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Sending Data from Client to Server

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  • E ELIF

    @jsulm said in Sending Data from Client to Server:

    Your server code is wrong

    Which one ? would yo show wrong codes ?
    I understand somehow.

    Thank you.

    jsulmJ Offline
    jsulmJ Offline
    jsulm
    Lifetime Qt Champion
    wrote on last edited by jsulm
    #9

    @ELIF said in Sending Data from Client to Server:

    Which one ? would yo show wrong codes ?

    I already said what is wrong: "You need to connect a slot to readyRead signal from clientConnection!"
    Also comment from @KroMignon is correct: it makes no sense to subclass QTcpServer and then add a QTcpServer member variable...

    https://forum.qt.io/topic/113070/qt-code-of-conduct

    1 Reply Last reply
    0
    • jsulmJ jsulm

      @star673 But what exactly does not work?
      Can your client connect to the server?
      Do you see incoming connection on the server?

      S Offline
      S Offline
      star673
      wrote on last edited by
      #10

      I got an output in server side is like:
      -------NEW CONNECTION SLOT--------
      Press <RETURN> to close this window...

      Inclient side is the oput like:
      QObject::connect: No such slot QTcpSocket::displayError(QAbstractSocket::SocketError) in ../ClientConsole/client.cpp:7
      INSIDe sendMessageToServer

      I have changed the server.cpp is like below. Like you said, I have used clientConnection object for readyRead slot. The connection has accomplished but I couldnt get the data.

      #include "server.h"
      
      Server::Server(QObject *parent) : QObject(parent)
      {
          tcpServer = new QTcpServer();
           connect(tcpServer,&QTcpServer::newConnection,this,&Server::newConnection);
           initServer();
      }
      
      void Server::incomingConnection(int socketfd){
          clientConnection=new QTcpSocket(this);
          clientConnection = tcpServer->nextPendingConnection();
           connect(clientConnection, &QAbstractSocket::disconnected,
                   clientConnection, &QObject::deleteLater);
      //    client->setSocketDescriptor(socketfd);
      //    clients.insert(client);
      
          qDebug() << "New client from: " << clientConnection->peerAddress().toString();
      
          connect(clientConnection,SIGNAL(readyRead()),this,SLOT(readyRead()));
          connect(clientConnection,SIGNAL(disconnected()),this,SLOT(disconnected()));
      }
      
      void Server::newConnection(){
          qDebug() << "-------NEW CONNECTION SLOT--------";
      
      
      
           clientConnection->write("ABCDE");
           //clientConnection->disconnectFromHost();
      }
      
      
      void Server::readyRead(){
         qDebug() << "|||||||||||READYREAD SLOT--------";
          qDebug() << clientConnection->readAll();
      }
      
      void Server::disconnected(){
          qDebug() << "//////////DISCONNECTED CONNECTION SLOT--------";
      }
      
      void Server::initServer(){
      
      if (!tcpServer->listen(QHostAddress::Any,45442)) {
          qDebug() << "AAAA";
          qDebug() << tcpServer->errorString();
      
      }
      }
      
      
      JonBJ 1 Reply Last reply
      0
      • S star673

        I got an output in server side is like:
        -------NEW CONNECTION SLOT--------
        Press <RETURN> to close this window...

        Inclient side is the oput like:
        QObject::connect: No such slot QTcpSocket::displayError(QAbstractSocket::SocketError) in ../ClientConsole/client.cpp:7
        INSIDe sendMessageToServer

        I have changed the server.cpp is like below. Like you said, I have used clientConnection object for readyRead slot. The connection has accomplished but I couldnt get the data.

        #include "server.h"
        
        Server::Server(QObject *parent) : QObject(parent)
        {
            tcpServer = new QTcpServer();
             connect(tcpServer,&QTcpServer::newConnection,this,&Server::newConnection);
             initServer();
        }
        
        void Server::incomingConnection(int socketfd){
            clientConnection=new QTcpSocket(this);
            clientConnection = tcpServer->nextPendingConnection();
             connect(clientConnection, &QAbstractSocket::disconnected,
                     clientConnection, &QObject::deleteLater);
        //    client->setSocketDescriptor(socketfd);
        //    clients.insert(client);
        
            qDebug() << "New client from: " << clientConnection->peerAddress().toString();
        
            connect(clientConnection,SIGNAL(readyRead()),this,SLOT(readyRead()));
            connect(clientConnection,SIGNAL(disconnected()),this,SLOT(disconnected()));
        }
        
        void Server::newConnection(){
            qDebug() << "-------NEW CONNECTION SLOT--------";
        
        
        
             clientConnection->write("ABCDE");
             //clientConnection->disconnectFromHost();
        }
        
        
        void Server::readyRead(){
           qDebug() << "|||||||||||READYREAD SLOT--------";
            qDebug() << clientConnection->readAll();
        }
        
        void Server::disconnected(){
            qDebug() << "//////////DISCONNECTED CONNECTION SLOT--------";
        }
        
        void Server::initServer(){
        
        if (!tcpServer->listen(QHostAddress::Any,45442)) {
            qDebug() << "AAAA";
            qDebug() << tcpServer->errorString();
        
        }
        }
        
        
        JonBJ Offline
        JonBJ Offline
        JonB
        wrote on last edited by JonB
        #11

        @star673 said in Sending Data from Client to Server:

        clientConnection=new QTcpSocket(this);
        clientConnection = tcpServer->nextPendingConnection();
        

        Why do you have that first line here? All it does is leak a new QTcpSocket.

        The connection has accomplished but I couldnt get the data.

        Is your Server::readyRead() called at all?

        Inclient side is the oput like:
        QObject::connect: No such slot QTcpSocket::displayError(QAbstractSocket::SocketError) in ../ClientConsole/client.cpp:7
        INSIDe sendMessageToServer

        Then you have an error in client.cpp, which has nothing to do with the server code you are showing....

        connect(tcpSocket,SIGNAL(error(QAbstractSocket::SocketError)),this,SLOT(displayError(QAbstractSocket::SocketError)));
        connect(tcpSocket, &QTcpSocket::connected, this, &Client::sendMessageToServer);
        

        You would not get runtime errors if you made all your connections use the new style connect syntax, like the second line here. Get rid of all your SIGNAL/SLOT() macro connections, everywhere, and see where you are.

        Press <RETURN> to close this window...

        This looks like the server program has exited? Use a debugger/debug statements to trace what is happening in the server.

        S JonBJ 3 Replies Last reply
        1
        • JonBJ JonB

          @star673 said in Sending Data from Client to Server:

          clientConnection=new QTcpSocket(this);
          clientConnection = tcpServer->nextPendingConnection();
          

          Why do you have that first line here? All it does is leak a new QTcpSocket.

          The connection has accomplished but I couldnt get the data.

          Is your Server::readyRead() called at all?

          Inclient side is the oput like:
          QObject::connect: No such slot QTcpSocket::displayError(QAbstractSocket::SocketError) in ../ClientConsole/client.cpp:7
          INSIDe sendMessageToServer

          Then you have an error in client.cpp, which has nothing to do with the server code you are showing....

          connect(tcpSocket,SIGNAL(error(QAbstractSocket::SocketError)),this,SLOT(displayError(QAbstractSocket::SocketError)));
          connect(tcpSocket, &QTcpSocket::connected, this, &Client::sendMessageToServer);
          

          You would not get runtime errors if you made all your connections use the new style connect syntax, like the second line here. Get rid of all your SIGNAL/SLOT() macro connections, everywhere, and see where you are.

          Press <RETURN> to close this window...

          This looks like the server program has exited? Use a debugger/debug statements to trace what is happening in the server.

          S Offline
          S Offline
          star673
          wrote on last edited by
          #12

          @JonB
          I have commented this line.

          clientConnection=new QTcpSocket(this);
          

          When I commented the connect functions server application did not crashed. It seems the problem is related with these lines. Did I use them worng?

              connect(clientConnection,SIGNAL(readyRead()),this,SLOT(readyRead()));
              connect(clientConnection,SIGNAL(disconnected()),this,SLOT(disconnected()));
          
          1 Reply Last reply
          0
          • JonBJ JonB

            @star673 said in Sending Data from Client to Server:

            clientConnection=new QTcpSocket(this);
            clientConnection = tcpServer->nextPendingConnection();
            

            Why do you have that first line here? All it does is leak a new QTcpSocket.

            The connection has accomplished but I couldnt get the data.

            Is your Server::readyRead() called at all?

            Inclient side is the oput like:
            QObject::connect: No such slot QTcpSocket::displayError(QAbstractSocket::SocketError) in ../ClientConsole/client.cpp:7
            INSIDe sendMessageToServer

            Then you have an error in client.cpp, which has nothing to do with the server code you are showing....

            connect(tcpSocket,SIGNAL(error(QAbstractSocket::SocketError)),this,SLOT(displayError(QAbstractSocket::SocketError)));
            connect(tcpSocket, &QTcpSocket::connected, this, &Client::sendMessageToServer);
            

            You would not get runtime errors if you made all your connections use the new style connect syntax, like the second line here. Get rid of all your SIGNAL/SLOT() macro connections, everywhere, and see where you are.

            Press <RETURN> to close this window...

            This looks like the server program has exited? Use a debugger/debug statements to trace what is happening in the server.

            JonBJ Offline
            JonBJ Offline
            JonB
            wrote on last edited by JonB
            #13

            @star673

            @JonB said in Sending Data from Client to Server:

            Get rid of all your SIGNAL/SLOT() macro connections, everywhere, and see where you are.

            Come back when you have done that....

            [I can see one thing which looks wrong at both your client & server sides, let's see whether it gets picked up. In any case, and especially with the trouble you are having, you really do need to change over to new style connects for all your code.]

            H S 2 Replies Last reply
            0
            • JonBJ JonB

              @star673

              @JonB said in Sending Data from Client to Server:

              Get rid of all your SIGNAL/SLOT() macro connections, everywhere, and see where you are.

              Come back when you have done that....

              [I can see one thing which looks wrong at both your client & server sides, let's see whether it gets picked up. In any case, and especially with the trouble you are having, you really do need to change over to new style connects for all your code.]

              H Offline
              H Offline
              hix_boz
              wrote on last edited by
              #14
              This post is deleted!
              1 Reply Last reply
              0
              • JonBJ JonB

                @star673

                @JonB said in Sending Data from Client to Server:

                Get rid of all your SIGNAL/SLOT() macro connections, everywhere, and see where you are.

                Come back when you have done that....

                [I can see one thing which looks wrong at both your client & server sides, let's see whether it gets picked up. In any case, and especially with the trouble you are having, you really do need to change over to new style connects for all your code.]

                S Offline
                S Offline
                star673
                wrote on last edited by
                #15

                @JonB

                How to change this line?

                connect(tcpSocket,SIGNAL(error(QAbstractSocket::SocketError)),this,SLOT(displayError(QAbstractSocket::SocketError)));
                
                JonBJ Christian EhrlicherC 2 Replies Last reply
                0
                • S star673

                  @JonB

                  How to change this line?

                  connect(tcpSocket,SIGNAL(error(QAbstractSocket::SocketError)),this,SLOT(displayError(QAbstractSocket::SocketError)));
                  
                  JonBJ Offline
                  JonBJ Offline
                  JonB
                  wrote on last edited by JonB
                  #16

                  @star673

                  connect(tcpSocket, &QTcpSocket::error, this, &ThisClass::displayError);
                  

                  UPDATE
                  As per @Christian-Ehrlicher's link below, the QTcpSocket::error signal is overloaded in this class and you will actually need the QOverload<QAbstractSocket::SocketError>::of() shown there. You will also note that this method is now obsolete and you are advised to "Use errorOccurred() instead", which will look simpler.

                  1 Reply Last reply
                  0
                  • S star673

                    @JonB

                    How to change this line?

                    connect(tcpSocket,SIGNAL(error(QAbstractSocket::SocketError)),this,SLOT(displayError(QAbstractSocket::SocketError)));
                    
                    Christian EhrlicherC Offline
                    Christian EhrlicherC Offline
                    Christian Ehrlicher
                    Lifetime Qt Champion
                    wrote on last edited by
                    #17

                    @star673 said in Sending Data from Client to Server:

                    How to change this line?

                    By looking into the documentation... reading seems to be very hard.

                    Qt Online Installer direct download: https://download.qt.io/official_releases/online_installers/
                    Visit the Qt Academy at https://academy.qt.io/catalog

                    1 Reply Last reply
                    2
                    • JonBJ JonB

                      @star673 said in Sending Data from Client to Server:

                      clientConnection=new QTcpSocket(this);
                      clientConnection = tcpServer->nextPendingConnection();
                      

                      Why do you have that first line here? All it does is leak a new QTcpSocket.

                      The connection has accomplished but I couldnt get the data.

                      Is your Server::readyRead() called at all?

                      Inclient side is the oput like:
                      QObject::connect: No such slot QTcpSocket::displayError(QAbstractSocket::SocketError) in ../ClientConsole/client.cpp:7
                      INSIDe sendMessageToServer

                      Then you have an error in client.cpp, which has nothing to do with the server code you are showing....

                      connect(tcpSocket,SIGNAL(error(QAbstractSocket::SocketError)),this,SLOT(displayError(QAbstractSocket::SocketError)));
                      connect(tcpSocket, &QTcpSocket::connected, this, &Client::sendMessageToServer);
                      

                      You would not get runtime errors if you made all your connections use the new style connect syntax, like the second line here. Get rid of all your SIGNAL/SLOT() macro connections, everywhere, and see where you are.

                      Press <RETURN> to close this window...

                      This looks like the server program has exited? Use a debugger/debug statements to trace what is happening in the server.

                      S Offline
                      S Offline
                      star673
                      wrote on last edited by star673
                      #18

                      @JonB

                      I hav changed the error slot like below.

                          connect(tcpSocket, QOverload<QAbstractSocket::SocketError>::of(&QAbstractSocket::error),
                              [=](QAbstractSocket::SocketError socketError){
                      
                              switch(socketError){
                              case QAbstractSocket::RemoteHostClosedError:
                                  break;
                      
                              case QAbstractSocket::HostNotFoundError:
                                  qDebug() << "HostNotFoundError. Connection was refused. Server is not working";
                                  break;
                      
                      
                              case QAbstractSocket::ConnectionRefusedError:
                                  qDebug() << "ConnectionRefusedError. Client. The host was not found";
                                  break;
                      
                              default:
                                  qDebug() << "ErrorString : " << tcpSocket->errorString();
                            }
                      
                      
                          });
                      

                      Now I dont have any runtime error like before. The connected signal is emitted by the client but than nothing happens. I could not read from client, too. There is no printed socket error. My incoming connection function like below.

                      void Server::incomingConnection(int socketfd){
                         // clientConnection=new QTcpSocket(this);
                          clientConnection = tcpServer->nextPendingConnection();
                           connect(clientConnection, &QAbstractSocket::disconnected,
                                   clientConnection, &QObject::deleteLater);
                      
                      //    client->setSocketDescriptor(socketfd);
                      //    clients.insert(client);
                      
                          qDebug() << "New client from: " << clientConnection->peerAddress().toString();
                      

                      There is no print which starting "New client from" so it seems something wron with server side.

                      1 Reply Last reply
                      0
                      • Christian EhrlicherC Offline
                        Christian EhrlicherC Offline
                        Christian Ehrlicher
                        Lifetime Qt Champion
                        wrote on last edited by
                        #19

                        Please show your actual code with the new signal/slot syntax.

                        Qt Online Installer direct download: https://download.qt.io/official_releases/online_installers/
                        Visit the Qt Academy at https://academy.qt.io/catalog

                        S 1 Reply Last reply
                        0
                        • Christian EhrlicherC Christian Ehrlicher

                          Please show your actual code with the new signal/slot syntax.

                          S Offline
                          S Offline
                          star673
                          wrote on last edited by
                          #20

                          @Christian-Ehrlicher

                          My server.cpp file is,

                          #include "server.h"
                          
                          Server::Server(QObject *parent) : QObject(parent)
                          {
                              tcpServer = new QTcpServer();
                               connect(tcpServer,&QTcpServer::newConnection,this,&Server::newConnection);
                               initServer();
                          }
                          
                          void Server::incomingConnection(int socketfd){
                             // clientConnection=new QTcpSocket(this);
                              clientConnection = tcpServer->nextPendingConnection();
                               connect(clientConnection, &QAbstractSocket::disconnected,
                                       clientConnection, &QObject::deleteLater);
                          
                          //    client->setSocketDescriptor(socketfd);
                          //    clients.insert(client);
                          
                              qDebug() << "New client from: " << clientConnection->peerAddress().toString();
                          
                              connect(clientConnection,SIGNAL(readyRead()),this,SLOT(readyRead()));
                              connect(clientConnection,SIGNAL(disconnected()),this,SLOT(disconnected()));
                          }
                          
                          void Server::newConnection(){
                              qDebug() << "-------NEW CONNECTION SLOT--------";
                          
                          //    QByteArray block;
                          //    QDataStream out(&block, QIODevice::ReadWrite);
                          //    out.setVersion(QDataStream::Qt_5_9);
                          
                          //    out << "ABCderfHt";
                          
                          
                               clientConnection->write("ABCDE");
                               //clientConnection->disconnectFromHost();
                          }
                          
                          
                          void Server::readyRead(){
                             qDebug() << "|||||||||||READYREAD SLOT--------";
                          
                          
                          
                              qDebug() << clientConnection->readAll();
                          }
                          
                          void Server::disconnected(){
                              qDebug() << "//////////DISCONNECTED CONNECTION SLOT--------";
                          }
                          
                          void Server::initServer(){
                          
                              if (!tcpServer->listen(QHostAddress::Any,45442)) {
                                  qDebug() << tcpServer->errorString();
                          
                              }
                          
                              else{
                                  qDebug() << "Listening";
                              }
                          }
                          
                          

                          My server.h file is,

                          #ifndef SERVER_H
                          #define SERVER_H
                          
                          
                          #include <QObject>
                          #include <QTcpServer>
                          #include <QTcpSocket>
                          #include <QDebug>
                          #include <QDataStream>
                          #include <QByteArray>
                          #include <QNetworkInterface>
                          #include <QAbstractSocket>
                          
                          
                          
                          
                          
                          class Server : public QObject
                          {
                          
                              Q_OBJECT
                          
                          public:
                              explicit Server(QObject *parent = nullptr);
                              QTcpServer *tcpServer = nullptr;
                              void initServer();
                              QTcpSocket *clientConnection;
                             // QDataStream out;
                          
                          
                          
                          
                          
                          protected:
                              void incomingConnection(int socketfd);
                          
                          public slots:
                              void newConnection();
                              void readyRead();
                              void disconnected();
                          private:
                              QSet<QTcpSocket*> clients;
                          };
                          
                          #endif // SERVER_H
                          
                          

                          The main.cpp on the server side,

                          #include <QCoreApplication>
                          #include "server.h"
                          
                          int main(int argc, char *argv[])
                          {
                              QCoreApplication a(argc, argv);
                          
                              Server server;
                          
                              return a.exec();
                          }
                          
                          

                          My client.cpp is,

                          #include "client.h"
                          
                          Client::Client()
                          {
                              tcpSocket = new QTcpSocket();
                              tcpSocket->connectToHost(QHostAddress::LocalHost,45442);
                              //connect(tcpSocket,SIGNAL(error(QAbstractSocket::SocketError)),this,SLOT(displayError(QAbstractSocket::SocketError)));
                             // connect(tcpSocket,QOverload<QAbstractSocket::SocketError>::of(error),this,&Client::displayError);
                              connect(tcpSocket, QOverload<QAbstractSocket::SocketError>::of(&QAbstractSocket::error),
                                  [=](QAbstractSocket::SocketError socketError){
                          
                                  switch(socketError){
                                  case QAbstractSocket::RemoteHostClosedError:
                                      break;
                          
                                  case QAbstractSocket::HostNotFoundError:
                                      qDebug() << "HostNotFoundError. Connection was refused. Server is not working";
                                      break;
                          
                          
                                  case QAbstractSocket::ConnectionRefusedError:
                                      qDebug() << "ConnectionRefusedError. Client. The host was not found";
                                      break;
                          
                                  default:
                                      qDebug() << "ErrorString : " << tcpSocket->errorString();
                                }
                          
                          
                              });
                          
                          
                              connect(tcpSocket, &QTcpSocket::connected, this, &Client::sendMessageToServer);
                              connect(tcpSocket,&QTcpSocket::readyRead, this, &Client::readyRead);
                          
                          }
                          
                          void Client::displayError(QAbstractSocket::SocketError socketError){
                          
                              switch(socketError){
                              case QAbstractSocket::RemoteHostClosedError:
                                  break;
                          
                              case QAbstractSocket::HostNotFoundError:
                                  qDebug() << "HostNotFoundError. Connection was refused. Server is not working";
                                  break;
                          
                          
                              case QAbstractSocket::ConnectionRefusedError:
                                  qDebug() << "ConnectionRefusedError. Client. The host was not found";
                                  break;
                          
                              default:
                                  qDebug() << "ErrorString : " << tcpSocket->errorString();
                            }
                          
                          }
                          
                          void Client::sendMessageToServer(){
                              qDebug() << "INSIDe sendMessageToServer";
                              //tcpSocket->waitForReadyRead();
                              qDebug() << tcpSocket->canReadLine() << tcpSocket->readAll();
                              tcpSocket->write("MessageFromClient");
                              //tcpSocket->flush();
                          
                          }
                          
                          void Client::readyRead(){
                              qDebug() << "///READYREAD SLOT///";
                          
                          //    in.startTransaction();
                          
                          //    QString nextFortune;
                          //    in >> nextFortune;
                          
                          //    if (!in.commitTransaction())
                          //        return;
                              qDebug() << tcpSocket->readAll();
                          
                          
                          }
                          
                          
                          

                          My client.h is,

                          #ifndef CLIENT_H
                          #define CLIENT_H
                          
                          #include <QObject>
                          #include <QTcpServer>
                          #include <QTcpSocket>
                          #include <QDebug>
                          #include <QDataStream>
                          #include <QByteArray>
                          #include <QNetworkInterface>
                          #include <QAbstractSocket>
                          
                          class Client  : public QTcpSocket
                          {
                          public:
                              Client();
                              QTcpSocket *tcpSocket = nullptr;
                               QDataStream in;
                          
                          public slots:
                              void displayError(QAbstractSocket::SocketError socketError);
                              void sendMessageToServer();
                              void readyRead();
                          };
                          
                          #endif // CLIENT_H
                          
                          

                          The main.cpp on the client side is,

                          #include <QCoreApplication>
                          #include "client.h"
                          
                          int main(int argc, char *argv[])
                          {
                              QCoreApplication a(argc, argv);
                              Client client;
                          
                              return a.exec();
                          }
                          
                          
                          jsulmJ 1 Reply Last reply
                          0
                          • S star673

                            @Christian-Ehrlicher

                            My server.cpp file is,

                            #include "server.h"
                            
                            Server::Server(QObject *parent) : QObject(parent)
                            {
                                tcpServer = new QTcpServer();
                                 connect(tcpServer,&QTcpServer::newConnection,this,&Server::newConnection);
                                 initServer();
                            }
                            
                            void Server::incomingConnection(int socketfd){
                               // clientConnection=new QTcpSocket(this);
                                clientConnection = tcpServer->nextPendingConnection();
                                 connect(clientConnection, &QAbstractSocket::disconnected,
                                         clientConnection, &QObject::deleteLater);
                            
                            //    client->setSocketDescriptor(socketfd);
                            //    clients.insert(client);
                            
                                qDebug() << "New client from: " << clientConnection->peerAddress().toString();
                            
                                connect(clientConnection,SIGNAL(readyRead()),this,SLOT(readyRead()));
                                connect(clientConnection,SIGNAL(disconnected()),this,SLOT(disconnected()));
                            }
                            
                            void Server::newConnection(){
                                qDebug() << "-------NEW CONNECTION SLOT--------";
                            
                            //    QByteArray block;
                            //    QDataStream out(&block, QIODevice::ReadWrite);
                            //    out.setVersion(QDataStream::Qt_5_9);
                            
                            //    out << "ABCderfHt";
                            
                            
                                 clientConnection->write("ABCDE");
                                 //clientConnection->disconnectFromHost();
                            }
                            
                            
                            void Server::readyRead(){
                               qDebug() << "|||||||||||READYREAD SLOT--------";
                            
                            
                            
                                qDebug() << clientConnection->readAll();
                            }
                            
                            void Server::disconnected(){
                                qDebug() << "//////////DISCONNECTED CONNECTION SLOT--------";
                            }
                            
                            void Server::initServer(){
                            
                                if (!tcpServer->listen(QHostAddress::Any,45442)) {
                                    qDebug() << tcpServer->errorString();
                            
                                }
                            
                                else{
                                    qDebug() << "Listening";
                                }
                            }
                            
                            

                            My server.h file is,

                            #ifndef SERVER_H
                            #define SERVER_H
                            
                            
                            #include <QObject>
                            #include <QTcpServer>
                            #include <QTcpSocket>
                            #include <QDebug>
                            #include <QDataStream>
                            #include <QByteArray>
                            #include <QNetworkInterface>
                            #include <QAbstractSocket>
                            
                            
                            
                            
                            
                            class Server : public QObject
                            {
                            
                                Q_OBJECT
                            
                            public:
                                explicit Server(QObject *parent = nullptr);
                                QTcpServer *tcpServer = nullptr;
                                void initServer();
                                QTcpSocket *clientConnection;
                               // QDataStream out;
                            
                            
                            
                            
                            
                            protected:
                                void incomingConnection(int socketfd);
                            
                            public slots:
                                void newConnection();
                                void readyRead();
                                void disconnected();
                            private:
                                QSet<QTcpSocket*> clients;
                            };
                            
                            #endif // SERVER_H
                            
                            

                            The main.cpp on the server side,

                            #include <QCoreApplication>
                            #include "server.h"
                            
                            int main(int argc, char *argv[])
                            {
                                QCoreApplication a(argc, argv);
                            
                                Server server;
                            
                                return a.exec();
                            }
                            
                            

                            My client.cpp is,

                            #include "client.h"
                            
                            Client::Client()
                            {
                                tcpSocket = new QTcpSocket();
                                tcpSocket->connectToHost(QHostAddress::LocalHost,45442);
                                //connect(tcpSocket,SIGNAL(error(QAbstractSocket::SocketError)),this,SLOT(displayError(QAbstractSocket::SocketError)));
                               // connect(tcpSocket,QOverload<QAbstractSocket::SocketError>::of(error),this,&Client::displayError);
                                connect(tcpSocket, QOverload<QAbstractSocket::SocketError>::of(&QAbstractSocket::error),
                                    [=](QAbstractSocket::SocketError socketError){
                            
                                    switch(socketError){
                                    case QAbstractSocket::RemoteHostClosedError:
                                        break;
                            
                                    case QAbstractSocket::HostNotFoundError:
                                        qDebug() << "HostNotFoundError. Connection was refused. Server is not working";
                                        break;
                            
                            
                                    case QAbstractSocket::ConnectionRefusedError:
                                        qDebug() << "ConnectionRefusedError. Client. The host was not found";
                                        break;
                            
                                    default:
                                        qDebug() << "ErrorString : " << tcpSocket->errorString();
                                  }
                            
                            
                                });
                            
                            
                                connect(tcpSocket, &QTcpSocket::connected, this, &Client::sendMessageToServer);
                                connect(tcpSocket,&QTcpSocket::readyRead, this, &Client::readyRead);
                            
                            }
                            
                            void Client::displayError(QAbstractSocket::SocketError socketError){
                            
                                switch(socketError){
                                case QAbstractSocket::RemoteHostClosedError:
                                    break;
                            
                                case QAbstractSocket::HostNotFoundError:
                                    qDebug() << "HostNotFoundError. Connection was refused. Server is not working";
                                    break;
                            
                            
                                case QAbstractSocket::ConnectionRefusedError:
                                    qDebug() << "ConnectionRefusedError. Client. The host was not found";
                                    break;
                            
                                default:
                                    qDebug() << "ErrorString : " << tcpSocket->errorString();
                              }
                            
                            }
                            
                            void Client::sendMessageToServer(){
                                qDebug() << "INSIDe sendMessageToServer";
                                //tcpSocket->waitForReadyRead();
                                qDebug() << tcpSocket->canReadLine() << tcpSocket->readAll();
                                tcpSocket->write("MessageFromClient");
                                //tcpSocket->flush();
                            
                            }
                            
                            void Client::readyRead(){
                                qDebug() << "///READYREAD SLOT///";
                            
                            //    in.startTransaction();
                            
                            //    QString nextFortune;
                            //    in >> nextFortune;
                            
                            //    if (!in.commitTransaction())
                            //        return;
                                qDebug() << tcpSocket->readAll();
                            
                            
                            }
                            
                            
                            

                            My client.h is,

                            #ifndef CLIENT_H
                            #define CLIENT_H
                            
                            #include <QObject>
                            #include <QTcpServer>
                            #include <QTcpSocket>
                            #include <QDebug>
                            #include <QDataStream>
                            #include <QByteArray>
                            #include <QNetworkInterface>
                            #include <QAbstractSocket>
                            
                            class Client  : public QTcpSocket
                            {
                            public:
                                Client();
                                QTcpSocket *tcpSocket = nullptr;
                                 QDataStream in;
                            
                            public slots:
                                void displayError(QAbstractSocket::SocketError socketError);
                                void sendMessageToServer();
                                void readyRead();
                            };
                            
                            #endif // CLIENT_H
                            
                            

                            The main.cpp on the client side is,

                            #include <QCoreApplication>
                            #include "client.h"
                            
                            int main(int argc, char *argv[])
                            {
                                QCoreApplication a(argc, argv);
                                Client client;
                            
                                return a.exec();
                            }
                            
                            
                            jsulmJ Offline
                            jsulmJ Offline
                            jsulm
                            Lifetime Qt Champion
                            wrote on last edited by
                            #21

                            @star673 said in Sending Data from Client to Server:

                            void Server::incomingConnection(int socketfd){

                            If you check the documentation you will see that incomingConnection is a protected virtual method in QTcpServer. If you want to use it you have to subclass QTcpServer and override it. But if you use QTcpServer::newConnection signal there is no need for incomingConnection - simply move the code from your incomingConnection to newConnection.

                            https://forum.qt.io/topic/113070/qt-code-of-conduct

                            S 1 Reply Last reply
                            1
                            • jsulmJ jsulm

                              @star673 said in Sending Data from Client to Server:

                              void Server::incomingConnection(int socketfd){

                              If you check the documentation you will see that incomingConnection is a protected virtual method in QTcpServer. If you want to use it you have to subclass QTcpServer and override it. But if you use QTcpServer::newConnection signal there is no need for incomingConnection - simply move the code from your incomingConnection to newConnection.

                              S Offline
                              S Offline
                              star673
                              wrote on last edited by
                              #22

                              @jsulm

                              Thank you for helping, it worked like below.

                              #include "server.h"
                              
                              Server::Server(QObject *parent) : QObject(parent)
                              {
                              
                                  tcpServer = new QTcpServer();
                                   connect(tcpServer,&QTcpServer::newConnection,this,&Server::newConnection);
                                   initServer();
                              
                                  timer = new QTimer(this);
                              }
                              
                              
                              
                              
                              void Server::newConnection(){
                                  qDebug() << "-------NEW CONNECTION SLOT--------";
                              
                                 
                                   clientConnection = tcpServer->nextPendingConnection();
                                    connect(clientConnection, &QAbstractSocket::disconnected,
                                            clientConnection, &QObject::deleteLater);
                              
                              
                                   qDebug() << "New client from: " << clientConnection->peerAddress().toString();
                              
                              
                                   connect(clientConnection,&QAbstractSocket::readyRead,this,&Server::readyRead);
                                   connect(clientConnection,&QAbstractSocket::disconnected,this,&Server::disconnected);
                              
                              
                              
                                   clientConnection->write("ABCDEFFGHJKL");
                                   
                                   connect(timer,&QTimer::timeout,this,&Server::TimerSlot);
                                   timer->start(1000);
                              }
                              
                              
                              void Server::readyRead(){
                                 qDebug() << "|||||||||||READYREAD SLOT--------";
                                 qDebug() << "||||||||" << clientConnection->readAll();
                              
                              }
                              
                              
                              
                              void Server::disconnected(){
                                  qDebug() << "//////////DISCONNECTED CONNECTION SLOT--------";
                              }
                              
                              void Server::initServer(){
                              
                                  if (!tcpServer->listen(QHostAddress::Any,45442)) {
                                      qDebug() << tcpServer->errorString();
                              
                                  }
                              
                                  else{
                                      qDebug() << "Listening";
                              
                              
                                  }
                              }
                              
                              
                              void Server::TimerSlot(){
                              
                                  clientConnection->write("ABCDEFFGHJKL");
                              
                              }
                              
                              

                              The client side is,

                              #include "client.h"
                              
                              Client::Client()
                              {
                                  tcpSocket = new QTcpSocket();
                                  tcpSocket->connectToHost(QHostAddress::LocalHost,45442);
                              
                                  connect(tcpSocket, QOverload<QAbstractSocket::SocketError>::of(&QAbstractSocket::error),
                                      [=](QAbstractSocket::SocketError socketError){
                              
                                      switch(socketError){
                                      case QAbstractSocket::RemoteHostClosedError:
                                          break;
                              
                                      case QAbstractSocket::HostNotFoundError:
                                          qDebug() << "HostNotFoundError. Connection was refused. Server is not working";
                                          break;
                              
                              
                                      case QAbstractSocket::ConnectionRefusedError:
                                          qDebug() << "ConnectionRefusedError. Client. The host was not found";
                                          break;
                              
                                      default:
                                          qDebug() << "ErrorString : " << tcpSocket->errorString();
                                    }
                              
                              
                                  });
                              
                              
                                  connect(tcpSocket, &QTcpSocket::connected, this, &Client::sendMessageToServer);
                                  connect(tcpSocket,&QTcpSocket::readyRead, this, &Client::readyRead);
                              
                              
                                  timer = new QTimer(this);
                              
                              }
                              
                              void Client::displayError(QAbstractSocket::SocketError socketError){
                              
                                  switch(socketError){
                                  case QAbstractSocket::RemoteHostClosedError:
                                      break;
                              
                                  case QAbstractSocket::HostNotFoundError:
                                      qDebug() << "HostNotFoundError. Connection was refused. Server is not working";
                                      break;
                              
                              
                                  case QAbstractSocket::ConnectionRefusedError:
                                      qDebug() << "ConnectionRefusedError. Client. The host was not found";
                                      break;
                              
                                  default:
                                      qDebug() << "ErrorString : " << tcpSocket->errorString();
                                }
                              
                              }
                              
                              void Client::sendMessageToServer(){
                                  qDebug() << "INSIDe sendMessageToServer";
                                  qDebug() << tcpSocket->canReadLine() << tcpSocket->readAll();
                                  tcpSocket->write("MessageFromClient");
                                 
                                  connect(timer,&QTimer::timeout,this,&Client::TimerSlotClient);
                                  timer->start(1000);
                              }
                              
                              void Client::readyRead(){
                                  qDebug() << "///READYREAD SLOT///";
                                  qDebug() << tcpSocket->readAll();
                              }
                              
                              void Client::TimerSlotClient(){
                                     tcpSocket->write("MessageFromClient");
                              }
                              
                              
                              
                              1 Reply Last reply
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