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Sending messages from a client to server using network on the same machine

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  • SGaistS Offline
    SGaistS Offline
    SGaist
    Lifetime Qt Champion
    wrote on last edited by
    #12

    This is enough to receive data from your client and automatically delete the socket on disconnection however it will require to use the sender method to retrieve the data:

    void Server::onNewConnection()
    {
        QTcpSocket *clientConnection = tcpServer->nextPendingConnection();
        connect(clientConnection, &QAbstractSocket::disconnected,
                clientConnection, &QObject::deleteLater);
        connect(clientConnection, &QAbstractSocket::readyRead, this, &Server::processMessage);
    }
    

    The other solution would be to use a lambda rather than a slot.
    Lastly, depending on what else you want to do with the socket object, you should add a member variable to your Server class to store it, whether it's a QTcpSocket pointer or a vector of them will depend on how much connections you are going to allow to your server.

    Interested in AI ? www.idiap.ch
    Please read the Qt Code of Conduct - https://forum.qt.io/topic/113070/qt-code-of-conduct

    1 Reply Last reply
    1
    • Q Offline
      Q Offline
      qcoderpro
      wrote on last edited by qcoderpro
      #13

      The example is much harder than I thought of! :|
      I had to simplify the examples as much as possible to get the topic and can get them to work as expected. I'm sorry that I send the examples part of which may be repetitive.
      (The purpose is the same: connecting client to the server and then sending messages to it)
      client.h

      class QTcpSocket;
      
      class Client : public QObject
      {
          Q_OBJECT
      
      public:
          explicit Client(QObject *parent = nullptr);
      
      public slots:
          void sendMessage(QString, QString);
      
      private:
          QTcpSocket* tcpSocket { nullptr };
          QDataStream in;
      };
      

      client.cpp

      #include "client.h"
      #include <QtNetwork>
      
      Client::Client(QObject *parent)
          : QObject{parent}
          , tcpSocket(new QTcpSocket(this))
      {
          in.setDevice(tcpSocket);
          in.setVersion(QDataStream::Qt_4_0);
      }
      
      void Client::sendMessage(QString ip, QString port)
      {
          tcpSocket->abort();
          tcpSocket->connectToHost(ip, port.toInt());
      }
      

      main.qml

      Window {
          width: 300
          height: 200
          visible: true
          title: qsTr("Client")
          color: "lightblue"
      
          ColumnLayout {
              anchors.fill: parent
      
              TextField {
                  id: ipAddrs
              }
              TextField {
                      id: portNum
                  }
      
              RowLayout {
                  Layout.alignment: Qt.AlignBottom
      
                  TextField {
                      id: txtField
                      Layout.fillWidth: true
                  }
                  Button {
                      text: qsTr("Send")
                      onClicked:
                      myObject.sendMessage(ipAddrs.text.toString(), portNum.text.toString())
                  }
              }
          }
      
          MyObject{
              id: myObject
          }
      }
      

      server.h

      class QTcpServer;
      class QTcpSocket;
      
      class Server : public QObject
      {
          Q_OBJECT
      public:
          explicit Server(QObject *parent = nullptr);
      
      public slots:
          QString initServer();
          QString setMessage();
          void onNewConnection();
      
      private:
          QTcpServer* tcpServer { nullptr };
          QTcpSocket* tcpSocket { nullptr };
          QDataStream in;
      };
      

      server.cpp

      #include "server.h"
      #include <QtNetwork>
      #include <QtCore>
      
      Server::Server(QObject *parent)
          : QObject{parent}
          , tcpServer(new QTcpServer(this))
          , tcpSocket(new QTcpSocket(this))
      {
          initServer();
          in.setDevice(tcpSocket);
          in.setVersion(QDataStream::Qt_4_0);
          connect(tcpServer, &QTcpServer::newConnection, this, &Server::onNewConnection);
      }
      
      QString Server::initServer() {
      
          tcpServer = new QTcpServer(this);
          if(!tcpServer->listen())
              return "Server Unable to start the server: " +
                      tcpServer->errorString();
      
          QString ipAddress;
          QList<QHostAddress> ipAddressesList = QNetworkInterface::allAddresses();
      
          // use the first non-local IPv4 address
          for(int i=0; i<ipAddressesList.size(); ++i)
              if(ipAddressesList.at(i) != QHostAddress::LocalHost &&
                      ipAddressesList.at(i).toIPv4Address()) {
                  ipAddress = ipAddressesList.at(i).toString();
                  break;
              }
      
          // if we did not find one, use IPv4 localhost
          if(ipAddress.isEmpty())
              ipAddress = QHostAddress(QHostAddress::LocalHost).toString();
      
          return " The server is running on\n\n IP: " +
                  ipAddress + "\n port: " + QString::number(tcpServer->serverPort())
                  + "\n\n Run the Client example now.";
      }
      
      void Server::onNewConnection()
      {
          QTcpSocket *clientConnection = tcpServer->nextPendingConnection();
          connect(clientConnection, &QAbstractSocket::disconnected,
                  clientConnection, &QObject::deleteLater);
          connect(clientConnection, &QAbstractSocket::readyRead, this, &Server::setMessage);
      }
      
      QString Server::setMessage()
      {
          in.startTransaction();
      
          QString message;
          in >> message;
      
          if (!in.commitTransaction())
             return "commitTransaction error" ;
      
          return message;
      }
      

      main.qml

      Window {
          width: 300
          height: 200
          visible: true
          title: qsTr("Server")
          color: "lightblue"
      
          ColumnLayout {
              anchors.fill: parent
      
              Label {
                  text: myObject.initServer()
              }
      
              Label {
                  id: msgLabel
                  text: myObject.setMessage()
              }
          }
      
          MyObject{
              id: myObject
          }
      }
      

      For now I have only a question. Are the projects to this point fine? I mean I know that there may be many things to be added to them but isn't anything redundant up to here?

      Q 1 Reply Last reply
      0
      • Q qcoderpro

        The example is much harder than I thought of! :|
        I had to simplify the examples as much as possible to get the topic and can get them to work as expected. I'm sorry that I send the examples part of which may be repetitive.
        (The purpose is the same: connecting client to the server and then sending messages to it)
        client.h

        class QTcpSocket;
        
        class Client : public QObject
        {
            Q_OBJECT
        
        public:
            explicit Client(QObject *parent = nullptr);
        
        public slots:
            void sendMessage(QString, QString);
        
        private:
            QTcpSocket* tcpSocket { nullptr };
            QDataStream in;
        };
        

        client.cpp

        #include "client.h"
        #include <QtNetwork>
        
        Client::Client(QObject *parent)
            : QObject{parent}
            , tcpSocket(new QTcpSocket(this))
        {
            in.setDevice(tcpSocket);
            in.setVersion(QDataStream::Qt_4_0);
        }
        
        void Client::sendMessage(QString ip, QString port)
        {
            tcpSocket->abort();
            tcpSocket->connectToHost(ip, port.toInt());
        }
        

        main.qml

        Window {
            width: 300
            height: 200
            visible: true
            title: qsTr("Client")
            color: "lightblue"
        
            ColumnLayout {
                anchors.fill: parent
        
                TextField {
                    id: ipAddrs
                }
                TextField {
                        id: portNum
                    }
        
                RowLayout {
                    Layout.alignment: Qt.AlignBottom
        
                    TextField {
                        id: txtField
                        Layout.fillWidth: true
                    }
                    Button {
                        text: qsTr("Send")
                        onClicked:
                        myObject.sendMessage(ipAddrs.text.toString(), portNum.text.toString())
                    }
                }
            }
        
            MyObject{
                id: myObject
            }
        }
        

        server.h

        class QTcpServer;
        class QTcpSocket;
        
        class Server : public QObject
        {
            Q_OBJECT
        public:
            explicit Server(QObject *parent = nullptr);
        
        public slots:
            QString initServer();
            QString setMessage();
            void onNewConnection();
        
        private:
            QTcpServer* tcpServer { nullptr };
            QTcpSocket* tcpSocket { nullptr };
            QDataStream in;
        };
        

        server.cpp

        #include "server.h"
        #include <QtNetwork>
        #include <QtCore>
        
        Server::Server(QObject *parent)
            : QObject{parent}
            , tcpServer(new QTcpServer(this))
            , tcpSocket(new QTcpSocket(this))
        {
            initServer();
            in.setDevice(tcpSocket);
            in.setVersion(QDataStream::Qt_4_0);
            connect(tcpServer, &QTcpServer::newConnection, this, &Server::onNewConnection);
        }
        
        QString Server::initServer() {
        
            tcpServer = new QTcpServer(this);
            if(!tcpServer->listen())
                return "Server Unable to start the server: " +
                        tcpServer->errorString();
        
            QString ipAddress;
            QList<QHostAddress> ipAddressesList = QNetworkInterface::allAddresses();
        
            // use the first non-local IPv4 address
            for(int i=0; i<ipAddressesList.size(); ++i)
                if(ipAddressesList.at(i) != QHostAddress::LocalHost &&
                        ipAddressesList.at(i).toIPv4Address()) {
                    ipAddress = ipAddressesList.at(i).toString();
                    break;
                }
        
            // if we did not find one, use IPv4 localhost
            if(ipAddress.isEmpty())
                ipAddress = QHostAddress(QHostAddress::LocalHost).toString();
        
            return " The server is running on\n\n IP: " +
                    ipAddress + "\n port: " + QString::number(tcpServer->serverPort())
                    + "\n\n Run the Client example now.";
        }
        
        void Server::onNewConnection()
        {
            QTcpSocket *clientConnection = tcpServer->nextPendingConnection();
            connect(clientConnection, &QAbstractSocket::disconnected,
                    clientConnection, &QObject::deleteLater);
            connect(clientConnection, &QAbstractSocket::readyRead, this, &Server::setMessage);
        }
        
        QString Server::setMessage()
        {
            in.startTransaction();
        
            QString message;
            in >> message;
        
            if (!in.commitTransaction())
               return "commitTransaction error" ;
        
            return message;
        }
        

        main.qml

        Window {
            width: 300
            height: 200
            visible: true
            title: qsTr("Server")
            color: "lightblue"
        
            ColumnLayout {
                anchors.fill: parent
        
                Label {
                    text: myObject.initServer()
                }
        
                Label {
                    id: msgLabel
                    text: myObject.setMessage()
                }
            }
        
            MyObject{
                id: myObject
            }
        }
        

        For now I have only a question. Are the projects to this point fine? I mean I know that there may be many things to be added to them but isn't anything redundant up to here?

        Q Offline
        Q Offline
        qcoderpro
        wrote on last edited by
        #14

        When I run both projects, I get this issue for the client project:
        QIODevice::read (QTcpSocket): device not open and the error message: commitTransaction error
        on the server's project's user interface. Let's for now ignore these.

        I type the IP and port numbers provided by the server UI into the text fields of the client project's UI and write "Hi" in the bottom text field and click on the button Send there for which the sendMessage slot is called and it connectes to the server successfully.

        void Client::sendMessage(QString ip, QString port)
        {
            tcpSocket->abort();
            tcpSocket->connectToHost(ip, port.toInt());
        }
        

        Afterwards, we've this connection in the Server project's constructor:
        connect(tcpServer, &QTcpServer::newConnection, this, &Server::onNewConnection);
        As well as:

        in.setDevice(tcpSocket);
        in.setVersion(QDataStream::Qt_4_0);
        

        The connection above calls onNewConnection slot since there's a new connection signal.

        void Server::onNewConnection()
        {
            QTcpSocket *clientConnection = tcpServer->nextPendingConnection();
            connect(clientConnection, &QAbstractSocket::disconnected,
                    clientConnection, &QObject::deleteLater);
            connect(clientConnection, &QAbstractSocket::readyRead, this, &Server::setMessage);
        }
        

        In that function the setMessage slot is called:

        QString Server::setMessage()
        {
            in.startTransaction();
        
            QString message;
            in >> message;
        
            if (!in.commitTransaction())
               return "commitTransaction error" ;
        
            return message;
        }
        

        in is already set to the socket in the constructor, so it's expected that it's able to get the message sent ('Hi') and return that message to the server's label front-end part where that slot is called (too)!
        But in reality no message is shown on the server's UI!

        Could you please tell me where the first mistake is in the code so that I can firstly fix it and then we go for the others?

        1 Reply Last reply
        0
        • SGaistS Offline
          SGaistS Offline
          SGaist
          Lifetime Qt Champion
          wrote on last edited by
          #15

          First thing: you initialize your QDataStream on the wrong socket, it shall use the socket matching the connection that was established.

          Interested in AI ? www.idiap.ch
          Please read the Qt Code of Conduct - https://forum.qt.io/topic/113070/qt-code-of-conduct

          Q 1 Reply Last reply
          1
          • SGaistS SGaist

            First thing: you initialize your QDataStream on the wrong socket, it shall use the socket matching the connection that was established.

            Q Offline
            Q Offline
            qcoderpro
            wrote on last edited by qcoderpro
            #16

            @SGaist

            Do you mean to move

            in.setDevice(tcpSocket);
            in.setVersion(QDataStream::Qt_4_0);
            

            from the server's constructor into the onNewConnection slot this way, please?

            void Server::onNewConnection()
            {
                QTcpSocket *clientConnection = tcpServer->nextPendingConnection();
                connect(clientConnection, &QAbstractSocket::disconnected,
                        clientConnection, &QObject::deleteLater);
                in.setDevice(clientConnection);
                in.setVersion(QDataStream::Qt_4_0);
                connect(clientConnection, &QAbstractSocket::readyRead, this, &Server::setMessage);
            }
            

            The error message when running the projects both at the same time: QDataStream: No transaction in progress

            Q 1 Reply Last reply
            0
            • Q qcoderpro

              @SGaist

              Do you mean to move

              in.setDevice(tcpSocket);
              in.setVersion(QDataStream::Qt_4_0);
              

              from the server's constructor into the onNewConnection slot this way, please?

              void Server::onNewConnection()
              {
                  QTcpSocket *clientConnection = tcpServer->nextPendingConnection();
                  connect(clientConnection, &QAbstractSocket::disconnected,
                          clientConnection, &QObject::deleteLater);
                  in.setDevice(clientConnection);
                  in.setVersion(QDataStream::Qt_4_0);
                  connect(clientConnection, &QAbstractSocket::readyRead, this, &Server::setMessage);
              }
              

              The error message when running the projects both at the same time: QDataStream: No transaction in progress

              Q Offline
              Q Offline
              qcoderpro
              wrote on last edited by
              #17

              No further help? :|

              1 Reply Last reply
              0
              • SGaistS Offline
                SGaistS Offline
                SGaist
                Lifetime Qt Champion
                wrote on last edited by
                #18

                Do you also use QDataStream to prepare the data to send ?

                Interested in AI ? www.idiap.ch
                Please read the Qt Code of Conduct - https://forum.qt.io/topic/113070/qt-code-of-conduct

                Q 2 Replies Last reply
                0
                • SGaistS SGaist

                  Do you also use QDataStream to prepare the data to send ?

                  Q Offline
                  Q Offline
                  qcoderpro
                  wrote on last edited by qcoderpro
                  #19
                  This post is deleted!
                  1 Reply Last reply
                  0
                  • SGaistS SGaist

                    Do you also use QDataStream to prepare the data to send ?

                    Q Offline
                    Q Offline
                    qcoderpro
                    wrote on last edited by
                    #20

                    @SGaist

                    Yes, you're right. I partly changed all six files to match the requirements as follows:
                    The server part:
                    server.h:

                    class Server : public QObject
                    {
                        Q_OBJECT
                    public:
                        explicit Server(QObject *parent = nullptr);
                    
                    public slots:
                        QString initServer();
                        void setMessage();
                        QString getMessage() const;
                        void onNewConnection();
                    
                    private:
                        QTcpServer* tcpServer { nullptr };
                        QDataStream in;
                        QString message;
                    };
                    

                    server.cpp:

                    Server::Server(QObject *parent)
                        : QObject{parent}
                        , tcpServer(new QTcpServer(this))
                    {
                        initServer();
                        connect(tcpServer, &QTcpServer::newConnection, this, &Server::onNewConnection);
                    }
                    
                    QString Server::initServer() {
                    //.. Provide the IP address and port number for the client
                    }
                    
                    void Server::onNewConnection()
                    {
                        QTcpSocket *clientConnection = tcpServer->nextPendingConnection();
                        connect(clientConnection, &QAbstractSocket::disconnected,
                                clientConnection, &QObject::deleteLater);
                        in.setDevice(clientConnection);
                        in.setVersion(QDataStream::Qt_4_0);
                        connect(clientConnection, &QAbstractSocket::readyRead, this, &Server::setMessage);
                    }
                    
                    void Server::setMessage()
                    {
                        in.startTransaction();
                        QString msg;
                        in >> msg;
                    
                        if (!in.commitTransaction())
                            message = "commitTransaction error" ;
                        else
                            message = msg;
                    }
                    
                    QString Server::getMessage() const
                    {
                        return message;
                    }
                    

                    server's qml file:

                     ColumnLayout {
                            anchors.fill: parent
                    
                            Label {
                                text: myObj.initServer()
                            }
                    
                            Label {
                                id: msgLabel
                                text: myObj.getMessage()
                            }
                        }
                    
                        ServerClass{
                            id: myObj
                        }
                    

                    The client part:

                    client.h:

                    class Client : public QObject
                    {
                        Q_OBJECT
                    
                    public:
                        explicit Client(QObject *parent = nullptr);
                    
                    public slots:
                        void sendAddress(QString, QString);
                        void sendMessage(const QString&);
                    
                    private:
                        QTcpSocket* tcpSocket { nullptr };
                        QDataStream out;
                    };
                    

                    client.cpp:

                    Client::Client(QObject *parent)
                        : QObject{parent}
                        , tcpSocket(new QTcpSocket(this))
                    {
                        out.setDevice(tcpSocket);
                        out.setVersion(QDataStream::Qt_4_0);
                    }
                    
                    void Client::sendAddress(QString ip, QString port)
                    {
                        tcpSocket->abort();
                        tcpSocket->connectToHost(ip, port.toInt());
                    }
                    
                    void Client::sendMessage(const QString& message)
                    {
                        out.startTransaction();
                        out << message;
                    
                        if (!out.commitTransaction())
                            return ;
                    }
                    

                    client's qml file:

                     ColumnLayout {
                            anchors.fill: parent
                    
                            TextField {
                                id: ipAddrs
                            }
                            TextField {
                                    id: portNum
                                }
                            Button {
                                text: "Send Address"
                                onClicked: myObj.sendAddress(ipAddrs.text.toString(), portNum.text.toString())
                            }
                    
                            RowLayout {
                                Layout.alignment: Qt.AlignBottom
                    
                                TextField {
                                    id: txtField
                                    Layout.fillWidth: true
                                }
                                Button {
                                    text: qsTr("Send")
                                    onClicked: myObj.sendMessage(txtField.text)
                                }
                            }
                        }
                    
                        ClientClass{
                            id: myObj
                        }
                    }
                    

                    After running both projects this way, and typing the IP address and port number (given by the server UI) on the client UI and writing a text message there I click on the Send button, but nothing is shown on the server UI.

                    I'm almost sure now the goal is closer but there're still a number of mistakes that need to be worked out.

                    1 Reply Last reply
                    0
                    • SGaistS Offline
                      SGaistS Offline
                      SGaist
                      Lifetime Qt Champion
                      wrote on last edited by
                      #21

                      Are you using the Fortune client and server examples as a base ?
                      If so, please take a look at the server side implementation, QDataStream is used there to write the data in a QByteArray that is then written in the socket. The transaction handling happens on the receiving end.

                      Interested in AI ? www.idiap.ch
                      Please read the Qt Code of Conduct - https://forum.qt.io/topic/113070/qt-code-of-conduct

                      Q 1 Reply Last reply
                      1
                      • SGaistS SGaist

                        Are you using the Fortune client and server examples as a base ?
                        If so, please take a look at the server side implementation, QDataStream is used there to write the data in a QByteArray that is then written in the socket. The transaction handling happens on the receiving end.

                        Q Offline
                        Q Offline
                        qcoderpro
                        wrote on last edited by
                        #22

                        @SGaist

                        Are you using the Fortune client and server examples as a base ?

                        Partly.

                        QDataStream is used there to write the data in a QByteArray that is then written in the socket.

                        I didn't know QString wouldn't work, but anyway, it's now changed to:

                        void Client::sendMessage(const QString& message)
                        {
                            QByteArray block;
                            QDataStream out(&block, QIODevice::WriteOnly);
                            out.setVersion(QDataStream::Qt_5_10);
                            out << message;
                        }
                        

                        But still no change in the result! :|

                        The transaction handling happens on the receiving end.

                        Yes, it's implemented in the setMessage() slot.

                        jsulmJ 1 Reply Last reply
                        0
                        • Q qcoderpro

                          @SGaist

                          Are you using the Fortune client and server examples as a base ?

                          Partly.

                          QDataStream is used there to write the data in a QByteArray that is then written in the socket.

                          I didn't know QString wouldn't work, but anyway, it's now changed to:

                          void Client::sendMessage(const QString& message)
                          {
                              QByteArray block;
                              QDataStream out(&block, QIODevice::WriteOnly);
                              out.setVersion(QDataStream::Qt_5_10);
                              out << message;
                          }
                          

                          But still no change in the result! :|

                          The transaction handling happens on the receiving end.

                          Yes, it's implemented in the setMessage() slot.

                          jsulmJ Offline
                          jsulmJ Offline
                          jsulm
                          Lifetime Qt Champion
                          wrote on last edited by
                          #23

                          @qcoderpro said in Sending messages from a client to server using network on the same machine:

                          But still no change in the result!

                          Because sendMessage does not send anything.
                          It only writes the message into a QByteArray.
                          You also need to send that QByteArray through the socket.

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

                          Q 1 Reply Last reply
                          1
                          • jsulmJ jsulm

                            @qcoderpro said in Sending messages from a client to server using network on the same machine:

                            But still no change in the result!

                            Because sendMessage does not send anything.
                            It only writes the message into a QByteArray.
                            You also need to send that QByteArray through the socket.

                            Q Offline
                            Q Offline
                            qcoderpro
                            wrote on last edited by
                            #24

                            @jsulm
                            Yeah, right, so I added this line at the end of the slot:
                            tcpSocket->write(block);
                            But I think there's an earlier problem. No connection arrives. I set a debug in the onNewConnection() slot in the server app but nothing is printed although I put the IP and port in the client and click on the "Send Address" button! :|

                            jsulmJ 1 Reply Last reply
                            0
                            • Q qcoderpro

                              @jsulm
                              Yeah, right, so I added this line at the end of the slot:
                              tcpSocket->write(block);
                              But I think there's an earlier problem. No connection arrives. I set a debug in the onNewConnection() slot in the server app but nothing is printed although I put the IP and port in the client and click on the "Send Address" button! :|

                              jsulmJ Offline
                              jsulmJ Offline
                              jsulm
                              Lifetime Qt Champion
                              wrote on last edited by
                              #25

                              @qcoderpro Then you should debug on the client side

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

                              Q 1 Reply Last reply
                              0
                              • jsulmJ jsulm

                                @qcoderpro Then you should debug on the client side

                                Q Offline
                                Q Offline
                                qcoderpro
                                wrote on last edited by qcoderpro
                                #26

                                @jsulm

                                The client's sendAddress slot sends the IP and port number as a string and int respectively, based on this version. So that connection is expected to be received in the server's NewConnection() slot, but it doesn't, I don't know why! :|

                                jsulmJ 1 Reply Last reply
                                0
                                • Q qcoderpro

                                  @jsulm

                                  The client's sendAddress slot sends the IP and port number as a string and int respectively, based on this version. So that connection is expected to be received in the server's NewConnection() slot, but it doesn't, I don't know why! :|

                                  jsulmJ Offline
                                  jsulmJ Offline
                                  jsulm
                                  Lifetime Qt Champion
                                  wrote on last edited by
                                  #27

                                  @qcoderpro said in Sending messages from a client to server using network on the same machine:

                                  sendAddress slot sends the IP and port number

                                  It does not send anything, it just calls connectToHost. Did you check what happens on client side? Is https://doc.qt.io/qt-5/qabstractsocket.html#connected emitted? Is https://doc.qt.io/qt-5/qabstractsocket.html#errorOccurred signal emitted?

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

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                                  • jsulmJ jsulm

                                    @qcoderpro said in Sending messages from a client to server using network on the same machine:

                                    sendAddress slot sends the IP and port number

                                    It does not send anything, it just calls connectToHost. Did you check what happens on client side? Is https://doc.qt.io/qt-5/qabstractsocket.html#connected emitted? Is https://doc.qt.io/qt-5/qabstractsocket.html#errorOccurred signal emitted?

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                                    qcoderpro
                                    wrote on last edited by
                                    #28

                                    @jsulm

                                    I set this in the client's sendAddress slot:

                                    connect(tcpSocket, &QAbstractSocket::connected, []() {
                                           qDebug() << "Connected to the host";
                                       });
                                    

                                    And it prints that message on Application Output window. So the connection is assumed to be established correctly without errors. Right?

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                                    • Q qcoderpro

                                      @jsulm

                                      I set this in the client's sendAddress slot:

                                      connect(tcpSocket, &QAbstractSocket::connected, []() {
                                             qDebug() << "Connected to the host";
                                         });
                                      

                                      And it prints that message on Application Output window. So the connection is assumed to be established correctly without errors. Right?

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                                      qcoderpro
                                      wrote on last edited by
                                      #29

                                      No further contribution? :(

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                                      • Q qcoderpro

                                        No further contribution? :(

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                                        Bob64
                                        wrote on last edited by
                                        #30

                                        @qcoderpro I'd suggest that you go back to the fortune example and debug what is happening on the client and server side until you have a good understanding. I found it very useful when I was figuring out how Qt did sockets.

                                        Do you have any background with sockets at all? If not, I wonder if it would be worth having a play around with something like Python first to firm up the ideas. The official Python docs on sockets are very good.

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                                        • B Bob64

                                          @qcoderpro I'd suggest that you go back to the fortune example and debug what is happening on the client and server side until you have a good understanding. I found it very useful when I was figuring out how Qt did sockets.

                                          Do you have any background with sockets at all? If not, I wonder if it would be worth having a play around with something like Python first to firm up the ideas. The official Python docs on sockets are very good.

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                                          qcoderpro
                                          wrote on last edited by
                                          #31

                                          @Bob64
                                          The fortune client/server apps are different from (at least) that point of view that the server sends messages to the client by a button on the client. It's way different from mine.
                                          Well, these two QML apps are considerably simple but I don't know why we (helpers and me) can't work it out and get them to work! :(

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