QTcpSocket can't read already written data from QTcpServer

francescmm

I'm doing a threaded server that creates a thread for each incomming connection from a client. In the other side I have a client that only writes and receives data without threads. The problem is that when I discover a new client (using Server::incomingConnection(int) ) I start a thread with the socketDescriptor as parameter. This thread creates a socket to communicate with the client in the ServerThread::start() method and there written data is sent to the client as "Werlcome!" message.

Data is sent and in the client a readyRead() signal is emit. I catch it and try to show incomming data. The problem is that when I call socket->canReadLine() in the client, it returns false.

Brief description of structure: A Server (inherits QTcpServer) has a list of ServerThread. Each ServerThread (inherits QThread) is created and started in the Server::incommingConnection(int). Each ServerThread contains one Client (inherits QTcpSocket) where data is read or written.

I post the code although it is a lot:

SERVER

Server.cpp
@void Server::incomingConnection(int socketDescriptor)
{
ServerThread *thread = new ServerThread(socketDescriptor);
threadList.append(thread);
connect(thread, SIGNAL(receivedMsg(QString)), this, SLOT(msgFromThread(QString)));
connect(thread, SIGNAL(closeThread(int)), this, SLOT(threadFinished(int)));
connect(thread, SIGNAL(finished()), thread, SLOT(deleteLater()));
thread->start();
}

void Server::writeToClients(const QString &_msg)
{
for (int i = 0; i < threadList.size(); i++)
threadList.at(i)->writeMsg(_msg);
}
@

ServerThread.cpp
@ServerThread::ServerThread(int socketDescriptor, QObject *parent) : QThread(parent)
{
socketId = socketDescriptor;
client = new Client();
client->moveToThread(this);
}

void ServerThread::run()
{
connect(client, SIGNAL(readyRead()), this, SLOT(readyRead()));
connect(client, SIGNAL(disconnected()), this, SLOT(disconnectClient()));

client->setSocketDescriptor(socketId);

qDebug() << QString("[%1] New client from %2").arg(QDateTime::currentDateTime().toString("dd/MM/yyyy hh:mm:ss")).arg(client->peerAddress().toString());

client->write("Connected to server!");
client->waitForBytesWritten();

while (client->isOpen())
    client->waitForReadyRead(1000);

delete client;
client = NULL;

emit closeThread(socketId);

}

void ServerThread::readyRead()
{
QTcpSocket clSender = (QTcpSocket)sender();

qDebug() << QString("Received missage from client [%1]").arg(clSender->peerAddress().toString());

}

void ServerThread::writeMsg(const QString &msg)
{
qDebug()<<client->write(QString("Connected to server!").toLatin1());
client->waitForBytesWritten(15);
}
@

CLIENT
Client.cpp
@GadaTester::GadaTester(const QString &nif, QWidget *parent) : ui(new Ui::GadaTester)
{
setAttribute(Qt::WA_DeleteOnClose);

user = nif;
ui->setupUi(this);

socket = new QTcpSocket(this);

connect(socket, SIGNAL(connected()), this, SLOT(connected()));
connect(socket, SIGNAL(readyRead()), this, SLOT(readMsg()));
connect(socket, SIGNAL(disconnected()), this, SLOT(connectionClosedByServer()));

connect(ui->pbConnect, SIGNAL(clicked()), this, SLOT(restoreConnection()));
connect(ui->pbSend, SIGNAL(clicked()), this, SLOT(sendMsg()));
connect(ui->pbStop, SIGNAL(clicked()), this, SLOT(closeSocket()));
connect(ui->pbClose, SIGNAL(clicked()), this, SLOT(close()));

addAction(ui->actionClose);

}

void GadaTester::restoreConnection()
{
qDebug()<<"Connecting to server...";
socket->connectToHost(QHostAddress::LocalHost, PORT);
}

void GadaTester::connected()
{
socket->write(QString("Informacio del nom del socket").toLatin1());
socket->waitForBytesWritten();

ui->pbConnect->setEnabled(false);
ui->pbStop->setEnabled(true);

qDebug()<<QString("Connected to host %1:%2.\n").arg(socket->peerAddress().toString()).arg(socket->peerPort()));

}

void GadaTester::sendMsg()
{
socket->write("SOCKET_INFO;Missage 1");
socket->waitForBytesWritten();
}

void GadaTester::readMsg()
{
qDebug()<<"Received answer.";

QString line = "";

while (socket->canReadLine()) //Always returns false
    line += socket->readLine().trimmed();

qDebug()<<line;

}
@

SGaist

Hi,

It seems that you suffer from the same problem as in your other thread.

Add a "\n" to your string in sendMsg and you should be good.

You might also be interested by bytesAvailable

Hope it helps

dbzhang800

Maybe QAbstractSocket::flush() will be useful.