In MetaTrader 5 I write data to a socket like MQL5 Document example in an Expert Advisors and the data sent to a Node.js TCP server like a charm. But MetaTrader cannot get the response. I don't know what's wrong. If anyone can advise on this.
MQL5 Expert code:
//+------------------------------------------------------------------+
//| SocketExample.mq5 |
//| Copyright 2018, MetaQuotes Software Corp. |
//| https://www.mql5.com |
//+------------------------------------------------------------------+
#property copyright "Copyright 2018, MetaQuotes Software Corp."
#property link "https://www.mql5.com"
#property version "1.00"
#property description "Add Address to the list of allowed ones in the terminal settings to let the example work"
#property script_show_inputs
input string Address="127.0.0.1";
input int Port =3100;
bool ExtTLS =false;
//+------------------------------------------------------------------+
//| Send command to the server |
//+------------------------------------------------------------------+
bool HTTPSend(int socket,string request)
{
char req[];
int len=StringToCharArray(request,req)-1;
if(len<0)
return(false);
//--- if secure TLS connection is used via the port 443
if(ExtTLS)
return(SocketTlsSend(socket,req,len)==len);
//--- if standard TCP connection is used
return(SocketSend(socket,req,len)==len);
}
//+------------------------------------------------------------------+
//| Read server response |
//+------------------------------------------------------------------+
bool HTTPRecv(int socket,uint timeout)
{
char rsp[];
string result;
uint timeout_check=GetTickCount()+timeout;
//--- read data from sockets till they are still present but not longer than timeout
do
{
uint len=SocketIsReadable(socket);
if(len)
{
int rsp_len;
//--- various reading commands depending on whether the connection is secure or not
if(ExtTLS)
rsp_len=SocketTlsRead(socket,rsp,len);
else
rsp_len=SocketRead(socket,rsp,len,timeout);
//--- analyze the response
if(rsp_len>0)
{
result+=CharArrayToString(rsp,0,rsp_len);
//--- print only the response header
int header_end=StringFind(result,"\r\n\r\n");
if(header_end>0)
{
Print("HTTP answer header received:");
Print(StringSubstr(result,0,header_end));
return(true);
}
}
}
}
while(GetTickCount()<timeout_check && !IsStopped());
return(false);
}
//+------------------------------------------------------------------+
//| Script program start function |
//+------------------------------------------------------------------+
void OnTick()
{
double closePrice = iClose(Symbol(), Period(), 0);
string priceStr = DoubleToString(closePrice);
int socket=SocketCreate();
//--- check the handle
if(socket!=INVALID_HANDLE)
{
//--- connect if all is well
if(SocketConnect(socket,Address,Port,1000))
{
Print("Established connection to ",Address,":",Port);
string subject,issuer,serial,thumbprint;
datetime expiration;
//--- if connection is secured by the certificate, display its data
if(SocketTlsCertificate(socket,subject,issuer,serial,thumbprint,expiration))
{
Print("TLS certificate:");
Print(" Owner: ",subject);
Print(" Issuer: ",issuer);
Print(" Number: ",serial);
Print(" Print: ",thumbprint);
Print(" Expiration: ",expiration);
ExtTLS=true;
}
//--- send GET request to the server
if(HTTPSend(socket, priceStr))
{
Print("GET request sent");
//--- read the response
if(!HTTPRecv(socket,1000))
Print("Failed to get a response, error ",GetLastError());
}
else
Print("Failed to send GET request, error ",GetLastError());
}
else
{
Print("Connection to ",Address,":",Port," failed, error ",GetLastError());
}
//--- close a socket after using
SocketClose(socket);
}
else
Print("Failed to create a socket, error ",GetLastError());
}
//+------------------------------------------------------------------+
This Expert contains two methods to send and get data over the socket.
HTTPSend Write data to socket and
HTTPRecvRead server response and get data from the socket but this method return false and this message Failed to get a response, error 5275.
Node.js server code:
const net = require('net');
const port = 3100;
const host = '127.0.0.1';
const server = net.createServer();
server.listen(port, host, () => {
console.log('TCP Server is running on port ' + port + '.');
});
let sockets = [];
server.on('connection', function(sock) {
console.log('CONNECTED: ' + sock.remoteAddress + ':' + sock.remotePort);
sockets.push(sock);
sock.on('data', function(data) {
console.log('DATA ' + sock.remoteAddress + ': ' + data);
// Write the data back to all the connected, the client will receive it as data from the server
sockets.forEach(function(sock, index, array) {
sock.write(sock.remoteAddress + ':' + sock.remotePort + " said " + data + '\n');
});
});
// Add a 'close' event handler to this instance of socket
sock.on('close', function(data) {
let index = sockets.findIndex(function(o) {
return o.remoteAddress === sock.remoteAddress && o.remotePort === sock.remotePort;
})
if (index !== -1) sockets.splice(index, 1);
console.log('CLOSED: ' + sock.remoteAddress + ' ' + sock.remotePort);
});
});
