/*
* 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.Collections;
import reactor.core.publisher.Mono;
import org.springframework.core.io.Resource;
import org.springframework.http.server.reactive.ServerHttpRequest;
import org.springframework.util.StringUtils;
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 Mono<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) : Mono.empty());
}
else {
// try resolving as relative path
return transformerChain.getResolverChain()
.resolveUrlPath(resourcePath, Collections.singletonList(resource));
}
}
/**
* Transform the given relative request path to an absolute path,
* taking the path of the given request as a point of reference.
* The resulting path is also cleaned from sequences like "path/..".
*
* @param path the relative path to transform
* @param exchange the current exchange
* @return the absolute request path for the given resource path
*/
protected String toAbsolutePath(String path, ServerWebExchange exchange) {
String requestPath = exchange.getRequest().getURI().getPath();
String absolutePath = StringUtils.applyRelativePath(requestPath, path);
return StringUtils.cleanPath(absolutePath);
}
}