Question

I need to exchange both protobuf-net objects and files between computers and am trying to figure out the best way to do that. Is there a way for A to inform B that the object that follows is a protobuf or a file? Alternately, when a file is transmitted, is there a way to know that the file has ended and the Byte[] that follows is a protobuf?

Using C# 4.0, Visual Studio 2010

Thanks, Manish

Answer 1

This has nothing to do with protobuf or files, and everything to do with your comms protocol, specifically “framing”. This means simply: how you demark sub-messages in a single stream. For example, if this is a raw socket you might choose to send (all of)

• a brief message-type, maybe a byte: 01 for file, 02 for a protobuf message of a particular file
• a length prefix (typically 4 bytes network-byte-order)
• the payload, consisting of the previous number of bytes

Then rinse and repeat for each message.

You don’t state what comms you are asking, so I can be more specific.

Btw, another approach would be to treat a file as a protobuf message with a byte[] member – mainly suitable for small files, though