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# httpwindow.cpp Example File
network/http/httpwindow.cpp

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     #include <QtGui>
     #include <QtNetwork>

     #include "httpwindow.h"
     #include "ui_authenticationdialog.h"

     HttpWindow::HttpWindow(QWidget *parent)
         : QDialog(parent)
     {
     #ifndef QT_NO_OPENSSL
         urlLineEdit = new QLineEdit("https://");
     #else
         urlLineEdit = new QLineEdit("http://");
     #endif

         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(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(QHttpResponseHeader)),
                 this, SLOT(readResponseHeader(QHttpResponseHeader)));
         connect(http, SIGNAL(authenticationRequired(QString,quint16,QAuthenticator*)),
                 this, SLOT(slotAuthenticationRequired(QString,quint16,QAuthenticator*)));
     #ifndef QT_NO_OPENSSL
         connect(http, SIGNAL(sslErrors(QList<QSslError>)),
                 this, SLOT(sslErrors(QList<QSslError>)));
     #endif
         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 (fileName.isEmpty())
             fileName = "index.html";

         if (QFile::exists(fileName)) {
             if (QMessageBox::question(this, tr("HTTP"),
                                       tr("There already exists a file called %1 in "
                                          "the current directory. Overwrite?").arg(fileName),
                                       QMessageBox::Yes|QMessageBox::No, QMessageBox::No)
                 == QMessageBox::No)
                 return;
             QFile::remove(fileName);
         }

         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;
         }

         QHttp::ConnectionMode mode = url.scheme().toLower() == "https" ? QHttp::ConnectionModeHttps : QHttp::ConnectionModeHttp;
         http->setHost(url.host(), mode, url.port() == -1 ? 0 : url.port());

         if (!url.userName().isEmpty())
             http->setUser(url.userName(), url.password());

         httpRequestAborted = false;
         QByteArray path = QUrl::toPercentEncoding(url.path(), "!$&'()*+,;=:@/");
         if (path.isEmpty())
             path = "/";
         httpGetId = http->get(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 (requestId != httpGetId)
             return;
         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)
     {
         switch (responseHeader.statusCode()) {
         case 200:                   // Ok
         case 301:                   // Moved Permanently
         case 302:                   // Found
         case 303:                   // See Other
         case 307:                   // Temporary Redirect
             // these are not error conditions
             break;

         default:
             QMessageBox::information(this, tr("HTTP"),
                                      tr("Download failed: %1.")
                                      .arg(responseHeader.reasonPhrase()));
             httpRequestAborted = true;
             progressDialog->hide();
             http->abort();
         }
     }

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

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

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

     void HttpWindow::slotAuthenticationRequired(const QString &hostName, quint16, QAuthenticator *authenticator)
     {
         QDialog dlg;
         Ui::Dialog ui;
         ui.setupUi(&dlg);
         dlg.adjustSize();
         ui.siteDescription->setText(tr("%1 at %2").arg(authenticator->realm()).arg(hostName));

         if (dlg.exec() == QDialog::Accepted) {
             authenticator->setUser(ui.userEdit->text());
             authenticator->setPassword(ui.passwordEdit->text());
         }
     }

     #ifndef QT_NO_OPENSSL
     void HttpWindow::sslErrors(const QList<QSslError> &errors)
     {
         QString errorString;
         foreach (const QSslError &error, errors) {
             if (!errorString.isEmpty())
                 errorString += ", ";
             errorString += error.errorString();
         }

         if (QMessageBox::warning(this, tr("HTTP Example"),
                                  tr("One or more SSL errors has occurred: %1").arg(errorString),
                                  QMessageBox::Ignore | QMessageBox::Abort) == QMessageBox::Ignore) {
             http->ignoreSslErrors();
         }
     }
     #endif