Question

我尝试运行简单的ZMQ应用程序（ROUTER / DEALER）。

我只是将DEALER的请求发送给ROUTER，然后将其发回。但是DEALER无法接收它。

我在一个进程中运行它（ROUTER有自己的线程）。

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

void router()
{
    zmq::context_t context(1);
    zmq::socket_t socket(context, ZMQ_ROUTER);
    socket.bind("tcp://*:5561");

    while(1)
    {
        //  Wait for next request from client
        zmq::message_t reply;
        socket.recv (&reply);

        std::cout << "Router: Received request" << std::endl;

        //  Send reply back to client
        std::string string= "example";
        zmq::message_t message(string.size());
        memcpy (message.data(), string.data(), string.size());

        std::cout << "Router: Sending" << std::endl;
        socket.send (message);
    }
}

int main ()
{
    std::thread t{&router};

    //  Prepare our context and socket
    zmq::context_t context (2);
    zmq::socket_t socket (context, ZMQ_DEALER);

    std::cout << "Dealer: Connecting to hello world server…" << std::endl;
    socket.connect ("tcp://127.0.0.1:5561");

    for (int i = 0; i != 10; i++)
    {
        zmq::message_t request (5);
        memcpy (request.data (), "Hello", 5);
        std::cout << "Dealer: Sending Hello " << i << "…" << std::endl;
        socket.send (request);

        zmq::message_t reply;
        socket.recv (&reply);
        std::cout << "Dealer: Received " << i << std::endl;
    }
    return 0;
}

我有一个输出：

Dealer: Connecting to hello world server…
Dealer: Sending Hello 0…
Router: Received request
Router: Sending
Router: Received request
Router: Sending

Answer 1

来自socket上的ZMQ's documentation：

当接收消息时，ZMQ_ROUTER套接字应该预先添加消息包含消息的始发对等体的标识的部分在将它传递给应用程序之前。收到的消息是从所有相互关联的同行中排队等候。发送消息时 ZMQ_ROUTER套接字应删除消息的第一部分并使用它确定消息应被路由的对等体的身份到。

所以将代码修改为：

#include <zmq.hpp>
#include <string>
#include <iostream>
#include <thread>
#include <unistd.h>
void router()
{
    zmq::context_t context(1);
    zmq::socket_t socket(context, ZMQ_ROUTER);
    socket.bind("tcp://*:5561");

    while(1) // Fix that infinite loop or your thread won't join
    {
        //  Wait for next request from client
        zmq::message_t id;
        socket.recv (&id);

        zmq::message_t reply;
        socket.recv (&reply);
        std::cout << std::string(static_cast<char*>(reply.data()),reply.size()) << std::endl;
        std::cout << "Router: Received request" << std::endl;

        //  Send reply back to client
        zmq::message_t copy_id;
        copy_id.copy(&id);
        std::string string= "example";
        zmq::message_t message(string.size());
        memcpy (message.data(), string.data(), string.size());
        std::cout << "Router: Sending" << std::endl;
        socket.send(id, ZMQ_SNDMORE);
        socket.send(message);
    }
    sleep(1);
    socket.setsockopt(ZMQ_LINGER, 0);
    socket.close();
    context.close();
}

int main ()
{
    std::thread t{&router};

    //  Prepare our context and socket
    zmq::context_t context (2);
    zmq::socket_t socket (context, ZMQ_DEALER);

    std::cout << "Dealer: Connecting to hello world server…" << std::endl;
    socket.connect ("tcp://127.0.0.1:5561");

    for (int i = 0; i != 10; i++)
    {
        zmq::message_t request (5);
        memcpy (request.data (), "Hello", 5);
        std::cout << "Dealer: Sending Hello " << i << "…" << std::endl;
        socket.send(request);

        zmq::message_t reply;
        socket.recv(&reply);
        std::cout << "Dealer: Received " << i << std::endl;
    }
    socket.setsockopt(ZMQ_LINGER, 0);
    socket.close();
    context.close();
    t.join();
    return 0;
}

ZMQ Hello world不起作用

1 个答案: