httpwindow.cpp Example File

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#include <QtWidgets> #include <QtNetwork> #include <QUrl> #include "httpwindow.h" #include "ui_authenticationdialog.h" #ifndef QT_NO_SSL static const char defaultUrl[] = ""; #else static const char defaultUrl[] = ""; #endif static const char defaultFileName[] = "index.html"; ProgressDialog::ProgressDialog(const QUrl &url, QWidget *parent) : QProgressDialog(parent) { setWindowTitle(tr("Download Progress")); setWindowFlags(windowFlags() & ~Qt::WindowContextHelpButtonHint); setLabelText(tr("Downloading %1.").arg(url.toDisplayString())); setMinimum(0); setValue(0); setMinimumDuration(0); } void ProgressDialog::networkReplyProgress(qint64 bytesRead, qint64 totalBytes) { setMaximum(totalBytes); setValue(bytesRead); } HttpWindow::HttpWindow(QWidget *parent) : QDialog(parent) , statusLabel(new QLabel(tr("Please enter the URL of a file you want to download.\n\n"), this)) , urlLineEdit(new QLineEdit(defaultUrl)) , downloadButton(new QPushButton(tr("Download"))) , launchCheckBox(new QCheckBox("Launch file")) , defaultFileLineEdit(new QLineEdit(defaultFileName)) , downloadDirectoryLineEdit(new QLineEdit) , reply(Q_NULLPTR) , file(Q_NULLPTR) , httpRequestAborted(false) { setWindowFlags(windowFlags() & ~Qt::WindowContextHelpButtonHint); setWindowTitle(tr("HTTP")); connect(&qnam, &QNetworkAccessManager::authenticationRequired, this, &HttpWindow::slotAuthenticationRequired); #ifndef QT_NO_SSL connect(&qnam, &QNetworkAccessManager::sslErrors, this, &HttpWindow::sslErrors); #endif QFormLayout *formLayout = new QFormLayout; urlLineEdit->setClearButtonEnabled(true); connect(urlLineEdit, &QLineEdit::textChanged, this, &HttpWindow::enableDownloadButton); formLayout->addRow(tr("&URL:"), urlLineEdit); QString downloadDirectory = QStandardPaths::writableLocation(QStandardPaths::TempLocation); if (downloadDirectory.isEmpty() || !QFileInfo(downloadDirectory).isDir()) downloadDirectory = QDir::currentPath(); downloadDirectoryLineEdit->setText(QDir::toNativeSeparators(downloadDirectory)); formLayout->addRow(tr("&Download directory:"), downloadDirectoryLineEdit); formLayout->addRow(tr("Default &file:"), defaultFileLineEdit); launchCheckBox->setChecked(true); formLayout->addRow(launchCheckBox); QVBoxLayout *mainLayout = new QVBoxLayout(this); mainLayout->addLayout(formLayout); mainLayout->addItem(new QSpacerItem(0, 0, QSizePolicy::Ignored, QSizePolicy::MinimumExpanding)); statusLabel->setWordWrap(true); mainLayout->addWidget(statusLabel); downloadButton->setDefault(true); connect(downloadButton, &QAbstractButton::clicked, this, &HttpWindow::downloadFile); QPushButton *quitButton = new QPushButton(tr("Quit")); quitButton->setAutoDefault(false); connect(quitButton, &QAbstractButton::clicked, this, &QWidget::close); QDialogButtonBox *buttonBox = new QDialogButtonBox; buttonBox->addButton(downloadButton, QDialogButtonBox::ActionRole); buttonBox->addButton(quitButton, QDialogButtonBox::RejectRole); mainLayout->addWidget(buttonBox); urlLineEdit->setFocus(); } void HttpWindow::startRequest(const QUrl &requestedUrl) { url = requestedUrl; httpRequestAborted = false; reply = qnam.get(QNetworkRequest(url)); connect(reply, &QNetworkReply::finished, this, &HttpWindow::httpFinished); connect(reply, &QIODevice::readyRead, this, &HttpWindow::httpReadyRead); ProgressDialog *progressDialog = new ProgressDialog(url, this); progressDialog->setAttribute(Qt::WA_DeleteOnClose); connect(progressDialog, &QProgressDialog::canceled, this, &HttpWindow::cancelDownload); connect(reply, &QNetworkReply::downloadProgress, progressDialog, &ProgressDialog::networkReplyProgress); connect(reply, &QNetworkReply::finished, progressDialog, &ProgressDialog::hide); progressDialog->show(); statusLabel->setText(tr("Downloading %1...").arg(url.toString())); } void HttpWindow::downloadFile() { const QString urlSpec = urlLineEdit->text().trimmed(); if (urlSpec.isEmpty()) return; const QUrl newUrl = QUrl::fromUserInput(urlSpec); if (!newUrl.isValid()) { QMessageBox::information(this, tr("Error"), tr("Invalid URL: %1: %2").arg(urlSpec, newUrl.errorString())); return; } QString fileName = newUrl.fileName(); if (fileName.isEmpty()) fileName = defaultFileLineEdit->text().trimmed(); if (fileName.isEmpty()) fileName = defaultFileName; QString downloadDirectory = QDir::cleanPath(downloadDirectoryLineEdit->text().trimmed()); if (!downloadDirectory.isEmpty() && QFileInfo(downloadDirectory).isDir()) fileName.prepend(downloadDirectory + '/'); if (QFile::exists(fileName)) { if (QMessageBox::question(this, tr("Overwrite Existing File"), 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 = openFileForWrite(fileName); if (!file) return; downloadButton->setEnabled(false); // schedule the request startRequest(newUrl); } QFile *HttpWindow::openFileForWrite(const QString &fileName) { QScopedPointer<QFile> file(new QFile(fileName)); if (!file->open(QIODevice::WriteOnly)) { QMessageBox::information(this, tr("Error"), tr("Unable to save the file %1: %2.") .arg(QDir::toNativeSeparators(fileName), file->errorString())); return Q_NULLPTR; } return file.take(); } void HttpWindow::cancelDownload() { statusLabel->setText(tr("Download canceled.")); httpRequestAborted = true; reply->abort(); downloadButton->setEnabled(true); } void HttpWindow::httpFinished() { QFileInfo fi; if (file) { fi.setFile(file->fileName()); file->close(); delete file; file = Q_NULLPTR; } if (httpRequestAborted) { reply->deleteLater(); reply = Q_NULLPTR; return; } if (reply->error()) { QFile::remove(fi.absoluteFilePath()); statusLabel->setText(tr("Download failed:\n%1.").arg(reply->errorString())); downloadButton->setEnabled(true); reply->deleteLater(); reply = Q_NULLPTR; return; } const QVariant redirectionTarget = reply->attribute(QNetworkRequest::RedirectionTargetAttribute); reply->deleteLater(); reply = Q_NULLPTR; if (!redirectionTarget.isNull()) { const QUrl redirectedUrl = url.resolved(redirectionTarget.toUrl()); if (QMessageBox::question(this, tr("Redirect"), tr("Redirect to %1 ?").arg(redirectedUrl.toString()), QMessageBox::Yes | QMessageBox::No) == QMessageBox::No) { downloadButton->setEnabled(true); return; } file = openFileForWrite(fi.absoluteFilePath()); if (!file) { downloadButton->setEnabled(true); return; } startRequest(redirectedUrl); return; } statusLabel->setText(tr("Downloaded %1 bytes to %2\nin\n%3") .arg(fi.size()).arg(fi.fileName(), QDir::toNativeSeparators(fi.absolutePath()))); if (launchCheckBox->isChecked()) QDesktopServices::openUrl(QUrl::fromLocalFile(fi.absoluteFilePath())); downloadButton->setEnabled(true); } void HttpWindow::httpReadyRead() { // this slot gets called every time the QNetworkReply has new data. // We read all of its new data and write it into the file. // That way we use less RAM than when reading it at the finished() // signal of the QNetworkReply if (file) file->write(reply->readAll()); } void HttpWindow::enableDownloadButton() { downloadButton->setEnabled(!urlLineEdit->text().isEmpty()); } void HttpWindow::slotAuthenticationRequired(QNetworkReply*,QAuthenticator *authenticator) { QDialog authenticationDialog; Ui::Dialog ui; ui.setupUi(&authenticationDialog); authenticationDialog.adjustSize(); ui.siteDescription->setText(tr("%1 at %2").arg(authenticator->realm(),; // Did the URL have information? Fill the UI // This is only relevant if the URL-supplied credentials were wrong ui.userEdit->setText(url.userName()); ui.passwordEdit->setText(url.password()); if (authenticationDialog.exec() == QDialog::Accepted) { authenticator->setUser(ui.userEdit->text()); authenticator->setPassword(ui.passwordEdit->text()); } } #ifndef QT_NO_SSL void HttpWindow::sslErrors(QNetworkReply*,const QList<QSslError> &errors) { QString errorString; foreach (const QSslError &error, errors) { if (!errorString.isEmpty()) errorString += '\n'; errorString += error.errorString(); } if (QMessageBox::warning(this, tr("SSL Errors"), tr("One or more SSL errors has occurred:\n%1").arg(errorString), QMessageBox::Ignore | QMessageBox::Abort) == QMessageBox::Ignore) { reply->ignoreSslErrors(); } } #endif

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