Expose mapped handler as an exchange attribute

Issue: SPR-15564

spring-webflux/src/main/java/org/springframework/web/reactive/HandlerMapping.java

@@ -31,29 +31,31 @@ import org.springframework.web.server.ServerWebExchange;
 public interface HandlerMapping {
 
 	/**
-	 * Name of the {@link ServerWebExchange} attribute that contains the
-	 * best matching pattern within the handler mapping.
-	 * <p>Note: This attribute is not required to be supported by all
-	 * HandlerMapping implementations. URL-based HandlerMappings will
-	 * typically support it, but handlers should not necessarily expect
-	 * this request attribute to be present in all scenarios.
+	 * Name of the {@link ServerWebExchange#getAttributes() attribute} that
+	 * contains the mapped handler for the best matching pattern.
+	 */
+	String BEST_MATCHING_HANDLER_ATTRIBUTE = HandlerMapping.class.getName() + ".bestMatchingHandler";
+
+	/**
+	 * Name of the {@link ServerWebExchange#getAttributes() attribute} that
+	 * contains the best matching pattern within the handler mapping.
 	 */
 	String BEST_MATCHING_PATTERN_ATTRIBUTE = HandlerMapping.class.getName() + ".bestMatchingPattern";
 
 	/**
-	 * Name of the {@link ServerWebExchange} attribute that contains the path
-	 * within the handler mapping, in case of a pattern match, or the full
-	 * relevant URI (typically within the DispatcherServlet's mapping) else.
+	 * Name of the {@link ServerWebExchange#getAttributes() attribute} that
+	 * contains the path within the handler mapping, in case of a pattern match
+	 * such as {@code "/static/**"} or the full relevant URI otherwise.
 	 * <p>Note: This attribute is not required to be supported by all
 	 * HandlerMapping implementations. URL-based HandlerMappings will
-	 * typically support it, but handlers should not necessarily expect
+	 * typically support it but handlers should not necessarily expect
 	 * this request attribute to be present in all scenarios.
 	 */
 	String PATH_WITHIN_HANDLER_MAPPING_ATTRIBUTE = HandlerMapping.class.getName() + ".pathWithinHandlerMapping";
 
 	/**
-	 * Name of the {@link ServerWebExchange} attribute that contains the URI
-	 * templates map, mapping variable names to values.
+	 * Name of the {@link ServerWebExchange#getAttributes() attribute} that
+	 * contains the URI templates map mapping variable names to values.
 	 * <p>Note: This attribute is not required to be supported by all
 	 * HandlerMapping implementations. URL-based HandlerMappings will
 	 * typically support it, but handlers should not necessarily expect
@@ -62,8 +64,9 @@ public interface HandlerMapping {
 	String URI_TEMPLATE_VARIABLES_ATTRIBUTE = HandlerMapping.class.getName() + ".uriTemplateVariables";
 
 	/**
-	 * Name of the {@link ServerWebExchange} attribute that contains a map with
-	 * URI matrix variables.
+	 * Name of the {@link ServerWebExchange#getAttributes() attribute} that
+	 * contains a map with URI variable names and a corresponding MultiValueMap
+	 * of URI matrix variables for each.
 	 * <p>Note: This attribute is not required to be supported by all
 	 * HandlerMapping implementations and may also not be present depending on
 	 * whether the HandlerMapping is configured to keep matrix variable content
@@ -72,8 +75,8 @@ public interface HandlerMapping {
 	String MATRIX_VARIABLES_ATTRIBUTE = HandlerMapping.class.getName() + ".matrixVariables";
 
 	/**
-	 * Name of the {@link ServerWebExchange} attribute that contains the set of
-	 * producible MediaTypes applicable to the mapped handler.
+	 * Name of the {@link ServerWebExchange#getAttributes() attribute} containing
+	 * the set of producible MediaType's applicable to the mapped handler.
 	 * <p>Note: This attribute is not required to be supported by all
 	 * HandlerMapping implementations. Handlers should not necessarily expect
 	 * this request attribute to be present in all scenarios.

spring-webflux/src/main/java/org/springframework/web/reactive/handler/AbstractUrlHandlerMapping.java

@@ -145,8 +145,9 @@ public abstract class AbstractUrlHandlerMapping extends AbstractHandlerMapping {
 
 		validateHandler(handler, exchange);
 
-		exchange.getAttributes().put(PATH_WITHIN_HANDLER_MAPPING_ATTRIBUTE, pathWithinMapping);
+		exchange.getAttributes().put(BEST_MATCHING_HANDLER_ATTRIBUTE, handler);
 		exchange.getAttributes().put(BEST_MATCHING_PATTERN_ATTRIBUTE, bestMatch);
+		exchange.getAttributes().put(PATH_WITHIN_HANDLER_MAPPING_ATTRIBUTE, pathWithinMapping);
 
 		return handler;
 	}

spring-webflux/src/main/java/org/springframework/web/reactive/result/method/AbstractHandlerMethodMapping.java

@@ -322,7 +322,7 @@ public abstract class AbstractHandlerMethodMapping<T> extends AbstractHandlerMap
 							lookupPath + "': {" + m1 + ", " + m2 + "}");
 				}
 			}
-			handleMatch(bestMatch.mapping, lookupPath, exchange);
+			handleMatch(bestMatch.mapping, bestMatch.handlerMethod, lookupPath, exchange);
 			return bestMatch.handlerMethod;
 		}
 		else {
@@ -342,10 +342,12 @@ public abstract class AbstractHandlerMethodMapping<T> extends AbstractHandlerMap
 	/**
 	 * Invoked when a matching mapping is found.
 	 * @param mapping the matching mapping
+	 * @param handlerMethod the matching method
 	 * @param lookupPath the lookup path within the current mapping
 	 * @param exchange the current exchange
 	 */
-	protected void handleMatch(T mapping, String lookupPath, ServerWebExchange exchange) {
+	protected void handleMatch(T mapping, HandlerMethod handlerMethod, String lookupPath,
+			ServerWebExchange exchange) {
 	}
 
 	/**

spring-webflux/src/main/java/org/springframework/web/reactive/result/method/RequestMappingInfoHandlerMapping.java

@@ -106,8 +106,10 @@ public abstract class RequestMappingInfoHandlerMapping extends AbstractHandlerMe
 	 * @see HandlerMapping#PRODUCIBLE_MEDIA_TYPES_ATTRIBUTE
 	 */
 	@Override
-	protected void handleMatch(RequestMappingInfo info, String lookupPath, ServerWebExchange exchange) {
-		super.handleMatch(info, lookupPath, exchange);
+	protected void handleMatch(RequestMappingInfo info, HandlerMethod handlerMethod, String lookupPath,
+			ServerWebExchange exchange) {
+
+		super.handleMatch(info, handlerMethod, lookupPath, exchange);
 
 		PathPattern bestPattern;
 		Map<String, String> uriVariables;
@@ -133,6 +135,7 @@ public abstract class RequestMappingInfoHandlerMapping extends AbstractHandlerMe
 			));
 		}
 
+		exchange.getAttributes().put(BEST_MATCHING_HANDLER_ATTRIBUTE, handlerMethod);
 		exchange.getAttributes().put(BEST_MATCHING_PATTERN_ATTRIBUTE, bestPattern);
 		exchange.getAttributes().put(URI_TEMPLATE_VARIABLES_ATTRIBUTE, uriVariables);
 

spring-webflux/src/test/java/org/springframework/web/reactive/result/method/RequestMappingInfoHandlerMappingTests.java

@@ -39,6 +39,7 @@ import org.springframework.http.HttpMethod;
 import org.springframework.http.MediaType;
 import org.springframework.mock.http.server.reactive.test.MockServerHttpRequest;
 import org.springframework.stereotype.Controller;
+import org.springframework.util.ClassUtils;
 import org.springframework.util.MultiValueMap;
 import org.springframework.web.bind.annotation.GetMapping;
 import org.springframework.web.bind.annotation.PutMapping;
@@ -60,6 +61,7 @@ import static org.hamcrest.CoreMatchers.containsString;
 import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertNotNull;
 import static org.junit.Assert.assertNull;
+import static org.junit.Assert.assertSame;
 import static org.junit.Assert.assertThat;
 import static org.springframework.mock.http.server.reactive.test.MockServerHttpRequest.get;
 import static org.springframework.mock.http.server.reactive.test.MockServerHttpRequest.method;
@@ -69,6 +71,8 @@ import static org.springframework.web.bind.annotation.RequestMethod.OPTIONS;
 import static org.springframework.web.method.MvcAnnotationPredicates.getMapping;
 import static org.springframework.web.method.MvcAnnotationPredicates.requestMapping;
 import static org.springframework.web.method.ResolvableMethod.on;
+import static org.springframework.web.reactive.HandlerMapping.BEST_MATCHING_HANDLER_ATTRIBUTE;
+import static org.springframework.web.reactive.HandlerMapping.BEST_MATCHING_PATTERN_ATTRIBUTE;
 import static org.springframework.web.reactive.result.method.RequestMappingInfo.paths;
 
 /**
@@ -77,6 +81,9 @@ import static org.springframework.web.reactive.result.method.RequestMappingInfo.
  */
 public class RequestMappingInfoHandlerMappingTests {
 
+	private static final HandlerMethod handlerMethod = new HandlerMethod(new TestController(),
+			ClassUtils.getMethod(TestController.class, "dummy"));
+
 	private TestRequestMappingInfoHandlerMapping handlerMapping;
 
 
@@ -169,8 +176,8 @@ public class RequestMappingInfoHandlerMappingTests {
 		Mono<Object> mono = this.handlerMapping.getHandler(exchange);
 
 		assertError(mono, UnsupportedMediaTypeStatusException.class,
-				ex -> assertEquals("Response status 415 with reason \"Invalid mime type \"bogus\": does not contain '/'\"",
-						ex.getMessage()));
+				ex -> assertEquals("Response status 415 with reason \"Invalid mime type \"bogus\": " +
+								"does not contain '/'\"", ex.getMessage()));
 	}
 
 	@Test  // SPR-8462
@@ -219,7 +226,7 @@ public class RequestMappingInfoHandlerMappingTests {
 		String lookupPath = exchange.getRequest().getPath().pathWithinApplication().value();
 
 		RequestMappingInfo key = paths("/{path1}/{path2}").build();
-		this.handlerMapping.handleMatch(key, lookupPath, exchange);
+		this.handlerMapping.handleMatch(key, handlerMethod, lookupPath, exchange);
 
 		String name = HandlerMapping.URI_TEMPLATE_VARIABLES_ATTRIBUTE;
 		Map<String, String> uriVariables = (Map<String, String>) exchange.getAttributes().get(name);
@@ -236,7 +243,7 @@ public class RequestMappingInfoHandlerMappingTests {
 		ServerWebExchange exchange = method(HttpMethod.GET, url).toExchange();
 
 		String lookupPath = exchange.getRequest().getPath().pathWithinApplication().value();
-		this.handlerMapping.handleMatch(key, lookupPath, exchange);
+		this.handlerMapping.handleMatch(key, handlerMethod, lookupPath, exchange);
 
 		String name = HandlerMapping.URI_TEMPLATE_VARIABLES_ATTRIBUTE;
 		@SuppressWarnings("unchecked")
@@ -252,11 +259,13 @@ public class RequestMappingInfoHandlerMappingTests {
 		RequestMappingInfo key = paths("/{path1}/2", "/**").build();
 		ServerWebExchange exchange = get("/1/2").toExchange();
 		String lookupPath = exchange.getRequest().getPath().pathWithinApplication().value();
-		this.handlerMapping.handleMatch(key, lookupPath, exchange);
+		this.handlerMapping.handleMatch(key, handlerMethod, lookupPath, exchange);
 
-		PathPattern bestMatch = (PathPattern) exchange.getAttributes()
-				.get(HandlerMapping.BEST_MATCHING_PATTERN_ATTRIBUTE);
+		PathPattern bestMatch = (PathPattern) exchange.getAttributes().get(BEST_MATCHING_PATTERN_ATTRIBUTE);
 		assertEquals("/{path1}/2", bestMatch.getPatternString());
+
+		HandlerMethod mapped = (HandlerMethod) exchange.getAttributes().get(BEST_MATCHING_HANDLER_ATTRIBUTE);
+		assertSame(handlerMethod, mapped);
 	}
 
 	@Test
@@ -264,10 +273,9 @@ public class RequestMappingInfoHandlerMappingTests {
 		RequestMappingInfo key = paths().build();
 		ServerWebExchange exchange = get("/1/2").toExchange();
 		String lookupPath = exchange.getRequest().getPath().pathWithinApplication().value();
-		this.handlerMapping.handleMatch(key, lookupPath, exchange);
+		this.handlerMapping.handleMatch(key, handlerMethod, lookupPath, exchange);
 
-		PathPattern bestMatch = (PathPattern) exchange.getAttributes()
-				.get(HandlerMapping.BEST_MATCHING_PATTERN_ATTRIBUTE);
+		PathPattern bestMatch = (PathPattern) exchange.getAttributes().get(BEST_MATCHING_PATTERN_ATTRIBUTE);
 		assertEquals("/1/2", bestMatch.getPatternString());
 	}
 
@@ -330,7 +338,6 @@ public class RequestMappingInfoHandlerMappingTests {
 				.consumeErrorWith(error -> {
 					assertEquals(exceptionClass, error.getClass());
 					consumer.accept((T) error);
-
 				})
 				.verify();
 	}
@@ -375,19 +382,19 @@ public class RequestMappingInfoHandlerMappingTests {
 	private void handleMatch(ServerWebExchange exchange, String pattern) {
 		RequestMappingInfo info = paths(pattern).build();
 		String lookupPath = exchange.getRequest().getPath().pathWithinApplication().value();
-		this.handlerMapping.handleMatch(info, lookupPath, exchange);
+		this.handlerMapping.handleMatch(info, handlerMethod, lookupPath, exchange);
 	}
 
 	@SuppressWarnings("unchecked")
 	private MultiValueMap<String, String> getMatrixVariables(ServerWebExchange exchange, String uriVarName) {
-		String attrName = HandlerMapping.MATRIX_VARIABLES_ATTRIBUTE;
-		return ((Map<String, MultiValueMap<String, String>>) exchange.getAttributes().get(attrName)).get(uriVarName);
+		return ((Map<String, MultiValueMap<String, String>>) exchange.getAttributes()
+				.get(HandlerMapping.MATRIX_VARIABLES_ATTRIBUTE)).get(uriVarName);
 	}
 
 	@SuppressWarnings("unchecked")
 	private Map<String, String> getUriTemplateVariables(ServerWebExchange exchange) {
-		String attrName = HandlerMapping.URI_TEMPLATE_VARIABLES_ATTRIBUTE;
-		return (Map<String, String>) exchange.getAttributes().get(attrName);
+		return (Map<String, String>) exchange.getAttributes()
+				.get(HandlerMapping.URI_TEMPLATE_VARIABLES_ATTRIBUTE);
 	}
 
 
@@ -446,6 +453,8 @@ public class RequestMappingInfoHandlerMappingTests {
 			headers.add("Allow", "PUT,POST");
 			return headers;
 		}
+
+		public void dummy() { }
 	}
 
 

spring-webmvc/src/main/java/org/springframework/web/servlet/HandlerMapping.java

@@ -96,11 +96,11 @@ public interface HandlerMapping {
 
 	/**
 	 * Name of the {@link HttpServletRequest} attribute that contains a map with
-	 * URI matrix variables.
+	 * URI variable names and a corresponding MultiValueMap of URI matrix
+	 * variables for each.
 	 * <p>Note: This attribute is not required to be supported by all
 	 * HandlerMapping implementations and may also not be present depending on
 	 * whether the HandlerMapping is configured to keep matrix variable content
-	 * in the request URI.
 	 */
 	String MATRIX_VARIABLES_ATTRIBUTE = HandlerMapping.class.getName() + ".matrixVariables";