ZeroMQ Client/Server - ROUTER/DEALER Minimal Example

client.cpp

#include <iostream>
#include <zmq.hpp>
#include <string>
#include <thread>
#include <chrono>

int main() {
    zmq::context_t context(1);
    zmq::socket_t socket(context, ZMQ_ROUTER);
    socket.bind("tcp://*:5555");
    getchar();
    try {
        // Send JobRequest to camera to run
        zmq::message_t request (10);
        memcpy (request.data (), "JobRequest", 10);
        std::cout << "Router: Sending JobRequest " << std::endl;
        // Set the address, then the empty delimiter and then the request itself
        socket.send("A", ZMQ_SNDMORE);
        socket.send(zmq::message_t(), ZMQ_SNDMORE);
        socket.send(request);

        // Receive the reply from the camera
        std::cout << "Router: Waiting for reply from camera " << std::endl;
        zmq::message_t replyID(0);
        zmq::message_t reply(0);
        socket.recv(&replyID);
        socket.recv(&reply);

        std::cout << "Router: Received " <<  std::string(static_cast<char*>(reply.data()), reply.size()) << std::endl;
    } catch (std::exception e) {
        std::cout << "Router Error: " << e.what();
    }

    std::this_thread::sleep_for(std::chrono::seconds(1));
    socket.setsockopt(ZMQ_LINGER, 0);
    socket.close();
    context.close();
}

server.cpp

#include <zmq.hpp>
#include <string>
#include <iostream>
#include <thread>

int main (void)
{
    //  Prepare our context and socket
    zmq::context_t context (1);
    zmq::socket_t socket (context, ZMQ_DEALER);

    std::cout << "Dealer: Connecting to RunJob server… \n";
    socket.setsockopt(ZMQ_IDENTITY, "A", 1);
    socket.connect ("tcp://localhost:5555");

    while(1) {
        try {
            // Wait for next request from client
            std::cout << "Dealer: Waiting for request" << std::endl;
            zmq::message_t request(0);

            // Receive request
            socket.recv(&request);

            std::cout << "Dealer: Received request" << std::endl;
            std::cout << std::string(static_cast<char*>(request.data()),request.size()) << std::endl;

            // Do some processing to the request here

            // Send reply back to client
            std::string string= "JobCompleted";
            zmq::message_t message(string.size());
            memcpy (message.data(), string.data(), string.size());
            std::cout << "Router: Sending" << std::endl;

            // ZMQ_SNDMORE - "Specifies that the message being sent is a multi-part message, and that further message parts are to follow"
            socket.send(zmq::message_t(), ZMQ_SNDMORE);
            socket.send(message);

        }catch (std::exception e) {
            std::cout << "Router Error: " << e.what();
        }
    }

    // Used to set various 0MQ Socket Settings
    // ZMQ_Linger - Set linger period for socket shutdown
    socket.setsockopt(ZMQ_LINGER, 0);
    socket.close();
    context.close();

    return 0;
}