org.springframework.http.converter.BufferedImageHttpMessageConverter Maven / Gradle / Ivy
/*
* Copyright 2002-2022 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.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.util.ArrayList;
import java.util.Collections;
import java.util.Iterator;
import java.util.List;
import javax.imageio.IIOImage;
import javax.imageio.ImageIO;
import javax.imageio.ImageReadParam;
import javax.imageio.ImageReader;
import javax.imageio.ImageWriteParam;
import javax.imageio.ImageWriter;
import javax.imageio.stream.FileCacheImageInputStream;
import javax.imageio.stream.FileCacheImageOutputStream;
import javax.imageio.stream.ImageInputStream;
import javax.imageio.stream.ImageOutputStream;
import javax.imageio.stream.MemoryCacheImageInputStream;
import javax.imageio.stream.MemoryCacheImageOutputStream;
import org.springframework.http.HttpInputMessage;
import org.springframework.http.HttpOutputMessage;
import org.springframework.http.MediaType;
import org.springframework.http.StreamingHttpOutputMessage;
import org.springframework.lang.Nullable;
import org.springframework.util.Assert;
import org.springframework.util.StreamUtils;
import org.springframework.util.StringUtils;
/**
* Implementation of {@link HttpMessageConverter} that can read and write
* {@link BufferedImage BufferedImages}.
*
* By default, this converter can read all media types that are supported
* by the {@linkplain ImageIO#getReaderMIMETypes() registered image readers},
* and writes using the media type of the first available
* {@linkplain javax.imageio.ImageIO#getWriterMIMETypes() registered image writer}.
* The latter can be overridden by setting the
* {@link #setDefaultContentType defaultContentType} property.
*
*
If the {@link #setCacheDir cacheDir} property is set, this converter
* will cache image data.
*
*
The {@link #process(ImageReadParam)} and {@link #process(ImageWriteParam)}
* template methods allow subclasses to override Image I/O parameters.
*
* @author Arjen Poutsma
* @since 3.0
*/
public class BufferedImageHttpMessageConverter implements HttpMessageConverter {
private final List readableMediaTypes = new ArrayList<>();
@Nullable
private MediaType defaultContentType;
@Nullable
private File cacheDir;
public BufferedImageHttpMessageConverter() {
String[] readerMediaTypes = ImageIO.getReaderMIMETypes();
for (String mediaType : readerMediaTypes) {
if (StringUtils.hasText(mediaType)) {
this.readableMediaTypes.add(MediaType.parseMediaType(mediaType));
}
}
String[] writerMediaTypes = ImageIO.getWriterMIMETypes();
for (String mediaType : writerMediaTypes) {
if (StringUtils.hasText(mediaType)) {
this.defaultContentType = MediaType.parseMediaType(mediaType);
break;
}
}
}
/**
* Sets the default {@code Content-Type} to be used for writing.
* @throws IllegalArgumentException if the given content type is not supported by the Java Image I/O API
*/
public void setDefaultContentType(@Nullable MediaType defaultContentType) {
if (defaultContentType != null) {
Iterator imageWriters = ImageIO.getImageWritersByMIMEType(defaultContentType.toString());
if (!imageWriters.hasNext()) {
throw new IllegalArgumentException(
"Content-Type [" + defaultContentType + "] is not supported by the Java Image I/O API");
}
}
this.defaultContentType = defaultContentType;
}
/**
* Returns the default {@code Content-Type} to be used for writing.
* Called when {@link #write} is invoked without a specified content type parameter.
*/
@Nullable
public MediaType getDefaultContentType() {
return this.defaultContentType;
}
/**
* Sets the cache directory. If this property is set to an existing directory,
* this converter will cache image data.
*/
public void setCacheDir(File cacheDir) {
Assert.notNull(cacheDir, "'cacheDir' must not be null");
Assert.isTrue(cacheDir.isDirectory(), () -> "'cacheDir' is not a directory: " + cacheDir);
this.cacheDir = cacheDir;
}
@Override
public boolean canRead(Class clazz, @Nullable MediaType mediaType) {
return (BufferedImage.class == clazz && isReadable(mediaType));
}
private boolean isReadable(@Nullable MediaType mediaType) {
if (mediaType == null) {
return true;
}
Iterator imageReaders = ImageIO.getImageReadersByMIMEType(mediaType.toString());
return imageReaders.hasNext();
}
@Override
public boolean canWrite(Class clazz, @Nullable MediaType mediaType) {
return (BufferedImage.class == clazz && isWritable(mediaType));
}
private boolean isWritable(@Nullable MediaType mediaType) {
if (mediaType == null || MediaType.ALL.equalsTypeAndSubtype(mediaType)) {
return true;
}
Iterator imageWriters = ImageIO.getImageWritersByMIMEType(mediaType.toString());
return imageWriters.hasNext();
}
@Override
public List getSupportedMediaTypes() {
return Collections.unmodifiableList(this.readableMediaTypes);
}
@Override
public BufferedImage read(@Nullable Class clazz, HttpInputMessage inputMessage)
throws IOException, HttpMessageNotReadableException {
ImageInputStream imageInputStream = null;
ImageReader imageReader = null;
// We cannot use try-with-resources here for the ImageInputStream, since we have
// custom handling of the close() method in a finally-block.
try {
imageInputStream = createImageInputStream(inputMessage.getBody());
MediaType contentType = inputMessage.getHeaders().getContentType();
if (contentType == null) {
throw new HttpMessageNotReadableException("No Content-Type header", inputMessage);
}
Iterator imageReaders = ImageIO.getImageReadersByMIMEType(contentType.toString());
if (imageReaders.hasNext()) {
imageReader = imageReaders.next();
ImageReadParam irp = imageReader.getDefaultReadParam();
process(irp);
imageReader.setInput(imageInputStream, true);
return imageReader.read(0, irp);
}
else {
throw new HttpMessageNotReadableException(
"Could not find javax.imageio.ImageReader for Content-Type [" + contentType + "]",
inputMessage);
}
}
finally {
if (imageReader != null) {
imageReader.dispose();
}
if (imageInputStream != null) {
try {
imageInputStream.close();
}
catch (IOException ex) {
// ignore
}
}
}
}
private ImageInputStream createImageInputStream(InputStream is) throws IOException {
is = StreamUtils.nonClosing(is);
if (this.cacheDir != null) {
return new FileCacheImageInputStream(is, this.cacheDir);
}
else {
return new MemoryCacheImageInputStream(is);
}
}
@Override
public void write(final BufferedImage image, @Nullable final MediaType contentType,
final HttpOutputMessage outputMessage)
throws IOException, HttpMessageNotWritableException {
final MediaType selectedContentType = getContentType(contentType);
outputMessage.getHeaders().setContentType(selectedContentType);
if (outputMessage instanceof StreamingHttpOutputMessage) {
StreamingHttpOutputMessage streamingOutputMessage = (StreamingHttpOutputMessage) outputMessage;
streamingOutputMessage.setBody(outputStream -> writeInternal(image, selectedContentType, outputStream));
}
else {
writeInternal(image, selectedContentType, outputMessage.getBody());
}
}
private MediaType getContentType(@Nullable MediaType contentType) {
if (contentType == null || contentType.isWildcardType() || contentType.isWildcardSubtype()) {
contentType = getDefaultContentType();
}
Assert.notNull(contentType, "Could not select Content-Type. " +
"Please specify one through the 'defaultContentType' property.");
return contentType;
}
private void writeInternal(BufferedImage image, MediaType contentType, OutputStream body)
throws IOException, HttpMessageNotWritableException {
ImageOutputStream imageOutputStream = null;
ImageWriter imageWriter = null;
try {
Iterator imageWriters = ImageIO.getImageWritersByMIMEType(contentType.toString());
if (imageWriters.hasNext()) {
imageWriter = imageWriters.next();
ImageWriteParam iwp = imageWriter.getDefaultWriteParam();
process(iwp);
imageOutputStream = createImageOutputStream(body);
imageWriter.setOutput(imageOutputStream);
imageWriter.write(null, new IIOImage(image, null, null), iwp);
}
else {
throw new HttpMessageNotWritableException(
"Could not find javax.imageio.ImageWriter for Content-Type [" + contentType + "]");
}
}
finally {
if (imageWriter != null) {
imageWriter.dispose();
}
if (imageOutputStream != null) {
try {
imageOutputStream.close();
}
catch (IOException ex) {
// ignore
}
}
}
}
private ImageOutputStream createImageOutputStream(OutputStream os) throws IOException {
if (this.cacheDir != null) {
return new FileCacheImageOutputStream(os, this.cacheDir);
}
else {
return new MemoryCacheImageOutputStream(os);
}
}
/**
* Template method that allows for manipulating the {@link ImageReadParam}
* before it is used to read an image.
* The default implementation is empty.
*/
protected void process(ImageReadParam irp) {
}
/**
* Template method that allows for manipulating the {@link ImageWriteParam}
* before it is used to write an image.
*
The default implementation is empty.
*/
protected void process(ImageWriteParam iwp) {
}
}