Send component data via zmq socket

[bgarcial]

I have my ZMQServerComponent.h file in which I declare, the Data<double> myparam; variable:

#include <sofa/core/behavior/BaseController.h>
#include <zmq.hpp>

namespace sofa
{
namespace component
{
namespace controller
{

class ZMQServerComponent : public sofa::core::behavior::BaseController
{
public:
    SOFA_CLASS(ZMQServerComponent, sofa::core::behavior::BaseController);
    Data<double> myparam;

    ZMQServerComponent ();
    virtual ~ZMQServerComponent ();
    void receiveRequests();
    void sendReplyToClient();
    void init();    
};
}
}
}

In my ZMQServerComponent.cpp I have the goal of send the Data<double> myparam;
via zmq socket with the objective of send through zeroMQ some data from SOFA.
This I perform in my sendReplyToClient() function …

Then, according to previously mentioned I have the following component:

#include "ZMQServerComponent.h"
#include <sofa/core/ObjectFactory.h>
#include <zmq.hpp>
#include <iostream>

using std::cout;
using std::endl;
using std::string;

namespace sofa
{
namespace component
{
namespace controller
{

zmq::context_t context (1);
zmq::socket_t socket (context, ZMQ_REP);

ZMQServerComponent::ZMQServerComponent() 
    : myparam(initData(&myparam, 0.42, "myparam", "ZeroMq version plugin. "))
{}

void ZMQServerComponent::receiveRequests() {
    cout << "Creating socket zeroMQ ..."<<endl;
    socket.bind("tcp://*:5555");
    zmq::message_t request;

    //  Wait for next request from client
    socket.recv(&request);
    string incomingMessage = std::string(static_cast<char *>(request.data()), request.size());
    cout << "Incoming message from client" << incomingMessage << endl;

    // Do some work
    sleep(1);
}

// I send data in response to client
void ZMQServerComponent::sendReplyToClient() {
    zmq::message_t reply (30);

    // Sending the response to client via zmq - Does not works
    memcpy (reply.data(), "Hello Client, my version is: ", myparam.getValue()); 

    // Show the myparam value. This works
    cout << "myparam value is:" << myparam.getValue() << endl;
    //memcpy (reply.data(), "Hello Client", myparam.getValue()); 
    socket.send(reply);
}

void ZMQServerComponent::init(){
    ZMQServerComponent z;
    z.receiveRequests();
    z.sendReplyToClient();
}

ZMQServerComponent::~ZMQServerComponent()
{}

SOFA_DECL_CLASS(ZMQServerComponent)
int ZMQServerComponentClass = sofa::core::RegisterObject("This component create a Socket.").add<ZMQServerComponent>();

}
}
}

In my client, which is a python script, I have:

import zmq

context = zmq.Context()

#  Socket to talk to server
print("Connecting to ZMQ server…")
socket = context.socket(zmq.REQ)
socket.connect("tcp://localhost:5555")
socket.send(b" Hello ZMQ Server, What is your version")

#  Get the reply.
message = socket.recv()
print("Received reply %s" % message)

When I send the data from client to Server, In my C++ Server I get:

bgarcial@elpug : ~/workspace/sofa/build/v17.06
[0] % ./bin/runSofa      

[ERROR]   [PluginManager] Plugin loading failed (/home/bgarcial/workspace/sofa/build/v17.06/lib/libZeroMq.so): function initExternalModule() not found
Creating socket zeroMQ ...
Incoming message from client Hello ZMQ Server, What is your version
myparam value is:0.42

And in the client I get:

[2] % python client.py   
Connecting to ZMQ server…
Received reply b'\xdc\xd7\x00\xf0\xc3\x7f\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00'
(cnvss_tests) 
bgarcial@elpug ‹ master ●● › :

Apparently the server response does not arrive or arrive a empty string …

I have some doubts, if I should perform some cast or message conversion (is a double data type from server) in my python client or form C++ Server this message does not sending. I think this latest option, may be …

In the server side, I can show the myparam value but this is are not send to client …

Ho to can I response to client with the SOFA component parameter value?

[bgarcial]

I’ve changed the python client to c++ client of this way:
This c++ client is an external application out from SOFA

#include <zmq.hpp>
#include <string>
#include <iostream>
#include <time.h>
#include <sys/time.h>

using std::cout;
using std::cin;
using std::endl;
using std::string;

int main ()
{
    //  Prepare our context and socket
    std::string message="Toes Server";
    zmq::context_t context (1);
    zmq::socket_t socket (context, ZMQ_REQ);

    // Llamamos el proceso al cual le queremos medir el tiempo
    cout << "Conecct to ZMQ Server" << endl;
    socket.connect ("tcp://localhost:5555");

    zmq::message_t request (message.length());
    memcpy (request.data (), message.c_str(), message.length());
    //std::cout << "Sending " << request.data() << "…" << std::endl;
    socket.send (request);

    zmq::message_t reply;
    socket.recv (&reply);
    string replyMessage = string(static_cast<char *>(reply.data()), reply.size());

    cout << "Received message from server: " + replyMessage << " "  << endl;
    return 0;

}

I execute the client after the server and I receive the following output:

bgarcial@elpug ‹ master ●● › : ~/CLionProjects/zeroMQ_C++_Client-Python_Server
[0] % ./client_get-time-of-day.out                                      
Conecct to ZMQ Server
Received message from server: ��y����y����n?� 
bgarcial@elpug ‹ master ●● › : ~/CLionProjects/zeroMQ_C++_Client-Python_Server

The response from ZMQ server is an strange string or binary. I think that my response is not arrive on the client side or this should be converted, by I unknown how to do it..

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