Allow H1, H2, and H2C protocol for HttpClient

Enable H1, H2, and H2C protocols for HttpClient by
dropping H2C protocol when handling HTTPS urls, and by
dropping H2 protocol when handling HTTP urls
when another protocol is present

This is a backport for PR  #2659

Signed-off-by: TaiYau Chan <[email protected]>

Author: alextychan

reactor-netty-http/src/main/java/reactor/netty/http/client/HttpClientConnect.java

@@ -214,18 +214,20 @@ public void subscribe(CoreSubscriber<? super Connection> actual) {
 				if (handler.toURI.isSecure()) {
 					if (_config.sslProvider == null) {
 						_config = new HttpClientConfig(config);
-						if (_config.checkProtocol(HttpClientConfig.h2c) && _config.protocols.length > 1) {
-							removeIncompatibleProtocol(_config, HttpProtocol.H2C);
-						}
 						_config.sslProvider = HttpClientSecure.defaultSslProvider(_config);
 					}
 
 					if (_config.checkProtocol(HttpClientConfig.h2c)) {
-						sink.error(new IllegalArgumentException(
-								"Configured H2 Clear-Text protocol with TLS. " +
-										"Use the non Clear-Text H2 protocol via HttpClient#protocol or disable TLS " +
-										"via HttpClient#noSSL()"));
-						return;
+						if (_config.protocols.length > 1) {
+							removeIncompatibleProtocol(_config, HttpProtocol.H2C);
+						}
+						else {
+							sink.error(new IllegalArgumentException(
+									"Configured H2 Clear-Text protocol with TLS. " +
+											"Use the non Clear-Text H2 protocol via HttpClient#protocol or disable TLS " +
+											"via HttpClient#noSSL()"));
+							return;
+						}
 					}
 
 					if (_config.sslProvider.getDefaultConfigurationType() == null) {
@@ -242,17 +244,19 @@ public void subscribe(CoreSubscriber<? super Connection> actual) {
 				else {
 					if (_config.sslProvider != null) {
 						_config = new HttpClientConfig(config);
-						if (_config.checkProtocol(HttpClientConfig.h2) && _config.protocols.length > 1) {
-							removeIncompatibleProtocol(_config, HttpProtocol.H2);
-						}
 						_config.sslProvider = null;
 					}
 
 					if (_config.checkProtocol(HttpClientConfig.h2)) {
-						sink.error(new IllegalArgumentException(
-								"Configured H2 protocol without TLS. Use H2 Clear-Text " +
-										"protocol via HttpClient#protocol or configure TLS via HttpClient#secure"));
-						return;
+						if (_config.protocols.length > 1) {
+							removeIncompatibleProtocol(_config, HttpProtocol.H2);
+						}
+						else {
+							sink.error(new IllegalArgumentException(
+									"Configured H2 protocol without TLS. Use H2 Clear-Text " +
+											"protocol via HttpClient#protocol or configure TLS via HttpClient#secure"));
+							return;
+						}
 					}
 				}
 

reactor-netty-http/src/test/java/reactor/netty/http/Http2Tests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2020-2022 VMware, Inc. or its affiliates, All Rights Reserved.
+ * Copyright (c) 2020-2023 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.
@@ -580,4 +580,49 @@ private void testTooManyPermitsReturned(HttpClient client) {
 	void testIssue1789() throws Exception {
 		doTestMaxActiveStreams(HttpClient.create(), 1, 1, 1, 2, 0);
 	}
+
+	@Test
+	void testPR2659_SchemeHttpConfiguredNoSsl() {
+		doTestPR2659_SchemeHttp("1");
+	}
+
+	private void doTestPR2659_SchemeHttp(String expectedStreamId) {
+		disposableServer =
+				createServer()
+						.host("localhost")
+						.protocol(HttpProtocol.HTTP11, HttpProtocol.H2C)
+						.handle((req, res) -> res.sendString(Mono.just("testPR2659")))
+						.bindNow(Duration.ofSeconds(30));
+
+		HttpClient.create()
+				.protocol(HttpProtocol.HTTP11, HttpProtocol.H2, HttpProtocol.H2C)
+				.wiretap(true)
+				.get()
+				.uri("http://localhost:" + disposableServer.port() + "/")
+				.responseSingle((res, bytes) -> Mono.just(res.responseHeaders().get("x-http2-stream-id", "null")))
+				.as(StepVerifier::create)
+				.expectNext(expectedStreamId)
+				.expectComplete()
+				.verify(Duration.ofSeconds(30));
+	}
+
+	@Test
+	void testPR2659_SchemeHttpsConfiguredWithSsl() {
+		doTestPR2659_SchemeHttps(s -> !"null".equals(s));
+	}
+
+	private void doTestPR2659_SchemeHttps(Predicate<String> predicate) {
+		HttpClient.create()
+				.protocol(HttpProtocol.HTTP11, HttpProtocol.H2, HttpProtocol.H2C)
+				.secure(sslContextSpec -> sslContextSpec.sslContext(Http2SslContextSpec.forClient()))
+				.wiretap(true)
+				.get()
+				.uri("https://example.com")
+				.responseSingle((res, bytes) -> Mono.just(res.responseHeaders().get("x-http2-stream-id", "null")))
+				.as(StepVerifier::create)
+				.expectNextMatches(predicate)
+				.expectComplete()
+				.verify(Duration.ofSeconds(30));
+	}
+
 }