Question

I have a server application which sends some xor encrypted strings. I am reading them from my QT client application. Sometimes, the server is slower and I am not able to receive the entire string. I have tried something like below but it gets stuck ( see the comment below). How can I wait until I have the entire data. I tried bytesAviable() but then again i get stuck (infinite loop)

QTcpSocket * sock = static_cast<QTcpSocket*>(this->sender());
if (key == 0)
{
    QString recv(sock->readLine());
    key = recv.toInt();
    qDebug() << "Cheia este " << key;

    char * response = enc_dec("#AUTH|admin|admin",strlen("#AUTH|admin|admin"),key);
    sock->write(response);
}
else
{
    busy = true;
    while (sock->bytesAvailable() > 0)
    {
        unsigned short word;
        sock->read((char*)(&word),2);
        qDebug()<<word;
        //Sleep(100); if i do this than it works great!
        QByteArray bts = sock->read(word);
        while (bts.length() < word)
        {
            char bit; //here get's stuck
            if (sock->read(&bit,1) > 0)
                bts.append(bit);
            sock->flush();
        }

        char * decodat = enc_dec((char*)bts.data(),bts.length() - 2,key);
        qDebug() << decodat;
    }

}

Answer 1

I offer you to do the following:

QObject::connect(this->m_TCPSocket, SIGNAL(readyRead()), this, SLOT(processRecivedDatagrams()));

Some explanation:

1. It is convinient to create a class instance of which will manage network;
2. One has the member which is pointer on TCPSocket;
3. In constructor implement connection of signal from socket readyRead() which is emmited when needed data was delivered with SLOT(processRecivedDatagrams()). which is responsible for processing recived datagrams/ in this case it is processRecivedDatagrams(), also implement this slot

Mind that class which manages network has to inherit from QObject and also in its declaration include macrosQ_OBject` for MOC.

update:

i also offer you to store recived data in container like stack or queue this will allow you to synhronize sender and reciver (container in this case acts like buffer)

// SLOT:


void Network::processRecivedDatagrams(void)
{
    if (!this->m_flagLocked) // use analog of mutex 
    {
        this->m_flagLocked = true; // lock resource

    QByteArray datagram;
    do 
    {
        datagram.resize(m_TCPSocket->pendingDatagramSize());
        m_TCPSocket->readDatagram(datagram.data(), datagram.size());
    }
            Qt::String YourString; // actualy I don`t remember how to declare Qt string
    while (m_TCPSocket->hasPendingDatagrams());
    QDataStream in (&datagram, QIODevice::ReadOnly);

        in  >> YourString



        --numberOfDatagrams;
    }

    this->m_flagLocked = false; // unlock resource
}

}