I found within the Web a good example to implement an Http Proxy.
It works great, but the problem is that it is single threaded.
I tried to change it to a multithread version, but for some odd reason the code fires a segfault.
The original single thread version follows:
Qt Code: 
  1. /*
  2.  
  3. */
  4.  
  5. #include "webproxy.h"
  6. #include <QtNetwork>
  7. #include <QMessageBox>
  8. #include <QtGui>
  9. #include <QHash>
  10.  
  11.  
  12. WebProxy::WebProxy(QObject *parent,int port): QObject(parent)
  13.  
  14.     {
  15.  
  16.         QTcpServer *proxyServer = new QTcpServer(this);
  17.         if (!proxyServer->listen(QHostAddress::Any, port)) {
  18.            emit error(1);
  19.  
  20.             return;
  21.         }
  22.  
  23.         connect(proxyServer, SIGNAL(newConnection()), this, SLOT(manageQuery()));
  24.         qDebug() << "Proxy server running at port" << proxyServer->serverPort();
  25.  
  26.  
  27.     }
  28.  
  29. void WebProxy::setAddress(const QHostAddress &a, int port)
  30. {
  31.     proxyAddress = a;
  32.     proxyPort    = port;
  33.     port = port < 0 ? 8081 : port;
  34.  
  35.  
  36. }
  37.  
  38. void WebProxy::manageQuery() {
  39.         QTcpServer *proxyServer = qobject_cast<QTcpServer*>(sender());
  40.         QTcpSocket *socket = proxyServer->nextPendingConnection();
  41.         connect(socket, SIGNAL(readyRead()), this, SLOT(processQuery()));
  42.         connect(socket, SIGNAL(disconnected()), socket, SLOT(deleteLater()));
  43.         qDebug()<<"New connection started..."<<socket->peerAddress();
  44.     }
  45. QUrl WebProxy::getUrl(QList<QByteArray > &entries)
  46.    {
  47.  
  48.        QByteArray method = entries.value(0);
  49.        QByteArray address = entries.value(1);
  50.        QByteArray version = entries.value(2);
  51.  
  52.  
  53.        QUrl url = QUrl::fromEncoded(address);
  54.        if (!url.isValid()) {
  55.  
  56.            qWarning() << "Invalid URL:" << url;
  57.            return QString();
  58.        }
  59.        return url;
  60.    }
  61.  
  62.   void WebProxy::processQuery() {
  63.  
  64.         QTcpSocket *socket = qobject_cast<QTcpSocket*>(sender());
  65.         QByteArray requestData = socket->readAll();
  66.  
  67.         int pos = requestData.indexOf("\r\n");
  68.  
  69.         QByteArray requestLine = requestData.left(pos);
  70.         requestData.remove(0, pos + 2);
  71.  
  72.         QList<QByteArray> entries = requestLine.split(' ');
  73.         QByteArray method         = entries.value(0);
  74.         QByteArray address         = entries.value(1);
  75.         QByteArray version         = entries.value(2);
  76.  
  77.         QByteArray auth;
  78.         QByteArray authMethod;
  79.  
  80.         QUrl url = QUrl::fromEncoded(address);
  81.         if (!url.isValid()) {
  82.             qWarning() << "Invalid URL:" << url;
  83.             socket->disconnectFromHost();
  84.             return;
  85.         }
  86.  
  87.         QString host              = url.host();
  88.  
  89.         int port = (url.port() <= 0) ? 80 : url.port();
  90.         QByteArray req = url.encodedPath();
  91.         if (url.hasQuery())
  92.             req.append('?').append(url.encodedQuery());
  93.  
  94.         requestLine = method + " " + req + " " + version + "\r\n";
  95.  
  96.  
  97.         QString key = host + ':' + QString::number(port);
  98.         QTcpSocket *proxySocket = socket->findChild<QTcpSocket*>(key);
  99.         if (proxySocket) {
  100.             proxySocket->setObjectName(key);
  101.             proxySocket->setProperty("url", url);
  102.             proxySocket->setProperty("requestData", requestData);
  103.             proxySocket->write(requestData);
  104.         } else {
  105.             proxySocket = new QTcpSocket(socket);
  106.             proxySocket->setObjectName(key);
  107.             proxySocket->setProperty("url", url);
  108.             proxySocket->setProperty("requestData", requestData);
  109.             connect(proxySocket, SIGNAL(connected()), this, SLOT(sendRequest()));
  110.             connect(proxySocket, SIGNAL(readyRead()), this, SLOT(transferData()));
  111.             connect(proxySocket, SIGNAL(disconnected()), this, SLOT(closeConnection()));
  112.             connect(proxySocket, SIGNAL(error(QAbstractSocket::SocketError)), this, SLOT(closeConnection()));
  113.             proxySocket->connectToHost(host, port);
  114.         }
  115.     }
  116.  
  117. void WebProxy::sendRequest() {
  118.         QTcpSocket *proxySocket = qobject_cast<QTcpSocket*>(sender());
  119.         QByteArray requestData = proxySocket->property("requestData").toByteArray();
  120.         proxySocket->write(requestData);
  121.     }
  122.  
  123. void WebProxy::transferData() {
  124.  
  125.  
  126.         QTcpSocket *proxySocket = qobject_cast<QTcpSocket*>(sender());
  127.         QByteArray data = proxySocket->readAll();
  128.         QString host = proxySocket->peerAddress().toString();
  129.  
  130.         QTcpSocket *socket = qobject_cast<QTcpSocket*>(proxySocket->parent());
  131.         socket->write(data);
  132.  
  133.     }
  134.  
  135. void WebProxy::closeConnection() {
  136.         QTcpSocket *proxySocket = qobject_cast<QTcpSocket*>(sender());
  137.         if (proxySocket) {
  138.             QTcpSocket *socket = qobject_cast<QTcpSocket*>(proxySocket->parent());
  139.             if (socket)
  140.                 socket->disconnectFromHost();
  141.             if (proxySocket->error() != QTcpSocket::RemoteHostClosedError)
  142.                 qWarning() << "Error for:" << proxySocket->property("url").toUrl()
  143.                         << proxySocket->errorString();
  144.             proxySocket->deleteLater();;
  145.         }
  146.     }
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I call "new WebProxy " in the main.
In the multithreaded version, I put all functions from manageQuery() inside a new threaded Class. But when a connection start, I got a segfault.
Any help appreciated.
Does anybody know