org.springframework.web.reactive.resource.ContentVersionStrategy Maven / Gradle / Ivy
/*
* Copyright 2002-2018 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 reactor.core.publisher.Flux;
import reactor.core.publisher.Mono;
import org.springframework.core.io.Resource;
import org.springframework.core.io.buffer.DataBuffer;
import org.springframework.core.io.buffer.DataBufferFactory;
import org.springframework.core.io.buffer.DataBufferUtils;
import org.springframework.core.io.buffer.DefaultDataBufferFactory;
import org.springframework.util.DigestUtils;
import org.springframework.util.StreamUtils;
/**
* 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 AbstractFileNameVersionStrategy {
private static final DataBufferFactory dataBufferFactory = new DefaultDataBufferFactory();
@Override
public Mono getResourceVersion(Resource resource) {
Flux flux =
DataBufferUtils.read(resource, dataBufferFactory, StreamUtils.BUFFER_SIZE);
return DataBufferUtils.join(flux)
.map(buffer -> {
byte[] result = new byte[buffer.readableByteCount()];
buffer.read(result);
DataBufferUtils.release(buffer);
return DigestUtils.md5DigestAsHex(result);
});
}
}