Sending message to choosen client

[apoyo]

@JonB Yes i have one server and many clients.clients send message by clickbutton and message goes to the server and server forwards it to client

[JonB]

@apoyo Good. Then follow what I wrote and implement it.

[apoyo]

i manage to do this according to @giusdbg idea,the socket->socketdescriptor in the server is write in ReadSocket function,but i have one problem ,that there is one requirements i want to abolish ; there is neccessity of sending the message by clicking button to be possible sending to this client

[apoyo]

@apoyo now i do this by this code but there is a problem that if i connect second client it disconnect ,without this code it work and it not disconnect ,but i need a possiblity of sending messages to chosen client without firstly send this message from chosen client,how to do this?

[JonB]

@apoyo
Please do not post screen shots of code, nobody can interact with them. Use the forum's Code tags (</> icon) to paste your code.

Do you think anybody can diagnose an issue from the code snippet you show here? How does it relate to multiple client connections?

Is this client-side or server-side code? It has ui in it so I guess client-side? If you have problems with multiple clients connecting or disconnecting then does it not seem likely that the issue is in the server code rather than client code?

[apoyo]

@JonB it is code in client side .If i pass this code into button it work and it not disconnect as i check minute ago

void messageprep::on_pushButton_3_clicked()
{
    QString strd="Welcome to the server";
    QString DoKogo;
    QString OdKogo;
    QDataStream welcome(socket);

    DoKogo=nazwa;
    OdKogo=nazwa;

    welcome<<strd<<DoKogo<<OdKogo;

}

[giusdbg]

@JonB @apoyo I don't know how to use sockets in QT.
But it seems to me that the problem is that the OP doesn't know how to accept multiple client connections on the same server.

Maybe this can help

https://wiki.qt.io/WIP-How_to_create_a_simple_chat_application

[apoyo]

@giusdbg said in Sending message to choosen client:

@JonB @apoyo I don't know how to use sockets in QT.
But it seems to me that the problem is that the OP doesn't know how to accept multiple client connections on the same server.

Maybe this can help

https://wiki.qt.io/WIP-How_to_create_a_simple_chat_application
maybe but if i send by button it works properlu

[giusdbg]

@apoyo At work, we sometimes get scolded because a customer complains that one of our jobs doesn't work.
Sometimes someone replies that it works fine on our system.
The somewhat irritated response is 'so let's tell our customer to come work on your system?'

[apoyo]

@giusdbg
i discover now that when i send a message from client and login into next client after that it disconnect :((

[JonB]

@apoyo

@JonB said in Sending message to choosen client:

If you have problems with multiple clients connecting or disconnecting then does it not seem likely that the issue is in the server code rather than client code?

[apoyo]

@JonB maybe

Does somebody after viewing this code can tell why it is disconnecting second client when he login when the first client have already sended message?

 m_server = new QTcpServer();

connect(this, &maineq::newMessage, this, &maineq::displayMessage);
    if(m_server->listen(QHostAddress::Any, 8080))
    {

        connect(m_server, &QTcpServer::newConnection, this, &maineq::newConnection);
        //cout<<"Serwer nasłuchuje";
    }
    else
    {
        // QMessageBox::critical(this,"QTCPServer",QString("Unable to start the server: %1.").arg(m_server->errorString()));
        exit(EXIT_FAILURE);
    }




    foreach (QTcpSocket* socket, connection_set)
    {
        socket->close();
        socket->deleteLater();
    }


    DB = QSqlDatabase::addDatabase("QSQLITE");
    DB.setDatabaseName("C:/Users/vkocz/OneDrive/Dokumenty/DB/logowanie.db");


    if(DB.open()){




        //  QMessageBox::information(this,"Connection","Database Connected Successfully");





    }
    else{


        //QMessageBox::information(this,"Not Connected","Database Connected UnSuccessfully");


    }
 //   m_server->close();
  //  m_server->deleteLater();


}
/*
maineq::~maineq(){




}*/
void maineq::newConnection(){

    while (m_server->hasPendingConnections())
        appendToSocketList(m_server->nextPendingConnection());
}


void maineq::appendToSocketList(QTcpSocket* socket){

    connection_set.insert(socket);
    connect(socket, &QTcpSocket::readyRead, this, &maineq::readSocket);
  connect(socket, &QTcpSocket::disconnected, this, &maineq::discardSocket);
    connect(socket, &QAbstractSocket::errorOccurred, this, &maineq::displayError);




}

[giusdbg]

@apoyo said in Sending message to choosen client:

Is there a reason for this?

foreach (QTcpSocket* socket, connection_set)
{
    socket->close();
    socket->deleteLater();
}

For the rest, I recommend looking at the example provided.

[apoyo]

@giusdbg
if i comment this part of code it still disconnected,so it is not reason for this

[giusdbg]

@apoyo Yes, but not being able to have an overview, I prefer to be perhaps erroneously suspicious.

Anyway, for example, you could put various 'connect' to disconnect, error, and similar events on sockets/descriptors and use QDebug to print when they are called.
If you have trouble viewing messages on a console, you can write to a log file (date hour minutes seconds text).

In desperate cases I've used wireshark to trace connections on the network with step by step debugging, but it's like shooting with 120 howitzer at a fly.
The trace of the events is better.

P.S. This is the client connection list that you will then need to process to send the same message to multiple clients,

connection_set

[apoyo]

@giusdbg now something works algothough i dont really why, i do debug and one line i delete

[giusdbg]

@apoyo If you're saying that debugging something works, but running the program usually causes the problem to return, it's often a sign that signal handling is incorrect or partial, or there are problems with object destruction (and using deleteLater() might stabilize the functioning).

The suggestion to look at the suggested example was also because it looks well set up and complete.

[giusdbg]

@apoyo One addition, if it works, it may be useful to use a telnet client program to try to connect to the server and send commands to it.