WebFlux AbstractUrlHandlerMapping support URI vars

Closes gh-25648

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

@@ -126,11 +126,14 @@ public abstract class AbstractUrlHandlerMapping extends AbstractHandlerMapping {
 
 		PathPattern pattern = matches.get(0);
 		PathContainer pathWithinMapping = pattern.extractPathWithinPattern(lookupPath);
-		return handleMatch(this.handlerMap.get(pattern), pattern, pathWithinMapping, exchange);
+		PathPattern.PathMatchInfo matchInfo = pattern.matchAndExtract(lookupPath);
+		Assert.notNull(matchInfo, "Expected a match");
+
+		return handleMatch(this.handlerMap.get(pattern), pattern, pathWithinMapping, matchInfo, exchange);
 	}
 
 	private Object handleMatch(Object handler, PathPattern bestMatch, PathContainer pathWithinMapping,
-			ServerWebExchange exchange) {
+			PathPattern.PathMatchInfo matchInfo, ServerWebExchange exchange) {
 
 		// Bean name or resolved handler?
 		if (handler instanceof String) {
@@ -143,6 +146,7 @@ public abstract class AbstractUrlHandlerMapping extends AbstractHandlerMapping {
 		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);
+		exchange.getAttributes().put(URI_TEMPLATE_VARIABLES_ATTRIBUTE, matchInfo.getUriVariables());
 
 		return handler;
 	}

spring-webflux/src/test/java/org/springframework/web/reactive/handler/SimpleUrlHandlerMappingTests.java

@@ -17,6 +17,8 @@
 package org.springframework.web.reactive.handler;
 
 import java.net.URI;
+import java.util.Collections;
+import java.util.Map;
 
 import org.junit.jupiter.api.Test;
 
@@ -115,6 +117,19 @@ public class SimpleUrlHandlerMappingTests {
 		}
 	}
 
+	@Test
+	void uriTemplateVariables() {
+		Object handler = new Object();
+		SimpleUrlHandlerMapping mapping = new SimpleUrlHandlerMapping();
+		mapping.registerHandlers(Collections.singletonMap("/foo/{bar}/baz", handler));
+
+		ServerWebExchange exchange = MockServerWebExchange.from(MockServerHttpRequest.get("/foo/123/baz").build());
+		Object expected = mapping.getHandler(exchange).block();
+		assertThat(expected).isSameAs(handler);
+
+		Map<String, String> vars = exchange.getAttribute(HandlerMapping.URI_TEMPLATE_VARIABLES_ATTRIBUTE);
+		assertThat(vars).isNotNull().containsEntry("bar", "123");
+	}
 
 	@Configuration
 	static class WebConfig {