How to send messages to connected clients from server in Qt

Question

I know that how to send messages to the newly connected client whenever the QTcpServer newConnection is emitted. What I did is like this:

connect(serverConnection.tcpServer, &QTcpServer::newConnection, this, &ServerInterface::sendMessages);

void ServerInterface::sendMessages()
{
    QByteArray messagesToClients;
    QDataStream out(&messagesToClients, QIODevice::WriteOnly);
    QTcpSocket *clientConnection = serverConnection.tcpServer->nextPendingConnection();
    out << inputBox->toPlainText(); //get text from QTextEdit
    clientConnection->write(messagesToClients);
}

But what I want to do is whenever the send messages button is clicked in the server, it will send messages to currently connected clients. The code I provide can only send only one new message to the newly connected client. I have no idea of how to achieve what I want to do, so can someone provide me a way to do that? I am kind of new to Qt networking.

Thanks.

Answer 1

Just store your connections in container. Like this: in your ServerInterface h-file:

class ServerInterface {
// your stuff
public slots:
  void onClientConnected();
  void onClientDisconnected();
private:
  QVector<QTcpSocket *> mClients;
};

in your ServerInterface cpp-file :

  connect(serverConnection.tcpServer, SIGNAL(newConnection(), this, SLOT(onClientConnected());
void ServerInterface::onClientConnected() {
  auto newClient = serverConnection.tcpServer->nextPendingConnection();
  mClients->push_back( newClient );
  connect(newClient, SIGNAL(disconnected()), this, SLOT(onClientDisconnected());
}

void ServerInterface::onClientDisconnected() {
  if(auto client = dynamic_cast<QTcpSocket *>(sender()) {
   mClients->removeAll(client);
  }
void ServerInterface::sendMessages() {
  out << inputBox->toPlainText();
  for(auto &client : mClients) {
    client->write(messagesToClients);
  }
}