Qt 5.11 | Qt Network | Network Chat Example | peermanager.cpp Example File

Qt 5.11.3 Reference Documentation

# peermanager.cpp Example File

network-chat/peermanager.cpp

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      #include <QtNetwork>

      #include "client.h"
      #include "connection.h"
      #include "peermanager.h"

      static const qint32 BroadcastInterval = 2000;
      static const unsigned broadcastPort = 45000;

      PeerManager::PeerManager(Client *client)
          : QObject(client)
      {
          this->client = client;

          QStringList envVariables;
          envVariables << "USERNAME" << "USER" << "USERDOMAIN"
                       << "HOSTNAME" << "DOMAINNAME";

          QProcessEnvironment environment = QProcessEnvironment::systemEnvironment();
          foreach (QString string, envVariables) {
              if (environment.contains(string)) {
                  username = environment.value(string).toUtf8();
                  break;
              }
          }

          if (username.isEmpty())
              username = "unknown";

          updateAddresses();
          serverPort = 0;

          broadcastSocket.bind(QHostAddress::Any, broadcastPort, QUdpSocket::ShareAddress
                               | QUdpSocket::ReuseAddressHint);
          connect(&broadcastSocket, SIGNAL(readyRead()),
                  this, SLOT(readBroadcastDatagram()));

          broadcastTimer.setInterval(BroadcastInterval);
          connect(&broadcastTimer, SIGNAL(timeout()),
                  this, SLOT(sendBroadcastDatagram()));
      }

      void PeerManager::setServerPort(int port)
      {
          serverPort = port;
      }

      QByteArray PeerManager::userName() const
      {
          return username;
      }

      void PeerManager::startBroadcasting()
      {
          broadcastTimer.start();
      }

      bool PeerManager::isLocalHostAddress(const QHostAddress &address)
      {
          foreach (QHostAddress localAddress, ipAddresses) {
              if (address == localAddress)
                  return true;
          }
          return false;
      }

      void PeerManager::sendBroadcastDatagram()
      {
          QByteArray datagram(username);
          datagram.append('@');
          datagram.append(QByteArray::number(serverPort));

          bool validBroadcastAddresses = true;
          foreach (QHostAddress address, broadcastAddresses) {
              if (broadcastSocket.writeDatagram(datagram, address,
                                                broadcastPort) == -1)
                  validBroadcastAddresses = false;
          }

          if (!validBroadcastAddresses)
              updateAddresses();
      }

      void PeerManager::readBroadcastDatagram()
      {
          while (broadcastSocket.hasPendingDatagrams()) {
              QHostAddress senderIp;
              quint16 senderPort;
              QByteArray datagram;
              datagram.resize(broadcastSocket.pendingDatagramSize());
              if (broadcastSocket.readDatagram(datagram.data(), datagram.size(),
                                               &senderIp, &senderPort) == -1)
                  continue;

              QList<QByteArray> list = datagram.split('@');
              if (list.size() != 2)
                  continue;

              int senderServerPort = list.at(1).toInt();
              if (isLocalHostAddress(senderIp) && senderServerPort == serverPort)
                  continue;

              if (!client->hasConnection(senderIp)) {
                  Connection *connection = new Connection(this);
                  emit newConnection(connection);
                  connection->connectToHost(senderIp, senderServerPort);
              }
          }
      }

      void PeerManager::updateAddresses()
      {
          broadcastAddresses.clear();
          ipAddresses.clear();
          foreach (QNetworkInterface interface, QNetworkInterface::allInterfaces()) {
              foreach (QNetworkAddressEntry entry, interface.addressEntries()) {
                  QHostAddress broadcastAddress = entry.broadcast();
                  if (broadcastAddress != QHostAddress::Null && entry.ip() != QHostAddress::LocalHost) {
                      broadcastAddresses << broadcastAddress;
                      ipAddresses << entry.ip();
                  }
              }
          }
      }