Multi threaded TCP server GUI using Qt widgets application

Christian Ehrlicher

Qt has a threaded server example: https://doc.qt.io/qt-5/qtnetwork-threadedfortuneserver-example.html

fari35

@Christian-Ehrlicher I know how to make a threaded tcp server console application but I am having issues in making a gui of it. I have edited my question you can see the error there.

Christian Ehrlicher

You should also define your function MyServer::startServer() I would guess.

fari35

@Christian-Ehrlicher yes its defined in server.h file :

void MyServer::startServer()
{
    int port = 54000;

    if(!this->listen(QHostAddress::Any,port))
    {
        qDebug() << "Could not start server";
    }
    else
    {
        qDebug() << "Listening to port " << port << "...";
    }
}

I am using the same code as in this link:"https://www.bogotobogo.com/Qt/Qt5_QTcpServer_Multithreaded_Client_Server.php"

Christian Ehrlicher

And you added the server.cpp to your pro-file?

fari35

@Christian-Ehrlicher yes, see I have added all the files:

QT       += core
QT       +=network
QT       +=gui
greaterThan(QT_MAJOR_VERSION, 4): QT += widgets

CONFIG += c++11

# You can make your code fail to compile if it uses deprecated APIs.
# In order to do so, uncomment the following line.
#DEFINES += QT_DISABLE_DEPRECATED_BEFORE=0x060000    # disables all the APIs deprecated before Qt 6.0.0
TEMPLATE = app
SOURCES += \
    main.cpp \
    mainwindow.cpp
    myserver.cpp
    mythread.cpp

HEADERS += \
    mainwindow.h
    myserver.h
    mythread.h

FORMS += \
    mainwindow.ui

# Default rules for deployment.
qnx: target.path = /tmp/$${TARGET}/bin
else: unix:!android: target.path = /opt/$${TARGET}/bin
!isEmpty(target.path): INSTALLS += target

Christian Ehrlicher

@fari35 said in Multi threaded TCP server GUI using Qt widgets application:

> SOURCES += \
>     main.cpp \
>     mainwindow.cpp
>     myserver.cpp
>     mythread.cpp

This does not look correct - you forgot the \

fari35

@Christian-Ehrlicher Do I need to put this \ in front of every file?

JonB

@fari35
No, it's a line continuation character. It must go at the end of each line in a list of file names other than the final one.

fari35

@JonB I have checked that but still I'm getting the same error. I have added all the files with their code in my question. Can you please tell me what I'm doing wrong here?

Christian Ehrlicher

Please post your pro file and start over with a clean build dir

fari35

@Christian-Ehrlicher This is my pro file:

QT       += core
QT       +=network
QT       +=gui
greaterThan(QT_MAJOR_VERSION, 4): QT += widgets

CONFIG += c++11

# You can make your code fail to compile if it uses deprecated APIs.
# In order to do so, uncomment the following line.
#DEFINES += QT_DISABLE_DEPRECATED_BEFORE=0x060000    # disables all the APIs deprecated before Qt 6.0.0
TEMPLATE = app
SOURCES += \
    main.cpp \
    mainwindow.cpp\
    myserver.cpp
    mythread.cpp

HEADERS += \
    mainwindow.h\
    myserver.h
    mythread.h

FORMS += \
    mainwindow.ui

# Default rules for deployment.
qnx: target.path = /tmp/$${TARGET}/bin
else: unix:!android: target.path = /opt/$${TARGET}/bin
!isEmpty(target.path): INSTALLS += target

Christian Ehrlicher

You did notice what @JonB and I told you? You forgot to add the \ ...

fari35

@Christian-Ehrlicher @JonB yes Now its working but when I'm trying to create an object of MainWindow class in server.h class so I'm not able to create that. Cany you please tell me how can I make the object of MainWindow class?
server.h:

#ifndef SERVER_H
#define SERVER_H
#include <QStringList>
#include <QTcpServer>
#include "mainwindow.h"
class server : public QTcpServer
{
    Q_OBJECT

public:
    server(QObject *parent = nullptr);
    QTcpServer *tcpServer;
    
protected:
    void incomingConnection(qintptr socketDescriptor) override;

private:
    QStringList fortunes;
    MainWindow uicopy;
    
};
#endif // SERVER_H

JonB

@fari35
You make a MainWindow object/instance by MainWindow instance or MainWindow *istance = new MainWindow.

when I'm trying to create an object of MainWindow class in server.h class

You absolutely do not want to create, or reference, any MainWindow class/object, or for that matter any UI object, in your server.h/.cpp files, which should solely work on QTcp... stuff! And nor should it attempt to #include "mainwindow.h"....

You need to learn to keep your classes separate, each one only doing what it needs for its own specialized functionality.

If, say, you do have a QMainWindow in an application using QTcpServer, mainwindow can know about server, but not the other way round. MainWindow can call methods in QTcpServer, but not the other way round. Or, they can use signals/slots if required to communicate.