Python zmq SUB套接字未接收到MQL5 Zmq PUB套接字 [英] MQL5 Zmq PUB socket not being received by Python zmq SUB socket

问题描述

我正在尝试在MQL5中设置一个PUB套接字，并在Python中设置一个将接收消息的SUB套接字.

I'm trying to set up a PUB socket in MQL5 and a SUB socket in Python that will receive messages.

我在MQL5中拥有这个:

I have this in MQL5:

#include <Zmq/Zmq.mqh>

Context context("helloworld");
Socket socket(context,ZMQ_PUB);

string BROKER;

int OnInit()
{
   if (socket.bind("tcp://*:5556"))
   {
       Print("Error");
   }
   else
       Print("Bound");
   BROKER = AccountInfoString(ACCOUNT_COMPANY);
   return(INIT_SUCCEEDED);
}

void OnTick()
{  
   MqlTick last_tick; 
   string str;
   if(SymbolInfoTick(Symbol(),last_tick)) 
   { 
      StringConcatenate(str, BROKER, ",", Symbol(), ",", last_tick.time_msc, ",", last_tick.ask, ",", last_tick.bid, ",", last_tick.last, ",", last_tick.volume); 
   } 
   else 
      str = "FAIL";

   Print(str);
   ZmqMsg reply(str);
   socket.send(reply);
}

这在Python中:

import zmq
import random
import sys
import time

context = zmq.Context()
socket = context.socket(zmq.SUB)

ports = [5556]
for port in ports:
    print(port)
    socket.connect("tcp://localhost:{}".format(port))
socket.setsockopt_string(zmq.SUBSCRIBE, '')

print('connected')

f = open('metatrader-1.csv', 'a')
while True:
    msg = socket.recv()
    print(msg)
    f.write(str(msg) + '\n')

这个问题是，Python端似乎没有收到任何东西，recv调用将永远阻塞.因为可以看到打印件，所以在MT中触发了OnTick方法.

This problem is that this does not seem to receive anything on the Python side, the recv call just blocks forever. The OnTick method is fired in MT, since the prints can be seen.

如何使它正常工作?

请注意，如果我切换到REP/REQ对，它将起作用.

Note that if I switch to a REP/REQ pair, it works.

MQL5:

#include <Zmq/Zmq.mqh>


Context context("helloworld");
Socket socket(context,ZMQ_REQ);

string BROKER;

int OnInit()
{
   if (socket.connect("tcp://localhost:5555"))
   {
      Print("Error");
   }
   else
      Print("Bound");
   BROKER = AccountInfoString(ACCOUNT_COMPANY);
   return(INIT_SUCCEEDED);
}

void OnTick()
{  
   MqlTick last_tick; 
   string str;
   if(SymbolInfoTick(Symbol(),last_tick)) 
   { 
      StringConcatenate(str, BROKER, ",", Symbol(), ",", last_tick.time_msc, ",", last_tick.ask, ",", last_tick.bid, ",", last_tick.last, ",", last_tick.volume); 
   } 
   else 
      str = "FAIL";

   Print(str);
   ZmqMsg reply(str);
   socket.send(reply);
   socket.recv(reply);
}

Python:

import zmq
import random
import sys
import time

context = zmq.Context()
socket = context.socket(zmq.REP)

ports = [5555]
for port in ports:
    print(port)
    socket.bind("tcp://*:{}".format(port))
#socket.setsockopt_string(zmq.SUBSCRIBE, '')

print('connected')

f = open('metatrader-1.csv', 'a')
while True:
    msg = socket.recv()
    socket.send_string('ack')
    print(msg)
    f.write(str(msg) + '\n')

但这有一些缺点，所以如果可以的话，我宁愿不使用它.

But this has some drawbacks so I'd rather not use this if I can help it.

推荐答案

您的套接字选项必须放在套接字连接之前，因此您的代码将是:

Your socket option must be placed before the socket connection, so your code will be:

import zmq
import random
import sys
import time

context = zmq.Context()
socket = context.socket(zmq.SUB)

ports = [5556]
socket.setsockopt(zmq.SUBSCRIBE, b"")  # Note.

for port in ports:
    print(port)
    socket.connect("tcp://localhost:{}".format(port))

print('connected')

f = open('metatrader-1.csv', 'a')
while True:
    msg = socket.recv()
    print(msg)
    f.write(str(msg) + '\n')

此外，这部分:

if (socket.bind("tcp://*:5556"))
{
   Print("Error");
}
else
   Print("Bound");

应该是相反的方式.成功绑定套接字后，这实际上会显示一个错误.

Should be the other way around. This will actually print an error when the socket is successfully bound.

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