org.springframework.http.codec.json.Jackson2JsonDecoder 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.codec.json;
import java.nio.charset.Charset;
import java.nio.charset.StandardCharsets;
import java.util.Arrays;
import java.util.Map;
import com.fasterxml.jackson.databind.ObjectMapper;
import org.reactivestreams.Publisher;
import reactor.core.publisher.Flux;
import org.springframework.core.ResolvableType;
import org.springframework.core.codec.StringDecoder;
import org.springframework.core.io.buffer.DataBuffer;
import org.springframework.core.io.buffer.DefaultDataBufferFactory;
import org.springframework.http.converter.json.Jackson2ObjectMapperBuilder;
import org.springframework.lang.Nullable;
import org.springframework.util.MimeType;
import org.springframework.util.MimeTypeUtils;
/**
* Decode a byte stream into JSON and convert to Object's with Jackson 2.x,
* leveraging non-blocking parsing.
*
* @author Sebastien Deleuze
* @author Rossen Stoyanchev
* @since 5.0
* @see Jackson2JsonEncoder
*/
public class Jackson2JsonDecoder extends AbstractJackson2Decoder {
private static final StringDecoder STRING_DECODER = StringDecoder.textPlainOnly(Arrays.asList(",", "\n"), false);
private static final ResolvableType STRING_TYPE = ResolvableType.forClass(String.class);
public Jackson2JsonDecoder() {
super(Jackson2ObjectMapperBuilder.json().build());
}
public Jackson2JsonDecoder(ObjectMapper mapper, MimeType... mimeTypes) {
super(mapper, mimeTypes);
}
@Override
protected Flux processInput(Publisher input, ResolvableType elementType,
@Nullable MimeType mimeType, @Nullable Map hints) {
Flux flux = Flux.from(input);
if (mimeType == null) {
return flux;
}
// Jackson asynchronous parser only supports UTF-8
Charset charset = mimeType.getCharset();
if (charset == null || StandardCharsets.UTF_8.equals(charset) || StandardCharsets.US_ASCII.equals(charset)) {
return flux;
}
// Potentially, the memory consumption of this conversion could be improved by using CharBuffers instead
// of allocating Strings, but that would require refactoring the buffer tokenization code from StringDecoder
MimeType textMimeType = new MimeType(MimeTypeUtils.TEXT_PLAIN, charset);
Flux decoded = STRING_DECODER.decode(input, STRING_TYPE, textMimeType, null);
return decoded.map(s -> DefaultDataBufferFactory.sharedInstance.wrap(s.getBytes(StandardCharsets.UTF_8)));
}
}