problem with QByteArray data !

[Con Nít]

i am writing a chat application using TCP.
i found a simple exemple of text chat here : http://www.qtcentre.org/wiki/index.p...le=Simple_chat.
i edited its code so that it can send QByteArray data instead of Qstring like it did in the beginning,but after editing, Server didn't send back message to clients.
help me fix my code.

a part of simplechatclient.cpp :

void SimpleChatClient::sendMessage()
{
    if(socket == NULL) return;
    if(socket->state() != QAbstractSocket::ConnectedState ) return;
    QString msg = "TEXT";
    QString data = "<" + nick->text().toLatin1() + "> " + message->text().toLatin1() + "\n";
    QByteArray block;
    QDataStream out(&block, QIODevice::WriteOnly);
    out.setVersion(QDataStream::Qt_4_2);
    out << (quint32) 0;
    out << msg;
    out << data;
    out.device()->seek(0);
    out << (quint32)(block.size() - sizeof(quint32));
 
    socket->write(block);
    socket->flush();
    message->clear();
    QMessageBox::information( new QWidget, "Application name",
        "Client send ok." );
}
 
void SimpleChatClient::receiveMessage()
{
    if (socket == NULL) return;
    if (socket->state() != QAbstractSocket::ConnectedState) return;
 
    QDataStream in(socket);
    in.setVersion(QDataStream::Qt_4_2);
            //in.setVersion( in.version() ); // set to the current Qt version instead
 
    if(blockSize == 0) {
        if (socket->bytesAvailable() < (int)sizeof(quint32)) return;
            in >> blockSize;
    }
 
    if(socket->bytesAvailable() < blockSize) return;
    QString msgString;
    QString msgData;
    in >> msgString;
    in >> msgData;
 
    chat->append(msgData);
 
    blockSize = 0;
 
    if(socket->bytesAvailable() > 0) receiveMessage();
}

void SimpleChatClient::sendMessage()
{
    if(socket == NULL) return;
    if(socket->state() != QAbstractSocket::ConnectedState ) return;
    QString msg = "TEXT";
    QString data = "<" + nick->text().toLatin1() + "> " + message->text().toLatin1() + "\n";
    QByteArray block;
    QDataStream out(&block, QIODevice::WriteOnly);
    out.setVersion(QDataStream::Qt_4_2);
    out << (quint32) 0;
    out << msg;
    out << data;
    out.device()->seek(0);
    out << (quint32)(block.size() - sizeof(quint32));

    socket->write(block);
    socket->flush();
    message->clear();
    QMessageBox::information( new QWidget, "Application name",
        "Client send ok." );
}

void SimpleChatClient::receiveMessage()
{
    if (socket == NULL) return;
    if (socket->state() != QAbstractSocket::ConnectedState) return;

    QDataStream in(socket);
    in.setVersion(QDataStream::Qt_4_2);
            //in.setVersion( in.version() ); // set to the current Qt version instead

    if(blockSize == 0) {
        if (socket->bytesAvailable() < (int)sizeof(quint32)) return;
            in >> blockSize;
    }

    if(socket->bytesAvailable() < blockSize) return;
    QString msgString;
    QString msgData;
    in >> msgString;
    in >> msgData;

    chat->append(msgData);

    blockSize = 0;

    if(socket->bytesAvailable() > 0) receiveMessage();
}

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a part of simplechatsever.cpp :

void SimpleChatServer::receiveMessage()
{
	QTcpSocket* socket = static_cast<QTcpSocket*>(sender());
 
        if (socket == NULL) return;
        if ( socket->state() != QAbstractSocket::ConnectedState ) return;
 
        QDataStream in(socket);
        in.setVersion(QDataStream::Qt_4_2);
 
        if (blockSize == 0) {
            if (socket->bytesAvailable() < (int)sizeof(quint32)) return;
            in >> blockSize;
        }
        if (socket->bytesAvailable() < blockSize) return;
        QString msgString;
        QString msgData;
        in >> msgString;
        in >> msgData;
 
        emit onMessage( msgString, msgData );
        blockSize = 0;
        if (socket->bytesAvailable() > 0) receiveMessage();
 
}
void SimpleChatServer::onMessage(const QString &msg, const QString &data)
{
    QByteArray block;
    QDataStream out(&block, QIODevice::WriteOnly);
    out.setVersion(QDataStream::Qt_4_2);
    out << (quint32) 0;
    out << msg;
    out << data;
    out.device()->seek(0);
    out << (quint32)(block.size() - sizeof(quint32));
    foreach (QTcpSocket* connection, connections)
    {
        connection->write(block);
        connection->flush();
    }
}

void SimpleChatServer::receiveMessage()
{
	QTcpSocket* socket = static_cast<QTcpSocket*>(sender());

        if (socket == NULL) return;
        if ( socket->state() != QAbstractSocket::ConnectedState ) return;

        QDataStream in(socket);
        in.setVersion(QDataStream::Qt_4_2);

        if (blockSize == 0) {
            if (socket->bytesAvailable() < (int)sizeof(quint32)) return;
            in >> blockSize;
        }
        if (socket->bytesAvailable() < blockSize) return;
        QString msgString;
        QString msgData;
        in >> msgString;
        in >> msgData;

        emit onMessage( msgString, msgData );
        blockSize = 0;
        if (socket->bytesAvailable() > 0) receiveMessage();

}
void SimpleChatServer::onMessage(const QString &msg, const QString &data)
{
    QByteArray block;
    QDataStream out(&block, QIODevice::WriteOnly);
    out.setVersion(QDataStream::Qt_4_2);
    out << (quint32) 0;
    out << msg;
    out << data;
    out.device()->seek(0);
    out << (quint32)(block.size() - sizeof(quint32));
    foreach (QTcpSocket* connection, connections)
    {
        connection->write(block);
        connection->flush();
    }
}

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[high_flyer]

i edited its code so that it can send QByteArray data instead of Qstring like it did in the beginning,but after editing, Server didn't send back message to clients.

I hope you don't expect us to go to the other thread, and compare the code there with your code.
Please post the changes you made so that we can see them in relation to the original.

[Con Nít]

i' sorry .

this is the original code :

a part of simplechatclient.cpp :

void SimpleChatClient::sendMessage()
{
	// "<nick> message\n"
	socket->write("<" + nick->text().toLatin1() + "> " + message->text().toLatin1() + "\n");
	message->clear();
}
 
void SimpleChatClient::receiveMessage()
{
	// missing some checks for returns values for the sake of simplicity
	qint64 bytes = buffer->write(socket->readAll());
	// go back as many bytes as we just wrote so that it can be read
	buffer->seek(buffer->pos() - bytes);
	// read only full lines, line by line
	while (buffer->canReadLine())
	{
		QString line = buffer->readLine();
		chat->append(line.simplified());
	}
}

void SimpleChatClient::sendMessage()
{
	// "<nick> message\n"
	socket->write("<" + nick->text().toLatin1() + "> " + message->text().toLatin1() + "\n");
	message->clear();
}

void SimpleChatClient::receiveMessage()
{
	// missing some checks for returns values for the sake of simplicity
	qint64 bytes = buffer->write(socket->readAll());
	// go back as many bytes as we just wrote so that it can be read
	buffer->seek(buffer->pos() - bytes);
	// read only full lines, line by line
	while (buffer->canReadLine())
	{
		QString line = buffer->readLine();
		chat->append(line.simplified());
	}
}

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a part of simplechatsever.cpp :

void SimpleChatServer::receiveMessage()
{
	QTcpSocket* socket = static_cast<QTcpSocket*>(sender());
	QBuffer* buffer = buffers.value(socket);
 
	// missing some checks for returns values for the sake of simplicity
	qint64 bytes = buffer->write(socket->readAll());
	// go back as many bytes as we just wrote so that it can be read
	buffer->seek(buffer->pos() - bytes);
	// read only full lines, line by line
	while (buffer->canReadLine())
	{
		QByteArray line = buffer->readLine();
		foreach (QTcpSocket* connection, connections)
		{
			connection->write(line);
		}
	}
}

void SimpleChatServer::receiveMessage()
{
	QTcpSocket* socket = static_cast<QTcpSocket*>(sender());
	QBuffer* buffer = buffers.value(socket);
	
	// missing some checks for returns values for the sake of simplicity
	qint64 bytes = buffer->write(socket->readAll());
	// go back as many bytes as we just wrote so that it can be read
	buffer->seek(buffer->pos() - bytes);
	// read only full lines, line by line
	while (buffer->canReadLine())
	{
		QByteArray line = buffer->readLine();
		foreach (QTcpSocket* connection, connections)
		{
			connection->write(line);
		}
	}
}

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I had fix only at these methods And declare quint32 blockSize in the header file.

[squidge]

Did you not try to debug your code before posting here?

Eg. does sendMessage transmit a valid message?
Which lines of receiveMessage are actually executed?

[Con Nít]

i try to debug program and i get some error on "if (socket->bytesAvailable() < blockSize) return; ", i delete it from my source code then sendMessage and receiveMessage run on both server and client, but messenge data not receive, i have just known a little about it, but not mastered yet!

help me ,i really need it :-(( thank in advance .

[Con Nít]

UP ... help me :-(( i verry need it :-S

[wysota]

Check what blockSize contains after you stream data to it from the data stream.

By the way, I think the code for the chat needs to be reviewed. Creating a data stream in a slot connected to readyRead() is really a bad idea.