// TcpServerBase.h
#ifndef TCPSERVER_H
#define TCPSERVER_H
#include <QObject>
#include <QTcpServer>
#include <QTcpSocket>
class TcpServerBase : public QObject
{
  Q_OBJECT
public:
  explicit TcpServerBase(QObject *parent = nullptr);
  bool start(quint16 port);
  void stop();
signals:
  void clientConnected(QTcpSocket *socket);
  void clientDisconnected(QTcpSocket *socket);
  void readyRead(QTcpSocket *socket);
  void bytesWritten(QTcpSocket *socket, qint64 bytes);
  void error(QTcpSocket::SocketError socketError);
private slots:
  void onNewConnection();
  void onClientDisconnected();
  void onReadyRead();
  void onBytesWritten(qint64 bytes);
private:
  QTcpServer *m_server;
};
#endif // TCPSERVER_H
// tcpserver.cpp

#include "TcpServerBase.h"
TcpServerBase::TcpServerBase(QObject *parent) : QObject(parent), m_server(nullptr)
{
  m_server = new QTcpServer(this);
  connect(m_server, &QTcpServer::newConnection, this, &TcpServerBase::onNewConnection);
}
bool TcpServerBase::start(quint16 port)
{
  if (!m_server->listen(QHostAddress::Any, port)) {
    return false;
  }
  return true;
}
void TcpServerBase::stop()
{
  m_server->close();
  //qDeleteAll(m_clients);
  //m_clients.clear();
}
void TcpServerBase::onNewConnection()
{
  while (m_server->hasPendingConnections()) {
    QTcpSocket *client = m_server->nextPendingConnection();
    //m_clients.append(client);
    connect(client, &QTcpSocket::disconnected, this, &TcpServerBase::onClientDisconnected);
    connect(client, &QTcpSocket::readyRead, this, &TcpServerBase::onReadyRead);
    connect(client, &QTcpSocket::bytesWritten, this, &TcpServerBase::onBytesWritten);
    emit clientConnected(client);
  }
}
void TcpServerBase::onClientDisconnected()
{
  QTcpSocket *client = qobject_cast<QTcpSocket*>(sender());
  if (client) {
    //m_clients.removeOne(client);
    //client->deleteLater();
    emit clientDisconnected(client);
  }
}
void TcpServerBase::onReadyRead()
{
  QTcpSocket *client = qobject_cast<QTcpSocket*>(sender());
  if (client) {
    emit readyRead(client);
  }
}
void TcpServerBase::onBytesWritten(qint64 bytes)
{
  QTcpSocket *client = qobject_cast<QTcpSocket*>(sender());
  if (client) {
    emit bytesWritten(client, bytes);
  }
}