如何以几秒间隔多次使用 QTcpSocket 实例

How to use QTcpSocket instance multiple times with couple second intervals?

本文关键字：实例 QTcpSocket 几秒      更新时间：2023-10-16

我必须用QTcpSocket多次重复相同的请求，间隔几秒钟。简单的任务，但我无法让它只处理一个对象实例。如何使用同一 QTcpSocket 实例再次连接到服务器？我已经尝试了重置（），恢复（），flush（），open（）许多不同的组合，它什么也没做。我无法第二次连接到主机（） ...

您所要做的就是connectToHost()，使用连接，然后disconnectFromHost()。就是这样。仅此而已，仅此而已。

下面的示例说明了客户端和服务器套接字实例的重用。服务器实例保存在仅在必要时增长的池中。它是为 Qt 5 编写的，使用 C++11。

// https://github.com/KubaO/stackoverflown/tree/master/questions/multisocket-22726075
#include <QtNetwork>
class EchoServer : public QTcpServer
{
   QStack<QTcpSocket*> m_pool;
   void incomingConnection(qintptr descr) Q_DECL_OVERRIDE {
      if (m_pool.isEmpty()) {
         auto s = new QTcpSocket(this);
         QObject::connect(s, &QTcpSocket::readyRead, s, [s]{
            s->write(s->readAll());
         });
         QObject::connect(s, &QTcpSocket::disconnected, this, [this, s]{
            m_pool.push(s);
         });
         m_pool.push(s);
      }
      m_pool.pop()->setSocketDescriptor(descr, QTcpSocket::ConnectedState);
   }
public:
   ~EchoServer() { qDebug() << "pool size:" << m_pool.size(); }
};
void setupEchoClient(QTcpSocket & sock)
{
   static const char kByteCount[] = "byteCount";
   QObject::connect(&sock, &QTcpSocket::connected, [&sock]{
      auto byteCount = 64 + qrand() % 65536;
      sock.setProperty(kByteCount, byteCount);
      sock.write(QByteArray(byteCount, 'x2A'));
   });
   QObject::connect(&sock, &QTcpSocket::readyRead, [&sock]{
      auto byteCount = sock.property(kByteCount).toInt();
      if (byteCount) {
         auto read = sock.read(sock.bytesAvailable()).size();
         byteCount -= read;
      }
      if (byteCount <= 0) sock.disconnectFromHost();
      sock.setProperty(kByteCount, byteCount);
   });
}
int main(int argc, char *argv[])
{
   QCoreApplication a(argc, argv);
   QHostAddress addr("127.0.0.1");
   quint16 port = 5050;
   EchoServer server;
   if (! server.listen(addr, port)) qFatal("can't listen");
   QTcpSocket clientSocket;
   setupEchoClient(clientSocket);
   auto connectsLeft = 20;
   auto connector = [&clientSocket, &addr, port, &connectsLeft]{
      if (connectsLeft--) {
         qDebug() << "connecting" << connectsLeft;
         clientSocket.connectToHost(addr, port);
      } else
         qApp->quit();
   };
   // reconnect upon disconnection
   QObject::connect(&clientSocket, &QTcpSocket::disconnected, connector);
   // initiate first connection
   connector();
   return a.exec();
}
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