QTcpSocket网络通讯多客户端功能

首先声明此文章为学习Qt的网络通讯找的例子，仅供学习用，以下为自己总结，原作者的连接如下：GitHub - manfredipist/QTcpSocket: A simple Qt client-server TCP architecture to transfer data between peersA simple Qt client-server TCP architecture to transfer data between peers - GitHub - manfredipist/QTcpSocket: A simple Qt client-server TCP architecture to transfer data between peershttps://github.com/manfredipist/QTcpSocket

解决的问题：

在学习网络通讯时，Qt给你封装好了QTcpSocket类，来进行网络套接字通讯，经常会有需求进行一对多的功能，一台服务器，对多台客户端的开发，应用到实践中

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如何实现：

实现分为：1、客户端 Client

                  2、服务器端 Server

约定的数据格式头

fileType：attachment 、 message

QString("fileType:message,fileName:null,fileSize:%1;").arg(str.size()).toUtf8()

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代码块解析：

客户端 Client

.h文件

//1：读数据
void readSocket();
//2：断开连接
void discardSocket();
//3：错误连接
void displayError(QAbstractSocket::SocketError socketError);
//4：发送数据
void sendMessage();

.cpp文件

//1：连接
socket->connectToHost(QHostAddress::LocalHost,8080);
 
//2：读取数据在readyRead槽下
void MainWindow::readSocket()
{
    QByteArray buffer;
 
    QDataStream socketStream(socket);
    socketStream.setVersion(QDataStream::Qt_5_7);
 
    socketStream.startTransaction();
    socketStream >> buffer;
 
    QString header = buffer.mid(0,128);
    QString fileType = header.split(",")[0].split(":")[1];
 
    buffer = buffer.mid(128);
    if(fileType=="attachment"){
        //TODO
    }else if(fileType=="message"){
        //TODO
        QString message = QString("%1 :: %2").arg(socket->socketDescriptor()).arg(QString::fromStdString(buffer.toStdString()));
    }
}
 
//3：发送数据
void Mainindow::sendMessage()
{
    //1：组装数据
    QString str = ui->lineEdit_message->text();
 
    QDataStream socketStream(socket);
    socketStream.setVersion(QDataStream::Qt_5_7);
 
    QByteArray header;
    header.prepend(QString("fileType:message,fileName:null,fileSize:%1;").arg(str.size()).toUtf8());
    header.resize(128);
    //2：发送数据的包封装方式
    QByteArray byteArray = str.toUtf8();
    byteArray.prepend(header);
    //3：数据发送
    socketStream << byteArray;
}

服务器端 Server

1：监听端口

m_server = new QTcpServer();
m_server->listen(QHostAddress::Any, 8080)

2：当有客户端client连接时，发出newConnection 信号，由于要进行多客户端功能，得把客户端给存起来

void MainWindow::appendToSocketList(QTcpSocket* socket)
{
    connection_set.insert(socket);
    connect(socket, &QTcpSocket::readyRead, this, &MainWindow::readSocket);
    connect(socket, &QTcpSocket::disconnected, this, &MainWindow::discardSocket);
    connect(socket, SIGNAL(error(QAbstractSocket::SocketError)), this, SLOT(displayError(QAbstractSocket::SocketError)));
    ui->comboBox_receiver->addItem(QString::number(socket->socketDescriptor()));
    displayMessage(QString("INFO :: Client with sockd:%1 has just entered the room").arg(socket->socketDescriptor()));
}
 
void MainWindow::newConnection()
{
    while (m_server->hasPendingConnections())
        appendToSocketList(m_server->nextPendingConnection());
}

3：readSocket()功能与客户端client一致，唯一区别，打印的时候，带上了客户端连接的唯一标识：socket->socketDescriptor

4：reinterpret_cast<>用法将sender()转换成socket对象

reinterpret_cast与static_cast_云之舟_的博客-CSDN博客_reinterpret_cast

5：分发消息的机制

void MainWindow::sendMessage(QTcpSocket* socket)
{
    if(socket)
    {
        if(socket->isOpen())
        {
            QString str = ui->lineEdit_message->text();
 
            QDataStream socketStream(socket);
            socketStream.setVersion(QDataStream::Qt_5_7);
 
            QByteArray header;
            header.prepend(QString("fileType:message,fileName:null,fileSize:%1;").arg(str.size()).toUtf8());
            header.resize(128);
 
            QByteArray byteArray = str.toUtf8();
            byteArray.prepend(header);
 
            socketStream.setVersion(QDataStream::Qt_5_7);
            socketStream << byteArray;
        }
        else
            QMessageBox::critical(this,"QTCPServer","Socket doesn't seem to be opened");
    }
    else
        QMessageBox::critical(this,"QTCPServer","Not connected");
}
 
 
void MainWindow::on_pushButton_sendMessage_clicked()
{
    QString receiver = ui->comboBox_receiver->currentText();
 
    if(receiver=="Broadcast")
    {
        foreach (QTcpSocket* socket,connection_set)
        {
            sendMessage(socket);
        }
    }
    else
    {
        foreach (QTcpSocket* socket,connection_set)
        {
            if(socket->socketDescriptor() == receiver.toLongLong())
            {
                sendMessage(socket);
                break;
            }
        }
    }
    ui->lineEdit_message->clear();
}