Netty and Protobuf in HTTP content

Question

I have incoming HTTP requests with protobuf message in the HTTP content. So far I managed to use the Snoop (HTTP server) example and modify the handler part to parse the HTTP content into protobuf message and back to bytes for output. But I guess this is not the optimal way to do this.

Is it possible to use the built-in Protobuf encoder/decoder in Netty in the pipeline? So first HTTPResponseDecoder (or something more convenient) "chops" off the header and passes only the content part to the FrameDecoder + ProtobufDecoder then passes the message to myAppHandler where business logic is applied?

I am a bit confused how message (or part of it) is passed to the next handler. Or am I on totally on the wrong track here?

Maybe a link to an example using protobuf with HTTP content would also serve as an explanation if there's any.

Thnx in advance.

Answer 1

Thank you for the silent support :]

The solution is to use HttpObjectAggregator() and simply write a handler taking care of the byte-to-message process using the FullHttpRequest from the aggregator handler. The output of this decoder is the protobuf message:

public class ProtoRequestDecoder extends MessageToMessageDecoder<FullHttpRequest> {
    @Override
    protected void decode(ChannelHandlerContext ctx, FullHttpRequest msg, List<Object> out) throws Exception {


        byte[] payloadBytes = new byte[msg.content().readableBytes()];
        msg.content().readBytes(payloadBytes);

        MyMessage protoMessage = MyMessage.parseFrom(payloadBytes);

        out.add(protoMessage);

    }
}