Qt networking server

great88

I am trying to make a server application .
I looked at the threadedfortuneserver example that comes with QT 5 .
How do you keep a connection open until the client decides to disconnect ? I would like to
maintain a list of all open connections/sockets .

At the end of fortunethread.cpp , the code is :
tcpSocket.write(block);
tcpSocket.disconnectFromHost();
tcpSocket.waitForDisconnected();

So the socket is disconnected . If I comment out the last 2 lines , nothing is written to the client for some reason ?
How do I keep the connection open ? Do I use the socketDescriptor somehow ? I would try that but it seems to me
that the socket connection is gone .

AcerExtensa

Here is the simplest example to read and write on the same socket:

server.h
@
#include <QObject>
#include <QTcpServer>
#include <QTcpSocket>

class ExTCPServer : public QObject
{
Q_OBJECT
public:
explicit ExTCPServer(QObject *parent = 0);

private slots:
void new_connection();
void ready_read();

private:
QTcpServer * server;
QTcpSocket * sock;
};
@

server.cpp
@
#include "server.h"
#include <QDebug>

ExTCPServer::ExTCPServer(QObject *parent) :
QObject(parent)
{
this->server = new QTcpServer(this);
connect(this->server, SIGNAL(newConnection()), this, SLOT(new_connection()));
if(!this->server->listen(QHostAddress::Any, 4444))
{
qCritical() << "ERROR: " << this->server->errorString();
}
}

void ExTCPServer::new_connection()
{
if(!this->server->hasPendingConnections())return;
this->sock = this->server->nextPendingConnection();
connect(this->sock, SIGNAL(readyRead()),this, SLOT(ready_read()));
if(this->sock->bytesAvailable() > 0)
{
qDebug() << FUNCTION;
qDebug() << this->sock->readAll();
this->sock->write("I need more!");
}
}

void ExTCPServer::ready_read()
{
if(this->sock->bytesAvailable() > 0)
{
qDebug() << this->sock->readAll();
this->sock->write("I need more!");
}
}
@

client.h
@
#include <QObject>
#include <QTcpSocket>

class ExTCPClient : public QObject
{
Q_OBJECT
public:
explicit ExTCPClient(QObject *parent = 0);

private slots:
void connected();
void ready_read();

private:
QTcpSocket * sock;
};
@

client.cpp
@
#include "client.h"
#include <QHostAddress>
#include <QDebug>

ExTCPClient::ExTCPClient(QObject *parent) :
QObject(parent)
{
this->sock = new QTcpSocket(this);
connect(this->sock, SIGNAL(connected()), this, SLOT(connected()));
connect(this->sock, SIGNAL(readyRead()), this, SLOT(ready_read()));
this->sock->connectToHost(QHostAddress::Any, 4444);
}

void ExTCPClient::connected()
{
qDebug() << this->sock->write("read this!");
}

void ExTCPClient::ready_read()
{
if(this->sock->bytesAvailable() > 0)
{
qDebug() << this->sock->readAll();
this->sock->write("more data");
}
}
@

great88

OK , thanks for that . It seems straight forward enough . For the threadedfortuneserver example , why doesn't tcpSocket.write(block); write back to the client right away ? If I comment out the following lines :
tcpSocket.disconnectFromHost();
tcpSocket.waitForDisconnected();

then nothing happens . It seems those two lines are needed to do the write ?

great88

OK , I got the threadedfortuneserver code to work by
replacing
tcpSocket.write(block);
tcpSocket.disconnectFromHost();
tcpSocket.waitForDisconnected();

with
tcpSocket.write(block);
tcpSocket.waitForBytesWritten();

not sure I totally understand but interesting . If anyone has comments , please do write .