Non-blocking HandlerMapping chain

spring-web-reactive/src/main/java/org/springframework/web/reactive/DispatcherHandler.java

@@ -19,6 +19,7 @@ package org.springframework.web.reactive;
 import java.util.ArrayList;
 import java.util.List;
 import java.util.Map;
+import java.util.stream.Collectors;
 
 import org.apache.commons.logging.Log;
 import org.apache.commons.logging.LogFactory;
@@ -30,7 +31,6 @@ import org.springframework.beans.factory.BeanFactoryUtils;
 import org.springframework.context.ApplicationContext;
 import org.springframework.context.ApplicationContextAware;
 import org.springframework.core.annotation.AnnotationAwareOrderComparator;
-import org.springframework.http.HttpStatus;
 import org.springframework.http.server.ReactiveHttpHandler;
 import org.springframework.http.server.ReactiveServerHttpRequest;
 import org.springframework.http.server.ReactiveServerHttpResponse;
@@ -76,6 +76,7 @@ public class DispatcherHandler implements ReactiveHttpHandler, ApplicationContex
 				context, HandlerMapping.class, true, false);
 
 		this.handlerMappings = new ArrayList<>(mappingBeans.values());
+		this.handlerMappings.add(new NotFoundHandlerMapping());
 		AnnotationAwareOrderComparator.sort(this.handlerMappings);
 
 		Map<String, HandlerAdapter> adapterBeans = BeanFactoryUtils.beansOfTypeIncludingAncestors(
@@ -98,13 +99,9 @@ public class DispatcherHandler implements ReactiveHttpHandler, ApplicationContex
 			logger.debug("Processing " + request.getMethod() + " request for [" + request.getURI() + "]");
 		}
 
-		Publisher<Object> handlerPublisher = getHandler(request);
-		if (handlerPublisher == null) {
-			// No exception handling mechanism yet
-			response.setStatusCode(HttpStatus.NOT_FOUND);
-			response.writeHeaders();
-			return Publishers.empty();
-		}
+		Publisher<HandlerMapping> mappings = Publishers.from(this.handlerMappings);
+		Publisher<Object> handlerPublisher = Publishers.concatMap(mappings, m -> m.getHandler(request));
+		handlerPublisher = first(handlerPublisher);
 
 		Publisher<HandlerResult> resultPublisher = Publishers.concatMap(handlerPublisher, handler -> {
 			HandlerAdapter handlerAdapter = getHandlerAdapter(handler);
@@ -117,16 +114,6 @@ public class DispatcherHandler implements ReactiveHttpHandler, ApplicationContex
 		});
 	}
 
-	protected Publisher<Object> getHandler(ReactiveServerHttpRequest request) {
-		for (HandlerMapping handlerMapping : this.handlerMappings) {
-			Publisher<Object> handlerPublisher = handlerMapping.getHandler(request);
-			if (handlerPublisher != null) {
-				return handlerPublisher;
-			}
-		}
-		return null;
-	}
-
 	protected HandlerAdapter getHandlerAdapter(Object handler) {
 		for (HandlerAdapter handlerAdapter : this.handlerAdapters) {
 			if (handlerAdapter.supports(handler)) {
@@ -145,4 +132,21 @@ public class DispatcherHandler implements ReactiveHttpHandler, ApplicationContex
 		throw new IllegalStateException("No HandlerResultHandler: " + handlerResult.getValue());
 	}
 
-}
+
+	private static <E> Publisher<E> first(Publisher<E> source) {
+		return Publishers.lift(source, (e, subscriber) -> {
+			subscriber.onNext(e);
+			subscriber.onComplete();
+		});
+	}
+
+	private static class NotFoundHandlerMapping implements HandlerMapping {
+
+		@Override
+		public Publisher<Object> getHandler(ReactiveServerHttpRequest request) {
+			return Publishers.error(new HandlerNotFoundException(request.getMethod(),
+					request.getURI().getPath(), request.getHeaders()));
+		}
+	}
+
+}

spring-web-reactive/src/main/java/org/springframework/web/reactive/HandlerNotFoundException.java

@@ -0,0 +1,59 @@
+/*
+ * Copyright 2002-2015 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
+ *
+ *      http://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.web.reactive;
+
+import org.springframework.core.NestedRuntimeException;
+import org.springframework.http.HttpHeaders;
+import org.springframework.http.HttpMethod;
+
+/**
+ * @author Rossen Stoyanchev
+ */
+public class HandlerNotFoundException extends NestedRuntimeException {
+
+	private final HttpMethod method;
+
+	private final String requestURL;
+
+	private final HttpHeaders headers;
+
+
+	/**
+	 * Constructor for NoHandlerFoundException.
+	 * @param method the HTTP method
+	 * @param requestURL the HTTP request URL
+	 * @param headers the HTTP request headers
+	 */
+	public HandlerNotFoundException(HttpMethod method, String requestURL, HttpHeaders headers) {
+		super("No handler found for " + method + " " + requestURL);
+		this.method = method;
+		this.requestURL = requestURL;
+		this.headers = headers;
+	}
+
+
+	public HttpMethod getMethod() {
+		return this.method;
+	}
+
+	public String getRequestURL() {
+		return this.requestURL;
+	}
+
+	public HttpHeaders getHeaders() {
+		return this.headers;
+	}
+}

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

@@ -21,6 +21,7 @@ import java.util.Map;
 
 import org.reactivestreams.Publisher;
 import reactor.Publishers;
+import reactor.core.publisher.PublisherFactory;
 
 import org.springframework.http.server.ReactiveServerHttpRequest;
 import org.springframework.web.reactive.HandlerMapping;
@@ -43,9 +44,14 @@ public class SimpleUrlHandlerMapping implements HandlerMapping {
 
 	@Override
 	public Publisher<Object> getHandler(ReactiveServerHttpRequest request) {
-		String path = request.getURI().getPath();
-		Object handler = this.handlerMap.get(path);
-		return (handler != null ? Publishers.just(handler) : null);
+		return PublisherFactory.create(subscriber -> {
+			String path = request.getURI().getPath();
+			Object handler = this.handlerMap.get(path);
+			if (handler != null) {
+				subscriber.onNext(handler);
+			}
+			subscriber.onComplete();
+		});
 	}
 
 }

spring-web-reactive/src/main/java/org/springframework/web/reactive/method/annotation/RequestMappingHandlerMapping.java

@@ -28,19 +28,19 @@ import java.util.TreeSet;
 import org.apache.commons.logging.Log;
 import org.apache.commons.logging.LogFactory;
 import org.reactivestreams.Publisher;
-import reactor.Publishers;
+import reactor.core.publisher.PublisherFactory;
 
 import org.springframework.beans.factory.InitializingBean;
 import org.springframework.context.ApplicationContext;
 import org.springframework.context.ApplicationContextAware;
 import org.springframework.core.annotation.AnnotationUtils;
 import org.springframework.http.server.ReactiveServerHttpRequest;
-import org.springframework.web.reactive.HandlerMapping;
 import org.springframework.stereotype.Controller;
 import org.springframework.web.bind.annotation.RequestMapping;
 import org.springframework.web.bind.annotation.RequestMethod;
 import org.springframework.web.method.HandlerMethod;
 import org.springframework.web.method.HandlerMethodSelector;
+import org.springframework.web.reactive.HandlerMapping;
 
 
 /**
@@ -95,18 +95,21 @@ public class RequestMappingHandlerMapping implements HandlerMapping,
 
 	@Override
 	public Publisher<Object> getHandler(ReactiveServerHttpRequest request) {
-		for (Map.Entry<RequestMappingInfo, HandlerMethod> entry : this.methodMap.entrySet()) {
-			RequestMappingInfo info = entry.getKey();
-			if (info.matchesRequest(request)) {
-				HandlerMethod handlerMethod = entry.getValue();
-				if (logger.isDebugEnabled()) {
-					logger.debug("Mapped " + request.getMethod() + " " +
-							request.getURI().getPath() + " to [" + handlerMethod + "]");
+		return PublisherFactory.create(subscriber -> {
+			for (Map.Entry<RequestMappingInfo, HandlerMethod> entry : this.methodMap.entrySet()) {
+				RequestMappingInfo info = entry.getKey();
+				if (info.matchesRequest(request)) {
+					HandlerMethod handlerMethod = entry.getValue();
+					if (logger.isDebugEnabled()) {
+						logger.debug("Mapped " + request.getMethod() + " " +
+								request.getURI().getPath() + " to [" + handlerMethod + "]");
+					}
+					subscriber.onNext(handlerMethod);
+					break;
 				}
-				return Publishers.just(handlerMethod);
 			}
-		}
-		return null;
+			subscriber.onComplete();
+		});
 	}
 
 

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

@@ -21,6 +21,7 @@ import java.nio.charset.Charset;
 import java.util.HashMap;
 import java.util.Map;
 
+import org.junit.Ignore;
 import org.junit.Test;
 import org.reactivestreams.Publisher;
 import reactor.io.buffer.Buffer;
@@ -31,11 +32,14 @@ import org.springframework.http.RequestEntity;
 import org.springframework.http.ResponseEntity;
 import org.springframework.http.server.ReactiveServerHttpRequest;
 import org.springframework.http.server.ReactiveServerHttpResponse;
+import org.springframework.web.client.HttpClientErrorException;
+import org.springframework.web.client.RestClientException;
 import org.springframework.web.reactive.DispatcherHandler;
 import org.springframework.http.server.AbstractHttpHandlerIntegrationTests;
 import org.springframework.http.server.ReactiveHttpHandler;
 import org.springframework.web.client.RestTemplate;
 import org.springframework.web.context.support.StaticWebApplicationContext;
+import org.springframework.web.reactive.method.annotation.RequestMappingHandlerMapping;
 
 import static org.junit.Assert.assertArrayEquals;
 import static org.junit.Assert.assertEquals;
@@ -89,6 +93,24 @@ public class SimpleUrlHandlerMappingIntegrationTests extends AbstractHttpHandler
 		assertArrayEquals("bar".getBytes(UTF_8), response.getBody());
 	}
 
+	// TODO: remove @Ignore after 404 default handling
+
+	@Test
+	@Ignore
+	public void testNotFound() throws Exception {
+
+		RestTemplate restTemplate = new RestTemplate();
+
+		URI url = new URI("http://localhost:" + port + "/oops");
+		RequestEntity<Void> request = RequestEntity.get(url).build();
+		try {
+			restTemplate.exchange(request, byte[].class);
+		}
+		catch (HttpClientErrorException ex) {
+			assertEquals(HttpStatus.NOT_FOUND, ex.getStatusCode());
+		}
+	}
+
 
 	private static class TestHandlerMapping extends SimpleUrlHandlerMapping {