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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.
     **
     ** 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:
     ** http://www.trolltech.com/products/qt/opensource.html
     **
     ** If you are unsure which license is appropriate for your use, please
     ** review the following information:
     ** http://www.trolltech.com/products/qt/licensing.html or contact the
     ** sales department at sales@trolltech.com.
     **
     ** This file is provided AS IS with NO WARRANTY OF ANY KIND, INCLUDING THE
     ** WARRANTY OF DESIGN, MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
     **
     ****************************************************************************/

     #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());
     }