diff --git a/spring-webflux/src/main/java/org/springframework/web/reactive/socket/server/upgrade/JettyRequestUpgradeStrategy.java b/spring-webflux/src/main/java/org/springframework/web/reactive/socket/server/upgrade/JettyRequestUpgradeStrategy.java
index 92b6ba4335..f688756b22 100644
--- a/spring-webflux/src/main/java/org/springframework/web/reactive/socket/server/upgrade/JettyRequestUpgradeStrategy.java
+++ b/spring-webflux/src/main/java/org/springframework/web/reactive/socket/server/upgrade/JettyRequestUpgradeStrategy.java
@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2018 the original author or authors.
+ * Copyright 2002-2019 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.
@@ -18,6 +18,7 @@ package org.springframework.web.reactive.socket.server.upgrade;
 
 import java.io.IOException;
 import java.util.function.Supplier;
+
 import javax.servlet.ServletContext;
 import javax.servlet.http.HttpServletRequest;
 import javax.servlet.http.HttpServletResponse;
@@ -32,7 +33,9 @@ import org.springframework.core.io.buffer.DataBufferFactory;
 import org.springframework.http.server.reactive.AbstractServerHttpRequest;
 import org.springframework.http.server.reactive.AbstractServerHttpResponse;
 import org.springframework.http.server.reactive.ServerHttpRequest;
+import org.springframework.http.server.reactive.ServerHttpRequestDecorator;
 import org.springframework.http.server.reactive.ServerHttpResponse;
+import org.springframework.http.server.reactive.ServerHttpResponseDecorator;
 import org.springframework.lang.Nullable;
 import org.springframework.util.Assert;
 import org.springframework.web.reactive.socket.HandshakeInfo;
@@ -144,8 +147,8 @@ public class JettyRequestUpgradeStrategy implements RequestUpgradeStrategy, Life
 		ServerHttpRequest request = exchange.getRequest();
 		ServerHttpResponse response = exchange.getResponse();
 
-		HttpServletRequest servletRequest = getHttpServletRequest(request);
-		HttpServletResponse servletResponse = getHttpServletResponse(response);
+		HttpServletRequest servletRequest = getNativeRequest(request);
+		HttpServletResponse servletResponse = getNativeResponse(response);
 
 		HandshakeInfo handshakeInfo = handshakeInfoFactory.get();
 		DataBufferFactory factory = response.bufferFactory();
@@ -173,14 +176,30 @@ public class JettyRequestUpgradeStrategy implements RequestUpgradeStrategy, Life
 		return Mono.empty();
 	}
 
-	private HttpServletRequest getHttpServletRequest(ServerHttpRequest request) {
-		Assert.isInstanceOf(AbstractServerHttpRequest.class, request);
-		return ((AbstractServerHttpRequest) request).getNativeRequest();
+	private static HttpServletRequest getNativeRequest(ServerHttpRequest request) {
+		if (request instanceof AbstractServerHttpRequest) {
+			return ((AbstractServerHttpRequest) request).getNativeRequest();
+		}
+		else if (request instanceof ServerHttpRequestDecorator) {
+			return getNativeRequest(((ServerHttpRequestDecorator) request).getDelegate());
+		}
+		else {
+			throw new IllegalArgumentException(
+					"Couldn't find HttpServletRequest in " + request.getClass().getName());
+		}
 	}
 
-	private HttpServletResponse getHttpServletResponse(ServerHttpResponse response) {
-		Assert.isInstanceOf(AbstractServerHttpResponse.class, response);
-		return ((AbstractServerHttpResponse) response).getNativeResponse();
+	private static HttpServletResponse getNativeResponse(ServerHttpResponse response) {
+		if (response instanceof AbstractServerHttpResponse) {
+			return ((AbstractServerHttpResponse) response).getNativeResponse();
+		}
+		else if (response instanceof ServerHttpResponseDecorator) {
+			return getNativeResponse(((ServerHttpResponseDecorator) response).getDelegate());
+		}
+		else {
+			throw new IllegalArgumentException(
+					"Couldn't find HttpServletResponse in " + response.getClass().getName());
+		}
 	}
 
 	private void startLazily(HttpServletRequest request) {
diff --git a/spring-webflux/src/main/java/org/springframework/web/reactive/socket/server/upgrade/ReactorNettyRequestUpgradeStrategy.java b/spring-webflux/src/main/java/org/springframework/web/reactive/socket/server/upgrade/ReactorNettyRequestUpgradeStrategy.java
index ddc2da441d..4112bc790a 100644
--- a/spring-webflux/src/main/java/org/springframework/web/reactive/socket/server/upgrade/ReactorNettyRequestUpgradeStrategy.java
+++ b/spring-webflux/src/main/java/org/springframework/web/reactive/socket/server/upgrade/ReactorNettyRequestUpgradeStrategy.java
@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2018 the original author or authors.
+ * Copyright 2002-2019 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.
@@ -24,6 +24,7 @@ import reactor.netty.http.server.HttpServerResponse;
 import org.springframework.core.io.buffer.NettyDataBufferFactory;
 import org.springframework.http.server.reactive.AbstractServerHttpResponse;
 import org.springframework.http.server.reactive.ServerHttpResponse;
+import org.springframework.http.server.reactive.ServerHttpResponseDecorator;
 import org.springframework.lang.Nullable;
 import org.springframework.web.reactive.socket.HandshakeInfo;
 import org.springframework.web.reactive.socket.WebSocketHandler;
@@ -72,7 +73,7 @@ public class ReactorNettyRequestUpgradeStrategy implements RequestUpgradeStrateg
 			@Nullable String subProtocol, Supplier<HandshakeInfo> handshakeInfoFactory) {
 
 		ServerHttpResponse response = exchange.getResponse();
-		HttpServerResponse reactorResponse = ((AbstractServerHttpResponse) response).getNativeResponse();
+		HttpServerResponse reactorResponse = getNativeResponse(response);
 		HandshakeInfo handshakeInfo = handshakeInfoFactory.get();
 		NettyDataBufferFactory bufferFactory = (NettyDataBufferFactory) response.bufferFactory();
 
@@ -85,4 +86,17 @@ public class ReactorNettyRequestUpgradeStrategy implements RequestUpgradeStrateg
 				});
 	}
 
+	private static HttpServerResponse getNativeResponse(ServerHttpResponse response) {
+		if (response instanceof AbstractServerHttpResponse) {
+			return ((AbstractServerHttpResponse) response).getNativeResponse();
+		}
+		else if (response instanceof ServerHttpResponseDecorator) {
+			return getNativeResponse(((ServerHttpResponseDecorator) response).getDelegate());
+		}
+		else {
+			throw new IllegalArgumentException(
+					"Couldn't find native response in " + response.getClass().getName());
+		}
+	}
+
 }
diff --git a/spring-webflux/src/main/java/org/springframework/web/reactive/socket/server/upgrade/TomcatRequestUpgradeStrategy.java b/spring-webflux/src/main/java/org/springframework/web/reactive/socket/server/upgrade/TomcatRequestUpgradeStrategy.java
index c308fe221c..fb4ef36dd0 100644
--- a/spring-webflux/src/main/java/org/springframework/web/reactive/socket/server/upgrade/TomcatRequestUpgradeStrategy.java
+++ b/spring-webflux/src/main/java/org/springframework/web/reactive/socket/server/upgrade/TomcatRequestUpgradeStrategy.java
@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2018 the original author or authors.
+ * Copyright 2002-2019 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.
@@ -19,6 +19,7 @@ package org.springframework.web.reactive.socket.server.upgrade;
 import java.io.IOException;
 import java.util.Collections;
 import java.util.function.Supplier;
+
 import javax.servlet.ServletException;
 import javax.servlet.http.HttpServletRequest;
 import javax.servlet.http.HttpServletResponse;
@@ -32,7 +33,9 @@ import org.springframework.core.io.buffer.DataBufferFactory;
 import org.springframework.http.server.reactive.AbstractServerHttpRequest;
 import org.springframework.http.server.reactive.AbstractServerHttpResponse;
 import org.springframework.http.server.reactive.ServerHttpRequest;
+import org.springframework.http.server.reactive.ServerHttpRequestDecorator;
 import org.springframework.http.server.reactive.ServerHttpResponse;
+import org.springframework.http.server.reactive.ServerHttpResponseDecorator;
 import org.springframework.lang.Nullable;
 import org.springframework.util.Assert;
 import org.springframework.web.reactive.socket.HandshakeInfo;
@@ -130,8 +133,8 @@ public class TomcatRequestUpgradeStrategy implements RequestUpgradeStrategy {
 		ServerHttpRequest request = exchange.getRequest();
 		ServerHttpResponse response = exchange.getResponse();
 
-		HttpServletRequest servletRequest = getHttpServletRequest(request);
-		HttpServletResponse servletResponse = getHttpServletResponse(response);
+		HttpServletRequest servletRequest = getNativeRequest(request);
+		HttpServletResponse servletResponse = getNativeResponse(response);
 
 		HandshakeInfo handshakeInfo = handshakeInfoFactory.get();
 		DataBufferFactory bufferFactory = response.bufferFactory();
@@ -155,14 +158,30 @@ public class TomcatRequestUpgradeStrategy implements RequestUpgradeStrategy {
 		return Mono.empty();
 	}
 
-	private HttpServletRequest getHttpServletRequest(ServerHttpRequest request) {
-		Assert.isInstanceOf(AbstractServerHttpRequest.class, request, "ServletServerHttpRequest required");
-		return ((AbstractServerHttpRequest) request).getNativeRequest();
+	private static HttpServletRequest getNativeRequest(ServerHttpRequest request) {
+		if (request instanceof AbstractServerHttpRequest) {
+			return ((AbstractServerHttpRequest) request).getNativeRequest();
+		}
+		else if (request instanceof ServerHttpRequestDecorator) {
+			return getNativeRequest(((ServerHttpRequestDecorator) request).getDelegate());
+		}
+		else {
+			throw new IllegalArgumentException(
+					"Couldn't find HttpServletRequest in " + request.getClass().getName());
+		}
 	}
 
-	private HttpServletResponse getHttpServletResponse(ServerHttpResponse response) {
-		Assert.isInstanceOf(AbstractServerHttpResponse.class, response, "ServletServerHttpResponse required");
-		return ((AbstractServerHttpResponse) response).getNativeResponse();
+	private static HttpServletResponse getNativeResponse(ServerHttpResponse response) {
+		if (response instanceof AbstractServerHttpResponse) {
+			return ((AbstractServerHttpResponse) response).getNativeResponse();
+		}
+		else if (response instanceof ServerHttpResponseDecorator) {
+			return getNativeResponse(((ServerHttpResponseDecorator) response).getDelegate());
+		}
+		else {
+			throw new IllegalArgumentException(
+					"Couldn't find HttpServletResponse in " + response.getClass().getName());
+		}
 	}
 
 	private WsServerContainer getContainer(HttpServletRequest request) {
diff --git a/spring-webflux/src/main/java/org/springframework/web/reactive/socket/server/upgrade/UndertowRequestUpgradeStrategy.java b/spring-webflux/src/main/java/org/springframework/web/reactive/socket/server/upgrade/UndertowRequestUpgradeStrategy.java
index 5a322bbc06..56b69515a4 100644
--- a/spring-webflux/src/main/java/org/springframework/web/reactive/socket/server/upgrade/UndertowRequestUpgradeStrategy.java
+++ b/spring-webflux/src/main/java/org/springframework/web/reactive/socket/server/upgrade/UndertowRequestUpgradeStrategy.java
@@ -33,6 +33,7 @@ import reactor.core.publisher.Mono;
 import org.springframework.core.io.buffer.DataBufferFactory;
 import org.springframework.http.server.reactive.AbstractServerHttpRequest;
 import org.springframework.http.server.reactive.ServerHttpRequest;
+import org.springframework.http.server.reactive.ServerHttpRequestDecorator;
 import org.springframework.lang.Nullable;
 import org.springframework.util.Assert;
 import org.springframework.web.reactive.socket.HandshakeInfo;
@@ -55,9 +56,7 @@ public class UndertowRequestUpgradeStrategy implements RequestUpgradeStrategy {
 	public Mono<Void> upgrade(ServerWebExchange exchange, WebSocketHandler handler,
 			@Nullable String subProtocol, Supplier<HandshakeInfo> handshakeInfoFactory) {
 
-		ServerHttpRequest request = exchange.getRequest();
-		Assert.isInstanceOf(AbstractServerHttpRequest.class, request);
-		HttpServerExchange httpExchange = ((AbstractServerHttpRequest) request).getNativeRequest();
+		HttpServerExchange httpExchange = getNativeRequest(exchange.getRequest());
 
 		Set<String> protocols = (subProtocol != null ? Collections.singleton(subProtocol) : Collections.emptySet());
 		Hybi13Handshake handshake = new Hybi13Handshake(protocols, false);
@@ -77,6 +76,19 @@ public class UndertowRequestUpgradeStrategy implements RequestUpgradeStrategy {
 		return Mono.empty();
 	}
 
+	private static HttpServerExchange getNativeRequest(ServerHttpRequest request) {
+		if (request instanceof AbstractServerHttpRequest) {
+			return ((AbstractServerHttpRequest) request).getNativeRequest();
+		}
+		else if (request instanceof ServerHttpRequestDecorator) {
+			return getNativeRequest(((ServerHttpRequestDecorator) request).getDelegate());
+		}
+		else {
+			throw new IllegalArgumentException(
+					"Couldn't find HttpServerExchange in " + request.getClass().getName());
+		}
+	}
+
 
 	private class DefaultCallback implements WebSocketConnectionCallback {