Java tutorial
/* * Copyright 2002-2017 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.LinkedHashMap; import java.util.List; import java.util.Map; import org.apache.commons.logging.Log; import org.apache.commons.logging.LogFactory; import reactor.core.publisher.Mono; 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.PathContainer; import org.springframework.http.server.reactive.ServerHttpRequest; import org.springframework.util.StringUtils; import org.springframework.web.reactive.handler.SimpleUrlHandlerMapping; import org.springframework.web.server.ServerWebExchange; import org.springframework.web.util.pattern.PathPattern; import org.springframework.web.util.pattern.PathPatternParser; /** * 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 WebFlux 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> { private static final Log logger = LogFactory.getLog(ResourceUrlProvider.class); private final PathPatternParser patternParser = new PathPatternParser(); private final Map<PathPattern, ResourceWebHandler> handlerMap = new LinkedHashMap<>(); /** * Return a read-only view of the resource handler mappings either manually * configured or auto-detected from Spring configuration. */ public Map<PathPattern, ResourceWebHandler> getHandlerMap() { return Collections.unmodifiableMap(this.handlerMap); } /** * Manually configure resource handler mappings. * <p><strong>Note:</strong> by default resource mappings are auto-detected * from the Spring {@code ApplicationContext}. If this property is used, * auto-detection is turned off. */ public void registerHandlers(Map<String, ResourceWebHandler> handlerMap) { this.handlerMap.clear(); handlerMap.forEach((rawPattern, resourceWebHandler) -> { rawPattern = prependLeadingSlash(rawPattern); PathPattern pattern = this.patternParser.parse(rawPattern); this.handlerMap.put(pattern, resourceWebHandler); }); } private static String prependLeadingSlash(String pattern) { if (StringUtils.hasLength(pattern) && !pattern.startsWith("/")) { return "/" + pattern; } else { return pattern; } } @Override public void onApplicationEvent(ContextRefreshedEvent event) { if (this.handlerMap.isEmpty()) { detectResourceHandlers(event.getApplicationContext()); if (logger.isDebugEnabled()) { logger.debug("No resource handling mappings found"); } } } private void detectResourceHandlers(ApplicationContext context) { logger.debug("Looking for resource handler mappings"); Map<String, SimpleUrlHandlerMapping> beans = context.getBeansOfType(SimpleUrlHandlerMapping.class); List<SimpleUrlHandlerMapping> mappings = new ArrayList<>(beans.values()); AnnotationAwareOrderComparator.sort(mappings); mappings.forEach(mapping -> { mapping.getHandlerMap().forEach((pattern, handler) -> { 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); } }); }); } /** * Get the public resource URL for the given URI string. * <p>The URI string is expected to be a path and if it contains a query or * fragment those will be preserved in the resulting public resource URL. * @param uriString the URI string to transform * @param exchange the current exchange * @return the resolved public resource URL path, or empty if unresolved */ public final Mono<String> getForUriString(String uriString, ServerWebExchange exchange) { if (logger.isTraceEnabled()) { logger.trace("Getting resource URL for request URL \"" + uriString + "\""); } ServerHttpRequest request = exchange.getRequest(); int queryIndex = getQueryIndex(uriString); String lookupPath = uriString.substring(0, queryIndex); String query = uriString.substring(queryIndex); PathContainer parsedLookupPath = PathContainer.parsePath(lookupPath); if (logger.isTraceEnabled()) { logger.trace("Getting resource URL for lookup path \"" + lookupPath + "\""); } return resolveResourceUrl(parsedLookupPath) .map(resolvedPath -> request.getPath().contextPath().value() + resolvedPath + query); } private int getQueryIndex(String path) { int suffixIndex = path.length(); int queryIndex = path.indexOf("?"); if (queryIndex > 0) { suffixIndex = queryIndex; } int hashIndex = path.indexOf("#"); if (hashIndex > 0) { suffixIndex = Math.min(suffixIndex, hashIndex); } return suffixIndex; } private Mono<String> resolveResourceUrl(PathContainer lookupPath) { return this.handlerMap .entrySet().stream().filter(entry -> entry.getKey().matches(lookupPath)).sorted((entry1, entry2) -> PathPattern.SPECIFICITY_COMPARATOR.compare(entry1.getKey(), entry2.getKey())) .findFirst().map(entry -> { PathContainer path = entry.getKey().extractPathWithinPattern(lookupPath); int endIndex = lookupPath.elements().size() - path.elements().size(); PathContainer mapping = lookupPath.subPath(0, endIndex); if (logger.isTraceEnabled()) { logger.trace( "Invoking ResourceResolverChain for URL pattern " + "\"" + entry.getKey() + "\""); } ResourceWebHandler handler = entry.getValue(); List<ResourceResolver> resolvers = handler.getResourceResolvers(); ResourceResolverChain chain = new DefaultResourceResolverChain(resolvers); return chain.resolveUrlPath(path.value(), handler.getLocations()).map(resolvedPath -> { if (logger.isTraceEnabled()) { logger.trace("Resolved public resource URL path \"" + resolvedPath + "\""); } return mapping.value() + resolvedPath; }); }).orElse(Mono.empty()); } }