Do not reuse WebsocketServerSpec.Builder between requests

Fixes gh-2159
Fixes gh-2160

spring-cloud-gateway-server/src/main/java/org/springframework/cloud/gateway/config/GatewayAutoConfiguration.java

@@ -19,6 +19,7 @@
 import java.security.cert.X509Certificate;
 import java.util.List;
 import java.util.Set;
+import java.util.function.Supplier;
 
 import com.netflix.hystrix.HystrixObservableCommand;
 import io.netty.channel.ChannelOption;
@@ -28,6 +29,7 @@
 import org.apache.commons.logging.LogFactory;
 import reactor.core.publisher.Flux;
 import reactor.netty.http.client.HttpClient;
+import reactor.netty.http.server.WebsocketServerSpec;
 import reactor.netty.resources.ConnectionProvider;
 import reactor.netty.tcp.ProxyProvider;
 import rx.RxReactiveStreams;
@@ -812,17 +814,17 @@ public ReactorNettyWebSocketClient reactorNettyWebSocketClient(
 		@Bean
 		public ReactorNettyRequestUpgradeStrategy reactorNettyRequestUpgradeStrategy(
 				HttpClientProperties httpClientProperties) {
-			ReactorNettyRequestUpgradeStrategy requestUpgradeStrategy = new ReactorNettyRequestUpgradeStrategy();
-
-			HttpClientProperties.Websocket websocket = httpClientProperties
-					.getWebsocket();
-			PropertyMapper map = PropertyMapper.get();
-			map.from(websocket::getMaxFramePayloadLength).whenNonNull()
-					.to(requestUpgradeStrategy::setMaxFramePayloadLength);
-			map.from(websocket::isProxyPing).to(requestUpgradeStrategy::setHandlePing);
-			return requestUpgradeStrategy;
-		}
 
+			Supplier<WebsocketServerSpec.Builder> builderSupplier = () -> {
+				WebsocketServerSpec.Builder builder = WebsocketServerSpec.builder();
+				HttpClientProperties.Websocket websocket = httpClientProperties.getWebsocket();
+				PropertyMapper map = PropertyMapper.get();
+				map.from(websocket::getMaxFramePayloadLength).whenNonNull().to(builder::maxFramePayloadLength);
+				map.from(websocket::isProxyPing).to(builder::handlePing);
+				return builder;
+			};
+
+			return new ReactorNettyRequestUpgradeStrategy(builderSupplier);
 	}
 
 	@Configuration(proxyBeanMethods = false)

spring-cloud-gateway-server/src/test/java/org/springframework/cloud/gateway/config/GatewayAutoConfigurationTests.java

@@ -16,10 +16,13 @@
 
 package org.springframework.cloud.gateway.config;
 
+import java.lang.reflect.InvocationTargetException;
+import java.lang.reflect.Method;
 import java.util.concurrent.atomic.AtomicBoolean;
 
 import org.junit.Test;
 import reactor.netty.http.client.HttpClient;
+import reactor.netty.http.server.WebsocketServerSpec;
 
 import org.springframework.boot.SpringApplication;
 import org.springframework.boot.SpringBootConfiguration;
@@ -160,6 +163,22 @@ public void verboseActuatorDisabled() {
 		}
 	}
 
+	@Test // gh-2159
+	public void reactorNettyRequestUpgradeStrategyWebSocketSpecBuilderIsUniquePerRequest()
+			throws NoSuchMethodException, InvocationTargetException, IllegalAccessException {
+		ReactorNettyRequestUpgradeStrategy strategy = new GatewayAutoConfiguration.NettyConfiguration()
+				.reactorNettyRequestUpgradeStrategy(new HttpClientProperties());
+
+		// Method "buildSpec" was introduced for Tests, but has only default visiblity
+		Method buildSpec = ReactorNettyRequestUpgradeStrategy.class.getDeclaredMethod("buildSpec", String.class);
+		buildSpec.setAccessible(true);
+		WebsocketServerSpec spec1 = (WebsocketServerSpec) buildSpec.invoke(strategy, "p1");
+		WebsocketServerSpec spec2 = strategy.getWebsocketServerSpec();
+
+		assertThat(spec1.protocols()).isEqualTo("p1");
+		assertThat(spec2.protocols()).isNull();
+	}
+
 	@EnableAutoConfiguration
 	@SpringBootConfiguration
 	protected static class Config {