org.springframework.http.converter.protobuf.ProtobufHttpMessageConverter 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.protobuf;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.io.OutputStreamWriter;
import java.lang.reflect.Method;
import java.nio.charset.Charset;
import java.nio.charset.StandardCharsets;
import java.util.Arrays;
import java.util.Map;
import com.google.protobuf.CodedOutputStream;
import com.google.protobuf.ExtensionRegistry;
import com.google.protobuf.Message;
import com.google.protobuf.TextFormat;
import com.google.protobuf.util.JsonFormat;
import org.springframework.http.HttpInputMessage;
import org.springframework.http.HttpOutputMessage;
import org.springframework.http.MediaType;
import org.springframework.http.converter.AbstractHttpMessageConverter;
import org.springframework.http.converter.HttpMessageConversionException;
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.ClassUtils;
import org.springframework.util.ConcurrentReferenceHashMap;
import static org.springframework.http.MediaType.APPLICATION_JSON;
import static org.springframework.http.MediaType.TEXT_PLAIN;
/**
* An {@code HttpMessageConverter} that reads and writes
* {@link com.google.protobuf.Message com.google.protobuf.Messages} using
* Google Protocol Buffers.
*
* To generate {@code Message} Java classes, you need to install the {@code protoc} binary.
*
*
This converter supports by default {@code "application/x-protobuf"} and {@code "text/plain"}
* with the official {@code "com.google.protobuf:protobuf-java"} library.
* The {@code "application/json"} format is also supported with the {@code "com.google.protobuf:protobuf-java-util"}
* dependency. See {@link ProtobufJsonFormatHttpMessageConverter} for a configurable variant.
*
*
This converter requires Protobuf 3 or higher as of Spring Framework 6.1.
*
* @author Alex Antonov
* @author Brian Clozel
* @author Juergen Hoeller
* @author Sebastien Deleuze
* @since 4.1
* @see JsonFormat
* @see ProtobufJsonFormatHttpMessageConverter
*/
public class ProtobufHttpMessageConverter extends AbstractHttpMessageConverter {
/**
* The default charset used by the converter.
*/
public static final Charset DEFAULT_CHARSET = StandardCharsets.UTF_8;
/**
* The media-type for protobuf {@code application/x-protobuf}.
*/
public static final MediaType PROTOBUF = new MediaType("application", "x-protobuf", DEFAULT_CHARSET);
/**
* The HTTP header containing the protobuf schema.
*/
public static final String X_PROTOBUF_SCHEMA_HEADER = "X-Protobuf-Schema";
/**
* The HTTP header containing the protobuf message.
*/
public static final String X_PROTOBUF_MESSAGE_HEADER = "X-Protobuf-Message";
private static final boolean protobufJsonFormatPresent = ClassUtils.isPresent("com.google.protobuf.util.JsonFormat", ProtobufHttpMessageConverter.class.getClassLoader());
private static final Map, Method> methodCache = new ConcurrentReferenceHashMap<>();
final ExtensionRegistry extensionRegistry;
@Nullable
private final ProtobufFormatSupport protobufFormatSupport;
/**
* Construct a new {@code ProtobufHttpMessageConverter}.
*/
public ProtobufHttpMessageConverter() {
this(null, null);
}
/**
* Construct a new {@code ProtobufHttpMessageConverter} with a registry that specifies
* protocol message extensions.
* @param extensionRegistry the registry to populate
*/
public ProtobufHttpMessageConverter(ExtensionRegistry extensionRegistry) {
this(null, extensionRegistry);
}
ProtobufHttpMessageConverter(@Nullable ProtobufFormatSupport formatSupport,
@Nullable ExtensionRegistry extensionRegistry) {
if (formatSupport != null) {
this.protobufFormatSupport = formatSupport;
}
else if (protobufJsonFormatPresent) {
this.protobufFormatSupport = new ProtobufJavaUtilSupport(null, null);
}
else {
this.protobufFormatSupport = null;
}
setSupportedMediaTypes(Arrays.asList(this.protobufFormatSupport != null ?
this.protobufFormatSupport.supportedMediaTypes() : new MediaType[] {PROTOBUF, TEXT_PLAIN}));
this.extensionRegistry = (extensionRegistry == null ? ExtensionRegistry.newInstance() : extensionRegistry);
}
@Override
protected boolean supports(Class clazz) {
return Message.class.isAssignableFrom(clazz);
}
@Override
protected MediaType getDefaultContentType(Message message) {
return PROTOBUF;
}
@Override
protected Message readInternal(Class clazz, HttpInputMessage inputMessage)
throws IOException, HttpMessageNotReadableException {
MediaType contentType = inputMessage.getHeaders().getContentType();
if (contentType == null) {
contentType = PROTOBUF;
}
Charset charset = contentType.getCharset();
if (charset == null) {
charset = DEFAULT_CHARSET;
}
Message.Builder builder = getMessageBuilder(clazz);
if (PROTOBUF.isCompatibleWith(contentType)) {
builder.mergeFrom(inputMessage.getBody(), this.extensionRegistry);
}
else if (TEXT_PLAIN.isCompatibleWith(contentType)) {
InputStreamReader reader = new InputStreamReader(inputMessage.getBody(), charset);
TextFormat.merge(reader, this.extensionRegistry, builder);
}
else if (this.protobufFormatSupport != null) {
this.protobufFormatSupport.merge(
inputMessage.getBody(), charset, contentType, this.extensionRegistry, builder);
}
return builder.build();
}
/**
* Create a new {@code Message.Builder} instance for the given class.
* This method uses a ConcurrentReferenceHashMap for caching method lookups.
*/
private Message.Builder getMessageBuilder(Class clazz) {
try {
Method method = methodCache.get(clazz);
if (method == null) {
method = clazz.getMethod("newBuilder");
methodCache.put(clazz, method);
}
return (Message.Builder) method.invoke(clazz);
}
catch (Exception ex) {
throw new HttpMessageConversionException(
"Invalid Protobuf Message type: no invocable newBuilder() method on " + clazz, ex);
}
}
@Override
protected boolean canWrite(@Nullable MediaType mediaType) {
return (super.canWrite(mediaType) ||
(this.protobufFormatSupport != null && this.protobufFormatSupport.supportsWriteOnly(mediaType)));
}
@SuppressWarnings("deprecation")
@Override
protected void writeInternal(Message message, HttpOutputMessage outputMessage)
throws IOException, HttpMessageNotWritableException {
MediaType contentType = outputMessage.getHeaders().getContentType();
if (contentType == null) {
contentType = getDefaultContentType(message);
Assert.state(contentType != null, "No content type");
}
Charset charset = contentType.getCharset();
if (charset == null) {
charset = DEFAULT_CHARSET;
}
if (PROTOBUF.isCompatibleWith(contentType)) {
setProtoHeader(outputMessage, message);
CodedOutputStream codedOutputStream = CodedOutputStream.newInstance(outputMessage.getBody());
message.writeTo(codedOutputStream);
codedOutputStream.flush();
}
else if (TEXT_PLAIN.isCompatibleWith(contentType)) {
OutputStreamWriter outputStreamWriter = new OutputStreamWriter(outputMessage.getBody(), charset);
TextFormat.print(message, outputStreamWriter); // deprecated on Protobuf 3.9
outputStreamWriter.flush();
outputMessage.getBody().flush();
}
else if (this.protobufFormatSupport != null) {
this.protobufFormatSupport.print(message, outputMessage.getBody(), contentType, charset);
outputMessage.getBody().flush();
}
}
/**
* Set the "X-Protobuf-*" HTTP headers when responding with a message of
* content type "application/x-protobuf"
*
Note: outputMessage.getBody() should not have been called
* before because it writes HTTP headers (making them read only).
*/
private void setProtoHeader(HttpOutputMessage response, Message message) {
response.getHeaders().set(X_PROTOBUF_SCHEMA_HEADER, message.getDescriptorForType().getFile().getName());
response.getHeaders().set(X_PROTOBUF_MESSAGE_HEADER, message.getDescriptorForType().getFullName());
}
@Override
protected boolean supportsRepeatableWrites(Message message) {
return true;
}
/**
* Protobuf format support.
*/
interface ProtobufFormatSupport {
MediaType[] supportedMediaTypes();
boolean supportsWriteOnly(@Nullable MediaType mediaType);
void merge(InputStream input, Charset charset, MediaType contentType,
ExtensionRegistry extensionRegistry, Message.Builder builder)
throws IOException, HttpMessageConversionException;
void print(Message message, OutputStream output, MediaType contentType, Charset charset)
throws IOException, HttpMessageConversionException;
}
/**
* {@link ProtobufFormatSupport} implementation used when
* {@code com.google.protobuf.util.JsonFormat} is available.
*/
static class ProtobufJavaUtilSupport implements ProtobufFormatSupport {
private final JsonFormat.Parser parser;
private final JsonFormat.Printer printer;
public ProtobufJavaUtilSupport(@Nullable JsonFormat.Parser parser, @Nullable JsonFormat.Printer printer) {
this.parser = (parser != null ? parser : JsonFormat.parser());
this.printer = (printer != null ? printer : JsonFormat.printer());
}
@Override
public MediaType[] supportedMediaTypes() {
return new MediaType[] {PROTOBUF, TEXT_PLAIN, APPLICATION_JSON};
}
@Override
public boolean supportsWriteOnly(@Nullable MediaType mediaType) {
return false;
}
@Override
public void merge(InputStream input, Charset charset, MediaType contentType,
ExtensionRegistry extensionRegistry, Message.Builder builder)
throws IOException, HttpMessageConversionException {
if (contentType.isCompatibleWith(APPLICATION_JSON)) {
InputStreamReader reader = new InputStreamReader(input, charset);
this.parser.merge(reader, builder);
}
else {
throw new HttpMessageConversionException(
"protobuf-java-util does not support parsing " + contentType);
}
}
@Override
public void print(Message message, OutputStream output, MediaType contentType, Charset charset)
throws IOException, HttpMessageConversionException {
if (contentType.isCompatibleWith(APPLICATION_JSON)) {
OutputStreamWriter writer = new OutputStreamWriter(output, charset);
this.printer.appendTo(message, writer);
writer.flush();
}
else {
throw new HttpMessageConversionException(
"protobuf-java-util does not support printing " + contentType);
}
}
}
}