Resource handling support for Spring Web Reactive

A straight-forward port of the resource handling support in
spring-webmvc to spring-web-reactive. Primarily adapting contracts and
implementations to use the reactive request and response and the
reactive ResourceHttpMessageWriter.

Issue: SPR-14521

build.gradle

@@ -801,6 +801,7 @@ project("spring-web-reactive") {
 		optional("com.fasterxml.jackson.core:jackson-databind:${jackson2Version}")
 		optional("org.freemarker:freemarker:${freemarkerVersion}")
 		optional "org.apache.httpcomponents:httpclient:${httpclientVersion}"
+		optional('org.webjars:webjars-locator:0.32')
 		testCompile("javax.validation:validation-api:${beanvalVersion}")
 		testCompile("org.apache.tomcat:tomcat-util:${tomcatVersion}")
 		testCompile("org.apache.tomcat.embed:tomcat-embed-core:${tomcatVersion}")
@@ -822,6 +823,7 @@ project("spring-web-reactive") {
 		testRuntime("javax.activation:activation:${activationApiVersion}")
 		testRuntime("org.jboss.xnio:xnio-nio:${xnioVersion}")
 		testRuntime("org.jboss.logging:jboss-logging:3.3.0.Final")
+		testRuntime("org.webjars:underscorejs:1.8.3")
 	}
 }
 

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

@@ -23,7 +23,6 @@ import java.util.Locale;
 import java.util.Map;
 import java.util.Set;
 import java.util.concurrent.ConcurrentHashMap;
-import java.util.concurrent.ConcurrentMap;
 
 import org.springframework.http.MediaType;
 import org.springframework.util.LinkedMultiValueMap;
@@ -44,7 +43,7 @@ import org.springframework.web.server.ServerWebExchange;
 public abstract class AbstractMappingContentTypeResolver implements MappingContentTypeResolver {
 
 	/** Primary lookup for media types by key (e.g. "json" -> "application/json") */
-	private final ConcurrentMap<String, MediaType> mediaTypeLookup = new ConcurrentHashMap<>(64);
+	private final Map<String, MediaType> mediaTypeLookup = new ConcurrentHashMap<>(64);
 
 	/** Reverse lookup for keys associated with a media type */
 	private final MultiValueMap<MediaType, String> keyLookup = new LinkedMultiValueMap<>(64);
@@ -65,6 +64,10 @@ public abstract class AbstractMappingContentTypeResolver implements MappingConte
 	}
 
 
+	public Map<String, MediaType> getMediaTypes() {
+		return this.mediaTypeLookup;
+	}
+
 	/**
 	 * Sub-classes can use this method to look up a MediaType by key.
 	 * @param key the key converted to lower case
@@ -77,7 +80,7 @@ public abstract class AbstractMappingContentTypeResolver implements MappingConte
 	/**
 	 * Sub-classes can use this method get all mapped media types.
 	 */
-	protected List<MediaType> getMediaTypes() {
+	protected List<MediaType> getAllMediaTypes() {
 		return new ArrayList<>(this.mediaTypeLookup.values());
 	}
 

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

@@ -77,7 +77,7 @@ public class ParameterContentTypeResolver extends AbstractMappingContentTypeReso
 
 	@Override
 	protected MediaType handleNoMatch(String key) throws NotAcceptableStatusException {
-		throw new NotAcceptableStatusException(getMediaTypes());
+		throw new NotAcceptableStatusException(getAllMediaTypes());
 	}
 
 }

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

@@ -97,7 +97,7 @@ public class PathExtensionContentTypeResolver extends AbstractMappingContentType
 			}
 		}
 		if (!this.ignoreUnknownExtensions) {
-			throw new NotAcceptableStatusException(getMediaTypes());
+			throw new NotAcceptableStatusException(getAllMediaTypes());
 		}
 		return null;
 	}

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

@@ -218,7 +218,7 @@ public class RequestedContentTypeResolverBuilder {
 	}
 
 
-	public RequestedContentTypeResolver build() {
+	public CompositeContentTypeResolver build() {
 		List<RequestedContentTypeResolver> resolvers = new ArrayList<>();
 
 		if (this.favorPathExtension) {

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

@@ -0,0 +1,66 @@
+/*
+ * 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.
+ * 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.resource;
+
+import java.util.List;
+
+import org.apache.commons.logging.Log;
+import org.apache.commons.logging.LogFactory;
+
+import org.springframework.core.io.Resource;
+import org.springframework.web.server.ServerWebExchange;
+
+/**
+ * Base {@link ResourceResolver} providing consistent logging.
+ *
+ * @author Rossen Stoyanchev
+ * @since 5.0
+ */
+public abstract class AbstractResourceResolver implements ResourceResolver {
+
+	protected final Log logger = LogFactory.getLog(getClass());
+
+
+	@Override
+	public Resource resolveResource(ServerWebExchange exchange, String requestPath,
+			List<? extends Resource> locations, ResourceResolverChain chain) {
+
+		if (logger.isTraceEnabled()) {
+			logger.trace("Resolving resource for request path \"" + requestPath + "\"");
+		}
+		return resolveResourceInternal(exchange, requestPath, locations, chain);
+	}
+
+	@Override
+	public String resolveUrlPath(String resourceUrlPath, List<? extends Resource> locations,
+			ResourceResolverChain chain) {
+
+		if (logger.isTraceEnabled()) {
+			logger.trace("Resolving public URL for resource path \"" + resourceUrlPath + "\"");
+		}
+
+		return resolveUrlPathInternal(resourceUrlPath, locations, chain);
+	}
+
+
+	protected abstract Resource resolveResourceInternal(ServerWebExchange exchange, String requestPath,
+			List<? extends Resource> locations, ResourceResolverChain chain);
+
+	protected abstract String resolveUrlPathInternal(String resourceUrlPath,
+			List<? extends Resource> locations, ResourceResolverChain chain);
+
+}

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

@@ -0,0 +1,147 @@
+/*
+ * 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.
+ * 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.resource;
+
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
+
+import org.apache.commons.logging.Log;
+import org.apache.commons.logging.LogFactory;
+
+import org.springframework.util.Assert;
+import org.springframework.util.StringUtils;
+
+/**
+ * Abstract base class for {@link VersionStrategy} implementations.
+ *
+ * <p>Supports versions as:
+ * <ul>
+ * <li>prefix in the request path, like "version/static/myresource.js"
+ * <li>file name suffix in the request path, like "static/myresource-version.js"
+ * </ul>
+ *
+ * <p>Note: This base class does <i>not</i> provide support for generating the
+ * version string.
+ *
+ * @author Rossen Stoyanchev
+ * @author Brian Clozel
+ * @since 5.0
+ */
+public abstract class AbstractVersionStrategy implements VersionStrategy {
+
+	protected final Log logger = LogFactory.getLog(getClass());
+
+	private final VersionPathStrategy pathStrategy;
+
+
+	protected AbstractVersionStrategy(VersionPathStrategy pathStrategy) {
+		Assert.notNull(pathStrategy, "VersionPathStrategy is required");
+		this.pathStrategy = pathStrategy;
+	}
+
+
+	public VersionPathStrategy getVersionPathStrategy() {
+		return this.pathStrategy;
+	}
+
+
+	@Override
+	public String extractVersion(String requestPath) {
+		return this.pathStrategy.extractVersion(requestPath);
+	}
+
+	@Override
+	public String removeVersion(String requestPath, String version) {
+		return this.pathStrategy.removeVersion(requestPath, version);
+	}
+
+	@Override
+	public String addVersion(String requestPath, String version) {
+		return this.pathStrategy.addVersion(requestPath, version);
+	}
+
+
+	/**
+	 * A prefix-based {@code VersionPathStrategy},
+	 * e.g. {@code "{version}/path/foo.js"}.
+	 */
+	protected static class PrefixVersionPathStrategy implements VersionPathStrategy {
+
+		private final String prefix;
+
+		public PrefixVersionPathStrategy(String version) {
+			Assert.hasText(version, "'version' must not be empty");
+			this.prefix = version;
+		}
+
+		@Override
+		public String extractVersion(String requestPath) {
+			return (requestPath.startsWith(this.prefix) ? this.prefix : null);
+		}
+
+		@Override
+		public String removeVersion(String requestPath, String version) {
+			return requestPath.substring(this.prefix.length());
+		}
+
+		@Override
+		public String addVersion(String path, String version) {
+			if (path.startsWith(".")) {
+				return path;
+			}
+			else {
+				return (this.prefix.endsWith("/") || path.startsWith("/") ?
+						this.prefix + path : this.prefix + "/" + path);
+			}
+		}
+	}
+
+
+	/**
+	 * File name-based {@code VersionPathStrategy},
+	 * e.g. {@code "path/foo-{version}.css"}.
+	 */
+	protected static class FileNameVersionPathStrategy implements VersionPathStrategy {
+
+		private static final Pattern pattern = Pattern.compile("-(\\S*)\\.");
+
+		@Override
+		public String extractVersion(String requestPath) {
+			Matcher matcher = pattern.matcher(requestPath);
+			if (matcher.find()) {
+				String match = matcher.group(1);
+				return (match.contains("-") ? match.substring(match.lastIndexOf("-") + 1) : match);
+			}
+			else {
+				return null;
+			}
+		}
+
+		@Override
+		public String removeVersion(String requestPath, String version) {
+			return StringUtils.delete(requestPath, "-" + version);
+		}
+
+		@Override
+		public String addVersion(String requestPath, String version) {
+			String baseFilename = StringUtils.stripFilenameExtension(requestPath);
+			String extension = StringUtils.getFilenameExtension(requestPath);
+			return (baseFilename + "-" + version + "." + extension);
+		}
+	}
+
+}

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

@@ -0,0 +1,231 @@
+/*
+ * 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.
+ * 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.resource;
+
+import java.io.ByteArrayOutputStream;
+import java.io.IOException;
+import java.io.StringWriter;
+import java.nio.charset.Charset;
+import java.nio.charset.StandardCharsets;
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.Map;
+import java.util.Scanner;
+
+import org.apache.commons.logging.Log;
+import org.apache.commons.logging.LogFactory;
+
+import org.springframework.core.io.Resource;
+import org.springframework.util.DigestUtils;
+import org.springframework.util.FileCopyUtils;
+import org.springframework.util.StringUtils;
+import org.springframework.web.server.ServerWebExchange;
+
+/**
+ * A {@link ResourceTransformer} implementation that helps handling resources
+ * within HTML5 AppCache manifests for HTML5 offline applications.
+ *
+ * <p>This transformer:
+ * <ul>
+ * <li>modifies links to match the public URL paths that should be exposed to
+ * clients, using configured {@code ResourceResolver} strategies
+ * <li>appends a comment in the manifest, containing a Hash
+ * (e.g. "# Hash: 9de0f09ed7caf84e885f1f0f11c7e326"), thus changing the content
+ * of the manifest in order to trigger an appcache reload in the browser.
+ * </ul>
+ *
+ * All files that have the ".manifest" file extension, or the extension given
+ * in the constructor, will be transformed by this class.
+ *
+ * <p>This hash is computed using the content of the appcache manifest and the
+ * content of the linked resources; so changing a resource linked in the manifest
+ * or the manifest itself should invalidate the browser cache.
+ *
+ * @author Rossen Stoyanchev
+ * @author Brian Clozel
+ * @since 5.0
+ * @see <a href="http://www.whatwg.org/specs/web-apps/current-work/multipage/offline.html#offline">HTML5 offline applications spec</a>
+ */
+public class AppCacheManifestTransformer extends ResourceTransformerSupport {
+
+	private static final String MANIFEST_HEADER = "CACHE MANIFEST";
+
+	private static final Charset DEFAULT_CHARSET = StandardCharsets.UTF_8;
+
+	private static final Log logger = LogFactory.getLog(AppCacheManifestTransformer.class);
+
+
+	private final Map<String, SectionTransformer> sectionTransformers = new HashMap<>();
+
+	private final String fileExtension;
+
+
+	/**
+	 * Create an AppCacheResourceTransformer that transforms files with extension ".manifest".
+	 */
+	public AppCacheManifestTransformer() {
+		this("manifest");
+	}
+
+	/**
+	 * Create an AppCacheResourceTransformer that transforms files with the extension
+	 * given as a parameter.
+	 */
+	public AppCacheManifestTransformer(String fileExtension) {
+		this.fileExtension = fileExtension;
+
+		SectionTransformer noOpSection = new NoOpSection();
+		this.sectionTransformers.put(MANIFEST_HEADER, noOpSection);
+		this.sectionTransformers.put("NETWORK:", noOpSection);
+		this.sectionTransformers.put("FALLBACK:", noOpSection);
+		this.sectionTransformers.put("CACHE:", new CacheSection());
+	}
+
+
+	@Override
+	public Resource transform(ServerWebExchange exchange, Resource resource,
+			ResourceTransformerChain transformerChain) throws IOException {
+
+		resource = transformerChain.transform(exchange, resource);
+		if (!this.fileExtension.equals(StringUtils.getFilenameExtension(resource.getFilename()))) {
+			return resource;
+		}
+
+		byte[] bytes = FileCopyUtils.copyToByteArray(resource.getInputStream());
+		String content = new String(bytes, DEFAULT_CHARSET);
+
+		if (!content.startsWith(MANIFEST_HEADER)) {
+			if (logger.isTraceEnabled()) {
+				logger.trace("AppCache manifest does not start with 'CACHE MANIFEST', skipping: " + resource);
+			}
+			return resource;
+		}
+
+		if (logger.isTraceEnabled()) {
+			logger.trace("Transforming resource: " + resource);
+		}
+
+		StringWriter contentWriter = new StringWriter();
+		HashBuilder hashBuilder = new HashBuilder(content.length());
+
+		Scanner scanner = new Scanner(content);
+		SectionTransformer currentTransformer = this.sectionTransformers.get(MANIFEST_HEADER);
+		while (scanner.hasNextLine()) {
+			String line = scanner.nextLine();
+			if (this.sectionTransformers.containsKey(line.trim())) {
+				currentTransformer = this.sectionTransformers.get(line.trim());
+				contentWriter.write(line + "\n");
+				hashBuilder.appendString(line);
+			}
+			else {
+				contentWriter.write(
+						currentTransformer.transform(
+								line, hashBuilder, resource, transformerChain, exchange)  + "\n");
+			}
+		}
+
+		String hash = hashBuilder.build();
+		contentWriter.write("\n" + "# Hash: " + hash);
+		if (logger.isTraceEnabled()) {
+			logger.trace("AppCache file: [" + resource.getFilename()+ "] hash: [" + hash + "]");
+		}
+
+		return new TransformedResource(resource, contentWriter.toString().getBytes(DEFAULT_CHARSET));
+	}
+
+
+	@FunctionalInterface
+	private interface SectionTransformer {
+
+		/**
+		 * Transforms a line in a section of the manifest.
+		 * <p>The actual transformation depends on the chosen transformation strategy
+		 * for the current manifest section (CACHE, NETWORK, FALLBACK, etc).
+		 */
+		String transform(String line, HashBuilder builder, Resource resource,
+				ResourceTransformerChain transformerChain, ServerWebExchange exchange) throws IOException;
+	}
+
+
+	private static class NoOpSection implements SectionTransformer {
+
+		public String transform(String line, HashBuilder builder, Resource resource,
+				ResourceTransformerChain transformerChain, ServerWebExchange exchange) throws IOException {
+
+			builder.appendString(line);
+			return line;
+		}
+	}
+
+
+	private class CacheSection implements SectionTransformer {
+
+		private static final String COMMENT_DIRECTIVE = "#";
+
+		@Override
+		public String transform(String line, HashBuilder builder, Resource resource,
+				ResourceTransformerChain transformerChain, ServerWebExchange exchange) throws IOException {
+
+			if (isLink(line) && !hasScheme(line)) {
+				ResourceResolverChain resolverChain = transformerChain.getResolverChain();
+				Resource appCacheResource =
+						resolverChain.resolveResource(null, line, Collections.singletonList(resource));
+				String path = resolveUrlPath(line, exchange, resource, transformerChain);
+				builder.appendResource(appCacheResource);
+				if (logger.isTraceEnabled()) {
+					logger.trace("Link modified: " + path + " (original: " + line + ")");
+				}
+				return path;
+			}
+			builder.appendString(line);
+			return line;
+		}
+
+		private boolean hasScheme(String link) {
+			int schemeIndex = link.indexOf(":");
+			return (link.startsWith("//") || (schemeIndex > 0 && !link.substring(0, schemeIndex).contains("/")));
+		}
+
+		private boolean isLink(String line) {
+			return (StringUtils.hasText(line) && !line.startsWith(COMMENT_DIRECTIVE));
+		}
+	}
+
+
+	private static class HashBuilder {
+
+		private final ByteArrayOutputStream baos;
+
+		public HashBuilder(int initialSize) {
+			this.baos = new ByteArrayOutputStream(initialSize);
+		}
+
+		public void appendResource(Resource resource) throws IOException {
+			byte[] content = FileCopyUtils.copyToByteArray(resource.getInputStream());
+			this.baos.write(DigestUtils.md5Digest(content));
+		}
+
+		public void appendString(String content) throws IOException {
+			this.baos.write(content.getBytes(DEFAULT_CHARSET));
+		}
+
+		public String build() {
+			return DigestUtils.md5DigestAsHex(this.baos.toByteArray());
+		}
+	}
+
+}

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

@@ -0,0 +1,125 @@
+/*
+ * 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.
+ * 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.resource;
+
+import java.util.List;
+
+import org.springframework.cache.Cache;
+import org.springframework.cache.CacheManager;
+import org.springframework.core.io.Resource;
+import org.springframework.util.Assert;
+import org.springframework.web.server.ServerWebExchange;
+
+/**
+ * A {@link ResourceResolver} that resolves resources from a {@link Cache} or
+ * otherwise delegates to the resolver chain and caches the result.
+ *
+ * @author Rossen Stoyanchev
+ * @author Brian Clozel
+ * @since 5.0
+ */
+public class CachingResourceResolver extends AbstractResourceResolver {
+
+	public static final String RESOLVED_RESOURCE_CACHE_KEY_PREFIX = "resolvedResource:";
+
+	public static final String RESOLVED_URL_PATH_CACHE_KEY_PREFIX = "resolvedUrlPath:";
+
+
+	private final Cache cache;
+
+
+	public CachingResourceResolver(CacheManager cacheManager, String cacheName) {
+		this(cacheManager.getCache(cacheName));
+	}
+
+	public CachingResourceResolver(Cache cache) {
+		Assert.notNull(cache, "Cache is required");
+		this.cache = cache;
+	}
+
+
+	/**
+	 * Return the configured {@code Cache}.
+	 */
+	public Cache getCache() {
+		return this.cache;
+	}
+
+
+	@Override
+	protected Resource resolveResourceInternal(ServerWebExchange exchange, String requestPath,
+			List<? extends Resource> locations, ResourceResolverChain chain) {
+
+		String key = computeKey(exchange, requestPath);
+		Resource resource = this.cache.get(key, Resource.class);
+
+		if (resource != null) {
+			if (logger.isTraceEnabled()) {
+				logger.trace("Found match: " + resource);
+			}
+			return resource;
+		}
+
+		resource = chain.resolveResource(exchange, requestPath, locations);
+		if (resource != null) {
+			if (logger.isTraceEnabled()) {
+				logger.trace("Putting resolved resource in cache: " + resource);
+			}
+			this.cache.put(key, resource);
+		}
+
+		return resource;
+	}
+
+	protected String computeKey(ServerWebExchange exchange, String requestPath) {
+		StringBuilder key = new StringBuilder(RESOLVED_RESOURCE_CACHE_KEY_PREFIX);
+		key.append(requestPath);
+		if (exchange != null) {
+			String encoding = exchange.getRequest().getHeaders().getFirst("Accept-Encoding");
+			if (encoding != null && encoding.contains("gzip")) {
+				key.append("+encoding=gzip");
+			}
+		}
+		return key.toString();
+	}
+
+	@Override
+	protected String resolveUrlPathInternal(String resourceUrlPath,
+			List<? extends Resource> locations, ResourceResolverChain chain) {
+
+		String key = RESOLVED_URL_PATH_CACHE_KEY_PREFIX + resourceUrlPath;
+		String resolvedUrlPath = this.cache.get(key, String.class);
+
+		if (resolvedUrlPath != null) {
+			if (logger.isTraceEnabled()) {
+				logger.trace("Found match: \"" + resolvedUrlPath + "\"");
+			}
+			return resolvedUrlPath;
+		}
+
+		resolvedUrlPath = chain.resolveUrlPath(resourceUrlPath, locations);
+		if (resolvedUrlPath != null) {
+			if (logger.isTraceEnabled()) {
+				logger.trace("Putting resolved resource URL path in cache: \"" + resolvedUrlPath + "\"");
+			}
+			this.cache.put(key, resolvedUrlPath);
+		}
+
+		return resolvedUrlPath;
+	}
+
+}

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

@@ -0,0 +1,85 @@
+/*
+ * 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.
+ * 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.resource;
+
+import java.io.IOException;
+
+import org.apache.commons.logging.Log;
+import org.apache.commons.logging.LogFactory;
+
+import org.springframework.cache.Cache;
+import org.springframework.cache.CacheManager;
+import org.springframework.core.io.Resource;
+import org.springframework.util.Assert;
+import org.springframework.web.server.ServerWebExchange;
+
+/**
+ * A {@link ResourceTransformer} that checks a {@link Cache} to see if a
+ * previously transformed resource exists in the cache and returns it if found,
+ * or otherwise delegates to the resolver chain and caches the result.
+ *
+ * @author Rossen Stoyanchev
+ * @since 5.0
+ */
+public class CachingResourceTransformer implements ResourceTransformer {
+
+	private static final Log logger = LogFactory.getLog(CachingResourceTransformer.class);
+
+	private final Cache cache;
+
+
+	public CachingResourceTransformer(CacheManager cacheManager, String cacheName) {
+		this(cacheManager.getCache(cacheName));
+	}
+
+	public CachingResourceTransformer(Cache cache) {
+		Assert.notNull(cache, "Cache is required");
+		this.cache = cache;
+	}
+
+
+	/**
+	 * Return the configured {@code Cache}.
+	 */
+	public Cache getCache() {
+		return this.cache;
+	}
+
+
+	@Override
+	public Resource transform(ServerWebExchange exchange, Resource resource,
+			ResourceTransformerChain transformerChain) throws IOException {
+
+		Resource transformed = this.cache.get(resource, Resource.class);
+		if (transformed != null) {
+			if (logger.isTraceEnabled()) {
+				logger.trace("Found match: " + transformed);
+			}
+			return transformed;
+		}
+
+		transformed = transformerChain.transform(exchange, resource);
+
+		if (logger.isTraceEnabled()) {
+			logger.trace("Putting transformed resource in cache: " + transformed);
+		}
+		this.cache.put(resource, transformed);
+
+		return transformed;
+	}
+
+}

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

@@ -0,0 +1,54 @@
+/*
+ * 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.
+ * 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.resource;
+
+import java.io.IOException;
+
+import org.springframework.core.io.Resource;
+import org.springframework.util.DigestUtils;
+import org.springframework.util.FileCopyUtils;
+
+/**
+ * A {@code VersionStrategy} that calculates an Hex MD5 hashes from the content
+ * of the resource and appends it to the file name, e.g.
+ * {@code "styles/main-e36d2e05253c6c7085a91522ce43a0b4.css"}.
+ *
+ * @author Rossen Stoyanchev
+ * @author Brian Clozel
+ * @since 5.0
+ * @see VersionResourceResolver
+ */
+public class ContentVersionStrategy extends AbstractVersionStrategy {
+
+
+	public ContentVersionStrategy() {
+		super(new FileNameVersionPathStrategy());
+	}
+
+
+	@Override
+	public String getResourceVersion(Resource resource) {
+		try {
+			byte[] content = FileCopyUtils.copyToByteArray(resource.getInputStream());
+			return DigestUtils.md5DigestAsHex(content);
+		}
+		catch (IOException ex) {
+			throw new IllegalStateException("Failed to calculate hash for " + resource, ex);
+		}
+	}
+
+}

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

@@ -0,0 +1,270 @@
+/*
+ * 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.
+ * 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.resource;
+
+import java.io.IOException;
+import java.io.StringWriter;
+import java.nio.charset.Charset;
+import java.nio.charset.StandardCharsets;
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.HashSet;
+import java.util.List;
+import java.util.Set;
+
+import org.apache.commons.logging.Log;
+import org.apache.commons.logging.LogFactory;
+
+import org.springframework.core.io.Resource;
+import org.springframework.util.FileCopyUtils;
+import org.springframework.util.StringUtils;
+import org.springframework.web.server.ServerWebExchange;
+
+/**
+ * A {@link ResourceTransformer} implementation that modifies links in a CSS
+ * file to match the public URL paths that should be exposed to clients (e.g.
+ * with an MD5 content-based hash inserted in the URL).
+ *
+ * <p>The implementation looks for links in CSS {@code @import} statements and
+ * also inside CSS {@code url()} functions. All links are then passed through the
+ * {@link ResourceResolverChain} and resolved relative to the location of the
+ * containing CSS file. If successfully resolved, the link is modified, otherwise
+ * the original link is preserved.
+ *
+ * @author Rossen Stoyanchev
+ * @since 5.0
+ */
+public class CssLinkResourceTransformer extends ResourceTransformerSupport {
+
+	private static final Charset DEFAULT_CHARSET = StandardCharsets.UTF_8;
+
+	private static final Log logger = LogFactory.getLog(CssLinkResourceTransformer.class);
+
+	private final List<CssLinkParser> linkParsers = new ArrayList<>(2);
+
+
+	public CssLinkResourceTransformer() {
+		this.linkParsers.add(new ImportStatementCssLinkParser());
+		this.linkParsers.add(new UrlFunctionCssLinkParser());
+	}
+
+
+	@Override
+	public Resource transform(ServerWebExchange exchange, Resource resource,
+			ResourceTransformerChain transformerChain) throws IOException {
+
+		resource = transformerChain.transform(exchange, resource);
+
+		String filename = resource.getFilename();
+		if (!"css".equals(StringUtils.getFilenameExtension(filename))) {
+			return resource;
+		}
+
+		if (logger.isTraceEnabled()) {
+			logger.trace("Transforming resource: " + resource);
+		}
+
+		byte[] bytes = FileCopyUtils.copyToByteArray(resource.getInputStream());
+		String content = new String(bytes, DEFAULT_CHARSET);
+
+		Set<CssLinkInfo> infos = new HashSet<>(8);
+		for (CssLinkParser parser : this.linkParsers) {
+			parser.parseLink(content, infos);
+		}
+
+		if (infos.isEmpty()) {
+			if (logger.isTraceEnabled()) {
+				logger.trace("No links found.");
+			}
+			return resource;
+		}
+
+		List<CssLinkInfo> sortedInfos = new ArrayList<>(infos);
+		Collections.sort(sortedInfos);
+
+		int index = 0;
+		StringWriter writer = new StringWriter();
+		for (CssLinkInfo info : sortedInfos) {
+			writer.write(content.substring(index, info.getStart()));
+			String link = content.substring(info.getStart(), info.getEnd());
+			String newLink = null;
+			if (!hasScheme(link)) {
+				newLink = resolveUrlPath(link, exchange, resource, transformerChain);
+			}
+			if (logger.isTraceEnabled()) {
+				if (newLink != null && !link.equals(newLink)) {
+					logger.trace("Link modified: " + newLink + " (original: " + link + ")");
+				}
+				else {
+					logger.trace("Link not modified: " + link);
+				}
+			}
+			writer.write(newLink != null ? newLink : link);
+			index = info.getEnd();
+		}
+		writer.write(content.substring(index));
+
+		return new TransformedResource(resource, writer.toString().getBytes(DEFAULT_CHARSET));
+	}
+
+	private boolean hasScheme(String link) {
+		int schemeIndex = link.indexOf(":");
+		return (schemeIndex > 0 && !link.substring(0, schemeIndex).contains("/")) || link.indexOf("//") == 0;
+	}
+
+
+	@FunctionalInterface
+	protected interface CssLinkParser {
+
+		void parseLink(String content, Set<CssLinkInfo> linkInfos);
+	}
+
+
+	protected static abstract class AbstractCssLinkParser implements CssLinkParser {
+
+		/**
+		 * Return the keyword to use to search for links.
+		 */
+		protected abstract String getKeyword();
+
+		@Override
+		public void parseLink(String content, Set<CssLinkInfo> linkInfos) {
+			int index = 0;
+			do {
+				index = content.indexOf(getKeyword(), index);
+				if (index == -1) {
+					break;
+				}
+				index = skipWhitespace(content, index + getKeyword().length());
+				if (content.charAt(index) == '\'') {
+					index = addLink(index, "'", content, linkInfos);
+				}
+				else if (content.charAt(index) == '"') {
+					index = addLink(index, "\"", content, linkInfos);
+				}
+				else {
+					index = extractLink(index, content, linkInfos);
+
+				}
+			}
+			while (true);
+		}
+
+		private int skipWhitespace(String content, int index) {
+			while (true) {
+				if (Character.isWhitespace(content.charAt(index))) {
+					index++;
+					continue;
+				}
+				return index;
+			}
+		}
+
+		protected int addLink(int index, String endKey, String content, Set<CssLinkInfo> linkInfos) {
+			int start = index + 1;
+			int end = content.indexOf(endKey, start);
+			linkInfos.add(new CssLinkInfo(start, end));
+			return end + endKey.length();
+		}
+
+		/**
+		 * Invoked after a keyword match, after whitespaces removed, and when
+		 * the next char is neither a single nor double quote.
+		 */
+		protected abstract int extractLink(int index, String content, Set<CssLinkInfo> linkInfos);
+
+	}
+
+
+	private static class ImportStatementCssLinkParser extends AbstractCssLinkParser {
+
+		@Override
+		protected String getKeyword() {
+			return "@import";
+		}
+
+		@Override
+		protected int extractLink(int index, String content, Set<CssLinkInfo> linkInfos) {
+			if (content.substring(index, index + 4).equals("url(")) {
+				// Ignore, UrlLinkParser will take care
+			}
+			else if (logger.isErrorEnabled()) {
+				logger.error("Unexpected syntax for @import link at index " + index);
+			}
+			return index;
+		}
+	}
+
+
+	private static class UrlFunctionCssLinkParser extends AbstractCssLinkParser {
+
+		@Override
+		protected String getKeyword() {
+			return "url(";
+		}
+
+		@Override
+		protected int extractLink(int index, String content, Set<CssLinkInfo> linkInfos) {
+			// A url() function without unquoted
+			return addLink(index - 1, ")", content, linkInfos);
+		}
+	}
+
+
+	private static class CssLinkInfo implements Comparable<CssLinkInfo> {
+
+		private final int start;
+
+		private final int end;
+
+		public CssLinkInfo(int start, int end) {
+			this.start = start;
+			this.end = end;
+		}
+
+		public int getStart() {
+			return this.start;
+		}
+
+		public int getEnd() {
+			return this.end;
+		}
+
+		@Override
+		public int compareTo(CssLinkInfo other) {
+			return (this.start < other.start ? -1 : (this.start == other.start ? 0 : 1));
+		}
+
+		@Override
+		public boolean equals(Object obj) {
+			if (this == obj) {
+				return true;
+			}
+			if (obj != null && obj instanceof CssLinkInfo) {
+				CssLinkInfo other = (CssLinkInfo) obj;
+				return (this.start == other.start && this.end == other.end);
+			}
+			return false;
+		}
+
+		@Override
+		public int hashCode() {
+			return this.start * 31 + this.end;
+		}
+	}
+
+}

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

@@ -0,0 +1,90 @@
+/*
+ * 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.
+ * 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.resource;
+
+import java.util.ArrayList;
+import java.util.List;
+
+import org.springframework.core.io.Resource;
+import org.springframework.util.Assert;
+import org.springframework.web.server.ServerWebExchange;
+
+/**
+ * A default implementation of {@link ResourceResolverChain} for invoking a list
+ * of {@link ResourceResolver}s.
+ *
+ * @author Rossen Stoyanchev
+ * @since 5.0
+ */
+class DefaultResourceResolverChain implements ResourceResolverChain {
+
+	private final List<ResourceResolver> resolvers = new ArrayList<>();
+
+	private int index = -1;
+
+
+	public DefaultResourceResolverChain(List<? extends ResourceResolver> resolvers) {
+		if (resolvers != null) {
+			this.resolvers.addAll(resolvers);
+		}
+	}
+
+
+	@Override
+	public Resource resolveResource(ServerWebExchange exchange, String requestPath,
+			List<? extends Resource> locations) {
+
+		ResourceResolver resolver = getNext();
+		if (resolver == null) {
+			return null;
+		}
+
+		try {
+			return resolver.resolveResource(exchange, requestPath, locations, this);
+		}
+		finally {
+			this.index--;
+		}
+	}
+
+	@Override
+	public String resolveUrlPath(String resourcePath, List<? extends Resource> locations) {
+		ResourceResolver resolver = getNext();
+		if (resolver == null) {
+			return null;
+		}
+
+		try {
+			return resolver.resolveUrlPath(resourcePath, locations, this);
+		}
+		finally {
+			this.index--;
+		}
+	}
+
+	private ResourceResolver getNext() {
+		Assert.state(this.index <= this.resolvers.size(),
+				"Current index exceeds the number of configured ResourceResolvers");
+
+		if (this.index == (this.resolvers.size() - 1)) {
+			return null;
+		}
+		this.index++;
+		return this.resolvers.get(this.index);
+	}
+
+}

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

@@ -0,0 +1,85 @@
+/*
+ * 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.
+ * 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.resource;
+
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.List;
+
+import org.springframework.core.io.Resource;
+import org.springframework.util.Assert;
+import org.springframework.web.server.ServerWebExchange;
+
+/**
+ * A default implementation of {@link ResourceTransformerChain} for invoking
+ * a list of {@link ResourceTransformer}s.
+ *
+ * @author Rossen Stoyanchev
+ * @since 5.0
+ */
+class DefaultResourceTransformerChain implements ResourceTransformerChain {
+
+	private final ResourceResolverChain resolverChain;
+
+	private final List<ResourceTransformer> transformers = new ArrayList<>();
+
+	private int index = -1;
+
+
+	public DefaultResourceTransformerChain(ResourceResolverChain resolverChain,
+			List<ResourceTransformer> transformers) {
+
+		Assert.notNull(resolverChain, "ResourceResolverChain is required");
+		this.resolverChain = resolverChain;
+		if (transformers != null) {
+			this.transformers.addAll(transformers);
+		}
+	}
+
+
+	public ResourceResolverChain getResolverChain() {
+		return this.resolverChain;
+	}
+
+
+	@Override
+	public Resource transform(ServerWebExchange exchange, Resource resource) throws IOException {
+		ResourceTransformer transformer = getNext();
+		if (transformer == null) {
+			return resource;
+		}
+		try {
+			return transformer.transform(exchange, resource, this);
+		}
+		finally {
+			this.index--;
+		}
+	}
+
+	private ResourceTransformer getNext() {
+		Assert.state(this.index <= this.transformers.size(),
+				"Current index exceeds the number of configured ResourceTransformer's");
+
+		if (this.index == (this.transformers.size() - 1)) {
+			return null;
+		}
+
+		this.index++;
+		return this.transformers.get(this.index);
+	}
+
+}

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

@@ -0,0 +1,43 @@
+/*
+ * 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.resource;
+
+import org.springframework.core.io.Resource;
+
+/**
+ * Interface for a resource descriptor that describes the encoding
+ * applied to the entire resource content.
+ *
+ * <p>This information is required if the client consuming that resource
+ * needs additional decoding capabilities to retrieve the resource's content.
+ *
+ * @author Rossen Stoyanchev
+ * @since 5.0
+ * @see <a href="http://tools.ietf.org/html/rfc7231#section-3.1.2.2">
+ *     HTTP/1.1: Semantics and Content, section 3.1.2.2</a>
+ */
+public interface EncodedResource extends Resource {
+
+	/**
+	 * The content coding value, as defined in the IANA registry
+	 * @return the content encoding
+	 * @see <a href="http://tools.ietf.org/html/rfc7231#section-3.1.2.1">HTTP/1.1: Semantics
+	 * and Content, section 3.1.2.1</a>
+	 */
+	String getContentEncoding();
+
+}

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

@@ -0,0 +1,54 @@
+/*
+ * 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.
+ * 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.resource;
+
+import org.springframework.core.io.Resource;
+
+/**
+ * A {@code VersionStrategy} that relies on a fixed version applied as a request
+ * path prefix, e.g. reduced SHA, version name, release date, etc.
+ *
+ * <p>This is useful for example when {@link ContentVersionStrategy} cannot be
+ * used such as when using JavaScript module loaders which are in charge of
+ * loading the JavaScript resources and need to know their relative paths.
+ *
+ * @author Rossen Stoyanchev
+ * @author Brian Clozel
+ * @since 5.0
+ * @see VersionResourceResolver
+ */
+public class FixedVersionStrategy extends AbstractVersionStrategy {
+
+	private final String version;
+
+
+	/**
+	 * Create a new FixedVersionStrategy with the given version string.
+	 * @param version the fixed version string to use
+	 */
+	public FixedVersionStrategy(String version) {
+		super(new PrefixVersionPathStrategy(version));
+		this.version = version;
+	}
+
+
+	@Override
+	public String getResourceVersion(Resource resource) {
+		return this.version;
+	}
+
+}

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

@@ -0,0 +1,146 @@
+/*
+ * 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.
+ * 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.resource;
+
+import java.io.File;
+import java.io.IOException;
+import java.io.InputStream;
+import java.net.URI;
+import java.net.URL;
+import java.util.List;
+
+import org.springframework.core.io.AbstractResource;
+import org.springframework.core.io.Resource;
+import org.springframework.web.server.ServerWebExchange;
+
+/**
+ * A {@code ResourceResolver} that delegates to the chain to locate a resource
+ * and then attempts to find a variation with the ".gz" extension.
+ *
+ * <p>The resolver gets involved only if the "Accept-Encoding" request header
+ * contains the value "gzip" indicating the client accepts gzipped responses.
+ *
+ * @author Rossen Stoyanchev
+ * @since 5.0
+ */
+public class GzipResourceResolver extends AbstractResourceResolver {
+
+	@Override
+	protected Resource resolveResourceInternal(ServerWebExchange exchange, String requestPath,
+			List<? extends Resource> locations, ResourceResolverChain chain) {
+
+		Resource resource = chain.resolveResource(exchange, requestPath, locations);
+		if ((resource == null) || (exchange != null && !isGzipAccepted(exchange))) {
+			return resource;
+		}
+
+		try {
+			Resource gzipped = new GzippedResource(resource);
+			if (gzipped.exists()) {
+				return gzipped;
+			}
+		}
+		catch (IOException ex) {
+			logger.trace("No gzipped resource for [" + resource.getFilename() + "]", ex);
+		}
+
+		return resource;
+	}
+
+	private boolean isGzipAccepted(ServerWebExchange exchange) {
+		String value = exchange.getRequest().getHeaders().getFirst("Accept-Encoding");
+		return (value != null && value.toLowerCase().contains("gzip"));
+	}
+
+	@Override
+	protected String resolveUrlPathInternal(String resourceUrlPath, List<? extends Resource> locations,
+			ResourceResolverChain chain) {
+
+		return chain.resolveUrlPath(resourceUrlPath, locations);
+	}
+
+
+	private static final class GzippedResource extends AbstractResource implements EncodedResource {
+
+		private final Resource original;
+
+		private final Resource gzipped;
+
+		public GzippedResource(Resource original) throws IOException {
+			this.original = original;
+			this.gzipped = original.createRelative(original.getFilename() + ".gz");
+		}
+
+		public InputStream getInputStream() throws IOException {
+			return this.gzipped.getInputStream();
+		}
+
+		public boolean exists() {
+			return this.gzipped.exists();
+		}
+
+		public boolean isReadable() {
+			return this.gzipped.isReadable();
+		}
+
+		public boolean isOpen() {
+			return this.gzipped.isOpen();
+		}
+
+		@Override
+		public boolean isFile() {
+			return this.gzipped.isFile();
+		}
+
+		public URL getURL() throws IOException {
+			return this.gzipped.getURL();
+		}
+
+		public URI getURI() throws IOException {
+			return this.gzipped.getURI();
+		}
+
+		public File getFile() throws IOException {
+			return this.gzipped.getFile();
+		}
+
+		public long contentLength() throws IOException {
+			return this.gzipped.contentLength();
+		}
+
+		public long lastModified() throws IOException {
+			return this.gzipped.lastModified();
+		}
+
+		public Resource createRelative(String relativePath) throws IOException {
+			return this.gzipped.createRelative(relativePath);
+		}
+
+		public String getFilename() {
+			return this.original.getFilename();
+		}
+
+		public String getDescription() {
+			return this.gzipped.getDescription();
+		}
+
+		public String getContentEncoding() {
+			return "gzip";
+		}
+	}
+
+}

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

@@ -0,0 +1,196 @@
+/*
+ * 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.
+ * 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.resource;
+
+import java.io.IOException;
+import java.net.URLDecoder;
+import java.util.Arrays;
+import java.util.List;
+
+import org.springframework.core.io.ClassPathResource;
+import org.springframework.core.io.Resource;
+import org.springframework.core.io.UrlResource;
+import org.springframework.util.StringUtils;
+import org.springframework.web.server.ServerWebExchange;
+
+/**
+ * A simple {@code ResourceResolver} that tries to find a resource under the given
+ * locations matching to the request path.
+ *
+ * <p>This resolver does not delegate to the {@code ResourceResolverChain} and is
+ * expected to be configured at the end in a chain of resolvers.
+ *
+ * @author Rossen Stoyanchev
+ * @since 5.0
+ */
+public class PathResourceResolver extends AbstractResourceResolver {
+
+	private Resource[] allowedLocations;
+
+
+	/**
+	 * By default when a Resource is found, the path of the resolved resource is
+	 * compared to ensure it's under the input location where it was found.
+	 * However sometimes that may not be the case, e.g. when
+	 * {@link CssLinkResourceTransformer}
+	 * resolves public URLs of links it contains, the CSS file is the location
+	 * and the resources being resolved are css files, images, fonts and others
+	 * located in adjacent or parent directories.
+	 * <p>This property allows configuring a complete list of locations under
+	 * which resources must be so that if a resource is not under the location
+	 * relative to which it was found, this list may be checked as well.
+	 * <p>By default {@link ResourceWebHandler} initializes this property
+	 * to match its list of locations.
+	 * @param locations the list of allowed locations
+	 */
+	public void setAllowedLocations(Resource... locations) {
+		this.allowedLocations = locations;
+	}
+
+	public Resource[] getAllowedLocations() {
+		return this.allowedLocations;
+	}
+
+
+	@Override
+	protected Resource resolveResourceInternal(ServerWebExchange exchange, String requestPath,
+			List<? extends Resource> locations, ResourceResolverChain chain) {
+
+		return getResource(requestPath, locations);
+	}
+
+	@Override
+	protected String resolveUrlPathInternal(String path, List<? extends Resource> locations,
+			ResourceResolverChain chain) {
+
+		return (StringUtils.hasText(path) && getResource(path, locations) != null ? path : null);
+	}
+
+	private Resource getResource(String resourcePath, List<? extends Resource> locations) {
+		for (Resource location : locations) {
+			try {
+				if (logger.isTraceEnabled()) {
+					logger.trace("Checking location: " + location);
+				}
+				Resource resource = getResource(resourcePath, location);
+				if (resource != null) {
+					if (logger.isTraceEnabled()) {
+						logger.trace("Found match: " + resource);
+					}
+					return resource;
+				}
+				else if (logger.isTraceEnabled()) {
+					logger.trace("No match for location: " + location);
+				}
+			}
+			catch (IOException ex) {
+				logger.trace("Failure checking for relative resource - trying next location", ex);
+			}
+		}
+		return null;
+	}
+
+	/**
+	 * Find the resource under the given location.
+	 * <p>The default implementation checks if there is a readable
+	 * {@code Resource} for the given path relative to the location.
+	 * @param resourcePath the path to the resource
+	 * @param location the location to check
+	 * @return the resource, or {@code null} if none found
+	 */
+	protected Resource getResource(String resourcePath, Resource location) throws IOException {
+		Resource resource = location.createRelative(resourcePath);
+		if (resource.exists() && resource.isReadable()) {
+			if (checkResource(resource, location)) {
+				return resource;
+			}
+			else if (logger.isTraceEnabled()) {
+				logger.trace("Resource path=\"" + resourcePath + "\" was successfully resolved " +
+						"but resource=\"" +	resource.getURL() + "\" is neither under the " +
+						"current location=\"" + location.getURL() + "\" nor under any of the " +
+						"allowed locations=" + Arrays.asList(getAllowedLocations()));
+			}
+		}
+		return null;
+	}
+
+	/**
+	 * Perform additional checks on a resolved resource beyond checking whether the
+	 * resources exists and is readable. The default implementation also verifies
+	 * the resource is either under the location relative to which it was found or
+	 * is under one of the {@link #setAllowedLocations allowed locations}.
+	 * @param resource the resource to check
+	 * @param location the location relative to which the resource was found
+	 * @return "true" if resource is in a valid location, "false" otherwise.
+	 */
+	protected boolean checkResource(Resource resource, Resource location) throws IOException {
+		if (isResourceUnderLocation(resource, location)) {
+			return true;
+		}
+		if (getAllowedLocations() != null) {
+			for (Resource current : getAllowedLocations()) {
+				if (isResourceUnderLocation(resource, current)) {
+					return true;
+				}
+			}
+		}
+		return false;
+	}
+
+	private boolean isResourceUnderLocation(Resource resource, Resource location) throws IOException {
+		if (resource.getClass() != location.getClass()) {
+			return false;
+		}
+
+		String resourcePath;
+		String locationPath;
+
+		if (resource instanceof UrlResource) {
+			resourcePath = resource.getURL().toExternalForm();
+			locationPath = StringUtils.cleanPath(location.getURL().toString());
+		}
+		else if (resource instanceof ClassPathResource) {
+			resourcePath = ((ClassPathResource) resource).getPath();
+			locationPath = StringUtils.cleanPath(((ClassPathResource) location).getPath());
+		}
+		else {
+			resourcePath = resource.getURL().getPath();
+			locationPath = StringUtils.cleanPath(location.getURL().getPath());
+		}
+
+		if (locationPath.equals(resourcePath)) {
+			return true;
+		}
+		locationPath = (locationPath.endsWith("/") || locationPath.isEmpty() ? locationPath : locationPath + "/");
+		if (!resourcePath.startsWith(locationPath)) {
+			return false;
+		}
+
+		if (resourcePath.contains("%")) {
+			// Use URLDecoder (vs UriUtils) to preserve potentially decoded UTF-8 chars...
+			if (URLDecoder.decode(resourcePath, "UTF-8").contains("../")) {
+				if (logger.isTraceEnabled()) {
+					logger.trace("Resolved resource path contains \"../\" after decoding: " + resourcePath);
+				}
+				return false;
+			}
+		}
+
+		return true;
+	}
+
+}

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

@@ -0,0 +1,60 @@
+/*
+ * 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.
+ * 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.resource;
+
+import java.util.List;
+
+import org.springframework.core.io.Resource;
+import org.springframework.web.server.ServerWebExchange;
+
+/**
+ * A strategy for resolving a request to a server-side resource.
+ *
+ * <p>Provides mechanisms for resolving an incoming request to an actual
+ * {@link Resource} and for obtaining the
+ * public URL path that clients should use when requesting the resource.
+ *
+ * @author Rossen Stoyanchev
+ * @since 5.0
+ */
+public interface ResourceResolver {
+
+	/**
+	 * Resolve the supplied request and request path to a {@link Resource} that
+	 * exists under one of the given resource locations.
+	 * @param exchange the current exchange
+	 * @param requestPath the portion of the request path to use
+	 * @param locations the locations to search in when looking up resources
+	 * @param chain the chain of remaining resolvers to delegate to
+	 * @return the resolved resource or {@code null} if unresolved
+	 */
+	Resource resolveResource(ServerWebExchange exchange, String requestPath, List<? extends Resource> locations,
+			ResourceResolverChain chain);
+
+	/**
+	 * Resolve the externally facing <em>public</em> URL path for clients to use
+	 * to access the resource that is located at the given <em>internal</em>
+	 * resource path.
+	 * <p>This is useful when rendering URL links to clients.
+	 * @param resourcePath the internal resource path
+	 * @param locations the locations to search in when looking up resources
+	 * @param chain the chain of resolvers to delegate to
+	 * @return the resolved public URL path or {@code null} if unresolved
+	 */
+	String resolveUrlPath(String resourcePath, List<? extends Resource> locations, ResourceResolverChain chain);
+
+}

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

@@ -0,0 +1,54 @@
+/*
+ * 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.
+ * 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.resource;
+
+import java.util.List;
+
+import org.springframework.core.io.Resource;
+import org.springframework.web.server.ServerWebExchange;
+
+/**
+ * A contract for invoking a chain of {@link ResourceResolver}s where each resolver
+ * is given a reference to the chain allowing it to delegate when necessary.
+ *
+ * @author Rossen Stoyanchev
+ * @since 5.0
+ */
+public interface ResourceResolverChain {
+
+	/**
+	 * Resolve the supplied request and request path to a {@link Resource} that
+	 * exists under one of the given resource locations.
+	 * @param exchange the current exchange
+	 * @param requestPath the portion of the request path to use
+	 * @param locations the locations to search in when looking up resources
+	 * @return the resolved resource or {@code null} if unresolved
+	 */
+	Resource resolveResource(ServerWebExchange exchange, String requestPath, List<? extends Resource> locations);
+
+	/**
+	 * Resolve the externally facing <em>public</em> URL path for clients to use
+	 * to access the resource that is located at the given <em>internal</em>
+	 * resource path.
+	 * <p>This is useful when rendering URL links to clients.
+	 * @param resourcePath the internal resource path
+	 * @param locations the locations to search in when looking up resources
+	 * @return the resolved public URL path or {@code null} if unresolved
+	 */
+	String resolveUrlPath(String resourcePath, List<? extends Resource> locations);
+
+}

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

@@ -0,0 +1,44 @@
+/*
+ * 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.
+ * 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.resource;
+
+import java.io.IOException;
+
+import org.springframework.core.io.Resource;
+import org.springframework.web.server.ServerWebExchange;
+
+/**
+ * An abstraction for transforming the content of a resource.
+ *
+ * @author Rossen Stoyanchev
+ * @since 5.0
+ */
+@FunctionalInterface
+public interface ResourceTransformer {
+
+	/**
+	 * Transform the given resource.
+	 * @param exchange the current exchange
+	 * @param resource the resource to transform
+	 * @param transformerChain the chain of remaining transformers to delegate to
+	 * @return the transformed resource (never {@code null})
+	 * @throws IOException if the transformation fails
+	 */
+	Resource transform(ServerWebExchange exchange, Resource resource,
+			ResourceTransformerChain transformerChain) throws IOException;
+
+}

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

@@ -0,0 +1,49 @@
+/*
+ * 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.
+ * 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.resource;
+
+import java.io.IOException;
+
+import org.springframework.core.io.Resource;
+import org.springframework.web.server.ServerWebExchange;
+
+/**
+ * A contract for invoking a chain of {@link ResourceTransformer}s where each resolver
+ * is given a reference to the chain allowing it to delegate when necessary.
+ *
+ * @author Rossen Stoyanchev
+ * @since 5.0
+ */
+public interface ResourceTransformerChain {
+
+	/**
+	 * Return the {@code ResourceResolverChain} that was used to resolve the
+	 * {@code Resource} being transformed. This may be needed for resolving
+	 * related resources, e.g. links to other resources.
+	 */
+	ResourceResolverChain getResolverChain();
+
+	/**
+	 * Transform the given resource.
+	 * @param exchange the current exchange
+	 * @param resource the candidate resource to transform
+	 * @return the transformed or the same resource, never {@code null}
+	 * @throws IOException if transformation fails
+	 */
+	Resource transform(ServerWebExchange exchange, Resource resource) throws IOException;
+
+}

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

@@ -0,0 +1,82 @@
+/*
+ * 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.
+ * 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.resource;
+
+import java.util.Collections;
+
+import org.springframework.core.io.Resource;
+import org.springframework.web.server.ServerWebExchange;
+
+/**
+ * A base class for a {@code ResourceTransformer} with an optional helper method
+ * for resolving public links within a transformed resource.
+ *
+ * @author Rossen Stoyanchev
+ * @author Brian Clozel
+ * @since 5.0
+ */
+public abstract class ResourceTransformerSupport implements ResourceTransformer {
+
+	private ResourceUrlProvider resourceUrlProvider;
+
+
+	/**
+	 * Configure a {@link ResourceUrlProvider} to use when resolving the public
+	 * URL of links in a transformed resource (e.g. import links in a CSS file).
+	 * This is required only for links expressed as full paths and not for
+	 * relative links.
+	 * @param resourceUrlProvider the URL provider to use
+	 */
+	public void setResourceUrlProvider(ResourceUrlProvider resourceUrlProvider) {
+		this.resourceUrlProvider = resourceUrlProvider;
+	}
+
+	/**
+	 * @return the configured {@code ResourceUrlProvider}.
+	 */
+	public ResourceUrlProvider getResourceUrlProvider() {
+		return this.resourceUrlProvider;
+	}
+
+
+	/**
+	 * A transformer can use this method when a resource being transformed
+	 * contains links to other resources. Such links need to be replaced with the
+	 * public facing link as determined by the resource resolver chain (e.g. the
+	 * public URL may have a version inserted).
+	 * @param resourcePath the path to a resource that needs to be re-written
+	 * @param exchange the current exchange
+	 * @param resource the resource being transformed
+	 * @param transformerChain the transformer chain
+	 * @return the resolved URL or null
+	 */
+	protected String resolveUrlPath(String resourcePath, ServerWebExchange exchange,
+			Resource resource, ResourceTransformerChain transformerChain) {
+
+		if (resourcePath.startsWith("/")) {
+			// full resource path
+			ResourceUrlProvider urlProvider = getResourceUrlProvider();
+			return (urlProvider != null ? urlProvider.getForRequestUrl(exchange, resourcePath) : null);
+		}
+		else {
+			// try resolving as relative path
+			return transformerChain.getResolverChain()
+					.resolveUrlPath(resourcePath, Collections.singletonList(resource));
+		}
+	}
+
+}

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

@@ -0,0 +1,247 @@
+/*
+ * 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.
+ * 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.resource;
+
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.Comparator;
+import java.util.LinkedHashMap;
+import java.util.List;
+import java.util.Map;
+
+import org.apache.commons.logging.Log;
+import org.apache.commons.logging.LogFactory;
+
+import org.springframework.context.ApplicationContext;
+import org.springframework.context.ApplicationListener;
+import org.springframework.context.event.ContextRefreshedEvent;
+import org.springframework.core.annotation.AnnotationAwareOrderComparator;
+import org.springframework.http.server.reactive.ServerHttpRequest;
+import org.springframework.util.AntPathMatcher;
+import org.springframework.util.PathMatcher;
+import org.springframework.web.reactive.handler.SimpleUrlHandlerMapping;
+import org.springframework.web.server.ServerWebExchange;
+import org.springframework.web.util.HttpRequestPathHelper;
+
+/**
+ * A central component to use to obtain the public URL path that clients should
+ * use to access a static resource.
+ *
+ * <p>This class is aware of Spring MVC handler mappings used to serve static
+ * resources and uses the {@code ResourceResolver} chains of the configured
+ * {@code ResourceHttpRequestHandler}s to make its decisions.
+ *
+ * @author Rossen Stoyanchev
+ * @since 5.0
+ */
+public class ResourceUrlProvider implements ApplicationListener<ContextRefreshedEvent> {
+
+	protected final Log logger = LogFactory.getLog(getClass());
+
+	private HttpRequestPathHelper urlPathHelper = new HttpRequestPathHelper();
+
+	private PathMatcher pathMatcher = new AntPathMatcher();
+
+	private final Map<String, ResourceWebHandler> handlerMap = new LinkedHashMap<>();
+
+	private boolean autodetect = true;
+
+
+	/**
+	 * Configure a {@code UrlPathHelper} to use in
+	 * {@link #getForRequestUrl(ServerWebExchange, String)}
+	 * in order to derive the lookup path for a target request URL path.
+	 */
+	public void setUrlPathHelper(HttpRequestPathHelper urlPathHelper) {
+		this.urlPathHelper = urlPathHelper;
+	}
+
+	/**
+	 * Return the configured {@code UrlPathHelper}.
+	 */
+	public HttpRequestPathHelper getUrlPathHelper() {
+		return this.urlPathHelper;
+	}
+
+	/**
+	 * Configure a {@code PathMatcher} to use when comparing target lookup path
+	 * against resource mappings.
+	 */
+	public void setPathMatcher(PathMatcher pathMatcher) {
+		this.pathMatcher = pathMatcher;
+	}
+
+	/**
+	 * Return the configured {@code PathMatcher}.
+	 */
+	public PathMatcher getPathMatcher() {
+		return this.pathMatcher;
+	}
+
+	/**
+	 * Manually configure the resource mappings.
+	 * <p><strong>Note:</strong> by default resource mappings are auto-detected
+	 * from the Spring {@code ApplicationContext}. However if this property is
+	 * used, the auto-detection is turned off.
+	 */
+	public void setHandlerMap(Map<String, ResourceWebHandler> handlerMap) {
+		if (handlerMap != null) {
+			this.handlerMap.clear();
+			this.handlerMap.putAll(handlerMap);
+			this.autodetect = false;
+		}
+	}
+
+	/**
+	 * Return the resource mappings, either manually configured or auto-detected
+	 * when the Spring {@code ApplicationContext} is refreshed.
+	 */
+	public Map<String, ResourceWebHandler> getHandlerMap() {
+		return this.handlerMap;
+	}
+
+	/**
+	 * Return {@code false} if resource mappings were manually configured,
+	 * {@code true} otherwise.
+	 */
+	public boolean isAutodetect() {
+		return this.autodetect;
+	}
+
+	@Override
+	public void onApplicationEvent(ContextRefreshedEvent event) {
+		if (isAutodetect()) {
+			this.handlerMap.clear();
+			detectResourceHandlers(event.getApplicationContext());
+			if (this.handlerMap.isEmpty() && logger.isDebugEnabled()) {
+				logger.debug("No resource handling mappings found");
+			}
+			if (!this.handlerMap.isEmpty()) {
+				this.autodetect = false;
+			}
+		}
+	}
+
+
+	protected void detectResourceHandlers(ApplicationContext appContext) {
+		logger.debug("Looking for resource handler mappings");
+
+		Map<String, SimpleUrlHandlerMapping> map = appContext.getBeansOfType(SimpleUrlHandlerMapping.class);
+		List<SimpleUrlHandlerMapping> handlerMappings = new ArrayList<>(map.values());
+		AnnotationAwareOrderComparator.sort(handlerMappings);
+
+		for (SimpleUrlHandlerMapping hm : handlerMappings) {
+			for (String pattern : hm.getHandlerMap().keySet()) {
+				Object handler = hm.getHandlerMap().get(pattern);
+				if (handler instanceof ResourceWebHandler) {
+					ResourceWebHandler resourceHandler = (ResourceWebHandler) handler;
+					if (logger.isDebugEnabled()) {
+						logger.debug("Found resource handler mapping: URL pattern=\"" + pattern + "\", " +
+								"locations=" + resourceHandler.getLocations() + ", " +
+								"resolvers=" + resourceHandler.getResourceResolvers());
+					}
+					this.handlerMap.put(pattern, resourceHandler);
+				}
+			}
+		}
+	}
+
+	/**
+	 * A variation on {@link #getForLookupPath(String)} that accepts a full request
+	 * URL path and returns the full request URL path to expose for public use.
+	 * @param exchange the current exchange
+	 * @param requestUrl the request URL path to resolve
+	 * @return the resolved public URL path, or {@code null} if unresolved
+	 */
+	public final String getForRequestUrl(ServerWebExchange exchange, String requestUrl) {
+		if (logger.isTraceEnabled()) {
+			logger.trace("Getting resource URL for request URL \"" + requestUrl + "\"");
+		}
+		int prefixIndex = getLookupPathIndex(exchange);
+		int suffixIndex = getQueryParamsIndex(requestUrl);
+		String prefix = requestUrl.substring(0, prefixIndex);
+		String suffix = requestUrl.substring(suffixIndex);
+		String lookupPath = requestUrl.substring(prefixIndex, suffixIndex);
+		String resolvedLookupPath = getForLookupPath(lookupPath);
+		return (resolvedLookupPath != null ? prefix + resolvedLookupPath + suffix : null);
+	}
+
+	private int getLookupPathIndex(ServerWebExchange exchange) {
+		ServerHttpRequest request = exchange.getRequest();
+		String requestPath = request.getURI().getPath();
+		String lookupPath = getUrlPathHelper().getLookupPathForRequest(exchange);
+		return requestPath.indexOf(lookupPath);
+	}
+
+	private int getQueryParamsIndex(String lookupPath) {
+		int index = lookupPath.indexOf("?");
+		return index > 0 ? index : lookupPath.length();
+	}
+
+	/**
+	 * Compare the given path against configured resource handler mappings and
+	 * if a match is found use the {@code ResourceResolver} chain of the matched
+	 * {@code ResourceHttpRequestHandler} to resolve the URL path to expose for
+	 * public use.
+	 * <p>It is expected that the given path is what Spring uses for
+	 * request mapping purposes.
+	 * <p>If several handler mappings match, the handler used will be the one
+	 * configured with the most specific pattern.
+	 * @param lookupPath the lookup path to check
+	 * @return the resolved public URL path, or {@code null} if unresolved
+	 */
+	public final String getForLookupPath(String lookupPath) {
+		if (logger.isTraceEnabled()) {
+			logger.trace("Getting resource URL for lookup path \"" + lookupPath + "\"");
+		}
+
+		List<String> matchingPatterns = new ArrayList<>();
+		for (String pattern : this.handlerMap.keySet()) {
+			if (getPathMatcher().match(pattern, lookupPath)) {
+				matchingPatterns.add(pattern);
+			}
+		}
+
+		if (!matchingPatterns.isEmpty()) {
+			Comparator<String> patternComparator = getPathMatcher().getPatternComparator(lookupPath);
+			Collections.sort(matchingPatterns, patternComparator);
+			for (String pattern : matchingPatterns) {
+				String pathWithinMapping = getPathMatcher().extractPathWithinPattern(pattern, lookupPath);
+				String pathMapping = lookupPath.substring(0, lookupPath.indexOf(pathWithinMapping));
+				if (logger.isTraceEnabled()) {
+					logger.trace("Invoking ResourceResolverChain for URL pattern \"" + pattern + "\"");
+				}
+				ResourceWebHandler handler = this.handlerMap.get(pattern);
+				ResourceResolverChain chain = new DefaultResourceResolverChain(handler.getResourceResolvers());
+				String resolved = chain.resolveUrlPath(pathWithinMapping, handler.getLocations());
+				if (resolved == null) {
+					continue;
+				}
+				if (logger.isTraceEnabled()) {
+					logger.trace("Resolved public resource URL path \"" + resolved + "\"");
+				}
+				return pathMapping + resolved;
+			}
+		}
+
+		if (logger.isDebugEnabled()) {
+			logger.debug("No matching resource mapping for lookup path \"" + lookupPath + "\"");
+		}
+		return null;
+	}
+
+}

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

@@ -0,0 +1,500 @@
+/*
+ * 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.
+ * 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.resource;
+
+import java.io.IOException;
+import java.net.URLDecoder;
+import java.time.Instant;
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.HashMap;
+import java.util.LinkedHashSet;
+import java.util.List;
+import java.util.Map;
+import java.util.Optional;
+import java.util.Set;
+
+import org.apache.commons.logging.Log;
+import org.apache.commons.logging.LogFactory;
+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.codec.ResourceHttpMessageWriter;
+import org.springframework.util.Assert;
+import org.springframework.util.CollectionUtils;
+import org.springframework.util.ObjectUtils;
+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;
+
+/**
+ * {@code HttpRequestHandler} that serves static resources in an optimized way
+ * according to the guidelines of Page Speed, YSlow, etc.
+ *
+ * <p>The {@linkplain #setLocations "locations"} property takes a list of Spring
+ * {@link Resource} locations from which static resources are allowed to
+ * be served by this handler. Resources could be served from a classpath location,
+ * e.g. "classpath:/META-INF/public-web-resources/", allowing convenient packaging
+ * and serving of resources such as .js, .css, and others in jar files.
+ *
+ * <p>This request handler may also be configured with a
+ * {@link #setResourceResolvers(List) resourcesResolver} and
+ * {@link #setResourceTransformers(List) resourceTransformer} chains to support
+ * arbitrary resolution and transformation of resources being served. By default a
+ * {@link PathResourceResolver} simply finds resources based on the configured
+ * "locations". An application can configure additional resolvers and
+ * transformers such as the {@link VersionResourceResolver} which can resolve
+ * and prepare URLs for resources with a version in the URL.
+ *
+ * <p>This handler also properly evaluates the {@code Last-Modified} header (if
+ * present) so that a {@code 304} status code will be returned as appropriate,
+ * avoiding unnecessary overhead for resources that are already cached by the
+ * client.
+ *
+ * @author Rossen Stoyanchev
+ * @since 5.0
+ */
+public class ResourceWebHandler
+		implements WebHandler, InitializingBean, SmartInitializingSingleton {
+
+	/** Set of supported HTTP methods */
+	private static final Set<String> SUPPORTED_METHODS = new LinkedHashSet<>(2);
+
+	private static final Log logger = LogFactory.getLog(ResourceWebHandler.class);
+
+	static {
+		SUPPORTED_METHODS.addAll(Arrays.asList("GET", "HEAD"));
+	}
+
+
+	private final List<Resource> locations = new ArrayList<>(4);
+
+	private final List<ResourceResolver> resourceResolvers = new ArrayList<>(4);
+
+	private final List<ResourceTransformer> resourceTransformers = new ArrayList<>(4);
+
+	private CacheControl cacheControl;
+
+	private ResourceHttpMessageWriter resourceHttpMessageWriter;
+
+	private CompositeContentTypeResolver contentTypeResolver;
+
+	private PathExtensionContentTypeResolver pathExtensionResolver;
+
+
+	/**
+	 * Set the {@code List} of {@code Resource} paths to use as sources
+	 * for serving static resources.
+	 */
+	public void setLocations(List<Resource> locations) {
+		Assert.notNull(locations, "Locations list must not be null");
+		this.locations.clear();
+		this.locations.addAll(locations);
+	}
+
+	/**
+	 * Return the {@code List} of {@code Resource} paths to use as sources
+	 * for serving static resources.
+	 */
+	public List<Resource> getLocations() {
+		return this.locations;
+	}
+
+	/**
+	 * Configure the list of {@link ResourceResolver}s to use.
+	 * <p>By default {@link PathResourceResolver} is configured. If using this property,
+	 * it is recommended to add {@link PathResourceResolver} as the last resolver.
+	 */
+	public void setResourceResolvers(List<ResourceResolver> resourceResolvers) {
+		this.resourceResolvers.clear();
+		if (resourceResolvers != null) {
+			this.resourceResolvers.addAll(resourceResolvers);
+		}
+	}
+
+	/**
+	 * Return the list of configured resource resolvers.
+	 */
+	public List<ResourceResolver> getResourceResolvers() {
+		return this.resourceResolvers;
+	}
+
+	/**
+	 * Configure the list of {@link ResourceTransformer}s to use.
+	 * <p>By default no transformers are configured for use.
+	 */
+	public void setResourceTransformers(List<ResourceTransformer> resourceTransformers) {
+		this.resourceTransformers.clear();
+		if (resourceTransformers != null) {
+			this.resourceTransformers.addAll(resourceTransformers);
+		}
+	}
+
+	/**
+	 * Return the list of configured resource transformers.
+	 */
+	public List<ResourceTransformer> getResourceTransformers() {
+		return this.resourceTransformers;
+	}
+
+	/**
+	 * Set the {@link org.springframework.http.CacheControl} instance to build
+	 * the Cache-Control HTTP response header.
+	 */
+	public void setCacheControl(CacheControl cacheControl) {
+		this.cacheControl = cacheControl;
+	}
+
+	public CacheControl getCacheControl() {
+		return this.cacheControl;
+	}
+
+	/**
+	 * Configure the {@link ResourceHttpMessageWriter} to use.
+	 * <p>By default a {@link ResourceHttpMessageWriter} will be configured.
+	 */
+	public void setResourceHttpMessageWriter(ResourceHttpMessageWriter httpMessageWriter) {
+		this.resourceHttpMessageWriter = httpMessageWriter;
+	}
+
+	/**
+	 * Return the list of configured resource converters.
+	 */
+	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}.
+	 */
+	public CompositeContentTypeResolver getContentTypeResolver() {
+		return this.contentTypeResolver;
+	}
+
+	@Override
+	public void afterPropertiesSet() throws Exception {
+		if (logger.isWarnEnabled() && CollectionUtils.isEmpty(this.locations)) {
+			logger.warn("Locations list is empty. No resources will be served unless a " +
+					"custom ResourceResolver is configured as an alternative to PathResourceResolver.");
+		}
+		if (this.resourceResolvers.isEmpty()) {
+			this.resourceResolvers.add(new PathResourceResolver());
+		}
+		initAllowedLocations();
+		if (this.resourceHttpMessageWriter == null) {
+			this.resourceHttpMessageWriter = new ResourceHttpMessageWriter();
+		}
+	}
+
+	/**
+	 * Look for a {@code PathResourceResolver} among the configured resource
+	 * resolvers and set its {@code allowedLocations} property (if empty) to
+	 * match the {@link #setLocations locations} configured on this class.
+	 */
+	protected void initAllowedLocations() {
+		if (CollectionUtils.isEmpty(this.locations)) {
+			return;
+		}
+		for (int i = getResourceResolvers().size() - 1; i >= 0; i--) {
+			if (getResourceResolvers().get(i) instanceof PathResourceResolver) {
+				PathResourceResolver resolver = (PathResourceResolver) getResourceResolvers().get(i);
+				if (ObjectUtils.isEmpty(resolver.getAllowedLocations())) {
+					resolver.setAllowedLocations(getLocations().toArray(new Resource[getLocations().size()]));
+				}
+				break;
+			}
+		}
+	}
+
+	@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.
+	 * <p>Checks for the existence of the requested resource in the configured list of locations.
+	 * If the resource does not exist, a {@code 404} response will be returned to the client.
+	 * If the resource exists, the request will be checked for the presence of the
+	 * {@code Last-Modified} header, and its value will be compared against the last-modified
+	 * timestamp of the given resource, returning a {@code 304} status code if the
+	 * {@code Last-Modified} value  is greater. If the resource is newer than the
+	 * {@code Last-Modified} value, or the header is not present, the content resource
+	 * of the resource will be written to the response with caching headers
+	 * set to expire one year in the future.
+	 */
+	@Override
+	public Mono<Void> handle(ServerWebExchange exchange) {
+		try {
+			// For very general mappings (e.g. "/") we need to check 404 first
+			Resource resource = getResource(exchange);
+			if (resource == null) {
+				logger.trace("No matching resource found - returning 404");
+				exchange.getResponse().setStatusCode(HttpStatus.NOT_FOUND);
+				return Mono.empty();
+			}
+
+			if (HttpMethod.OPTIONS.equals(exchange.getRequest().getMethod())) {
+				exchange.getResponse().getHeaders().add("Allow", "GET,HEAD,OPTIONS");
+				return Mono.empty();
+			}
+
+			// Supported methods and required session
+			String httpMehtod = exchange.getRequest().getMethod().name();
+			if (!SUPPORTED_METHODS.contains(httpMehtod)) {
+				return Mono.error(new MethodNotAllowedException(httpMehtod, SUPPORTED_METHODS));
+			}
+
+			// Header phase
+			if (exchange.checkNotModified(Instant.ofEpochMilli(resource.lastModified()))) {
+				logger.trace("Resource not modified - returning 304");
+				return Mono.empty();
+			}
+
+			// Apply cache settings, if any
+			if (getCacheControl() != null) {
+				String value = getCacheControl().getHeaderValue();
+				if (value != null) {
+					exchange.getResponse().getHeaders().setCacheControl(value);
+				}
+			}
+
+			// Check the media type for the resource
+			MediaType mediaType = getMediaType(exchange, resource);
+			if (mediaType != null) {
+				if (logger.isTraceEnabled()) {
+					logger.trace("Determined media type '" + mediaType + "' for " + resource);
+				}
+			}
+			else {
+				if (logger.isTraceEnabled()) {
+					logger.trace("No media type found for " + resource + " - not sending a content-type header");
+				}
+			}
+
+			// Content phase
+			if (HttpMethod.HEAD.equals(exchange.getRequest().getMethod())) {
+				setHeaders(exchange, resource, mediaType);
+				logger.trace("HEAD request - skipping content");
+				return Mono.empty();
+			}
+
+			// TODO: range requests
+
+			setHeaders(exchange, resource, mediaType);
+			return this.resourceHttpMessageWriter.write(Mono.just(resource),
+					ResolvableType.forClass(Resource.class), mediaType, exchange.getResponse());
+		}
+		catch (IOException ex) {
+			return Mono.error(ex);
+		}
+	}
+
+	protected Resource getResource(ServerWebExchange exchange) throws IOException {
+		String attrName = HandlerMapping.PATH_WITHIN_HANDLER_MAPPING_ATTRIBUTE;
+		Optional<String> optional = exchange.getAttribute(attrName);
+		if (!optional.isPresent()) {
+			throw new IllegalStateException("Required request attribute '" + attrName + "' is not set");
+		}
+		String path = processPath(optional.get());
+		if (!StringUtils.hasText(path) || isInvalidPath(path)) {
+			if (logger.isTraceEnabled()) {
+				logger.trace("Ignoring invalid resource path [" + path + "]");
+			}
+			return null;
+		}
+		if (path.contains("%")) {
+			try {
+				// Use URLDecoder (vs UriUtils) to preserve potentially decoded UTF-8 chars
+				if (isInvalidPath(URLDecoder.decode(path, "UTF-8"))) {
+					if (logger.isTraceEnabled()) {
+						logger.trace("Ignoring invalid resource path with escape sequences [" + path + "].");
+					}
+					return null;
+				}
+			}
+			catch (IllegalArgumentException ex) {
+				// ignore
+			}
+		}
+		ResourceResolverChain resolveChain = new DefaultResourceResolverChain(getResourceResolvers());
+		Resource resource = resolveChain.resolveResource(exchange, path, getLocations());
+		if (resource == null || getResourceTransformers().isEmpty()) {
+			return resource;
+		}
+
+		ResourceTransformerChain transformChain =
+				new DefaultResourceTransformerChain(resolveChain, getResourceTransformers());
+		resource = transformChain.transform(exchange, resource);
+		return resource;
+	}
+
+	/**
+	 * Process the given resource path to be used.
+	 * <p>The default implementation replaces any combination of leading '/' and
+	 * control characters (00-1F and 7F) with a single "/" or "". For example
+	 * {@code "  // /// ////  foo/bar"} becomes {@code "/foo/bar"}.
+	 */
+	protected String processPath(String path) {
+		boolean slash = false;
+		for (int i = 0; i < path.length(); i++) {
+			if (path.charAt(i) == '/') {
+				slash = true;
+			}
+			else if (path.charAt(i) > ' ' && path.charAt(i) != 127) {
+				if (i == 0 || (i == 1 && slash)) {
+					return path;
+				}
+				path = slash ? "/" + path.substring(i) : path.substring(i);
+				if (logger.isTraceEnabled()) {
+					logger.trace("Path after trimming leading '/' and control characters: " + path);
+				}
+				return path;
+			}
+		}
+		return (slash ? "/" : "");
+	}
+
+	/**
+	 * Identifies invalid resource paths. By default rejects:
+	 * <ul>
+	 * <li>Paths that contain "WEB-INF" or "META-INF"
+	 * <li>Paths that contain "../" after a call to
+	 * {@link StringUtils#cleanPath}.
+	 * <li>Paths that represent a {@link ResourceUtils#isUrl
+	 * valid URL} or would represent one after the leading slash is removed.
+	 * </ul>
+	 * <p><strong>Note:</strong> this method assumes that leading, duplicate '/'
+	 * or control characters (e.g. white space) have been trimmed so that the
+	 * path starts predictably with a single '/' or does not have one.
+	 * @param path the path to validate
+	 * @return {@code true} if the path is invalid, {@code false} otherwise
+	 */
+	protected boolean isInvalidPath(String path) {
+		if (logger.isTraceEnabled()) {
+			logger.trace("Applying \"invalid path\" checks to path: " + path);
+		}
+		if (path.contains("WEB-INF") || path.contains("META-INF")) {
+			if (logger.isTraceEnabled()) {
+				logger.trace("Path contains \"WEB-INF\" or \"META-INF\".");
+			}
+			return true;
+		}
+		if (path.contains(":/")) {
+			String relativePath = (path.charAt(0) == '/' ? path.substring(1) : path);
+			if (ResourceUtils.isUrl(relativePath) || relativePath.startsWith("url:")) {
+				if (logger.isTraceEnabled()) {
+					logger.trace("Path represents URL or has \"url:\" prefix.");
+				}
+				return true;
+			}
+		}
+		if (path.contains("..")) {
+			path = StringUtils.cleanPath(path);
+			if (path.contains("../")) {
+				if (logger.isTraceEnabled()) {
+					logger.trace("Path contains \"../\" after call to StringUtils#cleanPath.");
+				}
+				return true;
+			}
+		}
+		return false;
+	}
+
+	/**
+	 * 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
+	 */
+	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
+	 * @param resource the identified resource (never {@code null})
+	 * @param mediaType the resource's media type (never {@code null})
+	 * @throws IOException in case of errors while setting the headers
+	 */
+	protected void setHeaders(ServerWebExchange exchange, Resource resource, MediaType mediaType)
+			throws IOException {
+
+		HttpHeaders headers = exchange.getResponse().getHeaders();
+
+		long length = resource.contentLength();
+		headers.setContentLength(length);
+
+		if (mediaType != null) {
+			headers.setContentType(mediaType);
+		}
+		if (resource instanceof EncodedResource) {
+			headers.set(HttpHeaders.CONTENT_ENCODING, ((EncodedResource) resource).getContentEncoding());
+		}
+		if (resource instanceof VersionedResource) {
+			headers.setETag("\"" + ((VersionedResource) resource).getVersion() + "\"");
+		}
+		headers.set(HttpHeaders.ACCEPT_RANGES, "bytes");
+	}
+
+
+	@Override
+	public String toString() {
+		return "ResourceWebHandler [locations=" + getLocations() + ", resolvers=" + getResourceResolvers() + "]";
+	}
+
+}

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

@@ -0,0 +1,62 @@
+/*
+ * 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.
+ * 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.resource;
+
+import java.io.IOException;
+
+import org.springframework.core.io.ByteArrayResource;
+import org.springframework.core.io.Resource;
+
+/**
+ * An extension of {@link ByteArrayResource}
+ * that a {@link ResourceTransformer} can use to represent an original
+ * resource preserving all other information except the content.
+ *
+ * @author Rossen Stoyanchev
+ * @since 5.0
+ */
+public class TransformedResource extends ByteArrayResource {
+
+	private final String filename;
+
+	private final long lastModified;
+
+
+	public TransformedResource(Resource original, byte[] transformedContent) {
+		super(transformedContent);
+		this.filename = original.getFilename();
+		try {
+			this.lastModified = original.lastModified();
+		}
+		catch (IOException ex) {
+			// should never happen
+			throw new IllegalArgumentException(ex);
+		}
+	}
+
+
+	@Override
+	public String getFilename() {
+		return this.filename;
+	}
+
+	@Override
+	public long lastModified() throws IOException {
+		return this.lastModified;
+	}
+
+}

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

@@ -0,0 +1,52 @@
+/*
+ * 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.
+ * 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.resource;
+
+/**
+ * A strategy for extracting and embedding a resource version in its URL path.
+ *
+ * @author Rossen Stoyanchev
+ * @author Brian Clozel
+ * @since 5.0
+*/
+public interface VersionPathStrategy {
+
+	/**
+	 * Extract the resource version from the request path.
+	 * @param requestPath the request path to check
+	 * @return the version string or {@code null} if none was found
+	 */
+	String extractVersion(String requestPath);
+
+	/**
+	 * Remove the version from the request path. It is assumed that the given
+	 * version was extracted via {@link #extractVersion(String)}.
+	 * @param requestPath the request path of the resource being resolved
+	 * @param version the version obtained from {@link #extractVersion(String)}
+	 * @return the request path with the version removed
+	 */
+	String removeVersion(String requestPath, String version);
+
+	/**
+	 * Add a version to the given request path.
+	 * @param requestPath the requestPath
+	 * @param version the version
+	 * @return the requestPath updated with a version string
+	 */
+	String addVersion(String requestPath, String version);
+
+}

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

@@ -0,0 +1,326 @@
+/*
+ * 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.
+ * 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.resource;
+
+import java.io.File;
+import java.io.IOException;
+import java.io.InputStream;
+import java.net.URI;
+import java.net.URL;
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Collections;
+import java.util.Comparator;
+import java.util.LinkedHashMap;
+import java.util.List;
+import java.util.Map;
+
+import org.springframework.core.io.AbstractResource;
+import org.springframework.core.io.Resource;
+import org.springframework.util.AntPathMatcher;
+import org.springframework.util.StringUtils;
+import org.springframework.web.server.ServerWebExchange;
+
+/**
+ * Resolves request paths containing a version string that can be used as part
+ * of an HTTP caching strategy in which a resource is cached with a date in the
+ * distant future (e.g. 1 year) and cached until the version, and therefore the
+ * URL, is changed.
+ *
+ * <p>Different versioning strategies exist, and this resolver must be configured
+ * with one or more such strategies along with path mappings to indicate which
+ * strategy applies to which resources.
+ *
+ * <p>{@code ContentVersionStrategy} is a good default choice except in cases
+ * where it cannot be used. Most notably the {@code ContentVersionStrategy}
+ * cannot be combined with JavaScript module loaders. For such cases the
+ * {@code FixedVersionStrategy} is a better choice.
+ *
+ * <p>Note that using this resolver to serve CSS files means that the
+ * {@link CssLinkResourceTransformer} should also be used in order to modify
+ * links within CSS files to also contain the appropriate versions generated
+ * by this resolver.
+ *
+ * @author Rossen Stoyanchev
+ * @author Brian Clozel
+ * @since 5.0
+ * @see VersionStrategy
+ */
+public class VersionResourceResolver extends AbstractResourceResolver {
+
+	private AntPathMatcher pathMatcher = new AntPathMatcher();
+
+	/** Map from path pattern -> VersionStrategy */
+	private final Map<String, VersionStrategy> versionStrategyMap = new LinkedHashMap<>();
+
+
+	/**
+	 * Set a Map with URL paths as keys and {@code VersionStrategy} as values.
+	 * <p>Supports direct URL matches and Ant-style pattern matches. For syntax
+	 * details, see the {@link AntPathMatcher} javadoc.
+	 * @param map map with URLs as keys and version strategies as values
+	 */
+	public void setStrategyMap(Map<String, VersionStrategy> map) {
+		this.versionStrategyMap.clear();
+		this.versionStrategyMap.putAll(map);
+	}
+
+	/**
+	 * Return the map with version strategies keyed by path pattern.
+	 */
+	public Map<String, VersionStrategy> getStrategyMap() {
+		return this.versionStrategyMap;
+	}
+
+	/**
+	 * Insert a content-based version in resource URLs that match the given path
+	 * patterns. The version is computed from the content of the file, e.g.
+	 * {@code "css/main-e36d2e05253c6c7085a91522ce43a0b4.css"}. This is a good
+	 * default strategy to use except when it cannot be, for example when using
+	 * JavaScript module loaders, use {@link #addFixedVersionStrategy} instead
+	 * for serving JavaScript files.
+	 * @param pathPatterns one or more resource URL path patterns
+	 * @return the current instance for chained method invocation
+	 * @see ContentVersionStrategy
+	 */
+	public VersionResourceResolver addContentVersionStrategy(String... pathPatterns) {
+		addVersionStrategy(new ContentVersionStrategy(), pathPatterns);
+		return this;
+	}
+
+	/**
+	 * Insert a fixed, prefix-based version in resource URLs that match the given
+	 * path patterns, for example: <code>"{version}/js/main.js"</code>. This is useful (vs.
+	 * content-based versions) when using JavaScript module loaders.
+	 * <p>The version may be a random number, the current date, or a value
+	 * fetched from a git commit sha, a property file, or environment variable
+	 * and set with SpEL expressions in the configuration (e.g. see {@code @Value}
+	 * in Java config).
+	 * <p>If not done already, variants of the given {@code pathPatterns}, prefixed with
+	 * the {@code version} will be also configured. For example, adding a {@code "/js/**"} path pattern
+	 * will also cofigure automatically a {@code "/v1.0.0/js/**"} with {@code "v1.0.0"} the
+	 * {@code version} String given as an argument.
+	 * @param version a version string
+	 * @param pathPatterns one or more resource URL path patterns
+	 * @return the current instance for chained method invocation
+	 * @see FixedVersionStrategy
+	 */
+	public VersionResourceResolver addFixedVersionStrategy(String version, String... pathPatterns) {
+		List<String> patternsList = Arrays.asList(pathPatterns);
+		List<String> prefixedPatterns = new ArrayList<>(pathPatterns.length);
+		String versionPrefix = "/" + version;
+		for (String pattern : patternsList) {
+			prefixedPatterns.add(pattern);
+			if (!pattern.startsWith(versionPrefix) && !patternsList.contains(versionPrefix + pattern)) {
+				prefixedPatterns.add(versionPrefix + pattern);
+			}
+		}
+		return addVersionStrategy(new FixedVersionStrategy(version), prefixedPatterns.toArray(new String[0]));
+	}
+
+	/**
+	 * Register a custom VersionStrategy to apply to resource URLs that match the
+	 * given path patterns.
+	 * @param strategy the custom strategy
+	 * @param pathPatterns one or more resource URL path patterns
+	 * @return the current instance for chained method invocation
+	 * @see VersionStrategy
+	 */
+	public VersionResourceResolver addVersionStrategy(VersionStrategy strategy, String... pathPatterns) {
+		for (String pattern : pathPatterns) {
+			getStrategyMap().put(pattern, strategy);
+		}
+		return this;
+	}
+
+
+	@Override
+	protected Resource resolveResourceInternal(ServerWebExchange exchange, String requestPath,
+			List<? extends Resource> locations, ResourceResolverChain chain) {
+
+		Resource resolved = chain.resolveResource(exchange, requestPath, locations);
+		if (resolved != null) {
+			return resolved;
+		}
+
+		VersionStrategy versionStrategy = getStrategyForPath(requestPath);
+		if (versionStrategy == null) {
+			return null;
+		}
+
+		String candidateVersion = versionStrategy.extractVersion(requestPath);
+		if (StringUtils.isEmpty(candidateVersion)) {
+			if (logger.isTraceEnabled()) {
+				logger.trace("No version found in path \"" + requestPath + "\"");
+			}
+			return null;
+		}
+
+		String simplePath = versionStrategy.removeVersion(requestPath, candidateVersion);
+		if (logger.isTraceEnabled()) {
+			logger.trace("Extracted version from path, re-resolving without version: \"" + simplePath + "\"");
+		}
+
+		Resource baseResource = chain.resolveResource(exchange, simplePath, locations);
+		if (baseResource == null) {
+			return null;
+		}
+
+		String actualVersion = versionStrategy.getResourceVersion(baseResource);
+		if (candidateVersion.equals(actualVersion)) {
+			if (logger.isTraceEnabled()) {
+				logger.trace("Resource matches extracted version [" + candidateVersion + "]");
+			}
+			return new FileNameVersionedResource(baseResource, candidateVersion);
+		}
+		else {
+			if (logger.isTraceEnabled()) {
+				logger.trace("Potential resource found for \"" + requestPath + "\", but version [" +
+						candidateVersion + "] does not match");
+			}
+			return null;
+		}
+	}
+
+	@Override
+	protected String resolveUrlPathInternal(String resourceUrlPath, List<? extends Resource> locations,
+			ResourceResolverChain chain) {
+
+		String baseUrl = chain.resolveUrlPath(resourceUrlPath, locations);
+		if (StringUtils.hasText(baseUrl)) {
+			VersionStrategy versionStrategy = getStrategyForPath(resourceUrlPath);
+			if (versionStrategy == null) {
+				return null;
+			}
+			if (logger.isTraceEnabled()) {
+				logger.trace("Getting the original resource to determine version " +
+						"for path \"" + resourceUrlPath + "\"");
+			}
+			Resource resource = chain.resolveResource(null, baseUrl, locations);
+			String version = versionStrategy.getResourceVersion(resource);
+			if (logger.isTraceEnabled()) {
+				logger.trace("Determined version [" + version + "] for " + resource);
+			}
+			return versionStrategy.addVersion(baseUrl, version);
+		}
+		return baseUrl;
+	}
+
+	/**
+	 * Find a {@code VersionStrategy} for the request path of the requested resource.
+	 * @return an instance of a {@code VersionStrategy} or null if none matches that request path
+	 */
+	protected VersionStrategy getStrategyForPath(String requestPath) {
+		String path = "/".concat(requestPath);
+		List<String> matchingPatterns = new ArrayList<>();
+		for (String pattern : this.versionStrategyMap.keySet()) {
+			if (this.pathMatcher.match(pattern, path)) {
+				matchingPatterns.add(pattern);
+			}
+		}
+		if (!matchingPatterns.isEmpty()) {
+			Comparator<String> comparator = this.pathMatcher.getPatternComparator(path);
+			Collections.sort(matchingPatterns, comparator);
+			return this.versionStrategyMap.get(matchingPatterns.get(0));
+		}
+		return null;
+	}
+
+
+	private class FileNameVersionedResource extends AbstractResource implements VersionedResource {
+
+		private final Resource original;
+
+		private final String version;
+
+		public FileNameVersionedResource(Resource original, String version) {
+			this.original = original;
+			this.version = version;
+		}
+
+		@Override
+		public boolean exists() {
+			return this.original.exists();
+		}
+
+		@Override
+		public boolean isReadable() {
+			return this.original.isReadable();
+		}
+
+		@Override
+		public boolean isOpen() {
+			return this.original.isOpen();
+		}
+
+		@Override
+		public boolean isFile() {
+			return this.original.isFile();
+		}
+
+		@Override
+		public URL getURL() throws IOException {
+			return this.original.getURL();
+		}
+
+		@Override
+		public URI getURI() throws IOException {
+			return this.original.getURI();
+		}
+
+		@Override
+		public File getFile() throws IOException {
+			return this.original.getFile();
+		}
+
+		@Override
+		public String getFilename() {
+			return this.original.getFilename();
+		}
+
+		@Override
+		public long contentLength() throws IOException {
+			return this.original.contentLength();
+		}
+
+		@Override
+		public long lastModified() throws IOException {
+			return this.original.lastModified();
+		}
+
+		@Override
+		public Resource createRelative(String relativePath) throws IOException {
+			return this.original.createRelative(relativePath);
+		}
+
+		@Override
+		public String getDescription() {
+			return original.getDescription();
+		}
+
+		@Override
+		public InputStream getInputStream() throws IOException {
+			return original.getInputStream();
+		}
+
+		@Override
+		public String getVersion() {
+			return this.version;
+		}
+	}
+
+}

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

@@ -0,0 +1,39 @@
+/*
+ * 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.
+ * 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.resource;
+
+import org.springframework.core.io.Resource;
+
+/**
+ * An extension of {@link VersionPathStrategy} that adds a method
+ * to determine the actual version of a {@link Resource}.
+ *
+ * @author Rossen Stoyanchev
+ * @author Brian Clozel
+ * @since 5.0
+ * @see VersionResourceResolver
+*/
+public interface VersionStrategy extends VersionPathStrategy {
+
+	/**
+	 * Determine the version for the given resource.
+	 * @param resource the resource to check
+	 * @return the version (never {@code null})
+	 */
+	String getResourceVersion(Resource resource);
+
+}

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

@@ -0,0 +1,34 @@
+/*
+ * 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.
+ * 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.resource;
+
+import org.springframework.core.io.Resource;
+
+/**
+ * Interface for a resource descriptor that describes its version with a
+ * version string that can be derived from its content and/or metadata.
+ *
+ * @author Rossen Stoyanchev
+ * @author Brian Clozel
+ * @since 5.0
+ * @see VersionResourceResolver
+ */
+public interface VersionedResource extends Resource {
+
+	String getVersion();
+
+}

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

@@ -0,0 +1,124 @@
+/*
+ * 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.
+ * 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.resource;
+
+import java.util.List;
+
+import org.webjars.MultipleMatchesException;
+import org.webjars.WebJarAssetLocator;
+
+import org.springframework.core.io.Resource;
+import org.springframework.web.server.ServerWebExchange;
+
+/**
+ * A {@code ResourceResolver} that delegates to the chain to locate a resource and then
+ * attempts to find a matching versioned resource contained in a WebJar JAR file.
+ *
+ * <p>This allows WebJars.org users to write version agnostic paths in their templates,
+ * like {@code <script src="/jquery/jquery.min.js"/>}.
+ * This path will be resolved to the unique version {@code <script src="/jquery/1.2.0/jquery.min.js"/>},
+ * which is a better fit for HTTP caching and version management in applications.
+ *
+ * <p>This also resolves resources for version agnostic HTTP requests {@code "GET /jquery/jquery.min.js"}.
+ *
+ * <p>This resolver requires the "org.webjars:webjars-locator" library on classpath,
+ * and is automatically registered if that library is present.
+ *
+ * @author Rossen Stoyanchev
+ * @author Brian Clozel
+ * @since 5.0
+ * @see <a href="http://www.webjars.org">webjars.org</a>
+ */
+public class WebJarsResourceResolver extends AbstractResourceResolver {
+
+	private final static String WEBJARS_LOCATION = "META-INF/resources/webjars/";
+
+	private final static int WEBJARS_LOCATION_LENGTH = WEBJARS_LOCATION.length();
+
+
+	private final WebJarAssetLocator webJarAssetLocator;
+
+
+	/**
+	 * Create a {@code WebJarsResourceResolver} with a default {@code WebJarAssetLocator} instance.
+	 */
+	public WebJarsResourceResolver() {
+		this(new WebJarAssetLocator());
+	}
+
+	/**
+	 * Create a {@code WebJarsResourceResolver} with a custom {@code WebJarAssetLocator} instance,
+	 * e.g. with a custom index.
+	 */
+	public WebJarsResourceResolver(WebJarAssetLocator webJarAssetLocator) {
+		this.webJarAssetLocator = webJarAssetLocator;
+	}
+
+
+	@Override
+	protected Resource resolveResourceInternal(ServerWebExchange exchange, String requestPath,
+			List<? extends Resource> locations, ResourceResolverChain chain) {
+
+		Resource resolved = chain.resolveResource(exchange, requestPath, locations);
+		if (resolved == null) {
+			String webJarResourcePath = findWebJarResourcePath(requestPath);
+			if (webJarResourcePath != null) {
+				return chain.resolveResource(exchange, webJarResourcePath, locations);
+			}
+		}
+		return resolved;
+	}
+
+	@Override
+	protected String resolveUrlPathInternal(String resourceUrlPath,
+			List<? extends Resource> locations, ResourceResolverChain chain) {
+
+		String path = chain.resolveUrlPath(resourceUrlPath, locations);
+		if (path == null) {
+			String webJarResourcePath = findWebJarResourcePath(resourceUrlPath);
+			if (webJarResourcePath != null) {
+				return chain.resolveUrlPath(webJarResourcePath, locations);
+			}
+		}
+		return path;
+	}
+
+	protected String findWebJarResourcePath(String path) {
+		try {
+			int startOffset = (path.startsWith("/") ? 1 : 0);
+			int endOffset = path.indexOf("/", 1);
+			if (endOffset != -1) {
+				String webjar = path.substring(startOffset, endOffset);
+				String partialPath = path.substring(endOffset);
+				String webJarPath = webJarAssetLocator.getFullPath(webjar, partialPath);
+				return webJarPath.substring(WEBJARS_LOCATION_LENGTH);
+			}
+		}
+		catch (MultipleMatchesException ex) {
+			if (logger.isWarnEnabled()) {
+				logger.warn("WebJar version conflict for \"" + path + "\"", ex);
+			}
+		}
+		catch (IllegalArgumentException ex) {
+			if (logger.isTraceEnabled()) {
+				logger.trace("No WebJar resource found for \"" + path + "\"");
+			}
+		}
+		return null;
+	}
+
+}

spring-web-reactive/src/main/java/org/springframework/web/reactive/resource/package-info.java

@@ -0,0 +1,4 @@
+/**
+ * Support classes for serving static resources.
+ */
+package org.springframework.web.reactive.resource;

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

@@ -0,0 +1,129 @@
+/*
+ * 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.
+ * 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.resource;
+
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Collections;
+import java.util.List;
+
+import org.hamcrest.Matchers;
+import org.junit.Before;
+import org.junit.Test;
+
+import org.springframework.core.io.ClassPathResource;
+import org.springframework.core.io.Resource;
+import org.springframework.http.HttpMethod;
+import org.springframework.http.server.reactive.ServerHttpResponse;
+import org.springframework.mock.http.server.reactive.test.MockServerHttpRequest;
+import org.springframework.mock.http.server.reactive.test.MockServerHttpResponse;
+import org.springframework.util.FileCopyUtils;
+import org.springframework.web.server.ServerWebExchange;
+import org.springframework.web.server.adapter.DefaultServerWebExchange;
+import org.springframework.web.server.session.DefaultWebSessionManager;
+import org.springframework.web.server.session.WebSessionManager;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertThat;
+import static org.mockito.BDDMockito.given;
+import static org.mockito.BDDMockito.mock;
+
+/**
+ * Unit tests for
+ * {@link AppCacheManifestTransformer}.
+ *
+ * @author Rossen Stoyanchev
+ * @author Brian Clozel
+ */
+public class AppCacheManifestTransformerTests {
+
+	private AppCacheManifestTransformer transformer;
+
+	private ResourceTransformerChain chain;
+
+	private ServerWebExchange exchange;
+
+
+	@Before
+	public void setup() {
+		this.transformer = new AppCacheManifestTransformer();
+		this.chain = mock(ResourceTransformerChain.class);
+
+		MockServerHttpRequest request = new MockServerHttpRequest(HttpMethod.GET, "");
+		ServerHttpResponse response = new MockServerHttpResponse();
+		WebSessionManager manager = new DefaultWebSessionManager();
+		this.exchange = new DefaultServerWebExchange(request, response, manager);
+	}
+
+
+	@Test
+	public void noTransformIfExtensionNoMatch() throws Exception {
+		Resource resource = mock(Resource.class);
+		given(resource.getFilename()).willReturn("foobar.file");
+		given(this.chain.transform(this.exchange, resource)).willReturn(resource);
+
+		Resource result = this.transformer.transform(this.exchange, resource, this.chain);
+		assertEquals(resource, result);
+	}
+
+	@Test
+	public void syntaxErrorInManifest() throws Exception {
+		Resource resource = new ClassPathResource("test/error.manifest", getClass());
+		given(this.chain.transform(this.exchange, resource)).willReturn(resource);
+
+		Resource result = this.transformer.transform(this.exchange, resource, this.chain);
+		assertEquals(resource, result);
+	}
+
+	@Test
+	public void transformManifest() throws Exception {
+
+		VersionResourceResolver versionResolver = new VersionResourceResolver();
+		versionResolver.setStrategyMap(Collections.singletonMap("/**", new ContentVersionStrategy()));
+
+		PathResourceResolver pathResolver = new PathResourceResolver();
+		pathResolver.setAllowedLocations(new ClassPathResource("test/", getClass()));
+
+		List<ResourceResolver> resolvers = Arrays.asList(versionResolver, pathResolver);
+		ResourceResolverChain resolverChain = new DefaultResourceResolverChain(resolvers);
+
+		List<ResourceTransformer> transformers = new ArrayList<>();
+		transformers.add(new CssLinkResourceTransformer());
+		this.chain = new DefaultResourceTransformerChain(resolverChain, transformers);
+
+		Resource resource = new ClassPathResource("test/appcache.manifest", getClass());
+		Resource result = this.transformer.transform(this.exchange, resource, this.chain);
+		byte[] bytes = FileCopyUtils.copyToByteArray(result.getInputStream());
+		String content = new String(bytes, "UTF-8");
+
+		assertThat("should rewrite resource links", content,
+				Matchers.containsString("foo-e36d2e05253c6c7085a91522ce43a0b4.css"));
+		assertThat("should rewrite resource links", content,
+				Matchers.containsString("bar-11e16cf79faee7ac698c805cf28248d2.css"));
+		assertThat("should rewrite resource links", content,
+				Matchers.containsString("js/bar-bd508c62235b832d960298ca6c0b7645.js"));
+
+		assertThat("should not rewrite external resources", content,
+				Matchers.containsString("//example.org/style.css"));
+		assertThat("should not rewrite external resources", content,
+				Matchers.containsString("http://example.org/image.png"));
+
+		assertThat("should generate fingerprint", content,
+				Matchers.containsString("# Hash: 4bf0338bcbeb0a5b3a4ec9ed8864107d"));
+	}
+
+}

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

@@ -0,0 +1,165 @@
+/*
+ * 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.
+ * 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.resource;
+
+import java.util.ArrayList;
+import java.util.List;
+
+import org.junit.Before;
+import org.junit.Test;
+import org.mockito.Mockito;
+
+import org.springframework.cache.Cache;
+import org.springframework.cache.concurrent.ConcurrentMapCache;
+import org.springframework.core.io.ClassPathResource;
+import org.springframework.core.io.Resource;
+import org.springframework.http.HttpMethod;
+import org.springframework.http.server.reactive.ServerHttpResponse;
+import org.springframework.mock.http.server.reactive.test.MockServerHttpRequest;
+import org.springframework.mock.http.server.reactive.test.MockServerHttpResponse;
+import org.springframework.web.server.ServerWebExchange;
+import org.springframework.web.server.adapter.DefaultServerWebExchange;
+import org.springframework.web.server.session.DefaultWebSessionManager;
+import org.springframework.web.server.session.WebSessionManager;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertNull;
+import static org.junit.Assert.assertSame;
+
+/**
+ * Unit tests for {@link CachingResourceResolver}.
+ * @author Rossen Stoyanchev
+ */
+public class CachingResourceResolverTests {
+
+	private Cache cache;
+
+	private ResourceResolverChain chain;
+
+	private List<Resource> locations;
+
+	private ServerWebExchange exchange;
+
+	private MockServerHttpRequest request;
+
+
+	@Before
+	public void setup() {
+
+		this.cache = new ConcurrentMapCache("resourceCache");
+
+		List<ResourceResolver> resolvers = new ArrayList<>();
+		resolvers.add(new CachingResourceResolver(this.cache));
+		resolvers.add(new PathResourceResolver());
+		this.chain = new DefaultResourceResolverChain(resolvers);
+
+		this.locations = new ArrayList<>();
+		this.locations.add(new ClassPathResource("test/", getClass()));
+
+		this.request = new MockServerHttpRequest(HttpMethod.GET, "");
+		ServerHttpResponse response = new MockServerHttpResponse();
+		WebSessionManager manager = new DefaultWebSessionManager();
+		this.exchange = new DefaultServerWebExchange(request, response, manager);
+	}
+
+
+	@Test
+	public void resolveResourceInternal() {
+		String file = "bar.css";
+		Resource expected = new ClassPathResource("test/" + file, getClass());
+		Resource actual = this.chain.resolveResource(this.exchange, file, this.locations);
+
+		assertEquals(expected, actual);
+	}
+
+	@Test
+	public void resolveResourceInternalFromCache() {
+
+		Resource expected = Mockito.mock(Resource.class);
+		this.cache.put(CachingResourceResolver.RESOLVED_RESOURCE_CACHE_KEY_PREFIX + "bar.css", expected);
+
+		String file = "bar.css";
+		Resource actual = this.chain.resolveResource(this.exchange, file, this.locations);
+
+		assertSame(expected, actual);
+	}
+
+	@Test
+	public void resolveResourceInternalNoMatch() {
+		assertNull(this.chain.resolveResource(this.exchange, "invalid.css", this.locations));
+	}
+
+	@Test
+	public void resolverUrlPath() {
+		String expected = "/foo.css";
+		String actual = this.chain.resolveUrlPath(expected, this.locations);
+
+		assertEquals(expected, actual);
+	}
+
+	@Test
+	public void resolverUrlPathFromCache() {
+		String expected = "cached-imaginary.css";
+		this.cache.put(CachingResourceResolver.RESOLVED_URL_PATH_CACHE_KEY_PREFIX + "imaginary.css", expected);
+		String actual = this.chain.resolveUrlPath("imaginary.css", this.locations);
+
+		assertEquals(expected, actual);
+	}
+
+	@Test
+	public void resolverUrlPathNoMatch() {
+		assertNull(this.chain.resolveUrlPath("invalid.css", this.locations));
+	}
+
+	@Test
+	public void resolveResourceAcceptEncodingInCacheKey() {
+		String file = "bar.css";
+		this.request.setUri(file).setHeader("Accept-Encoding", "gzip");
+
+		Resource expected = this.chain.resolveResource(this.exchange, file, this.locations);
+		String cacheKey = CachingResourceResolver.RESOLVED_RESOURCE_CACHE_KEY_PREFIX + file + "+encoding=gzip";
+
+		assertEquals(expected, this.cache.get(cacheKey).get());
+	}
+
+	@Test
+	public void resolveResourceNoAcceptEncodingInCacheKey() {
+		String file = "bar.css";
+		this.request.setUri(file);
+
+		Resource expected = this.chain.resolveResource(this.exchange, file, this.locations);
+		String cacheKey = CachingResourceResolver.RESOLVED_RESOURCE_CACHE_KEY_PREFIX + file;
+
+		assertEquals(expected, this.cache.get(cacheKey).get());
+	}
+
+	@Test
+	public void resolveResourceMatchingEncoding() {
+		Resource resource = Mockito.mock(Resource.class);
+		Resource gzResource = Mockito.mock(Resource.class);
+		this.cache.put(CachingResourceResolver.RESOLVED_RESOURCE_CACHE_KEY_PREFIX + "bar.css", resource);
+		this.cache.put(CachingResourceResolver.RESOLVED_RESOURCE_CACHE_KEY_PREFIX + "bar.css+encoding=gzip", gzResource);
+
+		String file = "bar.css";
+		this.request.setUri(file);
+		assertSame(resource, this.chain.resolveResource(this.exchange, file, this.locations));
+
+		request.addHeader("Accept-Encoding", "gzip");
+		assertSame(gzResource, this.chain.resolveResource(this.exchange, file, this.locations));
+	}
+
+}

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

@@ -0,0 +1,79 @@
+/*
+ * 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.
+ * 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.resource;
+
+import java.util.Collections;
+
+import org.junit.Before;
+import org.junit.Test;
+
+import org.springframework.core.io.ClassPathResource;
+import org.springframework.core.io.Resource;
+import org.springframework.util.DigestUtils;
+import org.springframework.util.FileCopyUtils;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertNull;
+
+/**
+ * Unit tests for {@link ContentVersionStrategy}.
+ * @author Rossen Stoyanchev
+ * @author Brian Clozel
+ */
+public class ContentBasedVersionStrategyTests {
+
+	private ContentVersionStrategy strategy = new ContentVersionStrategy();
+
+
+	@Before
+	public void setup() {
+		VersionResourceResolver versionResourceResolver = new VersionResourceResolver();
+		versionResourceResolver.setStrategyMap(Collections.singletonMap("/**", this.strategy));
+	}
+
+	@Test
+	public void extractVersion() throws Exception {
+		String hash = "7fbe76cdac6093784895bb4989203e5a";
+		String path = "font-awesome/css/font-awesome.min-" + hash + ".css";
+
+		assertEquals(hash, this.strategy.extractVersion(path));
+		assertNull(this.strategy.extractVersion("foo/bar.css"));
+	}
+
+	@Test
+	public void removeVersion() throws Exception {
+		String file = "font-awesome/css/font-awesome.min%s%s.css";
+		String hash = "7fbe76cdac6093784895bb4989203e5a";
+
+		assertEquals(String.format(file, "", ""),  this.strategy.removeVersion(String.format(file, "-", hash), hash));
+		assertNull(this.strategy.extractVersion("foo/bar.css"));
+	}
+
+	@Test
+	public void getResourceVersion() throws Exception {
+		Resource expected = new ClassPathResource("test/bar.css", getClass());
+		String hash = DigestUtils.md5DigestAsHex(FileCopyUtils.copyToByteArray(expected.getInputStream()));
+		assertEquals(hash, this.strategy.getResourceVersion(expected));
+	}
+
+	@Test
+	public void addVersionToUrl() throws Exception {
+		String requestPath = "test/bar.css";
+		String version = "123";
+		assertEquals("test/bar-123.css", this.strategy.addVersion(requestPath, version));
+	}
+
+}

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

@@ -0,0 +1,131 @@
+/*
+ * 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.
+ * 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.resource;
+
+import java.util.Arrays;
+import java.util.Collections;
+import java.util.List;
+
+import org.junit.Before;
+import org.junit.Test;
+import org.mockito.Mockito;
+
+import org.springframework.core.io.ClassPathResource;
+import org.springframework.core.io.Resource;
+import org.springframework.http.HttpMethod;
+import org.springframework.http.server.reactive.ServerHttpResponse;
+import org.springframework.mock.http.server.reactive.test.MockServerHttpRequest;
+import org.springframework.mock.http.server.reactive.test.MockServerHttpResponse;
+import org.springframework.util.StringUtils;
+import org.springframework.web.server.ServerWebExchange;
+import org.springframework.web.server.adapter.DefaultServerWebExchange;
+import org.springframework.web.server.session.DefaultWebSessionManager;
+import org.springframework.web.server.session.WebSessionManager;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertSame;
+
+/**
+ * Unit tests for {@link CssLinkResourceTransformer}.
+ * @author Rossen Stoyanchev
+ */
+public class CssLinkResourceTransformerTests {
+
+	private ResourceTransformerChain transformerChain;
+
+	private ServerWebExchange exchange;
+
+
+	@Before
+	public void setUp() {
+		VersionResourceResolver versionResolver = new VersionResourceResolver();
+		versionResolver.setStrategyMap(Collections.singletonMap("/**", new ContentVersionStrategy()));
+
+		PathResourceResolver pathResolver = new PathResourceResolver();
+		pathResolver.setAllowedLocations(new ClassPathResource("test/", getClass()));
+
+		List<ResourceResolver> resolvers = Arrays.asList(versionResolver, pathResolver);
+		List<ResourceTransformer> transformers = Collections.singletonList(new CssLinkResourceTransformer());
+
+		ResourceResolverChain resolverChain = new DefaultResourceResolverChain(resolvers);
+		this.transformerChain = new DefaultResourceTransformerChain(resolverChain, transformers);
+
+		MockServerHttpRequest request = new MockServerHttpRequest(HttpMethod.GET, "");
+		ServerHttpResponse response = new MockServerHttpResponse();
+		WebSessionManager manager = new DefaultWebSessionManager();
+		this.exchange = new DefaultServerWebExchange(request, response, manager);
+	}
+
+
+	@Test
+	public void transform() throws Exception {
+		Resource css = new ClassPathResource("test/main.css", getClass());
+		TransformedResource actual = (TransformedResource) this.transformerChain.transform(this.exchange, css);
+
+		String expected = "\n" +
+				"@import url(\"bar-11e16cf79faee7ac698c805cf28248d2.css\");\n" +
+				"@import url('bar-11e16cf79faee7ac698c805cf28248d2.css');\n" +
+				"@import url(bar-11e16cf79faee7ac698c805cf28248d2.css);\n\n" +
+				"@import \"foo-e36d2e05253c6c7085a91522ce43a0b4.css\";\n" +
+				"@import 'foo-e36d2e05253c6c7085a91522ce43a0b4.css';\n\n" +
+				"body { background: url(\"images/image-f448cd1d5dba82b774f3202c878230b3.png\") }\n";
+
+		String result = new String(actual.getByteArray(), "UTF-8");
+		result = StringUtils.deleteAny(result, "\r");
+		assertEquals(expected, result);
+	}
+
+	@Test
+	public void transformNoLinks() throws Exception {
+		Resource expected = new ClassPathResource("test/foo.css", getClass());
+		Resource actual = this.transformerChain.transform(this.exchange, expected);
+		assertSame(expected, actual);
+	}
+
+	@Test
+	public void transformExtLinksNotAllowed() throws Exception {
+		ResourceResolverChain resolverChain = Mockito.mock(DefaultResourceResolverChain.class);
+		ResourceTransformerChain transformerChain = new DefaultResourceTransformerChain(resolverChain,
+				Collections.singletonList(new CssLinkResourceTransformer()));
+
+		Resource externalCss = new ClassPathResource("test/external.css", getClass());
+		Resource resource = transformerChain.transform(this.exchange, externalCss);
+		TransformedResource transformedResource = (TransformedResource) resource;
+
+		String expected = "@import url(\"http://example.org/fonts/css\");\n" +
+				"body { background: url(\"file:///home/spring/image.png\") }\n" +
+				"figure { background: url(\"//example.org/style.css\")}";
+		String result = new String(transformedResource.getByteArray(), "UTF-8");
+		result = StringUtils.deleteAny(result, "\r");
+		assertEquals(expected, result);
+
+		Mockito.verify(resolverChain, Mockito.never())
+				.resolveUrlPath("http://example.org/fonts/css", Collections.singletonList(externalCss));
+		Mockito.verify(resolverChain, Mockito.never())
+				.resolveUrlPath("file:///home/spring/image.png", Collections.singletonList(externalCss));
+		Mockito.verify(resolverChain, Mockito.never())
+				.resolveUrlPath("//example.org/style.css", Collections.singletonList(externalCss));
+	}
+
+	@Test
+	public void transformWithNonCssResource() throws Exception {
+		Resource expected = new ClassPathResource("test/images/image.png", getClass());
+		Resource actual = this.transformerChain.transform(this.exchange, expected);
+		assertSame(expected, actual);
+	}
+
+}

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

@@ -0,0 +1,72 @@
+/*
+ * 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.
+ * 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.resource;
+
+import org.junit.Before;
+import org.junit.Test;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertNull;
+
+/**
+ * Unit tests for {@link FixedVersionStrategy}.
+ * @author Rossen Stoyanchev
+ * @author Brian Clozel
+ */
+public class FixedVersionStrategyTests {
+
+	private final String version = "1df341f";
+
+	private final String path = "js/foo.js";
+
+	private FixedVersionStrategy strategy;
+
+
+	@Before
+	public void setup() {
+		this.strategy = new FixedVersionStrategy(this.version);
+	}
+
+
+	@Test(expected = IllegalArgumentException.class)
+	public void emptyPrefixVersion() throws Exception {
+		new FixedVersionStrategy("  ");
+	}
+
+	@Test
+	public void extractVersion() throws Exception {
+		assertEquals(this.version, this.strategy.extractVersion(this.version + "/" + this.path));
+		assertNull(this.strategy.extractVersion(this.path));
+	}
+
+	@Test
+	public void removeVersion() throws Exception {
+		assertEquals("/" + this.path, this.strategy.removeVersion(this.version + "/" + this.path, this.version));
+	}
+
+	@Test
+	public void addVersion() throws Exception {
+		assertEquals(this.version + "/" + this.path, this.strategy.addVersion("/" + this.path, this.version));
+	}
+
+	@Test  // SPR-13727
+	public void addVersionRelativePath() throws Exception {
+		String relativePath = "../" + this.path;
+		assertEquals(relativePath, this.strategy.addVersion(relativePath, this.version));
+	}
+
+}

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

@@ -0,0 +1,182 @@
+/*
+ * 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.
+ * 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.resource;
+
+import java.io.FileOutputStream;
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.zip.GZIPOutputStream;
+
+import org.junit.Before;
+import org.junit.BeforeClass;
+import org.junit.Test;
+
+import org.springframework.cache.Cache;
+import org.springframework.cache.concurrent.ConcurrentMapCache;
+import org.springframework.core.io.ClassPathResource;
+import org.springframework.core.io.FileSystemResource;
+import org.springframework.core.io.Resource;
+import org.springframework.http.HttpMethod;
+import org.springframework.http.server.reactive.ServerHttpResponse;
+import org.springframework.mock.http.server.reactive.test.MockServerHttpRequest;
+import org.springframework.mock.http.server.reactive.test.MockServerHttpResponse;
+import org.springframework.util.FileCopyUtils;
+import org.springframework.web.server.ServerWebExchange;
+import org.springframework.web.server.adapter.DefaultServerWebExchange;
+import org.springframework.web.server.session.DefaultWebSessionManager;
+import org.springframework.web.server.session.WebSessionManager;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertTrue;
+
+
+/**
+ * Unit tests for {@link GzipResourceResolver}.
+ * @author Rossen Stoyanchev
+ */
+public class GzipResourceResolverTests {
+
+	private ResourceResolverChain resolver;
+
+	private List<Resource> locations;
+
+	private Cache cache;
+
+	private ServerWebExchange exchange;
+
+	private MockServerHttpRequest request;
+
+
+	@BeforeClass
+	public static void createGzippedResources() throws IOException {
+		createGzFile("/js/foo.js");
+		createGzFile("foo-e36d2e05253c6c7085a91522ce43a0b4.css");
+	}
+
+	private static void createGzFile(String filePath) throws IOException {
+		Resource location = new ClassPathResource("test/", GzipResourceResolverTests.class);
+		Resource fileResource = new FileSystemResource(location.createRelative(filePath).getFile());
+		Resource gzFileResource = location.createRelative(filePath + ".gz");
+
+		if (gzFileResource.getFile().createNewFile()) {
+			GZIPOutputStream out = new GZIPOutputStream(new FileOutputStream(gzFileResource.getFile()));
+			FileCopyUtils.copy(fileResource.getInputStream(), out);
+		}
+
+		assertTrue(gzFileResource.exists());
+	}
+
+	@Before
+	public void setUp() {
+		this.cache = new ConcurrentMapCache("resourceCache");
+
+		Map<String, VersionStrategy> versionStrategyMap = new HashMap<>();
+		versionStrategyMap.put("/**", new ContentVersionStrategy());
+		VersionResourceResolver versionResolver = new VersionResourceResolver();
+		versionResolver.setStrategyMap(versionStrategyMap);
+
+		List<ResourceResolver> resolvers = new ArrayList<>();
+		resolvers.add(new CachingResourceResolver(this.cache));
+		resolvers.add(new GzipResourceResolver());
+		resolvers.add(versionResolver);
+		resolvers.add(new PathResourceResolver());
+		this.resolver = new DefaultResourceResolverChain(resolvers);
+
+		this.locations = new ArrayList<>();
+		this.locations.add(new ClassPathResource("test/", getClass()));
+		this.locations.add(new ClassPathResource("testalternatepath/", getClass()));
+
+		this.request = new MockServerHttpRequest(HttpMethod.GET, "");
+		ServerHttpResponse response = new MockServerHttpResponse();
+		WebSessionManager manager = new DefaultWebSessionManager();
+		this.exchange = new DefaultServerWebExchange(request, response, manager);
+	}
+
+
+	@Test
+	public void resolveGzippedFile() throws IOException {
+		this.request.addHeader("Accept-Encoding", "gzip");
+		String file = "js/foo.js";
+		Resource resolved = this.resolver.resolveResource(this.exchange, file, this.locations);
+
+		String gzFile = file+".gz";
+		Resource resource = new ClassPathResource("test/" + gzFile, getClass());
+		assertEquals(resource.getDescription(), resolved.getDescription());
+		assertEquals(new ClassPathResource("test/" + file).getFilename(), resolved.getFilename());
+		assertTrue("Expected " + resolved + " to be of type " + EncodedResource.class,
+				resolved instanceof EncodedResource);
+	}
+
+	@Test
+	public void resolveFingerprintedGzippedFile() throws IOException {
+		this.request.addHeader("Accept-Encoding", "gzip");
+		String file = "foo-e36d2e05253c6c7085a91522ce43a0b4.css";
+		Resource resolved = this.resolver.resolveResource(this.exchange, file, this.locations);
+
+		String gzFile = file + ".gz";
+		Resource resource = new ClassPathResource("test/" + gzFile, getClass());
+		assertEquals(resource.getDescription(), resolved.getDescription());
+		assertEquals(new ClassPathResource("test/"+file).getFilename(), resolved.getFilename());
+		assertTrue("Expected " + resolved + " to be of type " + EncodedResource.class,
+				resolved instanceof EncodedResource);
+	}
+
+	@Test
+	public void resolveFromCacheWithEncodingVariants() throws IOException {
+		this.request.addHeader("Accept-Encoding", "gzip");
+		String file = "js/foo.js";
+		Resource resolved = this.resolver.resolveResource(this.exchange, file, this.locations);
+
+		String gzFile = file+".gz";
+		Resource gzResource = new ClassPathResource("test/"+gzFile, getClass());
+		assertEquals(gzResource.getDescription(), resolved.getDescription());
+		assertEquals(new ClassPathResource("test/" + file).getFilename(), resolved.getFilename());
+		assertTrue("Expected " + resolved + " to be of type " + EncodedResource.class,
+				resolved instanceof EncodedResource);
+
+		// resolved resource is now cached in CachingResourceResolver
+
+		this.request = new MockServerHttpRequest(HttpMethod.GET, "/js/foo.js");
+		MockServerHttpResponse response = new MockServerHttpResponse();
+		this.exchange = new DefaultServerWebExchange(this.request, response, new DefaultWebSessionManager());
+
+		resolved = this.resolver.resolveResource(this.exchange, file, this.locations);
+
+		Resource resource = new ClassPathResource("test/"+file, getClass());
+		assertEquals(resource.getDescription(), resolved.getDescription());
+		assertEquals(new ClassPathResource("test/" + file).getFilename(), resolved.getFilename());
+		assertFalse("Expected " + resolved + " to *not* be of type " + EncodedResource.class,
+				resolved instanceof EncodedResource);
+	}
+
+	@Test // SPR-13149
+	public void resolveWithNullRequest() throws IOException {
+		String file = "js/foo.js";
+		Resource resolved = this.resolver.resolveResource(null, file, this.locations);
+
+		String gzFile = file+".gz";
+		Resource gzResource = new ClassPathResource("test/" + gzFile, getClass());
+		assertEquals(gzResource.getDescription(), resolved.getDescription());
+		assertEquals(new ClassPathResource("test/" + file).getFilename(), resolved.getFilename());
+		assertTrue("Expected " + resolved + " to be of type " + EncodedResource.class,
+				resolved instanceof EncodedResource);
+	}
+}

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

@@ -0,0 +1,116 @@
+/*
+ * 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.
+ * 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.resource;
+
+import java.io.IOException;
+
+import org.junit.Test;
+
+import org.springframework.core.io.ClassPathResource;
+import org.springframework.core.io.Resource;
+import org.springframework.core.io.UrlResource;
+
+import static java.util.Collections.singletonList;
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertNotNull;
+import static org.junit.Assert.assertNull;
+import static org.junit.Assert.assertTrue;
+import static org.junit.Assert.fail;
+
+/**
+ * Unit tests for {@link PathResourceResolver}.
+ * @author Rossen Stoyanchev
+ */
+public class PathResourceResolverTests {
+
+	private final PathResourceResolver resolver = new PathResourceResolver();
+
+
+	@Test
+	public void resolveFromClasspath() throws IOException {
+		Resource location = new ClassPathResource("test/", PathResourceResolver.class);
+		String path = "bar.css";
+		Resource actual = this.resolver.resolveResource(null, path, singletonList(location), null);
+		assertEquals(location.createRelative(path), actual);
+	}
+
+	@Test
+	public void resolveFromClasspathRoot() throws IOException {
+		Resource location = new ClassPathResource("/");
+		String path = "org/springframework/web/reactive/resource/test/bar.css";
+		Resource actual = this.resolver.resolveResource(null, path, singletonList(location), null);
+		assertNotNull(actual);
+	}
+
+	@Test
+	public void checkResource() throws IOException {
+		Resource location = new ClassPathResource("test/", PathResourceResolver.class);
+		testCheckResource(location, "../testsecret/secret.txt");
+		testCheckResource(location, "test/../../testsecret/secret.txt");
+
+		location = new UrlResource(getClass().getResource("./test/"));
+		String secretPath = new UrlResource(getClass().getResource("testsecret/secret.txt")).getURL().getPath();
+		testCheckResource(location, "file:" + secretPath);
+		testCheckResource(location, "/file:" + secretPath);
+		testCheckResource(location, "/" + secretPath);
+		testCheckResource(location, "////../.." + secretPath);
+		testCheckResource(location, "/%2E%2E/testsecret/secret.txt");
+		testCheckResource(location, "/%2e%2e/testsecret/secret.txt");
+		testCheckResource(location, " " + secretPath);
+		testCheckResource(location, "/  " + secretPath);
+		testCheckResource(location, "url:" + secretPath);
+	}
+
+	private void testCheckResource(Resource location, String requestPath) throws IOException {
+		Resource actual = this.resolver.resolveResource(null, requestPath, singletonList(location), null);
+		if (!location.createRelative(requestPath).exists() && !requestPath.contains(":")) {
+			fail(requestPath + " doesn't actually exist as a relative path");
+		}
+		assertNull(actual);
+	}
+
+	@Test
+	public void checkResourceWithAllowedLocations() {
+		this.resolver.setAllowedLocations(
+				new ClassPathResource("test/", PathResourceResolver.class),
+				new ClassPathResource("testalternatepath/", PathResourceResolver.class)
+		);
+
+		Resource location = new ClassPathResource("test/main.css", PathResourceResolver.class);
+		String actual = this.resolver.resolveUrlPath("../testalternatepath/bar.css", singletonList(location), null);
+		assertEquals("../testalternatepath/bar.css", actual);
+	}
+
+	@Test // SPR-12624
+	public void checkRelativeLocation() throws Exception {
+		String locationUrl= new UrlResource(getClass().getResource("./test/")).getURL().toExternalForm();
+		Resource location = new UrlResource(locationUrl.replace("/springframework","/../org/springframework"));
+		assertNotNull(this.resolver.resolveResource(null, "main.css", singletonList(location), null));
+	}
+
+	@Test // SPR-12747
+	public void checkFileLocation() throws Exception {
+		Resource resource = new ClassPathResource("test/main.css", PathResourceResolver.class);
+		assertTrue(this.resolver.checkResource(resource, resource));
+	}
+
+	@Test // SPR-13241
+	public void resolvePathRootResource() throws Exception {
+		Resource webjarsLocation = new ClassPathResource("/META-INF/resources/webjars/", PathResourceResolver.class);
+		String path = this.resolver.resolveUrlPathInternal("", singletonList(webjarsLocation), null);
+		assertNull(path);
+	}
+}

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

@@ -0,0 +1,116 @@
+/*
+ * 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.
+ * 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.resource;
+
+import java.util.Arrays;
+import java.util.Collections;
+import java.util.List;
+
+import org.junit.Before;
+import org.junit.Test;
+
+import org.springframework.core.io.ClassPathResource;
+import org.springframework.core.io.Resource;
+import org.springframework.http.HttpMethod;
+import org.springframework.http.server.reactive.ServerHttpResponse;
+import org.springframework.mock.http.server.reactive.test.MockServerHttpRequest;
+import org.springframework.mock.http.server.reactive.test.MockServerHttpResponse;
+import org.springframework.web.server.ServerWebExchange;
+import org.springframework.web.server.adapter.DefaultServerWebExchange;
+import org.springframework.web.server.session.DefaultWebSessionManager;
+import org.springframework.web.server.session.WebSessionManager;
+
+import static org.junit.Assert.assertEquals;
+
+/**
+ * Unit tests for {@code ResourceTransformerSupport}.
+ *
+ * @author Rossen Stoyanchev
+ * @author Brian Clozel
+ */
+public class ResourceTransformerSupportTests {
+
+	private ResourceTransformerChain transformerChain;
+
+	private TestResourceTransformerSupport transformer;
+
+	private ServerWebExchange exchange;
+
+	private MockServerHttpRequest request;
+
+
+	@Before
+	public void setUp() {
+		VersionResourceResolver versionResolver = new VersionResourceResolver();
+		versionResolver.setStrategyMap(Collections.singletonMap("/**", new ContentVersionStrategy()));
+		PathResourceResolver pathResolver = new PathResourceResolver();
+		pathResolver.setAllowedLocations(new ClassPathResource("test/", getClass()));
+		List<ResourceResolver> resolvers = Arrays.asList(versionResolver, pathResolver);
+		this.transformerChain = new DefaultResourceTransformerChain(new DefaultResourceResolverChain(resolvers), null);
+
+		this.transformer = new TestResourceTransformerSupport();
+		this.transformer.setResourceUrlProvider(createResourceUrlProvider(resolvers));
+
+		this.request = new MockServerHttpRequest(HttpMethod.GET, "");
+		ServerHttpResponse response = new MockServerHttpResponse();
+		WebSessionManager manager = new DefaultWebSessionManager();
+		this.exchange = new DefaultServerWebExchange(this.request, response, manager);
+	}
+
+	private ResourceUrlProvider createResourceUrlProvider(List<ResourceResolver> resolvers) {
+		ResourceWebHandler handler = new ResourceWebHandler();
+		handler.setLocations(Collections.singletonList(new ClassPathResource("test/", getClass())));
+		handler.setResourceResolvers(resolvers);
+		ResourceUrlProvider urlProvider = new ResourceUrlProvider();
+		urlProvider.setHandlerMap(Collections.singletonMap("/resources/**", handler));
+		return urlProvider;
+	}
+
+
+	@Test
+	public void resolveUrlPath() throws Exception {
+		this.request.setUri("/resources/main.css");
+		String resourcePath = "/resources/bar.css";
+		Resource css = new ClassPathResource("test/main.css", getClass());
+		String actual = this.transformer.resolveUrlPath(resourcePath, this.exchange, css, this.transformerChain);
+		assertEquals("/resources/bar-11e16cf79faee7ac698c805cf28248d2.css", actual);
+		assertEquals("/resources/bar-11e16cf79faee7ac698c805cf28248d2.css", actual);
+	}
+
+	@Test
+	public void resolveUrlPathWithRelativePath() throws Exception {
+		Resource css = new ClassPathResource("test/main.css", getClass());
+		String actual = this.transformer.resolveUrlPath("bar.css", this.exchange, css, this.transformerChain);
+		assertEquals("bar-11e16cf79faee7ac698c805cf28248d2.css", actual);
+	}
+
+	@Test
+	public void resolveUrlPathWithRelativePathInParentDirectory() throws Exception {
+		Resource imagePng = new ClassPathResource("test/images/image.png", getClass());
+		String actual = this.transformer.resolveUrlPath("../bar.css", this.exchange, imagePng, this.transformerChain);
+		assertEquals("../bar-11e16cf79faee7ac698c805cf28248d2.css", actual);
+	}
+
+
+	private static class TestResourceTransformerSupport extends ResourceTransformerSupport {
+
+		@Override
+		public Resource transform(ServerWebExchange exchange, Resource resource, ResourceTransformerChain chain) {
+			throw new IllegalStateException("Should never be called");
+		}
+	}
+
+}

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

@@ -0,0 +1,163 @@
+/*
+ * 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.
+ * 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.resource;
+
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+
+import org.hamcrest.Matchers;
+import org.junit.Before;
+import org.junit.Test;
+
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Configuration;
+import org.springframework.core.io.ClassPathResource;
+import org.springframework.core.io.Resource;
+import org.springframework.http.HttpMethod;
+import org.springframework.mock.http.server.reactive.test.MockServerHttpRequest;
+import org.springframework.mock.http.server.reactive.test.MockServerHttpResponse;
+import org.springframework.mock.web.test.MockServletContext;
+import org.springframework.web.context.support.AnnotationConfigWebApplicationContext;
+import org.springframework.web.reactive.handler.SimpleUrlHandlerMapping;
+import org.springframework.web.server.ServerWebExchange;
+import org.springframework.web.server.adapter.DefaultServerWebExchange;
+import org.springframework.web.server.session.DefaultWebSessionManager;
+import org.springframework.web.server.session.WebSessionManager;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertThat;
+
+
+/**
+ * Unit tests for {@link ResourceUrlProvider}.
+ *
+ * @author Rossen Stoyanchev
+ */
+public class ResourceUrlProviderTests {
+
+	private final List<Resource> locations = new ArrayList<>();
+
+	private final ResourceWebHandler handler = new ResourceWebHandler();
+
+	private final Map<String, ResourceWebHandler> handlerMap = new HashMap<>();
+
+	private final ResourceUrlProvider urlProvider = new ResourceUrlProvider();
+
+
+	@Before
+	public void setUp() throws Exception {
+		this.locations.add(new ClassPathResource("test/", getClass()));
+		this.locations.add(new ClassPathResource("testalternatepath/", getClass()));
+		this.handler.setLocations(locations);
+		this.handler.afterPropertiesSet();
+		this.handlerMap.put("/resources/**", this.handler);
+		this.urlProvider.setHandlerMap(this.handlerMap);
+	}
+
+
+	@Test
+	public void getStaticResourceUrl() {
+		String url = this.urlProvider.getForLookupPath("/resources/foo.css");
+		assertEquals("/resources/foo.css", url);
+	}
+
+	@Test // SPR-13374
+	public void getStaticResourceUrlRequestWithRequestParams() {
+		MockServerHttpRequest request = new MockServerHttpRequest(HttpMethod.GET, "/");
+		MockServerHttpResponse response = new MockServerHttpResponse();
+		WebSessionManager manager = new DefaultWebSessionManager();
+		ServerWebExchange exchange = new DefaultServerWebExchange(request, response, manager);
+
+		String url = "/resources/foo.css?foo=bar&url=http://example.org";
+		String resolvedUrl = this.urlProvider.getForRequestUrl(exchange, url);
+		assertEquals(url, resolvedUrl);
+	}
+
+	@Test
+	public void getFingerprintedResourceUrl() {
+		Map<String, VersionStrategy> versionStrategyMap = new HashMap<>();
+		versionStrategyMap.put("/**", new ContentVersionStrategy());
+		VersionResourceResolver versionResolver = new VersionResourceResolver();
+		versionResolver.setStrategyMap(versionStrategyMap);
+
+		List<ResourceResolver> resolvers = new ArrayList<>();
+		resolvers.add(versionResolver);
+		resolvers.add(new PathResourceResolver());
+		this.handler.setResourceResolvers(resolvers);
+
+		String url = this.urlProvider.getForLookupPath("/resources/foo.css");
+		assertEquals("/resources/foo-e36d2e05253c6c7085a91522ce43a0b4.css", url);
+	}
+
+	@Test // SPR-12647
+	public void bestPatternMatch() throws Exception {
+		ResourceWebHandler otherHandler = new ResourceWebHandler();
+		otherHandler.setLocations(this.locations);
+		Map<String, VersionStrategy> versionStrategyMap = new HashMap<>();
+		versionStrategyMap.put("/**", new ContentVersionStrategy());
+		VersionResourceResolver versionResolver = new VersionResourceResolver();
+		versionResolver.setStrategyMap(versionStrategyMap);
+
+		List<ResourceResolver> resolvers = new ArrayList<>();
+		resolvers.add(versionResolver);
+		resolvers.add(new PathResourceResolver());
+		otherHandler.setResourceResolvers(resolvers);
+
+		this.handlerMap.put("/resources/*.css", otherHandler);
+		this.urlProvider.setHandlerMap(this.handlerMap);
+
+		String url = this.urlProvider.getForLookupPath("/resources/foo.css");
+		assertEquals("/resources/foo-e36d2e05253c6c7085a91522ce43a0b4.css", url);
+	}
+
+	@Test // SPR-12592
+	public void initializeOnce() throws Exception {
+		AnnotationConfigWebApplicationContext context = new AnnotationConfigWebApplicationContext();
+		context.setServletContext(new MockServletContext());
+		context.register(HandlerMappingConfiguration.class);
+		context.refresh();
+
+		ResourceUrlProvider urlProviderBean = context.getBean(ResourceUrlProvider.class);
+		assertThat(urlProviderBean.getHandlerMap(), Matchers.hasKey("/resources/**"));
+		assertFalse(urlProviderBean.isAutodetect());
+	}
+
+
+	@Configuration
+	@SuppressWarnings({"unused", "WeakerAccess"})
+	static class HandlerMappingConfiguration {
+
+		@Bean
+		public SimpleUrlHandlerMapping simpleUrlHandlerMapping() {
+			ResourceWebHandler handler = new ResourceWebHandler();
+			HashMap<String, ResourceWebHandler> handlerMap = new HashMap<>();
+			handlerMap.put("/resources/**", handler);
+			SimpleUrlHandlerMapping hm = new SimpleUrlHandlerMapping();
+			hm.setUrlMap(handlerMap);
+			return hm;
+		}
+
+		@Bean
+		public ResourceUrlProvider resourceUrlProvider() {
+			return new ResourceUrlProvider();
+		}
+	}
+
+}

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

@@ -0,0 +1,594 @@
+/*
+ * 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.
+ * 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.resource;
+
+import java.io.IOException;
+import java.nio.charset.StandardCharsets;
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Collections;
+import java.util.List;
+import java.util.concurrent.TimeUnit;
+
+import org.junit.Before;
+import org.junit.Ignore;
+import org.junit.Test;
+
+import org.springframework.core.io.ClassPathResource;
+import org.springframework.core.io.Resource;
+import org.springframework.core.io.UrlResource;
+import org.springframework.core.io.buffer.support.DataBufferTestUtils;
+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.mock.http.server.reactive.test.MockServerHttpRequest;
+import org.springframework.mock.http.server.reactive.test.MockServerHttpResponse;
+import org.springframework.tests.TestSubscriber;
+import org.springframework.util.StringUtils;
+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;
+import org.springframework.web.server.adapter.DefaultServerWebExchange;
+import org.springframework.web.server.session.DefaultWebSessionManager;
+import org.springframework.web.server.session.WebSessionManager;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertNull;
+import static org.junit.Assert.assertSame;
+import static org.junit.Assert.assertTrue;
+import static org.junit.Assert.fail;
+import static org.springframework.web.reactive.HandlerMapping.PATH_WITHIN_HANDLER_MAPPING_ATTRIBUTE;
+
+/**
+ * Unit tests for {@link ResourceWebHandler}.
+ * @author Rossen Stoyanchev
+ */
+public class ResourceWebHandlerTests {
+
+	private ResourceWebHandler handler;
+
+	private ServerWebExchange exchange;
+
+	private MockServerHttpRequest request = new MockServerHttpRequest(HttpMethod.GET, "");
+
+	private MockServerHttpResponse response = new MockServerHttpResponse();
+
+	private WebSessionManager sessionManager = new DefaultWebSessionManager();
+
+
+	@Before
+	public void setUp() throws Exception {
+
+		List<Resource> paths = new ArrayList<>(2);
+		paths.add(new ClassPathResource("test/", getClass()));
+		paths.add(new ClassPathResource("testalternatepath/", getClass()));
+		paths.add(new ClassPathResource("META-INF/resources/webjars/"));
+
+		this.handler = new ResourceWebHandler();
+		this.handler.setLocations(paths);
+		this.handler.setCacheControl(CacheControl.maxAge(3600, TimeUnit.SECONDS));
+		this.handler.afterPropertiesSet();
+		this.handler.afterSingletonsInstantiated();
+
+		this.exchange = new DefaultServerWebExchange(this.request, this.response, this.sessionManager);
+	}
+
+	@Test
+	public void getResource() throws Exception {
+		this.exchange.getAttributes().put(PATH_WITHIN_HANDLER_MAPPING_ATTRIBUTE, "foo.css");
+		this.handler.handle(this.exchange).blockMillis(5000);
+
+		HttpHeaders headers = this.response.getHeaders();
+		assertEquals(MediaType.parseMediaType("text/css"), headers.getContentType());
+		assertEquals(17, headers.getContentLength());
+		assertEquals("max-age=3600", headers.getCacheControl());
+		assertTrue(headers.containsKey("Last-Modified"));
+		assertEquals(headers.getLastModified(), resourceLastModifiedDate("test/foo.css"));
+		assertEquals("bytes", headers.getFirst("Accept-Ranges"));
+		assertEquals(1, headers.get("Accept-Ranges").size());
+		assertResponseBody("h1 { color:red; }");
+	}
+
+	@Test
+	public void getResourceHttpHeader() throws Exception {
+		this.request.setHttpMethod(HttpMethod.HEAD);
+		this.exchange.getAttributes().put(PATH_WITHIN_HANDLER_MAPPING_ATTRIBUTE, "foo.css");
+		this.handler.handle(this.exchange).blockMillis(5000);
+
+		assertNull(this.response.getStatusCode());
+		HttpHeaders headers = this.response.getHeaders();
+		assertEquals(MediaType.parseMediaType("text/css"), headers.getContentType());
+		assertEquals(17, headers.getContentLength());
+		assertEquals("max-age=3600", headers.getCacheControl());
+		assertTrue(headers.containsKey("Last-Modified"));
+		assertEquals(headers.getLastModified(), resourceLastModifiedDate("test/foo.css"));
+		assertEquals("bytes", headers.getFirst("Accept-Ranges"));
+		assertEquals(1, headers.get("Accept-Ranges").size());
+		assertNull(this.response.getBody());
+	}
+
+	@Test
+	public void getResourceHttpOptions() throws Exception {
+		this.request.setHttpMethod(HttpMethod.OPTIONS);
+		this.exchange.getAttributes().put(PATH_WITHIN_HANDLER_MAPPING_ATTRIBUTE, "foo.css");
+		this.handler.handle(this.exchange).blockMillis(5000);
+
+		assertNull(this.response.getStatusCode());
+		assertEquals("GET,HEAD,OPTIONS", this.response.getHeaders().getFirst("Allow"));
+	}
+
+	@Test
+	public void getResourceNoCache() throws Exception {
+		this.exchange.getAttributes().put(PATH_WITHIN_HANDLER_MAPPING_ATTRIBUTE, "foo.css");
+		this.handler.setCacheControl(CacheControl.noStore());
+		this.handler.handle(this.exchange).blockMillis(5000);
+
+		assertEquals("no-store", this.response.getHeaders().getCacheControl());
+		assertTrue(this.response.getHeaders().containsKey("Last-Modified"));
+		assertEquals(this.response.getHeaders().getLastModified(), resourceLastModifiedDate("test/foo.css"));
+		assertEquals("bytes", this.response.getHeaders().getFirst("Accept-Ranges"));
+		assertEquals(1, this.response.getHeaders().get("Accept-Ranges").size());
+	}
+
+	@Test
+	public void getVersionedResource() throws Exception {
+		VersionResourceResolver versionResolver = new VersionResourceResolver();
+		versionResolver.addFixedVersionStrategy("versionString", "/**");
+		this.handler.setResourceResolvers(Arrays.asList(versionResolver, new PathResourceResolver()));
+		this.handler.afterPropertiesSet();
+		this.handler.afterSingletonsInstantiated();
+
+		this.exchange.getAttributes().put(PATH_WITHIN_HANDLER_MAPPING_ATTRIBUTE, "versionString/foo.css");
+		this.handler.handle(this.exchange).blockMillis(5000);
+
+		assertEquals("\"versionString\"", this.response.getHeaders().getETag());
+		assertEquals("bytes", this.response.getHeaders().getFirst("Accept-Ranges"));
+		assertEquals(1, this.response.getHeaders().get("Accept-Ranges").size());
+	}
+
+	@Test
+	public void getResourceWithHtmlMediaType() throws Exception {
+		this.exchange.getAttributes().put(PATH_WITHIN_HANDLER_MAPPING_ATTRIBUTE, "foo.html");
+		this.handler.handle(this.exchange).blockMillis(5000);
+
+		HttpHeaders headers = this.response.getHeaders();
+		assertEquals(MediaType.TEXT_HTML, headers.getContentType());
+		assertEquals("max-age=3600", headers.getCacheControl());
+		assertTrue(headers.containsKey("Last-Modified"));
+		assertEquals(headers.getLastModified(), resourceLastModifiedDate("test/foo.html"));
+		assertEquals("bytes", headers.getFirst("Accept-Ranges"));
+		assertEquals(1, headers.get("Accept-Ranges").size());
+	}
+
+	@Test
+	public void getResourceFromAlternatePath() throws Exception {
+		this.exchange.getAttributes().put(PATH_WITHIN_HANDLER_MAPPING_ATTRIBUTE, "baz.css");
+		this.handler.handle(this.exchange).blockMillis(5000);
+
+		HttpHeaders headers = this.response.getHeaders();
+		assertEquals(MediaType.parseMediaType("text/css"), headers.getContentType());
+		assertEquals(17, headers.getContentLength());
+		assertEquals("max-age=3600", headers.getCacheControl());
+		assertTrue(headers.containsKey("Last-Modified"));
+		assertEquals(headers.getLastModified(), resourceLastModifiedDate("testalternatepath/baz.css"));
+		assertEquals("bytes", headers.getFirst("Accept-Ranges"));
+		assertEquals(1, headers.get("Accept-Ranges").size());
+		assertResponseBody("h1 { color:red; }");
+	}
+
+	@Test
+	public void getResourceFromSubDirectory() throws Exception {
+		this.exchange.getAttributes().put(PATH_WITHIN_HANDLER_MAPPING_ATTRIBUTE, "js/foo.js");
+		this.handler.handle(this.exchange).blockMillis(5000);
+
+		assertEquals(MediaType.parseMediaType("text/javascript"), this.response.getHeaders().getContentType());
+		assertResponseBody("function foo() { console.log(\"hello world\"); }");
+	}
+
+	@Test
+	public void getResourceFromSubDirectoryOfAlternatePath() throws Exception {
+		this.exchange.getAttributes().put(PATH_WITHIN_HANDLER_MAPPING_ATTRIBUTE, "js/baz.js");
+		this.handler.handle(this.exchange).blockMillis(5000);
+
+		assertEquals(MediaType.parseMediaType("text/javascript"), this.response.getHeaders().getContentType());
+		assertResponseBody("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();
+
+		this.exchange.getAttributes().put(PATH_WITHIN_HANDLER_MAPPING_ATTRIBUTE, "foo.css");
+		handler.handle(this.exchange).blockMillis(5000);
+
+		assertEquals(MediaType.parseMediaType("foo/bar"), this.response.getHeaders().getContentType());
+		assertResponseBody("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();
+
+		this.request.addHeader("Accept", "application/json,text/plain,*/*");
+		this.exchange.getAttributes().put(PATH_WITHIN_HANDLER_MAPPING_ATTRIBUTE, "foo.html");
+		handler.handle(this.exchange);
+
+		assertEquals(MediaType.TEXT_HTML, this.response.getHeaders().getContentType());
+	}
+
+	@Test
+	public void invalidPath() throws Exception {
+		for (HttpMethod method : HttpMethod.values()) {
+			this.request = new MockServerHttpRequest(HttpMethod.GET, "");
+			this.response = new MockServerHttpResponse();
+			this.sessionManager = new DefaultWebSessionManager();
+			this.exchange = new DefaultServerWebExchange(this.request, this.response, this.sessionManager);
+			testInvalidPath(method);
+		}
+	}
+
+	private void testInvalidPath(HttpMethod httpMethod) throws Exception {
+		this.request.setHttpMethod(httpMethod);
+
+		Resource location = new ClassPathResource("test/", getClass());
+		this.handler.setLocations(Collections.singletonList(location));
+
+		testInvalidPath(location, "../testsecret/secret.txt");
+		testInvalidPath(location, "test/../../testsecret/secret.txt");
+		testInvalidPath(location, ":/../../testsecret/secret.txt");
+
+		location = new UrlResource(getClass().getResource("./test/"));
+		this.handler.setLocations(Collections.singletonList(location));
+		Resource secretResource = new UrlResource(getClass().getResource("testsecret/secret.txt"));
+		String secretPath = secretResource.getURL().getPath();
+
+		testInvalidPath(location, "file:" + secretPath);
+		testInvalidPath(location, "/file:" + secretPath);
+		testInvalidPath(location, "url:" + secretPath);
+		testInvalidPath(location, "/url:" + secretPath);
+		testInvalidPath(location, "/" + secretPath);
+		testInvalidPath(location, "////../.." + secretPath);
+		testInvalidPath(location, "/%2E%2E/testsecret/secret.txt");
+		testInvalidPath(location, "/  " + secretPath);
+		testInvalidPath(location, "url:" + secretPath);
+	}
+
+	private void testInvalidPath(Resource location, String requestPath) throws Exception {
+		this.response = new MockServerHttpResponse();
+		this.exchange = new DefaultServerWebExchange(this.request, this.response, this.sessionManager);
+		this.exchange.getAttributes().put(PATH_WITHIN_HANDLER_MAPPING_ATTRIBUTE, requestPath);
+		this.handler.handle(this.exchange).blockMillis(5000);
+		if (!location.createRelative(requestPath).exists() && !requestPath.contains(":")) {
+			fail(requestPath + " doesn't actually exist as a relative path");
+		}
+		assertEquals(HttpStatus.NOT_FOUND, this.response.getStatusCode());
+	}
+
+	@Test
+	public void ignoreInvalidEscapeSequence() throws Exception {
+		this.response = new MockServerHttpResponse();
+		this.exchange = new DefaultServerWebExchange(this.request, this.response, this.sessionManager);
+		this.exchange.getAttributes().put(PATH_WITHIN_HANDLER_MAPPING_ATTRIBUTE, "/%foo%/bar.txt");
+		this.handler.handle(this.exchange).blockMillis(5000);
+		assertEquals(HttpStatus.NOT_FOUND, this.response.getStatusCode());
+	}
+
+	@Test
+	public void processPath() throws Exception {
+		assertSame("/foo/bar", this.handler.processPath("/foo/bar"));
+		assertSame("foo/bar", this.handler.processPath("foo/bar"));
+
+		// leading whitespace control characters (00-1F)
+		assertEquals("/foo/bar", this.handler.processPath("  /foo/bar"));
+		assertEquals("/foo/bar", this.handler.processPath((char) 1 + "/foo/bar"));
+		assertEquals("/foo/bar", this.handler.processPath((char) 31 + "/foo/bar"));
+		assertEquals("foo/bar", this.handler.processPath("  foo/bar"));
+		assertEquals("foo/bar", this.handler.processPath((char) 31 + "foo/bar"));
+
+		// leading control character 0x7F (DEL)
+		assertEquals("/foo/bar", this.handler.processPath((char) 127 + "/foo/bar"));
+		assertEquals("/foo/bar", this.handler.processPath((char) 127 + "/foo/bar"));
+
+		// leading control and '/' characters
+		assertEquals("/foo/bar", this.handler.processPath("  /  foo/bar"));
+		assertEquals("/foo/bar", this.handler.processPath("  /  /  foo/bar"));
+		assertEquals("/foo/bar", this.handler.processPath("  // /// ////  foo/bar"));
+		assertEquals("/foo/bar", this.handler.processPath((char) 1 + " / " + (char) 127 + " // foo/bar"));
+
+		// root or empty path
+		assertEquals("", this.handler.processPath("   "));
+		assertEquals("/", this.handler.processPath("/"));
+		assertEquals("/", this.handler.processPath("///"));
+		assertEquals("/", this.handler.processPath("/ /   / "));
+	}
+
+	@Test
+	public void initAllowedLocations() throws Exception {
+		PathResourceResolver resolver = (PathResourceResolver) this.handler.getResourceResolvers().get(0);
+		Resource[] locations = resolver.getAllowedLocations();
+
+		assertEquals(3, locations.length);
+		assertEquals("test/", ((ClassPathResource) locations[0]).getPath());
+		assertEquals("testalternatepath/", ((ClassPathResource) locations[1]).getPath());
+		assertEquals("META-INF/resources/webjars/", ((ClassPathResource) locations[2]).getPath());
+	}
+
+	@Test
+	public void initAllowedLocationsWithExplicitConfiguration() throws Exception {
+		ClassPathResource location1 = new ClassPathResource("test/", getClass());
+		ClassPathResource location2 = new ClassPathResource("testalternatepath/", getClass());
+
+		PathResourceResolver pathResolver = new PathResourceResolver();
+		pathResolver.setAllowedLocations(location1);
+
+		ResourceWebHandler handler = new ResourceWebHandler();
+		handler.setResourceResolvers(Collections.singletonList(pathResolver));
+		handler.setLocations(Arrays.asList(location1, location2));
+		handler.afterPropertiesSet();
+		handler.afterSingletonsInstantiated();
+
+		Resource[] locations = pathResolver.getAllowedLocations();
+		assertEquals(1, locations.length);
+		assertEquals("test/", ((ClassPathResource) locations[0]).getPath());
+	}
+
+	@Test
+	public void notModified() throws Exception {
+		this.exchange.getAttributes().put(PATH_WITHIN_HANDLER_MAPPING_ATTRIBUTE, "foo.css");
+		this.request.getHeaders().setIfModifiedSince(resourceLastModified("test/foo.css"));
+		this.handler.handle(this.exchange).blockMillis(5000);
+		assertEquals(HttpStatus.NOT_MODIFIED, this.response.getStatusCode());
+	}
+
+	@Test
+	public void modified() throws Exception {
+		this.exchange.getAttributes().put(PATH_WITHIN_HANDLER_MAPPING_ATTRIBUTE, "foo.css");
+		this.request.getHeaders().setIfModifiedSince(resourceLastModified("test/foo.css") / 1000 * 1000 - 1);
+		this.handler.handle(this.exchange).blockMillis(5000);
+
+		assertNull(this.response.getStatusCode());
+		assertResponseBody("h1 { color:red; }");
+	}
+
+	@Test
+	public void directory() throws Exception {
+		this.exchange.getAttributes().put(PATH_WITHIN_HANDLER_MAPPING_ATTRIBUTE, "js/");
+		this.handler.handle(this.exchange).blockMillis(5000);
+		assertEquals(HttpStatus.NOT_FOUND, this.response.getStatusCode());
+	}
+
+	@Test
+	public void directoryInJarFile() throws Exception {
+		this.exchange.getAttributes().put(PATH_WITHIN_HANDLER_MAPPING_ATTRIBUTE, "underscorejs/");
+		this.handler.handle(this.exchange).blockMillis(5000);
+
+		assertNull(this.response.getStatusCode());
+		assertEquals(0, this.response.getHeaders().getContentLength());
+	}
+
+	@Test
+	public void missingResourcePath() throws Exception {
+		this.exchange.getAttributes().put(PATH_WITHIN_HANDLER_MAPPING_ATTRIBUTE, "");
+		this.handler.handle(this.exchange).blockMillis(5000);
+		assertEquals(HttpStatus.NOT_FOUND, this.response.getStatusCode());
+	}
+
+	@Test(expected = IllegalStateException.class)
+	public void noPathWithinHandlerMappingAttribute() throws Exception {
+		this.handler.handle(this.exchange).blockMillis(5000);
+	}
+
+	@Test(expected = MethodNotAllowedException.class)
+	public void unsupportedHttpMethod() throws Exception {
+		this.exchange.getAttributes().put(PATH_WITHIN_HANDLER_MAPPING_ATTRIBUTE, "foo.css");
+		this.request.setHttpMethod(HttpMethod.POST);
+		this.handler.handle(this.exchange).blockMillis(5000);
+	}
+
+	@Test
+	public void resourceNotFound() throws Exception {
+		for (HttpMethod method : HttpMethod.values()) {
+			this.request = new MockServerHttpRequest(HttpMethod.GET, "");
+			this.response = new MockServerHttpResponse();
+			this.exchange = new DefaultServerWebExchange(this.request, this.response, this.sessionManager);
+			resourceNotFound(method);
+		}
+	}
+
+	private void resourceNotFound(HttpMethod httpMethod) throws Exception {
+		this.request.setHttpMethod(httpMethod);
+		this.exchange.getAttributes().put(PATH_WITHIN_HANDLER_MAPPING_ATTRIBUTE, "not-there.css");
+		this.handler.handle(this.exchange).blockMillis(5000);
+		assertEquals(HttpStatus.NOT_FOUND, this.response.getStatusCode());
+	}
+
+	@Test
+	@Ignore
+	public void partialContentByteRange() throws Exception {
+		this.request.addHeader("Range", "bytes=0-1");
+		this.exchange.getAttributes().put(PATH_WITHIN_HANDLER_MAPPING_ATTRIBUTE, "foo.txt");
+		this.handler.handle(this.exchange).blockMillis(5000);
+
+		assertEquals(HttpStatus.PARTIAL_CONTENT, this.response.getStatusCode());
+		assertEquals(MediaType.TEXT_PLAIN, this.response.getHeaders().getContentType());
+		assertEquals(2, this.response.getHeaders().getContentLength());
+		assertEquals("bytes 0-1/10", this.response.getHeaders().getFirst("Content-Range"));
+		assertEquals("bytes", this.response.getHeaders().getFirst("Accept-Ranges"));
+		assertEquals(1, this.response.getHeaders().get("Accept-Ranges").size());
+		assertResponseBody("So");
+	}
+
+	@Test
+	@Ignore
+	public void partialContentByteRangeNoEnd() throws Exception {
+		this.request.addHeader("Range", "bytes=9-");
+		this.exchange.getAttributes().put(PATH_WITHIN_HANDLER_MAPPING_ATTRIBUTE, "foo.txt");
+		this.handler.handle(this.exchange).blockMillis(5000);
+
+		assertEquals(HttpStatus.PARTIAL_CONTENT, this.response.getStatusCode());
+		assertEquals(MediaType.TEXT_PLAIN, this.response.getHeaders().getContentType());
+		assertEquals(1, this.response.getHeaders().getContentLength());
+		assertEquals("bytes 9-9/10", this.response.getHeaders().getFirst("Content-Range"));
+		assertEquals("bytes", this.response.getHeaders().getFirst("Accept-Ranges"));
+		assertEquals(1, this.response.getHeaders().get("Accept-Ranges").size());
+		assertResponseBody(".");
+	}
+
+	@Test
+	@Ignore
+	public void partialContentByteRangeLargeEnd() throws Exception {
+		this.request.addHeader("Range", "bytes=9-10000");
+		this.exchange.getAttributes().put(PATH_WITHIN_HANDLER_MAPPING_ATTRIBUTE, "foo.txt");
+		this.handler.handle(this.exchange).blockMillis(5000);
+
+		assertEquals(HttpStatus.PARTIAL_CONTENT, this.response.getStatusCode());
+		assertEquals(MediaType.TEXT_PLAIN, this.response.getHeaders().getContentType());
+		assertEquals(1, this.response.getHeaders().getContentLength());
+		assertEquals("bytes 9-9/10", this.response.getHeaders().getFirst("Content-Range"));
+		assertEquals("bytes", this.response.getHeaders().getFirst("Accept-Ranges"));
+		assertEquals(1, this.response.getHeaders().get("Accept-Ranges").size());
+		assertResponseBody(".");
+	}
+
+	@Test
+	@Ignore
+	public void partialContentSuffixRange() throws Exception {
+		this.request.addHeader("Range", "bytes=-1");
+		this.exchange.getAttributes().put(PATH_WITHIN_HANDLER_MAPPING_ATTRIBUTE, "foo.txt");
+		this.handler.handle(this.exchange).blockMillis(5000);
+
+		assertEquals(HttpStatus.PARTIAL_CONTENT, this.response.getStatusCode());
+		assertEquals(MediaType.TEXT_PLAIN, this.response.getHeaders().getContentType());
+		assertEquals(1, this.response.getHeaders().getContentLength());
+		assertEquals("bytes 9-9/10", this.response.getHeaders().getFirst("Content-Range"));
+		assertEquals("bytes", this.response.getHeaders().getFirst("Accept-Ranges"));
+		assertEquals(1, this.response.getHeaders().get("Accept-Ranges").size());
+		assertResponseBody(".");
+	}
+
+	@Test
+	@Ignore
+	public void partialContentSuffixRangeLargeSuffix() throws Exception {
+		this.request.addHeader("Range", "bytes=-11");
+		this.exchange.getAttributes().put(PATH_WITHIN_HANDLER_MAPPING_ATTRIBUTE, "foo.txt");
+		this.handler.handle(this.exchange).blockMillis(5000);
+
+		assertEquals(HttpStatus.PARTIAL_CONTENT, this.response.getStatusCode());
+		assertEquals(MediaType.TEXT_PLAIN, this.response.getHeaders().getContentType());
+		assertEquals(10, this.response.getHeaders().getContentLength());
+		assertEquals("bytes 0-9/10", this.response.getHeaders().getFirst("Content-Range"));
+		assertEquals("bytes", this.response.getHeaders().getFirst("Accept-Ranges"));
+		assertEquals(1, this.response.getHeaders().get("Accept-Ranges").size());
+		assertResponseBody("Some text.");
+	}
+
+	@Test
+	@Ignore
+	public void partialContentInvalidRangeHeader() throws Exception {
+		this.request.addHeader("Range", "bytes= foo bar");
+		this.exchange.getAttributes().put(PATH_WITHIN_HANDLER_MAPPING_ATTRIBUTE, "foo.txt");
+		this.handler.handle(this.exchange).blockMillis(5000);
+
+		assertEquals(HttpStatus.REQUESTED_RANGE_NOT_SATISFIABLE, this.response.getStatusCode());
+		assertEquals("bytes */10", this.response.getHeaders().getFirst("Content-Range"));
+		assertEquals("bytes", this.response.getHeaders().getFirst("Accept-Ranges"));
+		assertEquals(1, this.response.getHeaders().get("Accept-Ranges").size());
+	}
+
+	@Test
+	@Ignore
+	public void partialContentMultipleByteRanges() throws Exception {
+		this.request.addHeader("Range", "bytes=0-1, 4-5, 8-9");
+		this.exchange.getAttributes().put(PATH_WITHIN_HANDLER_MAPPING_ATTRIBUTE, "foo.txt");
+		this.handler.handle(this.exchange).blockMillis(5000);
+
+		assertEquals(HttpStatus.PARTIAL_CONTENT, this.response.getStatusCode());
+		assertTrue(this.response.getHeaders().getContentType().toString()
+				.startsWith("multipart/byteranges; boundary="));
+
+		String boundary = "--" + this.response.getHeaders().getContentType().toString().substring(31);
+
+		TestSubscriber.subscribe(this.response.getBody())
+				.assertValuesWith(buf -> {
+
+					String content = DataBufferTestUtils.dumpString(buf, StandardCharsets.UTF_8);
+					String[] ranges = StringUtils.tokenizeToStringArray(content, "\r\n", false, true);
+
+					assertEquals(boundary, ranges[0]);
+					assertEquals("Content-Type: text/plain", ranges[1]);
+					assertEquals("Content-Range: bytes 0-1/10", ranges[2]);
+					assertEquals("So", ranges[3]);
+
+					assertEquals(boundary, ranges[4]);
+					assertEquals("Content-Type: text/plain", ranges[5]);
+					assertEquals("Content-Range: bytes 4-5/10", ranges[6]);
+					assertEquals(" t", ranges[7]);
+
+					assertEquals(boundary, ranges[8]);
+					assertEquals("Content-Type: text/plain", ranges[9]);
+					assertEquals("Content-Range: bytes 8-9/10", ranges[10]);
+					assertEquals("t.", ranges[11]);
+
+				});
+	}
+
+	@Test // SPR-14005
+	public void doOverwriteExistingCacheControlHeaders() throws Exception {
+		this.exchange.getAttributes().put(PATH_WITHIN_HANDLER_MAPPING_ATTRIBUTE, "foo.css");
+		this.response.getHeaders().setCacheControl(CacheControl.noStore().getHeaderValue());
+
+		this.handler.handle(this.exchange).blockMillis(5000);
+
+		assertEquals("max-age=3600", this.response.getHeaders().getCacheControl());
+	}
+
+	private long resourceLastModified(String resourceName) throws IOException {
+		return new ClassPathResource(resourceName, getClass()).getFile().lastModified();
+	}
+
+	private long resourceLastModifiedDate(String resourceName) throws IOException {
+		return new ClassPathResource(resourceName, getClass()).getFile().lastModified();
+	}
+
+	private void assertResponseBody(String responseBody) {
+		TestSubscriber.subscribe(this.response.getBody())
+				.assertValuesWith(buf -> assertEquals(responseBody,
+						DataBufferTestUtils.dumpString(buf, StandardCharsets.UTF_8)));
+	}
+
+}

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

@@ -0,0 +1,206 @@
+/*
+ * 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.
+ * 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.resource;
+
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+
+import org.hamcrest.Matchers;
+import org.junit.Before;
+import org.junit.Test;
+
+import org.springframework.core.io.ClassPathResource;
+import org.springframework.core.io.Resource;
+import org.springframework.http.HttpMethod;
+import org.springframework.mock.http.server.reactive.test.MockServerHttpRequest;
+import org.springframework.mock.http.server.reactive.test.MockServerHttpResponse;
+import org.springframework.web.server.ServerWebExchange;
+import org.springframework.web.server.adapter.DefaultServerWebExchange;
+import org.springframework.web.server.session.DefaultWebSessionManager;
+
+import static org.hamcrest.Matchers.instanceOf;
+import static org.hamcrest.Matchers.is;
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertNull;
+import static org.junit.Assert.assertThat;
+import static org.mockito.BDDMockito.given;
+import static org.mockito.BDDMockito.mock;
+import static org.mockito.BDDMockito.never;
+import static org.mockito.BDDMockito.times;
+import static org.mockito.BDDMockito.verify;
+
+/**
+ * Unit tests for {@link VersionResourceResolver}.
+ * @author Rossen Stoyanchev
+ * @author Brian Clozel
+ */
+public class VersionResourceResolverTests {
+
+	private List<Resource> locations;
+
+	private VersionResourceResolver resolver;
+
+	private ResourceResolverChain chain;
+
+	private VersionStrategy versionStrategy;
+
+
+	@Before
+	public void setup() {
+		this.locations = new ArrayList<>();
+		this.locations.add(new ClassPathResource("test/", getClass()));
+		this.locations.add(new ClassPathResource("testalternatepath/", getClass()));
+
+		this.resolver = new VersionResourceResolver();
+		this.chain = mock(ResourceResolverChain.class);
+		this.versionStrategy = mock(VersionStrategy.class);
+	}
+
+	@Test
+	public void resolveResourceExisting() throws Exception {
+		String file = "bar.css";
+		Resource expected = new ClassPathResource("test/" + file, getClass());
+		given(this.chain.resolveResource(null, file, this.locations)).willReturn(expected);
+
+		this.resolver.setStrategyMap(Collections.singletonMap("/**", this.versionStrategy));
+		Resource actual = this.resolver.resolveResourceInternal(null, file, this.locations, this.chain);
+		assertEquals(expected, actual);
+		verify(this.chain, times(1)).resolveResource(null, file, this.locations);
+		verify(this.versionStrategy, never()).extractVersion(file);
+	}
+
+	@Test
+	public void resolveResourceNoVersionStrategy() throws Exception {
+		String file = "missing.css";
+		given(this.chain.resolveResource(null, file, this.locations)).willReturn(null);
+
+		this.resolver.setStrategyMap(Collections.emptyMap());
+		Resource actual = this.resolver.resolveResourceInternal(null, file, this.locations, this.chain);
+		assertNull(actual);
+		verify(this.chain, times(1)).resolveResource(null, file, this.locations);
+	}
+
+	@Test
+	public void resolveResourceNoVersionInPath() throws Exception {
+		String file = "bar.css";
+		given(this.chain.resolveResource(null, file, this.locations)).willReturn(null);
+		given(this.versionStrategy.extractVersion(file)).willReturn("");
+
+		this.resolver.setStrategyMap(Collections.singletonMap("/**", this.versionStrategy));
+		Resource actual = this.resolver.resolveResourceInternal(null, file, this.locations, this.chain);
+		assertNull(actual);
+		verify(this.chain, times(1)).resolveResource(null, file, this.locations);
+		verify(this.versionStrategy, times(1)).extractVersion(file);
+	}
+
+	@Test
+	public void resolveResourceNoResourceAfterVersionRemoved() throws Exception {
+		String versionFile = "bar-version.css";
+		String version = "version";
+		String file = "bar.css";
+		given(this.chain.resolveResource(null, versionFile, this.locations)).willReturn(null);
+		given(this.chain.resolveResource(null, file, this.locations)).willReturn(null);
+		given(this.versionStrategy.extractVersion(versionFile)).willReturn(version);
+		given(this.versionStrategy.removeVersion(versionFile, version)).willReturn(file);
+
+		this.resolver.setStrategyMap(Collections.singletonMap("/**", this.versionStrategy));
+		Resource actual = this.resolver.resolveResourceInternal(null, versionFile, this.locations, this.chain);
+		assertNull(actual);
+		verify(this.versionStrategy, times(1)).removeVersion(versionFile, version);
+	}
+
+	@Test
+	public void resolveResourceVersionDoesNotMatch() throws Exception {
+		String versionFile = "bar-version.css";
+		String version = "version";
+		String file = "bar.css";
+		Resource expected = new ClassPathResource("test/" + file, getClass());
+		given(this.chain.resolveResource(null, versionFile, this.locations)).willReturn(null);
+		given(this.chain.resolveResource(null, file, this.locations)).willReturn(expected);
+		given(this.versionStrategy.extractVersion(versionFile)).willReturn(version);
+		given(this.versionStrategy.removeVersion(versionFile, version)).willReturn(file);
+		given(this.versionStrategy.getResourceVersion(expected)).willReturn("newer-version");
+
+		this.resolver.setStrategyMap(Collections.singletonMap("/**", this.versionStrategy));
+		Resource actual = this.resolver.resolveResourceInternal(null, versionFile, this.locations, this.chain);
+		assertNull(actual);
+		verify(this.versionStrategy, times(1)).getResourceVersion(expected);
+	}
+
+	@Test
+	public void resolveResourceSuccess() throws Exception {
+		String versionFile = "bar-version.css";
+		String version = "version";
+		String file = "bar.css";
+		Resource expected = new ClassPathResource("test/" + file, getClass());
+		MockServerHttpRequest request = new MockServerHttpRequest(HttpMethod.GET, "/resources/bar-version.css");
+		MockServerHttpResponse response = new MockServerHttpResponse();
+		DefaultWebSessionManager sessionManager = new DefaultWebSessionManager();
+		ServerWebExchange exchange = new DefaultServerWebExchange(request, response, sessionManager);
+		given(this.chain.resolveResource(exchange, versionFile, this.locations)).willReturn(null);
+		given(this.chain.resolveResource(exchange, file, this.locations)).willReturn(expected);
+		given(this.versionStrategy.extractVersion(versionFile)).willReturn(version);
+		given(this.versionStrategy.removeVersion(versionFile, version)).willReturn(file);
+		given(this.versionStrategy.getResourceVersion(expected)).willReturn(version);
+
+		this.resolver.setStrategyMap(Collections.singletonMap("/**", this.versionStrategy));
+		Resource actual = this.resolver.resolveResourceInternal(exchange, versionFile, this.locations, this.chain);
+		assertEquals(expected.getFilename(), actual.getFilename());
+		verify(this.versionStrategy, times(1)).getResourceVersion(expected);
+		assertThat(actual, instanceOf(VersionedResource.class));
+		assertEquals(version, ((VersionedResource)actual).getVersion());
+	}
+
+	@Test
+	public void getStrategyForPath() throws Exception {
+		Map<String, VersionStrategy> strategies = new HashMap<>();
+		VersionStrategy jsStrategy = mock(VersionStrategy.class);
+		VersionStrategy catchAllStrategy = mock(VersionStrategy.class);
+		strategies.put("/**", catchAllStrategy);
+		strategies.put("/**/*.js", jsStrategy);
+		this.resolver.setStrategyMap(strategies);
+
+		assertEquals(catchAllStrategy, this.resolver.getStrategyForPath("foo.css"));
+		assertEquals(catchAllStrategy, this.resolver.getStrategyForPath("foo-js.css"));
+		assertEquals(jsStrategy, this.resolver.getStrategyForPath("foo.js"));
+		assertEquals(jsStrategy, this.resolver.getStrategyForPath("bar/foo.js"));
+	}
+
+	@Test // SPR-13883
+	public void shouldConfigureFixedPrefixAutomatically() throws Exception {
+
+		this.resolver.addFixedVersionStrategy("fixedversion", "/js/**", "/css/**", "/fixedversion/css/**");
+
+		assertThat(this.resolver.getStrategyMap().size(), is(4));
+
+		assertThat(this.resolver.getStrategyForPath("js/something.js"),
+				Matchers.instanceOf(FixedVersionStrategy.class));
+
+		assertThat(this.resolver.getStrategyForPath("fixedversion/js/something.js"),
+				Matchers.instanceOf(FixedVersionStrategy.class));
+
+		assertThat(this.resolver.getStrategyForPath("css/something.css"),
+				Matchers.instanceOf(FixedVersionStrategy.class));
+
+		assertThat(this.resolver.getStrategyForPath("fixedversion/css/something.css"),
+				Matchers.instanceOf(FixedVersionStrategy.class));
+	}
+
+
+}

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

@@ -0,0 +1,165 @@
+/*
+ * 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.
+ * 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.resource;
+
+import java.util.Collections;
+import java.util.List;
+
+import org.junit.Before;
+import org.junit.Test;
+
+import org.springframework.core.io.ClassPathResource;
+import org.springframework.core.io.Resource;
+import org.springframework.http.HttpMethod;
+import org.springframework.http.server.reactive.ServerHttpResponse;
+import org.springframework.mock.http.server.reactive.test.MockServerHttpRequest;
+import org.springframework.mock.http.server.reactive.test.MockServerHttpResponse;
+import org.springframework.web.server.ServerWebExchange;
+import org.springframework.web.server.adapter.DefaultServerWebExchange;
+import org.springframework.web.server.session.DefaultWebSessionManager;
+import org.springframework.web.server.session.WebSessionManager;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertNull;
+import static org.mockito.BDDMockito.given;
+import static org.mockito.BDDMockito.mock;
+import static org.mockito.BDDMockito.never;
+import static org.mockito.BDDMockito.times;
+import static org.mockito.BDDMockito.verify;
+
+/**
+ * Unit tests for {@link WebJarsResourceResolver}.
+ *
+ * @author Rossen Stoyanchev
+ * @author Brian Clozel
+ */
+public class WebJarsResourceResolverTests {
+
+	private List<Resource> locations;
+
+	private WebJarsResourceResolver resolver;
+
+	private ResourceResolverChain chain;
+
+	private ServerWebExchange exchange;
+
+
+	@Before
+	public void setup() {
+		// for this to work, an actual WebJar must be on the test classpath
+		this.locations = Collections.singletonList(new ClassPathResource("/META-INF/resources/webjars"));
+		this.resolver = new WebJarsResourceResolver();
+		this.chain = mock(ResourceResolverChain.class);
+
+		MockServerHttpRequest request = new MockServerHttpRequest(HttpMethod.GET, "");
+		ServerHttpResponse response = new MockServerHttpResponse();
+		WebSessionManager manager = new DefaultWebSessionManager();
+		this.exchange = new DefaultServerWebExchange(request, response, manager);
+	}
+
+
+	@Test
+	public void resolveUrlExisting() {
+		this.locations = Collections.singletonList(new ClassPathResource("/META-INF/resources/webjars/", getClass()));
+		String file = "/foo/2.3/foo.txt";
+		given(this.chain.resolveUrlPath(file, this.locations)).willReturn(file);
+
+		String actual = this.resolver.resolveUrlPath(file, this.locations, this.chain);
+
+		assertEquals(file, actual);
+		verify(this.chain, times(1)).resolveUrlPath(file, this.locations);
+	}
+
+	@Test
+	public void resolveUrlExistingNotInJarFile() {
+		this.locations = Collections.singletonList(new ClassPathResource("/META-INF/resources/webjars/", getClass()));
+		String file = "foo/foo.txt";
+		given(this.chain.resolveUrlPath(file, this.locations)).willReturn(null);
+
+		String actual = this.resolver.resolveUrlPath(file, this.locations, this.chain);
+
+		assertNull(actual);
+		verify(this.chain, times(1)).resolveUrlPath(file, this.locations);
+		verify(this.chain, never()).resolveUrlPath("foo/2.3/foo.txt", this.locations);
+	}
+
+	@Test
+	public void resolveUrlWebJarResource() {
+		String file = "underscorejs/underscore.js";
+		String expected = "underscorejs/1.8.3/underscore.js";
+		given(this.chain.resolveUrlPath(file, this.locations)).willReturn(null);
+		given(this.chain.resolveUrlPath(expected, this.locations)).willReturn(expected);
+
+		String actual = this.resolver.resolveUrlPath(file, this.locations, this.chain);
+
+		assertEquals(expected, actual);
+		verify(this.chain, times(1)).resolveUrlPath(file, this.locations);
+		verify(this.chain, times(1)).resolveUrlPath(expected, this.locations);
+	}
+
+	@Test
+	public void resolveUrlWebJarResourceNotFound() {
+		String file = "something/something.js";
+		given(this.chain.resolveUrlPath(file, this.locations)).willReturn(null);
+
+		String actual = this.resolver.resolveUrlPath(file, this.locations, this.chain);
+
+		assertNull(actual);
+		verify(this.chain, times(1)).resolveUrlPath(file, this.locations);
+		verify(this.chain, never()).resolveUrlPath(null, this.locations);
+	}
+
+	@Test
+	public void resolveResourceExisting() {
+		Resource expected = mock(Resource.class);
+		this.locations = Collections.singletonList(new ClassPathResource("/META-INF/resources/webjars/", getClass()));
+		String file = "foo/2.3/foo.txt";
+		given(this.chain.resolveResource(this.exchange, file, this.locations)).willReturn(expected);
+
+		Resource actual = this.resolver.resolveResource(this.exchange, file, this.locations, this.chain);
+
+		assertEquals(expected, actual);
+		verify(this.chain, times(1)).resolveResource(this.exchange, file, this.locations);
+	}
+
+	@Test
+	public void resolveResourceNotFound() {
+		String file = "something/something.js";
+		given(this.chain.resolveUrlPath(file, this.locations)).willReturn(null);
+
+		Resource actual = this.resolver.resolveResource(this.exchange, file, this.locations, this.chain);
+
+		assertNull(actual);
+		verify(this.chain, times(1)).resolveResource(this.exchange, file, this.locations);
+		verify(this.chain, never()).resolveResource(this.exchange, null, this.locations);
+	}
+
+	@Test
+	public void resolveResourceWebJar() {
+		Resource expected = mock(Resource.class);
+		String file = "underscorejs/underscore.js";
+		String expectedPath = "underscorejs/1.8.3/underscore.js";
+		this.locations = Collections.singletonList(new ClassPathResource("/META-INF/resources/webjars/", getClass()));
+		given(this.chain.resolveResource(this.exchange, expectedPath, this.locations)).willReturn(expected);
+
+		Resource actual = this.resolver.resolveResource(this.exchange, file, this.locations, this.chain);
+
+		assertEquals(expected, actual);
+		verify(this.chain, times(1)).resolveResource(this.exchange, file, this.locations);
+	}
+
+}

spring-web-reactive/src/test/resources/org/springframework/web/reactive/resource/test/appcache.manifest

@@ -0,0 +1,17 @@
+CACHE MANIFEST
+
+# this is a comment
+CACHE:
+bar.css
+foo.css
+//example.org/style.css
+
+NETWORK:
+*
+
+CACHE:
+js/bar.js
+http://example.org/image.png
+
+FALLBACK:
+/main /static.html

spring-web-reactive/src/test/resources/org/springframework/web/reactive/resource/test/bar.css

@@ -0,0 +1 @@
+h2 { color:white; }

spring-web-reactive/src/test/resources/org/springframework/web/reactive/resource/test/error.manifest

@@ -0,0 +1,4 @@
+THIS DOES NOT START WITH "CACHE MANIFEST"
+
+CACHE:
+bar.css

spring-web-reactive/src/test/resources/org/springframework/web/reactive/resource/test/external.css

@@ -0,0 +1,3 @@
+@import url("http://example.org/fonts/css");
+body { background: url("file:///home/spring/image.png") }
+figure { background: url("//example.org/style.css")}

spring-web-reactive/src/test/resources/org/springframework/web/reactive/resource/test/foo-e36d2e05253c6c7085a91522ce43a0b4.css

@@ -0,0 +1 @@
+h1 { color:red; }

spring-web-reactive/src/test/resources/org/springframework/web/reactive/resource/test/foo.css

@@ -0,0 +1 @@
+h1 { color:red; }

spring-web-reactive/src/test/resources/org/springframework/web/reactive/resource/test/foo.html

@@ -0,0 +1,10 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
+<html>
+<head>
+<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
+<title>Foo</title>
+</head>
+<body>
+
+</body>
+</html>

spring-web-reactive/src/test/resources/org/springframework/web/reactive/resource/test/js/bar.js

@@ -0,0 +1 @@
+function foo() { console.log("hello bar"); }

spring-web-reactive/src/test/resources/org/springframework/web/reactive/resource/test/js/foo.js

@@ -0,0 +1 @@
+function foo() { console.log("hello world"); }

spring-web-reactive/src/test/resources/org/springframework/web/reactive/resource/test/main.css

@@ -0,0 +1,9 @@
+
+@import url("bar.css");
+@import url('bar.css');
+@import url(bar.css);
+
+@import "foo.css";
+@import 'foo.css';
+
+body { background: url("images/image.png") }

spring-web-reactive/src/test/resources/org/springframework/web/reactive/resource/testalternatepath/bar.css

@@ -0,0 +1 @@
+fail

spring-web-reactive/src/test/resources/org/springframework/web/reactive/resource/testalternatepath/baz.css

@@ -0,0 +1 @@
+h1 { color:red; }

spring-web-reactive/src/test/resources/org/springframework/web/reactive/resource/testalternatepath/js/baz.js

@@ -0,0 +1 @@
+function foo() { console.log("hello world"); }

spring-web-reactive/src/test/resources/org/springframework/web/reactive/resource/testsecret/secret.txt

@@ -0,0 +1 @@
+big secret