wrong syntax or QTcpSocket problem?

[vito49]

Hello, the first QT program i'm writing is a NNTP program to post binaries.
Up to now I managed to connect with the server and to read its response to several commands I give (like 'POST' and 'HELP'). So far so good.
Of course I first try to send a small message with only text in the body, and if this works I can focus on sending binaries.

But I have a problem I don't understand ... when I try to send that message I need to do it as in this code:


QString t;
QString CRLF("\n");
t.clear();
t.append("From: " + userName + + CRLF);
t.append("Newsgroups: " + (comboBox->currentText()) + CRLF);
/// and so on with a few other commands more

tcpSocket->write(t.toAscii().data()); //this writes the data to the socket


With this code the server returns a '500', meaning it doesn't understand the commands.

Now I found out that if I remove the 'CRLF' the newsserver doesn't complain but of course nothing is posted. And I know from an existing program the cr/lf must be there. Here's a snippet from that c-program I sometimes use, called 'newspost' (but this text based program is no longer maintained for Linux).



buff = buff_add(buff, "From: %s\r\n", data->from->data);
buff = buff_add(buff, "Newsgroups: %s\r\n", data->newsgroup->data);
buff = buff_add(buff, "Subject: %s\r\n", subject);
buff = buff_add(buff, "User-Agent: %s\r\n", USER_AGENT);
// and so on ...


For the CRLF I tried "\r\n" too ... with the same result.
Here's the routine to read the server, it works without problems.



void myQtApp::readHost()
{
QMessageBox msgWarn;
QString s;
QString t;
s.clear();
t.clear();
s=tcpSocket->readLine();

switch(s.left(3).toInt()){
case 100:
t.append("request for help granted");
break;
case 200:
t.append("server ready to receive");
break;
case 211:
t.append("newsgroup valid and selected");
break;
case 221:
t.append("no data follows");
break;
case 340:
postFiles();
break;
case 500:
t.append("wrong command");
break;
case 501:
t.append("wrong syntax after command");
break;
default:
t.append(s.left(3));
// temporarily messageBox for control
msgWarn.warning(this, "server says", s.toAscii().data(), QMessageBox::Ok);
break;
}

label_status->setText(t);
}



It puzzles me that the server doesn't accept a carriage return ... well, to be honest I do believe it's my code that is in error, not the server. Or is it something with the tcpSocket?
I'm stuck :(

All info welcome. Thanks in advance for your reply.

[mcosta]

Are you sure you're received bytes you need to readLine()?

Where do you set the code you check?


s.left(3).toInt()

[vito49]

Are you sure you're received bytes you need to readLine()?

Where do you set the code you check?


s.left(3).toInt()

Thanks for your reply.
But I'm not sure I understand what you mean ...
To read what the server says I use this signal/slot:


connect(tcpSocket, SIGNAL(readyRead()),this,SLOT(readHost()));


Every time the server sends a message the readHost() function is called. Here's a piece of code:


switch(s.left(3).toInt()){
case 100:
t.append("request for help granted");
break;
case 200:
t.append("server ready to receive");
break;

I only need the first 3 characters to determine the command it sends, so I strip everything from the message except the first 3 characters.

When I send "From: Vito" nothing happens, that seems normal to me because the string is not terminated by a "\n", but when I add a cr/lf the server responds with a '500' meaning it doesn't understand the message sent.

Maybe I don't use the right commands, that's possible, I got them from an older c-program and that worked fine a while ago on the same newsserver.

[vito49]

Are you sure you're received bytes you need to readLine()?

Where do you set the code you check?


s.left(3).toInt()

OK, there seems to be no problem with the socket but a misunderstanding of commands for the server. When I send "post\n" the newsserver doest complain, it sends a '340' followed by a suggested ID to use for my post. I now derived all commands from the server with 'help\n" command and they are ALL different from the ones I had. Strange but true.

I have to dig into these new commands now :rolleyes: