Add configuration for Tomcat's cachingAllowed property

See gh-13614

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

@@ -52,6 +52,7 @@ import org.springframework.util.StringUtils;
  * @author Aurélien Leboulanger
  * @author Brian Clozel
  * @author Olivier Lamy
+ * @author Rob Tompkins
  */
 @ConfigurationProperties(prefix = "server", ignoreUnknownFields = true)
 public class ServerProperties {
@@ -265,6 +266,11 @@ public class ServerProperties {
 		 */
 		private final Accesslog accesslog = new Accesslog();
 
+		/**
+		 * Web resource configuration.
+		 */
+		private final WebResource webResource = new WebResource();
+
 		/**
 		 * Regular expression matching trusted IP addresses.
 		 */
@@ -399,6 +405,10 @@ public class ServerProperties {
 			return this.accesslog;
 		}
 
+		public WebResource getWebResource() {
+			return this.webResource;
+		}
+
 		public Duration getBackgroundProcessorDelay() {
 			return this.backgroundProcessorDelay;
 		}
@@ -515,6 +525,26 @@ public class ServerProperties {
 			return this.resource;
 		}
 
+		/**
+		 * Tomcat web resource properties.
+		 */
+		public static class WebResource {
+
+			/**
+			 * Whether tomcat WebResource caching is permitted for this web application.
+			 */
+			private Boolean useCaching = Boolean.TRUE;
+
+			public Boolean getUseCaching() {
+				return this.useCaching;
+			}
+
+			public void setUseCaching(Boolean useCaching) {
+				this.useCaching = useCaching;
+			}
+
+		}
+
 		/**
 		 * Tomcat access log properties.
 		 */

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

@@ -19,9 +19,11 @@ package org.springframework.boot.autoconfigure.web.embedded;
 import java.time.Duration;
 
 import org.apache.catalina.Lifecycle;
+import org.apache.catalina.WebResourceRoot;
 import org.apache.catalina.valves.AccessLogValve;
 import org.apache.catalina.valves.ErrorReportValve;
 import org.apache.catalina.valves.RemoteIpValve;
+import org.apache.catalina.webresources.StandardRoot;
 import org.apache.coyote.AbstractProtocol;
 import org.apache.coyote.ProtocolHandler;
 import org.apache.coyote.http11.AbstractHttp11Protocol;
@@ -46,6 +48,7 @@ import org.springframework.util.StringUtils;
  * @author Yulin Qin
  * @author Stephane Nicoll
  * @author Phillip Webb
+ * @author Rob Tompkins
  * @since 2.0.0
  */
 public class TomcatWebServerFactoryCustomizer implements
@@ -70,6 +73,8 @@ public class TomcatWebServerFactoryCustomizer implements
 	public void customize(ConfigurableTomcatWebServerFactory factory) {
 		ServerProperties properties = this.serverProperties;
 		ServerProperties.Tomcat tomcatProperties = properties.getTomcat();
+		ServerProperties.Tomcat.WebResource tomcatWebResourceProperties = tomcatProperties
+				.getWebResource();
 		PropertyMapper propertyMapper = PropertyMapper.get();
 		propertyMapper.from(tomcatProperties::getBasedir).whenNonNull()
 				.to(factory::setBaseDirectory);
@@ -101,6 +106,9 @@ public class TomcatWebServerFactoryCustomizer implements
 				.to((maxConnections) -> customizeMaxConnections(factory, maxConnections));
 		propertyMapper.from(tomcatProperties::getAcceptCount).when(this::isPositive)
 				.to((acceptCount) -> customizeAcceptCount(factory, acceptCount));
+		propertyMapper.from(tomcatWebResourceProperties::getUseCaching).whenFalse()
+				.to((isWebResourceCachingAllowed) -> customizeWebResourceCaching(factory,
+						isWebResourceCachingAllowed));
 		customizeStaticResources(factory);
 		customizeErrorReportValve(properties.getError(), factory);
 	}
@@ -126,6 +134,18 @@ public class TomcatWebServerFactoryCustomizer implements
 		});
 	}
 
+	private void customizeWebResourceCaching(ConfigurableTomcatWebServerFactory factory,
+			Boolean useWebResourceCaching) {
+		factory.addContextCustomizers((context) -> {
+			WebResourceRoot webResourceRoot = context.getResources();
+			if (webResourceRoot == null) {
+				webResourceRoot = new StandardRoot(context);
+			}
+			webResourceRoot.setCachingAllowed(useWebResourceCaching);
+			context.setResources(webResourceRoot);
+		});
+	}
+
 	private void customizeMaxConnections(ConfigurableTomcatWebServerFactory factory,
 			int maxConnections) {
 		factory.addConnectorCustomizers((connector) -> {

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

@@ -16,14 +16,17 @@
 
 package org.springframework.boot.autoconfigure.web.embedded;
 
+import java.util.Map;
 import java.util.function.Consumer;
 
 import org.apache.catalina.Context;
 import org.apache.catalina.Valve;
+import org.apache.catalina.mapper.Mapper;
 import org.apache.catalina.startup.Tomcat;
 import org.apache.catalina.valves.AccessLogValve;
 import org.apache.catalina.valves.ErrorReportValve;
 import org.apache.catalina.valves.RemoteIpValve;
+import org.apache.catalina.webresources.StandardRoot;
 import org.apache.coyote.AbstractProtocol;
 import org.junit.Before;
 import org.junit.Test;
@@ -36,6 +39,7 @@ import org.springframework.boot.web.embedded.tomcat.TomcatServletWebServerFactor
 import org.springframework.boot.web.embedded.tomcat.TomcatWebServer;
 import org.springframework.mock.env.MockEnvironment;
 import org.springframework.test.context.support.TestPropertySourceUtils;
+import org.springframework.test.util.ReflectionTestUtils;
 
 import static org.assertj.core.api.Assertions.assertThat;
 
@@ -44,6 +48,7 @@ import static org.assertj.core.api.Assertions.assertThat;
  *
  * @author Brian Clozel
  * @author Phillip Webb
+ * @author Rob Tompkins
  */
 public class TomcatWebServerFactoryCustomizerTests {
 
@@ -94,6 +99,20 @@ public class TomcatWebServerFactoryCustomizerTests {
 						.isEqualTo(5));
 	}
 
+	@Test
+	public void turnOffWebResourceCaching() {
+		bind("server.tomcat.webresource.use-caching=false");
+		customizeAndRunServer((server) -> {
+			Mapper mapper = server.getTomcat().getService().getMapper();
+			Object contextObjectToContextVersionMap = ReflectionTestUtils.getField(mapper,
+					"contextObjectToContextVersionMap");
+			Object tomcatEmbeddedContext = ((Map<Context, Object>) contextObjectToContextVersionMap)
+					.values().toArray()[0];
+			assertThat(((StandardRoot) ReflectionTestUtils.getField(tomcatEmbeddedContext,
+					"resources")).isCachingAllowed()).isFalse();
+		});
+	}
+
 	@Test
 	public void customMaxHttpPostSize() {
 		bind("server.tomcat.max-http-post-size=10000");

spring-boot-project/spring-boot-docs/src/main/asciidoc/appendix-application-properties.adoc

@@ -262,6 +262,7 @@ content into your application. Rather, pick only the properties that you need.
 	server.tomcat.resource.cache-ttl= # Time-to-live of the static resource cache.
 	server.tomcat.uri-encoding=UTF-8 # Character encoding to use to decode the URI.
 	server.tomcat.use-relative-redirects= # Whether HTTP 1.1 and later location headers generated by a call to sendRedirect will use relative or absolute redirects.
+	server.tomcat.webresource.use-caching= # Whether tomcat WebResource caching is permitted for this web application.
 	server.undertow.accesslog.dir= # Undertow access log directory.
 	server.undertow.accesslog.enabled=false # Whether to enable the access log.
 	server.undertow.accesslog.pattern=common # Format pattern for access logs.