package com.tinkerpop.gremlin.server.handler;
import com.tinkerpop.gremlin.driver.MessageSerializer;
import com.tinkerpop.gremlin.driver.message.RequestMessage;
import com.tinkerpop.gremlin.driver.ser.SerializationException;
import com.tinkerpop.gremlin.driver.ser.Serializers;
import io.netty.buffer.ByteBuf;
import io.netty.channel.ChannelHandlerContext;
import io.netty.handler.codec.ByteToMessageDecoder;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import java.nio.charset.Charset;
import java.util.List;
import java.util.Map;
/**
* @author Stephen Mallette (http://stephen.genoprime.com)
*/
public class NioGremlinBinaryRequestDecoder extends ByteToMessageDecoder {
private static final Logger logger = LoggerFactory.getLogger(WsGremlinBinaryRequestDecoder.class);
private static final Charset UTF8 = Charset.forName("UTF-8");
private final Map<String, MessageSerializer> serializers;
public NioGremlinBinaryRequestDecoder(final Map<String, MessageSerializer> serializers) {
this.serializers = serializers;
}
@Override
protected void decode(final ChannelHandlerContext channelHandlerContext, final ByteBuf byteBuf, final List<Object> objects) throws Exception {
if (byteBuf.readableBytes() < 1) {
return;
}
final byte lenOfContentType = byteBuf.readByte();
if (byteBuf.readableBytes() < lenOfContentType) {
byteBuf.resetReaderIndex();
return;
}
final ByteBuf contentTypeBytes = channelHandlerContext.alloc().buffer(lenOfContentType);
try {
byteBuf.readBytes(contentTypeBytes);
final String contentType = contentTypeBytes.toString(UTF8);
final MessageSerializer serializer = select(contentType, Serializers.DEFAULT_REQUEST_SERIALIZER);
channelHandlerContext.channel().attr(StateKey.SERIALIZER).set(serializer);
channelHandlerContext.channel().attr(StateKey.USE_BINARY).set(true);
try {
objects.add(serializer.deserializeRequest(byteBuf.discardReadBytes()));
} catch (SerializationException se) {
objects.add(RequestMessage.INVALID);
}
} finally {
contentTypeBytes.release();
}
}
public MessageSerializer select(final String mimeType, final MessageSerializer defaultSerializer) {
if (logger.isWarnEnabled() && !serializers.containsKey(mimeType))
logger.warn("Gremlin Server is not configured with a serializer for the requested mime type [{}] - using {} by default",
mimeType, defaultSerializer.getClass().getName());
return serializers.getOrDefault(mimeType, defaultSerializer);
}
}