Use ContentNegotiationManager for static resources

The ResourceHttpRequestHandler now relies on the conifgured
ContentNegotiationManager to determine the content type for resource
requests rather than implementing that internally.

First we check against the matched resource based on the resource file
extension. Then we expand the check against the request with any
configured content negotiation strategy.

Issue: SPR-13658

spring-web/src/main/java/org/springframework/web/accept/ContentNegotiationManager.java

 /*
- * 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.
@@ -96,6 +96,22 @@ public class ContentNegotiationManager implements ContentNegotiationStrategy,
 		return this.strategies;
 	}
 
+	/**
+	 * Find a {@code ContentNegotiationStrategy} of the given type.
+	 * @param strategyType the strategy type
+	 * @return the first matching strategy or {@code null}.
+	 * @since 4.3
+	 */
+	@SuppressWarnings("unchecked")
+	public <T extends ContentNegotiationStrategy> T getStrategy(Class<T> strategyType) {
+		for (ContentNegotiationStrategy strategy : getStrategies()) {
+			if (strategyType.isInstance(strategy)) {
+				return (T) strategy;
+			}
+		}
+		return null;
+	}
+
 	/**
 	 * Register more {@code MediaTypeFileExtensionResolver} instances in addition
 	 * to those detected at construction.

spring-web/src/main/java/org/springframework/web/accept/PathExtensionContentNegotiationStrategy.java

 /*
- * 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.apache.commons.logging.LogFactory;
 import org.springframework.core.io.ClassPathResource;
 import org.springframework.core.io.Resource;
 import org.springframework.http.MediaType;
+import org.springframework.util.Assert;
 import org.springframework.util.ClassUtils;
 import org.springframework.util.StringUtils;
 import org.springframework.web.HttpMediaTypeNotAcceptableException;
@@ -135,6 +136,32 @@ public class PathExtensionContentNegotiationStrategy
 		throw new HttpMediaTypeNotAcceptableException(getAllMediaTypes());
 	}
 
+	/**
+	 * A public method exposing the knowledge of the path extension strategy to
+	 * resolve file extensions to a MediaType in this case for a given
+	 * {@link Resource}. The method first looks up any explicitly registered
+	 * file extensions first and then falls back on JAF if available.
+	 * @param resource the resource to look up
+	 * @return the MediaType for the extension or {@code null}.
+	 * @since 4.3
+	 */
+	public MediaType getMediaTypeForResource(Resource resource) {
+		Assert.notNull(resource);
+		MediaType mediaType = null;
+		String filename = resource.getFilename();
+		String extension = StringUtils.getFilenameExtension(filename);
+		if (extension != null) {
+			mediaType = lookupMediaType(extension);
+		}
+		if (mediaType == null && JAF_PRESENT) {
+			mediaType = JafMediaTypeFactory.getMediaType(filename);
+		}
+		if (MediaType.APPLICATION_OCTET_STREAM.equals(mediaType)) {
+			mediaType = null;
+		}
+		return mediaType;
+	}
+
 
 	/**
 	 * Inner class to avoid hard-coded dependency on JAF.

spring-web/src/main/java/org/springframework/web/accept/ServletPathExtensionContentNegotiationStrategy.java

 /*
- * 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.
@@ -18,6 +18,7 @@ package org.springframework.web.accept;
 import java.util.Map;
 import javax.servlet.ServletContext;
 
+import org.springframework.core.io.Resource;
 import org.springframework.http.MediaType;
 import org.springframework.util.Assert;
 import org.springframework.util.StringUtils;
@@ -82,4 +83,26 @@ public class ServletPathExtensionContentNegotiationStrategy
 		return mediaType;
 	}
 
+	/**
+	 * Extends the base class
+	 * {@link PathExtensionContentNegotiationStrategy#getMediaTypeForResource}
+	 * with the ability to also look up through the ServletContext.
+	 * @param resource the resource to look up
+	 * @return the MediaType for the extension or {@code null}.
+	 * @since 4.3
+	 */
+	public MediaType getMediaTypeForResource(Resource resource) {
+		MediaType mediaType = super.getMediaTypeForResource(resource);
+		if (mediaType == null) {
+			String mimeType = this.servletContext.getMimeType(resource.getFilename());
+			if (StringUtils.hasText(mimeType)) {
+				mediaType = MediaType.parseMediaType(mimeType);
+			}
+		}
+		if (MediaType.APPLICATION_OCTET_STREAM.equals(mediaType)) {
+			mediaType = null;
+		}
+		return mediaType;
+	}
+
 }

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

@@ -43,7 +43,6 @@ import org.springframework.util.CollectionUtils;
 import org.springframework.util.StringUtils;
 import org.springframework.web.HttpMediaTypeNotAcceptableException;
 import org.springframework.web.accept.ContentNegotiationManager;
-import org.springframework.web.accept.ContentNegotiationStrategy;
 import org.springframework.web.accept.PathExtensionContentNegotiationStrategy;
 import org.springframework.web.context.request.NativeWebRequest;
 import org.springframework.web.context.request.ServletWebRequest;
@@ -122,12 +121,9 @@ public abstract class AbstractMessageConverterMethodProcessor extends AbstractMe
 	}
 
 	private static PathExtensionContentNegotiationStrategy initPathStrategy(ContentNegotiationManager manager) {
-		for (ContentNegotiationStrategy strategy : manager.getStrategies()) {
-			if (strategy instanceof PathExtensionContentNegotiationStrategy) {
-				return (PathExtensionContentNegotiationStrategy) strategy;
-			}
-		}
-		return new PathExtensionContentNegotiationStrategy();
+		Class<PathExtensionContentNegotiationStrategy> clazz = PathExtensionContentNegotiationStrategy.class;
+		PathExtensionContentNegotiationStrategy strategy = manager.getStrategy(clazz);
+		return (strategy != null ? strategy : new PathExtensionContentNegotiationStrategy());
 	}
 
 

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

@@ -23,8 +23,6 @@ import java.io.OutputStream;
 import java.net.URLDecoder;
 import java.util.ArrayList;
 import java.util.List;
-import javax.activation.FileTypeMap;
-import javax.activation.MimetypesFileTypeMap;
 import javax.servlet.ServletException;
 import javax.servlet.ServletOutputStream;
 import javax.servlet.http.HttpServletRequest;
@@ -34,7 +32,6 @@ import org.apache.commons.logging.Log;
 import org.apache.commons.logging.LogFactory;
 
 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;
@@ -49,7 +46,11 @@ import org.springframework.util.ObjectUtils;
 import org.springframework.util.ResourceUtils;
 import org.springframework.util.StreamUtils;
 import org.springframework.util.StringUtils;
+import org.springframework.web.HttpMediaTypeNotAcceptableException;
 import org.springframework.web.HttpRequestHandler;
+import org.springframework.web.accept.ContentNegotiationManager;
+import org.springframework.web.accept.ContentNegotiationManagerFactoryBean;
+import org.springframework.web.accept.PathExtensionContentNegotiationStrategy;
 import org.springframework.web.context.request.ServletWebRequest;
 import org.springframework.web.cors.CorsConfiguration;
 import org.springframework.web.cors.CorsConfigurationSource;
@@ -103,6 +104,8 @@ public class ResourceHttpRequestHandler extends WebContentGenerator
 
 	private final List<ResourceTransformer> resourceTransformers = new ArrayList<ResourceTransformer>(4);
 
+	private ContentNegotiationManager contentNegotiationManager;
+
 	private CorsConfiguration corsConfiguration;
 
 
@@ -162,6 +165,28 @@ public class ResourceHttpRequestHandler extends WebContentGenerator
 		return this.resourceTransformers;
 	}
 
+	/**
+	 * Configure a {@code ContentNegotiationManager} to determine the media types
+	 * for resources being served. If the manager contains a path
+	 * extension strategy it will be used to look up the file extension
+	 * of resources being served via
+	 * {@link PathExtensionContentNegotiationStrategy#getMediaTypeForResource
+	 * getMediaTypeForResource}. If that fails the check is then expanded
+	 * to use any configured content negotiation strategy against the request.
+	 * <p>By default a {@link ContentNegotiationManagerFactoryBean} with default
+	 * settings is used to create the manager. See the Javadoc of
+	 * {@code ContentNegotiationManagerFactoryBean} for details
+	 * @param contentNegotiationManager the manager to use
+	 * @since 4.3
+	 */
+	public void setContentNegotiationManager(ContentNegotiationManager contentNegotiationManager) {
+		this.contentNegotiationManager = contentNegotiationManager;
+	}
+
+	public ContentNegotiationManager getContentNegotiationManager() {
+		return this.contentNegotiationManager;
+	}
+
 	/**
 	 * Specify the CORS configuration for resources served by this handler.
 	 * <p>By default this is not set in which allows cross-origin requests.
@@ -186,6 +211,10 @@ public class ResourceHttpRequestHandler extends WebContentGenerator
 			this.resourceResolvers.add(new PathResourceResolver());
 		}
 		initAllowedLocations();
+
+		if (this.contentNegotiationManager == null) {
+			this.contentNegotiationManager = initContentNegotiationManager();
+		}
 	}
 
 	/**
@@ -208,6 +237,17 @@ public class ResourceHttpRequestHandler extends WebContentGenerator
 		}
 	}
 
+	/**
+	 * Create the {@code ContentNegotiationManager} to use to resolve the
+	 * {@link MediaType} for requests. This implementation delegates to
+	 * {@link ContentNegotiationManagerFactoryBean} with default settings.
+	 */
+	protected ContentNegotiationManager initContentNegotiationManager() {
+		ContentNegotiationManagerFactoryBean factory = new ContentNegotiationManagerFactoryBean();
+		factory.afterPropertiesSet();
+		return factory.getObject();
+	}
+
 
 	/**
 	 * Processes a resource request.
@@ -250,8 +290,8 @@ public class ResourceHttpRequestHandler extends WebContentGenerator
 		// Apply cache settings, if any
 		prepareResponse(response);
 
-		// Check the resource's media type
-		MediaType mediaType = getMediaType(resource);
+		// Check the media type for the resource
+		MediaType mediaType = getMediaType(request, resource);
 		if (mediaType != null) {
 			if (logger.isTraceEnabled()) {
 				logger.trace("Determined media type '" + mediaType + "' for " + resource);
@@ -391,25 +431,56 @@ public class ResourceHttpRequestHandler extends WebContentGenerator
 	}
 
 	/**
-	 * Determine an appropriate media type for the given resource.
+	 * Determine the media type for the given request and the resource matched
+	 * to it. This implementation first tries to determine the MediaType based
+	 * strictly on the file extension of the Resource via
+	 * {@link PathExtensionContentNegotiationStrategy#getMediaTypeForResource}
+	 * and then expands to check against the request via
+	 * {@link ContentNegotiationManager#resolveMediaTypes}.
+	 * @param request the current request
 	 * @param resource the resource to check
 	 * @return the corresponding media type, or {@code null} if none found
 	 */
-	protected MediaType getMediaType(Resource resource) {
-		MediaType mediaType = null;
-		String mimeType = getServletContext().getMimeType(resource.getFilename());
-		if (StringUtils.hasText(mimeType)) {
-			mediaType = MediaType.parseMediaType(mimeType);
-		}
-		if (jafPresent && (mediaType == null || MediaType.APPLICATION_OCTET_STREAM.equals(mediaType))) {
-			MediaType jafMediaType = ActivationMediaTypeFactory.getMediaType(resource.getFilename());
-			if (jafMediaType != null && !MediaType.APPLICATION_OCTET_STREAM.equals(jafMediaType)) {
-				mediaType = jafMediaType;
+	@SuppressWarnings("deprecation")
+	protected MediaType getMediaType(HttpServletRequest request, Resource resource) {
+
+		// For backwards compatibility
+		MediaType mediaType = getMediaType(resource);
+		if (mediaType != null) {
+			return mediaType;
+		}
+
+		Class<PathExtensionContentNegotiationStrategy> clazz = PathExtensionContentNegotiationStrategy.class;
+		PathExtensionContentNegotiationStrategy strategy = this.contentNegotiationManager.getStrategy(clazz);
+		if (strategy != null) {
+			mediaType = strategy.getMediaTypeForResource(resource);
+		}
+
+		if (mediaType == null) {
+			ServletWebRequest webRequest = new ServletWebRequest(request);
+			try {
+				getContentNegotiationManager().resolveMediaTypes(webRequest);
+			}
+			catch (HttpMediaTypeNotAcceptableException ex) {
+				// Ignore
 			}
 		}
+
 		return mediaType;
 	}
 
+	/**
+	 * Determine an appropriate media type for the given resource.
+	 * @param resource the resource to check
+	 * @return the corresponding media type, or {@code null} if none found
+	 * @deprecated as of 4.3 this method is deprecated; please override
+	 * {@link #getMediaType(HttpServletRequest, Resource)} instead.
+	 */
+	@Deprecated
+	protected MediaType getMediaType(Resource resource) {
+		return null;
+	}
+
 	/**
 	 * Set headers on the given servlet response.
 	 * Called for GET requests as well as HEAD requests.
@@ -575,48 +646,4 @@ public class ResourceHttpRequestHandler extends WebContentGenerator
 		return "ResourceHttpRequestHandler [locations=" + getLocations() + ", resolvers=" + getResourceResolvers() + "]";
 	}
 
-
-	/**
-	 * Inner class to avoid a hard-coded JAF dependency.
-	 */
-	private static class ActivationMediaTypeFactory {
-
-		private static final FileTypeMap fileTypeMap;
-
-		static {
-			fileTypeMap = loadFileTypeMapFromContextSupportModule();
-		}
-
-		private static FileTypeMap loadFileTypeMapFromContextSupportModule() {
-			// See if we can find the extended mime.types from the context-support module...
-			Resource mappingLocation = new ClassPathResource("org/springframework/mail/javamail/mime.types");
-			if (mappingLocation.exists()) {
-				InputStream inputStream = null;
-				try {
-					inputStream = mappingLocation.getInputStream();
-					return new MimetypesFileTypeMap(inputStream);
-				}
-				catch (IOException ex) {
-					// ignore
-				}
-				finally {
-					if (inputStream != null) {
-						try {
-							inputStream.close();
-						}
-						catch (IOException ex) {
-							// ignore
-						}
-					}
-				}
-			}
-			return FileTypeMap.getDefaultFileTypeMap();
-		}
-
-		public static MediaType getMediaType(String filename) {
-			String mediaType = fileTypeMap.getContentType(filename);
-			return (StringUtils.hasText(mediaType) ? MediaType.parseMediaType(mediaType) : null);
-		}
-	}
-
 }

spring-webmvc/src/test/java/org/springframework/web/servlet/resource/ResourceHttpRequestHandlerTests.java

@@ -42,11 +42,14 @@ import org.springframework.core.io.Resource;
 import org.springframework.core.io.UrlResource;
 import org.springframework.http.HttpMethod;
 import org.springframework.http.HttpStatus;
+import org.springframework.http.MediaType;
 import org.springframework.mock.web.test.MockHttpServletRequest;
 import org.springframework.mock.web.test.MockHttpServletResponse;
 import org.springframework.mock.web.test.MockServletContext;
 import org.springframework.util.StringUtils;
 import org.springframework.web.HttpRequestMethodNotSupportedException;
+import org.springframework.web.accept.ContentNegotiationManager;
+import org.springframework.web.accept.ContentNegotiationManagerFactoryBean;
 import org.springframework.web.servlet.HandlerMapping;
 
 /**
@@ -225,6 +228,26 @@ public class ResourceHttpRequestHandlerTests {
 		assertEquals("function foo() { console.log(\"hello world\"); }", this.response.getContentAsString());
 	}
 
+	@Test // SPR-13658
+	public void getResourceWithRegisteredMediaType() throws Exception {
+		ContentNegotiationManagerFactoryBean factory = new ContentNegotiationManagerFactoryBean();
+		factory.addMediaType("css", new MediaType("foo", "bar"));
+		factory.afterPropertiesSet();
+		ContentNegotiationManager manager = factory.getObject();
+
+		List<Resource> paths = Collections.singletonList(new ClassPathResource("test/", getClass()));
+		this.handler = new ResourceHttpRequestHandler();
+		this.handler.setLocations(paths);
+		this.handler.setContentNegotiationManager(manager);
+		this.handler.afterPropertiesSet();
+
+		this.request.setAttribute(HandlerMapping.PATH_WITHIN_HANDLER_MAPPING_ATTRIBUTE, "foo.css");
+		this.handler.handleRequest(this.request, this.response);
+
+		assertEquals("foo/bar", this.response.getContentType());
+		assertEquals("h1 { color:red; }", this.response.getContentAsString());
+	}
+
 	@Test
 	public void invalidPath() throws Exception {
 		for (HttpMethod method : HttpMethod.values()) {