Hi,

I am quite new using QT and I am trying to implement a TPC-IP server- client. The server has to read every 0.1sec a line of a file with latitude and longitude and send it to the client. But right now I can connect server and client but the client receive nothing. Could someone help me?? Thanks in advance.

SERVER
main.cpp
Qt Code: 
  1. #include <iostream>
  2. #include <QCoreApplication>
  3. #include "server.h"
  4.  
  5. int main(int argc, char *argv[]){
  6.     QCoreApplication app(argc, argv);
  7.     QString ipaddress = QString(argv[1]);
  8.     int port = atoi(argv[2]);
  9.     Server* server = new Server("127.0.0.1", 1234);
  10.     int retVal = app.exec();
  11.     return retVal;
  12. }
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server.cpp

Qt Code: 
  1. include "server.h"
  2. #include <iostream>
  3. #include <QTcpServer>
  4. #include <QTcpSocket>
  5. #include <QTimer>
  6. #include <QDateTime>
  7. #include <QSettings>
  8. #include "readdata.h"
  9.  
  10. Server::Server(QString ipAddress, int port, QObject *parent) :
  11.     QObject(parent), mTcpServer(0), mTcpSocket(0)
  12. {
  13.     mTcpServer = new QTcpServer(this);
  14.     connect(mTcpServer, SIGNAL(newConnection()), this, SLOT(newConnectionSlot()));
  15.     if (!mTcpServer->listen(QHostAddress(ipAddress), port)) {
  16.         std::cout << "Unable to start the server: " << mTcpServer->errorString().toStdString() << std::endl;
  17.         return;
  18.     }
  19.  
  20.     std::cout << "The server is running on\n\nIP: "<< ipAddress.toStdString()
  21.             << "\nport: " << mTcpServer->serverPort() << "\n\nRun the Client now.\n" << std::endl;
  22. }
  23.  
  24. void Server::newConnectionSlot()
  25. {
  26.     mTcpSocket = mTcpServer->nextPendingConnection();
  27.     connect(mTcpSocket, SIGNAL(disconnected()),
  28.             mTcpSocket, SLOT(deleteLater()));
  29.  
  30.     // setup timer to send data at a given interval
  31.     mSendTimer = new QTimer(this);
  32.     connect(mSendTimer, SIGNAL(timeout()),
  33.             this, SLOT(sendSlot()));
  34.     mSendTimer->start(40);
  35. }
  36.  
  37. void Server::sendSlot()
  38. {
  39.     if(!mTcpSocket)
  40.         return;
  41.  
  42.     readPathData("/home/jorge/Desktop/INStest.kml", &latitude, &longitude);
  43.  
  44.     QByteArray block;
  45.     QDataStream out(&block, QIODevice::WriteOnly);
  46.     out.setVersion(QDataStream::Qt_4_0);
  47.     out << (quint16)0;
  48.  
  49.     for(int i=0; i < latitude.size(); i++){
  50.         positionTest.append(QString::number(latitude[i]) + " " + QString::number(longitude[i]) + /*" " + QString::number(height[i])+*/ "\n");
  51.         data << positionTest[i];
  52.         out << data.at(qrand() % data.size());
  53.         out.device()->seek(0);
  54.         out << (quint16)(block.size() - sizeof(quint16));
  55.         qint64 written_lat = mTcpSocket->write(block, block.size());
  56.     }
  57. }
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server.h
Qt Code: 
  1. #ifndef SERVER_H_
  2. #define SERVER_H_
  3.  
  4. #include <QObject>
  5. #include <QVector>
  6. #include <QStringList>
  7.  
  8. QT_BEGIN_NAMESPACE
  9. class QTcpServer;
  10. class QNetworkSession;
  11. class QTcpSocket;
  12. class QTimer;
  13. QT_END_NAMESPACE
  14.  
  15. class Server : public QObject
  16. {
  17.     Q_OBJECT
  18.  
  19. public:
  20.     Server(QString ipAddress, int port, QObject *parent = 0);
  21.  
  22. private slots:
  23.     void newConnectionSlot();
  24.     void sendSlot();
  25.  
  26. private:
  27.     QTcpServer          *mTcpServer;
  28.     QTcpSocket          *mTcpSocket;
  29.     QTimer              *mSendTimer;
  30.  
  31.  
  32.     QVector<double> latitude;
  33.     QVector<double> longitude;
  34.     QVector<double> height;
  35.     QString latitudeTest;
  36.     QString longitudeTest;
  37.     QString heightTest;
  38.     QVector<QString> positionTest;
  40.  
  41. };
  42.  
  43. #endif /* SERVER_H_ */
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readData.cpp
Qt Code: 
  1. #include <QFile>
  2. #include <QTextStream>
  3. #include "readdata.h"
  4. #include "QPoint"
  5.  
  6. void readPathData(QString filename, QVector<double>* latitude, QVector<double>* longitude)
  7. {
  8.     QFile file;
  9.     file.setFileName(filename);
  10.     file.open(QIODevice::ReadOnly);
  11.     QByteArray line = file.readLine(); //Read two first lines of the .kml file
  12.     line = file.readLine();
  13.  
  14.     while (!file.atEnd()) {
  15.         QByteArray line = file.readLine();
  16.         if(line[0] != '<')
  17.         {
  18.             double lon;
  19.             double lat;
  20.             double hei;
  21.  
  22.             QList<QByteArray> values = line.split(',');
  23.  
  24.             hei = atof(values.at(2).constData());
  25.             lat = atof(values.at(1).constData());
  26.             lon = atof(values.at(0).constData());
  27.  
  28.             if (latitude)
  29.                 latitude->append(lat);
  30.  
  31.  
  32.             if (longitude)
  33.                 longitude->append(lon);
  34.         }
  35.     }
  36.     file.close();
  37. }
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readData.h
Qt Code: 
  1. #include <QString>
  2. #include <QVector>
  3.  
  4. #ifndef READDATA
  5. #define READDATA
  6.  
  7. void readPathData(QString filename, QVector<double>* latitude, QVector<double>* longitude/*, QVector<double>* height*/);
  8.  
  9. #endif // READDATA
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CLIENT
main.cpp
Qt Code: 
  1. #include <iostream>
  2. #include <QCoreApplication>
  3.  
  4. #include "client.h"
  5.  
  6. int main(int argc, char *argv[]){
  7.     QCoreApplication app(argc, argv);
  8.     QString ipaddress = QString(argv[1]);
  9.     int port = atoi(argv[2]);
  10.     Client* client = new Client("127.0.0.1", 1234);
  11.     int retVal = app.exec();
  12. }
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client.cpp
Qt Code: 
  1. #include "client.h"
  2. #include <iostream>
  3. #include <QTcpSocket>
  4. #include <QSettings>
  5. #include <QDateTime>
  6.  
  7. Client::Client(QString ipAddress, int port, QObject *parent):
  8.     QObject(parent), mTcpSocket(0), mIpAddress(ipAddress), mPort(port)
  9. {
  10.     mTcpSocket = new QTcpSocket(this);
  11.     connect(mTcpSocket, SIGNAL(readyRead()),
  12.             this, SLOT(readSlot()));
  13.     connect(mTcpSocket, SIGNAL(error(QAbstractSocket::SocketError)),
  14.             this, SLOT(displayErrorSlot(QAbstractSocket::SocketError)));
  15.  
  16.     std::cout << "Connecting to ip: " << mIpAddress.toStdString() << " port: " << mPort << std::endl;
  17.     mTcpSocket->connectToHost(mIpAddress, mPort);
  18. }
  19.  
  20. void Client::readSlot()
  21. {
  22.     static qint64 starttime = QDateTime::currentMSecsSinceEpoch();
  23.     static int frames = 0;
  24.  
  25.     qint64 blockSize = 1440000; //in bytes
  26.  
  27.     QDataStream in(mTcpSocket);
  28.  
  29.     if (blockSize == 0) {
  30.         if (mTcpSocket->bytesAvailable() < (int)sizeof(quint32))
  31.             return;
  32.         in >> blockSize;
  33.     }
  34.  
  35.     if (mTcpSocket->bytesAvailable() < 38)
  36.         return;
  37.  
  38.     QString nextPos;
  39.     in >> nextPos;
  40.     currentPos = nextPos;
  41.  
  42.     char* data = (char*) malloc(blockSize);
  43.     qint64 bytesRead = mTcpSocket->read(data, blockSize);
  44.     free(data);
  45.     qDebug() << "Data" << data;
  46.     qDebug() << "Position" << currentPos;
  47.  
  48. }
  49.  
  50. void Client::displayErrorSlot(QAbstractSocket::SocketError socketError)
  51. {
  52.     switch (socketError) {
  53.     case QAbstractSocket::RemoteHostClosedError:
  54.         break;
  55.     case QAbstractSocket::HostNotFoundError:
  56.         std::cout << "The host was not found. Please check the "
  57.                                     "host name and port settings."<< std::endl;
  58.         break;
  59.     case QAbstractSocket::ConnectionRefusedError:
  60.         std::cout << "The connection was refused by the peer. "
  61.                                     "Make sure the fortune server is running, "
  62.                                     "and check that the host name and port "
  63.                                     "settings are correct."<< std::endl;
  64.         break;
  65.     default:
  66.         std::cout << "The following error occurred: " << mTcpSocket->errorString().toStdString() << std::endl;
  67.         break;
  68.     }
  69. }
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client.h
Qt Code: 
  1. #ifndef CLIENT_H_
  2. #define CLIENT_H_
  3.  
  4. #include <QObject>
  5. #include <QAbstractSocket>
  6.  
  7. QT_BEGIN_NAMESPACE
  8. class QTcpSocket;
  9. QT_END_NAMESPACE
  10.  
  11. class Client : public QObject
  12. {
  13.     Q_OBJECT
  14. public:
  15.     Client(QString ipAddress, int port, QObject *parent=0);
  16.  
  17. private slots:
  18.     void readSlot();
  19.     void displayErrorSlot(QAbstractSocket::SocketError);
  20.  
  21. private:
  22.     QTcpSocket          *mTcpSocket;
  23.     QString             mIpAddress;
  24.     int                 mPort;
  25.     QString currentPos;
  26. };
  27.  
  28. #endif /* CLIENT_H_ */
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