Support HTTP OPTIONS

Issue: SPR-13130

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

@@ -347,6 +347,7 @@ public class DispatcherServlet extends FrameworkServlet {
 	 */
 	public DispatcherServlet() {
 		super();
+		this.setDispatchOptionsRequest(true);
 	}
 
 	/**
@@ -390,6 +391,7 @@ public class DispatcherServlet extends FrameworkServlet {
 	 */
 	public DispatcherServlet(WebApplicationContext webApplicationContext) {
 		super(webApplicationContext);
+		this.setDispatchOptionsRequest(true);
 	}
 
 	/**

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

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2015 the original author or authors.
+ * Copyright 2002-2016 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.
@@ -428,9 +428,11 @@ public abstract class FrameworkServlet extends HttpServletBean implements Applic
 	/**
 	 * Set whether this servlet should dispatch an HTTP OPTIONS request to
 	 * the {@link #doService} method.
-	 * <p>Default is "false", applying {@link javax.servlet.http.HttpServlet}'s
-	 * default behavior (i.e. enumerating all standard HTTP request methods
-	 * as a response to the OPTIONS request).
+	 * <p>Default in the {@code FrameworkServlet} is "false", applying
+	 * {@link javax.servlet.http.HttpServlet}'s default behavior (i.e.enumerating
+	 * all standard HTTP request methods as a response to the OPTIONS request).
+	 * Note however that as of 4.3 the {@code DispatcherServlet} sets this
+	 * property to "true" by default due to its built-in support for OPTIONS.
 	 * <p>Turn this flag on if you prefer OPTIONS requests to go through the
 	 * regular dispatching chain, just like other HTTP requests. This usually
 	 * means that your controllers will receive those requests; make sure

spring-webmvc/src/main/java/org/springframework/web/servlet/mvc/annotation/ServletAnnotationMappingUtils.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2015 the original author or authors.
+ * Copyright 2002-2016 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.
@@ -30,6 +30,7 @@ import org.springframework.web.util.WebUtils;
  *
  * @author Juergen Hoeller
  * @author Arjen Poutsma
+ * @author Rossen Stoyanchev
  * @since 2.5.2
  * @deprecated as of Spring 3.2, together with {@link DefaultAnnotationHandlerMapping},
  * {@link AnnotationMethodHandlerAdapter}, and {@link AnnotationMethodHandlerExceptionResolver}.
@@ -43,11 +44,12 @@ abstract class ServletAnnotationMappingUtils {
 	 * @param request the current HTTP request to check
 	 */
 	public static boolean checkRequestMethod(RequestMethod[] methods, HttpServletRequest request) {
-		if (ObjectUtils.isEmpty(methods)) {
+		String inputMethod = request.getMethod();
+		if (ObjectUtils.isEmpty(methods) && !RequestMethod.OPTIONS.name().equals(inputMethod)) {
 			return true;
 		}
 		for (RequestMethod method : methods) {
-			if (method.name().equals(request.getMethod())) {
+			if (method.name().equals(inputMethod)) {
 				return true;
 			}
 		}

spring-webmvc/src/main/java/org/springframework/web/servlet/mvc/condition/RequestMethodsRequestCondition.java

@@ -99,27 +99,24 @@ public final class RequestMethodsRequestCondition extends AbstractRequestConditi
 	 */
 	@Override
 	public RequestMethodsRequestCondition getMatchingCondition(HttpServletRequest request) {
-		if (this.methods.isEmpty()) {
-			return this;
-		}
 		RequestMethod requestMethod = getRequestMethod(request);
-		if (requestMethod != null) {
-			for (RequestMethod method : this.methods) {
-				if (method.equals(requestMethod)) {
-					return new RequestMethodsRequestCondition(method);
-				}
-			}
-			if (isHeadRequest(requestMethod) && getMethods().contains(RequestMethod.GET)) {
-				return HEAD_CONDITION;
+		if (requestMethod == null) {
+			return null;
+		}
+		if (this.methods.isEmpty()) {
+			return (RequestMethod.OPTIONS.equals(requestMethod) ? null : this);
+		}
+		for (RequestMethod method : this.methods) {
+			if (method.equals(requestMethod)) {
+				return new RequestMethodsRequestCondition(method);
 			}
 		}
+		if (RequestMethod.HEAD.equals(requestMethod) && getMethods().contains(RequestMethod.GET)) {
+			return HEAD_CONDITION;
+		}
 		return null;
 	}
 
-	private boolean isHeadRequest(RequestMethod requestMethod) {
-		return (requestMethod != null && RequestMethod.HEAD.equals(requestMethod));
-	}
-
 	private RequestMethod getRequestMethod(HttpServletRequest request) {
 		try {
 			return RequestMethod.valueOf(request.getMethod());

spring-webmvc/src/main/java/org/springframework/web/servlet/mvc/method/RequestMappingInfoHandlerMapping.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2015 the original author or authors.
+ * Copyright 2002-2016 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.
@@ -16,6 +16,7 @@
 
 package org.springframework.web.servlet.mvc.method;
 
+import java.lang.reflect.Method;
 import java.util.ArrayList;
 import java.util.Collections;
 import java.util.Comparator;
@@ -29,6 +30,8 @@ import java.util.Set;
 import javax.servlet.ServletException;
 import javax.servlet.http.HttpServletRequest;
 
+import org.springframework.http.HttpHeaders;
+import org.springframework.http.HttpMethod;
 import org.springframework.http.InvalidMediaTypeException;
 import org.springframework.http.MediaType;
 import org.springframework.util.CollectionUtils;
@@ -56,6 +59,19 @@ import org.springframework.web.util.WebUtils;
  */
 public abstract class RequestMappingInfoHandlerMapping extends AbstractHandlerMethodMapping<RequestMappingInfo> {
 
+	private static final Method HTTP_OPTIONS_HANDLE_METHOD;
+
+	static {
+		try {
+			HTTP_OPTIONS_HANDLE_METHOD = HttpOptionsHandler.class.getMethod("handle");
+		}
+		catch (NoSuchMethodException ex) {
+			// Should never happen
+			throw new IllegalStateException("No handler for HTTP OPTIONS", ex);
+		}
+	}
+
+
 	protected RequestMappingInfoHandlerMapping() {
 		setHandlerMethodMappingNamingStrategy(new RequestMappingInfoHandlerMethodMappingNamingStrategy());
 	}
@@ -200,8 +216,14 @@ public abstract class RequestMappingInfoHandlerMapping extends AbstractHandlerMe
 		if (patternMatches.isEmpty()) {
 			return null;
 		}
-		else if (patternAndMethodMatches.isEmpty() && !allowedMethods.isEmpty()) {
-			throw new HttpRequestMethodNotSupportedException(request.getMethod(), allowedMethods);
+		else if (patternAndMethodMatches.isEmpty()) {
+			if (HttpMethod.OPTIONS.matches(request.getMethod())) {
+				HttpOptionsHandler handler = new HttpOptionsHandler(allowedMethods);
+				return new HandlerMethod(handler, HTTP_OPTIONS_HANDLE_METHOD);
+			}
+			else if (!allowedMethods.isEmpty()) {
+				throw new HttpRequestMethodNotSupportedException(request.getMethod(), allowedMethods);
+			}
 		}
 
 		Set<MediaType> consumableMediaTypes;
@@ -279,4 +301,40 @@ public abstract class RequestMappingInfoHandlerMapping extends AbstractHandlerMe
 		return result;
 	}
 
+
+	/**
+	 * Default handler for HTTP OPTIONS.
+	 */
+	private static class HttpOptionsHandler {
+
+		private final HttpHeaders headers = new HttpHeaders();
+
+
+		public HttpOptionsHandler(Set<String> declaredMethods) {
+			this.headers.setAllow(initAllowedHttpMethods(declaredMethods));
+		}
+
+		private static Set<HttpMethod> initAllowedHttpMethods(Set<String> declaredMethods) {
+			Set<HttpMethod> result = new LinkedHashSet<HttpMethod>(declaredMethods.size());
+			if (declaredMethods.isEmpty()) {
+				result.add(HttpMethod.GET);
+				result.add(HttpMethod.HEAD);
+			}
+			else {
+				boolean hasHead = declaredMethods.contains("HEAD");
+				for (String method : declaredMethods) {
+					result.add(HttpMethod.valueOf(method));
+					if (!hasHead && "GET".equals(method)) {
+						result.add(HttpMethod.HEAD);
+					}
+				}
+			}
+			return result;
+		}
+
+		public HttpHeaders handle() {
+			return this.headers;
+		}
+	}
+
 }

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

@@ -37,6 +37,7 @@ import org.springframework.beans.factory.InitializingBean;
 import org.springframework.core.io.ClassPathResource;
 import org.springframework.core.io.Resource;
 import org.springframework.http.HttpHeaders;
+import org.springframework.http.HttpMethod;
 import org.springframework.http.HttpRange;
 import org.springframework.http.MediaType;
 import org.springframework.http.server.ServletServerHttpRequest;
@@ -111,7 +112,7 @@ public class ResourceHttpRequestHandler extends WebContentGenerator
 
 
 	public ResourceHttpRequestHandler() {
-		super(METHOD_GET, METHOD_HEAD);
+		super(HttpMethod.GET.name(), HttpMethod.HEAD.name(), HttpMethod.OPTIONS.name());
 		this.resourceResolvers.add(new PathResourceResolver());
 	}
 
@@ -236,6 +237,11 @@ public class ResourceHttpRequestHandler extends WebContentGenerator
 			return;
 		}
 
+		if (HttpMethod.OPTIONS.matches(request.getMethod())) {
+			response.setHeader("Allow", "GET,HEAD");
+			return;
+		}
+
 		// Header phase
 		if (new ServletWebRequest(request, response).checkNotModified(resource.lastModified())) {
 			logger.trace("Resource not modified - returning 304");