Auto-configure ProblemDetails support

This commit auto-configures ProblemDetails support for both Spring MVC
and Spring WebFlux, contributing a `@ControllerAdvice` annotated
`ResponseEntityExceptionHandler` bean if the
`spring.mvc.problemdetails.enabled` or
`spring.webflux.problemdetails.enabled` properties are set to `true`.

Closes gh-32634

spring-boot-project/spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/data/r2dbc/R2dbcDataAutoConfiguration.java

@@ -39,6 +39,7 @@
 import org.springframework.data.r2dbc.dialect.R2dbcDialect;
 import org.springframework.data.r2dbc.mapping.R2dbcMappingContext;
 import org.springframework.data.relational.RelationalManagedTypes;
+import org.springframework.data.relational.core.mapping.DefaultNamingStrategy;
 import org.springframework.data.relational.core.mapping.NamingStrategy;
 import org.springframework.data.relational.core.mapping.Table;
 import org.springframework.r2dbc.core.DatabaseClient;
@@ -79,11 +80,10 @@ static RelationalManagedTypes r2dbcManagedTypes(ApplicationContext applicationCo
 
 	@Bean
 	@ConditionalOnMissingBean
-	@SuppressWarnings("deprecation")
 	public R2dbcMappingContext r2dbcMappingContext(ObjectProvider<NamingStrategy> namingStrategy,
 			R2dbcCustomConversions r2dbcCustomConversions, RelationalManagedTypes r2dbcManagedTypes) {
 		R2dbcMappingContext relationalMappingContext = new R2dbcMappingContext(
-				namingStrategy.getIfAvailable(() -> NamingStrategy.INSTANCE));
+				namingStrategy.getIfAvailable(() -> DefaultNamingStrategy.INSTANCE));
 		relationalMappingContext.setSimpleTypeHolder(r2dbcCustomConversions.getSimpleTypeHolder());
 		relationalMappingContext.setManagedTypes(r2dbcManagedTypes);
 		return relationalMappingContext;

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

@@ -0,0 +1,31 @@
+/*
+ * Copyright 2012-2022 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
+ *
+ *      https://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.reactive;
+
+import org.springframework.web.bind.annotation.ControllerAdvice;
+import org.springframework.web.reactive.result.method.annotation.ResponseEntityExceptionHandler;
+
+/**
+ * {@code @ControllerAdvice} annotated {@link ResponseEntityExceptionHandler} that is
+ * auto-configured for problem details support.
+ *
+ * @author Brian Clozel
+ */
+@ControllerAdvice
+final class ProblemDetailsExceptionHandler extends ResponseEntityExceptionHandler {
+
+}

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

@@ -74,6 +74,7 @@
 import org.springframework.web.reactive.result.method.annotation.ArgumentResolverConfigurer;
 import org.springframework.web.reactive.result.method.annotation.RequestMappingHandlerAdapter;
 import org.springframework.web.reactive.result.method.annotation.RequestMappingHandlerMapping;
+import org.springframework.web.reactive.result.method.annotation.ResponseEntityExceptionHandler;
 import org.springframework.web.reactive.result.view.ViewResolver;
 import org.springframework.web.server.WebSession;
 import org.springframework.web.server.adapter.WebHttpHandlerBuilder;
@@ -334,6 +335,18 @@ ResourceChainResourceHandlerRegistrationCustomizer resourceHandlerRegistrationCu
 
 	}
 
+	@Configuration(proxyBeanMethods = false)
+	@ConditionalOnProperty(prefix = "spring.webflux.problemdetails", name = "enabled", havingValue = "true")
+	static class ProblemDetailsErrorHandlingConfiguration {
+
+		@Bean
+		@ConditionalOnMissingBean(ResponseEntityExceptionHandler.class)
+		ProblemDetailsExceptionHandler problemDetailsExceptionHandler() {
+			return new ProblemDetailsExceptionHandler();
+		}
+
+	}
+
 	static final class MaxIdleTimeInMemoryWebSessionStore extends InMemoryWebSessionStore {
 
 		private final Duration timeout;

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

@@ -36,6 +36,8 @@ public class WebFluxProperties {
 
 	private final Format format = new Format();
 
+	private final Problemdetails problemdetails = new Problemdetails();
+
 	/**
 	 * Path pattern used for static resources.
 	 */
@@ -74,6 +76,10 @@ public Format getFormat() {
 		return this.format;
 	}
 
+	public Problemdetails getProblemdetails() {
+		return this.problemdetails;
+	}
+
 	public String getStaticPathPattern() {
 		return this.staticPathPattern;
 	}
@@ -133,4 +139,21 @@ public void setDateTime(String dateTime) {
 
 	}
 
+	public static class Problemdetails {
+
+		/**
+		 * Whether RFC 7807 Problem Details support should be enabled.
+		 */
+		private boolean enabled = false;
+
+		public boolean isEnabled() {
+			return this.enabled;
+		}
+
+		public void setEnabled(boolean enabled) {
+			this.enabled = enabled;
+		}
+
+	}
+
 }

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

@@ -0,0 +1,31 @@
+/*
+ * Copyright 2012-2022 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
+ *
+ *      https://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.servlet;
+
+import org.springframework.web.bind.annotation.ControllerAdvice;
+import org.springframework.web.servlet.mvc.method.annotation.ResponseEntityExceptionHandler;
+
+/**
+ * {@code @ControllerAdvice} annotated {@link ResponseEntityExceptionHandler} that is
+ * auto-configured for problem details support.
+ *
+ * @author Brian Clozel
+ */
+@ControllerAdvice
+final class ProblemDetailsExceptionHandler extends ResponseEntityExceptionHandler {
+
+}

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

@@ -114,6 +114,7 @@
 import org.springframework.web.servlet.mvc.method.annotation.ExceptionHandlerExceptionResolver;
 import org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter;
 import org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerMapping;
+import org.springframework.web.servlet.mvc.method.annotation.ResponseEntityExceptionHandler;
 import org.springframework.web.servlet.resource.EncodedResourceResolver;
 import org.springframework.web.servlet.resource.ResourceResolver;
 import org.springframework.web.servlet.resource.ResourceUrlProvider;
@@ -643,6 +644,18 @@ private ResourceResolver getVersionResourceResolver(Strategy properties) {
 
 	}
 
+	@Configuration(proxyBeanMethods = false)
+	@ConditionalOnProperty(prefix = "spring.mvc.problemdetails", name = "enabled", havingValue = "true")
+	static class ProblemDetailsErrorHandlingConfiguration {
+
+		@Bean
+		@ConditionalOnMissingBean(ResponseEntityExceptionHandler.class)
+		ProblemDetailsExceptionHandler problemDetailsExceptionHandler() {
+			return new ProblemDetailsExceptionHandler();
+		}
+
+	}
+
 	/**
 	 * Decorator to make
 	 * {@link org.springframework.web.accept.PathExtensionContentNegotiationStrategy}

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

@@ -106,6 +106,8 @@ public class WebMvcProperties {
 
 	private final Pathmatch pathmatch = new Pathmatch();
 
+	private final Problemdetails problemdetails = new Problemdetails();
+
 	public DefaultMessageCodesResolver.Format getMessageCodesResolverFormat() {
 		return this.messageCodesResolverFormat;
 	}
@@ -213,6 +215,10 @@ public Pathmatch getPathmatch() {
 		return this.pathmatch;
 	}
 
+	public Problemdetails getProblemdetails() {
+		return this.problemdetails;
+	}
+
 	public static class Async {
 
 		/**
@@ -447,4 +453,21 @@ public enum MatchingStrategy {
 
 	}
 
+	public static class Problemdetails {
+
+		/**
+		 * Whether RFC 7807 Problem Details support should be enabled.
+		 */
+		private boolean enabled = false;
+
+		public boolean isEnabled() {
+			return this.enabled;
+		}
+
+		public void setEnabled(boolean enabled) {
+			this.enabled = enabled;
+		}
+
+	}
+
 }

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

@@ -70,6 +70,7 @@
 import org.springframework.util.StringUtils;
 import org.springframework.validation.Validator;
 import org.springframework.validation.beanvalidation.LocalValidatorFactoryBean;
+import org.springframework.web.bind.annotation.ControllerAdvice;
 import org.springframework.web.filter.reactive.HiddenHttpMethodFilter;
 import org.springframework.web.reactive.HandlerMapping;
 import org.springframework.web.reactive.accept.RequestedContentTypeResolver;
@@ -85,6 +86,7 @@
 import org.springframework.web.reactive.result.method.HandlerMethodArgumentResolver;
 import org.springframework.web.reactive.result.method.annotation.RequestMappingHandlerAdapter;
 import org.springframework.web.reactive.result.method.annotation.RequestMappingHandlerMapping;
+import org.springframework.web.reactive.result.method.annotation.ResponseEntityExceptionHandler;
 import org.springframework.web.reactive.result.view.ViewResolutionResultHandler;
 import org.springframework.web.reactive.result.view.ViewResolver;
 import org.springframework.web.server.ServerWebExchange;
@@ -622,6 +624,25 @@ void propertiesAreNotEnabledInNonWebApplication(Class<?> propertiesClass) {
 				.run((context) -> assertThat(context).doesNotHaveBean(propertiesClass));
 	}
 
+	@Test
+	void problemDetailsDisabledByDefault() {
+		this.contextRunner.run((context) -> assertThat(context).doesNotHaveBean(ProblemDetailsExceptionHandler.class));
+	}
+
+	@Test
+	void problemDetailsEnabledAddsExceptionHandler() {
+		this.contextRunner.withPropertyValues("spring.webflux.problemdetails.enabled:true")
+				.run((context) -> assertThat(context).hasSingleBean(ProblemDetailsExceptionHandler.class));
+	}
+
+	@Test
+	void problemDetailsBacksOffWhenExceptionHandler() {
+		this.contextRunner.withPropertyValues("spring.webflux.problemdetails.enabled:true")
+				.withUserConfiguration(CustomExceptionResolverConfiguration.class)
+				.run((context) -> assertThat(context).doesNotHaveBean(ProblemDetailsExceptionHandler.class)
+						.hasSingleBean(CustomExceptionResolver.class));
+	}
+
 	private ContextConsumer<ReactiveWebApplicationContext> assertExchangeWithSession(
 			Consumer<MockServerWebExchange> exchange) {
 		return (context) -> {
@@ -911,4 +932,19 @@ static class LowPrecedenceConfigurer implements WebFluxConfigurer {
 
 	}
 
+	@Configuration(proxyBeanMethods = false)
+	static class CustomExceptionResolverConfiguration {
+
+		@Bean
+		CustomExceptionResolver customExceptionResolver() {
+			return new CustomExceptionResolver();
+		}
+
+	}
+
+	@ControllerAdvice
+	static class CustomExceptionResolver extends ResponseEntityExceptionHandler {
+
+	}
+
 }

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

@@ -77,6 +77,7 @@
 import org.springframework.validation.beanvalidation.LocalValidatorFactoryBean;
 import org.springframework.web.accept.ContentNegotiationManager;
 import org.springframework.web.accept.ParameterContentNegotiationStrategy;
+import org.springframework.web.bind.annotation.ControllerAdvice;
 import org.springframework.web.bind.support.ConfigurableWebBindingInitializer;
 import org.springframework.web.context.support.AnnotationConfigWebApplicationContext;
 import org.springframework.web.cors.UrlBasedCorsConfigurationSource;
@@ -106,6 +107,7 @@
 import org.springframework.web.servlet.mvc.method.annotation.ExceptionHandlerExceptionResolver;
 import org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter;
 import org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerMapping;
+import org.springframework.web.servlet.mvc.method.annotation.ResponseEntityExceptionHandler;
 import org.springframework.web.servlet.mvc.support.DefaultHandlerExceptionResolver;
 import org.springframework.web.servlet.resource.CachingResourceResolver;
 import org.springframework.web.servlet.resource.CachingResourceTransformer;
@@ -959,6 +961,25 @@ void addResourceHandlersAppliesToChildAndParentContext() {
 		}
 	}
 
+	@Test
+	void problemDetailsDisabledByDefault() {
+		this.contextRunner.run((context) -> assertThat(context).doesNotHaveBean(ProblemDetailsExceptionHandler.class));
+	}
+
+	@Test
+	void problemDetailsEnabledAddsExceptionHandler() {
+		this.contextRunner.withPropertyValues("spring.mvc.problemdetails.enabled:true")
+				.run((context) -> assertThat(context).hasSingleBean(ProblemDetailsExceptionHandler.class));
+	}
+
+	@Test
+	void problemDetailsBacksOffWhenExceptionHandler() {
+		this.contextRunner.withPropertyValues("spring.mvc.problemdetails.enabled:true")
+				.withUserConfiguration(CustomExceptionResolverConfiguration.class)
+				.run((context) -> assertThat(context).doesNotHaveBean(ProblemDetailsExceptionHandler.class)
+						.hasSingleBean(CustomExceptionResolver.class));
+	}
+
 	private void assertResourceHttpRequestHandler(AssertableWebApplicationContext context,
 			Consumer<ResourceHttpRequestHandler> handlerConsumer) {
 		Map<String, Object> handlerMap = getHandlerMap(context.getBean("resourceHandlerMapping", HandlerMapping.class));
@@ -1485,4 +1506,19 @@ public void addResourceHandlers(ResourceHandlerRegistry registry) {
 
 	}
 
+	@Configuration(proxyBeanMethods = false)
+	static class CustomExceptionResolverConfiguration {
+
+		@Bean
+		CustomExceptionResolver customExceptionResolver() {
+			return new CustomExceptionResolver();
+		}
+
+	}
+
+	@ControllerAdvice
+	static class CustomExceptionResolver extends ResponseEntityExceptionHandler {
+
+	}
+
 }

spring-boot-project/spring-boot-docs/src/docs/asciidoc/web/reactive.adoc

@@ -123,6 +123,23 @@ For machine clients, it produces a JSON response with details of the error, the
 For browser clients, there is a "`whitelabel`" error handler that renders the same data in HTML format.
 You can also provide your own HTML templates to display errors (see the <<web#web.reactive.webflux.error-handling.error-pages,next section>>).
 
+Before customizing error handling in Spring Boot directly, you can leverage the {spring-framework-docs}/web-reactive.html#webflux-ann-rest-exceptions[RFC 7807 Problem Details] support in Spring WebFlux.
+Spring WebFlux can produce custom error messages with the `application/problem+json` media type, like:
+
+[source,json,indent=0,subs="verbatim"]
+----
+{
+  "type": "https://example.org/problems/unknown-project",
+  "title": "Unknown project",
+  "status": 404,
+  "detail": "No project found for id 'spring-unknown'",
+  "instance": "/projects/spring-unknown"
+}
+----
+
+This support can be enabled by setting configprop:spring.webflux.problemdetails.enabled[] to `true`.
+
+
 The first step to customizing this feature often involves using the existing mechanism but replacing or augmenting the error contents.
 For that, you can add a bean of type `ErrorAttributes`.
 

spring-boot-project/spring-boot-docs/src/docs/asciidoc/web/servlet.adoc

@@ -298,6 +298,22 @@ TIP: The `BasicErrorController` can be used as a base class for a custom `ErrorC
 This is particularly useful if you want to add a handler for a new content type (the default is to handle `text/html` specifically and provide a fallback for everything else).
 To do so, extend `BasicErrorController`, add a public method with a `@RequestMapping` that has a `produces` attribute, and create a bean of your new type.
 
+As of Spring Framework 6.0, {spring-framework-docs}/web.html#mvc-ann-rest-exceptions[RFC 7807 Problem Details] is supported.
+Spring MVC can produce custom error messages with the `application/problem+json` media type, like:
+
+[source,json,indent=0,subs="verbatim"]
+----
+{
+  "type": "https://example.org/problems/unknown-project",
+  "title": "Unknown project",
+  "status": 404,
+  "detail": "No project found for id 'spring-unknown'",
+  "instance": "/projects/spring-unknown"
+}
+----
+
+This support can be enabled by setting configprop:spring.mvc.problemdetails.enabled[] to `true`.
+
 You can also define a class annotated with `@ControllerAdvice` to customize the JSON document to return for a particular controller and/or exception type, as shown in the following example:
 
 include::code:MyControllerAdvice[]