QSslSocket to much data?

[Qiieha]

Hi
I developed a Client Server Application with QSslSocket. It works very fine, but if I transfer a big amount of QDataStream
the client receives nothing. The readyReadSlot of the Client gets executed about 23 times, but in the end there is no data.

Does somebody know, what's wrong??

thank u

[wysota]

You are probably using QDataStream incorrectly.

[Qiieha]

Thank u...
No i use it correctly...like fortune example....

[wysota]

You mean the broken fortune example that doesn't expect to receive much data?

Ok then, I'll be here in case you eliminate all other possibilities and come to a conclusion you are not using QDataStream correctly.

[Qiieha]

ok, i use it this way:

server send-method

void Server::send_xml_data(QString message) {
    blockSize = 0;
    QString out_string = message;
    QByteArray block;
    QDataStream out_stream(&block, QIODevice::WriteOnly);
    out_stream.setVersion(QDataStream::Qt_4_7);
    out_stream << (qint16)0;
    out_stream << out_string;
    out_stream.device()->seek(0);
    out_stream << quint16(block.size() - sizeof(quint16));
    socket->write(block);
}

void Server::send_xml_data(QString message) {
    blockSize = 0;
    QString out_string = message;
    QByteArray block;
    QDataStream out_stream(&block, QIODevice::WriteOnly);
    out_stream.setVersion(QDataStream::Qt_4_7);
    out_stream << (qint16)0;
    out_stream << out_string;
    out_stream.device()->seek(0);
    out_stream << quint16(block.size() - sizeof(quint16));
    socket->write(block);
}

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client-readyReadSlot-method:

void Client::readyReadSlot()
{
    qDebug() << "readyReadSlot()";
    QDataStream in(socket);
    in.setVersion(QDataStream::Qt_4_7);
    if (blockSize == 0) {
        if (socket->bytesAvailable() < (int)sizeof(quint16))
            return;
        in >> blockSize;
    }
    if (socket->bytesAvailable() < blockSize)
             return;
 
    QString result;
    in >> result;
    receive(result); //process my data
}

void Client::readyReadSlot()
{
    qDebug() << "readyReadSlot()";
    QDataStream in(socket);
    in.setVersion(QDataStream::Qt_4_7);
    if (blockSize == 0) {
        if (socket->bytesAvailable() < (int)sizeof(quint16))
            return;
        in >> blockSize;
    }
    if (socket->bytesAvailable() < blockSize)
             return;

    QString result;
    in >> result;
    receive(result); //process my data
}

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[wysota]

What if blockSize > size of the socket's read buffer?

[ChrisW67]

... or the serialised form of the string is longer than 65536 bytes at the sending end?

[Qiieha]

Ok , you persuaded me...but how can I work around?

How can I enlarge the socket's read buffer?

[ChrisW67]

How many bytes is a "big amount of QDataStream"?

[Qiieha]

For example 133612 bytes...

[ChrisW67]

Firstly, your 16-bit byte count for the transmitted packet is inadequate.

In short, don't rely on the operating system or Qt to buffer data for you, and don't assume it will turn up all at once. Since the data packet can easily fit into memory this is the usual flow of things:

• You have a QByteArray buffer to hold unprocessed received data (as a member of the Client class)
• In response to readyRead():
  
  • Add all available bytes to that buffer.
  • While the buffer contains a complete packet, process that packet and remove it from the front of the buffer.
  • Leave any unprocessed part-packet in the buffer and leave the readyRead() handler.