Question

I know it can be used to send/receive structured object from file,

but can it be used to send/receive sequences of structured object from a socket?

http://code.google.com/p/protobuf/

Answer 1

Protocol Buffers is a structured data serialization (and de-serialization) framework. It is only concerned with encoding a selection of pre-defined data types into a data stream. What you do with that stream is up to you. To quote the wiki:

If you want to write multiple messages
to a single file or stream, it is up
to you to keep track of where one
message ends and the next begins. The
Protocol Buffer wire format is not
self-delimiting, so protocol buffer
parsers cannot determine where a
message ends on their own. The easiest
way to solve this problem is to write
the size of each message before you
write the message itself. When you
read the messages back in, you read
the size, then read the bytes into a
separate buffer, then parse from that
buffer.

So yes, you could use it to send/receive multiple objects via a socket but you have to do some extra work to differentiate each object stream.