Make "MaxSwallowSize" more easily configurable

See gh-13966

Author: artsiom

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

@@ -52,6 +52,7 @@
  * @author Aurélien Leboulanger
  * @author Brian Clozel
  * @author Olivier Lamy
+ * @author Artsiom Yudovin
  */
 @ConfigurationProperties(prefix = "server", ignoreUnknownFields = true)
 public class ServerProperties {
@@ -359,6 +360,11 @@ public static class Tomcat {
 		 */
 		private int acceptCount = 0;
 
+		/**
+		 * Maximum amount of request body to swallow.
+		 */
+		private int maxSwallowSize = 0;
+
 		/**
 		 * Comma-separated list of additional patterns that match jars to ignore for TLD
 		 * scanning. The special '?' and '*' characters can be used in the pattern to
@@ -503,6 +509,14 @@ public void setAcceptCount(int acceptCount) {
 			this.acceptCount = acceptCount;
 		}
 
+		public int getMaxSwallowSize() {
+			return this.maxSwallowSize;
+		}
+
+		public void setMaxSwallowSize(int maxSwallowSize) {
+			this.maxSwallowSize = maxSwallowSize;
+		}
+
 		public List<String> getAdditionalTldSkipPatterns() {
 			return this.additionalTldSkipPatterns;
 		}

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

@@ -46,6 +46,7 @@
  * @author Yulin Qin
  * @author Stephane Nicoll
  * @author Phillip Webb
+ * @author Artsiom Yudovin
  * @since 2.0.0
  */
 public class TomcatWebServerFactoryCustomizer implements
@@ -101,6 +102,9 @@ public void customize(ConfigurableTomcatWebServerFactory factory) {
 				.to((maxConnections) -> customizeMaxConnections(factory, maxConnections));
 		propertyMapper.from(tomcatProperties::getAcceptCount).when(this::isPositive)
 				.to((acceptCount) -> customizeAcceptCount(factory, acceptCount));
+		propertyMapper.from(tomcatProperties::getMaxSwallowSize)
+				.when((maxSwallowSize) -> maxSwallowSize != 0)
+				.to((maxSwallowSize) -> customizeMaxSwallowSize(factory, maxSwallowSize));
 		customizeStaticResources(factory);
 		customizeErrorReportValve(properties.getError(), factory);
 	}
@@ -266,4 +270,16 @@ private void customizeErrorReportValve(ErrorProperties error,
 		}
 	}
 
+	@SuppressWarnings("rawtypes")
+	private void customizeMaxSwallowSize(ConfigurableTomcatWebServerFactory factory,
+			int maxSwallowSize) {
+		factory.addConnectorCustomizers((connector) -> {
+			ProtocolHandler handler = connector.getProtocolHandler();
+			if (handler instanceof AbstractHttp11Protocol) {
+				AbstractHttp11Protocol protocol = (AbstractHttp11Protocol) handler;
+				protocol.setMaxSwallowSize(maxSwallowSize);
+			}
+		});
+	}
+
 }

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

@@ -42,6 +42,7 @@
  * @author Eddú Meléndez
  * @author Quinten De Swaef
  * @author Venil Noronha
+ * @author Artsiom Yudovin
  */
 public class ServerPropertiesTests {
 
@@ -91,6 +92,7 @@ public void testTomcatBinding() {
 		map.put("server.tomcat.remote-ip-header", "Remote-Ip");
 		map.put("server.tomcat.internal-proxies", "10\\.\\d{1,3}\\.\\d{1,3}\\.\\d{1,3}");
 		map.put("server.tomcat.background-processor-delay", "10");
+		map.put("server.tomcat.max-swallow-size", "2");
 		bind(map);
 		ServerProperties.Tomcat tomcat = this.properties.getTomcat();
 		assertThat(tomcat.getAccesslog().getPattern()).isEqualTo("%h %t '%r' %s %b");
@@ -105,6 +107,7 @@ public void testTomcatBinding() {
 				.isEqualTo("10\\.\\d{1,3}\\.\\d{1,3}\\.\\d{1,3}");
 		assertThat(tomcat.getBackgroundProcessorDelay())
 				.isEqualTo(Duration.ofSeconds(10));
+		assertThat(tomcat.getMaxSwallowSize()).isEqualTo(2);
 	}
 
 	@Test

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

@@ -28,6 +28,7 @@
 import org.apache.catalina.valves.RemoteIpValve;
 import org.apache.catalina.webresources.StandardRoot;
 import org.apache.coyote.AbstractProtocol;
+import org.apache.coyote.http11.AbstractHttp11Protocol;
 import org.junit.Before;
 import org.junit.Test;
 
@@ -49,6 +50,7 @@
  * @author Brian Clozel
  * @author Phillip Webb
  * @author Rob Tompkins
+ * @author Artsiom Yudovin
  */
 public class TomcatWebServerFactoryCustomizerTests {
 
@@ -67,6 +69,14 @@ public void setup() {
 				this.serverProperties);
 	}
 
+	@Test
+	public void customMaxSwallowSize() {
+		bind("server.tomcat.max-swallow-size=10");
+		customizeAndRunServer((server) -> assertThat(((AbstractHttp11Protocol<?>) server
+				.getTomcat().getConnector().getProtocolHandler()).getMaxSwallowSize())
+						.isEqualTo(10));
+	}
+
 	@Test
 	public void customAcceptCount() {
 		bind("server.tomcat.accept-count=10");

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

@@ -263,6 +263,7 @@ 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.max-swallow-size= # Maximum amount of request body to swallow.
 	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.