Set BEST_MATCHING_HANDLER_ATTRIBUTE in WebFlux.fn

SPR-17367

spring-webflux/src/main/java/org/springframework/web/reactive/function/server/support/RouterFunctionMapping.java

@@ -18,6 +18,7 @@ package org.springframework.web.reactive.function.server.support;
 
 import java.util.Collections;
 import java.util.List;
+import java.util.Map;
 import java.util.stream.Collectors;
 
 import reactor.core.publisher.Mono;
@@ -27,6 +28,7 @@ import org.springframework.http.codec.HttpMessageReader;
 import org.springframework.http.codec.ServerCodecConfigurer;
 import org.springframework.lang.Nullable;
 import org.springframework.util.CollectionUtils;
+import org.springframework.web.reactive.function.server.HandlerFunction;
 import org.springframework.web.reactive.function.server.RouterFunction;
 import org.springframework.web.reactive.function.server.RouterFunctions;
 import org.springframework.web.reactive.function.server.ServerRequest;
@@ -142,12 +144,32 @@ public class RouterFunctionMapping extends AbstractHandlerMapping implements Ini
 	protected Mono<?> getHandlerInternal(ServerWebExchange exchange) {
 		if (this.routerFunction != null) {
 			ServerRequest request = ServerRequest.create(exchange, this.messageReaders);
-			exchange.getAttributes().put(RouterFunctions.REQUEST_ATTRIBUTE, request);
-			return this.routerFunction.route(request);
+			return this.routerFunction.route(request)
+					.doOnNext(handler -> setAttributes(exchange.getAttributes(), request, handler));
 		}
 		else {
 			return Mono.empty();
 		}
 	}
 
+	@SuppressWarnings("unchecked")
+	private void setAttributes(Map<String, Object> attributes, ServerRequest serverRequest,
+			HandlerFunction<?> handlerFunction) {
+
+		attributes.put(RouterFunctions.REQUEST_ATTRIBUTE, serverRequest);
+		attributes.put(BEST_MATCHING_HANDLER_ATTRIBUTE, handlerFunction);
+
+		String matchingPattern =
+				(String) attributes.get(RouterFunctions.MATCHING_PATTERN_ATTRIBUTE);
+		if (matchingPattern != null) {
+			attributes.put(BEST_MATCHING_PATTERN_ATTRIBUTE, matchingPattern);
+		}
+		Map<String, String> uriVariables =
+				(Map<String, String>) attributes
+						.get(RouterFunctions.URI_TEMPLATE_VARIABLES_ATTRIBUTE);
+		if (uriVariables != null) {
+			attributes.put(URI_TEMPLATE_VARIABLES_ATTRIBUTE, uriVariables);
+		}
+	}
+
 }