com.clarifai.channel.JsonMarshaller Maven / Gradle / Ivy
package com.clarifai.channel;
/*
* Copyright 2018 The gRPC 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
*
* http://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.
*/
import com.clarifai.grpc.api.Concept;
import com.google.protobuf.Descriptors;
import com.google.protobuf.InvalidProtocolBufferException;
import com.google.protobuf.Message;
import com.google.protobuf.Message.Builder;
import com.google.protobuf.util.JsonFormat;
import com.google.protobuf.util.JsonFormat.Parser;
import com.google.protobuf.util.JsonFormat.Printer;
import io.grpc.MethodDescriptor.Marshaller;
import io.grpc.Status;
import java.io.*;
import java.nio.charset.Charset;
import java.util.HashSet;
/**
* A {@link Marshaller} for JSON. This marshals in the Protobuf 3 format described here:
* https://developers.google.com/protocol-buffers/docs/proto3#json
*/
public final class JsonMarshaller {
private JsonMarshaller() {}
/**
* Create a {@code Marshaller} for json protos of the same type as {@code defaultInstance}.
*
* This is an unstable API and has not been optimized yet for performance.
*/
public static Marshaller jsonMarshaller(final T defaultInstance) {
final Parser parser = JsonFormat.parser()
.ignoringUnknownFields();
Descriptors.FieldDescriptor value =
Concept.newBuilder().getDescriptorForType().findFieldByName("value");
HashSet defaultValueFields = new HashSet<>();
defaultValueFields.add(value);
Printer printer = JsonFormat.printer()
.preservingProtoFieldNames()
.includingDefaultValueFields(defaultValueFields);
return jsonMarshaller(defaultInstance, parser, printer);
}
/**
* Create a {@code Marshaller} for json protos of the same type as {@code defaultInstance}.
*
* This is an unstable API and has not been optimized yet for performance.
*/
public static Marshaller jsonMarshaller(
final T defaultInstance, final Parser parser, final Printer printer) {
final Charset charset = Charset.forName("UTF-8");
return new Marshaller() {
@Override
public InputStream stream(T value) {
try {
return new ByteArrayInputStream(printer.print(value).getBytes(charset));
} catch (InvalidProtocolBufferException e) {
throw Status.INTERNAL
.withCause(e)
.withDescription("Unable to print json proto")
.asRuntimeException();
}
}
@SuppressWarnings("unchecked")
@Override
public T parse(InputStream stream) {
Builder builder = defaultInstance.newBuilderForType();
Reader reader = new InputStreamReader(stream, charset);
T proto;
try {
parser.merge(reader, builder);
proto = (T) builder.build();
reader.close();
} catch (InvalidProtocolBufferException e) {
throw Status.INTERNAL.withDescription("Invalid protobuf byte sequence")
.withCause(e).asRuntimeException();
} catch (IOException e) {
// Same for now, might be unavailable
throw Status.INTERNAL.withDescription("Invalid protobuf byte sequence")
.withCause(e).asRuntimeException();
}
return proto;
}
};
}
}