C++ protobuf，ZMQ。 客户端-服务器接口的功能

Question

While I doing program server-client on C++, using ZMQ and protobufs from Google, touched functions related with variance of types.

Problem: functions ParseFromString and SerializeToString use string type as parameter, but I need write program using zmq::message_t such as a parameter.

Proto file:
package core;
{ message Request
required uint32 id=1;
required uint32 class_id=2;
...}

zmq::message_t msg; // beginning
core::Request reqt;
…
socket.recv(&msg) ;// receiving messgae, socket.recv(reqt) doesn't work
ParseFromString (msg); //serialization to structure doesn’t work

Program is a client-server execution using sockets Need to coordinate variables string type and message between each other. Functions ParseFromString() и SerializeToString(). В Python все просто: socket.send(reqt.SerializeToString()) и class_id=reqt.ParseFromString(socket.recv)

Answer 1

You should use ParseFromArray() :

reqt.ParseFromArray(msg.data(), msg.size());

On the serializing side, use ByteSize() to get the size of the protobuf message, allocate space for it, then SerializeToArray() to write the bytes into the space.

Full documentation on these methods and others can be found at:

https://developers.google.com/protocol-buffers/docs/reference/cpp/google.protobuf.message_lite

Answer 2

(&string_obj) != string_obj.c_str()

https://github.com/junhyeokahn/zmq-protobuf/blob/master/cpp-py/publisher.cpp