I should have been more clear about how I'm reading the stream on the python server side .....
I consume the 4 byte length header before calling message_capnp.Message.read(socket) as I cannot see how to read the payload directly and then offer the bytes to capnp in lieu of having capnp read directly from the socket. So those header bytes are not accidentally being read by message_capnp.Message.read(socket). On Thursday, September 10, 2020 at 10:26:24 AM UTC-4 Robert Olivier wrote: > I've scoured the net for a solid example of using capnp purely as a data > interchange format sans RPC, streaming over TCP and dont see it. I like the > design concept of capnp vs competitors and I want to use it in place of > ASN.1 generated code for a project. > > However, the documentation is just so scattered and unclear that I can't > get a basic test structure sucessfully sent to a python process. > > I've implemented my own simple framing, consisting of a 4 byte length that > c++ sends to python before the message. I compute the payload length as > computeSerializedSizeInWords() * sizeof(capnp::word) and then send it, > using an kj::OutputStream subclass that sends the data via ASIO. > > My python process reads the length and payload, but when I try to create > the message with > message_capnp.Message.read(socket) I get a message has too many segments > error. > > I have read that vague bit in the Encoding | Serialization Over a Stream > section of the home page docs and I cannot tell if that is saying I need to > implement that on both sides of the wire, or if capnp::writeMessage() > implements that. > > Is there some documentation that I'm missing? Seems strange that such a > common use case would be effectively undocumented! Is use as a pure > data-interchange format discouraged? > > rjo > -- You received this message because you are subscribed to the Google Groups "Cap'n Proto" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To view this discussion on the web visit https://groups.google.com/d/msgid/capnproto/3fe1dde2-5e30-496b-9469-ab00b946113en%40googlegroups.com.
