org.springframework.http.converter.ResourceHttpMessageConverter Maven / Gradle / Ivy
/*
* Copyright 2002-2023 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
*
* https://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;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import org.springframework.core.io.ByteArrayResource;
import org.springframework.core.io.InputStreamResource;
import org.springframework.core.io.Resource;
import org.springframework.http.HttpInputMessage;
import org.springframework.http.HttpOutputMessage;
import org.springframework.http.MediaType;
import org.springframework.http.MediaTypeFactory;
import org.springframework.lang.Nullable;
import org.springframework.util.StreamUtils;
/**
* Implementation of {@link HttpMessageConverter} that can read/write {@link Resource Resources}
* and supports byte range requests.
*
* By default, this converter can read all media types. The {@link MediaTypeFactory} is used
* to determine the {@code Content-Type} of written resources.
*
* @author Arjen Poutsma
* @author Juergen Hoeller
* @author Kazuki Shimizu
* @since 3.0.2
*/
public class ResourceHttpMessageConverter extends AbstractHttpMessageConverter {
private final boolean supportsReadStreaming;
/**
* Create a new instance of the {@code ResourceHttpMessageConverter}
* that supports read streaming, i.e. can convert an
* {@code HttpInputMessage} to {@code InputStreamResource}.
*/
public ResourceHttpMessageConverter() {
super(MediaType.ALL);
this.supportsReadStreaming = true;
}
/**
* Create a new instance of the {@code ResourceHttpMessageConverter}.
* @param supportsReadStreaming whether the converter should support
* read streaming, i.e. convert to {@code InputStreamResource}
* @since 5.0
*/
public ResourceHttpMessageConverter(boolean supportsReadStreaming) {
super(MediaType.ALL);
this.supportsReadStreaming = supportsReadStreaming;
}
@Override
protected boolean supports(Class clazz) {
return Resource.class.isAssignableFrom(clazz);
}
@Override
protected Resource readInternal(Class clazz, HttpInputMessage inputMessage)
throws IOException, HttpMessageNotReadableException {
if (this.supportsReadStreaming && InputStreamResource.class == clazz) {
return new InputStreamResource(inputMessage.getBody()) {
@Override
public String getFilename() {
return inputMessage.getHeaders().getContentDisposition().getFilename();
}
@Override
public long contentLength() throws IOException {
long length = inputMessage.getHeaders().getContentLength();
return (length != -1 ? length : super.contentLength());
}
};
}
else if (Resource.class == clazz || ByteArrayResource.class.isAssignableFrom(clazz)) {
byte[] body = StreamUtils.copyToByteArray(inputMessage.getBody());
return new ByteArrayResource(body) {
@Override
@Nullable
public String getFilename() {
return inputMessage.getHeaders().getContentDisposition().getFilename();
}
};
}
else {
throw new HttpMessageNotReadableException("Unsupported resource class: " + clazz, inputMessage);
}
}
@Override
protected MediaType getDefaultContentType(Resource resource) {
return MediaTypeFactory.getMediaType(resource).orElse(MediaType.APPLICATION_OCTET_STREAM);
}
@Override
protected Long getContentLength(Resource resource, @Nullable MediaType contentType) throws IOException {
// 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()) {
return null;
}
long contentLength = resource.contentLength();
return (contentLength < 0 ? null : contentLength);
}
/**
* Adds the default headers for the given resource to the given message.
* @since 6.0
*/
public void addDefaultHeaders(HttpOutputMessage message, Resource resource, @Nullable MediaType contentType) throws IOException {
addDefaultHeaders(message.getHeaders(), resource, contentType);
}
@Override
protected void writeInternal(Resource resource, HttpOutputMessage outputMessage)
throws IOException, HttpMessageNotWritableException {
writeContent(resource, outputMessage);
}
protected void writeContent(Resource resource, HttpOutputMessage outputMessage)
throws IOException, HttpMessageNotWritableException {
// We cannot use try-with-resources here for the InputStream, since we have
// custom handling of the close() method in a finally-block.
try {
InputStream in = resource.getInputStream();
try {
OutputStream out = outputMessage.getBody();
in.transferTo(out);
out.flush();
}
catch (NullPointerException ex) {
// ignore, see SPR-13620
}
finally {
try {
in.close();
}
catch (Throwable ex) {
// ignore, see SPR-12999
}
}
}
catch (FileNotFoundException ex) {
// ignore, see SPR-12999
}
}
@Override
protected boolean supportsRepeatableWrites(Resource resource) {
return !(resource instanceof InputStreamResource);
}
}