Polish "Configure ForwardedHeaderFilter with Tomcat's use relative redirects"

See gh-29333

Author: wilkinsona

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

@@ -87,25 +87,21 @@ public TomcatServletWebServerFactoryCustomizer tomcatServletWebServerFactoryCust
 
 	@Configuration(proxyBeanMethods = false)
 	@ConditionalOnProperty(value = "server.forward-headers-strategy", havingValue = "framework")
+	@ConditionalOnMissingFilterBean(ForwardedHeaderFilter.class)
 	static class ForwardedHeaderFilterConfiguration {
 
 		@Bean
 		@ConditionalOnClass(name = "org.apache.catalina.startup.Tomcat")
 		@ConditionalOnMissingFilterBean(ForwardedHeaderFilter.class)
-		public FilterRegistrationBean<ForwardedHeaderFilter> tomcatForwardedHeaderFilter(
-				ServerProperties serverProperties) {
-			return createForwardedHeaderFilter(serverProperties.getTomcat().isUseRelativeRedirects());
+		ForwardedHeaderFilterCustomizer tomcatForwardedHeaderFilterCustomizer(ServerProperties serverProperties) {
+			return (filter) -> filter.setRelativeRedirects(serverProperties.getTomcat().isUseRelativeRedirects());
 		}
 
 		@Bean
-		@ConditionalOnMissingFilterBean(ForwardedHeaderFilter.class)
-		public FilterRegistrationBean<ForwardedHeaderFilter> defaultForwardedHeaderFilter() {
-			return createForwardedHeaderFilter(false);
-		}
-
-		private FilterRegistrationBean<ForwardedHeaderFilter> createForwardedHeaderFilter(boolean relativeRedirects) {
+		FilterRegistrationBean<ForwardedHeaderFilter> forwardedHeaderFilter(
+				ObjectProvider<ForwardedHeaderFilterCustomizer> customizerProvider) {
 			ForwardedHeaderFilter filter = new ForwardedHeaderFilter();
-			filter.setRelativeRedirects(relativeRedirects);
+			customizerProvider.ifAvailable((customizer) -> customizer.customize(filter));
 			FilterRegistrationBean<ForwardedHeaderFilter> registration = new FilterRegistrationBean<>(filter);
 			registration.setDispatcherTypes(DispatcherType.REQUEST, DispatcherType.ASYNC, DispatcherType.ERROR);
 			registration.setOrder(Ordered.HIGHEST_PRECEDENCE);
@@ -114,6 +110,12 @@ private FilterRegistrationBean<ForwardedHeaderFilter> createForwardedHeaderFilte
 
 	}
 
+	interface ForwardedHeaderFilterCustomizer {
+
+		void customize(ForwardedHeaderFilter filter);
+
+	}
+
 	/**
 	 * Registers a {@link WebServerFactoryCustomizerBeanPostProcessor}. Registered via
 	 * {@link ImportBeanDefinitionRegistrar} for early registration.

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

@@ -57,7 +57,6 @@
 import org.springframework.context.annotation.Bean;
 import org.springframework.context.annotation.Configuration;
 import org.springframework.stereotype.Component;
-import org.springframework.test.util.ReflectionTestUtils;
 import org.springframework.web.filter.ForwardedHeaderFilter;
 import org.springframework.web.servlet.DispatcherServlet;
 import org.springframework.web.servlet.FrameworkServlet;
@@ -353,6 +352,7 @@ void forwardedHeaderFilterShouldBeConfigured() {
 			assertThat(context).hasSingleBean(FilterRegistrationBean.class);
 			Filter filter = context.getBean(FilterRegistrationBean.class).getFilter();
 			assertThat(filter).isInstanceOf(ForwardedHeaderFilter.class);
+			assertThat(filter).extracting("relativeRedirects").isEqualTo(false);
 		});
 	}
 
@@ -376,11 +376,24 @@ void relativeRedirectsShouldBeEnabledWhenUsingTomcatContainerAndUseRelativeRedir
 						.withConfiguration(AutoConfigurations.of(ServletWebServerFactoryAutoConfiguration.class))
 						.withPropertyValues("server.forward-headers-strategy=framework",
 								"server.tomcat.use-relative-redirects=true");
+		runner.run((context) -> {
+			Filter filter = context.getBean(FilterRegistrationBean.class).getFilter();
+			assertThat(filter).isInstanceOf(ForwardedHeaderFilter.class);
+			assertThat(filter).extracting("relativeRedirects").isEqualTo(true);
+		});
+	}
 
+	@Test
+	void relativeRedirectsShouldNotBeEnabledWhenUsingTomcatContainerAndNotUsingRelativeRedirects() {
+		WebApplicationContextRunner runner = new WebApplicationContextRunner(
+				AnnotationConfigServletWebServerApplicationContext::new)
+						.withConfiguration(AutoConfigurations.of(ServletWebServerFactoryAutoConfiguration.class))
+						.withPropertyValues("server.forward-headers-strategy=framework",
+								"server.tomcat.use-relative-redirects=false");
 		runner.run((context) -> {
 			Filter filter = context.getBean(FilterRegistrationBean.class).getFilter();
-			Boolean relativeRedirects = (Boolean) ReflectionTestUtils.getField(filter, "relativeRedirects");
-			assertThat(relativeRedirects).isTrue();
+			assertThat(filter).isInstanceOf(ForwardedHeaderFilter.class);
+			assertThat(filter).extracting("relativeRedirects").isEqualTo(false);
 		});
 	}
 
@@ -391,11 +404,10 @@ void relativeRedirectsShouldNotBeEnabledWhenNotUsingTomcatContainer() {
 						.withClassLoader(new FilteredClassLoader(Tomcat.class))
 						.withConfiguration(AutoConfigurations.of(ServletWebServerFactoryAutoConfiguration.class))
 						.withPropertyValues("server.forward-headers-strategy=framework");
-
 		runner.run((context) -> {
 			Filter filter = context.getBean(FilterRegistrationBean.class).getFilter();
-			Boolean relativeRedirects = (Boolean) ReflectionTestUtils.getField(filter, "relativeRedirects");
-			assertThat(relativeRedirects).isFalse();
+			assertThat(filter).isInstanceOf(ForwardedHeaderFilter.class);
+			assertThat(filter).extracting("relativeRedirects").isEqualTo(false);
 		});
 	}