How to get the system date and time using socket programming

Question

I sending simple message from client to the server here and its working fine, But what if client wants to fetch the server system date and time.

Client

mainwindow.cpp

Client::Client(QObject* parent): QObject(parent)
{
    connect(&client, SIGNAL(connected()),
    this, SLOT(startTransfer()));
}

Client::~Client()
{
    client.close();
}

void Client::start(QString address, quint16 port)
{
    QHostAddress addr(address);
    client.connectToHost(addr, port);
}

void Client::startTransfer()
{
    client.write("Hi server this is client", 80);
}

I don't have any idea how to do that as i am new in QT c++. thank you so much in advance ...

server

main.cpp

    #include "mainwindow.h"
  #include <QApplication>



  int main(int argc, char** argv)
  {
    QApplication app(argc, argv);
    Server server;
    return app.exec();
  }

Answer 1

I think this part of code you released is client side , you should provide a request from client to server like common hand shaking.

In server side you provide the date/time in a specific format that client can recognize it and send it. to seem more on client/server programming check Local Fortune Client and Local Fortune Server examples.

here is your client side simple example:

void Client::startTransfer()
{
    client.write("Hi server send time");
    client.flush();
    client.waitForBytesWritten(300);
}

and you server side example :

on newconnection slot in server connect client data to a slot like client message.

void ServerSocket::newConnection()
{
    QTcpSocket *clientsocket = mserver->nextPendingConnection();
    connect(clientsocket , SIGNAL(readyRead()) , this , SLOT(clientMessage()));
}

and respond it in slot client message

void ServerSocket::clientMessage()
{
    QTcpSocket* client = (QTcpSocket*)sender();
    QString  message(client->readAll());
    if (message == "Hi server send time")
    {
        client->write(QDateTime::currentDateTimeUtc().toString().toLatin1());
        client->flush();
        client->waitForBytesWritten(300);
    }
}

here is a complete code requested :

servesocket.h

#ifndef SERVERSOCKET_H
#define SERVERSOCKET_H

#include <QObject>
#include <QDebug>
#include <QTcpServer>
#include <QTcpSocket>

class ServerSocket : public QObject
{
    Q_OBJECT
public:
    explicit ServerSocket(QObject *parent = nullptr);
    QTcpServer *mserver;

signals:

public slots:

    void newConnection();
    void clientMessage();

};

#endif // SERVERSOCKET_H

serversocket.cpp

#include "serversocket.h"
#include <QDateTime>

ServerSocket::ServerSocket(QObject *parent) : QObject(parent)
{
    mserver = new QTcpServer(this);
    mserver->connect(mserver , SIGNAL(newConnection()) , this , SLOT(newConnection()));
    if(!mserver->listen(QHostAddress::Any , 1234))
    {
        qDebug() << "Server initilize failed";
    }
}

void ServerSocket::newConnection()
{
    QTcpSocket *clientsocket = mserver->nextPendingConnection();
    connect(clientsocket , SIGNAL(readyRead()) , this , SLOT(clientMessage()));
}

void ServerSocket::clientMessage()
{
    QTcpSocket* client = (QTcpSocket*)sender();
    QString  message(client->readAll());
    if (message == "Hi server send time")
    {
        client->write(QDateTime::currentDateTimeUtc().toString().toLatin1());
        client->flush();
        client->waitForBytesWritten(300);
    }
}

MainWindow header

#ifndef MAINWINDOW_H
#define MAINWINDOW_H

#include <QLineEdit>
#include <QMainWindow>
#include <QSerialPort>

#include "serversocket.h"

namespace Ui {
class MainWindow;
}

class MainWindow : public QMainWindow
{
    Q_OBJECT

public:
    explicit MainWindow(QWidget *parent = 0);//:QMainWindow(parent)
    ~MainWindow();

private slots:



private:
    Ui::MainWindow *ui;
    ServerSocket * server;

};

#endif // MAINWINDOW_H

MainWindow cpp

MainWindow::MainWindow(QWidget *parent) :
    QMainWindow(parent),
    ui(new Ui::MainWindow)
{
    ui->setupUi(this);
    server = new ServerSocket();
}

MainWindow::~MainWindow()
{
    delete ui;
}