MyClient.cpp

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// ======================================================================
//  MyClient.cpp
// ======================================================================
//                   This file is a part of the book 
//             "Qt 5.10 Professional programming with C++"
//                       http://qt-book.com
// ======================================================================
//  Copyright (c) 2017 by Max Schlee
// ======================================================================

#include <QtWidgets>
#include <QtGui>
#include "MyClient.h"

// ----------------------------------------------------------------------
MyClient::MyClient(const QString& strHost, 
                   int            nPort, 
                   QWidget*       pwgt /*=0*/
                  ) : QWidget(pwgt)
                    , m_nNextBlockSize(0)
{
    m_pTcpSocket = new QTcpSocket(this);

    m_pTcpSocket->connectToHost(strHost, nPort);
    connect(m_pTcpSocket, SIGNAL(connected()), SLOT(slotConnected()));
    connect(m_pTcpSocket, SIGNAL(readyRead()), SLOT(slotReadyRead()));
    connect(m_pTcpSocket, SIGNAL(error(QAbstractSocket::SocketError)),
            this,         SLOT(slotError(QAbstractSocket::SocketError))
           );

    m_ptxtInfo  = new QTextEdit;
    m_ptxtInput = new QLineEdit;

    connect(m_ptxtInput, SIGNAL(returnPressed()), 
            this,        SLOT(slotSendToServer())
           );
    m_ptxtInfo->setReadOnly(true);

    QPushButton* pcmd = new QPushButton("&Send");
    connect(pcmd, SIGNAL(clicked()), SLOT(slotSendToServer()));

    //Layout setup
    QVBoxLayout* pvbxLayout = new QVBoxLayout;    
    pvbxLayout->addWidget(new QLabel("<H1>Client</H1>"));
    pvbxLayout->addWidget(m_ptxtInfo);
    pvbxLayout->addWidget(m_ptxtInput);
    pvbxLayout->addWidget(pcmd);
    setLayout(pvbxLayout);
}

// ----------------------------------------------------------------------
void MyClient::slotReadyRead()
{
    QDataStream in(m_pTcpSocket);
    in.setVersion(QDataStream::Qt_5_3);
    for (;;) {
        if (!m_nNextBlockSize) {
            if (m_pTcpSocket->bytesAvailable() < (int)sizeof(quint16)) {
                break;
            }
            in >> m_nNextBlockSize;
        }

        if (m_pTcpSocket->bytesAvailable() < m_nNextBlockSize) {
            break;
        }
        QTime   time;
        QString str;
        in >> time >> str;

        m_ptxtInfo->append(time.toString() + " " + str);
        m_nNextBlockSize = 0;
    }
}

// ----------------------------------------------------------------------
void MyClient::slotError(QAbstractSocket::SocketError err)
{
    QString strError = 
        "Error: " + (err == QAbstractSocket::HostNotFoundError ? 
                     "The host was not found." :
                     err == QAbstractSocket::RemoteHostClosedError ? 
                     "The remote host is closed." :
                     err == QAbstractSocket::ConnectionRefusedError ? 
                     "The connection was refused." :
                     QString(m_pTcpSocket->errorString())
                    );
    m_ptxtInfo->append(strError);
}

// ----------------------------------------------------------------------
void MyClient::slotSendToServer()
{
    QByteArray  arrBlock;
    QDataStream out(&arrBlock, QIODevice::WriteOnly);
    out.setVersion(QDataStream::Qt_5_3);
    out << quint16(0) << QTime::currentTime() << m_ptxtInput->text();

    out.device()->seek(0);
    out << quint16(arrBlock.size() - sizeof(quint16));

    m_pTcpSocket->write(arrBlock);
    m_ptxtInput->setText("");
}

// ------------------------------------------------------------------
void MyClient::slotConnected()
{
    m_ptxtInfo->append("Received the connected() signal");
}