io.grpc.protobuf.ProtoUtils Maven / Gradle / Ivy
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*
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package io.grpc.protobuf;
import com.google.protobuf.InvalidProtocolBufferException;
import com.google.protobuf.Message;
import com.google.protobuf.MessageLite;
import com.google.protobuf.Parser;
import io.grpc.Metadata;
import io.grpc.MethodDescriptor.Marshaller;
import io.grpc.Status;
import java.io.InputStream;
/**
* Utility methods for using protobuf with grpc.
*/
public class ProtoUtils {
/** Adapt a {@code Parser} to a {@code Marshaller}. */
public static Marshaller marshaller(final Parser parser) {
return new Marshaller() {
@Override
public InputStream stream(T value) {
return new ProtoInputStream(value, parser);
}
@Override
public T parse(InputStream stream) {
if (stream instanceof ProtoInputStream) {
ProtoInputStream protoStream = (ProtoInputStream) stream;
// Optimization for in-memory transport. Returning provided object is safe since protobufs
// are immutable.
//
// However, we can't assume the types match, so we have to verify the parser matches.
// Today the parser is always the same for a given proto, but that isn't guaranteed. Even
// if not, using the same MethodDescriptor would ensure the parser matches and permit us
// to enable this optimization.
if (protoStream.parser() == parser) {
@SuppressWarnings("unchecked")
T message = (T) ((ProtoInputStream) stream).message();
return message;
}
}
try {
return parser.parseFrom(stream);
} catch (InvalidProtocolBufferException ipbe) {
throw Status.INTERNAL.withDescription("Invalid protobuf byte sequence")
.withCause(ipbe).asRuntimeException();
}
}
};
}
/**
* Produce a metadata key for a generated protobuf type.
*/
public static Metadata.Key keyForProto(final T instance) {
return Metadata.Key.of(
instance.getDescriptorForType().getFullName() + Metadata.BINARY_HEADER_SUFFIX,
new Metadata.BinaryMarshaller() {
@Override
public byte[] toBytes(T value) {
return value.toByteArray();
}
@Override
@SuppressWarnings("unchecked")
public T parseBytes(byte[] serialized) {
try {
return (T) instance.getParserForType().parseFrom(serialized);
} catch (InvalidProtocolBufferException ipbe) {
throw new IllegalArgumentException(ipbe);
}
}
});
}
private ProtoUtils() {
}
}