BEST_MATCHING_HANDLER_ATTRIBUTE for spring-webmvc

Issue: SPR-17518

Author: rstoyanchev

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

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2016 the original author or authors.
+ * Copyright 2002-2018 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.
@@ -55,6 +55,13 @@
  */
 public interface HandlerMapping {
 
+	/**
+	 * Name of the {@link HttpServletRequest} attribute that contains the mapped
+	 * handler for the best matching pattern.
+	 * @since 5.1.3
+	 */
+	String BEST_MATCHING_HANDLER_ATTRIBUTE = HandlerMapping.class.getName() + ".bestMatchingHandler";
+
 	/**
 	 * Name of the {@link HttpServletRequest} attribute that contains the path
 	 * within the handler mapping, in case of a pattern match, or the full

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

@@ -414,6 +414,7 @@ protected HandlerMethod lookupHandlerMethod(String lookupPath, HttpServletReques
 							"Ambiguous handler methods mapped for '" + uri + "': {" + m1 + ", " + m2 + "}");
 				}
 			}
+			request.setAttribute(BEST_MATCHING_HANDLER_ATTRIBUTE, bestMatch.handlerMethod);
 			handleMatch(bestMatch.mapping, lookupPath, request);
 			return bestMatch.handlerMethod;
 		}

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

@@ -411,6 +411,7 @@ public PathExposingHandlerInterceptor(String bestMatchingPattern, String pathWit
 		@Override
 		public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) {
 			exposePathWithinMapping(this.bestMatchingPattern, this.pathWithinMapping, request);
+			request.setAttribute(BEST_MATCHING_HANDLER_ATTRIBUTE, handler);
 			request.setAttribute(INTROSPECT_TYPE_LEVEL_MAPPING, supportsTypeLevelMappings());
 			return true;
 		}

spring-webmvc/src/test/java/org/springframework/web/servlet/handler/HandlerMethodMappingTests.java

@@ -36,6 +36,7 @@
 import org.springframework.web.context.support.StaticWebApplicationContext;
 import org.springframework.web.cors.CorsConfiguration;
 import org.springframework.web.method.HandlerMethod;
+import org.springframework.web.servlet.HandlerMapping;
 import org.springframework.web.util.UrlPathHelper;
 
 import static org.junit.Assert.assertEquals;
@@ -81,17 +82,21 @@ public void directMatch() throws Exception {
 		String key = "foo";
 		this.mapping.registerMapping(key, this.handler, this.method1);
 
-		HandlerMethod result = this.mapping.getHandlerInternal(new MockHttpServletRequest("GET", key));
+		MockHttpServletRequest request = new MockHttpServletRequest("GET", key);
+		HandlerMethod result = this.mapping.getHandlerInternal(request);
 		assertEquals(method1, result.getMethod());
+		assertEquals(result, request.getAttribute(HandlerMapping.BEST_MATCHING_HANDLER_ATTRIBUTE));
 	}
 
 	@Test
 	public void patternMatch() throws Exception {
 		this.mapping.registerMapping("/fo*", this.handler, this.method1);
 		this.mapping.registerMapping("/f*", this.handler, this.method2);
 
-		HandlerMethod result = this.mapping.getHandlerInternal(new MockHttpServletRequest("GET", "/foo"));
+		MockHttpServletRequest request = new MockHttpServletRequest("GET", "/foo");
+		HandlerMethod result = this.mapping.getHandlerInternal(request);
 		assertEquals(method1, result.getMethod());
+		assertEquals(result, request.getAttribute(HandlerMapping.BEST_MATCHING_HANDLER_ATTRIBUTE));
 	}
 
 	@Test(expected = IllegalStateException.class)

spring-webmvc/src/test/java/org/springframework/web/servlet/handler/SimpleUrlHandlerMappingTests.java

@@ -42,17 +42,17 @@ public class SimpleUrlHandlerMappingTests {
 
 	@Test
 	@SuppressWarnings("resource")
-	public void handlerBeanNotFound() throws Exception {
+	public void handlerBeanNotFound() {
 		MockServletContext sc = new MockServletContext("");
 		XmlWebApplicationContext root = new XmlWebApplicationContext();
 		root.setServletContext(sc);
-		root.setConfigLocations(new String[] {"/org/springframework/web/servlet/handler/map1.xml"});
+		root.setConfigLocations("/org/springframework/web/servlet/handler/map1.xml");
 		root.refresh();
 		XmlWebApplicationContext wac = new XmlWebApplicationContext();
 		wac.setParent(root);
 		wac.setServletContext(sc);
 		wac.setNamespace("map2err");
-		wac.setConfigLocations(new String[] {"/org/springframework/web/servlet/handler/map2err.xml"});
+		wac.setConfigLocations("/org/springframework/web/servlet/handler/map2err.xml");
 		try {
 			wac.refresh();
 			fail("Should have thrown NoSuchBeanDefinitionException");
@@ -95,7 +95,7 @@ private void checkMappings(String beanName) throws Exception {
 		MockServletContext sc = new MockServletContext("");
 		XmlWebApplicationContext wac = new XmlWebApplicationContext();
 		wac.setServletContext(sc);
-		wac.setConfigLocations(new String[] {"/org/springframework/web/servlet/handler/map2.xml"});
+		wac.setConfigLocations("/org/springframework/web/servlet/handler/map2.xml");
 		wac.refresh();
 		Object bean = wac.getBean("mainController");
 		Object otherBean = wac.getBean("otherController");
@@ -106,11 +106,13 @@ private void checkMappings(String beanName) throws Exception {
 		HandlerExecutionChain hec = getHandler(hm, req);
 		assertTrue("Handler is correct bean", hec != null && hec.getHandler() == bean);
 		assertEquals("/welcome.html", req.getAttribute(HandlerMapping.PATH_WITHIN_HANDLER_MAPPING_ATTRIBUTE));
+		assertEquals(bean, req.getAttribute(HandlerMapping.BEST_MATCHING_HANDLER_ATTRIBUTE));
 
 		req = new MockHttpServletRequest("GET", "/welcome.x");
 		hec = getHandler(hm, req);
 		assertTrue("Handler is correct bean", hec != null && hec.getHandler() == otherBean);
 		assertEquals("welcome.x", req.getAttribute(HandlerMapping.PATH_WITHIN_HANDLER_MAPPING_ATTRIBUTE));
+		assertEquals(otherBean, req.getAttribute(HandlerMapping.BEST_MATCHING_HANDLER_ATTRIBUTE));
 
 		req = new MockHttpServletRequest("GET", "/welcome/");
 		hec = getHandler(hm, req);