
+NOTE: It is always a good practice to configure an idle timeout.
+
+To customize the default settings, you can configure `HttpClient` as follows:
+
+{examples-link}/idle/timeout/Application.java
+----
+include::{examples-dir}/idle/timeout/Application.java[lines=26..44]
+----
+<1> Configures the default idle timeout to 1 second.
+
+===== Configuring Ping Frame for HTTP/2 Health Check
+When using the HTTP/2 protocol, it is recommended to configure a *PING* frame to maintain the connection and ensure timely health checks.
+The HttpClient in Reactor Netty allows setting up a  *PING* frame to prevent idle connections from being prematurely closed when *idleTimeout* is configured.
+
+[NOTE]
+====
+To enable HTTP/2 PING frame-based health checks, you must configure `idleTimeout`.
+Without `idleTimeout`, the connection may remain open indefinitely, preventing proper detection of inactive or unresponsive connections.
+Setting an appropriate `idleTimeout` ensures that PING-based health checks can effectively terminate unresponsive connections.
+====
+
+*Benefits of Using PING Frames*
+
+- Actively monitors connection health by checking real-time responses to *PING* frames.
+- Ensures that health checks detect unresponsive connections quickly.
+- Helps maintain long-lived connections in an efficient manner.
+
+To enable *PING* frames for HTTP/2 connections, configure the HttpClient as follows:
+
+{examples-link}/liveness/Application.java
+----
+include::{examples-dir}/liveness/Application.java[lines=26..49]
+----
+<1> To set up a health check using HTTP2 Ping frame, `idleTimeout` must be set first.
+<2> Sets the interval for sending `HTTP/2` `PING` frames and receiving `ACK` responses
+<3> Sets the execution interval for the scheduler that sends `HTTP/2` `PING frames and periodically checks for `ACK` responses
+<4> Sets the threshold for retrying `HTTP/2` `PING` frame transmissions.
+
+
 [[ssl-tls-timeout]]
 ==== SSL/TLS Timeout
 `HttpClient` supports the SSL/TLS functionality provided by Netty.

docs/modules/ROOT/pages/http-server.adoc

@@ -726,6 +726,35 @@ include::{examples-dir}/idle/timeout/Application.java[lines=18..35]
 ----
 <1> Configures the default idle timeout to 1 second.
 
+==== Configuring Ping Frame for HTTP/2 Health Check
+When using the HTTP/2 protocol, it is recommended to configure a *PING* frame to maintain the connection and ensure timely health checks.
+The HttpServer in Reactor Netty allows setting up a  *PING* frame to prevent idle connections from being prematurely closed when *idleTimeout* is configured.
+
+[NOTE]
+====
+To enable HTTP/2 PING frame-based health checks, you must configure `idleTimeout`.
+Without `idleTimeout`, the connection may remain open indefinitely, preventing proper detection of inactive or unresponsive connections.
+Setting an appropriate `idleTimeout` ensures that PING-based health checks can effectively terminate unresponsive connections.
+====
+
+*Benefits of Using PING Frames*
+
+- Actively monitors connection health by checking real-time responses to *PING* frames.
+- Ensures that health checks detect unresponsive connections quickly.
+- Helps maintain long-lived connections in an efficient manner.
+
+To enable *PING* frames for HTTP/2 connections, configure the HttpServer as follows:
+
+{examples-link}/liveness/Application.java
+----
+include::{examples-dir}/liveness/Application.java[lines=26..50]
+----
+<1> To set up a health check using HTTP2 Ping frame, `idleTimeout` must be set first.
+<2> Sets the interval for sending `HTTP/2` `PING` frames and receiving `ACK` responses
+<3> Sets the execution interval for the scheduler that sends `HTTP/2` `PING frames and periodically checks for `ACK` responses
+<4> Sets the threshold for retrying `HTTP/2` `PING` frame transmissions.
+
+
 [[http-server-ssl-tls-timeout]]
 === SSL/TLS Timeout
 `HttpServer` supports the SSL/TLS functionality provided by Netty.

reactor-netty-examples/src/main/java/reactor/netty/examples/documentation/http/client/idle/timeout/Application.java

@@ -0,0 +1,44 @@
+/*
+ * Copyright (c) 2025 VMware, Inc. or its affiliates, All Rights Reserved.
+ *
+ * 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 reactor.netty.examples.documentation.http.client.idle.timeout;
+
+import io.netty.handler.codec.http.HttpHeaders;
+import reactor.core.publisher.Mono;
+import reactor.netty.http.HttpProtocol;
+import reactor.netty.http.client.HttpClient;
+import reactor.util.function.Tuple2;
+
+import java.time.Duration;
+
+public class Application {
+
+	public static void main(String[] args) {
+		HttpClient client =
+				HttpClient.create()
+						.protocol(HttpProtocol.H2)
+						.secure()
+						.idleTimeout(Duration.ofSeconds(1)); //<1>
+
+		Tuple2<String, HttpHeaders> response =
+				client.get()
+						.uri("https://example.com/")
+						.responseSingle((res, bytes) -> bytes.asString()
+								.zipWith(Mono.just(res.responseHeaders())))
+						.block();
+		System.out.println("Used stream ID: " + response.getT2().get("x-http2-stream-id"));
+		System.out.println("Response: " + response.getT1());
+	}
+}

reactor-netty-examples/src/main/java/reactor/netty/examples/documentation/http/client/liveness/Application.java

@@ -0,0 +1,49 @@
+/*
+ * Copyright (c) 2025 VMware, Inc. or its affiliates, All Rights Reserved.
+ *
+ * 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 reactor.netty.examples.documentation.http.client.liveness;
+
+import io.netty.handler.codec.http.HttpHeaders;
+import reactor.core.publisher.Mono;
+import reactor.netty.http.HttpProtocol;
+import reactor.netty.http.client.HttpClient;
+import reactor.util.function.Tuple2;
+
+import java.time.Duration;
+
+public class Application {
+
+	public static void main(String[] args) {
+		HttpClient client =
+				HttpClient.create()
+						.protocol(HttpProtocol.H2)
+						.secure()
+						.idleTimeout(Duration.ofSeconds(1)) //<1>
+						.http2Settings(
+								builder -> builder.pingAckTimeout(Duration.ofMillis(600))  // <2>
+										.pingScheduleInterval(Duration.ofMillis(300))  // <3>
+										.pingAckDropThreshold(2)  // <4>
+						);
+
+		Tuple2<String, HttpHeaders> response =
+				client.get()
+						.uri("https://example.com/")
+						.responseSingle((res, bytes) -> bytes.asString()
+								.zipWith(Mono.just(res.responseHeaders())))
+						.block();
+		System.out.println("Used stream ID: " + response.getT2().get("x-http2-stream-id"));
+		System.out.println("Response: " + response.getT1());
+	}
+}

reactor-netty-examples/src/main/java/reactor/netty/examples/documentation/http/server/liveness/Application.java

@@ -0,0 +1,50 @@
+/*
+ * Copyright (c) 2025 VMware, Inc. or its affiliates, All Rights Reserved.
+ *
+ * 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 reactor.netty.examples.documentation.http.server.liveness;
+
+import reactor.netty.DisposableServer;
+import reactor.netty.http.Http2SslContextSpec;
+import reactor.netty.http.HttpProtocol;
+import reactor.netty.http.server.HttpServer;
+
+import java.io.File;
+import java.time.Duration;
+
+public class Application {
+
+	public static void main(String[] args) {
+		File cert = new File("certificate.crt");
+		File key = new File("private.key");
+
+		Http2SslContextSpec http2SslContextSpec = Http2SslContextSpec.forServer(cert, key);
+
+		DisposableServer server =
+				HttpServer.create()
+						.port(8080)
+						.protocol(HttpProtocol.H2)
+						.secure(spec -> spec.sslContext(http2SslContextSpec))
+						.idleTimeout(Duration.ofSeconds(1)) //<1>
+						.http2Settings(
+								builder -> builder.pingAckTimeout(Duration.ofMillis(600))  // <2>
+										.pingScheduleInterval(Duration.ofMillis(300))  // <3>
+										.pingAckDropThreshold(2)  // <4>
+						)
+						.bindNow();
+
+		server.onDispose()
+				.block();
+	}
+}