nng_sender.cpp

//
// Created by Johannes Mey on 26.05.20.
//

#include "ros/ros.h"
#include "std_msgs/String.h"

#include <nng/nng.h>
#include <nng/protocol/pubsub0/pub.h>

std::string url = "tcp://localhost:6576";

nng_socket sock;
int rv;

void nngCallback(const std_msgs::String::ConstPtr &msg) {
  ROS_INFO("sending via NNG: [%s]", msg->data.c_str());
  if ((rv = nng_send(sock, (void *) msg->data.c_str(), msg->data.length(), 0)) != 0) {
    ROS_ERROR_STREAM("nng_send returned: " << nng_strerror(rv));
  }
}

int main(int argc, char **argv) {
  ros::init(argc, argv, "nng_sender");

  ros::NodeHandle n("nnc_test");

  if ((rv = nng_pub0_open(&sock)) != 0) {
    ROS_ERROR_STREAM("nng_pub0_open returned: " << nng_strerror(rv));
  }
  if ((rv = nng_listen(sock, url.c_str(), nullptr, 0)) < 0) {
    ROS_ERROR_STREAM("nng_listen returned: " << nng_strerror(rv));
  }

  ros::Subscriber sub = n.subscribe("send_nng", 1000, nngCallback);

  ros::spin();

  return 0;
}