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/*
 * 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.json;

import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.io.Reader;
import java.lang.reflect.Type;
import java.nio.charset.Charset;
import java.nio.charset.StandardCharsets;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collections;
import java.util.LinkedHashMap;
import java.util.List;
import java.util.Map;
import java.util.concurrent.atomic.AtomicReference;
import java.util.function.Consumer;

import com.fasterxml.jackson.core.JsonEncoding;
import com.fasterxml.jackson.core.JsonGenerator;
import com.fasterxml.jackson.core.JsonProcessingException;
import com.fasterxml.jackson.core.PrettyPrinter;
import com.fasterxml.jackson.core.util.DefaultIndenter;
import com.fasterxml.jackson.core.util.DefaultPrettyPrinter;
import com.fasterxml.jackson.databind.JavaType;
import com.fasterxml.jackson.databind.JsonMappingException;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.databind.ObjectReader;
import com.fasterxml.jackson.databind.ObjectWriter;
import com.fasterxml.jackson.databind.SerializationConfig;
import com.fasterxml.jackson.databind.SerializationFeature;
import com.fasterxml.jackson.databind.exc.InvalidDefinitionException;
import com.fasterxml.jackson.databind.ser.FilterProvider;

import org.springframework.core.GenericTypeResolver;
import org.springframework.http.HttpInputMessage;
import org.springframework.http.HttpOutputMessage;
import org.springframework.http.MediaType;
import org.springframework.http.ProblemDetail;
import org.springframework.http.converter.AbstractGenericHttpMessageConverter;
import org.springframework.http.converter.HttpMessageConversionException;
import org.springframework.http.converter.HttpMessageConverter;
import org.springframework.http.converter.HttpMessageNotReadableException;
import org.springframework.http.converter.HttpMessageNotWritableException;
import org.springframework.lang.Nullable;
import org.springframework.util.Assert;
import org.springframework.util.CollectionUtils;
import org.springframework.util.StreamUtils;
import org.springframework.util.TypeUtils;

/**
 * Abstract base class for Jackson based and content type independent
 * {@link HttpMessageConverter} implementations.
 *
 * @author Arjen Poutsma
 * @author Keith Donald
 * @author Rossen Stoyanchev
 * @author Juergen Hoeller
 * @author Sebastien Deleuze
 * @author Sam Brannen
 * @since 4.1
 * @see MappingJackson2HttpMessageConverter
 */
public abstract class AbstractJackson2HttpMessageConverter extends AbstractGenericHttpMessageConverter {

	private static final Map ENCODINGS;

	static {
		ENCODINGS = CollectionUtils.newHashMap(JsonEncoding.values().length);
		for (JsonEncoding encoding : JsonEncoding.values()) {
			ENCODINGS.put(encoding.getJavaName(), encoding);
		}
		ENCODINGS.put("US-ASCII", JsonEncoding.UTF8);
	}


	private List problemDetailMediaTypes = Collections.singletonList(MediaType.APPLICATION_PROBLEM_JSON);

	protected ObjectMapper defaultObjectMapper;

	@Nullable
	private Map, Map> objectMapperRegistrations;

	@Nullable
	private Boolean prettyPrint;

	@Nullable
	private final PrettyPrinter ssePrettyPrinter;


	protected AbstractJackson2HttpMessageConverter(ObjectMapper objectMapper) {
		this.defaultObjectMapper = objectMapper;
		DefaultPrettyPrinter prettyPrinter = new DefaultPrettyPrinter();
		prettyPrinter.indentObjectsWith(new DefaultIndenter("  ", "\ndata:"));
		this.ssePrettyPrinter = prettyPrinter;
	}

	protected AbstractJackson2HttpMessageConverter(ObjectMapper objectMapper, MediaType supportedMediaType) {
		this(objectMapper);
		setSupportedMediaTypes(Collections.singletonList(supportedMediaType));
	}

	protected AbstractJackson2HttpMessageConverter(ObjectMapper objectMapper, MediaType... supportedMediaTypes) {
		this(objectMapper);
		setSupportedMediaTypes(Arrays.asList(supportedMediaTypes));
	}


	@Override
	public void setSupportedMediaTypes(List supportedMediaTypes) {
		this.problemDetailMediaTypes = initProblemDetailMediaTypes(supportedMediaTypes);
		super.setSupportedMediaTypes(supportedMediaTypes);
	}

	private List initProblemDetailMediaTypes(List supportedMediaTypes) {
		List mediaTypes = new ArrayList<>();
		mediaTypes.add(MediaType.APPLICATION_PROBLEM_JSON);
		mediaTypes.addAll(supportedMediaTypes);
		return Collections.unmodifiableList(mediaTypes);
	}

	/**
	 * Configure the main {@code ObjectMapper} to use for Object conversion.
	 * If not set, a default {@link ObjectMapper} instance is created.
	 * 

Setting a custom-configured {@code ObjectMapper} is one way to take * further control of the JSON serialization process. For example, an extended * {@link com.fasterxml.jackson.databind.ser.SerializerFactory} * can be configured that provides custom serializers for specific types. * Another option for refining the serialization process is to use Jackson's * provided annotations on the types to be serialized, in which case a * custom-configured ObjectMapper is unnecessary. * @see #registerObjectMappersForType(Class, Consumer) */ public void setObjectMapper(ObjectMapper objectMapper) { Assert.notNull(objectMapper, "ObjectMapper must not be null"); this.defaultObjectMapper = objectMapper; configurePrettyPrint(); } /** * Return the main {@code ObjectMapper} in use. */ public ObjectMapper getObjectMapper() { return this.defaultObjectMapper; } /** * Configure the {@link ObjectMapper} instances to use for the given * {@link Class}. This is useful when you want to deviate from the * {@link #getObjectMapper() default} ObjectMapper or have the * {@code ObjectMapper} vary by {@code MediaType}. *

Note: Use of this method effectively turns off use of * the default {@link #getObjectMapper() ObjectMapper} and * {@link #setSupportedMediaTypes(List) supportedMediaTypes} for the given * class. Therefore it is important for the mappings configured here to * {@link MediaType#includes(MediaType) include} every MediaType that must * be supported for the given class. * @param clazz the type of Object to register ObjectMapper instances for * @param registrar a consumer to populate or otherwise update the * MediaType-to-ObjectMapper associations for the given Class * @since 5.3.4 */ public void registerObjectMappersForType(Class clazz, Consumer> registrar) { if (this.objectMapperRegistrations == null) { this.objectMapperRegistrations = new LinkedHashMap<>(); } Map registrations = this.objectMapperRegistrations.computeIfAbsent(clazz, c -> new LinkedHashMap<>()); registrar.accept(registrations); } /** * Return ObjectMapper registrations for the given class, if any. * @param clazz the class to look up for registrations for * @return a map with registered MediaType-to-ObjectMapper registrations, * or empty if in case of no registrations for the given class. * @since 5.3.4 */ @Nullable public Map getObjectMappersForType(Class clazz) { for (Map.Entry, Map> entry : getObjectMapperRegistrations().entrySet()) { if (entry.getKey().isAssignableFrom(clazz)) { return entry.getValue(); } } return Collections.emptyMap(); } @Override public List getSupportedMediaTypes(Class clazz) { List result = null; for (Map.Entry, Map> entry : getObjectMapperRegistrations().entrySet()) { if (entry.getKey().isAssignableFrom(clazz)) { result = (result != null ? result : new ArrayList<>(entry.getValue().size())); result.addAll(entry.getValue().keySet()); } } if (!CollectionUtils.isEmpty(result)) { return result; } return (ProblemDetail.class.isAssignableFrom(clazz) ? this.problemDetailMediaTypes : getSupportedMediaTypes()); } private Map, Map> getObjectMapperRegistrations() { return (this.objectMapperRegistrations != null ? this.objectMapperRegistrations : Collections.emptyMap()); } /** * Whether to use the {@link DefaultPrettyPrinter} when writing JSON. * This is a shortcut for setting up an {@code ObjectMapper} as follows: *

	 * ObjectMapper mapper = new ObjectMapper();
	 * mapper.configure(SerializationFeature.INDENT_OUTPUT, true);
	 * converter.setObjectMapper(mapper);
	 * 
*/ public void setPrettyPrint(boolean prettyPrint) { this.prettyPrint = prettyPrint; configurePrettyPrint(); } private void configurePrettyPrint() { if (this.prettyPrint != null) { this.defaultObjectMapper.configure(SerializationFeature.INDENT_OUTPUT, this.prettyPrint); } } @Override public boolean canRead(Class clazz, @Nullable MediaType mediaType) { return canRead(clazz, null, mediaType); } @Override public boolean canRead(Type type, @Nullable Class contextClass, @Nullable MediaType mediaType) { if (!canRead(mediaType)) { return false; } JavaType javaType = getJavaType(type, contextClass); ObjectMapper objectMapper = selectObjectMapper(javaType.getRawClass(), mediaType); if (objectMapper == null) { return false; } AtomicReference causeRef = new AtomicReference<>(); if (objectMapper.canDeserialize(javaType, causeRef)) { return true; } logWarningIfNecessary(javaType, causeRef.get()); return false; } @Override public boolean canWrite(Class clazz, @Nullable MediaType mediaType) { if (!canWrite(mediaType)) { return false; } if (mediaType != null && mediaType.getCharset() != null) { Charset charset = mediaType.getCharset(); if (!ENCODINGS.containsKey(charset.name())) { return false; } } ObjectMapper objectMapper = selectObjectMapper(clazz, mediaType); if (objectMapper == null) { return false; } AtomicReference causeRef = new AtomicReference<>(); if (objectMapper.canSerialize(clazz, causeRef)) { return true; } logWarningIfNecessary(clazz, causeRef.get()); return false; } /** * Select an ObjectMapper to use, either the main ObjectMapper or another * if the handling for the given Class has been customized through * {@link #registerObjectMappersForType(Class, Consumer)}. */ @Nullable private ObjectMapper selectObjectMapper(Class targetType, @Nullable MediaType targetMediaType) { if (targetMediaType == null || CollectionUtils.isEmpty(this.objectMapperRegistrations)) { return this.defaultObjectMapper; } for (Map.Entry, Map> typeEntry : getObjectMapperRegistrations().entrySet()) { if (typeEntry.getKey().isAssignableFrom(targetType)) { for (Map.Entry objectMapperEntry : typeEntry.getValue().entrySet()) { if (objectMapperEntry.getKey().includes(targetMediaType)) { return objectMapperEntry.getValue(); } } // No matching registrations return null; } } // No registrations return this.defaultObjectMapper; } /** * Determine whether to log the given exception coming from a * {@link ObjectMapper#canDeserialize} / {@link ObjectMapper#canSerialize} check. * @param type the class that Jackson tested for (de-)serializability * @param cause the Jackson-thrown exception to evaluate * (typically a {@link JsonMappingException}) * @since 4.3 */ protected void logWarningIfNecessary(Type type, @Nullable Throwable cause) { if (cause == null) { return; } // Do not log warning for serializer not found (note: different message wording on Jackson 2.9) boolean debugLevel = (cause instanceof JsonMappingException && cause.getMessage().startsWith("Cannot find")); if (debugLevel ? logger.isDebugEnabled() : logger.isWarnEnabled()) { String msg = "Failed to evaluate Jackson " + (type instanceof JavaType ? "de" : "") + "serialization for type [" + type + "]"; if (debugLevel) { logger.debug(msg, cause); } else if (logger.isDebugEnabled()) { logger.warn(msg, cause); } else { logger.warn(msg + ": " + cause); } } } @Override public Object read(Type type, @Nullable Class contextClass, HttpInputMessage inputMessage) throws IOException, HttpMessageNotReadableException { JavaType javaType = getJavaType(type, contextClass); return readJavaType(javaType, inputMessage); } @Override protected Object readInternal(Class clazz, HttpInputMessage inputMessage) throws IOException, HttpMessageNotReadableException { JavaType javaType = getJavaType(clazz, null); return readJavaType(javaType, inputMessage); } private Object readJavaType(JavaType javaType, HttpInputMessage inputMessage) throws IOException { MediaType contentType = inputMessage.getHeaders().getContentType(); Charset charset = getCharset(contentType); ObjectMapper objectMapper = selectObjectMapper(javaType.getRawClass(), contentType); Assert.state(objectMapper != null, () -> "No ObjectMapper for " + javaType); boolean isUnicode = ENCODINGS.containsKey(charset.name()) || "UTF-16".equals(charset.name()) || "UTF-32".equals(charset.name()); try { InputStream inputStream = StreamUtils.nonClosing(inputMessage.getBody()); if (inputMessage instanceof MappingJacksonInputMessage mappingJacksonInputMessage) { Class deserializationView = mappingJacksonInputMessage.getDeserializationView(); if (deserializationView != null) { ObjectReader objectReader = objectMapper.readerWithView(deserializationView).forType(javaType); objectReader = customizeReader(objectReader, javaType); if (isUnicode) { return objectReader.readValue(inputStream); } else { Reader reader = new InputStreamReader(inputStream, charset); return objectReader.readValue(reader); } } } ObjectReader objectReader = objectMapper.reader().forType(javaType); objectReader = customizeReader(objectReader, javaType); if (isUnicode) { return objectReader.readValue(inputStream); } else { Reader reader = new InputStreamReader(inputStream, charset); return objectReader.readValue(reader); } } catch (InvalidDefinitionException ex) { throw new HttpMessageConversionException("Type definition error: " + ex.getType(), ex); } catch (JsonProcessingException ex) { throw new HttpMessageNotReadableException("JSON parse error: " + ex.getOriginalMessage(), ex, inputMessage); } } /** * Subclasses can use this method to customize {@link ObjectReader} used * for reading values. * @param reader the reader instance to customize * @param javaType the target type of element values to read to * @return the customized {@link ObjectReader} * @since 6.0 */ protected ObjectReader customizeReader(ObjectReader reader, JavaType javaType) { return reader; } /** * Determine the charset to use for JSON input. *

By default this is either the charset from the input {@code MediaType} * or otherwise falling back on {@code UTF-8}. Can be overridden in subclasses. * @param contentType the content type of the HTTP input message * @return the charset to use * @since 5.1.18 */ protected Charset getCharset(@Nullable MediaType contentType) { if (contentType != null && contentType.getCharset() != null) { return contentType.getCharset(); } else { return StandardCharsets.UTF_8; } } @Override protected void writeInternal(Object object, @Nullable Type type, HttpOutputMessage outputMessage) throws IOException, HttpMessageNotWritableException { MediaType contentType = outputMessage.getHeaders().getContentType(); JsonEncoding encoding = getJsonEncoding(contentType); Class clazz = (object instanceof MappingJacksonValue mappingJacksonValue ? mappingJacksonValue.getValue().getClass() : object.getClass()); ObjectMapper objectMapper = selectObjectMapper(clazz, contentType); Assert.state(objectMapper != null, () -> "No ObjectMapper for " + clazz.getName()); OutputStream outputStream = StreamUtils.nonClosing(outputMessage.getBody()); try (JsonGenerator generator = objectMapper.getFactory().createGenerator(outputStream, encoding)) { writePrefix(generator, object); Object value = object; Class serializationView = null; FilterProvider filters = null; JavaType javaType = null; if (object instanceof MappingJacksonValue mappingJacksonValue) { value = mappingJacksonValue.getValue(); serializationView = mappingJacksonValue.getSerializationView(); filters = mappingJacksonValue.getFilters(); } if (type != null && TypeUtils.isAssignable(type, value.getClass())) { javaType = getJavaType(type, null); } ObjectWriter objectWriter = (serializationView != null ? objectMapper.writerWithView(serializationView) : objectMapper.writer()); if (filters != null) { objectWriter = objectWriter.with(filters); } if (javaType != null && javaType.isContainerType()) { objectWriter = objectWriter.forType(javaType); } SerializationConfig config = objectWriter.getConfig(); if (contentType != null && contentType.isCompatibleWith(MediaType.TEXT_EVENT_STREAM) && config.isEnabled(SerializationFeature.INDENT_OUTPUT)) { objectWriter = objectWriter.with(this.ssePrettyPrinter); } objectWriter = customizeWriter(objectWriter, javaType, contentType); objectWriter.writeValue(generator, value); writeSuffix(generator, object); generator.flush(); } catch (InvalidDefinitionException ex) { throw new HttpMessageConversionException("Type definition error: " + ex.getType(), ex); } catch (JsonProcessingException ex) { throw new HttpMessageNotWritableException("Could not write JSON: " + ex.getOriginalMessage(), ex); } } /** * Subclasses can use this method to customize {@link ObjectWriter} used * for writing values. * @param writer the writer instance to customize * @param javaType the type of element values to write * @param contentType the selected media type * @return the customized {@link ObjectWriter} * @since 6.0 */ protected ObjectWriter customizeWriter( ObjectWriter writer, @Nullable JavaType javaType, @Nullable MediaType contentType) { return writer; } /** * Write a prefix before the main content. * @param generator the generator to use for writing content. * @param object the object to write to the output message. */ protected void writePrefix(JsonGenerator generator, Object object) throws IOException { } /** * Write a suffix after the main content. * @param generator the generator to use for writing content. * @param object the object to write to the output message. */ protected void writeSuffix(JsonGenerator generator, Object object) throws IOException { } /** * Return the Jackson {@link JavaType} for the specified type and context class. * @param type the generic type to return the Jackson JavaType for * @param contextClass a context class for the target type, for example a class * in which the target type appears in a method signature (can be {@code null}) * @return the Jackson JavaType */ protected JavaType getJavaType(Type type, @Nullable Class contextClass) { return this.defaultObjectMapper.constructType(GenericTypeResolver.resolveType(type, contextClass)); } /** * Determine the JSON encoding to use for the given content type. * @param contentType the media type as requested by the caller * @return the JSON encoding to use (never {@code null}) */ protected JsonEncoding getJsonEncoding(@Nullable MediaType contentType) { if (contentType != null && contentType.getCharset() != null) { Charset charset = contentType.getCharset(); JsonEncoding encoding = ENCODINGS.get(charset.name()); if (encoding != null) { return encoding; } } return JsonEncoding.UTF8; } @Override @Nullable protected MediaType getDefaultContentType(Object object) throws IOException { if (object instanceof MappingJacksonValue mappingJacksonValue) { object = mappingJacksonValue.getValue(); } return super.getDefaultContentType(object); } @Override protected Long getContentLength(Object object, @Nullable MediaType contentType) throws IOException { if (object instanceof MappingJacksonValue mappingJacksonValue) { object = mappingJacksonValue.getValue(); } return super.getContentLength(object, contentType); } }