Configure X-Forwarded-* support with Reactor Netty

This commit configures the new X-Forwarded-* / Forwarded HTTP headers
support with Reactor Netty in its 0.8.0 version.

Closes gh-10900

spring-boot-project/spring-boot-actuator-autoconfigure/src/main/java/org/springframework/boot/actuate/autoconfigure/web/reactive/ReactiveManagementChildContextConfiguration.java

@@ -23,6 +23,7 @@
 import org.springframework.boot.autoconfigure.condition.ConditionalOnWebApplication;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnWebApplication.Type;
 import org.springframework.boot.autoconfigure.web.embedded.JettyWebServerFactoryCustomizer;
+import org.springframework.boot.autoconfigure.web.embedded.NettyWebServerFactoryCustomizer;
 import org.springframework.boot.autoconfigure.web.embedded.TomcatWebServerFactoryCustomizer;
 import org.springframework.boot.autoconfigure.web.embedded.UndertowWebServerFactoryCustomizer;
 import org.springframework.boot.autoconfigure.web.reactive.ReactiveWebServerFactoryCustomizer;
@@ -64,7 +65,8 @@ class ReactiveManagementWebServerFactoryCustomizer extends
 			super(beanFactory, ReactiveWebServerFactoryCustomizer.class,
 					TomcatWebServerFactoryCustomizer.class,
 					JettyWebServerFactoryCustomizer.class,
-					UndertowWebServerFactoryCustomizer.class);
+					UndertowWebServerFactoryCustomizer.class,
+					NettyWebServerFactoryCustomizer.class);
 		}
 
 	}

spring-boot-project/spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/web/embedded/EmbeddedWebServerFactoryCustomizerAutoConfiguration.java

@@ -23,6 +23,7 @@
 import org.eclipse.jetty.util.Loader;
 import org.eclipse.jetty.webapp.WebAppContext;
 import org.xnio.SslClientAuthMode;
+import reactor.netty.http.server.HttpServer;
 
 import org.springframework.boot.autoconfigure.EnableAutoConfiguration;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnClass;
@@ -84,4 +85,19 @@ public UndertowWebServerFactoryCustomizer undertowWebServerFactoryCustomizer(
 
 	}
 
+	/**
+	 * Nested configuration if Netty is being used.
+	 */
+	@Configuration
+	@ConditionalOnClass(HttpServer.class)
+	public static class NettyWebServerFactoryCustomizerConfiguration {
+
+		@Bean
+		public NettyWebServerFactoryCustomizer nettyWebServerFactoryCustomizer(
+				Environment environment, ServerProperties serverProperties) {
+			return new NettyWebServerFactoryCustomizer(environment, serverProperties);
+		}
+
+	}
+
 }

spring-boot-project/spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/web/embedded/NettyWebServerFactoryCustomizer.java

@@ -0,0 +1,65 @@
+/*
+ * Copyright 2012-2018 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.
+ * You may obtain a copy of the License at
+ *
+ *      http://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 org.springframework.boot.autoconfigure.web.embedded;
+
+import org.springframework.boot.autoconfigure.web.ServerProperties;
+import org.springframework.boot.cloud.CloudPlatform;
+import org.springframework.boot.web.embedded.netty.NettyReactiveWebServerFactory;
+import org.springframework.boot.web.server.WebServerFactoryCustomizer;
+import org.springframework.core.Ordered;
+import org.springframework.core.env.Environment;
+
+/**
+ * Customization for Netty-specific features.
+ *
+ * @author Brian Clozel
+ * @since 2.1.0
+ */
+public class NettyWebServerFactoryCustomizer
+		implements WebServerFactoryCustomizer<NettyReactiveWebServerFactory>, Ordered {
+
+	private final Environment environment;
+
+	private final ServerProperties serverProperties;
+
+	public NettyWebServerFactoryCustomizer(Environment environment,
+			ServerProperties serverProperties) {
+		this.environment = environment;
+		this.serverProperties = serverProperties;
+	}
+
+	@Override
+	public int getOrder() {
+		return 0;
+	}
+
+	@Override
+	public void customize(NettyReactiveWebServerFactory factory) {
+		factory.setUseForwardHeaders(
+				getOrDeduceUseForwardHeaders(this.serverProperties, this.environment));
+	}
+
+	private boolean getOrDeduceUseForwardHeaders(ServerProperties serverProperties,
+			Environment environment) {
+		if (serverProperties.isUseForwardHeaders() != null) {
+			return serverProperties.isUseForwardHeaders();
+		}
+		CloudPlatform platform = CloudPlatform.getActive(environment);
+		return platform != null && platform.isUsingForwardHeaders();
+	}
+
+}

spring-boot-project/spring-boot-autoconfigure/src/test/java/org/springframework/boot/autoconfigure/web/embedded/NettyWebServerFactoryCustomizerTests.java

@@ -0,0 +1,75 @@
+/*
+ * Copyright 2012-2018 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.
+ * You may obtain a copy of the License at
+ *
+ *      http://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 org.springframework.boot.autoconfigure.web.embedded;
+
+import org.junit.Before;
+import org.junit.Test;
+
+import org.springframework.boot.autoconfigure.web.ServerProperties;
+import org.springframework.boot.context.properties.source.ConfigurationPropertySources;
+import org.springframework.boot.web.embedded.netty.NettyReactiveWebServerFactory;
+import org.springframework.mock.env.MockEnvironment;
+
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.verify;
+
+/**
+ * Tests for {@link NettyWebServerFactoryCustomizer}.
+ *
+ * @author Brian Clozel
+ */
+public class NettyWebServerFactoryCustomizerTests {
+
+	private MockEnvironment environment;
+
+	private ServerProperties serverProperties;
+
+	private NettyWebServerFactoryCustomizer customizer;
+
+	@Before
+	public void setup() {
+		this.environment = new MockEnvironment();
+		this.serverProperties = new ServerProperties();
+		ConfigurationPropertySources.attach(this.environment);
+		this.customizer = new NettyWebServerFactoryCustomizer(this.environment,
+				this.serverProperties);
+	}
+
+	@Test
+	public void deduceUseForwardHeadersUndertow() {
+		this.environment.setProperty("DYNO", "-");
+		NettyReactiveWebServerFactory factory = mock(NettyReactiveWebServerFactory.class);
+		this.customizer.customize(factory);
+		verify(factory).setUseForwardHeaders(true);
+	}
+
+	@Test
+	public void defaultUseForwardHeadersUndertow() {
+		NettyReactiveWebServerFactory factory = mock(NettyReactiveWebServerFactory.class);
+		this.customizer.customize(factory);
+		verify(factory).setUseForwardHeaders(false);
+	}
+
+	@Test
+	public void setUseForwardHeadersUndertow() {
+		this.serverProperties.setUseForwardHeaders(true);
+		NettyReactiveWebServerFactory factory = mock(NettyReactiveWebServerFactory.class);
+		this.customizer.customize(factory);
+		verify(factory).setUseForwardHeaders(true);
+	}
+
+}

spring-boot-project/spring-boot/src/main/java/org/springframework/boot/web/embedded/netty/NettyReactiveWebServerFactory.java

@@ -44,6 +44,8 @@ public class NettyReactiveWebServerFactory extends AbstractReactiveWebServerFact
 
 	private Duration lifecycleTimeout;
 
+	private boolean useForwardHeaders;
+
 	public NettyReactiveWebServerFactory() {
 	}
 
@@ -97,6 +99,14 @@ public void setLifecycleTimeout(Duration lifecycleTimeout) {
 		this.lifecycleTimeout = lifecycleTimeout;
 	}
 
+	/**
+	 * Set if x-forward-* headers should be processed.
+	 * @param useForwardHeaders if x-forward headers should be used
+	 */
+	public void setUseForwardHeaders(boolean useForwardHeaders) {
+		this.useForwardHeaders = useForwardHeaders;
+	}
+
 	private HttpServer createHttpServer() {
 		HttpServer server = HttpServer.create().tcpConfiguration(
 				(tcpServer) -> tcpServer.addressSupplier(() -> getListenAddress()));
@@ -110,6 +120,7 @@ private HttpServer createHttpServer() {
 					getCompression());
 			server = compressionCustomizer.apply(server);
 		}
+		server = (this.useForwardHeaders ? server.forwarded() : server.noForwarded());
 		return applyCustomizers(server);
 	}
 

spring-boot-project/spring-boot/src/test/java/org/springframework/boot/web/embedded/jetty/JettyReactiveWebServerFactoryTests.java

@@ -93,4 +93,11 @@ public void specificIPAddressNotReverseResolved() throws Exception {
 				.isEqualTo(localhost.getHostAddress());
 	}
 
+	@Test
+	public void useForwardedHeaders() {
+		JettyReactiveWebServerFactory factory = getFactory();
+		factory.setUseForwardHeaders(true);
+		assertForwardHeaderIsUsed(factory);
+	}
+
 }

spring-boot-project/spring-boot/src/test/java/org/springframework/boot/web/embedded/netty/NettyReactiveWebServerFactoryTests.java

@@ -74,4 +74,11 @@ public void nettyCustomizers() {
 		}
 	}
 
+	@Test
+	public void useForwardedHeaders() {
+		NettyReactiveWebServerFactory factory = getFactory();
+		factory.setUseForwardHeaders(true);
+		assertForwardHeaderIsUsed(factory);
+	}
+
 }

spring-boot-project/spring-boot/src/test/java/org/springframework/boot/web/embedded/tomcat/TomcatReactiveWebServerFactoryTests.java

@@ -23,6 +23,7 @@
 import org.apache.catalina.LifecycleListener;
 import org.apache.catalina.connector.Connector;
 import org.apache.catalina.core.AprLifecycleListener;
+import org.apache.catalina.valves.RemoteIpValve;
 import org.junit.Test;
 import org.mockito.ArgumentCaptor;
 import org.mockito.InOrder;
@@ -133,4 +134,13 @@ public void tomcatConnectorCustomizersShouldBeInvoked() {
 		}
 	}
 
+	@Test
+	public void useForwardedHeaders() {
+		TomcatReactiveWebServerFactory factory = getFactory();
+		RemoteIpValve valve = new RemoteIpValve();
+		valve.setProtocolHeader("X-Forwarded-Proto");
+		factory.addEngineValves(valve);
+		assertForwardHeaderIsUsed(factory);
+	}
+
 }

spring-boot-project/spring-boot/src/test/java/org/springframework/boot/web/embedded/undertow/UndertowReactiveWebServerFactoryTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2017 the original author or authors.
+ * Copyright 2012-2018 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.
@@ -76,4 +76,11 @@ public void builderCustomizersShouldBeInvoked() {
 		}
 	}
 
+	@Test
+	public void useForwardedHeaders() {
+		UndertowReactiveWebServerFactory factory = getFactory();
+		factory.setUseForwardHeaders(true);
+		assertForwardHeaderIsUsed(factory);
+	}
+
 }

spring-boot-project/spring-boot/src/test/java/org/springframework/boot/web/reactive/server/AbstractReactiveWebServerFactoryTests.java

@@ -47,6 +47,7 @@
 import org.springframework.boot.web.server.Ssl;
 import org.springframework.boot.web.server.WebServer;
 import org.springframework.core.io.buffer.DataBuffer;
+import org.springframework.core.io.buffer.DataBufferFactory;
 import org.springframework.core.io.buffer.DefaultDataBufferFactory;
 import org.springframework.http.HttpStatus;
 import org.springframework.http.MediaType;
@@ -318,6 +319,14 @@ protected void assertResponseIsNotCompressed(ResponseEntity<Void> response) {
 		assertThat(response.getHeaders().keySet()).doesNotContain("X-Test-Compressed");
 	}
 
+	protected void assertForwardHeaderIsUsed(AbstractReactiveWebServerFactory factory) {
+		this.webServer = factory.getWebServer(new XForwardedHandler());
+		this.webServer.start();
+		String body = getWebClient().build().get().header("X-Forwarded-Proto", "https")
+				.retrieve().bodyToMono(String.class).block();
+		assertThat(body).isEqualTo("https");
+	}
+
 	protected static class EchoHandler implements HttpHandler {
 
 		public EchoHandler() {
@@ -374,4 +383,17 @@ public Mono<Void> handle(ServerHttpRequest request, ServerHttpResponse response)
 
 	}
 
+	protected static class XForwardedHandler implements HttpHandler {
+
+		@Override
+		public Mono<Void> handle(ServerHttpRequest request, ServerHttpResponse response) {
+			String scheme = request.getURI().getScheme();
+			DataBufferFactory bufferFactory = new DefaultDataBufferFactory();
+			DataBuffer buffer = bufferFactory
+					.wrap(scheme.getBytes(StandardCharsets.UTF_8));
+			return response.writeWith(Mono.just(buffer));
+		}
+
+	}
+
 }