Qt tcp/ip server (sort of) works with raw telnet, but not python, netcat or PuTTy w/telnet

  • I have a Qt tcp/ip server listening on a port. I can talk to it with telnet, but when I try with netcat the input commands are truncated. When I try to send it a command through python, it doesn't see anything. The strangest behaviour is with PuTTY (see below). Has anyone else run into an issue like this with a Qt tcp server? Code follows.


    @QTcpServer remoteControlServer;

    remoteControlClient = remoteControlServer.nextPendingConnection();

    connect(remoteControlClient, SIGNAL(readyRead()), this, SLOT(remoteCommandRead()));@

    The command interpreter -> If it's not the setup or configuration of the server, this is where I suspect the problem is. Is canReadLine() not doing what I want? I am just sending strings, so the line-oriented protocol is what I think I should be using. I do not undersand why, but if I chop two bytes off of the string, telnet works. The last two bytes are \r\n. Shouldn't simplified() remove those? If simplified doesn't work on a QByteArray why does this compile without errors in Qt Creator?

    @ void MainWindow::remoteCommandRead()
    QByteArray lineBuffer;
    QByteArray consoleString;
    QByteArray command;
    QList<QByteArray> commandList;

            lineBuffer = remoteControlClient->readLine();
            commandList = lineBuffer.split(' ');@

    The python client

    @import socket
    remote_sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
    server_address = ('address', port)

    Using telnet trhough PuTTy I discovered that there is some junk hanging around somewhere which I need to flush, but I don't know how much there is, where it is coming from or how to filter it out. When I enter a command using PuTTy the first time, the Qtserver side replies
    Unknown: ���� ����'������connect.
    The next time it gets Unknown: ���� ����'��'connect'
    Then Unknown: ��$connect
    And eventually it works and accepts the command Command: connect

    Any ideas about what is going on here?

    Many Thanks.

Log in to reply

Looks like your connection to Qt Forum was lost, please wait while we try to reconnect.