[Solved] TcpSocket timeout HELP

nitramuk

Hi
Hope this is the correct place to post ?

Can anyone please give me any pointers as to why i keep getting time out errors from a tcpsocket ?

According to a packet sniffer the data is being sent well within the timeslot but my code times out about 90% of the time !

Function is pasted below
The command gets sent ok
The data gets sent ok
The reply packet length gets received ok
The reply packet times out 90% of the time !
Even though according to network sniffing the data HAS BEEN sent from the server ??

This has been bugging me for days.
Any help much appreciated.

@// Send a complex command with data attached
void CtcpClient::slotCommand(const QString commandStr,const QString dataStr )
{
// Output stream
QTextStream outText(socket);

// Send command
if (commandStr.length ()<4)
{
emit sigError (TCPERR_INVALID_COMMAND,"Invalid command");
return;
}
outText << commandStr.left (4);
outText.flush ();

// Send data length
if (dataStr.length ()<1)
{
emit sigError (TCPERR_INVALID_DATA,"Invalid data");
return;
}
QString dataLen = QString::number (dataStr.size ()).rightJustified (4,'0');
outText << dataLen;
outText.flush ();

// Send data
outText << dataStr;
outText.flush ();

// Wait untill we have 4 bytes of data ( packet length )
while (socket->bytesAvailable ()< 4)
{
if (!socket->waitForReadyRead(Timeout))
{
emit sigError(socket->error(), socket->errorString());
return;
}
}

// Then read packet length
QTextStream inLength(socket);
QString packetLen = inLength.read (4);

// Wait untill we have packetlength of data

while (socket->bytesAvailable ()< packetLen.toInt ())
{
if (!socket->waitForReadyRead(Timeout))
{
emit sigError(socket->error(), socket->errorString()); // +++++++ KEEPS EXITING HERE +++++++++
return;
}
}

// Then read data
QTextStream inData(socket);
QString data = inData.read (packetLen.toInt ());

// Then emit sigReply(packet)
emit sigReply (data);
}@

dangelog

You need to return to the event loop or call waitForBytesWritten on the socket.

andre

Yes. If possible at all, I would recommend you use the first approach peppe suggests: return to the eventloop.

That means, that you split up your code in sections, and use QTcpSocket's signals and slots to trigger actions. Avoid the waitFor* functions if at all possible.

nitramuk

Hi.
Many thanks peppe & Andre.
Between the two of you my problem is solved !

Had to do a fairly major rewrite of both server and client so replies could be associated with the relevant sent command, and as suggested moved receiving on the client to a separate slot connected to TcpSocket.ReadyRead() signal.

This solved all time-out issues.

Again many thanks for the help it was much appreciated ( and needed ).

andre

Thank you for reporting back with your solution!