谁能告诉我这个ZeroMQ代码有什么问题吗？

Question

I have tried a variety of different things but this is essentially what I am trying to do. Have an in process pubsub set up. I reran this code and I am getting a connection refused on the attempt to connect a pub socket to the front end of the forwarder device.

Here is the code

string expectedAddress = "XXXX";
        string message = "hello its me";
        int count = 0;
        using (var context = ZmqContext.Create())
        {
            using (var forwarderDevice = new ForwarderDevice(context, "inproc://front", "inproc://back", DeviceMode.Threaded))
            {
                using (var pub = Helper.GetConnectedPublishSocket(context, "inproc://front"))
                {
                    using (var sub = Helper.GetConnectedSubscribeSocket(context, "inproc://back")) 
                    {
                        forwarderDevice.Start();

                        Helper.SendOneSimpleMessage(expectedAddress, message, pub);

                        var zmqMessage = Helper.ReceiveMessage(sub);

                        Assert.AreEqual(count, zmqMessage.FrameCount);
                        Frame frame = zmqMessage[0];
                        var address = Encoding.Unicode.GetString(frame.Buffer);
                        Assert.AreEqual(expectedAddress, address);
                    }
                }
                forwarderDevice.Stop();
            }
        }

Ok First thing I know I am doing wrong... the start should come directly after the creation of the device, before you attempt to connect to it. Second thing is that the device is started on another thread and may not be ready by the time the main thread attempts to connect so you need to block some how until it is ready. Code now looks like:

string expectedAddress = "XXXX";
        string message = "hello its me";
        int count = 0;
        using (var context = ZmqContext.Create())
        {
            using (var forwarderDevice = new ForwarderDevice(context, "inproc://front", "inproc://back", DeviceMode.Threaded))
            {
                forwarderDevice.Start();
                while (!forwarderDevice.IsRunning)
                { }

                using (var pub = Helper.GetConnectedPublishSocket(context, "inproc://front"))
                {
                    using (var sub = Helper.GetConnectedSubscribeSocket(context, "inproc://back")) 
                    {
                        Task<ZmqMessage> task = Task.Run(() =>
                            {
                                var zmqMessage = Helper.ReceiveMessage(sub);
                                return zmqMessage;
                            });

                        Helper.SendOneSimpleMessage(expectedAddress, message, pub);
                        task.Wait();

                        var result = task.Result;

                        Assert.AreEqual(count, result.FrameCount);
                        Frame frame = result[0];
                        var address = Encoding.Unicode.GetString(frame.Buffer);
                        Assert.AreEqual(expectedAddress, address);
                    }
                }
                forwarderDevice.Stop();
            }
        }

I am not getting any errors but I never receive the message either

Answer 1

Just looking at the latter bit of code, a classic SUB error is not to actually subscribe to anything - you need to setsockopt to SUBSCRIBE to "" (empty string) to get every message. So, if that is a PUB/SUB socket pair, unless you're subscribing in the helper it will just be filtering the messages.