How to implement Pub-Sub Network with a Proxy by using XPUB and XSUB in ZeroMQ(C++)?

Question

I am a newcomer to zeromq. Recently I did some tests on pub/sub of zeromq, and I don\'t konw how to implement Pub-Sub Network with a Proxy by using XPUB and XSUB in ZeroMQ. Hope

Answer 1

Learn the basics by working through the examples. For the proxy, just use this, it's from msgqueue.cpp

int main (int argc, char *argv[])
{
    zmq::context_t context(1);
    zmq::socket_t frontend (context, ZMQ_XSUB);
    frontend.bind("tcp://*:5559");
    zmq::socket_t backend (context, ZMQ_XPUB);
    zmq_bind (backend, "tcp://*:5560");
    zmq_proxy (frontend, backend, NULL);
    return 0;
}

Answer 2

Proxy:

int main (int argc, char *argv[])
{
zmq::context_t context(1);
zmq::socket_t frontend (context, ZMQ_XSUB);
....//set hwm
frontend.bind("tcp://*:5559");
zmq::socket_t backend (context, ZMQ_XPUB);
....//set hwm
zmq_bind (backend, "tcp://*:5560");
zmq_proxy (frontend, backend, NULL);
return 0;
}

The reason I lost message is that I should have called setsockopt before bind or connect.

Refer to 0MQ API documentation for setsockopt:

Caution: All options, with the exception of ZMQ_SUBSCRIBE, ZMQ_UNSUBSCRIBE and ZMQ_LINGER, only take effect for subsequent socket bind/connects.