/*
* 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.servlet.config.annotation;
import java.util.ArrayList;
import java.util.List;
import org.springframework.cache.Cache;
import org.springframework.core.io.Resource;
import org.springframework.core.io.ResourceLoader;
import org.springframework.util.Assert;
import org.springframework.http.CacheControl;
import org.springframework.web.servlet.resource.PathResourceResolver;
import org.springframework.web.servlet.resource.ResourceHttpRequestHandler;
/**
* Encapsulates information required to create a resource handler.
*
* @author Rossen Stoyanchev
* @author Keith Donald
* @author Brian Clozel
* @since 3.1
*/
public class ResourceHandlerRegistration {
private final ResourceLoader resourceLoader;
private final String[] pathPatterns;
private final List<Resource> locations = new ArrayList<>();
private Integer cachePeriod;
private CacheControl cacheControl;
private ResourceChainRegistration resourceChainRegistration;
/**
* Create a {@link ResourceHandlerRegistration} instance.
* @param resourceLoader a resource loader for turning a String location into a {@link Resource}
* @param pathPatterns one or more resource URL path patterns
*/
public ResourceHandlerRegistration(ResourceLoader resourceLoader, String... pathPatterns) {
Assert.notEmpty(pathPatterns, "At least one path pattern is required for resource handling.");
this.resourceLoader = resourceLoader;
this.pathPatterns = pathPatterns;
}
/**
* Add one or more resource locations from which to serve static content. Each location must point to a valid
* directory. Multiple locations may be specified as a comma-separated list, and the locations will be checked
* for a given resource in the order specified.
* <p>For example, {{@code "/"}, {@code "classpath:/META-INF/public-web-resources/"}} allows resources to
* be served both from the web application root and from any JAR on the classpath that contains a
* {@code /META-INF/public-web-resources/} directory, with resources in the web application root taking precedence.
* @return the same {@link ResourceHandlerRegistration} instance, for chained method invocation
*/
public ResourceHandlerRegistration addResourceLocations(String... resourceLocations) {
for (String location : resourceLocations) {
this.locations.add(resourceLoader.getResource(location));
}
return this;
}
/**
* Specify the cache period for the resources served by the resource handler, in seconds. The default is to not
* send any cache headers but to rely on last-modified timestamps only. Set to 0 in order to send cache headers
* that prevent caching, or to a positive number of seconds to send cache headers with the given max-age value.
* @param cachePeriod the time to cache resources in seconds
* @return the same {@link ResourceHandlerRegistration} instance, for chained method invocation
*/
public ResourceHandlerRegistration setCachePeriod(Integer cachePeriod) {
this.cachePeriod = cachePeriod;
return this;
}
/**
* Specify the {@link org.springframework.http.CacheControl} which should be used
* by the resource handler.
*
* <p>Setting a custom value here will override the configuration set with {@link #setCachePeriod}.
*
* @param cacheControl the CacheControl configuration to use
* @return the same {@link ResourceHandlerRegistration} instance, for chained method invocation
* @since 4.2
*/
public ResourceHandlerRegistration setCacheControl(CacheControl cacheControl) {
this.cacheControl = cacheControl;
return this;
}
/**
* Configure a chain of resource resolvers and transformers to use. This
* can be useful, for example, to apply a version strategy to resource URLs.
*
* <p>If this method is not invoked, by default only a simple
* {@link PathResourceResolver} is used in order to match URL paths to
* resources under the configured locations.
*
* @param cacheResources whether to cache the result of resource resolution;
* setting this to "true" is recommended for production (and "false" for
* development, especially when applying a version strategy)
* @return the same {@link ResourceHandlerRegistration} instance, for chained method invocation
* @since 4.1
*/
public ResourceChainRegistration resourceChain(boolean cacheResources) {
this.resourceChainRegistration = new ResourceChainRegistration(cacheResources);
return this.resourceChainRegistration;
}
/**
* Configure a chain of resource resolvers and transformers to use. This
* can be useful, for example, to apply a version strategy to resource URLs.
*
* <p>If this method is not invoked, by default only a simple
* {@link PathResourceResolver} is used in order to match URL paths to
* resources under the configured locations.
*
* @param cacheResources whether to cache the result of resource resolution;
* setting this to "true" is recommended for production (and "false" for
* development, especially when applying a version strategy
* @param cache the cache to use for storing resolved and transformed resources;
* by default a {@link org.springframework.cache.concurrent.ConcurrentMapCache}
* is used. Since Resources aren't serializable and can be dependent on the
* application host, one should not use a distributed cache but rather an
* in-memory cache.
* @return the same {@link ResourceHandlerRegistration} instance, for chained method invocation
* @since 4.1
*/
public ResourceChainRegistration resourceChain(boolean cacheResources, Cache cache) {
this.resourceChainRegistration = new ResourceChainRegistration(cacheResources, cache);
return this.resourceChainRegistration;
}
/**
* Returns the URL path patterns for the resource handler.
*/
protected String[] getPathPatterns() {
return this.pathPatterns;
}
/**
* Returns a {@link ResourceHttpRequestHandler} instance.
*/
protected ResourceHttpRequestHandler getRequestHandler() {
ResourceHttpRequestHandler handler = new ResourceHttpRequestHandler();
if (this.resourceChainRegistration != null) {
handler.setResourceResolvers(this.resourceChainRegistration.getResourceResolvers());
handler.setResourceTransformers(this.resourceChainRegistration.getResourceTransformers());
}
handler.setLocations(this.locations);
if (this.cacheControl != null) {
handler.setCacheControl(this.cacheControl);
}
else if (this.cachePeriod != null) {
handler.setCacheSeconds(this.cachePeriod);
}
return handler;
}
}