/*
* 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.http.converter.reactive;
import java.io.File;
import java.io.IOException;
import java.util.Optional;
import org.reactivestreams.Publisher;
import reactor.core.publisher.Flux;
import reactor.core.publisher.Mono;
import org.springframework.core.ResolvableType;
import org.springframework.core.codec.ResourceDecoder;
import org.springframework.core.codec.ResourceEncoder;
import org.springframework.core.io.InputStreamResource;
import org.springframework.core.io.Resource;
import org.springframework.core.io.support.ResourceUtils2;
import org.springframework.http.HttpHeaders;
import org.springframework.http.MediaType;
import org.springframework.http.ReactiveHttpOutputMessage;
import org.springframework.http.ZeroCopyHttpOutputMessage;
import org.springframework.http.support.MediaTypeUtils;
import org.springframework.util.MimeTypeUtils2;
/**
* Implementation of {@link HttpMessageConverter} that can read and write
* {@link Resource Resources} and supports byte range requests.
**
* @author Arjen Poutsma
*/
public class ResourceHttpMessageConverter extends CodecHttpMessageConverter<Resource> {
public ResourceHttpMessageConverter() {
super(new ResourceEncoder(), new ResourceDecoder());
}
public ResourceHttpMessageConverter(int bufferSize) {
super(new ResourceEncoder(bufferSize), new ResourceDecoder());
}
@Override
public Mono<Void> write(Publisher<? extends Resource> inputStream,
ResolvableType type, MediaType contentType,
ReactiveHttpOutputMessage outputMessage) {
return Mono.from(Flux.from(inputStream).
take(1).
concatMap(resource -> {
HttpHeaders headers = outputMessage.getHeaders();
addHeaders(headers, resource, contentType);
return writeContent(resource, type, contentType, outputMessage);
}));
}
protected void addHeaders(HttpHeaders headers, Resource resource,
MediaType contentType) {
if (headers.getContentType() == null) {
if (contentType == null ||
!contentType.isConcrete() ||
MediaType.APPLICATION_OCTET_STREAM.equals(contentType)) {
contentType = MimeTypeUtils2.getMimeType(resource.getFilename()).
map(MediaTypeUtils::toMediaType).
orElse(MediaType.APPLICATION_OCTET_STREAM);
}
headers.setContentType(contentType);
}
if (headers.getContentLength() < 0) {
contentLength(resource).ifPresent(headers::setContentLength);
}
}
private Mono<Void> writeContent(Resource resource, ResolvableType type,
MediaType contentType, ReactiveHttpOutputMessage outputMessage) {
if (outputMessage instanceof ZeroCopyHttpOutputMessage) {
Optional<File> file = getFile(resource);
if (file.isPresent()) {
ZeroCopyHttpOutputMessage zeroCopyResponse =
(ZeroCopyHttpOutputMessage) outputMessage;
return zeroCopyResponse
.writeWith(file.get(), (long) 0, file.get().length());
}
}
// non-zero copy fallback, using ResourceEncoder
return super.write(Mono.just(resource), type,
outputMessage.getHeaders().getContentType(), outputMessage);
}
private static Optional<Long> contentLength(Resource resource) {
// Don't try to determine contentLength on InputStreamResource - cannot be read afterwards...
// Note: custom InputStreamResource subclasses could provide a pre-calculated content length!
if (InputStreamResource.class != resource.getClass()) {
try {
return Optional.of(resource.contentLength());
}
catch (IOException ignored) {
}
}
return Optional.empty();
}
private static Optional<File> getFile(Resource resource) {
if (ResourceUtils2.hasFile(resource)) {
try {
return Optional.of(resource.getFile());
}
catch (IOException ignored) {
// should not happen
}
}
return Optional.empty();
}
}