org.springframework.web.reactive.resource.CachingResourceResolver Maven / Gradle / Ivy
/*
* 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 reactor.core.publisher.Mono;
import org.springframework.cache.Cache;
import org.springframework.cache.CacheManager;
import org.springframework.core.io.Resource;
import org.springframework.lang.Nullable;
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(Cache cache) {
Assert.notNull(cache, "Cache is required");
this.cache = cache;
}
public CachingResourceResolver(CacheManager cacheManager, String cacheName) {
Cache cache = cacheManager.getCache(cacheName);
if (cache == null) {
throw new IllegalArgumentException("Cache '" + cacheName + "' not found");
}
this.cache = cache;
}
/**
* Return the configured {@code Cache}.
*/
public Cache getCache() {
return this.cache;
}
@Override
protected Mono resolveResourceInternal(@Nullable ServerWebExchange exchange,
String requestPath, List locations, ResourceResolverChain chain) {
String key = computeKey(exchange, requestPath);
Resource cachedResource = this.cache.get(key, Resource.class);
if (cachedResource != null) {
if (logger.isTraceEnabled()) {
logger.trace("Found match: " + cachedResource);
}
return Mono.just(cachedResource);
}
return chain.resolveResource(exchange, requestPath, locations)
.doOnNext(resource -> {
if (logger.isTraceEnabled()) {
logger.trace("Putting resolved resource in cache: " + resource);
}
this.cache.put(key, resource);
});
}
protected String computeKey(@Nullable 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 Mono resolveUrlPathInternal(String resourceUrlPath,
List locations, ResourceResolverChain chain) {
String key = RESOLVED_URL_PATH_CACHE_KEY_PREFIX + resourceUrlPath;
String cachedUrlPath = this.cache.get(key, String.class);
if (cachedUrlPath != null) {
if (logger.isTraceEnabled()) {
logger.trace("Found match: \"" + cachedUrlPath + "\"");
}
return Mono.just(cachedUrlPath);
}
return chain.resolveUrlPath(resourceUrlPath, locations)
.doOnNext(resolvedPath -> {
if (logger.isTraceEnabled()) {
logger.trace("Putting resolved resource URL path in cache: \"" + resolvedPath + "\"");
}
this.cache.put(key, resolvedPath);
});
}
}