ResourceWebHandler uses MediaTypeFactory directly

There is no need for ResourceWebHandler to go through the
PathExtensionContentTypeResolver when MediaTypeFactory makes it easy to
perform such lookups for a given Resource.

This does not support any extensions explicitly registered through a
WebFluxConfigurer but it would be easy enough to pass those into
ResourceWebHandler as a simple Map<String, MediaType>, should the need
arise.

Issue: SPR-15639

Author: rstoyanchev

spring-webflux/src/main/java/org/springframework/web/reactive/accept/PathExtensionContentTypeResolver.java

@@ -20,11 +20,9 @@
 import java.util.Map;
 import java.util.Optional;
 
-import org.springframework.core.io.Resource;
 import org.springframework.http.MediaType;
 import org.springframework.http.MediaTypeFactory;
 import org.springframework.lang.Nullable;
-import org.springframework.util.Assert;
 import org.springframework.util.StringUtils;
 import org.springframework.web.server.NotAcceptableStatusException;
 import org.springframework.web.server.ServerWebExchange;
@@ -104,26 +102,4 @@ protected MediaType handleNoMatch(String key) throws NotAcceptableStatusExceptio
 		throw new NotAcceptableStatusException(getAllMediaTypes());
 	}
 
-	/**
-	 * A public method exposing the knowledge of the path extension resolver to
-	 * determine the media type for a given {@link Resource}. First it checks
-	 * the explicitly registered mappings and then falls back on {@link MediaTypeFactory}.
-	 * @param resource the resource
-	 * @return the MediaType for the extension, or {@code null} if none determined
-	 */
-	@Nullable
-	public MediaType resolveMediaTypeForResource(Resource resource) {
-		Assert.notNull(resource, "Resource must not be null");
-		MediaType mediaType = null;
-		String filename = resource.getFilename();
-		String extension = StringUtils.getFilenameExtension(filename);
-		if (extension != null) {
-			mediaType = getMediaType(extension);
-		}
-		if (mediaType == null) {
-			mediaType = MediaTypeFactory.getMediaType(filename).orElse(null);
-		}
-		return mediaType;
-	}
-
 }

spring-webflux/src/main/java/org/springframework/web/reactive/config/ResourceHandlerRegistry.java

@@ -26,7 +26,6 @@
 import org.springframework.context.ApplicationContext;
 import org.springframework.lang.Nullable;
 import org.springframework.util.Assert;
-import org.springframework.web.reactive.accept.CompositeContentTypeResolver;
 import org.springframework.web.reactive.handler.AbstractHandlerMapping;
 import org.springframework.web.reactive.handler.SimpleUrlHandlerMapping;
 import org.springframework.web.reactive.resource.ResourceWebHandler;
@@ -56,8 +55,6 @@ public class ResourceHandlerRegistry {
 
 	private final ApplicationContext applicationContext;
 
-	private final CompositeContentTypeResolver contentTypeResolver;
-
 	private final List<ResourceHandlerRegistration> registrations = new ArrayList<>();
 
 	private int order = Integer.MAX_VALUE -1;
@@ -68,20 +65,9 @@ public class ResourceHandlerRegistry {
 	 * @param applicationContext the Spring application context
 	 */
 	public ResourceHandlerRegistry(ApplicationContext applicationContext) {
-		this(applicationContext, null);
-	}
-
-	/**
-	 * Create a new resource handler registry for the given application context.
-	 * @param applicationContext the Spring application context
-	 * @param contentTypeResolver the content type resolver to use
-	 */
-	public ResourceHandlerRegistry(ApplicationContext applicationContext,
-			@Nullable CompositeContentTypeResolver contentTypeResolver) {
 
 		Assert.notNull(applicationContext, "ApplicationContext is required");
 		this.applicationContext = applicationContext;
-		this.contentTypeResolver = contentTypeResolver;
 	}
 
 
@@ -133,23 +119,19 @@ protected AbstractHandlerMapping getHandlerMapping() {
 		if (this.registrations.isEmpty()) {
 			return null;
 		}
-
 		Map<String, WebHandler> urlMap = new LinkedHashMap<>();
 		for (ResourceHandlerRegistration registration : this.registrations) {
 			for (String pathPattern : registration.getPathPatterns()) {
 				ResourceWebHandler handler = registration.getRequestHandler();
-				handler.setContentTypeResolver(this.contentTypeResolver);
 				try {
 					handler.afterPropertiesSet();
-					handler.afterSingletonsInstantiated();
 				}
 				catch (Exception ex) {
 					throw new BeanInitializationException("Failed to init ResourceHttpRequestHandler", ex);
 				}
 				urlMap.put(pathPattern, handler);
 			}
 		}
-
 		SimpleUrlHandlerMapping handlerMapping = new SimpleUrlHandlerMapping();
 		handlerMapping.setOrder(this.order);
 		handlerMapping.setUrlMap(urlMap);

spring-webflux/src/main/java/org/springframework/web/reactive/config/WebFluxConfigurationSupport.java

@@ -235,8 +235,7 @@ protected RouterFunctionMapping createRouterFunctionMapping() {
 	 */
 	@Bean
 	public HandlerMapping resourceHandlerMapping() {
-		ResourceHandlerRegistry registry =
-				new ResourceHandlerRegistry(this.applicationContext, webFluxContentTypeResolver());
+		ResourceHandlerRegistry registry = new ResourceHandlerRegistry(this.applicationContext);
 		addResourceHandlers(registry);
 
 		AbstractHandlerMapping handlerMapping = registry.getHandlerMapping();

spring-webflux/src/main/java/org/springframework/web/reactive/resource/ResourceWebHandler.java

@@ -23,9 +23,7 @@
 import java.util.ArrayList;
 import java.util.Collections;
 import java.util.EnumSet;
-import java.util.HashMap;
 import java.util.List;
-import java.util.Map;
 import java.util.Optional;
 import java.util.Set;
 
@@ -35,14 +33,14 @@
 import reactor.core.publisher.Mono;
 
 import org.springframework.beans.factory.InitializingBean;
-import org.springframework.beans.factory.SmartInitializingSingleton;
 import org.springframework.core.ResolvableType;
 import org.springframework.core.io.Resource;
 import org.springframework.http.CacheControl;
 import org.springframework.http.HttpHeaders;
 import org.springframework.http.HttpMethod;
 import org.springframework.http.HttpStatus;
 import org.springframework.http.MediaType;
+import org.springframework.http.MediaTypeFactory;
 import org.springframework.http.codec.ResourceHttpMessageWriter;
 import org.springframework.lang.Nullable;
 import org.springframework.util.Assert;
@@ -51,8 +49,6 @@
 import org.springframework.util.ResourceUtils;
 import org.springframework.util.StringUtils;
 import org.springframework.web.reactive.HandlerMapping;
-import org.springframework.web.reactive.accept.CompositeContentTypeResolver;
-import org.springframework.web.reactive.accept.PathExtensionContentTypeResolver;
 import org.springframework.web.server.MethodNotAllowedException;
 import org.springframework.web.server.ServerWebExchange;
 import org.springframework.web.server.WebHandler;
@@ -85,7 +81,7 @@
  * @author Brian Clozel
  * @since 5.0
  */
-public class ResourceWebHandler implements WebHandler, InitializingBean, SmartInitializingSingleton {
+public class ResourceWebHandler implements WebHandler, InitializingBean {
 
 	/** Set of supported HTTP methods */
 	private static final Set<HttpMethod> SUPPORTED_METHODS = EnumSet.of(HttpMethod.GET, HttpMethod.HEAD);
@@ -103,10 +99,6 @@ public class ResourceWebHandler implements WebHandler, InitializingBean, SmartIn
 
 	private ResourceHttpMessageWriter resourceHttpMessageWriter;
 
-	private CompositeContentTypeResolver contentTypeResolver;
-
-	private PathExtensionContentTypeResolver pathExtensionResolver;
-
 
 	/**
 	 * Set the {@code List} of {@code Resource} paths to use as sources
@@ -197,23 +189,6 @@ public ResourceHttpMessageWriter getResourceHttpMessageWriter() {
 		return this.resourceHttpMessageWriter;
 	}
 
-	/**
-	 * Configure a {@link CompositeContentTypeResolver} to help determine the
-	 * media types for resources being served. If the manager contains a path
-	 * extension resolver it will be checked for registered file extension.
-	 * @param contentTypeResolver the resolver in use
-	 */
-	public void setContentTypeResolver(CompositeContentTypeResolver contentTypeResolver) {
-		this.contentTypeResolver = contentTypeResolver;
-	}
-
-	/**
-	 * Return the configured {@link CompositeContentTypeResolver}.
-	 */
-	@Nullable
-	public CompositeContentTypeResolver getContentTypeResolver() {
-		return this.contentTypeResolver;
-	}
 
 	@Override
 	public void afterPropertiesSet() throws Exception {
@@ -250,23 +225,6 @@ protected void initAllowedLocations() {
 		}
 	}
 
-	@Override
-	public void afterSingletonsInstantiated() {
-		this.pathExtensionResolver = initContentNegotiationStrategy();
-	}
-
-	protected PathExtensionContentTypeResolver initContentNegotiationStrategy() {
-		Map<String, MediaType> mediaTypes = null;
-		if (getContentTypeResolver() != null) {
-			PathExtensionContentTypeResolver strategy =
-					getContentTypeResolver().findResolver(PathExtensionContentTypeResolver.class);
-			if (strategy != null) {
-				mediaTypes = new HashMap<>(strategy.getMediaTypes());
-			}
-		}
-		return new PathExtensionContentTypeResolver(mediaTypes);
-	}
-
 
 	/**
 	 * Processes a resource request.
@@ -317,7 +275,7 @@ public Mono<Void> handle(ServerWebExchange exchange) {
 						}
 
 						// Check the media type for the resource
-						MediaType mediaType = getMediaType(exchange, resource);
+						MediaType mediaType = MediaTypeFactory.getMediaType(resource).orElse(null);
 						if (mediaType != null) {
 							if (logger.isTraceEnabled()) {
 								logger.trace("Determined media type '" + mediaType + "' for " + resource);
@@ -474,20 +432,6 @@ private ResourceTransformerChain createTransformerChain(ResourceResolverChain re
 		return new DefaultResourceTransformerChain(resolverChain, getResourceTransformers());
 	}
 
-	/**
-	 * Determine the media type for the given request and the resource matched
-	 * to it. This implementation tries to determine the MediaType based on the
-	 * file extension of the Resource via
-	 * {@link PathExtensionContentTypeResolver#resolveMediaTypeForResource(Resource)}.
-	 * @param exchange the current exchange
-	 * @param resource the resource to check
-	 * @return the corresponding media type, or {@code null} if none found
-	 */
-	@Nullable
-	protected MediaType getMediaType(ServerWebExchange exchange, Resource resource) {
-		return this.pathExtensionResolver.resolveMediaTypeForResource(resource);
-	}
-
 	/**
 	 * Set headers on the response. Called for both GET and HEAD requests.
 	 * @param exchange current exchange

spring-webflux/src/test/java/org/springframework/web/reactive/resource/ResourceWebHandlerTests.java

@@ -49,8 +49,6 @@
 import org.springframework.mock.http.server.reactive.test.MockServerWebExchange;
 import org.springframework.util.StringUtils;
 import org.springframework.web.reactive.HandlerMapping;
-import org.springframework.web.reactive.accept.CompositeContentTypeResolver;
-import org.springframework.web.reactive.accept.RequestedContentTypeResolverBuilder;
 import org.springframework.web.server.MethodNotAllowedException;
 import org.springframework.web.server.ServerWebExchange;
 
@@ -86,7 +84,6 @@ public void setup() throws Exception {
 		this.handler.setLocations(paths);
 		this.handler.setCacheControl(CacheControl.maxAge(3600, TimeUnit.SECONDS));
 		this.handler.afterPropertiesSet();
-		this.handler.afterSingletonsInstantiated();
 	}
 
 
@@ -159,7 +156,6 @@ public void getVersionedResource() throws Exception {
 		versionResolver.addFixedVersionStrategy("versionString", "/**");
 		this.handler.setResourceResolvers(Arrays.asList(versionResolver, new PathResourceResolver()));
 		this.handler.afterPropertiesSet();
-		this.handler.afterSingletonsInstantiated();
 
 		MockServerWebExchange exchange = MockServerHttpRequest.get("").toExchange();
 		setPathWithinHandlerMapping(exchange, "versionString/foo.css");
@@ -222,39 +218,12 @@ public void getResourceFromSubDirectoryOfAlternatePath() throws Exception {
 		assertResponseBody(exchange, "function foo() { console.log(\"hello world\"); }");
 	}
 
-	@Test // SPR-13658
-	public void getResourceWithRegisteredMediaType() throws Exception {
-		CompositeContentTypeResolver contentTypeResolver = new RequestedContentTypeResolverBuilder()
-				.mediaType("css", new MediaType("foo", "bar"))
-				.build();
-
-		List<Resource> paths = Collections.singletonList(new ClassPathResource("test/", getClass()));
-		ResourceWebHandler handler = new ResourceWebHandler();
-		handler.setLocations(paths);
-		handler.setContentTypeResolver(contentTypeResolver);
-		handler.afterPropertiesSet();
-		handler.afterSingletonsInstantiated();
-
-		MockServerWebExchange exchange = MockServerHttpRequest.get("").toExchange();
-		setPathWithinHandlerMapping(exchange, "foo.css");
-		handler.handle(exchange).block(TIMEOUT);
-
-		assertEquals(MediaType.parseMediaType("foo/bar"), exchange.getResponse().getHeaders().getContentType());
-		assertResponseBody(exchange, "h1 { color:red; }");
-	}
-
 	@Test // SPR-14577
 	public void getMediaTypeWithFavorPathExtensionOff() throws Exception {
-		CompositeContentTypeResolver contentTypeResolver = new RequestedContentTypeResolverBuilder()
-				.favorPathExtension(false)
-				.build();
-
 		List<Resource> paths = Collections.singletonList(new ClassPathResource("test/", getClass()));
 		ResourceWebHandler handler = new ResourceWebHandler();
 		handler.setLocations(paths);
-		handler.setContentTypeResolver(contentTypeResolver);
 		handler.afterPropertiesSet();
-		handler.afterSingletonsInstantiated();
 
 		MockServerWebExchange exchange = MockServerHttpRequest.get("")
 				.header("Accept", "application/json,text/plain,*/*").toExchange();
@@ -367,7 +336,6 @@ public void initAllowedLocationsWithExplicitConfiguration() throws Exception {
 		handler.setResourceResolvers(Collections.singletonList(pathResolver));
 		handler.setLocations(Arrays.asList(location1, location2));
 		handler.afterPropertiesSet();
-		handler.afterSingletonsInstantiated();
 
 		Resource[] locations = pathResolver.getAllowedLocations();
 		assertEquals(1, locations.length);