TCP Server Connection

AlperenUnal

Hello everyone,

I am trying to communicate between QT Creator and nodeMCU and I want to use QT Creator as a server mission and use nodeMCU as a client. At nodeMCU, I wrote the code for client and I can communicate over Telnet but I can not communicate over QT Creator. At QT Creator, I can only communicate with my computer local host but I couldn't connect to the nodeMCU. What should I do? My nodeMCU has 192.168.1.104 IP addresses and I will communicate over the 8888 port.

My cpp code is like this for the QT Creator.

#include "myserver.h"

MyServer::MyServer(QObject *parent) : QObject(parent)
{
server =new QTcpServer(this);
connect(server,SIGNAL(newConnection()),this,SLOT(newConnection()));

if(!server->listen(QHostAddress("127.0.0.1"),23))
{
    qDebug()<<"Server couldn't started!";
}
else
{
    qDebug()<<"Server started!";
}

}

void MyServer::newConnection()
{

QTcpSocket *socket =server->nextPendingConnection();

socket->write("hello \r\n");
socket->flush();
socket->waitForBytesWritten(2000);
socket->close();

}

Christian Ehrlicher

@AlperenUnal said in TCP Server Connection:

QHostAddress("127.0.0.1")

You listen on 127.0.0.1 (localhost) - so how should a client be able to connect to this client at 192.168.1.104 then?

JonB

@AlperenUnal
Firstly Qt Creator is just an IDE for editing/debugging programs. Qt Creator is not relevant here. What might matter is for you to state what version of Qt itself you are using?

My nodeMCU has 192.168.1.104 IP addresses and I will communicate over the 8888 port.

How is that related to you using server->listen(QHostAddress("127.0.0.1"),23) then?

At nodeMCU, I wrote the code for client and I can communicate over Telnet

Not sure what you mean about "communicate over Telnet " if your nodeMCU is a client? In any case what command do you use for telnet in case it is relevant?

AlperenUnal

@Christian-Ehrlicher

I couldn't figure out what should I wrote for connection with the nodeMCU IP adress :(

AlperenUnal

@JonB

Actually, I was trying to say that from telnet screen I wrote open 127.0.0.1 23, and I could see which signal has been sent.

Actually my main goal is sending a command signal like 'E' or 'H' to the nodeMCU from QTCreator and then with reading these values from nodeMCU, I will try to blink LED. Could you please help me?

Christian Ehrlicher

@AlperenUnal said in TCP Server Connection:

I couldn't figure out what should I wrote for connection with the nodeMCU IP adress :(

Then simply listen to all interfaces -> https://doc.qt.io/qt-5/qtcpserver.html#listen
"If address is QHostAddress::Any, the server will listen on all network interfaces."

AlperenUnal

@Christian-Ehrlicher
Okey, I will try it, thanks for the help :)