Example Analysis of multithreading on Qt Server

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This example uses only two threads, one for listening for new connections and one for handling client events that have established connections (here a thread pool can be used to improve performance). Message receiving adds a simple subpacket mechanism. The first four bytes of each message store the uint32_t type, which refers to the entire length of the message, so that each message can be well distinguished. The code is somewhat imprecise in many details, for reference only.

/ / tcpserver.hclass CClientSocket;class CTcpServer final: public QTcpServer {Q_OBJECTpublic: explicit CTcpServer (QObject * parent = nullptr); virtual ~ CTcpServer () override; void Listen (int _ iPort); void Nortify (const QByteArray & _ csMessage); protected: virtual void incomingConnection (qintptr socketDescriptor) override; virtual void timerEvent (QTimerEvent * event) override;public slots: void SLOT_ClientDisconnect (); private: void _ PackageMessage (QByteArray & _ baMsg); private: QList masked lstSocket; / /

< 连接的客户端 QThread * m_pEventThd; ///< 事件线程};// tcpserver.cppCTcpServer::CTcpServer(QObject *parent) : QTcpServer(parent), m_pEventThd(new QThread()){ m_lstSocket.clear();}CTcpServer::~CTcpServer(){}void CTcpServer::Listen(int _iPort){ this->

Listen (QHostAddress::Any, static_cast (_ iPort)); start (); QObject::startTimer (5 * 1000);} void CTcpServer::Nortify (const QByteArray & _ csMessage) {QByteArray baSendMsg = _ csMessage; _ PackageMessage (baSendMsg); for (auto pClientSocket: m_lstSocket) {pClientSocket- > SendMsg (baSendMsg);} QThread::msleep (50);} void CTcpServer::incomingConnection (qintptr socketDescriptor) {qDebug () setSocketDescriptor (_ iFd) Connect (this, SIGNAL (error (QAbstractSocket::SocketError)), this, SLOT (SLOT_SocketError (QAbstractSocket::SocketError)); connect (this, & QTcpSocket::readyRead, this, & CClientSocket::SLOT_ReadyRead); connect (this, & QTcpSocket::disconnected, this, & CClientSocket::SLOT_Disconnect); m_iOldResponseTimeStamp = QDateTime::currentDateTime (). ToSecsSinceEpoch ();} CClientSocket::~CClientSocket () {this- > close () QDebug () moveToThread (_ pThread); QMetaObject::invokeMethod (this, & CClientSocket::_StartCheckTimer);} void CClientSocket::SendMsg (const QByteArray& _ baMessage) {QMetaObject::invokeMethod (this, "_ SendMessage", Q_ARG (const QByteArray&, _ baMessage)) } void CClientSocket::timerEvent (QTimerEvent * event) {if (m_iTimeId = = event- > timerId ()) {if (abs (QDateTime::currentSecsSinceEpoch ()-m_iOldResponseTimeStamp) > 60) {this- > disconnectFromHost ();} void CClientSocket::_DeInitSocket () {this- > close (); QObject::killTimer (m_iTimeId); m_iTimeId = 0 } void CClientSocket::_UpdateHeartTime () {m_iOldResponseTimeStamp = QDateTime::currentDateTime (). ToSecsSinceEpoch ();} void CClientSocket::_StartCheckTimer () {qDebug () isWritable () {this- > write (_ baMessage); this- > flush ();}} void CClientSocket::SLOT_ReadyRead () {char cBuffer [read _ MAX_SIZE]; qint64 iReadSize = 0; QByteArray baNewCache; do {iReadSize = this- > read (cBuffer, READ_MAX_SIZE) If (iReadSize =-1) / /

< 网络异常 { qDebug() peerAddress().toString()) .arg(this->

PeerPort (); this- > SLOT_Disconnect (); return;} if (iReadSize! = 0) {baNewCache.append (cBuffer, static_cast (iReadSize));}} while (iReadSize! = 0); if (m_tMsgCache.baPacket.size ()! = 0) {baNewCache = m_tMsgCache.baPacket + baNewCache } while (baNewCache.size () > 0) {if (baNewCache.size () > 4) {uint32_t iSize; if (m_tMsgCache.iSize = = 0) {QByteArray baSize = baNewCache.mid (0,4);:: memcpy (& iSize, baSize.data (), sizeof (iSize)) ISize =: ntohl (iSize);} else {iSize = MsgCache.iSize;} if (baNewCache.size () > = static_cast (iSize)) / / decompose a complete message packet {m_tMsgCache.baPacket = baNewCache.mid (4, static_cast (iSize-4)) / Action: push to the execution thread queue / / Push pHandleMessageThd-> Push (m_tMsgCache.baPacket); / / reset cache status m_tMsgCache.Clear (); / / detect the next new message packet baNewCache = baNewCache.mid (static_cast (iSize)) } else {m_tMsgCache.iSize = iSize; m_tMsgCache.baPacket = baNewCache; break;}} else {/ / there is no complete 4-byte length value m_tMsgCache.iSize = 0; m_tMsgCache.baPacket = baNewCache; break }} this- > _ UpdateHeartTime ();} void CClientSocket::SLOT_SocketError (QAbstractSocket::SocketError _ eError) {qDebug () peerAddress (). ToString () .arg (this- > peerPort ()). Arg (_ eError); _ DeInitSocket (); emit SIGNAL_Disconneted ();} void CClientSocket::SLOT_Disconnect () {qDebug ()