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httpwindow.cpp Example File
^{network/http/httpwindow.cpp}

 /****************************************************************************
 **
 ** Copyright (C) 2004-2007 Trolltech ASA. All rights reserved.
 **
 ** This file is part of the example classes of the Qt Toolkit.
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 ** This file may be used under the terms of the GNU General Public
 ** License version 2.0 as published by the Free Software Foundation
 ** and appearing in the file LICENSE.GPL included in the packaging of
 ** this file.  Please review the following information to ensure GNU
 ** General Public Licensing requirements will be met:
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 ** review the following information:
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 ** This file is provided AS IS with NO WARRANTY OF ANY KIND, INCLUDING THE
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 ****************************************************************************/

 #include <QtGui>
 #include <QtNetwork>

 #include "httpwindow.h"

 HttpWindow::HttpWindow(QWidget *parent)
     : QDialog(parent)
 {
     urlLineEdit = new QLineEdit("http://www.ietf.org/iesg/1rfc_index.txt");

     urlLabel = new QLabel(tr("&URL:"));
     urlLabel->setBuddy(urlLineEdit);
     statusLabel = new QLabel(tr("Please enter the URL of a file you want to "
                                 "download."));

     downloadButton = new QPushButton(tr("Download"));
     downloadButton->setDefault(true);
     quitButton = new QPushButton(tr("Quit"));
     quitButton->setAutoDefault(false);

     buttonBox = new QDialogButtonBox;
     buttonBox->addButton(downloadButton, QDialogButtonBox::ActionRole);
     buttonBox->addButton(quitButton, QDialogButtonBox::RejectRole);

     progressDialog = new QProgressDialog(this);

     http = new QHttp(this);

     connect(urlLineEdit, SIGNAL(textChanged(const QString &)),
             this, SLOT(enableDownloadButton()));
     connect(http, SIGNAL(requestFinished(int, bool)),
             this, SLOT(httpRequestFinished(int, bool)));
     connect(http, SIGNAL(dataReadProgress(int, int)),
             this, SLOT(updateDataReadProgress(int, int)));
     connect(http, SIGNAL(responseHeaderReceived(const QHttpResponseHeader &)),
             this, SLOT(readResponseHeader(const QHttpResponseHeader &)));
     connect(progressDialog, SIGNAL(canceled()), this, SLOT(cancelDownload()));
     connect(downloadButton, SIGNAL(clicked()), this, SLOT(downloadFile()));
     connect(quitButton, SIGNAL(clicked()), this, SLOT(close()));

     QHBoxLayout *topLayout = new QHBoxLayout;
     topLayout->addWidget(urlLabel);
     topLayout->addWidget(urlLineEdit);

     QVBoxLayout *mainLayout = new QVBoxLayout;
     mainLayout->addLayout(topLayout);
     mainLayout->addWidget(statusLabel);
     mainLayout->addWidget(buttonBox);
     setLayout(mainLayout);

     setWindowTitle(tr("HTTP"));
     urlLineEdit->setFocus();
 }

 void HttpWindow::downloadFile()
 {
     QUrl url(urlLineEdit->text());
     QFileInfo fileInfo(url.path());
     QString fileName = fileInfo.fileName();

     if (QFile::exists(fileName)) {
         QMessageBox::information(this, tr("HTTP"),
                                  tr("There already exists a file called %1 in "
                                     "the current directory.")
                                  .arg(fileName));
         return;
     }

     file = new QFile(fileName);
     if (!file->open(QIODevice::WriteOnly)) {
         QMessageBox::information(this, tr("HTTP"),
                                  tr("Unable to save the file %1: %2.")
                                  .arg(fileName).arg(file->errorString()));
         delete file;
         file = 0;
         return;
     }

     http->setHost(url.host(), url.port() != -1 ? url.port() : 80);
     if (!url.userName().isEmpty())
         http->setUser(url.userName(), url.password());

     httpRequestAborted = false;
     httpGetId = http->get(url.path(), file);

     progressDialog->setWindowTitle(tr("HTTP"));
     progressDialog->setLabelText(tr("Downloading %1.").arg(fileName));
     downloadButton->setEnabled(false);
 }

 void HttpWindow::cancelDownload()
 {
     statusLabel->setText(tr("Download canceled."));
     httpRequestAborted = true;
     http->abort();
     downloadButton->setEnabled(true);
 }

 void HttpWindow::httpRequestFinished(int requestId, bool error)
 {
     if (httpRequestAborted) {
         if (file) {
             file->close();
             file->remove();
             delete file;
             file = 0;
         }

         progressDialog->hide();
         return;
     }

     if (requestId != httpGetId)
         return;

     progressDialog->hide();
     file->close();

     if (error) {
         file->remove();
         QMessageBox::information(this, tr("HTTP"),
                                  tr("Download failed: %1.")
                                  .arg(http->errorString()));
     } else {
         QString fileName = QFileInfo(QUrl(urlLineEdit->text()).path()).fileName();
         statusLabel->setText(tr("Downloaded %1 to current directory.").arg(fileName));
     }

     downloadButton->setEnabled(true);
     delete file;
     file = 0;
 }

 void HttpWindow::readResponseHeader(const QHttpResponseHeader &responseHeader)
 {
     if (responseHeader.statusCode() != 200) {
         QMessageBox::information(this, tr("HTTP"),
                                  tr("Download failed: %1.")
                                  .arg(responseHeader.reasonPhrase()));
         httpRequestAborted = true;
         progressDialog->hide();
         http->abort();
         return;
     }
 }

 void HttpWindow::updateDataReadProgress(int bytesRead, int totalBytes)
 {
     if (httpRequestAborted)
         return;

     progressDialog->setMaximum(totalBytes);
     progressDialog->setValue(bytesRead);
 }

 void HttpWindow::enableDownloadButton()
 {
     downloadButton->setEnabled(!urlLineEdit->text().isEmpty());
 }